Lightning Protection Forum Shanghai June  Impulse current testing ichael Gamlin Haefely Test AG Basle Switzerland Abstract IEC time parameter definitions for i pulse currents are explained and overvi

Lightning Protection Forum Shanghai June Impulse current testing ichael Gamlin Haefely Test AG Basle Switzerland Abstract IEC time parameter definitions for i pulse currents are explained and overvi - Description

The diffe r ent impulse currents such as exponential current m pulses ECI lightning current impulses LCI and rectangular current impulses RCI are analytically described by their simplified circuit di gram The generation of the ligh ning current imp ID: 24900 Download Pdf

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Lightning Protection Forum Shanghai June Impulse current testing ichael Gamlin Haefely Test AG Basle Switzerland Abstract IEC time parameter definitions for i pulse currents are explained and overvi

The diffe r ent impulse currents such as exponential current m pulses ECI lightning current impulses LCI and rectangular current impulses RCI are analytically described by their simplified circuit di gram The generation of the ligh ning current imp

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Lightning Protection Forum Shanghai June Impulse current testing ichael Gamlin Haefely Test AG Basle Switzerland Abstract IEC time parameter definitions for i pulse currents are explained and overvi




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Presentation on theme: "Lightning Protection Forum Shanghai June Impulse current testing ichael Gamlin Haefely Test AG Basle Switzerland Abstract IEC time parameter definitions for i pulse currents are explained and overvi"— Presentation transcript:


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Lightning Protection Forum Shanghai June 2004 Impulse current testing ichael Gamlin Haefely Test AG, Basle, Switzerland Abstract: IEC time parameter definitions for i pulse currents are explained and overview of the IEC standards 60060 1, 60099 4, 61643 1 and 61312 1 in re gards to impulse curr ent testing is given. The diffe r- ent impulse currents such as exponential current m- pulses (ECI), lightning current impulses (LCI) and rectangular current impulses (RCI) are analytically described by their simplified circuit di gram . The generation of the ligh ning current impulses

(LCI) is more detailed explained and the impulse current sy s- tem of the Shanghai Metro ogy Institute delivered by the Haefely AG is introduced especially in regards of lightning current impulse testing. 1. Introduction The IEC tandards 60060 1, 60099 4, 61643 1 and 61312 1 specify param ter tolerances for the diffe ent expon ential current impulses (ECI), rectangular cu r- rent impulses (RCI) and lightning current impulses. IEC 61312 1 standard gives a guideline how a ligh t- ning cur rent impulse (LCI) for test purposes can be achieved. 2. ime parameter definitions for impulse cu rents

according to IEC standards 2.1. Exponential current impulse (ECI) Figure 1. Time parameter ECI Front time ime to half value Virtual origin 2. . Rectangular current impulse ( CI) Figure 2. Time parameter RCI Duration of peak of a rectangular impulse Total duration of a rectangular impulse cu rent 2.3. Current ris Figure arameter current rise 90% I 10% 90% 10% 3. Overview of impulse current definitions cording to IEC standards 3.1. IEC 60060 : High Voltage Test Tec niques; Part 1: General definitions and test r quirements IEC 60060 1 defines several ponential current m- pulses as well as several

rectangular current impulses by time parameters, peak values, polarity reversal and the permitted tolerances (see Fi ure 4.)
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Lightning Protection Forum Shanghai June 2004 3.2. IEC 600 99 4: High Voltage Test Te niques; Surge arrestors; Part 4: Metal oxide surge arre s- tors without gaps for a.c. systems IEC 60099 4 defines several exponential and recta n- gular current impulses by time parameters, peak va l- ues, polarity reve sal, needed energy and the permitted tolerances (see Fi ure 5.). Compared with IEC 60060 1 the tolerances for the time param ter for ECI varies.

