TVSS Installation Tech Study

8/8/2019 TVSS Installation Tech Study

1/15

REFERENCE 2004-1005-002ED

Date October 05, 2004

GROWTH POLYGON JAB ELICOMS & ASSOCIATES

TECHNICAL STUDY & EVALUATION(ELECTRICAL DIVISION)

Prepared Checked Noted ReceivedProject

NameInstallation of Transient VoltageSurge Suppressor (TVSS) In Local

Exchanges (LEC) and RelayStations (RS)

C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB

ELICOMS & ASSOCIATES

COPY: GLOBE, SUMITOMO,

SUMICONPAGE 1 OF 29

This document refers to the result of the technical study conducted on the above-indicated project

for the preparation of feasibility study by the proponent.

I. PROJECT BRIEFClient Name : All LEC(Cel lSites) and RS(Relay Stati ons) Operations

Project Locations : See Distribution

Service Requirement(s) : Engineering Study And Technical Evaluation

Description:

The project involves the installation of transient voltage surge suppressors to counter

the effects or damages to electro-mechanical equipment caused by over-voltages,spikes, transients and RFI-induced disturbance in the electric power lines of the sites

mentioned.

Most RS stations power supply are very prone to lightning strikes and line faults. Amajor study done by General Electric verified several facts about electrical surges:

Up to 80% of electrical surges that can damage equipment are actuallygenerated within the electrical system of the facility where they occur.

Only about 20% of damaging surges come from external sources, i.e. lighting,power and adjacent company switching operations.

In reality, while dramatic in appearance, lightning only causes a statistically minor

percentage of damage done by surges. In order to minimize and/or totally eliminate

these power disturbances from entering the power lines, transient voltage surgesuppressors must be installed within the exchanges and relays power systems,configured in such a way, so that transients and surges coming from the power lines will

be cutoff and diverted to the ground.

II . PROJECT CONSIDERATIONSSupply of Labor and Equipment

o Contractor will supply supply of labor and materials.o TVSS units must have at l east 10 years replacement warranty.

Budget Allocation and Site Distribution

o Engineering and Facilities Management will handle the budget for the installationof TVSS units.








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICONPAGE 2 OF 29

Surge Ratings

o The Total Short Circuit Current of most LECs is only 9.233 KA. The currentcommercial standards are 40 KA, 50 KA, 65 KA, 100 KA, 150 KA. The nearest

value to our requirement is the 40 KA surge rating. Hence all TVSS unitswill be rated at 40 KA Short Circuit Current Rating.

o TVSS devices rated above 200 KA are a poor investment, especially wherebudgets are limited. The new IEEE C62.41.2 provides a welcome reality check

with its recommendation of a 100KA 8/20 microseconds surge rating forexposed service entrance locations(increased from 10KA 8/20microseconds).

AC service entrance surge amplitudes larger than 100 KA are extremely rare.The service lines and equipment insulation are not high enough to allow

sufficient voltage to develop to generate this current at the facility servicepanel. The only justifiable reason for larger surge ratings is to provide longer

TVSS life because each doubling of surge rating provides two to five times thelength of life.

o A number of sources provide information on the statistical distribution of thecurrent discharge of the direct lightning strike. The diagram below shows that

discharges above 100kA 8/20s are likely to occur less than 5% of the time.Combined with the fact that most discharges do not strike the power line

directly but are magnetically or capacitively coupled to i t, and that even undera direct strike to the line the energy will split in either direction and be

attenuated by the distribution class arresters, it is not hard to realize thatonly a small fraction of this initial energy actually enters the facility of

concern.

ANSI/IEEE standard C62.41 has classified the service entrance environmentas Cat B/Cat C. Under this classification the highest expected energy level is

10kA 8/20s. IEEE argues its case by pointing to many years of data collectedfor observed failure rates of equipment and impulse insulation of the supply

system. Put simply, electrical insulation at the service entrance will not allow


2/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICONPAGE 3 OF 29

enough voltage to develop to source currents in the magnitude of hundreds ofkAs. Recent work within the IEEE by respected scientists and academics may

see the Cat C reclassified to levels nearer a maximum single shot rating of100kA 8/20s. It is important to note this 100kA rating includes its ownsafety overhead, thus higher surge ratings are not required. In addition, the

10/350s waveshape may be introduced, up to 5kA.

