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PROTECTION AT THE SPEED OF LIGHT: ARC-FLASH PROTECTION COMBINING ARC FLASH SENSING AND ARC-RESISTANT TECHNOLOGIES

Copyright Material IEEE Paper No. PCIC-2009-

John A. Kay, CET Juha Arvola Lauri Kumpulainen Senior Member, IEEE Member, IEEE Member, IEEE Rockwell Automation Canada VAMP VAMP 135 Dundas St. 65101 Yrittajankatu 15 65101 Yrittajankatu 15 Cambridge, ON, N1R 5X1 Vaasa, 65380 Vaasa, 65380 Canada Finland Finland

jakay@ra.rockwell.com Juha.Arvola@vamp.fi Lauri.Kumpulainen@vamp.fi

Abstract - One of the most critical aspects of reducing both personnel injury and equipment damage is through the reduction of the energy available to an arcing fault. The initiation of a trip and the clearing time (opening) of any upstream device is a critical component in the reduction of the resultant arc flash incident energy. Combining technologies that detect and interrogate both arc flash and the associated arc current signatures in combination with arc resistant switchgear or controlgear, can provide a coordinated solution for controlling the level of incident energy at various points within the distribution network. Hybrid systems of this type provide the highest level of personnel protection, along with comprehensive equipment protection, as detection and initiation of tripping is implemented faster than with conventional relaying techniques alone. The reduction of the overall trip time can reduce equipment collateral damage, reconditioning time and lost productivity resulting from downtime. These types of coordinated systems will also lower the personal protective equipment (PPE) requirements based on incident energy. This paper compares several systems including conventional overcurrent protection, zone selective and various light and current sensing systems.

Index Terms — arc faults, arc flash, arc resistant equipment,

arc sensors, controlgear, optical arc detection, switchgear

I. INTRODUCTION

It is well documented that arcing faults cause both personnel hazards and significant economic losses due to damage to equipment and interruption of processes. The awareness of these risks has risen recently and several methods to mitigate the consequences of arc-flash incidents have been introduced. This paper summarizes the characteristics and consequences of electric arcing faults, compares different protection methods including arc resistant control equipment and introduces a fast, selective arc-flash mitigation technology.

The incident energy of an arc-flash depends on associated voltage, current, and arcing time. The system voltage is normally not adjustable in regards to reduction or eliminating arc-flash. On the other hand, the fault duration or arcing time can be restricted in various ways.

System impedance can be increased by selection of transformers and through the use of current limiting reactors. Two of the drawbacks of increasing the system impedance is

the increased equipment cost and increased system losses. A. Arcing Faults Characteristics

Most arc-flash faults start as single phase to ground faults

and develop into three phase faults. This emphasizes the importance of early detection of the arc in order to rapidly clear the fault.

The majority of arcing faults in switchgear and controlgear are caused by human error. Examples of this are, entering into a live panel or the careless or improper use of tools. Equipment related arc faults can be caused by loose connections, insufficient mechanical/electrical dimensioning, equipment malfunction, degradation of wire or cable insulation due to improper installation practices, vermin contamination or other contaminants.

Arcing faults release large amounts of energy in the form of radiant heat, intense light, and high pressure waves. The temperature of the plasma escalates rapidly to temperatures as high as 35,000 0F (19,500 0C). This rapid increase of temperature expands the volume of the air causing a huge pressure wave. Components can change their physical state from solid to vapor virtually instantaneously. The expansion rate of the ‘fuel’ to the arc, e.g. copper, expands by a factor of 67,000 times in vaporization. This expansion component significantly increases the pressure within a cabinet or enclosure. Other dangers associated with the arc blast include the release of light and heat radiation, a heat and pressure wave, shrapnel and toxic gases all causing additional personnel hazard [1], [2].

Arcing fault currents are not the same as bolted fault currents because of the varying resistance within the arc. Because an electric arc is unpredictable, exact values for an arc’s resistance and resultant current level cannot be given. The formulas and calculations outlined in the IEEE 1584 standard were developed to determine estimated incident energy levels at various points in the distribution network and are based on experimental data [15]. These results do confirm that the arcing current is always lower than bolted fault current [3], [4]. This is especially true in the case of low voltage, where the arcing current can be less than half the value of the bolted fault current. It is very important to note that the lower fault currents associated with some arcing faults may lead to longer fault clearing times and thus to higher incident energy levels [16].

