Protections From RET670

8/14/2019 Protections From RET670

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Protections from RET670

Frequency protection

SAPTUF- Underfrequency protection

>Underfrequency protection SAPTUF is used to detect low power system frequency.

SAPTUF can either have a definite time delay or a voltage magnitude dependent

time delay. If the voltage magnitude dependent time delay is applied, the time

delay will be longer if the voltage is higher, and the delay will be shorter if the

voltage is lower. If the frequency remains below the set value for a time period

corresponding to the chosen time delay, the corresponding trip signal is issued. it

has restore function also and no need CB status work with under voltage block.

Inputs are voltage and block , outputs are start, trip, restore, block and fre(real).

SAPTOF- Overfrequency protection

>Overfrequency protection SAPTOF is used to detect high power system frequency.

SAPTOF has a settable definite time delay. If the frequency remains above the set

value for a time period corresponding to the chosen time delay, the corresponding

TRIP signal is issued. It has UV setting to block the function .

SAPFRC- Rate-of-change frequency protection

>SAPFRC is provided with an undervoltage blocking. Rate-of-change frequency

protection (SAPFRC) can be partially or totally blocked, by binary input signals orby parameter settings. When the frequency has returned back to the setting of

RestoreFreq, the RESTORE output is issued after the time delay tRestore.

Voltage protection

UV2PTUV- Two step undervoltage protection

>UV2PTUV has two voltage measuring steps with separate time delays.

UV2PTUV can be set to measure phase-to-earth fundamental value, phase-to-phasefundamental value, phase-to-earth true RMS value or phase-to-phase true RMS

value.

NO CB status block, only voltage controlled block.

OV2PTOV- Two step overvoltage protection

>similar like UV2PTUV


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ROV2PTOV- Two step residual overvoltage protection

>The residual voltage

can be measured directly from a voltage transformer in the neutral of a power

transformer or from a three-phase voltage transformer, where the secondary

windings are connected in an open delta. Another possibility is to measure thethreephase

voltages and internally in the IED calculate the corresponding residual

voltage and connect this calculated residual voltage to ROV2PTOV.

It not has any voltage controlled blocking.

OEXPVPH- Overexcitation protection

>E = 4.44 f n Bmax AFn Block need voltage and current as a n input and has outputs as trip and start signals.Time delay has two option as curve ( IEEE, tailoyer).There is voltage controlled block with fixed setting.

VDCPTOV-Voltage differential protection

>The Voltage differential protection function VDCPTOV (60) is based on

comparison of the amplitudes of the two voltages connected in each phase. There is a

voltage controlled block. Fn block needs 2 input voltages and outputs will be start,

trip, alarm and Udiff mag (real).

LOVPTUV-Loss of voltage check

>Loss of voltage check (LOVPTUV) is suitable for use in networks with an

automatic system restoration function. LOVPTUV issues a three-pole trip command to

the circuit breaker, if all three phase voltages fall below the set value

for a time longer than the set time and the circuit breaker remains closed.

Fn will be blocked if VTFF, CB open and voltage controlled block.

It has restore option also.

Current protection

NS2PTOC-Negativ sequence time overcurrent protection for machines

>NS2PTOC sets the START, ST1 or ST2 outputs active and starts to count trip time

only when the measured negative sequence current value rises above the set value of

parameters I2-1> or I2-2> respectively.


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CBPGAPC-Capacitor bank protection

>Shunt Capacitor Banks (SCB) are used in a power system to provide reactivepower compensation and power factor correction.

Capacitor bank protection (CBPGAPC) function measures the SCB three-phasecurrent. CBPGAPC function has the following built-in features:

Overcurrent stage

Undercurrent stage

Reconnection inhibit

Harmonic overload

Reactive power overload

From the measured SCB currents, voltage value across every SCB phase is

calculated.

It has reconnection inhibit feature.

Need current as an input and output will be start, trip signals.

BRCPTOC- Broken conductor check

>The current asymmetry signal output START is set on if:

The difference in currents between the phase with the lowest current and the

phase with the highest current is greater than set percentage Iub> of the

highest phase current

The highest phase current is greater than the minimum setting value IP>.

The lowest phase current is below 50% of the minimum setting value IP

GOPPDOP- Directional overpowerprotection

>The calculated power component is compared to the power pick up setting

Power1(2). A start signal START1(2) is activated if the calculated power

component is larger than the pick up value. After a set time delay TripDelay1(2) a

trip TRIP1(2) signal is activated if the start signal is still active. At activation

of any of the two stages a common signal START will be activated. At trip from any

of the two stages also a common signal TRIP will be activated.

