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About this book

This handbook offers the whole knowledge of high voltage substations from their design and construction to the maintenance and the ongoing management, the entire asset life-cycle. The content of the book covers a range of substation topologies: Air-Insulated, Gas-Insulated and Mixed Technology Switchgear Substations together with the essential secondary systems. Additionally specialized substations such as ultra high voltage (UHV), offshore substations for wind power plants and the use of gas insulated lines are included.

The book includes topics, providing information for increased reliability and availability, asset management, environmental management aspects, and the adoption of appropriate technological advances in equipment and systems in substations.

The book was written by more than 30 experts from around the world and assembled through the Cigré study committee on Substations. This guarantees that the book contains information that is based on the global exchange and dissemination of unbiased information for technical and non-technical audiences.

Although there are other works containing references to Substations, this book is designed to provide a complete overview of the topic in one book, providing a valuable reference for anyone interested in the topic.

Table of Contents


1. Introduction

CIGRE is the only organization worldwide which for almost 100 years, since 1921, has dedicated its activities to the work of the electricity supply industry. During this time the Substations Study Committee has addressed many and varied topics associated with all aspects of high voltage substations, and this work has been published in the form of Technical Brochures, Electra Papers, Session Papers, and Symposium and Colloquium Papers, and the majority of these are available freely to CIGRE members through the e-CIGRE website. However, these papers usually address specific topics which were particularly relevant or “hot topics” at the time they were written. This means that if one wishes to consider all aspects of high voltage substations, it is not easy to find your way around this mass of information. The purpose of this book is to draw on this wealth of information and to present it in a more accessible and comprehensive way in order to provide a reference book on all aspects of high voltage substations which would be of value to all decision-makers working in this field of expertise. It is hoped that this book will become a standard reference work, present on the bookshelves of all such colleagues.

John Finn, Adriaan Zomers

Planning and Concepts


2. Introduction to Substation Planning and Concepts

The transmission and distribution network performs three main functions:a)The transmission of electric power from generating stations (or other networks) to load centersb)The interconnection function, which improves security of supply and allows a reduction in generation costsc)The supply function, which consists of supplying the electric power to subtransmission or distribution transformers and in some cases to customers directly, connected to the transmission and distribution network

John Finn

3. Type of Switchgear to Be Used

Another important decision made at the planning/concept stage is the type of equipment that will be used for the substation. Three types of equipment are available for selection by a substation designer in order to implement the most appropriate solution for a particular substation, i.e.:Air-insulated switchgear (AIS)Gas-insulated switchgear (GIS)Mixed-technology switchgear (MTS)

Colm Twomey

4. Selecting Circuit Arrangements: Requirements and Reliability

The basic function of circuit arrangements is to facilitate the operational functions of substations inside electrical networks. In the past, maintainability and accessibility of high voltage equipment were very important due to the requirements for frequent maintenance. Different kinds of circuit breaker designs such as oil-filled breakers and air-blast breakers and also the different types of operating mechanisms required regular maintenance in short intervals. These requirements meant that various configurations and arrangements of substations were developed to isolate the circuit breaker and current transformer in a bay for maintenance while ensuring availability of supply on adjacent equipment. Disconnectors are required to deal with safety requirements and provide physical isolation during maintenance activities.

Gerd Lingner

5. Effect of Safety Regulations and Safe Working Practices on Substation Design

From the very beginning of the use of electrical power, it has been known that substations present a significant risk to personnel particularly from electric shock. Consequently, the design of electrical substations has always had to take into account the relevant measures to protect people who may be building, commissioning, operating, maintaining, or decommissioning the substation from these and other risks. In this section the basic logic behind the measures to be adopted is presented, and these will be illustrated in many cases by dimensions. Any dimensions presented in this chapter should be considered as minima, and any designer should be aware that utilities throughout the world have usually developed specific requirements for their own substations. These specific requirements that may be incorporated into safety rules or in some cases legal requirements must be complied with when designing substations for a particular utility.