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B. Hazards and Damage Associated with Arc Faults

Even with recent enhanced focus on electrical safety, it is clear the risk to personnel related to arc flash incidents is still quite high with an estimated 2000 serious arc flash burns to workers each year in the United States alone [5]. Depending on the arc fault current level and the amount of time the arc is sustained, significant damage to the equipment will occur. This could include total destruction of the enclosure or internal devices. As well, the released incident energy, defined as the amount of energy impressed on a surface at a certain distance from the source, is generated as a result of the arc event. There are four factors that determine the incident energy: distance, voltage, current and arcing time [1]. Since the voltage is considered as a system issue, the evaluation of the protection methods in the next section will be focused on the other factors.

C. General Arc Fault Protection Methods

As outlined earlier in this paper, human error is still the most

common cause of arc flash accidents. Even with advanced education, instructions and more stringent working procedures, errors still can be made. In addition to these factors, a more proactive technical approach aims at reducing the exposure to arc flash by utilizing a combination of arc resistant control products and advanced systems which monitor the optical and current signatures associated with an arc fault event. There are other single element methods and systems which incorporate on-line monitoring.

On-line monitoring of partial discharges, especially in cable compartments, has not yet been widely implemented. Infrared and ultraviolet detection systems can also be considered for on-line monitoring of switchgear and control gear. These on-line systems monitor electrical equipment with the intent of reducing the number of faults caused by failure of equipment. But these systems still can not prevent arc flash incidents caused by human errors. On-line analyzing of arcing fault currents has been proposed for preventive arc fault detection in several technical papers [6], [7]. The focus in these investigations has been the question of whether the changes in harmonic spectrum could be the basis for preventive arc detection.

Some developing faults may be detected in their early stages, by using smoke or infrared detectors. When these types of detectors are connected to protection relays, it may be possible to totally prevent arcing and avoid major damage preemptively.

The system grounding method has a direct influence on the magnitude of ground fault current. Because most arc flash faults initiate as single phase to ground faults, systems with low ground-fault current reduce the probability of serious arc flash incidents. Some researchers recommend high resistance grounding for low voltage systems for safety reasons [8]. High resistance grounded systems, where a resistance is placed between the neutral point and the ground, have been applied mainly in low voltage systems. In the event of a phase to phase fault, there is no difference between solidly grounded and high resistance grounded systems.

The use of bus differential protection is a relatively fast method (typical clearing times of 5-10 cycles, 80-160ms with some breakers) for bus protection. The inclusion of high impedance bus differential protection does add significant costs

to the distribution system. This type of system requires specific and dedicated current transformers and the associated extra wiring. Differential relays measure the difference in current between a pair of associated current transformers. If the current differential between the two current transformers is above the pickup value in the relay, the relay initiates a trip.

Low impedance bus differential schemes may not require dedicated current transformers, but the setup of the relays is much more complex than in high impedance bus differential schemes. Neither of these differential schemes provides protection against faults in the feeder (incoming) cable compartments. This has been documented as the most probable location for an arc fault in normal operating condition, i.e. in a closed door situation without operator intervention [13, 17].

D. Mechanical Arc Fault Protection Methods

Arc resistant equipment typically provides a mechanical

barrier between the operator and the arc fault and these systems redirect the energy of the arc blast away from the operator. From a safety point of view, arc-resistant equipment provides protection to personnel as long as the doors are closed. This stipulation is included as part of the relative global testing guidelines. Arc resistant control equipment must be tested to one of these guides, (Fig. 1). However, opening a low voltage door is a very common practice [11].

Fig. 1 Arc resistant controller under arc test

Some manufacturers have incorporated hybrid designs which

protect those working in the low voltage compartments of arc resistant medium voltage (MV) controllers with the low voltage door open [9]. The MV controllers may or may not necessarily survive the internal fault, meaning the unit may not be repairable depending on the magnitude and duration of the arc fault [10]. This could mean that a long equipment outage could be expected after an arc fault event if the fault is not controlled.

E. Current Limiting Fuses

One of the best known technologies used in arc current

limiting is current limiting fuses. When the current is high enough, current limiting fuses extinguish their internal arc

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before the zero of the current is reached. This shortens the duration of the arc and reduces the arc energy. Current limiting fuses provide current limiting action only in cases of very high fault current [10]. When current limiting fuses do not operate in their current limiting range, clearing times can be significantly longer [1]. In fact, lower currents can lead to higher incident energy levels and the possible failure of the fuse to clear properly, resulting in fuse failure or rupture. If the fuse does rupture, the resultant cloud of arc byproducts could initiate an additional arc fault.