A study that classifies the electrical environment of the primary serviceentrance to a facility can be found in a 10-year independent study completed

during the 1970s. The purpose of this long duration study was to betterunderstand the frequency and magnitude of surges, which a typical building

might experience in a location of average isokeraunic level, to better protectthe computer mainframe installations. This again confirms the observation

that large surges (>70kA) are rare, but multiple smaller surges are common.

Installation Locations

Service Entrance Locations

o Surge protection devices installed at high exposure service entrance locationsprovide the first line of defense. Here, transient amplitudes are suppressed tolevels that can be handled by succeeding surge protection devices. Surge

protection installed at the service entrance should be of Category A type.This means that it is rated to filter out the bulk (or large) surges, but will

still pass through a voltage level that could be harmful to electronicequipment.

Branch Panel Locationso Typically, sensitive and critical load equipment is fed from these highly

important branch panels. SPDs installed at branch panel locations aredesigned to address changing transient characteristics.

Telecom and Data Circuits Locationso Telecom and data circuits are extremely vulnerable to transients, especially at

building entry points. Even relatively low energy transients can take down

computer, LAN, telephone and other systems. SPD installed at these locationsprovide the best possible protection for these sensitive and mission-critical

systems.Individual Circuit P rotection

o Process control, sensing/monitoring and DC power supplies may all requireindividual equipment protection. In addition, plug-in units installed at point-

of-use locations provide added protection against externally-generatedtransients as well as addressing internally-generated transients.








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICONPAGE 4 OF 29

III. RECOMMENDATION/ PROPOSED SOLUTIONA. TVSS UNIT LOCATIONS

o Each LEC must be i nstalled with three (3) TVSS units at the following l ocations:o MDP Panel - EE Room, input side, parallel or shunt connectiono EDP Panel - Switch Room, input side, series connectiono CPPU Panel - EE Room, input side, series connection

o Each Relay Stations (RS) must be installed with one (1) TVSS units at thefollowing locations:

o MDP Panel - EE Room, input side, Series Connection

B. TVSS TYPE SELECTIONo There are many parameters to be considered, when designing an effective

suppression unit. We have opted to select a combination of SADs and MOVbecause SADs alone would be far too costly for a unit designed to take the same

amount of energy. The silicon avalanche diodes provide a very rapid responsewhile the metal oxide varistors give us the large current capacity. In addition the

presence of SADs will prevent the clamping voltage rising, as the MOVs takemore current. In principle, this sounds an ideal combination, although careful

consideration must be given to the response curves of the two devices. Becausethe SADs react so much quicker, there is a danger that they will be subjected to

over current before the MOVs start to conduct. Consequently, it would beinadvisable to use only a few SADs in conjunction with the MOVs, to reduce costsfurther.

Hence, we recommend the following technologies:

o Active Tracking Network By Innovative Technologyo Threshold Suppression Network By Innovative Technologyo Triggered Spark Gap Technology By ERICOo Transient Discriminating Technology By ERICO

If technology is taken from ERICO/CRITEC, Triggered Spark Gap Technology forseries connection must be used while Transient Discriminating Technology will beused for parallel or shunted connections. The fol lowing models will be used:

For Relay Stations:System : Li ne To Ground, singl e phase, 220 VoltsTVSS Models : TSG-SRF 163 or TSG-SRF 140


3/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICONPAGE 5 OF 29

For Local Exchanges:System : Three Phase, Open Delta, Delta Grounded corner, 220 Volts

TVSS Models : TDX100 240DTSG-SRF 363TSG-SRF 163 or TSG-SRF 140

If technology is taken from Innovative Technology, Active Tracking Network

for series connection must be used while Threshold Suppression Network willbe used for parallel or shunted connections.

For Relay Stations:

System : Line To Ground, singl e phase, 220 VoltsTVSS Model s : HS 250-30A-PH, ATN

For Local Exchanges:System : Three Phase, Open Delta, Delta Grounded corner, 220 Volts

TVSS Models : XT40-NN201-PH, TSNHS 250-30A-PH, ATN

C. CONFIGURATION (ALTERNATIVE 1)o This configuration offers the best protection. This is how protection is

conducted:o Let-through voltage from the MDP is around 600-800 volts for 40

microseconds.o Let-through voltage from the MDP (600-800 volts for 40

microseconds) is further clamped down in the EDP to 275-350 volts for200 microseconds.

o Let-through voltage from the MDP (600-800 volts for 40microseconds) is further clamped down in the CPPU/UPS to 275-350volts for 200 microseconds.

o Financially, this is also costly but the protection is very muchimproved.








