f.martzloff@ieee.org

Reprinted, with permission, from IEEE Transactions on Industry Applications IA-29, July/August 1993 

First presented as ICPSD 91-28 at the IEEE-IAS Annual Meeting, Dearborn, 1991

Significance: 

Part 8 – Coordination of cascaded SPDs 

For a “cascade” of two MOV-based SPDs, the combined numerical modeling and the laboratory 

measurements cross-validate to provide information on the relationship of impinging waveform and 

amplitude, distance between the two SPDs, and relative values of the SPD limiting voltage. 

Results show that separate selection of the service entrance SPD and point-of-use SPD can produce an 

ineffective coordination, with the point-of-use SPD “protecting” the service entrance SPD and in so doing

take on the dissipation of a disproportionate part of the impinging surge energy. 

This situation make the case for giving careful attention to the selection of device parameters, such as 

providing the two devices from an authoritative source from which a well-engineered approach should b

expected. 

Filename: Coordination 1993 
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 29, NO. 4, JULYIAUGUST 1993 

Coordinating Cascaded Surge Protection 

u 

Jih-Sheng Lai and Fran~ois 

Devices: Hinh-Low versus Low-High 

D. Martzloff, Fellow, IEEE 

Abstract- Cascading surge protection devices located at the 

service entrance of a building and near the sensitive equipment 

is intended to ensure that each device shares the surge stress in 

an optimum manner to achieve reliable protection of equipment 

against surges impinging from the utility supply. However, depending on the relative clamping voltages of the two devices, their 

separation distance, and the waveform of the impinging surges, 

the coordination may or may not be effective. The paper provides computations with experimental verification of the energy 

deposited in the devices for a matrix of combinations of these 

three parameters. Results show coordination to be effective for 

some combinations and ineffective for some others, which is a 

finding that should reconcile contradictory conclusions reported 

by different authors making different assumptions. From these 

results, improved coordination can be developed by application 

standards writers and system designers. 

R ECENT PROGRESS in the availability of surgeprotective devices, combined with increased awareness 

of the need to protect sensitive equipment against surge 

voltages, has prompted the application of a multistep cascade 

protection scheme. In the multistep cascade scheme, a highenergy surge protective device would be installed at the 

service entrance of a building for the purpose of diverting the 

major part of the surge energy. Then, surge-protective devices 

with lower energy-handling capability and lower clamping 

voltage than that of the service entrance would be installed 

downstream and complete the job of protecting sensitive 

equipment at the point of entry of the line cord. To make the 

distinction between these two devices, we will call the service 

entrance "arrester" and the downstream device "suppressor," 

somewhat in keeping with U.S. usage of the transient voltage 

surge suppressor (TVSS) for devices used on the load side 

of the mains disconnect. Such a scheme is described as 

"coordinated" if, indeed, the device with high-energy handling 

capability receives the largest part of the total energy involved 

in the surge event. 

Paper ICPSD 91 -28, approved by the Power Systems Protection Committee 

of the IEEE Industry Applications Society for presentation at the 1991 Industry 

Applications Society Annual Meeting, Dearborn, MI, September 28-October 

4. This work was supported by the Electric Power Research Institute, Power 

Electronics and Control Program, Customer Systems Division. Contributions 

from U.S. Government personnel are not protected by U. S. Copyright. 

Manuscript released for publication September 11, 1992. 

J. S. Lai was with the Power Electronics Applications Center, Knoxville, 

TN 37932. He is now with the Engineering Technology Division, Oak Ridge 

National Laboratory, Oak Ridge, TN 37831-7280. 

F. D. Martzloff is with the National Institute of Standards and Technology, 

Gaithersburg, MD 20899. 

IEEE Log Number 9210072. 

This scenario was based on the technology of secondary 

surge arresters prevailing in the 1970's and early 1980's 

as well as on the consensus concerning the waveform and 

current levels of representative lightning surges impinging 

on a building service entrance. This consensus has gradually evolved toward recognition that the surge environment 

may include waveforms of longer duration than the classical 

8/20 ps current surge. ANSVIEEE C62.41-1991 [I] provides 

a description of the surge environment. With the emergence 

of new types of arresters for service entrance duty and the 

recognition of waveforms with greater duration than the classic 

8/20 ps impulse, a new situation arises that may invalidate the 

expectations of the cascade coordination scenario. 