John Finn

6. Incorporating New Functionalities Into the Substation

Substation design aims to provide a cost-effective solution, which as far as reasonably practicable demonstrates high availability, reliability, and operational flexibility. From the utility perspective, this requirement applies to both brand new as well as 30-year-old substations.

John Finn

7. Substation Specification and Evaluation

In order for the utility or asset owner to obtain the substation that they require, it is necessary for them to clearly specify their requirements. This is usually done by producing a conventional specification in conjunction with a set of commercial terms and conditions.

John Finn

8. Type of Contract for Substations (In House or Turnkey)

Traditionally utilities have had a very high level of technical expertise particularly related to their own systems, substations, and the need for any special requirements for equipment. To ensure that these needs are met fully, the traditional way of contracting was for the project to be managed “in-house” and the design, procurement, installation, and commissioning of substations to be carried out by the utilities’ own staff.

John Finn

9. Innovation and Standardization of Substation Equipment

In recent years, there has been a significant move to introduce innovation into substation equipment. This has been largely driven by manufacturers and solution providers in response to technical developments and commercial pressures. New innovative products have been introduced to the utilities, which can offer many benefits such as reduction of maintenance cost, ease of operation, and simplifying the substation design. In order to really benefit from these innovative products, the utilities may be required to revise their design philosophy and application standards.

Colm Twomey

Air-Insulated Substations


10. Introduction to Air-Insulated Substations

An air-insulated substation (AIS) is one where the main circuit potential is insulated from the ground by air using porcelain or composite insulators and/or bushings. AIS is fully composed from air-insulated technology components such as circuit breakers, disconnecting switches (disconnectors), surge arrestors, instrument transformers, power transformers, capacitors, bus bars, and so on, and the components are connected to each other by stranded flexible conductors, tubes, or buried power cables. AIS is the most common type of substation, accounting for more than 70% of substations all over the world.

Koji Kawakita

11. Basic Design and Analysis of Air-Insulated Substations

Following the conceptual design process described above in Chap. 10, the basic design process determines the detailed designs required to implement the conceptual design decisions. These detailed designs are determined in accordance with international or local standards, laws, rules, and recommendations.

Colm Twomey, Hugh Cunningham, Fabio Nepomuceno Fraga, Antonio Varejão de Godoy, Koji Kawakita

12. Specification and Selection of Main Components for Air-Insulated Substations

There are many elements to be considered when specifying equipment for air-insulated substations. This chapter takes individual items of equipment and describes the requirements that will need to be considered when specifying the correct parameters for the particular installation.

John Nixon, Gerd Lingner, Eugene Bergin

13. Construction of Air-Insulated Substations

After selection of materials and equipment, the next step is to physically construct the substation. The construction process is the process of using the engineering drawings and specified material and equipment to physically construct a new substation or add to an existing substation as required.

Akira Okada

14. Instruction Manuals and Training for Air-Insulated Substations

Manuals and documentation are an important part of substation design standards. IEEE, IEC, and CIGRE brochures are uniquely referenced by manuals as each electric utility or asset owner drafts manuals based on experience and lessons learned. Instruction manuals include many of the chapters contained in this book. An example of standard design topics may include the following:General location and detail of symbols used for drawingsSubstation designs, current utility design practiceSubstation one lines and drawing standardsBus bar schemeFault current levels and calculation of mechanical forcesNeutral point earthing or grounding standardsElectrical equipment design standards and operation instructions and ratingsSwitching guidelines and operator instructions for loop splitting and line droppingControl design standards and general practiceSystem protection and relay standards and general practiceLV AC/DC calculationElectrical equipment standards and ratingsEquipment loading guidelinesPreliminary engineering and estimating guidePermitting and regulatory guidelinesEnvironmental procedures, process, and regulatory requirements for design and constructionUtility safety manualFoundation drawingArchitectural, civil drawings, and calculationsEarthing drawings and calculationsPower cable layoutInsulation coordination study documentAssembly drawings for steelwork

Mark McVey

Gas-Insulated Substations


15. Why Choose GIS?

The main advantage of gas-insulated switchgear (GIS) over AIS or MTS is its compactness which has a direct influence on land requirement, land cost, visual impact, and possible technical applications. The compact size offers high variety in design which in turn allows indoor, outdoor, underground, hybrid, and containerized installations (even for temporary operation). A modular design of GIS in connection with its compactness allows specific site requirements to be met to an extent higher than it is possible for AIS.