When arc flash fault risk analysis are conducted, both the highest possible and the lowest possible fault currents should be considered in the analysis. The risks associated with high fault currents are obvious, but low level fault currents can be very challenging. These low level fault currents can lead to extended operating times for protective relays or even cause damage to fuses. In low voltage (LV) systems, the arcing current can easily be less than half of the bolted fault current. Factors like these need to be considered in the final analysis of a coordinated protection system. The limitations of current limiting fuses under low level fault current conditions, is also well documented [12].

The use of high speed relaying is one way of reducing the incident energy levels. However, when the speeding up of normal protection by reducing operation times is normally not sufficient, dedicated protection is needed. There are several methods for decreasing the arcing time.

F. Zone Selective Interlocking

Trip initiation times of 3-10 cycles can be reached by zone selective interlocking, thus leading to total clearing times of approximately 10 cycles. This method requires communication between the relay of the main circuit breaker and the feeder relays. If the downstream relay picks up, it sends a blocking signal to the relay of the upstream breaker. If the downstream relay does not see the fault, the relay of the main circuit breaker does not receive a blocking signal and the main breaker can be opened almost instantaneously.

Fig. 2 The principle of zone selective interlocking

The latest substation communication standard, IEC 61850, provides horizontal relay to relay messaging in the form of Generic Object Oriented Substation Events, (GOOSE). This type of messaging is used for protection functions and other applications requiring high speed multicast peer-to-peer communications capabilities. This method has been suggested for sending interlocking signals instead of using conventional hard wiring.

G. Maintenance Switch/Instantaneous Settings

Decreased incident energy levels may be achieved by

placing the upstream breakers into an instantaneous tripping mode by means of introducing a maintenance switch that enables instantaneous tripping during maintenance work. This scheme can be incorporated on both medium voltage and low voltage systems. It can be implemented using some existing microprocessor based protective relays, provided that the relays used contain multiple setting groups or multiple instantaneous overcurrent stages. Although the initial cost for this method may be lower than a differential system, the drawback is the sacrifice of system coordination which could result in non-selective tripping.

The activation and deactivation of this type of system typically requires operator intervention which in turn increases the risk of human error. Although this protection scheme can reduce the incident energy level for a specific breaker, many substation schemes are fed from multiple points and may not permit decreasing the tripping points for multiple breakers simultaneously. As well, from an asset protection point of view, this method is effective only during maintenance work. There must also be coordination with all operations groups to ensure that another functional group does not initiate a start of any motors when the maintenance switch is initiated.

H. Optical Arc Flash Sensing

An arcing fault does instantaneously produce light and heat radiation that can be detected by analyzing the visible light spectrum. Optical sensor based arc flash protection can provide very short fault clearing time. However, overcurrent signature detection should be combined with the detection of the visible light (dual sensing) to avoid false tripping. Since a majority of arcing faults start as single phase faults, it is essential to analyze the neutral current signature as well. With neutral current measurement, it is possible to clear the fault in its early stages before a fault escalates to a phase to phase fault [16]. For the most selective arc flash protective system, the system should provide separate setting levels for phase to ground and phase to phase faults.

The operation of electronic arc flash protection should be based on simultaneous light and phase overcurrent or ground overcurrent conditions. Because of the light condition being basically a binary function, the overcurrent settings can be very sensitive. For special purposes, a ‘light only’ condition can also be used [14].

The tripping of an upstream breaker or contactor is initiated by a dedicated arc flash protection relay or by a common numerical motor or feeder protection relay equipped with arc flash protection capabilities. The trip will be initiated within a few milliseconds. If a semiconductor output is used instead of a

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conventional mechanical trip relay, a trip initiation time of 1-2ms is possible.

Fig. 3 below shows the results in a switchgear power cell exposed to a 50kA arc fault for 500ms arcing time. Fig. 4 shows the result of a similar 50kA arc fault where a light and current based arc flash protection system resulted in a total fault arcing time of less than four cycles. These photographs dramatically illustrate the importance of the reduction of the arcing time which mitigates damage to the equipment.