Service entrance arresters were generally based on the 

combination of a gap with a nonlinear varistor element, which 

was the classic surge arrester design before the advent of 

metal-oxide varistors that made gapless arresters possible. 

With a gap-plus-varistor element, the service entrance arrester 

could easily be designed for a 175-V maximum continuous 

operating voltage (MCOV) in a 120-V (rms) system. The 

downstream suppressors were selected with a low level, driven 

by the perception that sensitive equipment requires a low 

protective level [2]. The scheme can work if there is a series 

impedance (mostly inductance) between the arrester and the 

suppressor because the inductive drop in the series impedance, 

added to the clamping voltage of the suppressor, becomes high 

enough to spark over the arrester gap. Thereafter, the lower 

discharge voltage of the arrester (made possible by the gap) 

ensures that the major part of the surge energy is diverted by 

the arrester, relieving the suppressor from heavy duty [3]. 

Now, if the arrester is of gapless type, its MCOV will 

determine its clamping level. Some utilities wish to ensure 

survival of the arrester under the condition of a lost neutral, 

that is, twice the normal voltage for a single-phase, threewire service connection. The "high-low" combination has been 

proposed, where the arrester clamping voltage is higher than 

that of the suppressor [4]. During the ascending portion of 

a relatively steep surge such as the 8120 ps, the inductive 

drop may still be sufficient to develop enough voltage across 

the terminals of the arrester and force it to absorb much 

of the impinging energy. However, during the tail of the 

surge, the situation is reversed; the inductive drop is now 

negative, and thus, the suppressor with lower voltage (not 

the arrester) will divert the current. For the new waveforms 

proposed in C62.41-1991 [I], this situation occurs for the 

1011000 ps where the tail contains most of the energy, 

and the relief provided by the arrester may not last past 

0093-9994/93$03.00 0 1993 IEEE 
LA1 AND MARTZLOFF: COORDINATING CASCADED SURGE PROTECTION DEVICES 68 1 

TABLE I 

CURVE FITTING RESULTS FOR CIRCUIT MODELING OFTHREE MOV'S 

MOV number k tr X ( Ib(v) 

the front part of the surge. For the low-frequency (5 kHz 

or less) capacitor-switching ring waves, the inductive drop 

will be much smaller than that occurring with the 8-,us 

rise time so that the additional voltage may be negligible, 

leaving the suppressor in charge from the beginning of the 

event. An alternate means has been proposed (Low-High) 

where the arrester clamping voltage is lower than that of the 

suppressor [5], [6]. Thus, a disagreement has emerged among 

the recommendations for coordinated cascade schemes: the 

1970-1980 perception and [4], suggesting a "High-Low" and 

the new "Low-High" suggestion of [5] and [6]. 

This paper reports the results of modeling the situation 

created by the emergence of gapless arresters and longer 

waveforms with the necessary experimental validation. These 

results cover a range of parameters to define the limits of a 

valid cascade coordination and serve as input to the surge protective device application guides now under development by 

providing a reconciliation of the apparent disagreement, which 

is actually rooted in different premises on the coordination 

parameters. 

11. MOV CIRCUIT MODELING 

The current-voltage (I-V) characteristic of a metal oxide 

varistor (MOV) has long been represented by an exponential 

equation, i.e., I = kV" [7]. This equation is only applicable in 

a certain voltage (current) range in which the I-V characteristic 

presents a linear relationship in a log-log plot. When the 

voltage exceeds this "linear region," the current increment rate 

starts dropping. A modified I-V characteristic is proposed here 

as expressed in (1). 

The parameters in (1) can be obtained from a minimum-errornorm curve fitting technique [8] using a manufacturer's data 

book [7] or experimental results. The parameters k and a can 

be obtained from fitting the data in the linear log-log region. 

The exponential term is added to cover the voltages that are 

higher than a threshold voltage V, and can be obtained from 

fitting the I-V characteristics in the higher current (voltage) 

region. Using (I), the MOV circuit model can be simply 

represented by a voltage-dependent current source. 

Model parameters in (1) can be obtained from the manufacturer's data book and verified by experiments. The parameter is 

typically a function of the MOV voltage rating. The threshold 

voltage Vo and coefficients X and C are functions of the voltage 

rating and the size. Table I lists curve fitting results for the 

001 01 1 to 100 1000 10000 

Peak Current (A) 

Fig. 1. MOV characteristics obtained from modeling results. 

