IEEE c37.122.2 - 2011

IEEE Guide for the Application of GasInsulated Substations 1 kV to 52 kV

IEEE Power & Energy Society

Sponsored by the Substations Committee

IEEE 3 Park Avenue New York, NY 10016-5997 USA

IEEE Std C37.122.2™-2011

17 February 2012

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IEEE Std C37.122.2™-2011

IEEE Guide for the Application of GasInsulated Substations 1 kV to 52 kV Sponsor

Substations Committee of the

IEEE Power & Energy Society Approved 7 December 2011

IEEE-SA Standards Board

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Abstract: The technical requirements for the design, fabrication, testing, and installation of indoor gas-insulated substations (GIS) 1 kV up to 52 kV are covered. Parameters to be supplied by the purchaser are suggested and technical requirements for the design, fabrication, testing, and installations to be furnished by the manufacturer are established. Keywords: IEEE C37.122.2, gas-insulated substation, GIS, GIS design, GIS equipment, GIS installation, GIS testing, SF 6 , sulfur hexafluoride 

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Introduction This introduction is not part of IEEE Std C37.122.2-2011, IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV.

IEEE Std C37.122TM-1983 IEEE Standard for Gas-Insulated Substations was initiated in the early 1970s when the first gas-insulated substations (GIS) were introduced. Approved in 1983, 1993, and reaffirmed in 2002, it contains standards, recommended practices, and guides. Circumstances beyond the control of the responsible Technical Committees delayed its availability to users until late 1988. Simultaneous to its publication, the Gas-Insulated Substations Subcommittee of the IEEE Power & Energy Society Substations Committee began work on the necessary update and revision of the document. IEEE Std C37.122.1TM Guide for Gas-Insulated Substations was approved in 1993. That guide focused on the technical requirements for the design, fabrication, testing, and installation of a GIS in general 52 kV and above. Parameters to be supplied by the purchaser are suggested and technical requirements for the design, fabrication, testing, and installation to be furnished by the manufacturer is established. During the Working Group and Subcommittee deliberations on the update, it was recognized that users would be better served if the original documents IEEE Std C37.122-1993 (a standard) and IEEE Std C37.122.1-1993 (a guide) were supplemented with a guide for equipment rated 1 kV to 52 kV. The third document became IEEE Std C37.122.2TM-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV. The three documents can be referred to individually or jointly depending on the purpose of the referral. IEEE Std C37.122.2 is also based on GIS of the same voltage range covered by IEC 62271-200.

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Participants Although all Working Groups of the Gas-Insulated Substations Subcommittee contributed to this revision, the prime responsibility belonged to Working Group K3, which proposed this guide. At the time this IEEE guide was completed, the K3 Working Group had the following membership: G. W. Becker, Chair P. Blohm, Vice Chair Arun Arora Peter Blohm Phil Bolin John Brunke

Ted Burse Jack Gustin Richard Jones Heinz-Willi Juelicher Hermann Koch

Shawn Lav Jeffrey Nelson Ted Olsen Arno Wahle

The Gas-Insulated Substations Subcommittee of the IEEE Power & Energy Society that prepared and reviewed this guide had the following membership: A. Arora, Chair H. Koch, Past Chair G. Becker, Vice Chair Markus Etter, Secretary Stephen Arnold Bill Bergman Peter Blohm Lutz Boettger Phil Bolin Hugues Bosia Michel Bues Ted Burse Paul Coventry Rick Crowdis Wolfgang Degen

Gary Engmann Jack Gustin Mel Hopkins Richard Jones Heinz-Willi Juelicher Shin-ichi Kobayashi Eresha Lam Shawn Lav Daniel Lauzon Johny Luiz

Aram Markarians Thomas McNamara Venkatesh Minisandram Mike Muhlenhaupt Jeffrey Nelson Darin Penner Philippe Ponchon Mansour Pourcyrous Arno Wahle Darren Vogt Allen Xi

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The following members of the individual balloting committee voted on this guide. Balloters may have voted for approval, disapproval, or abstention. William J. Ackerman Arun Arora George Becker W. J. Bill Bergman Wallace Binder William Bloethe John H. Brunke Eldridge Byron Arvind K. Chaudhary Randy Clelland Jerry Corkran Robert Damron Gary Donner Michael Dood Dana Dufield Denis Dufournet Edgar Dullni Donald Dunn Douglas Edwards Kenneth Edwards Gary Engmann Markus Etter James Fairris Patrick Fitzgerald Marcel Fortin Mietek Glinkowski

Jalal Gohari Edwin Goodwin James Graham Randall Groves Charles Hand Steven Hensley Lee Herron Gary Heuston Scott Hietpas R. Jackson Wayne Johnson Andrew Jones Laszlo Kadar Tanuj Khandelwal Yuri Khersonsky J. Koepfinger Jim Kulchisky Saumen Kundu Chung-Yiu Lam Hua Liu Albert Livshitz Greg Luri Jorge Marquez William McBride Gary Michel Georges Montillet Dennis Neitzel

Jeffrey Nelson Michael S. Newman T. Olsen Lorraine Padden Christopher Petrola Anthony Picagli Iulian Profir Michael Roberts Anne-Ma Sahazizian Bartien Sayogo Devki Sharma Gil Shultz James Smith Jerry Smith David Solhtalab John Spare Ralph Stell Gary Stoedter John Toth John Vergis Waldemar Von Miller John Webb Kenneth White James Wikston James Wilson Sandeep Zope

When the IEEE-SA Standards Board approved this guide on 7 December 2011, it had the following membership: Richard H. Hulett, Chair John Kulick, Vice Chair Robert M. Grow, Past President Judith Gorman, Secretary Masayuki Ariyoshi William Bartley Ted Burse Clint Chaplin Wael Diab Jean-Philippe Faure Alexander Gelman Paul Houzé

Jim Hughes Joseph L. Koepfinger* David J. Law Thomas Lee Hung Ling Oleg Logvinov Ted Olsen

Gary Robinson Jon Walter Rosdahl Sam Sciacca Mike Seavey Curtis Siller Phil Winston Howard L. Wolfman Don Wright

*Member Emeritus

Also included are the following nonvoting IEEE-SA Standards Board liaisons: Satish Aggarwal, NRC Representative Richard DeBlasio, DOE Representative Michael Janezic, NIST Representative Don Messina IEEE Standards Program Manager, Document Development Erin Spiewak IEEE Standards Program Manager, Document Development

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Contents 1. Overview .................................................................................................................................................... 1 1.1 Scope ................................................................................................................................................... 1 2. Normative references.................................................................................................................................. 1 3. Definitions .................................................................................................................................................. 3 4. Guidelines for GIS equipment 1 kV up to 52 kV ....................................................................................... 4 4.1 Specification ........................................................................................................................................ 4 4.2 Installation, operation, and maintenance ........................................................................................... 19 4.3 Testing procedures............................................................................................................................. 24 4.4 Documentation................................................................................................................................... 26 Annex A (informative) Switching device duty cycles.................................................................................. 27 A.1 Circuit breaker and disconnect switch duty cycles ........................................................................... 27 Annex B (informative) Sequence of operation ............................................................................................. 28 B.1 Sequence of operations for typical applications on feeder circuits ................................................... 28 B.2 Sequence of operations for main bus grounding on sectionalized bus arrangements ....................... 29 Annex C (informative) Bibliography............................................................................................................ 31