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICONPAGE 6 OF 29

LOCAL EXCHANGES

o The configuration shown below should be strictly followed for Local Exchanges.

CPPU

100AT

UPS

CPP

60AT

LPPB

60AT

LPPA

60AT

EDP

300

AT

MPP

300

AT

3-125+50

2-14+5.52-14+8.0

2-14+8

2-14+5.5

2-14 + 5.5

GENSET,3 PHASE225 KW,3 PHASE,230 VOLTS,60 HZ,1800

RPM,STANDBY

3 SETSOF 2-200+100

COMMERCIALLINE,230 VOLTS,60 HZ

TYPICAL LEC SINGLE LINE POWER DIAGRAMWITH TVSS INSTALLATION DISTRIBUTION

Notes:1. All equipment grounding wires must be terminated on the groun ding terminal provided

bythe TVSSequipment.

MDP

BUSBAR

2-14+5.5

Max length ofL e a d W i r e sMust Not ToE x c e e d 6

Inches For T-Connection

Abbreviations:TVSS - Transient Voltage Surge SuppressorTSN -ThresholdSuppressionNetworkATN - Act ive Tracking NetworkPSC/P - Peak Surge Current Per PhaseTSC - Total Surge CapacityVAC - Volts, Alternating CurrentKA - Ki lo Am pe re sTSG - Triggerred Spark GapTD -TransientDiscriminating

TRANSIENT VOLTAGESURGE

SUPPRESSOR(TVSS),SHUNT PROTECTION,

TSN OR TD

TRANSIENT VOLTAGESURGE

SUPPRESSOR(TVSS),SERIESPROTECTION,

ATN OR TSG

2-14+5.5

3-125+50

3-125+50

TRANSIENTVOLTAGESURGE

SUPPRESSOR(TVSS),SERIESPROTECTION,

ATN OR TSG

MDP


4/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICONPAGE 7 OF 29

RELAY STATIONS

o The configuration shown below should be strictly followed for Relay Stations.Transient voltage from the incoming lines is automatically clamped down to 275-

350 volts for 200 microseconds.








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICONPAGE 8 OF 29

D. CONFIGURATION (ALTERNATIVE 2)o This configuration still offers the best protection. This is how protection is

conducted:

o Let-through voltage from the MDP is around 600-800 volts for 40microseconds.

o Let-through voltage from the MDP is treated in the EDP as normalover-voltage condition. The TVSS equipment thus clamped down thevoltage to 275-350 volts for 200 microseconds.

o Let-through voltage from the MDP (600-800 volts for 40microseconds) is further clamped down in the CPPU/UPS to 275-350

volts for 200 microseconds.o Financially, this is also costly but the protection is very much

improved.


5/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICONPAGE 9 OF 29

LOCAL EXCHANGES

o The configuration shown below should be strictly followed for Local Exchanges.

CPPU

100AT

UPS

CPP

60AT

LPPB

60AT

LPPA

60AT

EDP

300AT

MPP

300AT

3-125+50

2-14+5.52-14+8.0

2-14+8

2-14+5.5

2-14 + 5.5

GENSET, 3 PHASE225 KW, 3 PHASE, 230 VOLTS, 60 HZ, 1800

RPM,STANDBY

3 SETS OF2-200+100

COMMERCIALLINE, 230 VOLTS, 60 HZ

TYPICAL LEC SINGLE LINE POWER DIAGRAM

WITH TVSS INSTALLATION DISTRIBUTION

Notes:

1. All equipment grounding wires must be terminated on thegr ounding terminal providedbythe TVSSequipment.

MDP

BUSBAR

2-14+5.5

Max length of

L e a d W i r e sMust Not ToE x c e e d 6Inches For T-Connection

Abbreviations:TVSS - Transient VoltageSurge SuppressorTSN - ThresholdSuppressionNetworkATN - Active Tracking NetworkPSC/P - Peak SurgeCurrent Per PhaseTSC - Total SurgeCapacityV AC - V ol ts ,Alternating Current

K A - Ki lo Amper esTSG - Triggerred SparkGapTD -TransientDiscriminating


SUPPRESSOR(TVSS),SHUNTPROTECTION,

TSN OR TD


SUPPRESSOR(TVSS),SERIES PROTECTION,

ATN OR TSG

2-14+5.5

3-125+50

3-125+50


SUPPRESSOR(TVSS),SERIES PROTECTION,

TSN OR TD

MDP








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICONPAGE 10 OF 29

RELAY STATIONS

o The configuration shown below should be strictly followed for Relay Stations.Transient voltage from the incoming lines is automatically clamped down to 275-

350 volts for 200 microseconds.


