IEEE / PESpes-spdc.org/system/files/filedepot/21/C62DEF-May06.pdf · C62.92.2 17. C62.92.4 18. C62.92.5 19. IEEE STD 32-1990 Surge Protective Devices Committee C62 Definitions 2 AC

IEEE / PES

SURGE PROTECTIVE DEVICES COMMITTEE BIBLIOGRAPHY SUBCOMMITTEE

C62 SERIES DEFINITIONS

Approved May 03, 2006

Surge Protective Devices Committee C62 Definitions

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DEFINITIONS FROM C62 SERIES DOCUMENTS

Explanatory Comments Definitions in bold indicate that there are two or more definitions for the same term and the definition in bold is SPDC preferred. Definitions in shade indicate that this definition will be recommended for deletion or is not appropriate anymore. Definitions in Italics are new since May, 2001. Definitions followed by a superscript “a” are identical to a definition that appears in IEEE Std. 100-1996. Definitions were taken from latest issues of the following Standards: 1. C62.1 2. C62.2 3. C62.11 4. C62.22 5. C62.31 6. C62.32 7. C62.33 8. C62.35

9. C62.36 10. C62.37-96 11. C62.41 12. C62.42

13. C62.45 14. C62.47 15. C62.92.1 16. C62.92.2 17. C62.92.4 18. C62.92.5 19. IEEE STD 32-1990


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AC STANDBY POWER (VARISTOR) Varistor ac power dissipation measured at rated rms voltage Vm(ac). C62.33-89 ACCEPTANCE TEST A test to demonstrate the degree of compliance of a device with purchaser's requirements. STD 32-90 AIR DISCHARGE METHOD A method of ESD testing in which the charged electrode of the ESD simulator approaches the Unit Under Test (UUT) or coupling plane. The discharge is actuated by a spark in air to the UUT or coupling plane. C62.38-1995 AIR GAP SURGE ARRESTER A gap or gaps, in air at ambient atmospheric pressure, designed to protect apparatus and personnel or both, from high transient voltages. C62.32-87 AIR GAP SURGE PROTECTOR A protective device, consisting of one or more air gap surge arresters; optional fuses, short-circuiting devices, etc; and a mounting assembly, for limiting surge voltages on low voltage (600 V rms or less) electrical and electronic equipment or circuits. C62.32-87 AIR INSULATION AND SWITCHGEAR For air insulation and switchgear: 250 x 2500 µs. C62.2-87 AMBIENT TEMPERATURE The temperature of the medium such as air, water, or earth into which the heat of the equipment is dissipated. STD 32-90 ANODE The electrode by which current enters the thyristor, when the thyristor is in the on-state with the gate open-circuited.a C62.37-96

ANTISTATIC A property of materials that resist triboelectric charging. C62.47-92 APPROACH SPEED The rate at which the intruder approaches the receptor. C62.47-92 ARC CURRENT The current that flows after breakdown when the circuit impedance allows a current that exceeds the glow-to-arc transition current. Sometimes called arc mode current. C62.31-87 ARC VOLTAGE The voltage drop across the arrester during arc current flow. Sometimes called arc mode voltage. C62.31-87 ARRESTER DISCHARGE CURRENT The surge current that passes through an arrester when sparkover occurs. C62.2-87 The current that flows through an arrester due to a surge. C62.22-91 ARRESTER DISCHARGE VOLTAGE The voltage that appears across the terminals of an arrester during passage of discharge current. C62.22-91 NOTE: Published discharge voltages are determined by tests using 8/20µs impulses. C62.2-87 ARRESTER DISCONNECTOR A means for disconnecting an arrester in anticipation of or after, a failure in order to prevent a permanent fault on the circuit and to give indication of a failed arrester. NOTE: Clearing of the power current through the arrester during disconnection generally is a function of the nearest source-side overcurrent-protective device. C62.1-89 & C62.11-87


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ARRESTER DUTY CYCLE RATING The designated maximum permissible root-mean-square (rms) value of power-frequency voltage between its line and earth terminals at which it is designed to perform it's duty cycle. C62.22-91 ARRESTER RATING (for silicon carbide arresters only) The designated maximum permissible operating voltage between an arrester's terminals at which it is designed to perform it's duty cycle. It is the voltage rating specified on the nameplate. C62.1-84, C62.2-87 ARRESTER RECOVERY VOLTAGE The crest voltage that occurs across the terminals of an arrester following a unit operation. C62.2-87 ARRESTER SPARKOVER A disruptive discharge between electrodes of an arrester. C62.2-87 ARRESTER UNIT Any section of a multi-unit arrester. C62.11-1993 ARRESTER, DEADFRONT TYPE An arrester assembled in a shielded housing providing system insulation and conductive ground shield, intended to be installed in an enclosure for the protection of underground and pad-mounted distribution equipment and circuits. C62.11-1993 ARRESTER, DISTRIBUTION, HEAVY DUTY CLASS An arrester normally used to protect overhead distribution systems exposed to severe lightning currents.

C62.11-1993 ARRESTER, DISTRIBUTION, LIGHT DUTY CLASS An arrester normally installed on and used to protect underground distribution systems where the major portion of the lightning stroke current is discharged by an arrester located at the overhead line/cable junction. C62.11-1993 ARRESTER, DISTRIBUTION, NORMAL DUTY CLASS An arrester normally used to protect overhead distribution systems exposed to normal lightning currents.

C62.11-1993 ARRESTER, RISER POLE TYPE An arrester for pole mounting normally used to protect underground distribution cable and equipment.

C62.11-1993 BACK FILTER A filter inserted in the power line feeding an equipment to be surge tested; this filter has a dual purpose: (1) To prevent the applied surge from being fed back to the power source where it may (might according to the word usage in this guide) cause damage. (2) To eliminate loading effects of the power source on the surge generator. See decoupling network. C62.45-92 BACKUP AIR-GAP DEVICE An air-gap device connected in parallel with a sealed gas-tube device, having a higher breakdown voltage than the gas tube, which provides a secondary means of protection in the event of a venting to atmosphere by the primary gas-tube device. C62.31-87 & C62.32-87 BASIC IMPULSE INSULATION LEVEL (BIL) A reference impulse insulation strength expressed in terms of the crest value of withstand voltage of standard full impulse voltage wave. NOTE: See ANSI C92.1-82 C62.1-89 & C62.11-87


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BASIC LIGHTNING IMPULSE INSULATION LEVEL The electrical strength of insulation expressed in terms of the crest value of a standard lightning impulse. The basic lightning impulse insulation level (BIL) may be either a statistical BIL, or a conventional BIL, defined as follows; (see ANSI C92.1-82) C62.2-87) A specific insulation level expressed in terms of the crest value of a standard lightning impulse; see ANSI C92.1-1982. C62.22-91 BASIC SWITCHING IMPULSE INSULATION LEVEL The electrical strength of insulation expressed in terms of the crest value of a standard switching impulse. The basic switching impulse insulation level (BSL) may be either a statistical BSL, or a conventional BSL, defined as follows; (see ANSI C92.2-82) C62.2-87 A specific insulation level expressed in terms of the crest value of a standard switching impulse; see ANSI C92.182 C62.22-91 BIDIRECTIONAL THYRISTOR A thyristor having substantially the same switching behavior in the first and third quadrants of the principal voltage-current characteristic. C62.37-96 BLIND SPOT A limited range within the total domain of application of a device, generally at values inferior to the maximum rating. Operation of the equipment or of the protective device might fail in that limited range despite the device's demonstration of satisfactory performance at maximum ratings. C62.45-92 BLOCKING A term describing the state of a semiconductor device or junction that imposes high resistance to the passage of current. C62.37-96 BODY/FINGER ESD An electrostatic discharge from an intruding human finger or hand. Also called body /finger discharge. C62.47-92 BODY/METAL ESD See hand/metal ESD. Also called body/metal discharge. C62.47-92 BREAKDOWN A phenomena occurring in a reverse biased semiconductor junction, the initiation of which is observed as a transition from a region of high dynamic resistance to a region of substantially lower dynamic resistance for increasing magnitude of reverse current. C62.37-96 BREAKDOWN The abrupt transition of the gap resistance from a practically infinite value to a relatively low value. In the case of a gap, this is sometimes referred to as sparkover or ignition. See: sparkover. C62.31-87 & C62.32-87 BREAKDOWN CURRENT (I(BR)) The current through the device in the breakdown region. C62.37-96 BREAKDOWN REGION The portion of the characteristic that starts with the transition from the high dynamic resistance off state to a substantially lower dynamic resistance and extending to the switching point. C62.3 7-96 BREAKDOWN VOLTAGE (V(BR)) The voltage across the device in the breakdown region (prior to the switching point/ at a specified breakdown current, I(BR). C62. 37-96


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BREAKDOWN VOLTAGE, ac The minimum rms value of a sinusoidal voltage at frequencies between 15 Hz and 62 Hz that results in arrester sparkover. C62.31-87 BREAKDOWN VOLTAGE, dc The minimum slowly rising do voltage that causes breakdown or sparkover when applied across the terminals of an arrester. C62.31-87 & C62.32-87 BREAKOVER CURRENT (I(BO)) The instantaneous current flowing at the breakover voltage, V(BO) C62.37-96 BREAKOVER POINT Any point on the principal voltage-current characteristic for which the differential resistance is zero and where the principal voltage reaches a maximum value.a C62.37-96 BREAKOVER VOLTAGE (V(BO)) The maximum voltage across the device in or at the breakdown region measured under specified voltage rate of rise and current rate of rise. C62.37-96 BRUSH-BY An electrostatic discharge from the human torso, such as from the hip or shoulder. Also called brush-by ESD or brush-by discharge. C62.47-92 CAPACITANCE (VARISTOR) Capacitance between the two terminals of the varistor measured at specified frequency and bias. C62.33-89 CAPACITANCE Capacitance between the two terminals of an avalanche surge suppressor measured at specific frequency and bias.