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IEEE Guide for the Application of GasInsulated Substations 1 kV to 52 kV IMPORTANT NOTICE: This standard is not intended to ensure safety, security, health, or environmental protection. Implementers of the standard are responsible for determining appropriate safety, security, environmental, and health practices or regulatory requirements. This IEEE document is made available for use subject to important notices and legal disclaimers. These notices and disclaimers appear in all publications containing this document and may be found under the heading “Important Notice” or “Important Notices and Disclaimers Concerning IEEE Documents.” They can also be obtained on request from IEEE or viewed at http://standards.ieee.org/IPR/disclaimers.html.

1. Overview

1.1 Scope This guide provides information regarding the planning, specification, testing, installation, operation, and maintenance of indoor gas-insulated substations (GIS) and equipment.

2. Normative references The following referenced documents are indispensable for the application of this document (i.e., they must be understood and used, so each referenced document is cited in text and its relationship to this document is explained). For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies. ASTM D2472, Standard Specification for Sulfur Hexafluoride. 1 CIGRE 276, Guide for the preparation of customised “Practical SF 6 handling instructions.”

1

ASTM publications are available from the American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, USA (http://www.astm.org/).

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IEEE Std C37.122.2-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV

IEC 60376, Specification and acceptance of new sulfur hexafluoride. 2 IEC 61243-5, Live working—Voltage detectors—Part 5: Voltage detecting systems (VDS). IEC 61634, High-voltage switchgear and controlgear—Use and handling of sulfur hexafluoride in highvoltage switchgear. IEC 62271-1, High-voltage switchgear and controlgear—Part 1: Common specifications. IEC 62271-100, High-voltage switchgear and controlgear—Part 100: High-voltage alternating-current circuit-breakers. IEC 62271-102, High-voltage switchgear and controlgear—Part 102: Alternating current disconnect switches and earthing switches. IEC 62271-200, High-voltage switchgear and controlgear—Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV. IEEE Std 80TM, IEEE Guide for Safety in AC Substation Grounding. 3,

4

IEEE Std 142TM, IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems (Green Book). IEEE Std 344TM, IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations. IEEE Std 693TM, IEEE Recommended Practices for Seismic Design of Substations. IEEE Std C37.04TM, IEEE Standard Rating Structure for AC High-Voltage Circuit Breakers. IEEE Std C37.06TM, IEEE Standard for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis—Preferred Ratings and Related Required Capabilities for Voltage Above 1000 V. IEEE Std C37.09TM, IEEE Standard Test Procedure for AC High-Voltage Circuit Breakers Rated on a Symmetrical Current Basis. IEEE Std C37.98TM, IEEE Standard for Seismic Testing of Relays. IEEE Std C37.122TM, IEEE Standard for Gas-Insulated Substations. IEEE Std C37.122.1TM, IEEE Guide for Gas-Insulated Substations. IEEE Std C37.20.2TM, IEEE Standard for Metalclad Switchgear.

2 IEC publications are available from IEC Sales Department, Case Postale 131, 3 rue de Varembe, CH-1211, Geneva 20, Switzerland/Suisse. IEC publications are also available in the United States from the Sales Department, American National Standards Institute, 11 West 42nd Street, 13th Floor, New York, NY 10036, USA. 3 IEEE publications are available from The Institute of Electrical and Electronics Engineers, 445 Hoes Lane, P.O. Box 1331, Piscataway, NJ 08855-1331, USA. 4 The IEEE standards or products referred to in this clause are trademarks of The Institute of Electrical and Electronics Engineers, Inc.

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IEEE Std C37.122.2-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV

3. Definitions For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary: Glossary of Terms and Definitions 5 should be consulted for terms not defined in this clause. assembly (gas-insulated substation [GIS]): A collection of GIS components that are interconnected and ready for insertion as a subassembly in a GIS, such as a breaker panel shipping assembly. The term is also used to describe a complete GIS. auxiliary circuits: All control, indicating, and measuring circuits. compartment (gas-insulated substation [GIS]): Any gas section of the gas-insulated equipment assembly between the gas barrier insulators. continuous enclosure: A bus enclosure in which the consecutive sections of the enclosure are electrically bonded together to provide a continuous current path through the entire enclosure length. continuous monitoring: The process of sampling the state of some phenomenon at a time interval shorter than the time constant of the phenomenon. design pressure (working pressure): The maximum steady-state gas pressure to which a gas-insulated equipment enclosure is subjected under normal operating conditions. disconnect switch: The term used to identify a switch used to open or isolate a circuit. grounding (earthing): In relation to IEC standards and guides, earthing should be understood as grounding. enclosure currents: Currents that result from the voltages induced in the metallic enclosure by effects of currents flowing in the enclosed conductors. gas barrier insulator: A spacer insulator specifically designed to prevent passage of gas from one gas compartment to another. gas density, minimum: The minimum operating gas density at which the gas-insulated equipment and its components are designed to meet their assigned electrical ratings. gas density, nominal: The manufacturer’s recommended operating gas density (usually expressed as a pressure at 20 °C). gas-insulated substation (switchgear): A compact, multi-component assembly, enclosed in a grounded metallic housing in which the primary insulating medium is a compressed gas, and that normally consists of buses, switchgear, and associated equipment. gas leakage: Loss of insulating gas from the pressurized compartment. main circuit: All the conducting parts of the gas-insulated substation assembly included in or connected to the circuits that its switching devices are designed to close or open. malfunction: The loss of capability to initiate or sustain a required function, often a protective action, or the initiation of undesired spurious action.

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IEEE Standards Dictionary: Glossary of Terms and Definitions is available at http://shop.ieee.org.

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IEEE Std C37.122.2-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV

metallic enclosure: A leak-tight enclosure that contains the compressed insulating gas and associated electrical equipment. moisture content: The amount of water in parts per million by volume (ppmv) that is in the gaseous state and mixed with the insulating gas. periodic inspection: The routine observation of the equipment operating condition. pressure relief device/rupture disk: Device to limit the pressure in a gas-filled compartment. single-phase enclosure: A metallic enclosure containing the buses and/or devices associated with one phase of a multiple-phase system. three-phase enclosure: A metallic enclosure containing the buses and/or devices associated with all three phases of a multiple-phase system. spacer (insulator): An insulator used to support the inner conductor in the enclosure. station ground: A ground grid including a system of grounding electrodes buried beneath or adjacent to the gas-insulated substation that controls the rise of ground voltage level relative to remote earth and controls the distribution of voltage gradients within the gas-insulated substation area during a fault. See IEEE Std 80TM for details. sulfur hexafluoride (SF 6 ): A gaseous dielectric for high-voltage power applications having characteristics as specified in IEC 60376 and ASTM D2472. transition compartment: The compartment specifically designed for joining gas-insulated substation equipment of different design or manufacture. This compartment provides the necessary transition for the current-carrying conductor and the enclosure. type (design) tests: Tests made on representative samples that are intended to be used as part of routine production. The applicable portions of these type tests may also be used to evaluate modifications of a previous design and to ensure that performance has not been adversely affected.