6/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB




E. EXISTING POWER DIAGRAMLOCAL EXCHANGES

13.2 KV

13.2 KV

13.2 KV

CooperativeSubstation

TransmissionLines

LEC/CELL SITE

220 V

220 V

220 V

MTS MDP

Ground

Mesh

Cooperative

Ground

POWER SUPPLY CONFIGURATION








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB




RELAY STATIONS

13.2 KV

13.2 KV

CooperativeSubstation

TransmissionLines

RS/CELL SITE

220 V

220 V

MTS MDP

GroundMesh

Cooperative Ground

POWER SUPPLY CONFIGURATION


7/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB




F. SHORT CIRCUIT CURRENT CALCULATIONS:LOCAL EXHANGES LOAD FAULT CALCULATIONS

For 13.2 KV System Distribution:

Ib = (MVA) / (1.73 X K V)

I b = (0.150 MVA) / (1.73 X 0.220 KV)

= 0.3936 KA

X = (Ib / I s) X (Vs / Vp)= (0.3936 KA / 21 KA) X (0.22 KV / 13.2 KV)= 0.00031238

X/ R = 15

R = X / 15= 0.00031238 / 15

= 0.000020825








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB




For Transformer:

Z = X = 5 .5%

= 0.055

X/ R = 10R = X / 10

= 0.00031238 / 10

= 0.0.0055

For Connected Loads:

Since X/R is negligible, then Z = X

For Each Connected Load

Z =X = Vs / I b= 0.220 KV / 0.3936 KA

= 0.5589

Calculation for Short Circuit Duty OR Interrupting E/ X Amperes:

For 13.2 KV Distribution and Transformer:

XT = X13.2 KV + XTRANSFORMER= 0.00031238 + 0.055= 0.05531238

I3phase =Interrupting E/X Amperes.

I3phase = IB / XT= 0.3936 / 0.05531238= 7.12 KA

For the 3 Connected loads:

XT = XCONNECTED LOAD= 0.5589

I3phase =Interrupting E/X Amperes.I3phase = (IB / XT) X 3

= (0.3936 / 0.5589) X 3= 2.113 KA

Total Interrupting E/ X Amperes = 7.12 KA + 2.11 KA= 9.233 KA


8/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB




B. RELAY STATIONS LOAD FAULT CALCULATIONS

For 13.2 KV System Distribution:

Ib = (MVA) / (1.73 X K V)I b = (0.150 MVA) / (1.73 X 0.220 KV)

= 0.3936 KA

X = (Ib / I s) X (Vs / Vp)= (0.3936 KA / 21 KA) X (0.22 KV / 13.2 KV)= 0.00031238

X/ R = 15

R = X / 15= 0.00031238 / 15

= 0.000020825








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB




For Transformer:

Z = X = 5 .5%= 0.055

X/ R = 10

R = X / 10= 0.00031238 / 10= 0.0.0055

For Connected Loads:

Since X/R is negligible, then Z = X

For Each Connected Load

Z =X = Vs / I b= 0.220 KV / 0.3936 KA

= 0.5589

Calculation for Short Circuit Duty OR Interrupting E/ X Amperes:

For 13.2 KV Distribution and Transformer:

XT = X13.2 KV + XTRANSFORMER= 0.00031238 + 0.055= 0.05531238

I3phase =Interrupting E/X Amperes.

I3phase = IB / XT= 0.3936 / 0.05531238

= 7.12 KA Sym.

Assume that an un limited short circuit current is available at 13.2 KV

system and that Tran s. Z = X, hence, for Line to Groun d Fault, this shortcu twill be used:

ILG = I3phase = Interrupting E/X Amperes.

I3phase = IB / XT= 0.3936 / 0.05531238

= 7.12 KA Sym.


9/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 17 OF 29

IV .