TABLE I1 

PARAMETERS FOR NOMINAL I-V CHARACTERISTICS OF THREE MOV'S 

MOV number I; a X C 1 b(v) 

V130LA20A 9.4 x 10-M 27 0,046 0.8 x 10p6 2285 

V150LA20A 4.8 x 31.5 0.053 1.6 x 340 

V250LA40A 1.7 x 36 0.044 1.6 x lo-" 520 

equivalent circuit parameters of three MOV's for units of 

voltage and current in volts and amperes. 

The MOV number1 actually reflects the device voltage 

rating and the size. For V130LA20A, the continuous operating 

voltage rating is 130 V(rms). The other two devices are 150 

and 250 V(rms), respectively. All three devices have a 20-mm 

diameter. Fig. 1 shows fitted curves for the three devices. 

In Fig. 1, the marked dots were the data directly obtained 

from the manufacturer's data book, whereas the three solid 

lines were calculated from (1) using the parameters listed in 

Table I. 

It should be noted that each individual MOV may have 

slightly different I-V characteristics even with the same model 

number. In Fig. 1, the data show the maximum clamping 

voltage levels, which are 10% higher than the nominal voltage 

level. A typical off-the-shelf device has a tolerance within 

&lo% of the nominal voltage level, which means a lowestlevel device could have an I-V characteristic that is 20% lower 

than the data book characteristics. In fact, the two closely 

rated cascading devices (130 and 150 V) could, in some 

extreme cases, become inverted in the sequence ("Low-High" 

becoming in reality "High-Low") as 130 x 1.1 = 143 and 

150 x 0.9 = 135. Furthermore, the results show that for the 

250-150 combination, the difference is so large that a low 

250 (225 V) combined with a high 150 (165 V) would not 

make an appreciable difference in energy sharing. Thus, the 

simulation computations were performed for all three devices 

at their nominal values. From the maximum voltage tolerance 

parameters listed in Table I, the parameters for the nominal 

(zero tolerance) I-V characteristics were derived, as listed in 

Table 11. 

'Certain commercial products are identified in this paper in order to 

adequately specify the experimental procedure. Such identification does not 

imply recommendation or endorsement by the Power Electronics Applications 

Center or the National Institute of Standards and Technology, nor does it imply 

that the products are necessarily the best for the purpose. 

LA1 AND MARTZLOFF: COORDINATING CASCADED SURGE PROTECTION DEVICES 

Fig. 5. Simulated Combo Wave voltage responses for the 250-130 V cascaded devices that are 10-m apart. 

Fig. 6. Simulated Combo Wave power responses for the 250-130V cascaded 

devices that are 10-m apart. 

250-130, 10-m cascaded case but slightly higher peak surge 

current (3.3 kA instead of 3 kA in simulation), the experimental result shows 33.8 and 11.1 J energy depositions in 

the arrester and the suppressor, respectively. Prorating the 

simulation results from Fig. 6 to 3.3 kA would yield 32.7 

and 9.5 J, respectively, which is a reasonable agreement. 

Table IV lists Combo Wave simulation results of the energy 

deposition in the arrester (A) and suppressor (S) for all the 

combinations of different High-Low and Low-High cascade 

conditions. For the High-Low condition, the energy deposition 

in the suppressor increases when the distance decreases. This 

result explains how the High-Low configuration can achieve a 

good coordination under the Combo Wave, provided that there 

is sufficient distance between the two devices, as stated in [3]. 

Consider the High-Low configuration with a 250-V device 

as the arrester. When the distance between two devices is reduced, the energy deposition tends to increase in the suppressor 

and decrease in the arrester. This decrease occurs because 

the line inductance does not provide enough voltage drop 

(L dildt), and the low clamping voltage of the suppressor 

reduces the voltage across the arrester and thus reduces the 

energy deposition level. The total energy deposition in the 

two devices also varies with the distance for the HighLow configuration. In Table IV, the total energy deposition 

for the 250-250 combination is near constant at 103 J for 

different distances. However, for the 250-150 and 250-130 

combinations, the total energy deposition decreases when the 

distance is reduced because the suppressor tends to lower the 

voltage across the arrester. 