4. Guidelines for GIS equipment 1 kV up to 52 kV

4.1 Specification The specification of the GIS is based upon the single-line diagram, and it will be possible to prepare sketches of different GIS designs and layouts which are available and to see how these may be used in the actual project, including the relation to site and civil requirements. 4.1.1 GIS one-line, specification documentation and service conditions The following is a listing of the necessary documentation that should be included in a GIS specification: 

One-line switching diagram



One-line metering and relaying diagram

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IEEE Std C37.122.2-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV



Site plan



Site conditions (access restrictions, space limitations, ambient temperature, humidity, site altitude, pollution, special environmental conditions)



Building layout and arrangement



Primary equipment (requirements and ratings including instrument transformer requirements)



Secondary equipment (protection and control, metering, interlocking, station service sources ac and dc, etc.)



Engineering system data (star-point grounding method, short circuit duty, etc.)



Maintenance and operation requirements (local safety requirements, interlock schemes)



Project schedule and deliverables



Connections to other equipment (cable, cable bus, solid insulated bus, or gas-insulated bus)

Special attention has to be given to the interfacing between the GIS and other components of the network, such as overhead lines, transformers, cables, etc. The type and the location of these connections will have a major impact on the overall layout and cost. 4.1.2 GIS arrangement and bus schemes The bus schemes illustrated in Figure 1 are those most commonly applied in North America. These commonly applied arrangements are based on typical distribution system designs.

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IEEE Std C37.122.2-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV

Single bus gas-insulated switchgear design

Main and transfer bus gas-insulated switchgear design

Double bus single breaker gas-insulated switchgear design

Figure 1 —Common one-line schemes 6

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IEEE Std C37.122.2-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV

4.1.2.1 Arrangement philosophy and constraints The GIS arrangement is influenced by a number of important constraints including: a)

Bus and bus sections: The arrangement may influence the length of the bus, the orientation of the equipment, and the number of bus sections required.

b)

Position indicators and viewports: The arrangement should afford a clear view of all position indicators for disconnecting and grounding switches. All position indicators should be visible from the floor or a readily accessible platform. Viewports provide direct verification of switch contact (blade) position and should be easily accessible with minimal need to remove hardware, covers, etc.

c)

Expansion: The arrangement should be such that expansion of the original installation can be accomplished with minimum GIS downtime.

d)

Auxiliary connections: The length and the number of terminal points of low-voltage control wiring and SF 6 gas connections should be minimized.

e)

Operation: All operating handles should be accessible and grouped for simplified operation. All indicating devices and gauges should be clearly labeled, visible, and easily accessible.

f)

Configuration: The GIS should be modular and the configuration of the combined components should promote flexibility, a compact design, and simplify retrofit applications.

The GIS equipment arrangements illustrated in Figure 2 are several common arrangements that can be applied. These commonly applied arrangements are based on typical distribution system designs and configurations offered by GIS manufacturers.

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IEEE Std C37.122.2-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV

Figure 2 —Common arrangements

Arrangements are available depending on customer requirements such as disconnect/ground switches located on both sides of circuit breaker positions, VT’s, arresters, etc. Sequence of operation for arrangements without disconnect/ground switches located on both sides of circuit breaker positions are detailed in the Annex B.

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IEEE Std C37.122.2-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV

4.1.3 Engineering studies When the preliminary configuration and the specification data are finalized, further studies may have to be performed. These may cover the following: Engineering studies 

Short circuit studies



Temporary overvoltage (TOV) condition studies



Transient overvoltage study calculations (EMTP)



Capacitor switching studies



Insulation coordination studies



Ferro-resonance studies



Seismic calculations



Civil engineering studies (i.e., floor leveling, foundations, cable basement)



Grounding and bonding studies (grounding calculations for personnel—touch, step, and transfer potentials)



Pressure relief calculations for switchgear room requirements



Seismic studies



Clearance and dimension evaluations



Sound level studies

Logistics studies 

Transport, storage, and erection facilities



Demands imposed by the service and maintenance of the GIS and possible future extensions such as access to equipment and working clearances

4.1.4 Primary equipment data and components A typical GIS procurement specification document includes but is not limited to the following information, not necessarily in the same sequence or with the same title: 

Scope



References



Definitions



Service conditions, (including surface preparation requirements, tool requirements, and spare parts requirements)



Electrical characteristics (including grounding and conduit requiremnts)



Design (including seismic requirements, documentation requirements, layout/clearance dimensions, and sound level requiements)



Operation and interlocking (including training requirements)



Controls



Accessories and appurtenances

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IEEE Std C37.122.2-2011 IEEE Guide for the Application of Gas-Insulated Substations 1 kV to 52 kV



Tests



Drawings, nameplate and instruction manuals



Shipping



Interfaces with existing equipment



Cables



Circuit breakers



Disconnect and ground switches



Motorized operators



Current and voltage transformer location and ratings



CPT’s (control power transformer) location and ratings



Surge arrester locations



Relaying and control cabinet locations

4.1.4.1 Equipment ratings 4.1.4.1.1 Rated maximum voltage and insulation levels The “common values” used in Table 1 apply to phase-to-ground, between phases and across the open switching device. The withstand voltage values “across the isolating distance” are valid only for the switching devices where the clearance between open contacts is designed to meet the safety requirements specified for disconnect switches and grounding switches. Table 1 —Rated maximum voltages and insulation levels (IEEE Std C37.06/C37.22/IEC 62271-1) Rated maximum voltage kV, rms

Rated power-frequency withstand voltage kV, rms Dry 1 min Across the isolating Common value distance

Rated lightning impulse withstand voltage, peak kV Across the isolating Common value distance

IEEE

IEC

IEEE

IEC

IEEE

IEC

IEEE

IEC

IEEE

IEC

4.76 8.25 15.0 15.5 25.8a 25.8 27 38a 38 48.3

7.2 17.5 17.5 24 36 36 36 38 38 52

19 36 36 50 60 60 60 80 80 105

20 38 38 50 70 70 70 70 95 95

20.9 39.6 39.6 55 66 66 66 88 88 115.5

23 45 45 60 80 80 80 77 105 110

60 95 95 110 125 150 125 150 200 250

60 95 95 125 145 170 170 150 200 250

66 104.5 104.5 121 137.5 165 137.5 165 220 275

70 110 110 145 165 195 195 165 220 290

a

These circuit breakers are intended for application on multi-grounded wye distribution circuits equipped with surge arresters.