REFERENCES:

o ANSI/IEEE C 62.41-1991 AND ANSI/IEEE C 62.45-1987o UL 1449 EDITION 2o TDX SERIES, Transient Discriminating TVSS, CRITEC/ERICO Technical Manualo Http://www.ERICO.como Westinghouse, Application Data 32-263o Important Information About Electrical Surges And Transient Voltages, SCL

Worldnet, Inc.o http://www.itvss.com/pdf/Transpqind.pdfo http://www.erico.com/erico_public/product/tdx.aspo http://www.erico.com/erico_public/general_info/CRITECTNCR011.asp








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 18 OF 29

This document refers to the technical issues conducted on the above-indicated project for the

preparation of feasibility study by the proponent.

o Technical Issues Surrounding TVSS DevicesTransient voltage surge suppression has been essential ever since the modern

electricity distribution system was put in place. For many years the effect of transientvoltage surges was not recognized even though equipment damage did occur in

many cases. This is especially the case over the last ten years, as mains poweredelectronic equipment has become much more sophisticated and susceptible to

transients. In addition, although the number of power outages is lessening, transientsurges have increased, as have the effects of harmonic distortion on the supply.

o Transient DefinitionAn electrical transient is a temporary excess of voltage and/or current in an electrical

circuit, which has been disturbed. Transients are short duration events, typicallylasting from a few thousandths of a second (milliseconds) to billionths of a second(nanoseconds), and they are found on all types of electrical, data, and

communications circuits

o Sources of Transients:o I n te rna l l y Gene ra ted T rans ien ts :

Up to 80% of transients are generated from internal sources suchas inductive load switching and normal equipment operationscausing:

o Cumulative damage,o Premature equipment failure ando Data losses, system reset, and down time.

o External ly Generated Transients: At least 20% of transients are generated from external sources

such as lightning and power company grid switching. Possiblycausing:

o Catastrophic equipment failure,o Immediate operation shutdown,o Long term disruption of business ando Expensive equipment repair and replacement costs.
http://www.erico.com/http://www.itvss.com/pdf/Transpqind.pdfhttp://www.erico.com/erico_public/product/tdx.asphttp://www.erico.com/erico_public/general_info/CRITECTNCR011.asphttp://www.erico.com/erico_public/general_info/CRITECTNCR011.asphttp://www.erico.com/erico_public/product/tdx.asphttp://www.itvss.com/pdf/Transpqind.pdfhttp://www.erico.com/


10/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 19 OF 29

oType of Transients:

Transients can be split into two types:

o Impulse, large voltage and current over a short duration i.e. lightningstrike.

o Oscillating, lower value voltage and current but over much longer timeperiod (up to 50 times that of lightning strike), e.g. photocopiers, SCRcontrolled equipment, inductive load switching.

Up to 80% of transient surges are generated within a company's own site or

close by. Two examples serve to i llustrate this statistic.

Firstly, tests have shown that a twin four-foot fluorescent light fitting cangenerate 24 x 1200volt transients when it is switched off.

Secondly, just imagine a high tech data storage company geographically close

to and on the same power distribution branch as Fred doing some arc weldingin his garage. The potential repercussions are obvious, resulting in equipmentfaults that can range from temporary glitches to the evaporation of

components, contacts and PCB track.

Transient surge can infiltrate your equipment by various routes:

o Direct Coupling: Caused by lightning strike, or faults on powerdistribution cables.

o Inductive Coupling: Caused by electromagnetic field generated whenlightning hits tall objects such as trees.

o Capacitive Coupling: Caused by lightning strikes to building lightningconductors.

o Resistive Coupling: Caused by ground strikes raising the groundvoltage, which, in turn, causes large potential differences betweenearth points.

The most commonly discussed transient voltage surge is a lightning strike,

although a lightning strike often comprises up to 20 strikes. Both cloud tocloud and nearby ground strikes produce electrical field voltages of hundreds

to thousands of volts per meter. A cloud-to-cloud flash can induce a surge of7,000 volts per meter in power and/or telephone cables and 70 volts permeter a mile away.

An incidence of two strikes per square mile per year would seem to be anaverage figure. As a result of lightning activity, a power surge of between 10-20,000 volts could reach your building. However the maximum normally

considered is 6000 V, with currents up to 3,000 A appearing at your buildingmain power distribution board.








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 20 OF 29

The impedance of the cabling installed on site limits the amount of currentthat reaches your equipment. The main low impedance bus bar could carry

the full 3000A, but the 30 A twin and earth feeding a spur presents a muchhigher impedance that will limit the current to around 200 A for the sametransient. Inevitably, insulation breakdown in cabling, mcbs etc. will limit the

level of transient surge voltage wi thin the building wiring.

The effect of a transient surge on a circuit is not only dependent on size butalso where it hits on the AC cycle. A 200 V transient appearing on the sine

wave at zero crossovers will have little effect but the same transientappearing on the peak of the sine wave will add 200 V to the peak value of

the sine wave value. In this example, the load will be subjected to a voltageof 525 Vac. And remember, transient surges can be positive or negative

going.