C62.35-87

CATHODE The electrode by which current leaves the thyristor, when the thyristor is in the on-state with the gate open-circuited.a NOTE: This term does not apply to bi-directional thyristors. C62.37-96 CERTIFICATION TESTS Tests made, when required, to verify selected performance characteristics of a product or representative samples thereof. C62.1-89 CERTIFICATION TESTS Tests run on a regular, periodic basis to verify that selected, key performance characteristics of a product or representative samples thereof have remained within performance specifications. C62.11-87 CHARACTERISTIC An inherent and measurable property of a device. Such a property may be electrical, mechanical, thermal, hydraulic, electromagnetic, or nuclear, and can be expressed as a value for stated or recognized conditions. A characteristic may also be a set of related values, usually shown in graphical form.a C62.37-96 CHARGE VOLTAGE The voltage difference between the intruder and the receptor just prior to an ESD. C62.47-92 CIRCUIT PACK A printed circuit board (PCB) populated with components, i.e. a PCB assembly, also called a Feature Card. C62.38-1995


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CLAMPING FACTOR Ratio of the measured clamping voltage (VC) at a specified peak pulse current IPP to breakdown voltage. CF=VC/V(BR) C62.35-87 CLAMPING VOLTAGE Peak voltage across the SPD measured under conditions of a specified peak pulse current and specified wave form. NOTE-Peak voltage and peak current are not necessarily coincident in time. C62.37-96 CLAMPING VOLTAGE Peak voltage across the varistor measured under conditions of a specified peak pulse current and specified waveform. a C62.33-89 NOTE: Peak voltage and peak current are not necessarily coincidental in time.a

CLASSES OF GROUNDING A specific range of degree of grounding; for example, effectively and non-effectively. C62.92.1-87 CLASSIFICATION CURRENT The designated current used to perform the classification tests. C62.11-87 CLASSIFICATION OF ARRESTERS Arrester classification is determined by prescribed test requirements. These classifications are: (1) Station arrester (2) Intermediate arrester (3) Distribution arrester (a) Heavy duty (b) Normal duty (4) Secondary arrester C62.1-89 & C62.11-87 CLEARING The characteristic of some types of air gap surge arresters to exhibit a low resistance and then to revert to a high resistance state as a result of an external influence. C62.32-87 CLEARING SOURCE A defined electrical source which is intentionally applied as a clearing stimulus to an air gap surge protective device under laboratory test conditions. This stimulus is intended to stimulate conditions encountered during normal usage. C62.32-87 COEFFICIENT OF GROUNDING The ratio ELG/ELL, expressed as a percentage, of the highest root-mean-square line-to-ground power-frequency voltage ELG, on a sound phase, at a selected location, during a fault to ground affecting one or more phases to the line-to-line power-frequency voltage ELL which (that) would be obtained, at the selected location, with the fault removed. C62.2-87 & (C62.22-91) NOTES: (1) Coefficients of grounding for three-phase systems are calculated from the phase-sequence

impedance components as viewed from the selected location. For machines, use the subtransient reactance.

(2) The coefficient of grounding is useful in the determination of an arrester rating for a selected location.

(3) A value not exceeding 80% is obtained approximately when, for all system conditions, the ratio of zero-sequence reactance to positive-sequence reactance is positive and less than 3, and the ratio of zero-sequence resistance to positive sequence reactance is positive and less than 1. C62.1-89


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COMPONENT SURGE-PROTECTIVE DEVICE (COMPONENT SPD) A discrete surge protective device involving a single specific technology and intended to be installed as a component within a surge protector or as a component housed within the equipment to be protected. NOTE-- Examples are “component air gap surge-protective device”, “component gas tube surge-protective device”, “component varistor surge-protective device” and “component avalanche junction semiconductor surge-protective device”. The term surge arrester is also used to describe a single component. C62.42-2005 COMPONENT SURGE-PROTECTIVE DEVICE – VOLTAGE LIMITING TYPE A component surge-protective device that has a high impedance when no surge is present, but that can limit voltage by progressively and smoothly reducing its impedance when responding to a surge. Examples are component varistor and avalanche junction semiconductor surge-protective devices. NOTE--also commonly referred to as a “voltage clamping” device. C62.42-2005 COMPONENT SURGE-PROTECTIVE DEVICE – VOLTAGE LIMITING TYPE A component surge-protective device that has a high impedance when no surge is present, but that can have a sudden voltage collapse to a low impedance state when responding to a surge. Examples are component air gap and gas tube surge-protective devices. NOTE--also commonly referred to as “crowbar” devices. C62.42-2005 CONFORMANCE TEST Tests made, when required, to demonstrate selected performance characteristics of a product or representative samples thereof. C62.1-89 & C62.11-87 CONTACT DISCHARGE METHOD A method of ESD testing in which the electrode of the ESD simulator is in firm conductive contact with the UUT or coupling plane prior to and during the discharge. The discharge is actuated by a switching device, e.g. a relay, within the simulator. C 62.38 -1995 CONVENTIONAL BIL Applicable specifically to nonself-restoring insulations. The crest value of a standard lightning impulse for which the insulation shall not exhibit disruptive discharge when subjected to a specific number of applications of this impulse under specified conditions. C62.2-87 CONVENTIONAL BSL Applicable specifically to nonself-restoring insulations. The crest value of a standard switching impulse for which the insulation does not exhibit disruptive discharge when subjected to a specific number of applications of this impulse under specific conditions. C62.2-87 COORDINATION OF INSULATION The process of correlating the insulation strengths of electric equipment with expected overvoltages and with the characteristics of surge protective devices: see ANSI 92.1-82, C62.2-87 & C62.22-91 COUPLER A device, or combination of devices, used to feed a surge from a generator to powered equipment while limiting the flow of current from the power source into the generator. See: coupling network. C62.45-92 COUPLING FACTOR The ratio of the induced voltage to the inducing voltage on parallel conductors. e.g. At the tower the shield or coupling wires and tower crossarms are at practically the same potential (because of lightning stroke travel time). The stress across the insulator string is (1 minus coupling factor) multiplied by (tower top potential) Stress = (1. 0 - Kƒc) x VTT where Kƒc is the coupling factor and VTT is the tower top voltage. C62.23 - 1995


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COUPLING NETWORK Electrical circuit for the purpose of transferring energy from one circuit to another. See: coupler. C62.45-92 COUPLING WIRE A conductor attached to the transmission line structure, and below the phase wires, with proper clearance, and connected to the grounding system of the towers or pole supporting the line. C62.23 - 1995 CREST (PEAK) VALUE (OF A WAVE, SURGE, OR IMPULSE) The maximum value that it (an impulse) attains. C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 CREST (PEAK) VALUE (OF A WAVE, SURGE, OR IMPULSE) The maximum value that it attains. C62.37-96 CRITICAL RATE OF RISE OF OFF-STATE VOLTAGE (dv/dt) The maximum rate of rise of voltage (below VDRM) that will not cause switching from the off-state to the on-state. C62.37-96 CRITICAL RATE OF RISE OF ON-STATE CURRENT (di/dt) Rated value of the rate of rise of current which the device can withstand without damage. C62.37-96 CURRENT TURNOFF TIME The time required for the arrester to restore itself to a nonconducting state following a period of conduction. This applies only to a continuous specified dc potential under a specified circuit condition. C62.31-87 CURRENT TURNOFF TIME The time required for the arrester to restore itself to a non-conducting state following a period of conduction. This definition applies only to a condition where the arrester is exposed to a continuous specified dc potential under a specified circuit condition. C62.32-87 DC HOLDOVER In applications where dc voltage exists on a line, a holdover condition is one in which a surge-protective device continues to conduct after it is subjected to an impulse large enough to cause breakdown. Factors that affect the time required to recover from the conducting state include the dc voltage and the dc current. C62.31-87 & C62.32-87 DC HOLDOVER VOLTAGE The maximum dc voltage across the terminals of an arrester under which it may be expected to clear and to return to the high-impedance state after the passage of a surge, under specified circuit conditions. C62.31-87 & C62.32-87 DC STANDBY CURRENT (VARISTOR) Varistor current measured at rated voltage. Vm(dc). C62.33-89 DECOUPLING NETWORK Electrical circuit for the purpose of preventing an EFT signal applied to the equipment under test from affecting other devices, equipment or systems which are not under test. See back filter. C62.45-92 DEFLECTOR A means for directing the flow of the gas discharge from the vent of the arrester. C62.1-89 & C62.11-87 DESIGN TESTS Tests made by the manufacturer on each design to establish the performance characteristics and to demonstrate compliance with the appropriate standards of the industry. Once made, they need not be repeated unless the design is changed so as to modify performance. C62.1-89 & C62.11-87 DES Discharge Electrostatic; an alternative name for ESD. C62.47-92


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DIODE A semiconductor device having two terminals and exhibiting a nonlinear voltage-current characteristic; in more restricted usage, a semiconductor device that has the asymmetrical voltage-current characteristic exemplified by a single p-n junction.a C62.37-96 DIRECT ESD EVENT An ESD event taking place between an intruder and a receptor in which the intruder or the receptor, or both, is an equipment victim. C62.47-92 DISCHARGE COUNTER A means for recording the number of arrester discharge operations. C62.1-89 & C62.11-87 DISCHARGE CURRENT The surge current that flows through an arrester when sparkover occurs. C62.1-89 DISCHARGE CURRENT The current that flows through an arrester when sparkover occurs. C62.31-87 & C62.32-87 DISCHARGE CURRENT The surge current that flows through an arrester. C62.11-87 DISCHARGE INDICATOR A means for indicating that the arrester has discharged. C62.1-89 & C62.11-87 DISCHARGE VOLTAGE The voltage that appears across the terminals of an arrester during the passage of discharge current.

