Overvoltage Protection and Insulation Coordination

Overvoltage Protection and Insulation Coordination in Power Systems

Prof. Dr.-Ing. Volker Hinrichsen Dipl.-Ing. Simona Feier-Iova Technische Universität Darmstadt High Voltage Laboratories © Siemens

Fachgebiet Hochspannungstechnik

Overvoltage Protection and Insulation Coordination / Chapter 1

-1-

What is Insulation Coordination? Definition Definition in in IEC IEC 60071-1 60071-1

Definition Definition in in IEEE IEEE 1313.1 1313.1



-2-

Fundamentals of Insulation Coordination 5

Magnitude of (over-)voltage / p.u.

Possible voltages without arresters 4

Withstand voltage of equipment 3

2

1

Voltages limited by arresters 0 Lightning overvoltages (Microseconds)

Switching overvoltages (Milliseconds)

Temporary overvoltages Highest voltage of equipment (Seconds) (Continuously)

Time duration of (over-)voltage



-3-

What is Insulation Coordination? Procedure of insulation coordination [THI-01] Three Three elements elements are are involved involved in in the the insulation insulation coordination coordination discipline, discipline, namely: namely: •• the the study study of of the the "stresses", "stresses", both both electrical electrical and and environmental, environmental, acting acting on on the the equipment equipment insulation. insulation. This This is is usually usually performed performed by by calculations calculations or or field field measurements; measurements; •• the the study study of of the the "strength" "strength" (dielectric (dielectric withstand withstand characteristics) characteristics) of of the the insulation insulation (both (both new new and and aged) aged) when when submitted submitted to to such such stresses, stresses, taking taking into into account, account, when when applicable, applicable, the the effect effect of of the the environmental environmental stresses stresses (pollution, (pollution, rain, rain, snow, snow, ice, ice, atmospheric atmospheric conditions conditions at at large large altidudes), altidudes), including including the the study study of of the the "test "test and and measurement measurement techniques" techniques" which which are are employed employed to to assess assess such such strength. strength. The The strength strength is is determined determined by by calculations, calculations, based based on on suitable suitable discharge discharge models, models, and/or and/or by by laboratory/factory laboratory/factory tests, tests, on-site on-site tests tests and and in-service in-service measurements measurements (diagnostics); (diagnostics); •• the the assessment assessment of of the the insulation insulation performance performance (usually (usually expressed expressed in in terms terms of of risk risk of of failure) failure) in in the the considered considered situation situation of of stresses stresses and and strength, strength, including including the the selection selection and and application application of of "protective "protective devices devices and and techniques", techniques", to to establish establish the the final final insulation insulation design design fulfilling fulfilling the the specified specified requirements. requirements. This This may may be be based based on on "deterministic" "deterministic" or or "statistical" "statistical" approach. approach. Fachgebiet Hochspannungstechnik


-4-

Literature (1) [BAL-04-1]

G. Balzer Power Systems, Part 2 Chapter 4: Insulation coordination Script TU Darmstadt, 2004

[BAL-04-2]

G. Balzer Elektrische Energieversorgung, Teil 2 Kapitel 4: Isolationskoordination Skript der TU Darmstadt, 2004

[CIG-73]

CIGRE W.G. 13-02 Switching overvoltages in EHV and UHV systems with special reference to closing and reclosing transmission lines ELECTRA 30 (1973) pp. 70-122

[CIG-79-1]

CIGRE WG 33.02 Phase-to-phase Insulation Co-ordination: Part 1: Switching overvoltages in three-phase systems ELECTRA 64 (1979) pp. 138-158

[CIG-79-2]

CIGRE WG 33.03 Phase-to-phase Insulation Co-ordination Part 2: Switching impulse strength of phase-to-phase external insulation ELECTRA 64 1979, pp. 158-181



-5-

Literature (2) [CIG-79-3]

CIGRE WG 33.06 Phase-to-phase Insulation Co-ordination Part 3: Design and testing of phase-to-phase insulation ELECTRA 64 1979, pp. 182-210

[CIG-79-4]