GUPPDUP- Directional underpower protection

>similar to GOPPDOP


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CCRPLD- Pole discordance protection

>If the pole discordance protection is enabled, then two different criteria can

generate a trip signal TRIP:

Pole discordance signaling from the circuit breaker.

Unsymmetrical current detection.

From external signal also.

AR can block this protection.

The current based pole discordance function can be

set to be active either continuously or only directly in connection to breaker open

or close command.

CCRBRF-Breaker failure protection

>Breaker failure protection CCRBRF is initiated from protection trip command,either from protection functions within the IED or from external protection devices.

It has 2 stage backup trip, 2 stage retrip and alarm. Need current , BF initiation

and CB status. It has three detection logic I, 52A, I&52A.

External BF signal can issue backup trip without conditions directly.

TRPTTR-Thermal overload protection, two time constants

>If this calculated relative temperature is larger than the relative temperature

level corresponding to the set operate (trip) current a start output signal START isactivated.

If cooling input signal active Ibase2 activated.

By activating enable multiple setting maybe increased.

LPTTR-Thermal overload protection, one time constant

>If temperature is larger than the set operate temperature level, TripTemp, a START

output signal is activated. When the component temperature reaches the set alarm

level AlarmTemp the output signal ALARM is set. When the component temperature

reaches the set trip level TripTemp the output signal TRIP is set.

It has current multiplier and ambient temp input feature.

SDEPSDE- Sensitive directional residual overcurrent and powerprotection

>The function is using phasors of the residual current and voltage.


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Directional residual current protection measuring 3I0cos

-For trip, both the residual current 3I0cos and the release voltage 3U0, must belarger than the set levels:Directional residual power protection measuring 3I0 3U0 cos

-For trip, both the residual power 3I0 3U0 cos , the residual current 3I0 and

the release voltage 3U0, shall be larger than the set levelsDirectional residual current protection measuring 3I0 and

-For trip, both the residual current 3I0 and the release voltage 3U0, shall be

larger than the set levels and the angle shall be in the set sector.

Non-directional earth fault current protection

-For trip, the residual current 3I0 shall be larger than the set levels

Residual overvoltage release and protection

-For trip, the residual voltage 3U0 shall be larger than the set levels

NS4PTOC- Four step directional negative phase sequenceOver current protection>Four step negative sequence overcurrent protection NS4PTOC function has the

following three Analog Inputson its function block in the configuration tool:

1. I3P, input used for Operating Quantity.

2. U3P, input used for Voltage Polarizing Quantity.

3. I3PPOL, input used for Polarizing Quantity.

NS4PTOC function can be set

to use voltage polarizing or dual polarizing. It has current multiplier option.

EF4PTOC

- Four step residual overcurrentprotection>The directional function includes 3 optionsvoltage polarized

current polarized

dual polarized

Second harmonic blocking can be set individually for each step.

This function has the following three Analog Inputson its function block in the

configuration tool:

1. I3P, input used for Operating Quantity.

2. U3P, input used for Voltage Polarizing Quantity.

3. I3PPOL, input used for Current Polarizing Quantity.

The protection is internally divided into the following parts:

1. Four residual overcurrent steps.

2. Directional supervision element for residual overcurrent steps with integrated

directional comparison step for communication based earth-fault protection

schemes (permissive or blocking).

3. Second harmonic blocking element with additional feature for sealed-in


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blocking during switching of parallel transformers.

4. Switch on to fault feature with integrated Under-Time logic for detection of

breaker problems during breaker opening or closing sequence.

Need CB pos and cmd signals for SOTF fn.

EFPIOC-Instantaneous residual overcurrent protection>EFPIOC can be configured to measure the residual current from the three-phase

current inputs or the current from a separate current input.

It has current multiplier and AR can block the protection.

OC4PTOC-Four step phase overcurrent protection

>The protection design can be decomposed in four parts:The direction element

The harmonic Restraint Blocking function

The four step over current function

The mode selection

PHPIOC-Instantaneous phase overcurrent protection

>If a phase current is larger than the set operation current a signal from thecomparator for this phase is set to true.

This signal will, without delay, activate the output signal.

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Protections From RET670