Fig. 3 Results from a 50kA arc fault with a 500ms arcing time

Fig. 4 Test result with light and current based protection with

total clearing time of less than four cycles Incident energy comparison verifies the importance in the

speed of the protection. Fig. 5 illustrates the impact of arcing time on incident energy by comparing different protection

methods. Fig. 5 also illustrates the comparison of incident energy between conventional overcurrent protection, zone selective interlocking, light and current based detection and light and current detection with the inclusion of an arc quencher or eliminator. The data shows significant reductions in incident energy levels between protection methods. The incident energy levels have been calculated according to standard IEEE STD 1584-2002 [15].

Comparison of incident energy

Breaker time 50ms

0,00

5,00

10,00

15,00

20,00

25,00

30,00

35,00

Conventionalovercurrentprotection

(400ms+50ms)

Zone selectiveinterlocking

(100ms+50ms)

Light & currentbased detection

(7ms+50ms)

Light & currentdetection andarc eliminator

(2ms)

Ener

gy /

cal/c

m^2

Fig. 5 Comparison of incident energy (480 V, 65kA, bus gap

32 mm, working distance 610 mm, grounded)

I. Dedicated Optical Sensor Based Protection Arc flash protection is usually implemented by using

separate systems utilizing arc flash detectors connected to dedicated arc protection relays. Traditional overcurrent and ground fault protection is carried out by other relays. A comprehensive, selective arc flash protection system comprises of arc flash sensors, I/O units collecting data from the sensors or current transformers, and a master unit or several units for final collection. These units display all of the sensor data, the measured currents and can initiate the tripping of a contactor or breaker if both light and overcurrent are detected. Correct operation should be ensured in all network topologies by measuring the current from all possible feeding directions, including emergency incoming feeders. These measurements are performed by master units or slave units dedicated for current measurement.

Setting of optical sensor based arc flash protection is very straightforward. Light detectors are factory set to react on specific arc light signatures and do not require field settings by the user. The phase overcurrent protection is set above the highest possible load current with low margin as simultaneous arc light activation is required for initiation of a trip condition. The ground overcurrent settings can remain very sensitive. The light condition requirement provides security, while on the other hand sensitive settings enable early detection of other faults. Motor starting currents may be neglected as tripping action requires simultaneous light condition.

In multi-zone arrangements, master units and I/O units must be able to exchange data between each other. Information from

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an activated sensor can be distributed to all units. Similarly, information on locally detected overcurrent conditions can be passed to other units as a trip condition. The information on overcurrent and the information on arc-flash light, including location, can then be combined to produce a selective trip.

J. Optical Sensor Types

Optical arc flash sensors (Figs. 6, 7, 8) can be point sensors or fiber optic loop type sensors. The selection of the type of sensor depends on the application. Practical experience has shown that long fiber optic loops should be avoided on long lineups of controllers as it makes installation more challenging. Long fiber optic cable runs can be easily broken during transportation and installation of the gear. Depending on the location within the switchgear or controlgear, they may be difficult to replace or recondition. If an arc fault occurs, the fiber loop may be damaged and would need to be replaced or reconditioned.

Ideally, looped fiber optics should be divided into short loops based on a per cabinet basis. Fiber optic sensor loops may be cost effective to apply for low voltage switchgear or low voltage motor control centers (MCC) with multiple compartments.

New single point sensor technology has many advantages including ease of installation and its adaptability to retrofit installations. The point sensor system provides for exact fault location indication since these types of sensors can be installed in individual compartments providing compartmental detection and protection, (Fig. 8).

Fig. 6 Common Point Sensor and Fiber Optic Loop Sensor

By utilizing mobile personal point sensor technology attached

to the clothing of personnel working around electrical equipment, the safety of the personnel can be greatly enhanced even further, (Fig. 7). These portable arc flash sensors provide

a level of personal safety while working near live voltage. The portable sensor is connected to the nearest protection device incorporating arc flash detection capabilities.

Fig. 7 Portable Personal Point Sensor

Regardless of the sensor type used, it is essential that the arc

flash protection system include a complete and continuous self-supervision function which includes the sensors and cables. Because of continuous self-supervision of the system and components, periodic inspection interval of several years is considered adequate.

Commissioning verification of light and current based protection is quite simple. Secondary current can be injected or simulated while the light sensors are activated by an appropriate high efficiency light source or camera flash. You should always follow the directions and specifications from the manufacturer regarding the light source requirements.