C62.31-87 & C62.1-89 & C62.11-87 & C62.32-87 DISCHARGE WITHSTAND CURRENT RATING The specified magnitude and wave shape of a discharge current that can be applied to an arrester a specified number of times without causing damage to it. C62.1-89 & C62.11-87 DISCHARGE-VOLTAGE-CURRENT CHARACTERISTIC The variation of the crest values of discharge voltage with respect to discharge current. C62.31-87 NOTE: This characteristic is normally shown as a graph based on three or more current-surge measurements of the same wave shape but of different crest values. C62.1-89 & C62.11-87 DISRUPTIVE DISCHARGE The sudden and large increase in current through an insulating medium, due to the complete failure of the medium under the electrostatic stress. C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 DUTY CYCLE VOLTAGE RATING The designated maximum permissible voltage between its terminals at which an arrester is designed to perform its duty cycle. C62.11-87 DYNAMIC IMPEDANCE (VARISTOR) A measure of small signal impedance at a given operating point as defined by: ZX=dVX/dIX. C62.33-89 EQUIPMENT UNDER TEST (EUT) A representative component, unit or system to be used for evaluation purposes. C62.45-92 EQUIPMENT VICTIM The electronic equipment or subassembly which is subjected to the effects associated with an ESD event. It may be the intruder or receptor, or it may be in proximity to the discharge between the intruder and receptor, and therefore subjected to the stress of ESD related electromagnetic fields. C62.47-92


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ESD CURRENT WAVE The waveform of the discharge current between an intruder and a receptor. C62.47-92 ESD EVENT Includes the ESD current, electromagnetic fields and corona effects before and during an ESD. C62.47-92 ESD Electrostatic Discharge: the sudden transfer of charge between bodies of differing electrostatic potentials.

C62.47-92 FAIL-SAFE Use of this term is not recommended in C62 series documents. C62.32-87 FAST APPROACH Approach speeds that engender short, sub-nanosecond rise-time ESD current waves. Fast approach speed depends on the voltage difference between the intruder and receptor, e.g. for rounded electrodes of 8 mm diameter, greater than 0.05m/s, lm/s, and 10m/s at charge voltages of 4 kV, 8 kV and 16 kV respectively. C62.47-92 FAULT CURRENT The current from the connected power system that flows in a short circuit. C62.1-89 & C62.11-87 FAULT-CURRENT WITHSTAND The maximum rms symmetrical fault current of a specified duration that a failed distribution class arrester will withstand without an explosive fracture of the housing. C62.1-89 FLASHOVER A disruptive discharge around or over the surface of a solid or liquid insulator.

C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 FOLLOW (POWER) CURRENT The current from the connected power source that flows through an arrester during and following the passage of discharge current. C62.31-87 & C62.1-89 & C62.2-87 & C62.32-87 FORWARD CURRENT (IF) The current through the device in the forward conducting state. C62.37-96 FORWARD DIRECTION (1) The direction of current in a p-n junction that results when the p-type semiconductor region is at a positive potential relative to the n-type region. (2) The direction of current in a semiconductor device that results when the p-type semiconductor region connected to one terminal is at a positive potential relative to the n-type region connected to the other terminal. NOTE-This definition does not apply if one or more junctions are connected in series with at least one other junction whose p and n regions are reversed. C62.37-96 FORWARD VOLTAGE (VF) The voltage across the device in the forward conducting state at a specified current IF C62.37-96 FORWARD VOLTAGE Peak voltage measured across the avalanche surge suppressor for a specified forward pulse current IFS. Applies to asymmetrical bi-directional avalanche junction surge suppressor only. C62.35-87 FORWARD/REVERSE CONDUCTING QUADRANT A quadrant of the principal voltage-current characteristic in which the device exhibits a forward direction conduction state. This will be quadrant 1 for a forward conducting thyristor SPD and quadrant 3 for a reverse conducting thyristor SPD. C62.37-96


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FORWARD-CONDUCTING DIODE THYRISTOR SPD A two-terminal internally triggered thyristor SPD that switches only for negative terminal-2 (cathode) voltage and conducts large currents at positive terminal-2 voltages comparable in magnitude to the on-state voltage. NOTES: 1-In conventional thyristor applications where the cathode is the common terminal, this device

would be called a reverse-conducting diode thyristor. 2-When terminal 2 (cathode) is positive, the device characteristics are similar to those of a forward biased diode. 3-When terminal 2 (cathode) is negative, the device characteristics are similar to those of a breakover-triggered SCR. C62.37-96

FORWARD-CONDUCTING TRIODE THYRISTOR SPD A three-terminal thyristor SPD that switches only for negative main terminal-2 (cathode) voltage and conducts large currents at positive main terminal-2 voltages comparable in magnitude to the on-state voltage. NOTES: 1-In conventional thyristor applications where the cathode is the common terminal, this device

would be called a reverse-conducting triode thyristor. 2-Application of an appropriate fixed gate voltage allows switching to take place at voltages well below the intrinsic breakover value. 3-When main terminal 2 (cathode) is positive, the device characteristics are similar to those of a forward biased diode. C62.37-96

FRONT-OF-WAVE IMPULSE SPARKOVER VOLTAGE The impulse sparkover voltage with a wave front that rises at a uniform rate and causes sparkover on the wave front. C62.11-87 FURNITURE ESD An electrostatic discharge in which the intruder is an inanimate object such as a cart or chair, with or without a human in electrical contact with the object. C62.47-92 GAPLESS Not possessing gaps, series or parallel, as in "gapless arrester". C62.11-87 GAS-TUBE SURGE ARRESTER A gap, or gaps, in an enclosed discharge medium, other than air at atmospheric pressure, designed to protect apparatus or personnel, or both, from high transient voltages. C62.31-87 GATE An electrode connected to one of the semiconductor regions to introduce a control current. C62.37-96 GATE REVERSE CURRENT, ADJACENT TERMINAL OPEN (IGAO, IGKO) The current through the gate terminal when a specified gate bias voltage, VG, is applied and the cathode terminal for a p-gate device or anode terminal for an n-gate device is open circuited. C62.37-96 GATE REVERSE CURRENT, FORWARD CONDUCTING STATE (IGAF, IGKF) The current through the gate terminal when a specified gate bias voltage, VG, is applied and a specified forward conduction current, IF, is flowing. C62.37-96 GATE REVERSE CURRENT, MAIN TERMINALS SHORT CIRCUITED (IGAS, IGKS) The current through the gate terminal when a specified gate bias voltage, VG, is applied and the cathode terminal for a p-gate device or anode terminal for an n-gate device is short circuited to the third terminal. C62.37-96 GATE REVERSE CURRENT, ON-STATE (IGAT, IGKT) The current through the gate terminal when a specified gate bias voltage, VG, is applied and a specified on-state current, IT is flowing. C62.37-96 GATE SWITCHING CHARGE (QGS ) The charge through the gate terminal, under impulse conditions, during the transition from the off-state to the switching point, when a specified gate bias voltage, VG, is applied. C62.37-96


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GATE-TO-ADJACENT TERMINAL BREAKOVER VOLTAGE (VGK(BO); VGA(BO)) The gate to cathode voltage for a p-type device or gate to anode voltage for an n-gate device at the breakover point. This is equivalent to the voltage difference between the breakover voltage, V(BO), and the specified gate voltage, VG.. C62.37-96 GATE-TO-ADJACENT TERMINAL PEAK OFF-STATE VOLTAGE (VGDM) The maximum gate to cathode voltage for a p-gate device or gate to anode voltage for an n-gate device that may be applied such that a specified off-state current, ID, at a rated off-state voltage, VD, is not exceeded. C62.37-96 GLOW CURRENT The current that flows after breakdown when circuit impedance limits the follow current to a value less than the glow-to-arc transition current. It is sometimes called the glow mode current. C62.31-87 GLOW VOLTAGE The voltage drop across the arrester during glow-current flow. It is sometimes called the glow mode voltage.