Peter Glaubitz, Carolin Siebert, Klaus Zuber

16. GIS Configuration

System-design considerations dictate the requirements for the substation basic configuration as well as its location within the system. Consequently, they also include the basic selection between GIS and AIS. After making the decision for an SF6 gas-insulated system, it is necessary to consider GIS design as described in the following sections.

Peter Glaubitz, Carolin Siebert, Klaus Zuber

17. Insulation Coordination

The coordination of the insulation within GIS depends upon the overvoltages generated in the associated system and the GIS itself. These may consist of:External overvoltageLightning overvoltagesSwitching overvoltagesTemporary overvoltagesAC overvoltages generated by circuit resonance conditionsSpecific for GISDC stressingDC plus AC stressingVery-fast-front overvoltages

Peter Glaubitz, Carolin Siebert, Klaus Zuber

18. GIS Primary Components

The design of conductors, connections, and supports should ensure that thermal and mechanical interaction due to normal currents or short-circuit currents do not worsen the current conduction and dielectric performance of the GIS. Basic criteria and suitable tests are specified in the relevant international standards.

Peter Glaubitz, Carolin Siebert, Klaus Zuber

19. GIS Secondary Equipment

The definition of secondary equipment generally covers all individual components which form part of the switchgear protection, control, and monitoring systems.

Peter Glaubitz, Carolin Siebert, Klaus Zuber

20. Interfaces: Civil Works, Building, Structures, Cables, OHL, Transformers, and Reactors

Prior to commissioning and formal acceptance, the users’ appropriate personnel should be trained by the manufacturer in the operation and maintenance of the GIS equipment.

Peter Glaubitz, Carolin Siebert, Klaus Zuber

21. GIS Earthing

While the physical characteristics of the GIS will have a profound effect on a number of aspects of the design, the basic requirements of an earthing system for a GIS installation are not different to those for an air insulated site, i.e., to protect operating staff against any hazard and to protect equipment against electromagnetic interference and damage.

Peter Glaubitz, Carolin Siebert, Klaus Zuber

22. GIS Testing

International standards specify requirements and define ratings and tests for gas-insulated metal­enclosed switchgear and its individual components. The applicable IEC standards are those defined in the table in Sect. 25.9. (Many of these standards are under revision. The reader is encouraged to use the most recent editions):

Peter Glaubitz, Carolin Siebert, Klaus Zuber

23. SF6, Its Handling Procedures and Regulations

SF6 and its handling are subject to a number of publications, especially from CIGRÉ. However, the most familiar ones for GIS project execution are the IEC standards IEC 60376 (2005–06) (for new gas), IEC 60480 (2004–10) (for used gas), and IEC 62271-4 (2013–08) (for handling of SF6 in high-voltage switchgear).

Peter Glaubitz, Carolin Siebert, Klaus Zuber

24. Training, Service, and Maintenance of Gas-Insulated Substations

Prior to commissioning and formal acceptance, the user’s appropriate personnel should be trained by the manufacturers in the operation and maintenance of the GIS equipment.

Peter Glaubitz, Carolin Siebert, Klaus Zuber

25. Execution of a GIS Substation Project

The initiation of a project is the identification of the need for one or more new switching functions in a network. To satisfy an increased need for more power, for general or industrial supply, or for system availability in a certain area, there will be a need for more power generation and/or a higher transformer capacity. In both cases the solution will include a need for new switching functions, either in the form of a new switchgear for a power plant, a new substation, or an extension of old switchgear which may be of AIS or GIS type.