CIGRE TF 33-03.03 Phase-to-phase Insulation Co-ordination Part 4: The influence of non-standard conditions on the switching impulse strength of phase-to-phase insulation ELECTRA 64 1979, pp. 211-230

[CIG-91]

CIGRE WG 33.01 Guide to procedures for estimating the lightning performance of transmission lines, CIGRE technical brochure No. 63, 1991 buch_020.pdf

[CIG-92]

CIGRE WG 33-07 Guidelines for the evaluation of the dielectric strength of external insulation, CIGRE technical brochure No. 72, 1992 buch_019.pdf

[DOR-81]

H. Dorsch Überspannungen und Isolationsbemessung bei Drehstrom-Hochspannungsanlagen Siemens AG, Erlangen, 1981 (ISBN 3-8009-1325-9)



-6-

Literature (3) [ERI-88]

A.J. Eriksson, K.-H. Weck Simplified procedures for determining representative substation impinging lightning overvoltages, CIGRE report 33-16, 1988

[ETG-93]

ETG-Fachbericht 49 ETG-Tage '93: Isolationskoordination in Hoch- und Mittelspannungsanlagen vde-Verlag GmbH Berlin, Offenbach (ISBN 0341-3934)

[FGH-78]

FGH Technischer Bericht 1-240 Isolationskoordination auf der Grundlage der neuen DIN/VDE-Bestimmung 0111 FGH, Mannheim, Juli 1978

[HIL-99]

A. R. Hileman Insulation Coordination for Power Systems Marcel Dekker, Inc., New York, Basel, 1999

[HIN-00]

V. Hinrichsen Metalloxidableiter: Grundlagen Siemens AG Berlin, 1. Auflage 2000 AbleiterBuch.pdf

[HIN-01]

V. Hinrichsen Metalloxidableiter: Grundlagen Siemens AG Berlin, Edition 1, 2001 ArresterBook.pdf



-7-

Literature (4) [HIN-03]

V. Hinrichsen Latest Designs and Service Experience with Station-Class Polymer Housed Surge Arresters World Conference on Insulators, Arresters & Bushings Marbella (Málaga), Spain, November 16-19, 2003, Proceedings pp. 85-96 pub_048.pdf

[KIN-05]

V. Hinrichsen Latest Testing Requirements and Emerging Standards for Transmission Line Arresters World Conference on Insulators, Arresters & Bushings Hong Kong, November 27-30, 2005 inmr_2005_paper.pdf

[KIS-84]

I. Kishizima, K. Matsumoto, Y. Watanabe, New facilities for phase switching impulse tests and some test results, IEEE PAS TO3 No. 6, June 1984 pp. 1211-1216.

[KOE-93-1]

D. König, Y. N. Rao Teilentladungen in Betriebsmitteln der Energietechnik vde-Verlag, Berlin, Offenburg, 1993, ISBN 3-8007-1764-6

[KOE-93-2]

D. König, Y. N. Rao Partial discharges in Power Apparatus vde-Verlag, Berlin, Offenburg, 1993, ISBN 3-8007-1760-3



-8-

Literature (5) [PAR-68]

L. Paris, R. Cortina Switching and lightning impulse discharge characteristics of large air gaps and long insulation strings, IEEE Trans on PAS, vol 87, No. 4, April 1968, p. 947-957

[RUD-99-1]

R. Rudolph, B. Richter Dimensioning, testing and application of metal oxide surge arresters in medium voltage networks 3rd Edition, 1999, ABB Switzerland, 26 pages (also available in German) application_guide_medium_voltage_networks.pdf

[RUD-99-2]

R. Rudolph, B. Richter Bemessung, Prüfung und Einsatz von Metalloxid-Ableitern in Mittelspannungsnetzen ABB Schweiz AG, Wettingen (CH), 3. Auflage 1999 Anwendungsrichtlinien_Mittelspannung.pdf

[THI-01]

L. Thione Insulation coordination in electrical power systems – theory and application Tutorial, ALPI, Milan, 2001 (www.alpiass.com) buch_018.pdf