Calculating the actual effect of a transient over-voltage can be done by

looking at the way a capacitor or inductor responds to it. In a capacitor any

rapid change across the capacitor will produce a large current, which isdependent on the size of capacitor and rate of voltage change. Its effect canbe expressed by the following formula: I = C dv/dt. A rapid change in current

in an inductor will cause a large transient voltage to be generated, which canbe calculated using the formula -V = L di/dt.

Two numbers normally express the shape o f a transient surge:

o Impulse: the first being the rise time and the second being theduration, i.e. 8 x 20 microseconds.

o Oscillatory: the first being the rise time the second being thefrequency, 0.5/100 microseconds/kHz.

In the real world your equipment, and therefore any TVSS devices, will seefar more longer duration transient surges than the short ones caused by

lightning. But, of course, we must test for both. For short duration testing wewould apply up to a 6kV, 1.2/50 voltage wave form into an open circuit with

the TVSS device across it.

Here, the voltage reaches 90% of its peak in 1.2us and then decays to 50%of its value in 50us. A 3kA current waveform that reaches peak current after8 microseconds and decays to 50% of that value in 20us is applied to a short

circuit with TVSS attached.

For long duration testing, the waveform will have a peak value of 2kV with arise time of 10us and a duration 1000us. The current waveform has a peak of

2.5kA with the same rise and duration times (10/1000us).


11/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 21 OF 29

oThree Basic Types of TVSS:

In essence, a TVSS device is a component that limits the amount of energy froma transient and, as a result, protects your equipment from damage. There arethree basic types:

Gas Discharge Tube (GDT)

These devices modify an uncontrolled flashover by the use of specially

designed electrodes in a tube containing one or more gasses under pressure.Altering one or more of the elements that make up the GDT can achieve

different breakdown voltages achieved, ranging from 100V to several kV. Inaddition, the slope of the applied voltage has an effect on the breakdown

voltage. Once the GDT fires it becomes a crowbar device that can reduce theapplied voltage down to a few tens of volts in nanoseconds, and is able tohandle surge currents of 20kA or more for a single transient surge.

However, there are two points that must be considered when consideringusing gas discharge tubes: - Even though the tube may have a lowbreakdown rating it will still require 600-800V to strike when a confronted

with a steep leading edge waveform. Once break down has been achieved thearc may not be extinguished once the transient has passed, if the normal line

voltage exceeds 10-15volts. This effect can distort the normal signal on theline and, if the circuit can provide enough current, could destroy the tube. As

a result of these considerations, GDT devices are far more effective whenused in conjunction with lower clamping devices.

Metal Oxide Varistor (MOV)

Metal Oxide Varistors are made from zinc oxide fragments compressed under

very high pressure. Their resistance decreases as the applied voltageincreases, which should therefore provide excellent clamping of an appliedtransient surge. Although their in circuit response time is 35-50 nanoseconds,

the resistance characteristic is non linear, and the volt drop across the MOVwill increase dramatically as the current Increases.

This non linearity means that when the device is subjected to a large

transient current surge the clamping voltage will increase and can exceed thelevel at which damage can occur to equipment. In addition, long durationsurge currents will cause the device to destabilize. On the plus side, MOVs are

cheap and can handle large currents. However be careful of claims of very

high current capacities that don't also include the voltage protection level.The life expectancy of an MOV is dependent on both the size and quantity ofapplied transient surges, because they age as the zinc oxide particles weaken

after conducting current. A 20mm MOV specification may claim 6500Amppeak surge current, but this will only be for a single 8/20us short circuit

transient. As the peak current of the 8/20ustransient surge decreases, the








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 22 OF 29

quantity of surges the MOV can take will increase. However a single longduration current waveform of much lower peak current value can cause the

MOV to fail. This could be as low as a 100-200A surge current pulse lasting1ms.

Silicon Avalanche Diode (SAD)

These semi-conductors are similar to very large junction zener diodes,responding very rapidly to transient surges with an in circuit response time

equal to or less than 5 nanoseconds (dependant on circuit inductance) andcan therefore handle the rapid rise time of a transient surge much better than

an MOV. Clamping voltages range from a few volts to several hundred volts.However, the clamping voltage selected should be as close to the peak value

of the sine wave as possible without continually conducting.