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4.1.4.1.2 Rated power frequency The rated power frequency is the frequency at which the equipment is designed to operate. The standard frequencies are 50 Hz and 60 Hz. Applications at other frequencies (16 2/3, 25 Hz) should receive special consideration. 4.1.4.1.3 Rated continuous current Table 2 —Rated continuous current (IEEE/IEC) Rated continuous current (amperes, rms) IEEE 600 1200 2000 2500 3000 4000

IEC 630 1250 2000 2500 3150 4000

4.1.4.1.4 Rated short circuit current interrupting capability Table 3 —Rated short circuit current interrupting capability (IEEE/IEC) Circuit breaker rated short circuit current interrupting capability (kA rms) IEEE Std C37.06

IEC 62271-100

16 20 25 31.5 40

16 20 25 31.5 40

4.1.4.1.5 Rated short-time withstand current The standard value of rated short-time withstand current shall be equal to the short circuit current interrupting capability of the switchgear as listed in Table 3. 4.1.4.1.6 Rated duration of short-time withstand current If not explicitly mentioned, the standard value for rated duration of short-time withstand current is 2 seconds based on IEEE standards. 4.1.4.1.7 Rated peak withstand and short-circuit making currents The rated peak withstand and short-circuit making currents shall correspond to the rated frequency. For a rated frequency of 60 Hz it is equal to 2.6 times the rated short-circuit interrupting capability, while for a rated frequency of 50 Hz it is equal to 2.5 times the rated short-circuit interrupting capability.

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4.1.4.1.8 Rated cable charging current Table 4 —Rated cable charging current (IEEE/IEC, Class S1)a Circuit breaker rated cable charging current

a

IEEE Std C37.06

IEC 62271-100

25 A rms at 15 kV 31.5 A rms at 27 kV 50 A rms at 38 kV

25 A rms at 15 kV 31.5 A rms at 25.8 kV 50 A rms at 38 kV

The rated cable charging current, also covers line charging.

4.1.4.1.9 Rated capacitive and inductive current switching capability Table 5 —Rated capacitive current switching capability—isolated capacitor bank (IEEE/IEC, Class S1) Circuit breaker rated capacitive current switching capability Isolated capacitor bank current (amperes, rms) IEEE Std C37.06 250 A rms at 15 kV 160 A rms at 27 kV 100 A rms at 38 kV

IEC 62271-100 400 A rms at 15kV 400 A rms at 25.8 kV 400 A rms at 38 kV

Table 6 —Rated capacitive current switching capability—rated capacitor bank current and back-to-back capacitor bank switching ratings (IEEE/IEC Class S2)a Circuit breaker rated capacitive current switching capability Capacitor bank current back-to-back (amperes) IEEE Std C37.06 IEC 62271-100 630 A rms, 20 kA peak, 4200 Hz at 15.5kV 1000 A rms, 20kA peak, 4200 Hz at 15.5kV 400 A rms, 20 kA peak, 4250 Hz at 15kV 1600 A rms, 20kA peak, 4200 Hz at 15.5kV 630 A rms, 20 kA peak, 4200 Hz at 25.8kV 1000 A rms, 20kA peak, 4200 Hz at 25.8kV 1600 A rms, 20kA peak, 4200 Hz at 25.8kV

400 A rms, 20 kA peak, 4250 Hz at 25.8 kV

630 A rms, 20 kA peak, 4200 Hz at 38 kV 1000 A rms, 20kA peak, 4200 Hz at 38 kV 1600 A rms, 20kA peak, 4200 Hz at 38 kV a

400 A rms, 20 kA peak, 4250 Hz at 38 kV

Inductive switching (i.e., current limiting devices, etc.) should be addressed on a case-by-case basis.

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4.1.4.2 Number of operations Table 7 —Number of operations (IEEE/IEC) Test Number of operations (Operating no-load Cycles (C-O))

Equipment Circuit breaker

Disconnect switch a b

IEEE

IEC

C37.06 15 kV: 5000 or 10 000 27 kV: 2500 38 kV: 1500 C37.22 15kV: 400 27/38 kV: 300

62271-100a Class M1: 2000 Class M2: 10 000 62271-102b Class M0: 1000 Class M1: 2000 Class M2: 10 000

Duty cycles according to IEC 62271-100, definition of M1 and M2 refer to Annex A. Duty cycles according to IEC 62271-102 Addendum A1, 2002, definition of M0, M1, and M2 refer to Annex A.

4.1.4.3 Rated operating sequence The rated operating duty cycle for GIS circuit breakers can be: O-0.3s-CO-3min-CO

(rapid reclosing)

or O-15s-CO-3min-CO

(non-rapid reclosing)

4.1.4.4 Rated pressure of compressed gas system for insulation and/or operation The typical values of rated gauge pressure range from 0.30 bar (4.4 psig) up to 2.20 bar (32 psig) unless otherwise specified by the manufacturer. 4.1.4.5 Primary component detailed descriptions Circuit breakers: In the GIS all breakers are usually vacuum circuit breakers, fixed mounted in an SF 6 gas-insulated compartment. The circuit breakers shall meet the requirements of IEEE C37.06, IEEE C37.09, IEEE C37.04, and IEC 62271-100. For a comparison of the key performance parameters, please refer to Table 3, Table 4, Table 5, Table 6, and Table 7 above. Current transformers: In the GIS both wound and window-type current transformers are available. Voltage transformers: The voltage transformers in the GIS are of the single-phase design and are typically without primary fuses. Primary fuses are available as an option. Control power transformer: Typically control power is provided by a transformer external to the GIS enclosure. 13

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Voltage detectors/indicators: A capacitive device, used to detect voltage presence without the use of a hot-stick, is typically provided. Three-position disconnect switches: A three-position disconnect switch consists of a single-contact system with one drive that has three positions: connected, open, and grounded. This switch is usually a non-load break switch. The threeposition switch is used to isolate the fixed-mounted vacuum circuit breaker and is also used to ground a line or load in combination with the circuit breaker. Terminations: Cable—Plug-in type cable terminations are the standard of the industry to connect power cables to GIS up to 52 kV. Air bushings—Directly mounted air bushings are not typically used in GIS. Bus bar and connections—All bus bar conductors are usually without insulating sleeves, boots, or coverings. Connections between GIS and transformers—These connections can be made through solid insulated bus, gas-insulated bus, bus duct, cable bus, or cable. Surge arresters—Plug-in, dry type surge arresters are commonly used in GIS. 4.1.5 Secondary equipment, control and protection data This subclause outlines in detail the required devices used for the control and protection of the GIS, and details the system interfaces with other components of the associated power system. The following describes the typical secondary equipment for the GIS: 

Protection, control, and interlocking



Monitoring



Supervisory control and data acquisition (SCADA) and communication interface



Wiring connections and interconnection requirements



Annunciation and alarms



Mimic bus diagram

The general requirements and specifications for secondary equipment data for the GIS do not differ substantially from those for conventional metal-clad switchgear and the associated IEEE and IEC standards can therefore be used as a reference. It should also be noted that GIS has disconnect and grounding switches that can be motorized as an option. The additional load of motor-operated switches needs to be considered in designing the station dc system.