-9-

Literature (6) [WEC-07]

K.-H. Weck Standardization of insulation withstand levels for UHV systems in IEC TC 28 „Insulation co-ordination” IEC/CIGRE UHV Symposium Beijing 18-21 July 2007, report 5-4 5-4_KHWeck.pdf

Overview on CIGRE publications (very interesting!): Cigré Catalogue of Publications 01/07/2005 CATALOGUE_PUBLICATIONS_2005.pdf



- 10 -

Standards (1) IEC 60071-1, Edition 8.0 (2006-01) Insulation co-ordination – Part 1: Definitions, principles and rules IEC 60071-2, Third Edition (1996-12) Insulation co-ordination – Part 2: Application guide IEC/TR 60071-4, First Edition (2004-06)

Insulation co-ordination - Part 4: Computational guide to insulation co-ordination and modelling of electrical networks IEC 60099-4, Ed. 2.1, 2006-07 Surge arresters – Part 4: Metal-oxide surge arresters without gaps for a.c. systems IEC 60099-5, Ed. 1.1, 2000-03 Surge arresters – Part 5: Selection and application recommendations DIN EN 60071-1, 1996-07 Isolationskoordination - Teil 1: Begriffe, Grundsätze und Anforderungen (IEC 60071-1:1993); Deutsche Fassung EN 60071-1:1995 DIN EN 60071-2, 1997-09 Isolationskoordination - Teil 2: Anwendungsrichtlinie (IEC 60071-2:1996); Deutsche Fassung EN 60071-2:1997 IEEE 1313.1-1996 IEEE Standard for Insulation Coordination—Definitions, Principles, and Rules Fachgebiet Hochspannungstechnik


- 11 -

Standards (2) IEEE 1313.2-1999 IEEE Guide for the Application of Insulation Coordination IEEE C62.11-2005 IEEE Standard for Metal-Oxide Surge Arresters for AC Power Circuits (> 1 kV) IEEE C62.22-1997 IEEE Guide for the Application of Metal-Oxide Surge Arresters for Alternating-Current Systems



- 12 -

Organization 1

18.10.2007

Lecture 1

2

25.10.2007

Lecture 2

3

01.11.2007

Lecture 3

Voltage stresses

08.11.2007

cancelled

in power systems

4

15.11.2007

Lecture 4

5

22.11.2007

Lecture 5

Traveling waves

6

29.11.2007

Lecture 6

Overvoltage protection incl. protective distance

7

06.12.2007

Lecture 7

Dielectric strength (incl. gap factors,

8

13.12.2007

Lecture 8

pollution, rain, parallel insulation, aging)

9

20.12.2007

Lecture 9

Insulation coordination

27.12.2007

Christmas holidays

03.01.2008

Christmas holidays

10

10.01.2008

Lecture 10

Insulation coordination

11

17.01.2008

Lecture 11

Calculation Examples

12

24.01.2008

Lecture 12

13

31.01.2008

Lecture 13

Test procedures; condition monitoring (life time aspects, partial discharges, non-conventional approaches)


Introduction


- 13 -

Organization Examination Examination Exclusively oral

Exercises Exercises None; but calculation examples in the lecture

Script Script Slides will be available for download www.hst.tu-darmstadt.de User: studentiso PW: isows0708



- 14 -

Equipment

System

Insulation Coordination - Principles


System voltages

Overvoltage protection devices

stress versus strength

Environment

Dielectric strength Overvoltage Protection and Insulation Coordination / Chapter 1

- 15 -

Insulation Coordination - Principles • Voltages of the system – Nominal voltage Un » rounded value for characterizing the system » 10 kV - 20 kV - 110 kV - 220 kV - 380 kV – System voltage » voltage at which the system is being operated » around the nominal value, but not constant – Highest system voltage Us » highest operating voltage between phases under normal conditions » 12 kV - 24 kV - 123 kV - 245 kV - 420 kV (IEC 60038)

• Voltages of equipment – Highest voltage for equipment Um » highest voltage between phases for which the insulation is designed » 12 kV - 24 kV - 123 kV - 245 kV - 420 kV (IEC 60071-1) Fachgebiet Hochspannungstechnik


- 16 -

Insulation Coordination - Principles • Overvoltages – voltages exceeding the peak value of the highest system voltage – various amplitudes and shapes depending on » system configuration (grid size, degree of meshing, etc.) » origin of overvoltage (failure, switching, lightning strike etc.)