Unfortunately this subjects the device to high levels of transient energy that

single diodes cannot dissipate, requiring numerous diodes, so that the energy

can be dissipated without the devices sacrificing themselves. Inevitably thismeans that the suppressor will be larger and more expensive than usingMOVs. Unlike MOVs, silicon avalanche diodes can conduct their maximum

current without any increase in clamping voltage. Nor will they degrade inuse, as long as their parameters are not exceeded.


12/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 23 OF 29

oSELECTION IN THE TYPE OF TVSS TO BE USED

CONSIDERATIONS:

There are many parameters to be considered, when designing an effective

suppression unit. We have opted to select:

I. A combination of SADs and MOV because SADs alone would be far toocostly for a unit designed to take the same amount of energy. The silicon

avalanche diodes provide a very rapid response while the metal oxidevaristors give us the large current capacity. In addition the presence of

SADs will prevent the clamping voltage rising, as the MOVs take morecurrent. In principle, this sounds an ideal combination, although careful

consideration must be given to the response curves of the two devices.Because the SADs react so much quicker, there is a danger that they will besubjected to over current before the MOVs start to conduct. Consequently, it

would be inadvisable to use only a few SADs in conjunction with the MOVs,

to reduce costs further.II. Technology enhancing the features of I.III. Another advanced technology than I.o TVSS Manufacturers And Technologies

1. CRITEC/ERICO

Conventional SPD technologies utilize metal oxide varistors (MOV) and/or

silicon avalanche diodes (SADs) to clamp or limit transient events. However,these devices are susceptible to sustained 50/60 Hz mains over-voltageconditions, which often occur during faults to utility system. Such occurrences

present a significant safety hazard when the suppression device attempts to

clamp the peak of each cycle on the mains over-voltage. This condition cancause the device to rapidly accumulate heat and in turn fail, with thepossibility of creating a fi re hazard.

Transient Discriminating (TD) Technology

ERICO has a proprietary technology that provides the first quantum leap in

transient suppression for mains powered equipment. It offers a new level ofsafety and reliability, yet retains optimum protection levels critical forelectronic business.








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 24 OF 29

Benefits of Transient Discriminating (TD) Technology

o Resilient to over-voltage events, yet provides un-compromisedprotection levels

o Continued protection even after severe over-voltage events (up to480Vrms) - i.e. can sustain an over-voltage event and continue towork without interruption or replacement being required

o Robust design ensures long service life in real world conditionsOvervoltages can occur for a number of reasons, including:

o Poor regulation of the distribution systemo Faulty or incorrectly set transformer tap chargeso High N-E voltages adding to the stress of Ph-E connected protection

deviceso Wiring faults such as open neutrals on unbalanced three phase

systemso Concerns about the safety of surge protection devices (SPDs) with

regard to over-voltages have been addressed in recent standards.ERICO's TDS products are compliant with UL1449 Edition 2 abnormal

over-voltage limits.

Features

o Extreme Over-Voltage Withstando Low Let-Through Voltageo Long Lifeo Multipulseo Shockguard - proprietary encapsulation compound to minimize

mechanical stress within the surge suppressoro Multi-Stageo Safety Approved - independently tested by Underwriters Laboratory in

USA and meets requirements of latest edition of UL1449

o Multi-Source - designed & tested to protect against all transientsources including li ghtning transients and spikes and glitcheso Extra Fast Transient Wi thstand


13/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 25 OF 29

How Does TD Technology Work?

The core of this new technology is an active frequency discrimination circuitthat discriminates between the slower mains voltages and the higher speed

transients. When transient frequencies are detected, the patented TransientDiscriminating (TD) Quick-Switch technology "switches in" robust surge

protection devices (SPD's) to l imit the transient condition.

The frequency discrimination circuit controlling the Quick-Switch ensures thatthe device is virtually immune to the effects of the 50/60Hz-sustained over-

voltages, allowing fault voltages of up to 480Vrms to be withstood.

To meet such stringent TOV testing, traditional technologies often use thermaldevices or over-current devices such as fuses to permanently disconnect allprotection from the circuit. In contrast, TDS technology remains operative

after such over-voltages, continuing to provide safe reliable transient

protection. After an over-voltage event TDS technology device can be reliedon to still be providing your critical equipment with transient protection!

Where Should TD Technology Be Used?