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4.1.5.1 Controls Prior to preparing a detailed procurement specification, the user has to make the decision between conventional electro-mechanical controls and microprocessor-based multi-function relays for control, protection, and metering. Microprocessor-based multi-function control units, often called bay control units, offer a number of advantages over conventional controls. These devices greatly simplify the controls design and reduce the amount of secondary wiring by means of internal software logic. Software and hardware are permanently self-supervised. An integrated liquid crystal display (LCD) displays the single-line diagram with active position indications as well as measured signals, alarm annunciation, and other functions. Pushbuttons are available to select switching devices and operate them. All interlocking between the different switching devices of the GIS as well as interlocking with external devices are pre-programmed in the bay control unit. A serial interface for remote communication is standard for these devices and facilitates integration of the GIS into SCADA systems. All presently available types of microprocessor-based multi-function control units can be installed into the local control cabinet which is usually part of each section of the GIS. 4.1.5.2 Relay protection All required protection functions should be shown on a detailed metering and relaying one-line diagram. The user should list all protective functions that are required in a relay list that accompanies the single-line diagram. Common practice is to utilize multi-function microprocessor based protective relays that offer a choice of different protection functions as well as controls. Separate panels for protective relays may be required by the user. 4.1.5.3 Remote control interface It is important to specify the type of remote control and SCADA system that is desired. In the case of hardwired signals to a remote terminal unit (RTU), the user should specify the type and number of control and indication points to be wired. The GIS manufacturer should make sufficient provisions for terminal blocks and transducers. If a serial interface for protective relays or bay control units is utilized for remote control and supervision, it is important to provide detailed specifications for the communication medium and for the communication protocol in addition to the number and type of signals. 4.1.5.4 Interlocking The basic interlocking between disconnect switches, ground switches, and circuit breakers are provided by the manufacturer as a standard. In most cases, these interlocks are either electrical or intrinsic (in the case of three-position switches). If microprocessor-based bay control units are used, the interlocking becomes part of the control logic. The user should specify any additional interlocking requirements such as mechanical/key interlocking in the specification. External interlocking with connected switchgear or other parts of the GIS must be specified.

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4.1.5.5 Control power The control voltage should be specified by the user. Control voltages are typically: 120 Vac, 240 Vac, 48 Vdc, 125 Vdc, 250 Vdc. 4.1.6 Control wiring practices The general control wiring practices for the GIS do not differ substantially from those of conventional metal-clad switchgear. The requirements of IEEE Std C37.20.2 can also be applied to the GIS. The following summarizes those requirements and highlights specific user requirements for the GIS. 4.1.6.1 Control, secondary, and logic-level wiring Flame-retardant, 600 V, 90 °C, insulated stranded tinned copper wire should be used for internal wiring between components of switchgear assemblies and to terminals for connection to external controls, metering, or instrumentation. Wiring within components is assumed to be covered by standards applicable to those devices and is not covered by this guide. Wiring for the purpose of providing power to external GIS loads is not covered by this guide. The GIS manufacturer is responsible for the performance of the wiring system provided by the manufacturer within the switchgear. This applies to the integrity of internally generated signals in the control wiring and may require the use of special precautions such as shielded wire and segregation of certain wires. 4.1.6.2 Wiring across hinges The wiring that crosses a hinge should be sufficiently flexible to withstand repeated door movement without sustaining damage to the wire strands or insulation. The loop formed by the wiring as it crosses the hinge should be covered by a protective wiring harness and secured to the equipment. The wire loop should be protected against damage if the door is removed. No sharp edges or objects should be allowed in the path of the wire loop while the door is operated. 4.1.6.3 Wire sizes Wire sizes should be specified by the manufacturer and shall be designed for the required maximum steady-state loads. The sizes chosen also should accommodate voltage drop within the switchgear, including the effect of intermittent heavy loads (shunt trip and close coils, inrush from relays, etc.). As a minimum, the criteria of IEEE Std C37.20.2, should be met. 4.1.6.4 Wire protection and support Bushings, grommets, or other mechanical protection should be provided for wiring where it passes through a metal sheet, barrier, or raceway. Wiring should be adequately supported to prevent stress from causing damage to the conductors or the insulation.

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4.1.6.5 Terminal blocks Terminal blocks incorporating plug-in or screw terminals should accommodate wire lugs or similar devices affixed to stranded wire. Plug-in or screw type terminals intended for use with stranded wire should be such that all strands of the conductor are confined. Terminal blocks that incorporate pressure connectors should not damage the wire, and when terminating stranded conductors, all strands should be clamped within the connector. Terminal blocks for external control connections and current transformer connections to shorting type terminal blocks should be screw or ring tongue connections, and should be suitable to accept up to a wire size of AWG No. 10 stranded wire. 4.1.7 Grounding The grounding of the GIS equipment shall be in accordance with IEEE Std 80 and IEEE Std 142. 4.1.7.1 General The frame of each enclosure section should be provided with a grounding terminal pad or ground bus bar for connection to a grounding conductor suitable for the specified fault conditions. The short-circuit current ratings applicable to the grounding circuit shall be equal to or greater than the rated short time and rated peak withstand current rating. 4.1.7.2 Grounding of the primary circuit To ensure personnel safety during maintenance work, all parts of the main circuit to which access is required or provided shall be grounded prior to becoming accessible to personnel. This does not apply to removable parts (e.g., plug-in arresters or voltage transformers) which become accessible after being separated from the switchgear. Grounding may be accomplished by a combination of circuit breaker and three-position switch or by the application of worker’s grounds using a “hot stick” and grounding clamps after the circuit has been deenergized and tested for potential. 4.1.7.3 Grounding of the enclosure A ground bus should be included that will electrically connect together the structures in the GIS assembly in or on which primary equipment or devices are mounted. The GIS ground bus shall be connected to the ground grid in two locations or more as required by the manufacturer or by the grounding study. Electromagnetic compatibility (EMC) demands for the installation may require a special approach in the grounding of the switchgear. Factory-built transport units shall be interconnected during final installation through a grounding conductor. This interconnection between the adjacent transport units shall be capable of carrying the rated short-time and peak withstand current for the grounding circuit. If using single-phase enclosed switchgear, bonding connections (i.e., the interconnections between the enclosures of the three phases) should be installed to carry the induced current. Each of these bonding connections should be connected as directly as possible to the general ground grid by a conductor capable of carrying the rated short-time and peak withstand current for the grounding circuit. 17

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4.1.8 Seismic requirements The following sub-sections contain guidelines to ensure functional adequacy of GIS installations under seismic disturbances. General recommendations on seismic design of substations are provided in IEEE Std 693. Further information is also provided in IEEE Std C37.122.1. In addition to this guide and the above-mentioned IEEE Standards and Guides, further detailed and sitespecific information has to be considered by the design engineer and discussed with the manufacturer. 4.1.8.1 Seismic features There are several features that distinguish the behavior of gas-insulated from air-insulated switchgear under seismic influence. a)

The GIS up to 52 kV is for indoor installation only. As a consequence, the building design needs to incorporate the site-specific seismic requirements.

b)

The GIS is characterized by a number of individual gas compartments. Their structural design ensures gas-tightness even under seismic conditions.

c)

The GIS typically improves the withstand capability under seismic stress due to increased compactness.