For Low-High configurations such as the 150-250 and 

130-250 cases, the high-voltage suppressor receives almost 

zero energy. The use of the suppressor is near redundant 

TABLE IV 

ENERGY DEPOSITION IN THE CASCADED DEVICES 

WITH A 3-kA COMBO WAVE AS THE SURGE SOURCE 

Clamping Distance separating devices and energy deposited in each 

voltage of device (J) 

device (V) 5 m 10 m 20 m 40 m 

ASASASASAS 

250 75.9 27.3 83.5 19.9 89.5 14.4 91.7 9.69 

in this case, except for its application to mitigate internally 

generated surges. With closely rated devices (130-150), the 

150-V voltage suppressor also receives much less energy than 

the 130-V arrester. 

B. Simulation Results with the 0.5 ps-100 kHz Ring Wave 

The energy deposition in the surge protection devices under 

the Ring Wave surge is considerably less than that of the 

Combo Wave because of lower current. However, the highfrequency Ring Wave shows similar characteristics to the 

Combo Wave under the High-Low cascade condition; a voltage 

drop between the two devices can be established by the line 

inductance, provided that there is sufficient distance between 

the two devices. Figs. 8 and 9 show simulation results of 

current and voltage for the cascaded arrester and suppressor 

under the High-Low condition. Il and Vl represent the 250- 

V arrester current and voltage, whereas 4 and V2 represent 

the 130-V suppressor current and voltage, respectively, for a 

400-A peak surge current. 

Fig. 10 shows the instantaneous power dissipated in the 

two cascaded devices. PI and P2 represent the 250-V arrester 

power and 130-V suppressor power, respectively. 

Table V lists the simulated energy deposition in the cascaded 

devices for different High-Low and Low-High combinations. 

The energy is the integration of the instantaneous power over 

the total 20-ps simulation period. Unlike the Combo Wave, 

the Ring Wave tail still contains a small amount of power, 

and the total amount of the energy deposition is affected by the 

integration interval. From Fig. 10, it is apparent that the power 

contribution to the total (past 20 ps) is becoming negligible. 

Similar to the Combo Wave, the High-Low configuration 

shows good coordination as the high-voltage arrester absorbs 

higher energy under the high-frequency Ring Wave surge, 

and the Low-High configuration shows almost zero energy 

deposition in the high-voltage suppressors. 

C. Simulation Results with the 10/1000 ps Long Wave 

Compared with the Combo Wave, the Long Wave has a 

slower and longer drooping tail that contains most of the surge 

energy. During the long tail period, the inductive voltage drop 

between the arrester and the suppressor is low due to low 

Ldildt, and the voltage across the arrester is reduced by the 
683 IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 29, NO. 4, JULYIAUGUST 1993 

1,+12 1000 Ndiv 

I, 1000 Ndl, 

I,+12. 1000 Ndiv 

I,: 1000 Ndlv 

Fig. 7. Experimental results for the 250-130 V cascade with devices that are 10-m apart, with the Combination Wave: (a) Arrester; (b) suppresor 

TABLE V 

ENERGY DEPOSITION IN THE CASCADED DLVICES WITH 

A 400-A PEAK RING WAVE AS THE SURGE SOURCE 

Clamping Distancc separating devices and energy deposited in each 

voltagc of device (J) 

device (V) 5 m 10 m 20 m 40 m 

ASASASASAS 

250 1.287 0.398 1.405 0.291 1.512 0.158 1.593 0.114 

suppressor even with long distance between the two devices. 

This makes the High-Low configuration not coordinated as the 

high-voltage arrester will not absorb any impinging energy, but 

the suppressor does. Figs. 11, 12, and 13 show the simulated 

Long Wave current, voltage, and power, respectively, for 

the arrester and the suppressor under a High-Low (250-130) 

configuration for a 200-A peak surge current. 

The high-voltage arrester clamps the voltage during the 

impulse rising period and draws a small amount of the current 

pulse 11, which is almost invisible in the computer-generated 

plot of Fig. 11. The power absorbed by the arrester PI is also 

a small pulse that appears at the rising period as shown in 

Fig. 13. The low-voltage suppressor absorbs all the impinging 

energy in this High-Low configuration, defeating the intended 

coordination. 

Table VI lists the simulated energy deposition in the cascaded devices for different High-Low and Low-High combinations as well as for different distances. 