Peter Glaubitz, Carolin Siebert, Klaus Zuber

Mixed Technology Switchgear Substations and Gas Insulated Lines


26. Mixed Technology Switchgear (MTS) Substations

Gas-insulated switchgear (GIS) and air-insulated switchgear (AIS) use proven technologies to provide safe and reliable power to the public.

Tokio Yamagiwa, Colm Twomey

27. Gas Insulated Lines (GIL)

GIL is a transmission system that can be used as an alternative to conventional cables when overhead lines are not a practical solution. It can be used for complete transmission circuits instead of overhead lines, but in this book we are mainly interested in its use as directly applicable to the substation environment.

Hermann Koch

UHV and Offshore Substations


28. UHV Substations

Ultrahigh-voltage (UHV) and offshore substations are fast-becoming mature applications, but there is a big difference between substation technologies. UHV technology has a relatively long history, and offshore substation technology meets the necessity of recent sustainable electricity supply and the application of the cutting-edge substations. In this part, UHV substations are described in Chap. 28 and offshore substations are described in Chap. 29.

Kyoichi Uehara

29. AC Offshore Substations Associated with Wind Power Plants

It is recognized that there is a global dependence on the finite energy resource of fossil fuel and that alternative and sustainable sources of electrical generation are required. Present developments show a growing interest in renewable and clean energy sources. Rising temperatures, rising sea level, and increasing occurrence of extreme weather conditions have led people to believe we need to change our ways.

John Finn, Peter Sandeberg

Secondary Systems


30. Secondary Systems: Introduction and Scope

So far in this book we have concentrated on the primary plant which makes up a substation, whether it be air insulated, gas insulated, or mixed technology. However, without the secondary systems, the substation would simply be a store house of primary equipment. The secondary systems are the essential ingredients to protect, operate, and control the primary plant and the whole power system, which bring the substation to life.

John Finn, Adriaan Zomers

31. Substation Auxiliary Systems

Substation secondary equipment provides the interface to facilitate functional control, protection, and supervision of the primary plant and indeed the overall power system network. The auxiliary power supplies are sourced from the AC network and distributed as required:To AC loads over the substation low-voltage AC networkFollowing rectification, to DC loads over the DC network

Mick Mackey

32. Substation Protection

The role of protection is not to prevent a fault from occurring but deal with it if one occurs and protect the power network as well as the primary equipment. Protection should detect and isolate the faulty equipment as quickly as possible in order to:Minimize the risk of instability in the system including generatorsMinimize damage to the faulty item of equipmentMinimize risk of damage to adjacent healthy equipment

Richard Adams

33. Substation Control and Automatic Switching

In order to operate the substation effectively, a control system which indicates the status of all plant including alarms and indications of secondary system equipment; shows analogue values for the key parameters such as voltage, current, megawatts, and megavars; as well as provides digital outputs to close and open switchgear, raise and lower taps on transformers, etc. is required. In addition to the basic indications and controls, other functions such as synchronizing, voltage and/or reactive control, interlocking for both safety and operational reasons, load control to avoid frequency collapse, etc. may also be applied. Other functions such as automatic closing or reclosing to optimize the performance of the network may be needed, and in some instances controlled switching, i.e., point on wave control of closing or opening, may be used to reduce switching transients on the network. These aspects will be covered in the following paragraphs.

John Finn

34. Metering and Monitoring

In order to efficiently operate the substation, it is important to know the values of certain key parameters such as the voltage on the bus bars and the current in the circuits together with the values of real and reactive power flowing. Furthermore, it is necessary to know accurately the value of energy transmitted between one utility and another at the point of sale. When faults occur, then establishing the location of the fault may be needed. Additionally, analogue traces of currents and voltages linked to an accurate sequence of events can be very useful in analyzing the cause of the fault. In order to know that all of the equipment is operating correctly and not in need of maintenance, then supervision of the equipment together with suitable monitoring systems may be required. This section deals with these aspects.