C62.31-87 GLOW-TO-ARC TRANSITION CURRENT The current required for the arrester to pass from the glow mode into the arc mode. C62.31-87 GPR Acronym for ground potential rise. see: ground potential rise. C62.23 - 1995 GRADING OR CONTROL RING A metal part, usually circular or oval in shape, mounted to modify electrostatically the voltage gradient or distribution. C62.1-89 & C62.11-87 GROUND END (OF A NEUTRAL GROUNDING DEVICE) The end or terminal that is grounded directly or through another device. STD 32-90 GROUND POTENTIAL RISE The voltage that a station grounding grid may attain relative to distant grounding point assumed to be at the potential of remote earth. C62.23 - 1995 GROUND TERMINAL The conducting part provided for connecting the arrester to ground. C62.1-89 & C62.11-87 GROUNDED PARTS Parts that are intentionally connected to ground. STD 32-90 GROUNDED SYSTEM An electric system in which at least one conductor or point (usually the neutral conductor or neutral point of transformer or generator windings) is intentionally grounded, either solidly or through a grounding device. C62.1-89 A system of conductors in which at least one conductor or point (usually the neutral conductor or neutral point of transformer or generator windings) is intentionally grounded, either solidly or through a current-limiting device. STD 32 - 90 (C62.91) GROUND-FAULT NEUTRALIZER GROUNDED Reactance grounded through such values of reactance that, during a fault between one of the conductors and earth. the rated-frequency current flowing in the grounding reactances and the rated-frequency capacitance current flowing between the unfaulted conductors and earth shall be substantially equal. In the fault, these two components of fault current will be substantially 180 degrees out of phase. NOTE: When a system is ground-fault neutralizer grounded, it is expected that the quadrature component of the rated-frequency single-phase-to-ground fault current will be so small that an arc fault in air will be self extinguishing. STD 32-90


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GROUND-FAULT NEUTRALIZER A grounding device that provides an inductive component of current in a ground fault that is substantially equal to and therefore neutralizes the rated-frequency capacitive component of the ground-fault current, thus rendering the system resonant grounded. STD 32-90 GROUNDING DEVICE An impedance device used to connect conductors of an electric system to ground for the purpose of controlling the ground current or voltage to ground. NOTE: The grounding device may consist of a grounding transformer or a neutral grounding device, or a combination of these. Protective devices, such as lightning arresters, may also be included as an integral part of the device. STD 32-90 GROUNDING TRANSFORMER A transformer intended primarily to provide a neutral point for grounding purposes. NOTE: It may be provided with a delta winding in which resistors or reactors may be connected. STD 32-90 HAND/METAL ESD An electrostatic discharge from an intruding human hand which occurs from an intervening metal object such as a ring, tool, key, etc. Also called hand/metal discharge. C62.47-92 HAND-TO-METAL IMPEDANCE The impedance between the human hand and the metal object with which it is associated in a hand/metal ESD. The metal object is usually the intruder discharge electrode. Examples of hand-to-metal impedance include resistance and capacitance between the fingers and a key, between the wrist and a metal watch or bracelet, and between the hand and screwdriver. C62.47-92 HOLDING CURRENT (IH) The minimum current required to maintain the device in the on-state. C62.37-1996 IMPEDANCE GROUNDED Grounded through impedance. NOTE: The components of the impedance need not be at the same location. STD 32-90 IMPEDANCE VOLTAGE Comprises an effective resistance component corresponding to the impedance losses, and a reactance component corresponding to the flux linkages of the winding. STD 32-90 IMPULSE A surge of unidirectional polarity. a C62.1-89 & C62.2-87 & C62.11-87 & C62.22-87 & 62.37-96 IMPULSE FLASHOVER VOLTAGE The crest voltage of an impulse causing a complete disruptive discharge through the air between electrodes of a test specimen. STD 32-90 IMPULSE PROTECTIVE LEVEL For a defined wave shape, the higher of the maximum sparkover value or the corresponding discharge-voltage value. C62.11-87 IMPULSE PROTECTIVE VOLT-TIME CHARACTERISTIC The discharge-voltage time response of the device to impulses of a designated wave shape and polarity, but of varying magnitudes. C62.11-87 IMPULSE RESET TIME t(Reset) The time taken for a device to switch back into the off-state, in the presence of a specified value of dc short-circuit current, after being switched into the on state by a specified impulse. C62.37-96


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IMPULSE SPARKOVER VOLTAGE The highest value of voltage attained by an impulse of a designated wave shape and polarity applied across the terminals of an arrester (that will cause sparkover) prior to the flow of discharge current. Sometimes referred to as surge or impulse breakdown voltage. C62.31-87 & C62.32-87 & C62.1-89 & (C62.11-87) IMPULSE SPARKOVER VOLTAGE-TIME CURVE (ARRESTER) A curve that relates the impulse sparkover voltage to the time to sparkover. C62.31-87 IMPULSE SPARKOVER VOLT-TIME CHARACTERISTIC The (gap) sparkover response of the device to impulses of a designated wave shape and polarity, but of varying magnitudes. NOTE: For an arrester, this characteristic is shown by a graph of values of crest voltage plotted against time to sparkover. C62.1-89 & (C62.11-87) IMPULSE TESTS Dielectric tests in which the voltage applied is an impulse voltage of specified wave shape. The wave shape of an impulse test wave is the graph of the wave as a function of time or distance. NOTE: It is customary in practice to express the wave shape by a combination of two numbers, the first part of which represents the wave front and the second the time between the beginning of the impulse and the instant at which one-half crest value is reached on the wave tail, both values being expressed in microseconds, such as a 1.2 x 50 microsecond wave. STD 32-90 IMPULSE WAVE A unidirectional wave of current or voltage of very short duration containing no appreciable oscillatory components.a

NOTE - In the case of the 8/20 wave an opposite polarity wave tail underswing of up to 30% is allowed.a

C62.37-96 IMPULSE WITHSTAND VOLTAGE The crest value of an impulse that, under specified conditions, can be applied without causing a disruptive discharge. C62.1-89 & C62.11-87 The crest value of an applied impulse voltage which does not cause a flashover, puncture, or disruptive discharge on the test specimen. STD 32-90 INCREMENTAL SURGE RESISTANCE Resistance composed of thermal and nonlinear avalanche characteristics calculated between two instantaneous sets of values for peak pulse current (Ipp) and clamping voltage (VC) with a specified waveform. C62.35-87

INDIRECT ESD EVENT An ESD event taking place between an intruder and a receptor, in proximity to equipment which is the victim.

C62.47-92 INDOOR ARRESTER An arrester that, because of its construction, shall (must) be protected from the weather. C62.1-89 & (C62.11-87) INDUCED-POTENTIAL TEST A dielectric test in which the test voltage is an alternating voltage of suitable frequency, applied or induced between the terminals. STD 32-90

RS

VC2 VC1I PP2 I PP1

=−

−


15

INERT GAS-PRESSURE SYSTEM A method of oil preservation in which the interior of the tank is sealed from the atmosphere, over the temperature range specified, by means of a positive pressure of inert gas maintained from a separate inert-gas source and reducing-valve system. STD 32-90 INHIBITED OIL Mineral transformer oil to which a synthetic oxidation inhibitor has been added. STD 32-90 INITIAL CURRENT PULSE The sub-nanosecond rise time, and <1 to perhaps 3 nanosecond duration pulse that can occur at the start of the current wave from an ESD. Also called initial pulse, initial spike and fast discharge mode. Its leading edge is the initial slope. C62.47-92 INITIAL SLOPE The slope, in Amps per nanosecond (A/ns), which occurs at the start of the ESD current wave. Also termed rising slope. C62.47-92 INSULATION CLASS (OF A GROUNDING DEVICE) A number that defines the insulation levels of the device. STD 32-90 INSULATION LEVEL A combination of voltage values (both power-frequency and impulse) that characterize the insulation of an equipment with regard to its capability of withstanding dielectric stresses. C62.22-91 INSULATION RESISTANCE The equivalent insulation resistance of the device, computed by: VD / ID C62.37-96 INTRUDER ELECTRODE GEOMETRY The size and shape of that surface of the intruder, termed the intruder electrode, at which the ESD takes place.

C62.47-92 INTRUDER The body which is in motion in an ESD event. The intruder is usually but not necessarily charged relative to its surroundings. It is always at a potential different from that of the receptor. C62.47-92 IONIZATION CURRENT The electric current resulting from the movement of electric charges in an ionized medium, under the influence of an applied electric field. C62.1-89 & C62.11-87 IONIZATION VOLTAGE A high-frequency voltage appearing at the terminals of an arrester, generated by all sources, but particularly by ionization current within the arrester, when a power-frequency voltage is applied across the terminals.

C62.1-89 & C62.11-87 LET-THROUGH SPARKOVER A measure of the highest lightning surge an arrester is likely to withstand without sparkover in 3 µs or less. The value determined by a 1.2/50 µs impulse sparkover test: see ANSI/IEEE C62.1-84 C62.2-87 LIFETIME RATED PULSE CURRENTS (VARISTOR) Derated values of Itm for impulse durations exceeding that of an 8/20 µs wave shape, and for multiple pulses which may be applied over device's rated lifetime. C62.33-89 LIFETIME RATED PULSE CURRENTS Rated values of the peak impulse current, Ipp, as a function of the number of pulses and wave shape, which may be applied over the device rated lifetime. C62.37-96


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LIGHTNING OVERVOLTAGE The crest voltage appearing across an arrester or insulation caused by a lightning surge. C62.2-87 & C62.22-91 LIGHTNING SURGE A transient electric disturbance in an electric circuit caused by lightning.

C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 LIGHTNING An electric discharge that occurs in the atmosphere between clouds or between clouds and ground.