It can be seen from Table VI that the low-voltage device 

always absorbs higher energy than the high-voltage device 

because the voltage across the high-voltage device is clamped 

to the same level as that of the low-voltage device, and the 

energy is diverted to the low-energy device. Unlike the Combo 

Wave and the high-frequency Ring Wave, the coordination for 

Fig. 8. Simulated Ring Wave current responses for the 250-130 V cascaded 

devices that are 10-m apart. 

Fig. 9. Simulated Ring Wave voltage responses for the 250-130 V cascaded 

devices that are 10-m apart. 

the slow Long Wave can only be achieved by Low-High or 

equally rated devices (250-250, 150- 150, and 130- 130). Note 

that with two devices of equal nominal value, it is possible 

that the relative tolerance might, in fact, produce a HighLow situation, which would not achieve good coordination; 

for instance, a 150-130 combination resulting from tolerance 

shifts imposes a 70-J duty to the suppressor in the case of 

5-m separation. 

IV. EXPERIMENTAL RESULTS 

In order to verify the validity of the simulation, a series 

of experiments has been conducted using the three waves for 

different High-Low and Low-High combinations, especially 
LA1 AND MARTZLOFF. COORDINATING CASCADED SURGE PROTECTION DEVICES 685 

Fig. 10. Simulated Ring Wave instantaneous power for the 250-130 V 

cascaded devices 10-m that are apart. 

Fig. 11. Simulated Long Wave current responses for the 250-130 V cascaded 

devices that are 10-m apart. 

Fig. 12. Simulated Long Wave voltage responses for the 256130 V cascaded devices that are 10-m apart. 

for the Long Wave, which has not been used for cascaded 

coordination studies in the literature. Table VII lists experimental results (from Figs. 7, 14, and 15) using the three 

waveforms for 250-130 V cascaded devices that are 10-m 

apart. Note that peak currents do not occur simultaneously. 

A * sign shows that the low-voltage suppressor absorbs 

almost all the energy under the 1011000 ps Long Wave. The 

experimental results, in general, agree with the simulation 

results, especially for the Combo Wave, which has well 

matched surge sources and a limited surge period (the tail does 

not extend over the integration period). For the Ring Wave 

and the long wave, the total integration period and the surge 

source are not matched between simulation and experiment, 

and thus, the numbers in Table VII have higher deviation 

from the simulation results. However, the proportion between 

the arrester and the suppressor energies agrees well between 

simulation and experiment, which explains that the simulation 

can be effectively used for the coordination analysis. 

Fig. 13. Simulated Long Wave power responses for the 256130 V cascaded 

devices that are 10-m apart. 

TABLE VI 

ENERGY DEPOSIT~ON IN THE CASCADED DEVICES 

wrr~ A 220-A PEAK LONG WAVE SURGE SOURCE 

Clamping Distance separating devices and energy deposited in each 

voltage of device (J) 

device (V) 5 m 10 m 20 m 40 m 

ASASASASAS 

250 73.63 72.76 74.10 72.31 75.06 71.38 76.28 70.13 

TABLE VII 

EXPERIMENTAL RESULTS USING DIFFERENT WAVEFORMS FOR 

250-130 V CASCADEDEVICES THAT ARE 10-M APART 

Applied Arrester Suppressor 

Wave VL (V) Ink (A) W (J) VDk (V) Inn (A) fi'(J) 

790 2600 33.8 400 1000 11.1 3 kA pk 43pigpk 720 340 0.6 350 100 0.2 

Long 

220 A pk 450 6 0.05 320 220 64.4* 

The experimental verification of the Combo Wave for the 

simulation can be seen from Fig. 7. For the Ring Wave and the 

Long Wave, experimental current, voltage, and power waves 

are shown in Figs. 14, 15, and 16, respectively. The Ring Wave 

coupled from the surge generator is distorted and is attenuated 

much faster than the standard Ring Wave. The measurement 

of the coupled Long Wave shows a saturation on the small 

CT (5000 A peak and 65 A rms rated). However, the current 

flowing through the surge protection devices were measured 

by a large CT (20 000 A peak and 325 A rated) and were 

not saturated. 