Furthermore the RCI is fined by time parameters and energy mand for the test object . To simulate service conditions of an arrestor 4/10, 8/2 0, 30/80 and long duration cu r- rent im pulses are combined with the rated Figure 4. IEC 60060 1 impulse current definitions Figure IEC 60099 4 impulse current definitions
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Lightning Protection Forum Shanghai June 2004 arrestor AC vol age (operating duty test ODT). 3.2. IEC 61312 1 (Annex C): Protection against lightning electromagnetic impulse , Simul tion of the lightning current for test purpose , First ligh t- ning stroke Simulation

parameters: Peak current: peak Charge: Specific energy: Current rise: = 90% I 10% , = 90% 10% IEC standard 61312 1 (Annex C) splits up the first lightning stroke current into a high energy po tion and a fast rise time portion. Both por tions can be applied independent ly or in combination 3.2 .1 . IEC 61312 1 (Annex C): High energy po tion “The parameters peak , , and W/R with their tole r- ance s are to be obtained in the same impulse. This can be achi eved by an approximately exponentially deca ing current with in the range of 350 s. (see figure 6.) 3.2 .2 . IEC 61312 1 (Annex C): Fast rise

time po r- tion “The simulation conducted in accordance with this method covers the rate of rise of the current of short duration strokes D i / t. The tail of the cu rent is of no consequenc e for this kind of sim lation. (see figure .) 4. Simplified analytical description of different impulse currents .1. Simplified principle circuit diagram for exp o- nential current impulses (ECI) Figure 8. Simplified circuit diagram ECI dt dt Figure IEC 61312 14 (Annex C) igh energy porti Figure IEC 61312 14 (Annex C) Fast rise time po tion
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Lightning Protection Forum Shanghai June 2004

0.00 0.50 1.00 1.50 2.00 2.50 3.00 10 R / R 0 peak in 4.1.1 . Aperiodic damped circuit (1/<20 wave shape) Figure 9. normalized aperiodic damped ECI Above formulas show that the higher the damping (R ?) the shorter is the rise time (T ?) but the lower is the current peak (I peak ?) and the longer is the time to half value (T ?) Figure 10 Rise time versus damping for aperiodic damped ECI 4.1.2 . Periodic damped circuit (4/10, 8/20, 30 /80, switching current) Figure 11 normalized periodic damped ECI 4. 2. Simplified principle circuit diagram for re c- tangular current impulses (RCI) An RCI

impulse generator consists of 8 to 12 distri b- uted constant impulse generat ors Figure 12 Distributed constant impulse generators for RCI The formula below describes the relation between the used lattice network and the duration of the peak T 90% (or T ). Figure 13 ectangular current impulse CI, lass 5 arrestor, rated = 12 kV, 60 kJ ln( ), sinh( criterion damping peak peak => arctan( ), sin( criterion damping peak 12 .. tot tot tot tot 90 1 ms 2 ms 3 ms 4 ms 5 ms 6 ms 7 ms 100 A 200 A 300 A 400 A 500 A 600 A 700 A RCI Ipk : 623.919 A Td : 3.500 ms Tt : 4.318 ms 0.0 0.2 0.4 0.6 0.8 1.0 10 20

30 40 50 60 70 80 90 100 t in i(t) / I max -0.20 0.00 0.20 0.40 0.60 0.80 1.00 10 20 30 40 50 60 70 80 t in i(t) / I max
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Lightning Protection Forum Shanghai June 2004 Figure 13 Impulse current system SSGA 100 150 (100 kV, 150 kJ) for arrestor testing acc ording to IEC 60099 4 with ECI, RCI and ope ating duty testing 4.3. Simplified principle circuit diagram for lig t- ning current impulses (LCI) Figure 14 Simplified circuit diagram L CI Figure 15 normalized simplified LCI 5. Lightning current impulse generation (LCI, “10/350”) 5.1. Detailed LCI circuit diagram Figure 15 De