John Finn

35. Substation Communications

In recent years, the subject of communications, both within the substation and external to it namely between substations and between the substation and the control center, has become more and more important. The subject is so vast and changing so rapidly that in this book only a very brief introduction to the subject can be given to try to give the reader a basic understanding.

John Finn

36. Substation Digital Equipment

The majority of protection devices used in substations today are digital or numeric devices. Unlike older electromechanical devices that tended to only have one function, digital devices may have many functions, being able to perform several types of protection from the one device, including control functions, fault recording, and condition monitoring. Another benefit of these devices is that they can provide self-supervision and indication of failure should one occur, whereas many old electromechanical devices were unable to provide such indication and any failure would only be detected during maintenance or maloperation/non-operation during an actual fault. Digital devices tend to be smaller than their traditional counterparts, and their use means that fewer discrete relays are required, and hence less panel space, so the number of panels now required for a particular type of circuit is reduced. This mean that relay rooms may in turn be smaller, with consequential reductions in land and civil costs.

Richard Adams

37. Equipment Considerations and Interfaces for Substations

As mentioned in the introduction to this part, the secondary equipment allows the substation to perform its intended functions. This section deals with the main interfaces between the secondary and primary equipment and also the interfaces with the buildings and the earthing system to ensure that the secondary equipment can perform satisfactorily.

John Finn

38. Asset Management of Secondary Systems of Substations

The successful asset management of substation’s secondary systems requires consideration of all aspects over the lifetime of the asset. This includes both technical and economic requirements.

Mick Mackey

Environmental Impact of and on Substations


39. Introduction to the Environmental Impact of and on Substations

The environment is a key consideration in the design and lifetime management of substations. The environment affects the substation and the substation the environment. The effects can be in both cases immediate or develop in time. In case of the environment effects, it is usually a question about how the substation or its equipment will work under the environment in question. Examples of these kinds of effects of the environment on the substation and on substation equipment are such daily phenomena as ambient conditions to which temperature, solar radiation, wind, rain, snow, and accumulation of pollution on insulator surfaces belong. On the other hand, some of the environmental effects can occur much more sporadically but be very severe and cause significant damage and/or disruption. Examples of these are hurricanes, floods, wildfires, earthquakes, and volcanic eruptions. Already the given examples reveal that the effects can be very site specific and vary a lot from one site to the next within a country or within the substations belonging to a single grid owner/operator. We have learned to know best the effects of the environment on substations and their equipment in case of outdoor conditions. Consequently, an essential part of the design guides and different (technical) equipment specifications deals with the question of how the environment has to be taken into account already in the design phase of the substation and equipment selection. In indoor substations, the variation range of environmental factors is usually smaller than those for otherwise equivalent outdoor substations.

Jarmo Elovaara

40. Impact of Ambient Conditions on Substations

External insulation of equipment installed outdoors is directly affected by the external ambient conditions. Installing devices indoors reduces the number of the ambient factors affecting the equipment but does not remove them completely, because indoor installation does not necessarily mean that the system is hermetically sealed and fully protected from all the effects of variation of ambient conditions.

Jarmo Elovaara, Angela Klepac

41. Electromagnetic Interference (EMI) in Substations

The substation has always been a hostile environment for the telecommunication and control/automation systems. With the developing technology, the situation has transformed toward a more difficult one as the use of modern electronic systems and the number of computerized equipment with online automation and increased information transfer capability have strongly increased in protection, supervision, and control/automation equipment. At the same time, the level of energy that the components can survive has decreased, and the extent of the HV systems and the use of even higher operation voltages than before have increased such that the inherent susceptibility of modern automation and telecommunication systems to electromagnetic interference has also increased. New technologies such as fiber optics and decentralized electronics (including integrated electronic sensors/systems) have not been able to remove the interference problems.