4.1.8.2 Seismic qualification methods The use of the methods and procedures described in IEEE Std 693 satisfies the requirements of this guide. Alternative methods that can be agreed between the user and the manufacturer include the following (for further description, see IEEE Std C37.122): 

Mathematical modeling



Analytical methods (static or dynamic)



Seismic testing per IEEE Std 693



Simplified seismic verification procedure for low seismic exposure

4.1.8.3 GIS building and foundations As much as practical, it is recommended to place all interconnected equipment on a monolithic foundation to reduce differential movement. If interconnected equipment is not on the same foundation, means to accommodate the expected differential movement should be provided. The building design and layout should follow the applicable building codes and have at least the same seismic withstand capability as the GIS, to prevent damage to the equipment from falling debris or collapse of the building. 4.1.8.4 Floor anchoring The GIS is typically bolted with leveling bolts or anchors to the floor frames or profiles that are embedded into the grouting of the foundation. Anchor systems should be designed to accommodate the tensile, shear, moment, and axial loads and any combination thereof that might be experienced during the design earthquake. Specific anchoring by means of bolting or welding should be considered in locations where

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seismic qualification is required. Tolerances for leveling of the line up should be coordinated with the manufacturer. 4.1.8.5 Interconnections to adjacent equipment Interconnections between items of equipment should accommodate large relative, axial, lateral, moment, and torsional motions as structurally and dynamically dissimilar structures experience large relative displacements under seismic conditions. Leads and interconnections should be designed to allow such displacement without damage. The methods and materials used for interconnections are an important consideration (e.g., cable connections versus bus connections) that should be discussed between the user and the manufacturer. 4.1.9 Monitoring systems 4.1.9.1 Gas pressure and density monitoring The gas pressure or gas density in the GIS is measured with manometers, electronic gas pressure sensors, or gas density monitors. All gas compartments are monitored. Typically one or more auxiliary contacts are provided for remote or local signaling of pressure alarm indication. The low pressure lock-out function typically used for high-voltage SF 6 breakers is not typically applied in this type of GIS, because the interruption performance of the vacuum circuit breakers is not affected by the surrounding SF 6 pressure.

4.2 Installation, operation, and maintenance 4.2.1 Safety The recommendations of this subclause are not intended to replace or invalidate present applicable standards of safety, but rather to augment such standards with respect to the special factors involved in the operation and maintenance of GIS equipment. 4.2.1.1 General The GIS is intended to operate in all cases where the installation and maintenance is carried out in accordance with the manufacturer’s installation and maintenance instructions. The GIS should be operated and maintained by skilled and trained personnel only. 4.2.1.2 Operational safety Due to the gas-tight sealing, foreign solid objects and dust cannot enter the compartments. Depending on the basic design of the switchgear, any moisture penetrating the seals is absorbed by desiccant agents mounted inside the individual compartments. The GIS pressure systems are sealed for the expected operational life of the switchgear and have gas pressure or density monitoring equipment. In the case of gas losses, the switchgear can still be operated since the rated performance is ensured down to the minimum operating pressure as stated by the manufacturer. The pressure alarm is typically set to

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initiate before the lowest permissible pressure is reached. Provision should be made for the alarm(s) to be transmitted to the user’s central control room. The user should consult the manufacturer on the course of action to take as a result of loss of gas pressure. 4.2.1.3 Personnel safety The GIS offers a high level of safety to the operator regarding electric shock with respect to the primary circuit. When viewports are used as a means of switch contact position verification, a sign should be installed near each viewport to warn of possible danger when viewing the interior during switch operation. The suggested wording is as follows: WARNING Do not look into the view port during switch operation. Arcing may damage your eyes. The area around the viewport and/or viewport cover should be painted in a distinctive color for easier identification of viewport locations. 4.2.1.3.1 Personnel safety during normal operation GIS incorporating vacuum circuit breakers does not produce toxic by-products originating out of current quenching arcs. The insulation gas stays stable. If the gas needs to be removed in case of maintenance work, then gas maintenance equipment should be used to minimize environmental effects. 4.2.1.3.2 Personnel safety in the event of faults Gas leakage may occur after a severe electrical or mechanical failure of the enclosure system. In such a case leakages of SF 6 can be expected from the compartments concerned. If heat (fire, arcing) is involved, additional decompositions may be expected as part of the leaking gas. Personnel should not enter rooms in this case. Rooms should only be entered when sufficient forced ventilation is in place. In the event of an internal arc fault, pressure builds up in the enclosure and gas with by-products will be relieved through a rupture disk/pressure relief device into the switchgear room. Hot gasses should be routed away from the operating areas to minimize the risk of injuries. After such an incident, the switchgear room should be ventilated thoroughly before any personnel enter the room. Protective equipment such as masks, gloves, etc. should be used while cleaning the equipment and the switchgear room. Dry, powdery residual substances should be removed, preferably with an industrial vacuum cleaner (filter size 0.3 µm). For more specific information refer to CIGRE 276. 4.2.2 Installation, transport, storage, and equipment handling It is essential that the transport, storage, and installation of the GIS as well as their operation and maintenance in service, be performed in accordance with instructions given by the manufacturer.