Fig. 8 Point Sensor in a Cable Compartment

K. Microprocessor Based Relay Protection

There are now available microprocessor based protection relays that can be equipped with arc flash protection capabilities. In practical terms, this means sensor inputs to which the arc flash sensors can directly be connected. This way the total cost of the protection concept is minimal.

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The protection device may include multiple configurations for arc sensor input, (Fig. 9). This may include inputs for optical arc sensors, binary inputs and outputs for sending and receiving arc sensor data to other relays within a protection system. All relays with arc flash protection capabilities should include high speed overcurrent and ground fault protection stages dedicated to operation with the arc flash sensors.

Fig. 9 Protection using common numerical relays equipped

with arc flash protection option

The selectivity of arc flash protection can be increased by connecting arc flash sensors on the outgoing feeder to the overcurrent relay of the feeder. If an arc fault occurs in the feeder area, only the feeder breaker will open leaving the rest of the substation operational. This is very beneficial since many arc faults occur in cable compartments. Fig. 9 presents an example of arc flash protection carried out by common numerical relays including an arc flash protection option.

L. Ultra-Fast Arc Flash Protection

With light and current based arc flash protection, the arcing

time consists of the operation time of the protection relay (2-15ms) and the operation time of a circuit breaker or contactor (typically 50-80ms). There are technologies now available which can provide extremely short arc clearing times. The shorter the arcing time, the lower the peak rise of the associated pressures and the damage. The use of arc quenching devices can reduce the arcing times to as little as 2-5ms.

When the arc is detected by this type of arc protection system, the trigger devices initiate a signal to the quenching device in 2-5ms. The quenching device creates a controlled short circuit at ultra high speed, resulting in a low impedance path for the current. Fig. 10 illustrates a typical re-settable medium voltage arc quenching device.

The bolted short circuit current flows through the quenching device until the circuit breaker opens or the fuses break the current. A combination of an arc quenching device with current

limiting fuses is a potential solution to overcome the limitations of current limiting fuses described in [12].

Fig. 10 Reusable MV Arc Quenching Device

In low voltage system applications, a quenching device can

remove an arc fault within 2ms. Arc quenchers used within medium voltage systems are able to extinguish an arc fault within 5ms.

M. Practical Use Of Dedicated Optical Arc Sensor Technology

Optical arc flash protection has and continues to be a de

facto standard in several countries around the world. This type of technology has evolved significantly over the past 20 years since its original introduction. There are now thousands of these types of installations worldwide – mostly outside of North America. In the regions of Europe and in Africa, light/current based protection significantly mitigates arc flash incidents every year. This technology is applied by a wide variety of global industries including electric utilities, forest products, steel factories, power generation plants, oil and gas, mining, marine applications and even in wind based power generation plants.

II. CONCLUSION

In this paper we have outlined various methods to mitigate

arc flash hazard by using arc resistant controls, optical or combined current and optical sensing. When selecting an arc flash protection method, speed and reduction of incident energy are the most important but not the only criteria. Analyzing different methods beyond existing workplace safety standards is needed. Asset protection, along with the protection reliability and selectivity should be taken into account as in any protective system design. Early detection of an arc flash should be emphasized. The combination of the sensing of light and a specific overcurrent signature can prove to be a very efficient method of reducing arc fault energy. This method can be applied by a dedicated arc flash protection systems or by using common numerical protection relays equipped with an arc flash protection option. For the most demanding cases, ultra-fast arc eliminating technology is now available. When used in combination with arc resistant control products, a coordinated hybrid arc protection solution can be achieved.

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III. REFERENCES

[1] Dugan, T., “Reducing the Arc Flash Hazard”, IEEE Industry Applications Magazine, p. 51-58, May/June 2007

[2] Lee, R.H., “Pressures Developed by Arcs”, IEEE Transactions on Industry Applications, Vol. IA-23, p. 760-763, July 1987

[3] Murphy, M. “How to form a bounding arc flash study for your site”, IEEE IAS Electrical Safety Workshop, Dallas, Texas, March 18-21, 2008

[4] Doan, D.M., “Designing a site electrical system with arc flash energy under 20 cal/cm2”, IEEE IAS Electrical Safety Workshop, Dallas, Texas, March 18-21, 2008.