The experimental Long Wave response for a Low-High 

configuration is shown in Fig. 16, where Il and I2 are 

the currents flowing in the 130-V arrester and the 150-V 

suppressor, respectively. This figure shows an example of good 

coordination by Low-High, where most of the surge energy is 

absorbed by the low-voltage arrester. The arrester voltage VI 

is almost the same as the suppressor voltage V2 with a slight 

difference at the beginning of the surge. 
lEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 29. NO. 1. JULYIAUGUST 1993 

lh 

I,+], 100 Ndlv l,+lz 100 Ndlv 

1, 100 A/d~v I2 100 Ndiv 

Fig. 14. Experimental results for the 250b130 V cascade, with devices that are 10-m apart, with the Ring Wave: (a) Arrester; (b) suppresor. 

I,+/,: 50 Mdiv 

I?: XO Ndiv 

(a) (b) 

Fig. 15. Experimental results for the 250-130 V cascade, with devices that are 10-rn apart, with the Long Wave: (a) Arrcsler; (b) auppresor. 

V. DISCUSSION 

The concept of coordination of surge-protective devices is 

based on the selection of a first device with high energyhandling capability that is to be located at the service entrance 

and is expected to divert most of the surge current at that point. 

The second device, which is installed within the premises, can 

then have a lower energy-handling capability. 

The benefit from this coordinated approach is to allow a 

single device at the service entrance to perform the high-energy 

duty, whereas several smaller devices within the premises 

can perform local suppression. This arrangement avoids the 

flow of large surge currents in the branch circuits of the 

installation, which is a situation known to produce undesirable 

side effects [l 11. 

On the other hand, the situation where millions of small 

suppressors have been installed within equipment, or as plugin devices, exists with only sporadic and anecdotal reports of 

problems. Thus, it is evidently possible to obtain protection 

with suppressors alone, whereas a coordinated scheme would 

provide additional bcnefits and eliminate side effects. 

Some utilities wish to provide a service-entrance arrester 

thta is capable of withstanding the 240-V overvoltage that 

can occur on the 120-V branches when the neutral is lost. 

V,. 200 V/dlv 

V; 200 V/div 

Fig. 16. Experimental results for the 130-150 V cascade, with devices that 

are 10-m apart, with thc Long Wave. 

This desire will force the coordination scheme into a HighLow situation because of the uncontrolled installation of low 

clamping voltage suppressors by the occupant of the premises. 

The results of the simulation and experimental measurements 
LA1 AND MARTZLOFF: COORDINATING CASCADED SURGE PROTECTION DEVICES 

show that the objective of coordination could still be achieved 

with a 250-130 combination, as long as some distance is 

provided between the two devices and as long as Long Waves 

are not occurring with high peak values. This proviso provides 

an incentive for obtaining better statistics on the occurrence 

of Long Waves. ANSUIEEE C62.4 1 - 199 1 [4] recommends 

considering these Long Waves as an additional and not a 

standard waveform. Thus, the determination of a successful 

coordination depends, for the moment, on the perception of 

what the prevailing high-energy waveforms can be for specific 

environments. 

VI. CONCLUSIONS 

1. Coordination of cascaded devices can be achieved under 

various combinations of parameters, but some combinations will result in having a suppressor with low 

energy-handling capability called on to divert the largest 

part of the surge energy. This uncoordinated situation 

can create adverse side effects when high current surges 

occur. 

2. Significant parameters in achieving successful coordination involve three factors over which the occupant 

of the premises has no control: the relative clamping 

voltages of the two devices, their separation distance, 

and the prevailing waveforms for impinging surges. This 

uncontrolled situation presents a challenge and obligation for standards-writing groups to address the problem 

and develop consensus on a tradeoff of advantages and 

disadvantages of High-Low versus Low-High. 

3. Coordinated schemes can be proposed by utilities to 

their customers, including a service entrance arrester 

and one or more plug-in devices to be installed for the 

dedicated protection of sensitive appliances. However, 

even such an engineered, coordinated arrangement could 

be defeated by the addition of a suppressor with a 

very low clamping voltage, which is not an insignificant 

likelihood in view of the present competition for lower 

clamping voltages. 

VII. UPDATE ON COORDINATION EFFORTS 

Since the presentation of the paper in the Fall of 1991, considerable discussion of the coordination issue has taken place 

at the international level involving five technical committees 

of the IEC. As of late 1992, an effort is underway within 

the IEC to develop an application document that will address 

the issues discussed in this paper and present recommendations tailored to the specific neutral-grounding practice of 

the various member countries. Contact the authors for further 

updates on progress concerning the technical aspects of device 

coordination issues as well as updates on the intercommittee 

coordination and liaison. 