C62.1-89 & C62.11-87 LINE END (OF A NEUTRAL GROUNDING DEVICE) The end or terminal of the device that is connected to the line circuit directly or through another device. STD 32-90 LINE TERMINAL The conducting part provided for connecting the arrester to the circuit conductor. C62.11-87 NOTE: When a line terminal is not supplied as an integral part of the arrester, and the series gap is obtained by providing a specified air clearance between the line end of the arrester and a conductor, or arcing electrode, etc., the words line terminal used in the definition refer to the conducting part that is at line potential and that is used as the line electrode of the series gap. C62.1-89 LONGITUDINAL (COMMON) MODE VOLTAGE The voltage common to all conductors of a group as measured between that group at a given location and an arbitrary reference (usually earth). C62.31-87 LOSSES (OF A GROUNDING DEVICE) The I²R loss in the windings, core loss, dielectric loss, loss due to stray magnetic fluxes in windings and other metallic parts of the device, and, in cases involving parallel windings, losses due to circulating currents. NOTES: (1) The losses as here defined do not include any losses produced by the device in adjacent

apparatus or materials not a part of the device. (2) Losses will normally be considered at the rated thermal current but in some cases may be required at other current ratings, if more than one rating is specified, or at no load, as for grounding transformers. The losses may be given at 25 ºC or 75 ºC. STD 32-90

MAIN DISCHARGE CURRENT WAVE The relatively long portion of the ESD current wave that follows the initial current pulse, or that occurs by itself when the initial current pulse doesn't exist. It may be unidirectional or oscillatory; its initial slope may be fast or slow. C62.47-92 MAINS The ac power source available at the point of use in a facility. It consists of the set of electrical conductors (referred to by terms including "service entrance", "feeder", or "branch circuit") for delivering power to connected loads at the utilization voltage level. C62.41-91 MAIN TERMINALS The two terminals through which the principal current flows.a C62.37-96 NOTE: The main terminals may be named by application usage. In telecommunications, terminals may be named after the line connections of R(ing), T(ip), and G(round) or A, B, and C(ommon). MAIN TERMINAL 1 The main terminal that is named 1 by the device manufacturer. C62.37-96 MAIN TERMINAL 2 The main terminal that is named 2 by the device manufacturer. C62.37-96


17

MAXIMUM (HIGHEST) SYSTEM VOLTAGE The highest voltage at which a system is operated. NOTE: This is generally considered to be the maximum system voltage as prescribed in ANSI C84.1-1989 C62.1-89 & C62.11-87 & C62.22-91 The highest rms phase-to-phase voltage that occurs on the system under normal operating conditions, and the highest rms phase-to-phase voltage for which equipment and other system components are designed for satisfactory continuous operation without derating of any kind. (This voltage excludes voltage transients and temporary overvoltages caused by abnormal system conditions such as faults, load rejection, and so forth.) C62.2-87 MAXIMUM CONTINUOUS OPERATING VOLTAGE (MCOV) The maximum designated root-mean-square (rms) value of power frequency voltage that may be applied continuously between the terminals of the arrester. C62.11-87 & C62.22-91 MAXIMUM JUNCTION TEMPERATURE (TJM) The maximum value of permissible junction temperature, due to self heating, which a Thyristor SPD can withstand without degradation. C62.37-96 MAXIMUM RATING; ABSOLUTE MAXIMUM RATING A rating that establishes either a limiting capability or a limiting condition beyond which damage to the device may occur. NOTE - A limiting condition may be either a maximum or a minimum. C62.37 -96 MEANS OF GROUNDING The generic agent by which various degrees of grounding are achieved; for example, inductance grounding, resistance grounding, and resonant grounding. C62.92.1-87 MECHANICAL LIMIT The rated maximum instantaneous value of current, in amperes, that the device will withstand without mechanical failure. STD 32-90 METAL-OXIDE SURGE ARRESTER (MOSA) A surge arrester utilizing valve elements fabricated from nonlinear resistance metal-oxide materials. C62.11-87 METHODS (OR TYPES) OF GROUNDING The equipment, procedure, or scheme used for attaining the particular means. C62.92.1-87 MINIMUM IMPULSE FLASHOVER VOLTAGE The crest value of the lowest voltage impulse at a given wave shape and polarity that causes flashover. STD 32-90 MULTIPLE ESD EVENT An ESD event in which more than one discharge occurs. The time interval between successive discharges may be several microseconds to several tens of milliseconds. Related terms include multiple ESD, multiple discharge and multiple normalized peak ESD current. Ratio of peak current to charge voltage (e.g. 5a/kV). C62.47-92 NEGATIVE DIFFERENTIAL-RESISTANCE (REGION) The region of the principal voltage-current characteristic in the switching quadrant where the differential resistance is negative and the thyristor is switching between the breakdown and on-state regions. C62.37-96 NEGATIVE-BREAKDOWN RESISTANCE THYRISTOR SPD A thyristor SPD, whose static breakdown characteristic has a net negative-resistance slope prior to switching. C62.37-96 NEUTRAL GROUND CAPACITOR A neutral grounding device, the principal element of which is capacitance. STD 32-90


18

NEUTRAL GROUNDING DEVICE A grounding device used to connect the neutral point of a system of electric conductors to earth. NOTE: The device may consist of a resistance, inductance, or capacitance element, or a combination of them.

STD 32-90 NEUTRAL GROUNDING IMPEDOR A neutral grounding device comprising an assembly of at least two of the elements, resistance, inductance, or capacitance. STD 32-90 NEUTRAL GROUNDING REACTOR A neutral grounding device, the principal element of which is inductive reactance. STD 32-90 NEUTRAL GROUNDING RESISTOR A neutral grounding device, the principal element of which is resistance. STD 32-90 NEUTRAL GROUNDING WAVE TRAP A neutral grounding device comprising a combination of inductance and capacitance designed to offer a very high impedance to a specified frequency or frequencies. NOTE: The inductances used in neutral grounding wave traps should meet the same requirements as neutral grounding reactors. STD 32-90 N-GATE THYRISTOR A three-terminal thyristor in which the gate terminal is connected to the n-region adjacent to the region to which the anode is connected and that is normally switched to the on state by applying a negative signal between the gate and anode terminals. C62.37-96 NOMINAL RATE OF RISE (OF AN IMPULSE WAVE FRONT) (For a wave front,) The slope of the line that determines the virtual zero. It is usually expressed in volts or amperes per microsecond. C62.1-89 & C62.2-87 & C62.11-87 & (C62.22-91) NOMINAL SYSTEM VOLTAGE A nominal value assigned to designate a system of a given voltage class. NOTE: See ANSI C84.1-1989 C62.1-89 & C62.11-87 The system voltage by which the system may be designated, and to which certain operating characteristics of the system are related. (The nominal voltage of a system is near the voltage level at which the system normally operates and provides a per-unit base voltage for system study purposes. To allow for operating contingencies, systems generally operate at voltage levels about 5 to 10% below the maximum system voltage for which the system components are designed.) C62.2-87 & C62.22-91 NOMINAL VARISTOR VOLTAGE Voltage across the varistor measured at a specified pulsed dc current, IN(dc), of specific duration. IN(dc) is specified by the varistor manufacturer. C62.33-89 NONLINEAR EXPONENT A measure of varistor nonlinearity between two given operating currents, I1 and I2, as described by I = k V where k

is a device constant, Il < I < I2, and 12

1212 log

logVVII

=α

NON-REPETITIVE CURRENT RATING A maximum rating that may be applied to the device for a minimum of 100 times over the life of the device without failure. During the rated condition, the device is permitted to exceed its maximum rated junction temperature for short periods of time. The device is not required to block voltage or retain any gate control during or immediately following this rated condition until the device returned to the original thermal equilibrium conditions. This rated condition may be repeated after the device has returned to the original thermal equilibrium conditions. C62.37-96


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NON-REPETITIVE PEAK FORWARD CURRENT (IFSM) Rated maximum (peak) value of ac power frequency forward surge current of specified waveshape and frequency which may be applied for a specified time or number of ac cycles. C62.37-96 NON-REPETITIVE PEAK ON-STATE CURRENT (ITSM) Rated maximum (peak) value of ac power frequency on-state surge current of specified waveshape and frequency which maybe applied for a specified time or number of ac cycles. C62.37-96 NON-REPETITIVE PEAK PULSE CURRENT (IPPS) Rated maximum value of peak impulse pulse current of specified amplitude and waveshape that may be applied.

C62.37-96 NORMALIZED RISING SLOPE Ratio of the initial slope to charge voltage (e.g. 3.75 A/ns/kV). C62.47-92 OFF STATE OF A THYRISTOR SPD The state of a thyristor SPD, in a quadrant in which switching can occur, that corresponds to the high dynamic-resistance portion of the characteristic between the origin and the beginning of the breakdown region. C62.37-96 OFF-STATE CAPACITANCE (CO) The capacitance in the off-state measured at specified frequency, f, amplitude, Vd and dc bias, VD. C62.37-96 OFF-STATE CURRENT (ID) The dc value of current that results from the application of the off-state voltage, VD. C62.37-96 OFF-STATE VOLTAGE (VD) The dc voltage when the device is in the off-state. C62.37-96 OIL-IMMERSED (FOR A GROUNDING DEVICE) Means that the windings are immersed in an insulating oil. STD 32-90 OIL Includes synthetic insulating liquids as well as mineral transformer oil. STD 32-90 ON-STATE CURRENT (IT) The current through the device in the on-state condition. C62.37-96 ON-STATE (REGION) The condition of the thyristor corresponding to the low-resistance low-voltage portion of the principal voltage-current characteristic in the switching quadrants(s).a C62.37-96 ON-STATE VOLTAGE (VT) The voltage across the device in the on-state condition at a specified current IT. C62.37-96 OPERATING DUTY CYCLE One or more unit operations, as specified. C62.1-89 & C62.11-87 OSCILLATORY SURGE A surge that includes both positive and negative polarity values. C62.1-89 & C62.11-87 OUTDOOR ARRESTER An arrester that is designed for outdoor use. C62.1-89 & C62.11-87