[5] H. L. Floyd, D.R. Doan, C. T. Wu, S. L. Lovasic, “Arc Flash Hazards and Electrical Safety Program Implementation”, 2005 Industry Applications Society Annual Meeting, October 2-6, 2005

[6] Bretchken, D., “Preventive arc fault protection”, Transmission and Distribution Conference and Exposition, Atlanta, GA, USA, 28th Oct-2nd Nov 2001, p. 311-316, IEEE 2001

[7] Lee, W.-J., “Early stage arcing fault detection for medium/low voltage switchgear”, 2007 IAS Electrical Safety Workshop, 27th Feb-2nd March.2007, Calgary, Canada

[8] Sen, P.K., Nelson, J.P., “System grounding, ground fault protection and electrical safety: a new book on electrical safety”, IEEE IAS/PCIC 14th Annual Electrical Safety Workshop, Calgary, Canada, February 27-March 2, 2007

[9] Kay, J.A., Sullivan, P.B., Wactor, M., “Installation and application considerations of arc resistant medium voltage control equipment”. Paper No PCIC-2007-5, IEEE PCIC Technical Conference, 17-19 September, 2007

[10] Swencki, S.J, Smith, J.E., Roybal, D.D., Burns, D.B., Wetzel, G.E., Mohla, D.C., “Electrical safety, arc flash hazards, and “the standards”, a comprehensive overview”, IEEE PCIC, September 12-14, 2005

[11] Jones, R.A., Liggett, D.P., Capelli-Schellpfeffer, M., Macalady, T., Saunders, L.F., Downey, R.E., McClung, B., Smith, A., Jamil, S., Saporita, V., “Staged tests increase awareness of arc-flash hazards in electrical equipment”, IEEE Transactions on Industry Application, Vol. 36, No 2, March/April 2000

[12] Malmedal, K., Sen, P.K., “Arcing fault current and the criteria for setting ground fault relays in solidly-grounded low voltage systems”, IEEE Industrial and Commercial Power Systems Technical Conference, 2000

[13] Buff, J., Zimmerman, K., “Application of existing technologies to reduce arc-flash hazards”, 60th Annual Conference for Protective Relay Engineers, 27-29 March, 2007, College Station, Texas

[14] Arvola, J., Vähämäki, O., “Integrated arc protection concept”, Western Protective Relay Conference, Spokane, WA, October 19-21, 2004

[15] IEEE Standard 1584™-2002, “IEEE Guide for Performing Arc-Flash Hazard Calculations”, IEEE, 2002

[16] J.R. Dunki-Jacobs, “The escalating arcing ground-fault phenomenon”, IEEE Transactions on industry applications, VOL. IA-22, NO.6, November/December 1986”

[17] IEC 62271-200, “High-voltage switchgear and controlgear – Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV”, International Standard

IV. VITA

John A. Kay (M’94, SM’98). In 1977, he received his degree

in Electrical/Electronic Engineering Technology from Conestoga College, Kitchener, Ontario. He has authored a wide variety of award winning technical papers and other technical articles and manuals related to medium voltage electrical control and protection systems, arc resistant equipment and infrared technologies. Several of his papers have been published in the IEEE IAS Transactions and the IAS magazine. He is a senior member of the IEEE, the Industry Application Society and actively involved with the IEEE Pulp and Paper Industry Committee, serving on its main executive board, on the conference committee and on several sub-committees. He is an active member in several other technical groups including the local planning committee for the 2011 IEEE-PCIC. He was won several IEEE paper awards and was recently awarded a Meritorious Service Award from the IEEE Pulp and Paper Industry Committee. Mr. Kay is a Certified Engineering Technologist, in the province of Ontario.

Juha Arvola, received his Bachelor's degree in Electrical and Electronic Engineering (1998) from Vaasa University of Technology. His employment experience includes posts as a protection engineer as well as various protective relay application engineering and sales positions at ABB. Currently he holds the post of Sales Director with Vamp Ltd. He is a member of IEEE and has authored several technical papers on power system protection.

Lauri Kumpulainen, received his Master's degree (1987) and Licentiate degree (2000) in Electrical Power Engineering from Tampere University of Technology. His employment experience includes posts as development engineer with Hämeen Sähkö - electric utility, as principal lecturer with Central Ostrobothnia Polytechnic, and as research scientist with VTT Technical Research Centre of Finland. Currently he holds the post of Research Director with Vamp Ltd. One of his career highlights was the organizing and acting as a coordinator of the Finnish national “Technology Vision of the Future Power System” project. He is a member of IEEE, CIGRE, IEC Technical Committee 95, and a member of CIRED Session 3 Advisory Group and has authored various technical papers.