The authors wish to thank W. P. Malcolm of EPRI for 

his continued support. Thanks are also due to A. M. Maher 

and R. A. Veira of PEPCO and T. S. Key of PEAC for their 

encouragement in this project. 

[I] ANSILEEE C62.41-1991, IEEE Recommended Practice on Surge Voltages in Low-Voltage ac Power Circuits. 

[2] F. D. Martzloff and T. F. Leedy, "Selecting varistor clamping voltage: 

Lower is not better!" in Proc. 1989 EMC Symp. (Ziirich). 

[3] F. D. Martzloff, "Coordination of surge protectors in low-voltage ac 

power circuits," IEEE Trans. Power App. Syst., vol. 99, pp. 129-133, 

Jan./Feb. 1980. 

[4] M. F. Stringfellow and B. T. Stonely, "Coordination of surge suppressors 

in low-voltage ac power circuits," in Proc. Open Forum Surge Protection 

Application, NISTIR 4657, June 1991. 

[5] R. B. Standler, "Coordination of surge arresters and suppressors for use 

on low-voltage mains," in Proc. 1991 EMC Symp. (Ziirich). 

[6] IEC 641WG3 138A, "Explanation of interfaces for overvoltage categories," Supplement to Appendix B of Rep. 664, Nov. 1990. 

[7] Transient Voltage Suppression Devices, Harris Cop., 1991. 

[8] D. G. Luenberger, Linear and Nonlinear Programming. Reading, MA: 

Addison-Wesley, 1984. 

[9] F. D. Martzloff, "On the propagation of old and new surges," in Proc. 

Open Forum Surge Protection Application, NISTIR 4657, June 1991. 

[lo] J. S. Lai, "Performance criteria for cascading surge-protective devices," 

in Proc. Open Forum Surge Protection Application, NISTIR 4657, June 

1991. 

[I 11 F. D. Martzloff, "Coupling, propagation, and side effects of surges in an 

industrial building wiring system," IEEE Trans. Industry Applications, 

vol. 26, no. 2, pp. 193-203, Mar./Apr. 1990. 

Jih-Sheng (Jason) Lai is a native of Taiwan. He 

received the M.S. and Ph.D. degrees in electrical engineering from the University of Tennessee, 

Knoxville, in 1985 and 1989, respectively. 

From 1980 to 1983, he was the Electrical Engineering Department Chairman of Ming-Chi Institute 

of Technology, Taipei, Taiwan, where he initiated 

a power electronic program and received a grant 

from the school and the National Science Council 

to study abroad. In 1989, he joined the EPRI Power 

Electronics Applications Center. He is currently the 

Power Electronics Lead Scientist at thk Engineering Technology ~i~ision 

of the Oak Ridge National Laboratory. His main research interests are 

power electronics modeling and simulation, circuit design, and microcomputer 

applications. In the surge protection area, he developed varistor models 

and simulated cascaded surge protection circuits to understand more about 

fundamental concepts. 

Dr. Lai has two patents in high-frequency power conversions for adjustablespeed drives and more than 25 articles published in the fields of control 

systems, power systems, and power electronics. 

Franqois D. Martzloff (F'83) is a native of France. 

After undergraduate studies there, he received the 

M.S.E.E. degree from Georgia Institute of Technology, Atlanta, in 1952 and the M.S.I.A. degree from 

Union College, Schenectady, NY, in 1972. 

After 32 years in the private sector (Southern 

States Equipment from 1953-1956 and General 

Electric form 1956-1985). he joined the National 

Bureau of Standards, which is now the National Institute of Standards and Technology, Gaithersburg, 

MD. His early professional experience included the 

design of high-voltage fuses and bushings. He changed to semiconductor 

technology, but his high-voltage experience led him to the study of transients, 

which he has steadily pursued for the last 30 years. He has contributed a 

number of papers and led the development of several standards on surge 

characterization and surge testing. 

Mr. Martzloff has been granted 13 patents, mostly on surge protection. In 

the IEEE, he serves as Chair of the Working Group on Surge Characterization. 

In the IEC, he is serving as Convenor of two working groups and chairs Subcommittee 77B (High-Frequency Phenomena) of TC77 on Electromagnetic 

Compatibility.