TD technology is recommended:

o For any site where the voltage is known to exceed the nominal ratingby more than 15%

o Where the possible catastrophic failure of traditional technologies dueto unexpected over-voltage events cannot be tolerated

TD technology is available from ERICO in both shunt and series protectionproducts with a number of surge and voltage ratings available. Theseinclude:

TDS-Movtec

- Shunt Surge Diverters (for point-of-entry primary protection)TDS-SRF

- Surge Reduction Filters (for protection of strategic/critical equipmentTDS-DINLINE Shunt Diverters

-or secondary power protection








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 26 OF 29

2. IT Protectors(Innovative Technology)

MEM offers two levels of protection: Threshold Suppression Network (TSN), or ActiveTracking Network (ATN). The Active Tracking Network (ATN) is designedspecifically to address the large number of switching generated transient events

present in all our electrical distribution systems in order to protect the most sensitiveelectronic systems upon which we rely in our daily business activities. The selection

of which option to use will be determined by the nature and the value of theequipment to be protected. The effect on the system of the different devices is

illustrated below.

Unsuppressed System:

If we consider a single cycle of the 50Hz AC sine wave, at 90 the connected loadequipment expects to see the peak voltage of the sine wave, at 180, the zero-

crossing point, it expects to see 0 volts, and at 270, minus peak voltage. If we now

apply the 2000 volt test waveform at 180 onto an unsuppressed system, instead ofzero volts at this instant, the load equipment may be exposed to a peak overvoltageof 2000 vol ts. Obviously this has the potential to damage unprotected equipment.


14/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 27 OF 29

Threshold Suppression Network (TSN):

This provides the best suppression of high-energy impulse generated transients andsuits a wide range of applications. As the name suggests, the suppressor has setthresholds above and below the peaks of the AC sine wave. Any deviation above this

results in the device responding to clamp the overvoltage as close as possible to thisthreshold. With the same applied 2000 volt waveform at 180, the measured limiting

voltage in this test may be as high as 600 volts line to neutral. Whilst this offersexcellent protection for the majority of our load equipment, and certainly all electro-

mechanical devices, some particularly sensitive and critical load equipment may stillbe affected.








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 28 OF 29

Active Tracking Network (ATN):

In addition to the fixed threshold, these systems now also has thresholds which trackthe AC sine wave, and are able to respond to any transient activity on the system atwhatever polarity and phase angle it occurs. Typically this will reduce the same 2000

volt test waveform at 180 to around just 70 volts line to neutral. Clearly this nowoffers the best available level of protection for the load equipment, and is suitable for

protecting the most sensitive electronic equipment such as PLC control systems, datacommunications equipment,

Active Tracking Network (ATN) is the most effective transient suppression circuitavailable. ATN responds immediately to transients at all phase angles, polarities

and across a wide range of frequencies, providing the best protection available forcritical and sensitive loads. ATN provides the lowest let-through voltage levels on

the widest range of transient types.

The UL 1449 Second Edition and UL1283 listed models that utilize the ATN circuit is

expressly designed to suppress switching generated ringing transients, which are the

most common events in electrical systems. The ability to cover a wide range of


15/15








C.L. Asas,

REE

JA Bation,

REE

O. Geonzon,

REE

PROJECT

PROPONENT

GROWTH POLYGON JAB



SUMICON

PAGE 29 OF 29

differing transient wave shapes and frequencies gives the ATN circuit a clearadvantage over other designs on the market today.

The Benefits of Active Tracking Network (ATN)

When selecting a surge suppressor, one of the primary considerations must be the'measured limiting voltage' of the device. This is defined as 'the actual amount of

peak voltage that the load equipment is exposed to AFTER the surge suppressiondevice operates', and is the critical factor in determining whether damage will occur

to the protected equipment. In order to compare the performance of differenttransient voltage surge suppressors, it is necessary to establish uniform testing

criteria, and to test under strictly controlled conditions. Whilst it is not possible topredict the exact nature of transient activity in any given installation, much research

has been undertaken to establish 'typical' transient conditions experienced within theelectrical environment. The ANSI/IEEE C62 standards define a number of such'typical' events, together with a uniform set of test criteria in order to enable us to

provide such comparisons.

Switching on or off all internal loads generates around 80% of the transient activitywithin our electrical environment. Whilst these events will generally be of lower

magnitude than many external events, such as lightning or major power systemevents, they are still likely to cause problems with many of our sensitive electronic

systems. Typical problems include premature equipment failure and data relatedproblems such as PLC program difficulties and data communication errors.

ANSI/IEEE C62.41 typifies these lower level switching generated transients as theCategory A1 100Khz ring wave, tested at 2000 volts and 67 amps, with the test

conducted at 180 on the sine wave.

TVSS Installation Tech Study

Documents

Transcript of TVSS Installation Tech Study