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4.2.2.1 Transport, storage, installation, and operation The manufacturer should provide the appropriate instruction manuals for the transport, storage, installation, operation, and maintenance of the GIS. The instructions for the transport and storage should be provided at a convenient time before delivery, and the instructions for the installation, operation, and maintenance should be provided by the time of delivery at the latest. The operation manual may be a separate document from the installation and maintenance manual. The subject GIS is typically shipped partially or completely filled with SF 6 . Details and complete instructions for the installation, operation, and maintenance should be provided by the manufacturer. 4.2.2.2 Conditions during transport, storage, and installation A special agreement should be made between the manufacturer and the user if the service conditions of temperature and humidity defined in the order cannot be guaranteed during transport, storage, and installation. Special precautions may be essential for the protection of insulation during transport, storage, and installation prior to energizing in order to prevent moisture absorption for instance, due to rain, snow, or condensation. Impact recorders or similar devices may be used to monitor impacts or vibrations during transport. Appropriate instructions should be provided. If the switchgear is to be stored for a long period of time, consult with the manufacturer. 4.2.2.3 Installation, unpacking, and lifting For each type of GIS equipment the instructions provided by the manufacturer should include the required information for unpacking and lifting safely, including details of any special lifting and positioning devices which may be necessary. 4.2.2.4 Assembly and installation When the GIS is not fully assembled for transport at the factory, all transport units should be clearly marked. Drawings showing assembly of these parts must be provided with the GIS. Instructions for the installation of the GIS and auxiliary equipment should include sufficient details of locations and foundations to enable site preparation to be completed. These instructions should also indicate the total weight of the apparatus including insulating gas, the weight of SF 6 gas, the weight of the heaviest part of the apparatus to be lifted separately if it exceeds 100 kg (220 lb), and instructions for leveling the switchgear assemblies. 4.2.2.5 Connections Instructions should include information on connections of conductors, connection of auxiliary circuits, connection of grounding, assembly of plug-in connections, and use of cable termination tool kits. 4.2.2.6 Final installation and inspection Instructions should be provided for inspection and tests which should be made after the GIS has been installed and all connections have been completed. These instructions should include a schedule of recommended site tests to establish correct operation, procedures for carrying out any adjustment that may be necessary to obtain correct operation, recommendations for any relevant measurements that should be made and recorded to help with future maintenance decisions, and instructions for final inspection and placing into service.

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4.2.2.7 Basic input data to be provided by the user The following input data should be supplied by the user to ensure ease of installation: a)

Access limitations to the local site

b)

Local working conditions and any restrictions that may apply (e.g., safety equipment, normal working hours, union requirements, etc.)

c)

Availability and capacity of lifting and handling equipment

d)

Availability, number, and experience of local personnel

e)

Interface requirements for connection with other components of the associated power system

In the case of extensions to existing GIS: f)

Provisions for the extensions available within existing primary and secondary equipment

g)

In-service conditions or operating restrictions that must be respected

h)

Safety regulations

4.2.2.8 Basic input data to be provided by the manufacturer The following input data should be supplied by the manufacturer to ensure ease of installation: a)

Space necessary for erection and assembly

b)

Size and weight of components and testing equipment

c)

Site conditions regarding cleanliness and temperature for clean erection and preparation area

d)

Number and experience of local personnel required for erection

e)

Time and activity schedules for erection and commissioning

f)

Electric power, lighting, water, and other needs for erection and commissioning

g)

Proposed training of erection and service personnel

In the case of extension to existing GIS: h)

Out-of-service requirements of existing components related to the erection schedule

i)

Safety precautions

4.2.2.9 Operation The following should be supplied by the manufacturer: a)

A general description of the equipment with particular attention to the technical description of its characteristics and operation so that the user has an adequate understanding of the main principles involved

b)

A description of the safety features of the equipment and the operation of the interlocks and padlocking facilities

c)

A description of the action to be taken to operate the equipment for isolation, grounding, maintenance, and testing

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4.2.3 Gas handling 4.2.3.1 General characteristics of SF 6 SF 6 is a heavy, nontoxic gas consisting of one sulfur atom surrounded by six fluorine atoms. As fluorine is the strongest of oxidizers, the fluorine atoms of SF 6 are tightly bound to the sulfur atom, resulting in a highly stable molecule. As a result of its symmetry, the intermolecular forces between SF 6 molecules are very low, resulting in a very low liquefaction temperature for its relatively high molecular weight. Most materials of similar molecular weight are liquids or solids at room temperature. CAS number:

2551-62-4

Molecular weight:

146.05 g/mol, 5.15 oz/mol

Density:

6.07 kg/m³ at 20 °C and 100 kPa, 0.379 pound/foot³ at 68 °F and 14.5 PSI

Voltage withstand:

8.8 kV/cm bar (air: 3.3 kV/cm bar) , 22.35 kV/inch PSI (air: 8.38 kV/inch PSI) in homogeneous field. Highly electronegative.

For detailed information of physical characteristics see ASTM D2472. 4.2.3.2 Purchasing SF 6 is supplied highly compressed as a liquid in containers. New gas shall meet the requirements of ASTM D2472 or IEC 60376. Any consignment should be accompanied by a certificate of compliance or Material Safety Data Sheet (MSDS). 4.2.3.3 Storage Containers should be handled with care and stored in dry cool places not exposed to the sun and away from any flammable or explosive material. Containers should be stored with their outlet valves directed upwards and well secured. The containers should be clearly labeled as to identify their contents. 4.2.3.4 Filling of switchgear Personnel should be familiar with the properties of SF 6 and should strictly follow the instructions of the manufacturer of the GIS for filling and/or evacuation. 4.2.4 Site work Foundations should be capable of carrying the load of the GIS with suitable excess margin as well as the desired rolling load. Further, the foundations should meet the relevant seismic codes. Further requirements with regard to leveling, surface, etc. shall be in accordance with the manufacturer’s instruction manuals. The connection between the ground bus of the GIS and the ground grid of the substation should have at least the same current withstand as the ground bus of the GIS. Preferably the ground connection to the ground grid should be made on either end of the GIS. The grounding of the GIS equipment should be in accordance with IEEE Std 80. 23

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4.2.5 Inspection, maintenance, and repair Instructions and recommendations of the manufacturer should be strictly followed. The user should perform inspections as per the GIS instruction manual. The maintenance and repair of the GIS should be coordinated with the manufacturer unless specified in the instruction manual.

4.3 Testing procedures 4.3.1 Design tests Design tests are used to prove the design characteristics of GIS and its associated devices and should include the following as per IEEE Std C37.09 and IEC 62271-200: 

Dielectric tests (including power frequency and impulse testing)



Measurement of the resistance of circuits



Temperature rise test



Short time withstand current and peak withstand current test



Verification of the degree of protection (IP coding, mechanical impact)



Tightness test



Electromagnetic compatibility test (EMC)



Mechanical operation test (switching devices, additional tests for disconnect switches, removable parts, interlocks)



Internal arc test

Additional tests for circuit breakers: 

Mechanical endurance tests



Making and breaking tests



Single-phase or double-earth fault tests



Cable charging switching tests



Standard duty cycle tests



Interrupting time tests



Transient recovery voltage (TRV) tests



Capacitor switching current tests



Out-of-phase switching current tests

4.3.2 Production tests Production tests are a suitable means in order to verify the guaranteed quality and the expected product properties of the GIS. These tests usually take place at the manufacturer’s premises covering the final product. Individual components, sub-supplied by others, (e.g., current transformers, voltage transformers, surge arresters, drives, etc.) are commonly tested to the required extent at the sub-supplier’s premises.