20

OVERSHOOT DURATION (VARISTOR) The time between the point at which the wave exceeds the clamping voltage level (VC) and the point at which the voltage overshoot has decayed to 50% of its peak. For the purpose of this definition, clamping voltage is defined with an 8/20 µs current waveform of the same peak current amplitude as the waveform used for this overshoot duration. C62.33-89 OVERSHOOT DURATION The time between the point at which the wave exceeds the clamping voltage level VC and the point at which the voltage overshoot has decayed to 50% of its peak. C62.35-87 OVERVOLTAGE Abnormal voltage between two points of a system that is greater than the highest value appearing between the same two points under normal service conditions. Overvoltages may be low-frequency, temporary, and transient (surge). C62.2-87 & C62.22-91 PARAMETER A device descriptor that is measurable or quantifiable, such as a characteristic or rating. C62.37-96 PEAK FORWARD RECOVERY VOLTAGE (VFRM) The maximum value of forward conduction voltage across the device upon the application of a specified voltage rate of rise and current rate of rise following a zero or specified reverse-voltage condition. C62.37-96 PEAK GATE SWITCHING CURRENT (IGSM) The maximum value of current through the gate terminal during the transition from the off-state to the switching point, when a specified gate bias voltage, VG, is applied. PEAK NOMINAL VARISTOR VOLTAGE Voltage across the varistor measured at a specified peak ac current, IN(ac), of specific duration. IN(ac) is specified by the varistor manufacturer. C62.33-89 PEAK OFF-STATE GATE CURRENT (IGDM) The maximum gate current that results from the application of the peak off-state gate voltage, VGDM. C62.37-96 PEAK PULSE IMPULSE CURRENT (IPPM) Rated maximum value of peak impulse pulse current (IPP) applied for 10 pulses with 10 X 1000µs waveform and maximum duty factor of 0. 0l % without causing failure. C62.35-1987 [6] PERMANENTLY GROUNDED DEVICE A grounding device designed to be permanently connected to ground, either solidly or through current transformers and/or another grounding device. STD 32-90 P-GATE THYRISTOR A three-terminal thyristor in which the gate terminal is connected to the p-region adjacent to the region to which the cathode is connected and that is normally switched to the on state by applying a positive signal between the gate and cathode terminals. C62.37-96 POSITIVE-BREAKDOWN-RESISTANCE THYRISTOR SPD A thyristor SPD whose static breakdown characteristic has a net positive-resistance slope prior to switching. C62. 37-96 POWER-FREQUENCY SPARKOVER VOLTAGE The root-mean-square value of the lowest power-frequency sinusoidal voltage that will cause sparkover when applied across the terminals of an arrester. C62.1-89 & C62.11-87 POWER-FREQUENCY WITHSTAND VOLTAGE A specified root-mean-square test voltage at power frequency that will not cause a disruptive discharge. C62.1-89 & C62.11-87


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PRINCIPAL CURRENT A generic term for the current through the device excluding any gate current. NOTE - It is the current through both main terminals. C62.37-96 PRINCIPAL VOLTAGE The voltage between the main terminals.a C62.37-96 NOTES: 1 - In the case of reverse blocking and reverse conducting thyristors, the principal voltage is called positive when the anode potential is higher than the cathode potential, and called negative when the anode potential is lower than the anode potential.a 2 - For bi-directional thyristor, the principal voltage is called positive when the potential of main terminal 2 is higher than the potential of main terminal 1.a 3 - For forward-conducting thyristors the principal voltage is called positive when the cathode potential is higher than the anode potential, and called negative when the cathode potential is lower than the anode potential. PRINCIPAL VOLTAGE-CURRENT CHARACTERISTIC The function, usually represented graphically, relating the principal voltage to the principal current. Syn: principal characteristic. C62.37-96 PRORATED SECTION A complete, suitably housed part of an arrester, comprising all necessary components, including gaseous medium, in such a proportion as to accurately represent, for a particular test, the characteristics of a complete arrester. C62.1-89 & C62.11-87 PROXIMITY ESD See indirect ESD event. Also called proximity discharge. C62.47-92 QUADRANT When the principal voltage-current characteristic is expressed graphically, the voltage, v, and current, I, axes create four areas called quadrants. These quadrants are numbered counter clockwise as 1 through 4. The characteristic occurs in quadrant 1, +v and +i, and quadrant 3, -v and -i. C62.37-96 RADIO INFLUENCE VOLTAGE (RIV) A high-frequency voltage, generated by all sources of ionization current, that appears at the terminals of electric-power apparatus or on power circuits. C62.1-89 & C62.11-87 RATED AVERAGE POWER DISSIPATION Maximum average power dissipation in the device due to repetitive pulses at a specified current and temperature without causing device failure. C62.35-87 RATED CONTINUOUS CURRENT The current expressed in amperes, root mean square, that the device can carry continuously under specified service conditions without exceeding the allowable temperature rise. STD 32-90 RATED CURRENT (OF A NEUTRAL DEVICE) (CURRENT RATING) The rated thermal current of a neutral device. STD 32-90 RATED DC VOLTAGE (VARISTOR) Maximum continuous dc voltage which may be applied. C62.33-89 RATED FORWARD SURGE CURRENT Maximum single peak current for an 8.3 ms, half sine wave, without causing device failure. Applies to asymmetrical bi-directional avalanche junction surge suppressors only. C62.35-87


22

RATED FREQUENCY (OF A GROUNDING DEVICE) The frequency of the alternating current for which a device is designed. STD 32-90 RATED MULTIPLE PEAK PULSE POWER DISSIPATION IPP.PPPM = VC X IPPM Peak pulse power dissipation resulting from the pulse current. C62.35-93 RATED PEAK SINGLE PULSE TRANSIENT CURRENT (VARISTOR) Maximum peak current which may be applied for a single 8/20 µs impulse, with rated line voltage also applied, without causing device failure. C62.33-89 RATED RECURRENT PEAK VOLTAGE (VARISTOR) Maximum recurrent peak voltage which may be applied for a specified duty cycle and waveform. C62.33-89 RATED RMS VOLTAGE (VARISTOR) Maximum continuous sinusoidal rms voltage which may be applied. C62.33-89 RATED SINGLE PULSE TRANSIENT ENERGY (VARISTOR) Energy which may be dissipated for a single impulse of maximum rated current at a specified wave shape, with rated rms voltage or rated dc voltage also applied, without causing device failure. C62.33-89 RATED THERMAL CURRENT The rms neutral current in amperes which the device is rated to carry under standard operating conditions for rated time without exceeding temperature limits. STD 32-90 RATED TIME (TIME RATING) The time during which the device will carry its rated thermal current (or, for certain resistors, withstand its rated voltage) under standard operating conditions, without exceeding the limitations established by these standards. STD 32-90 RATED TIME TEMPERATURE RISE (FOR A GROUNDING DEVICE) The maximum temperature rise above ambient attained by the winding of a device as the result of the flow of rated thermal current (or, for certain resistors, the maintenance of rated voltage across the terminals) under standard operating conditions, for rated time and with a starting temperature equal to the steady-state temperature. It may be expressed as an average or a hot-spot winding rise. STD 32-90 RATED TRANSIENT AVERAGE POWER DISSIPATION (VARISTOR) Maximum average power which may be dissipated due to a group of pulses occurring within a specified isolated time period, without causing device failure. C62.33-89 RATED VOLTAGE The rms voltage, at rated frequency, which may be impressed between the terminals of the device under standard operating conditions for rated time (continuously for grounding transformers) without exceeding the limitations established by these standards. STD 32-90 RATING The designation of an operating limit for a device. C62.1-89 The nominal value of any electrical, thermal, mechanical, or environmental quantity assigned to define the operating conditions under which a component, machine, apparatus, electronic device, etc., is expected to give satisfactory service. NOTE - Rating is a generic term, but also see maximum rating. C62.37-96


23

REACTANCE GROUNDED Grounded through impedance, the principal element of which is reactance. NOTE: The reactance may be inserted either directly, in the connection to ground, or indirectly by increasing the reactance of the ground return circuit. The latter may be done by intentionally increasing the zero-sequence reactance of apparatus connected to ground, or by omitting some of the possible connections from apparatus neutrals to ground. STD 32-90 RECEPTOR ELECTRODE GEOMETRY The size and shape of that surface of the receptor, termed the receptor electrode, at which the ESD takes place. C62.47-92 RECEPTOR The body which is at rest in an ESD event. The receptor is usually but not necessarily at the same potential as its surroundings. It is always at a potential different from that of the intruder. C62.47-92 RECOVERY VOLTAGE That voltage that occurs across the terminals of a pole of circuit-interrupting device upon the interruption of the current. NOTE: For an arrester, this occurs as a result of interruption of the follow current. C62.1-89 REMOTE EARTH (POTENTIAL) The location outside the influence of local grounds, and always assumed to be at zero potential. C62.23 - 1995 REPETITIVE PEAK FORWARD CURRENT (IFRM) Rated maximum (peak) value of ac power frequency forward current of specified waveshape and frequency which may be applied continuously. C62.37-96 REPETITIVE PEAK OFF-STATE CURRENT (IDRM) The maximum (peak) value of off-state current that results from the application of the repetitive peak off-state voltage. C62.37-96 REPETITIVE PEAK OFF-STATE VOLTAGE (VDRM) Rated maximum (peak) continuous voltage that may be applied in the off-state conditions including all dc and repetitive alternating voltage components. C62.37-96 REPETITIVE PEAK ON-STATE CURRENT (ITRM) Rated maximum (peak) value of ac power frequency on-state current of specified waveshape and frequency which may be applied continuously. C62.37-96 REPETITIVE PEAK REVERSE CURRENT (IRRM) The maximum (peak) value of reverse current that results from the application of the repetitive peak reverse voltage, VRRM. C62.37-96 REPETITIVE PEAK REVERSE VOLTAGE (VRRM) Rated maximum (peak) continuous voltage that may be applied in the reverse blocking direction including all dc and repetitive alternating voltage components. C62.37-96 REPETITIVE RATING A maximum rating that may be continuously applied to the thyristor. C62.37-96 RESEAL VOLTAGE RATING OF AN ARRESTER The maximum arrester recovery voltage permitted for a specified time following one or more unit operation(s) with discharge currents of specified magnitude and duration. C62.2-87 RESISTANCE (VARISTOR) Static resistance of the varistor at a given operating point as defined by: Rx = dVx/dIx. C62.33-89