• Dielectric strength of insulation – verified by type test in the laboratory with the help of » standardized test voltages (shape, amplitude) » specified test setups » specified environmental conditions

• Insulation coordination – Determination of interdependence between voltages and overvoltages of the system and necessary test voltages for the equipment in the laboratory



- 17 -

Insulation Coordination - Principles Equipment in the system

Equipment in the laboratory

Variety Variety of of amplitudes amplitudes and and shapes shapes of of overvoltages overvoltages

Standardized Standardized amplitudes amplitudes and and shapes shapes of of test test voltages voltages

Variety Variety of of operating operating conditions conditions and and age age

Standardized Standardized setups setups and and conditions conditions

Variety Variety of of environmental environmental conditions conditions

Standardized Standardized environmental environmental conditions conditions



- 18 -

Insulation Coordination - Principles Insulation phase - ground

bb 1

stressed by voltages between one phase and ground

1

bb 2

2

Insulation phase - phase

3 1

stressed by voltages between two phases

2

Longitudinal insulation

busbar disconnectors

stressed by voltages between same phases of two different systems line

3 Fachgebiet Hochspannungstechnik


- 19 -

Insulation Coordination according to IEC 60071-1 (and 60071-2)



- 20 -




- 21 -


...39 ...39 pages pages in in sum sum

Procedure Procedure for for insulation insulation coordination coordination == 10 10 pages! pages!



- 22 -




- 23 -




- 24 -




- 25 -




- 26 -




- 27 -


...125 ...125 pages pages in in sum sum



- 28 -

Procedure for Insulation Coordination - General The procedure for insulation coordination consists of the selection of a set of standard withstand voltages which characterize the insulation of the equipment.

Range I


Range II


- 29 -

Procedure for Insulation Coordination - General

withstand voltage

Basic difference between ranges I and II

Minimum Minimum of of withstand withstand voltage voltage for for switching switching overvoltage overvoltage

Range Range IIII

gap spacing 3 m

Range Range II

Withstand Withstand voltage voltage continuously gap spacing 0.5 m continuously decreasing decreasing with with time time duration duration of of stress stress

[FGH-78]

peak

time duration of stress Fachgebiet Hochspannungstechnik


- 30 -

Procedure for Insulation Coordination in Four Steps Determination of the representative overvoltages Urp • The representative overvoltages are derived from real service conditions, but have just standardized shapes. • They are determined in amplitude, shape and duration by system analysis, taking into account overvoltage limiting devices.

[IEC 60071-1] Fachgebiet Hochspannungstechnik


- 31 -

Procedure for Insulation Coordination in Four Steps Determination of the coordination withstand voltages Ucw • The coordination withstand voltages are the lowest values of withstand voltages of each overvoltage class, for which the expected low failure rate of the equipment is not exceeded over its full lifetime. • Derived from the representative overvoltages Urp by the coordination factor Kc.

Typical for Germany: 0.1% per year 1 failure in 1000 years

[IEC 60071-1]



- 32 -

Procedure for Insulation Coordination in Four Steps Deterministic Deterministic approach approach

Statistical Statistical approach approach

Assumed Assumed maximum maximum of of representative representative overvoltage overvoltage

Statistical Statistical distribution distribution of of representative representative overvoltages overvoltages Determination Determination of of failure failure probability probability of of insulation insulation

Multiplication Multiplication by by coordination coordination factor factor based based on on operating operating experience experience

Calculation Calculation of of failure failure risk risk depending depending on on assumed assumed coordination coordination withstand withstand voltage voltage

Coordination Coordination withstand withstand voltage voltage (0% value) Statistical (10% value) Assumed Statistical U Ucw Assumed conventional conventional U Ucw cw (0% value) cw (10% value) Fachgebiet Hochspannungstechnik


- 33 -

Procedure for Insulation Coordination in Four Steps Determination of the required withstand voltages Urw • The required withstand voltages are determined by converting the coordination withstand voltages to appropriate standard test conditions. • Usually different from the coordination withstand voltages. • Derived from the coordination withstand voltages Ucw by the safety factor Ks and the atmospheric correction factor Kt or the altitude correction factor Ka.