24

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The following is a list of routine production tests according to IEC and IEEE Standards: 

Mechanical operation tests—circuit breaker



Measurement of the resistance of the main circuit



SF 6 gas-tightness test



Power frequency voltage withstand test



Partial discharge test



Mechanical operation tests: circuit breakers, disconnect switches and grounding switches



Design and visual checks



Test of auxiliary electrical devices



Voltage withstand test on auxiliary and control circuits



Test on the capacitive voltage indicating system



Verification of correct wiring



Test of voltage and current transformers



Function test of interlocks



Visual inspection



Pressure tests of gas-filled compartments higher than 0.5 bar gauge pressure



Point-to-point wiring check



Nameplate check



Clearance and mechanical adjustment checks



Circuit breaker timing



Operating mechanism mechanical checks



Circuit breaker operating mechanism stored energy system tests

4.3.3 Commissioning tests The following recommended tests and inspections are to be performed on the complete GIS at the site after installation: 

Inspection of impact recorders or similar devices provided by the manufacturer, preferrably after arrival of the GIS at site



General assembly inspection



Gas leakage test



SF 6 moisture and air content test, at least for parts of the GIS that had to be filled at site



Equipment list check



Nameplate check



Component device check



Point-to-point wiring check for wiring connections done on site

25

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

Control system functional test



Voltage test on main circuit with 80% of the power-frequency voltage test values as per Table 1



Voltage test on control wiring for wiring connections done on site



Overall appearance inspection



Current transformer primary or secondary current injection, polarity verifications, ratio tests, saturation tests, insulation tests, and secondary winding resistance measurements



Voltage transformer ratio tests



Verify phasing: primary and secondary



Electrical and mechanical interlocking



Circuit breaker contact resistance test



Circuit breaker timing tests



Circuit breaker mechanical operation tests



Disconnect switch and ground switch operation tests

A certified test and inspection report should be provided for each GIS section and for the entire assembly.

4.4 Documentation The manufacturer should submit a complete drawing and documentation package to the user for review and approval prior to manufacturing. This drawing submittal typically includes the following: 

Physical outline drawings



Floor plan view of the complete GIS



Section views of the typical GIS bays



One-line relaying and metering diagram



AC three-line relaying and metering diagram



Interlocking logic diagram



Wiring connection diagram with opposite end designations



Control schematics



Gas schematic diagram



Control device designations



Instruction/operation/maintenance manuals



Foundation and building design parameters to be provided by the manufacturer



Training materials agreed upon between user and manufacturer

Sequence of operation

26

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Annex A (informative) Switching device duty cycles

A.1 Circuit breaker and disconnect switch duty cycles A.1.1 Duty cycles according to IEC 62271-100, definition of M1 and M2 Circuit-breaker class M1 Circuit-breaker with normal mechanical endurance (mechanically type tested for 2000 operating cycles) Circuit-breaker class M2 Frequently operated circuit-breaker for special service requirements and designed so as to require only limited maintenance as demonstrated by specific type tests (circuit-breaker with extended mechanical endurance, mechanically type tested for 10 000 operating cycles) A.1.2 Duty cycles according to IEC 62271-102, definition of M0, M1, and M2 Disconnect switch class M0 Disconnect switch having a mechanical endurance of 1000 operating cycles, suitable for applications in distribution and transmission systems fulfilling the general requirements of this standard Disconnect switch class M1 Disconnect switch having an extended mechanical endurance of 2000 operating cycles, mainly for applications where the disconnect switch is operated in conjunction with a circuit-breaker of an equal class Disconnect switch class M2 Disconnect switch having an extended mechanical endurance of 10 000 operating cycles, mainly for applications where the disconnect switch is operated in conjunction with a circuit-breaker of an equal class

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Annex B (informative) Sequence of operation

B.1 Sequence of operations for typical applications on feeder circuits It is assumed that a feeder is in the energized condition and the operating sequences described below are of a general nature for GIS. In all cases applicable safety and specific operating rules shall be observed. Sequence of operation for isolation of a feeder: a)

The feeder circuit breaker is switched to the open position [see Figure B.1(a)]. This unlocks the disconnect switch.

b)

The feeder disconnect switch is switched to the open position [see Figure B.1(b)]. Verify by viewing.

c)

The feeder is now isolated on bus side.

a

b

c

d

Figure B.1—Feeder circuits grounding

Sequence of operation for feeder grounding: 1)

Verify circuit is deenergized by means of the integrated voltage detector/indicator.

2)

The grounding switch is switched to closed position [see Figure B.1(c)]. Verify by viewing.

3)

Close the feeder circuit breaker [see Figure B.1(d)].

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4)

Lock feeder circuit breaker in closed position according to manufacturer’s O&M manual.

5)

The feeder is now grounded through the circuit breaker on the line side.

B.2 Sequence of operations for main bus grounding on sectionalized bus arrangements (It is assumed that the tie circuit breaker is in the energized condition.) Sequence of operation for grounding of main bus section A: a)

Open all disconnect switches on “A” bus and verify by viewing.

b)

Block closing of disconnect switches.

c)

Open tie circuit breaker [see Figure B.2(a)].

d)

Open bus “B” disconnect switch of bus tie circuit breaker [see Figure B.2(b)]. Verify by viewing.

e)

Close the bus “B” grounding switch [see Figure B.2(b)] (possible only if all disconnect switches on “A” bus feeders are in open position). Verify by viewing.

f)

Close the tie circuit breaker.

g)

Lock tie circuit breaker in closed position according to manufacturer’s O&M manual.

h)

The “A” bus is now grounded.

A Bus

B Bus

52

a

b

Figure B.2—“A” bus grounded through tie circuit breaker

Sequence of operation for grounding of main bus section B: number sequences 1)

Open all disconnect switches on “B” bus. Verify this by viewing.

2)

Block closing of disconnect switches.

3)

Open the tie circuit breaker.

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4)

Open bus “A” disconnect switch of the bus tie circuit breaker [see Figure B.2(a)]. Verify by viewing.

5)

Close the bus “A” grounding switch [see Figure B.2(a)] (possible only if all disconnect switches on “B” bus feeders are in open position). Verify by viewing.

6)

Close the tie circuit breaker.

7)

Lock tie circuit breaker in closed position according to manufacturer’s O&M manual.

8)

The “B” bus is now grounded.

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Annex C (informative) Bibliography Bibliographical references are resources that provide additional or helpful material but do not need to be understood or used to implement this standard. Reference to these resources is made for informational use only. [B1] IEEE Std 1125TM, IEEE Guide for Moisture Measurement and Control in SF 6 Gas-Insulated Equipment. 6 [B2] IEEE Std C37.122.3TM, IEEE Guide for Sulfur Hexafloride (SF 6 ) Gas Handling for High-Voltage (over 1000 Vac) Equipment. [B3] IEEE Standards Dictionary: Glossary of Terms and Definitions. 7

6

IEEE publications are available from The Institute of Electrical and Electronics Engineers, 445 Hoes Lane, Piscataway, NJ 08854, USA (http://standards.ieee.org/). 7 IEEE Standards Dictionary: Glossary of Terms and Definitions is available at http://shop.ieee.org.

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