tailed circuit diagram L CI 5.2. Function principle LCI circuit By the ignition of the main spark gap the energy stored in the charging capacitors capacitance is transferred to the external inductance . Shortly e- fore the pulse current reaches its peak value the crow bar spark gap 2 is triggered by the impulse voltage ge erator. To achieve a fast rise time of about a few hu dred ns for the impulse voltage generator current an extremely low inductive peaking circuit has to be integrated. The voltag e drop of this fast di s- charge current across the main circuit inductance finally ignites the

crowbar spark gap 3 and the crowbar switch is closed. A crowbar switch is a sp e- cific spark gap arrangement being able to be triggered under virtually no volta ge condition. To ful fil the fast rise time portion the external indu c- tance value L has to be chosen quite low (some H) whereas for the high energy portion the external n- ductance value has to be in the range of some ten H. As soon as the crow bar switch is closed the time to half value is determined by the time constant (L +L crowbar )/(R +R crowbar +R DUT ). All com nent in this external circuit (crowbar, external inductance)

must have a low resistive de sign and the current is mea s- ured by a Rogowski coil and not by a shunt. Due to the inherent crowbar inductance crowbar t o- gether with the charging capacitors capacit ance an oscillation closely after the current peak occurs as to be seen in figure 16 and 17. To insure reproducible LCI impulse the controls of the main impulse current circuit and the impulse voltage generator must work together in a master/slave mode. The benefit of the master/slave mode is that a delay time can be adjusted and a triggering is only possible when both circuits are charged up. ),

sin ). 0.2 0.4 0.6 0.8 500 1000 1500 2000 t in i(t) / I max
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Lightning Protection Forum Shanghai June 2004 Figure 16 Fast rise time portion LCI Figure 17 nergy portion LCI 5.3. L CI circuit components Figure 18 Impulse current system SSG 200 180 (200 kV, 180 kJ) for SPD testing with ECI and LCI Figure 19 Motorized crowbar electrodes with tungsten copper insertion to nsure a reliable performance Figure 20 Cont ol unit GC 223 for the impulse current circuit (bottom) and crowbar control CBC 220 (top) for adjusting and displaying the crowbar electrode distances Figure 21 Low

resistive , reliable resin cast coil design 1 ms 20 kA 40 kA 60 kA 80 kA 100 kA 120 kA 140 kA CH2 : Shunt:5.000 mOhm Level:100% Sampling:7.500 Ms/s Range:800.0 Vpp Trigger:Level 10% No. 1 LCI Ipk : 107.243 kA di : 85.794 kA dt : 9.887 us di/dt : 8.677 kA/us T1 : 12.359 us T2 : 363.876 us Qs : 46.187 As W/R : 2.647 MJ/Ohm 1 ms 20 kA 40 kA 60 kA 80 kA 100 kA 120 kA 140 kA CH2 : Shunt:5.000 mOhm Level:100% Sampling:7.500 Ms/s Range:800.0 Vpp Trigger:Level 10% No. 20 LCI Ipk : 116.885 kA di : 93.508 kA dt : 9.876 us di/dt : 9.468 kA/us T1 : 12.346 us T2 : 357.878 us Qs : 50.635 As W/R : 3.135

MJ/Ohm
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Lightning Protection Forum Shanghai June 2004 Figure 22 Motorized, low inductive crowbar design with peaking circuit Figure 23 Test chamber with connected SPD ready for testing Figure 24 SPD exploded during LCI testing 6. Technical data impulse current syste m SSGA 200 180 and future exten sion possibil i- tie Wave shape max. current peak max. charging voltage max. load 8/20 200 kA 100 kV 100 m “10/350 100 kA 200 kV 50 m Extension pos sibility by integrating additional damping resistors and external induc ances (metal oxide arrestor testing according to IEC 60099 4)

1/20 30 kA 200 kV = 12 kV 4/10 150 kA 200 kV = 12 kV 30/80 60 kA 100 kV = 12 kV Switching cu rent 3 kA 100 kV = 12 kV Author address: Michael Gamlin Manager Engineering HVT Haefely Test AG, Lehenmattstr. 353 CH 40 52 Basle, Switzerland Email: gamlin.michael@haefely.com