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RESISTANCE GROUNDED Grounded through impedance, the principal element of which is resistance. NOTE: The resistance may be inserted either directly, in the connection to the ground, or indirectly, as, for example, in the secondary of a transformer, the primary of which is connected between neutral and ground, or in series with the delta-connected secondary of a wye-delta grounding transformer. STD 32-90 RESISTANCE METHOD OF TEMPERATURE DETERMINATION The determination of the temperature by comparison of the resistance of a winding at the temperature to be determined, with the resistance at known temperature. STD 32-90 RESPONSE TIME (VARISTOR) The time between the point at which the wave exceeds the clamping voltage level (VC) and the peak of the voltage overshoot. For the purpose of this definition, clamping voltage is defined with a 8/20 µs current waveform of the same peak current amplitude as the waveform used for this response time. C62.33-89 RESPONSE TIME The time between the point at which the wave exceeds the clamping level (VC) and the peak of the voltage overshoot. C62.35-87 REVERSE BLOCKING QUADRANT Quadrant 3 of the principal voltage-current characteristic in which the device exhibits a reverse blocking state. C62.37-96 REVERSE DIRECTION (1) The direction of current in a p-n junction that results when the n-type semiconductor region is at a positive potential relative to the p-type region. (2) The direction of current in a semiconductor device that results when the n-type semiconductor region connected to one terminal is at a positive potential relative to the p-type region connected to the other terminal. NOTE-This definition may not apply if one or more junctions are connected in series with at least one other junction whose p and n regions are reversed. C62.37-96 REVERSE-BLOCKING DIODE THYRISTOR SPD A two-terminal thyristor SPD that exhibits a blocking state for positive cathode voltage. C62.37-96 REVERSE-BLOCKING TRIODE THYRISTOR SPD A three-terminal thyristor SPD that exhibits a blocking state for positive cathode voltage. C62.37-96 ROUTINE TESTS Tests made by the manufacturer on every device or representative samples, or on parts or materials, as required, to verify that the product meets the design specifications. C62.1-89 & C62.11-87 A test made for quality control by the manufacturer on every device, on representative samples, or on parts or materials as required to verify during production that the product meets the design specifications. STD 32-90 SAG A rms reduction in the ac voltage, at the power frequency, for durations from a half-cycle to a few seconds. C62.48-1995 SEALED TANK SYSTEM A method of oil preservation in which the interior of the tank is sealed from the atmosphere and in which the gas plus the oil volume remains constant over the temperature range. STD 32-90 SED Static Electric Discharge; an alternate name for ESD. C62.47-92


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SERIES GAP An intentional gap(s) between spaced electrodes: it is in series with the valve elements of the arrester, substantially isolating the element from line or ground, or both, under normal line-voltage conditions. C62.1-89 & C62.2-87 An intentional gap(s) between spaced electrodes in series with the valve elements across which all or part of the impressed arrester terminal voltage appears. C62.11-87 & C62.22-91 SHORT CIRCUIT An abnormal connection of relatively low impedance, whether made accidentally or intentionally, between two points of different potential in a circuit. C62.31-87 NOTE: The term is often applied to the group of phenomena that accompany a short circuit. C62.32-87 SHORT TIME RATING (OF A GROUNDING DEVICE) A rated time of ten minutes or less. STD 32-90 SHUNT GAP An intentional gap(s) between spaced electrodes that is electrically in parallel with one or more valve elements. C62.11-87 SOLIDLY GROUNDED Grounded through an adequate ground connection in which no impedance has been inserted intentionally. NOTE: Adequate as used here means suitable for the purpose intended. STD 32-90 SPARKOVER A disruptive discharge between electrodes of a measuring gap, voltage control gap, or protective device.

C62.31-87 & C62.1-89 & C62.11-87 & C62.32-87 STANDARD LIGHTNING IMPULSE The wave shape of standard impulse used (when it is not in conflict with product standards) is 1.2/50µs. C62.2-87 & C62.22-91 STANDARD SWITCHING IMPULSES The wave shapes of standard impulse tests depend on equipment being tested. C62.2-87 & C62.22-91 STARTING TEMPERATURE (FOR A GROUNDING DEVICE) The winding temperature at the start of the flow of thermal current. STD 32-90 STATIC DISSIPATIVE Having a level of resistivity that typically leads to charge dissipation. C62.47-92 STATISTICAL BIL Applicable specifically to self-restoring insulations. The crest value of a standard lightning impulse for which the insulation exhibits a 90% probability of withstand (or a 10% probability of failure) under specified conditions. C62.2-87 STATISTICAL BSL Applicable specifically to self-restoring insulations. The crest value of a standard switching impulse for which the insulation exhibits a 90% probability of withstand (or a 10% probability of failure) under specified conditions. C62.2-87 STEADY-STATE TEMPERATURE RISE (FOR A GROUNDING DEVICE) The maximum temperature rise above ambient which will be attained by the winding of a device as the result of the flow of rated continuous current under standard operating conditions. It may be expressed as an average or a hot spot winding rise. STD 32-90


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SUBASSEMBLY Subassemblies are items, not completed equipment or individual components, that have an identifiable function. C62.38-1995 SURGE (SURGE-PROTECTIVE DEVICE) A transient wave of current, potential, or power in an electric circuita. C62.11-87 & C62.22-91 NOTE: The use of this term to describe a momentary overvoltage consisting of a mere increase of the mains voltage for several cycles is deprecated. See swell. C62.41-91 & C62.1-89 & C62.2-87 & C62.37-96 A transient wave of voltage or current. The duration of surge is not tightly specified but is usually less than a few milliseconds. C62.48-1995 SURGE ARRESTER A protective device for limiting surge voltages on equipment by discharging or bypassing surge current; it prevents continued flow of follow current to ground, and is capable of repeating these functions as specified. C62.22-91 A protective device for limiting surge voltages on equipment by diverting surge current and returning the device to its original status. It is capable of repeating these functions as specified. C62.11-87 NOTE: Hereafter, the term arrester as used in this standard shall be understood to mean surge arrester.

C62.1-89 & C62.2-87 SURGE LET-THROUGH That part of the surge that passes by a surge-protective device with little or no alteration. See: surge remnant. C62.45-92 SURGE-PROTECTIVE DEVICE The generic term used to describe a device by its protective function, regardless of technology used, ratings, packaging, point of application, etc. C62.45-92 SURGE PROTECTOR (SPD) A specific complete surge-protective device, as opposed to a component of a surge protector or a generic surge-protective device. C62.42-2005 SURGE PROTECTOR A protective device, consisting of one or more surge arresters, a mounting assembly, optional fuses and short-circuiting devices, etc, which is used for limiting surge voltages on low-voltage (<1000 V rms or 1200 V dc) electrical and electronic equipment or circuits. C62.31-87 The term used to refer to a specific complete device (generally the equipment under test in the context of the present guide), as opposed to a component of the surge protector or a generic surge-protective device. C62.45-92 An assembly of protective devices consisting of one or more series, parallel, or any combination of elements used to limit surge voltages, currents, or both to a specified level. Syn: protector. C62.36-91 SURGE REMNANT That part of an applied surge that remains downstream of one or several protective devices. See: surge let-through and surge response voltage. C62.45-92 SURGE RESPONSE VOLTAGE The voltage profile appearing at the output terminals of a surge protective device and applied to downstream loads, during and after a specified impinging surge, until normal, stable conditions are reached. C62.45-92 SUSCEPTIBILITY The inability of a device, equipment, or system to resist an electromagnetic disturbance. Note: Susceptibility is the lack of immunity. C62.45-92


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SWELL A momentary increase in the power frequency voltage delivered by the mains, outside of the normal tolerances, with a duration of more than one cycle and less than a few seconds. See surge. C62.41-91 SWITCHING CURRENT (IS) The instantaneous current flowing through the device at the switching voltage, VS. C62.37-96 SWITCHING OVERVOLTAGE Any combination of switching surge(s) and temporary overvoltage(s) associated with a single switching episode.

C62.2-87 & C62.22-91 SWITCHING POINT The point in the principal voltage-current characteristic which the thyristor regenerates and initiates switching into the on-state. This point occurs at the termination of the breakdown region and the start of the negative differential-resistance region. C62.37-96 SWITCHING QUADRANT A quadrant of the principal voltage-current characteristic in which the device is intended to switch between the off-state and the on-state. For a bi-directional thyristor the switching quadrants will be 1 and 3. For a reverse blocking or reverse conducting thyristor the switching quadrant will be quadrant 1. For a forward conducting thyristor the switching quadrant will be quadrant 3. C62.37-96 SWITCHING RESISTANCE (RS)

The equivalent slope resistance of the breakdown region, RS, computed by: )(

)(

BOS

BOS

IIVV

−

−

C62.37-96 SWITCHING SURGE A heavily damped transient electrical disturbance associated with switching. System insulation flashover may precede or follow the switching in some cases but not all. C62.2-87 & C62.22-91 SWITCHING VOLTAGE (VS) The instantaneous voltage across the device at the final point in the breakdown region prior to switching into the on-state. C62.37-96 SYSTEM (CIRCUIT) VOLTAGE The root-mean-square power-frequency voltage from line to line as distinguished from the voltage from line to neutral. C62.1-89 & C62.11-87 & C62.22-91 The root mean square (rms) phase-to-phase power frequency voltage on a three-phase alternating-current electric system. C62.2-87 TAP An available connection which permits changing the active portion of the device in the circuit. STD 32-90 TEMPERATURE COEFFICIENT OF BREAKDOWN VOLTAGE

The ratio of the change in breakdown voltage, V(BR), to changes in temperature. Expressed as either millivolts per degree Celsius (mV/�C) or percent per degree Celsius (%/� C) with reference to the 25 �C value of breakdown voltage. C62.37-96