- 34 -

Procedure for Insulation Coordination in Four Steps Influences covered by the safety factor Ks • • • • •

Differences in equipment assembly Dispersion in product quality Quality of installation Aging of the installation during expected lifetime Other unknown influences



- 35 -

Procedure for Insulation Coordination in Four Steps Determination of the required withstand voltages Urw • The required withstand voltages are determined by converting the coordination withstand voltages to appropriate standard test conditions. • Usually different from the coordination withstand voltages. • Derived from the coordination withstand voltages Ucw by the safety factor Ks and/or the altitude correction factor Ka.



- 36 -

Procedure for Insulation Coordination in Four Steps Selection of the rated and of the standard insulation level (set of standard rated withstand voltages Uw) • Most economical set of standard withstand voltages Uw of the insulation to prove that all the required withstand voltages are met. • For each range (I or II) a combination of only two withstand voltages defined: Range I: standard lightning impulse withstand voltage standard short-duration power-frequency withstand voltage Range II: standard switching impulse withstand voltage standard lightning impulse withstand voltage • For range I, only phase-to-earth standard withstand voltages are defined, which have to cover phase-to-earth, phase-to-phase and longitudinal insulation.



- 37 -

Procedure for Insulation Coordination in Four Steps Definitions



- 38 -

Procedure for Insulation Coordination in Four Steps Examples for… ... non-self-restoring insulation (power transformers, instrument transformers*)) *) mixed insulation


... self-restoring insulation (disconnectors, insulators)


- 39 -

Procedure for Insulation Coordination in Four Steps List of standard short-duration power-frequency withstand voltages (r.m.s. values in kV)

10

20

28

38

50

70

95

140

185

230

275

325

360

395

460

480

510

570

630

List of standard impulse withstand voltages (peak values in kV)

20

40

60

75

95

125

145

170

250

325

450

550

650

750

850

950

1050 1175

1300 1425 1550 1675 1800 1950 2100 2250 2400 [IEC 60071-1] Fachgebiet Hochspannungstechnik


- 40 -

Procedure for Insulation Coordination in Four Steps Range I: Um = 1 kV up to and including Um = 245 kV The standard voltage values are all the same for • phase-to-earth-, • phase-to-phase-, • longitudinal insulation!



- 41 -

Procedure for Insulation Coordination in Four Steps Range II: Um above 245 kV Different standard voltage values for • phase-to-earth-, • phase-to-phase-, • longitudinal insulation!



- 42 -

Procedure for Insulation Coordination in Four Steps Outcome of insulation coordination – For three types of insulation » phase to ground » phase to phase » longitudinal – and for 4 values each of required withstand voltages Urw » required continuous operating voltage » required short-duration power-frequency withstand voltage » required switching impulse withstand voltage » required lightning impulse withstand voltage

Standardization of tests for equipment – Reduction of these 12 values to a necessary minimum number of withstand voltages Uw of the insulation – Determination of necessary withstand voltages from tables for two ranges of highest voltage for equipment Fachgebiet Hochspannungstechnik


- 43 -

twelve voltages

Procedure for Insulation Coordination in Four Steps - Summary Flow chart acc. to IEC 60071-1 (Figure 1)

[IEC 60071-1]

continued next slide Fachgebiet Hochspannungstechnik


- 44 -

Procedure for Insulation Coordination in Four Steps - Summary Flow chart acc. to IEC 60071-1 (Figure 1) (continued)



- 45 -

Overvoltage Protection and Insulation Coordination

Recommend Documents