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TEMPERATURE COEFFICIENT OF BREAKDOWN VOLTAGE ( )JBRBRV dTdV /)()( =α The ratio of the change in breakdown voltage [V(BR)] to changes in temperature. Expressed as either millivolts per degree Celsius (mV/°C) or percent per degree Celsius (%/°C). C62.35-87 TEMPERATURE DERATING Derating with temperature above a specified base temperature, expressed as a percentage, such as may be applied to peak pulse current C62.37-96 TEMPERATURE DERATING Derating with temperature above specified base temperature, expressed as a percentage, such as may be applied to peak pulse power and peak pulse current. C62.35-87 TEMPORARY OVERVOLTAGE An oscillatory overvoltage associated with switching of relatively long duration, which is undamped or slightly damped. C62.2-87 An oscillatory overvoltage, associated with switching or faults (for example, load rejection, single phase faults) or from non-linearities (ferro-resonance effects, harmonics) or both, of relatively long duration, which is undamped or slightly damped. C62.22-91 TERMINALS The conducting parts provided for connecting the arrester across the insulation to be protected. C62.1-89 & C62.11-87 THERMAL CURRENT RATING For resistors whose rating is based on constant voltage, the initial rms symmetrical value of the current that will flow when rated voltage is applied. STD 32-90 THERMAL RESISTANCE Junction to ambient, case, or lead temperature rise per unit input of applied power expressed as degree Celsius per Watt. C62.35-87 THERMAL RESISTANCE (RΘJL; RΘJC; RΘJA) The effective temperature rise per unit power dissipation of a designated junction, above the temperature of a stated external reference point (lead, case, or ambient) under conditions of thermal equilibrium. C62.37-96 THERMOMETER METHOD OF TEMPERATURE DETERMINATION The determination of the temperature by mercury, alcohol, resistance, or thermocouple thermometers, any of these instruments being applied to the hottest accessible part of the device. STD 32-90 THYRISTOR A bi-stable semiconductor device comprising three or more junctions that can be switched from the off-state to the on-state or vice versa, such switching occurring within at least one quadrant of the principal voltage-current characteristic.a C62.37-96 TIME TO IMPULSE SPARKOVER The time between virtual zero of the voltage impulse causing sparkover and the point on the voltage wave at which sparkover occurs. C62.1-89 & C62.11-87 TRANSFER TIME The time duration of the transverse voltage. C62.31-87


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TRANSIENT THERMAL IMPEDANCE (ZΘJL (t); ZΘJC(t); ZΘJA(t)) The change in the difference between the virtual junction temperature and the temperature of a specified reference point or region (lead, case, or ambient) at the end of a time interval divided by the step function change in power dissipation at the beginning of the same time interval that causes the change of temperature-difference. C62.37-96 TRANSITION CURRENT The current required at a given temperature and duration to cause a current-protective device to change state. C62.36-91 TRANSITION TIME The time required for the voltage across a conducting gap to drop into the arc region after the gap initially begins to conduct. C62.31-87 TRANSVERSE (DIFFERENTIAL) MODE VOLTAGE The voltage at a given location between two conductors of a group. C62.31-87 & C62.32-87 TRAVELING WAVE The resulting wave when an electrical variation in a circuit such as a transmission line takes the form of translation of energy along a conductor, such energy being always equally divided between current and potential forms. C62.2-87 & C62.22-87 TRIBOELECTRIC CHARGING The generation of electrostatic charges when two pieces of material are brought into intimate contact and are then separated. Also termed triboelectrification. C62.47-92 TRIBOELECTRIC SERIES A list of substances in an order of relative positive to negative charging as a result of the triboelectric charging effect. C62.47-92 UNGROUNDED Without an intentional connection to ground except through potential indicating of measuring devices or other very-high-impedance devices. STD 32-90 UNIDIRECTIONAL THYRISTOR SPD A thyristor SPD that has switching characteristics in only quadrant. NOTE-The main unidirectional thyristor SPDs are the reverse-blocking, reverse conducting and forward conducting thyristor SPDs. C62.37-96 UNINHIBITED OIL Mineral transformer oil to which no synthetic oxidation inhibitor has been added. STD 32-90 UNIT OPERATION Discharging a surge through an arrester while the arrester is energized.

C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 VALVE ARRESTER An arrester that includes a valve elements. C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 VALVE ELEMENT A resistor that, because of its nonlinear current-voltage characteristic, limits the voltage across the arrester terminals during the flow of discharge current and contributes to the limitation of follow current at normal power frequency voltage. C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 VARIATION OF HOLDING CURRENT WITH TEMPERATURE The change in holding current, IH, with changes in temperature. It is shown as a graph. C62.37-96


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VARISTOR VOLTAGE Voltage across the varistor measured at a given current, IX. C62.33-89 VENT An intentional opening for the escape of gases to the outside. C62.1-89 & C62.11-87 VIRTUAL DURATION OF WAVE FRONT (OF AN IMPULSE) The virtual value for the duration of the wave front is as follows: For voltage waves with wave front duration less than 30 �s, either full or chopped on the front, crest, or tail, 1.67 times the time for the voltage to increase from 30% to 90% of its crest value. a

(2) For voltage waves with wave front duration of 30 �s or more, the time taken by the voltage to increase from actual zero to maximum crest value. a (3) For current waves, 1.25 times the time for the current to increase from 10% to 90% of crest value. a C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 & C62.37-96 (VIRTUAL) JUNCTION TEMPERATURE (TJ) A theoretical temperature representing the temperature of the junction(s) calculated on the basis of a simplified model of the thermal and electrical behavior of the device. C62.37-96 VIRTUAL ZERO POINT (OF AN IMPULSE) The intersection with the zero axis of a straight line drawn through points on the front of the current wave at 10% and 90% crest value, or through points on the front of the voltage wave at 30% and 90% crest value.

C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 & C62.37-96 VOLTAGE CLAMPING RATIO (VARISTOR) A figure of merit measure of the varistor clamping effectiveness as defined by the symbols VC/Vm(ac), VC/Vm(dc). C62.33-89 VOLTAGE CLAMPING RATIO A figure of merit, which determines the clamping effectiveness of an avalanche surge suppressor as defined by the symbols. C62.35-87 VOLTAGE OVERSHOOT (VARISTOR) The excess voltage above the clamping voltage of the device for a given current that occurs when current waves of less than 8 �s virtual front duration are applied. This value may be expressed as a % of the clamping voltage (VC) for an 8/20 �s current wave. C62.33-89 VOLTAGE OVERSHOOT The excess voltage above the clamping voltage (VC) of the device for a given current that occurs when current waves of less than 10 �s virtual front duration are applied. This value may be expressed as a percentage of the clamping voltage (VC) for a 10 X 1000 �s current wave. C62.35-87 VOLTAGE RATING The designated maximum permissible operating voltage between its terminals at which an arrester is designed to perform its duty cycle. It is the voltage rating specified on the nameplate. C62.1-89 VOLTAGE TO GROUND The voltage between any live conductor of a circuit and the earth. NOTE: Where safety considerations are involved, the voltage to ground that may occur in an ungrounded circuit is usually the highest voltage normally existing between the conductors of the circuit, but in special circumstances higher voltages may occur. STD 32-90 VULNERABILITY The characteristic of a device for being damaged by an external influence, such as a surge. C62.45-92


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WAVEFORM A manifestation or representation (that is, graph, plot, oscilloscope presentation, equation(s), table of co-ordinate or statistical data, etcetera) or a visualization of a wave, pulse or transition.a C62.37-96 WAVEFRONT (OF A SURGE OR IMPULSE) That part (of an impulse) which occurs prior to the crest value.a C62.1-89 & C62.11-87 & C62.22-91 & C62.37-96 WAVE SHAPE (OF AN IMPULSE TEST WAVE) The graph of the wave as a function of time.a C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 & C62.37-96 WAVE SHAPE DESIGNATION (OF AN IMPULSE) The wave shape of an impulse (other than rectangular) of a current or voltage as designated by a combination of two numbers. The first, an index of the wave front, is the virtual duration of the wave front in microseconds. The second, an index of the wave tail, is the time in microseconds from virtual zero to the instant at which one-half of the crest value is reached on the wave tail. Examples are 1.2/50 and 8/20 waves.

C62.1-89 & C62.2-87 & C62.11-87 & C62.37-96 The wave shape of a rectangular impulse of current or voltage is designated by two numbers. The first designates the minimum value of current or voltage that is sustained for the time in microseconds designated by the second number. An example is the 75A X 1000 µs wave. C62.2-87 & C62.22-91 & C62.37-96 WAVE SHAPE OF A RECTANGULAR IMPULSE OF CURRENT OR VOLTAGE This wave is designated by two numbers. The first designates the minimum value of current or voltage which is sustained for the time in microseconds designated by the second number. An example is the 75A X l000 µs wave. C62.1-89 WAVE TAIL (OF AN IMPULSE) That part between the crest value and the end of the impulse.a

C62.1-89 & C62.2-87 & C62.11-87 & C62.22-91 & C62.37-96 WAVE The variation with time of current, potential, or power at any point in an electric circuit. a

C62.1-89 & C62.11-87 & C62.37-96 WITHSTAND VOLTAGES The voltage that electric equipment is capable of withstanding without failure or disruptive discharge when tested under specified conditions; see ANSI C92.1-82 & C62.2-87 & C62.22-91

Documents

IEEE / PESpes-spdc.org/system/files/filedepot/21/C62DEF-May06.pdf · C62.92.2 17. C62.92.4 18. C62.92.5 19. IEEE STD 32-1990 Surge Protective Devices Committee C62 Definitions 2 AC