Jarmo Elovaara

42. Impact of the Substation on the Environment

So far CIGRE has published very few documents about the impacts of the substations on the environment. In the following paragraphs, these aspects and effects are briefly described. The Technical Brochures of CIGRE are referred to when such have been available.

Jarmo Elovaara

43. Special Risks Related to Substation Equipment (Transformers, Reactors, and Capacitor Banks)

All equipment containing some kind of oil presents a certain risk to the environment. The use of oils in groundwater areas was already considered earlier. Here we concentrate on other aspects of the use of oils.

Jarmo Elovaara

44. Use of SF6 and CF4

The design and use of equipment and installations applying SF6 gas or SF6/CF4 gas mixtures have been considered in Sect. 12.2 and Part C of this handbook. Here emphasis is given to the environmental effects of SF6 gas and mixtures. Also, a review is given on the possibilities to find an alternative gas for SF6 in electrotechnical applications.

Jarmo Elovaara

45. Handling, Recycling, Disposal, and Reuse of Substations

This item has probably not been a subject within any Study Committee or Working Group of CIGRE. Consequently, no Technical Brochures or other publications have been published. However, within corporate members of CIGRE, some new thinking has been gaining ground in this area.

Jarmo Elovaara

Substation Management Issues


46. Asset Management in an Electric Infrastructure

Whole life management, and in particular the cost analysis of substations, is at the core of asset management. Here effective life cycle costing can influence the middle- and long-term investment strategy of power utilities.

Alan Wilson, Mark Osborne, Johan Smit

47. Developing Strategic Policies

Many utilities throughout the world have adopted a business model that aligns and links corporate policies and strategies throughout the organization all the way down to activities undertaken at site. Examples of such statements are listed below. These aims are worthy, and most utilities in the last decade would claim to have adopted similar approaches.Safety performance is a company critical value. Many identify and proclaim that safety concerns are their most important value. This relates to all on-site, staff, contractors, visitors, as well as the public who are neighbors.Finance. Clearly the company must have a sound financial performance, achieving objectives set by owners and regulators. It also means investing in the infrastructure to an adequate level to achieve the agreed performance level.Quality of service and reliability. This involves not only reliability of the assets and the network but also loss of supply events. The latter are usually reportable events monitored by the regulator who may reward or penalize performance.Environmental impact. Companies will promote their care for the environment and be careful to manage any oil spills, excessive noise, and release of greenhouse gases or polluting fires after an equipment failure.

Paul Leemans, Mark Osborne, Johan Smit

48. Whole Life Management of Substations

This chapter provides some guidance on the factors that need to be considered when deciding the policy to be adopted as the plant matures and the tools and techniques which can be used to assess the condition of the equipment.

Nhora Barrera, Mark Osborne, Johan Smit

49. Commissioning

This chapter is not intended to be a manual on how to commission a substation, new bay, or refurbished bay but to explain the basic principles and processes of the commissioning activity. Some people query whether commissioning is the last part of the installation process or is it the first part of the management process of the substation. In reality it is both as you transition from construction or maintenance back to operation.

John Finn, Mark Osborne, Johan Smit

50. Substation Maintenance Strategies

A substantial amount of literature is available from various resources and industries in the field of maintenance management. A comprehensive overview can be found in references [22] and [23]. In this chapter, common terminology and definitions are set out which are relevant and applicable in the field of maintenance management. Definitions are given in IEC 60300-3-14 of 2004 [24]. In IEC 60300-3-14 of 2004, application guide, maintenance and maintenance support, maintenance is defined as: “the combination of all technical, administrative and managerial actions during the lifecycle of an item intended to retain it in, or restore it to a state in which it can perform the required function.”

Ravish Mehairjan, Mark Osborne, Johan Smit

51. Substation Condition Monitoring

Managing substation assets and understanding their performance and condition is a basic fundamental requirement for utilities to deliver a reliable and secure power system. Due to increasing economic constraints, an increasing effort is being made to improve and refine the methods, approaches, or tools for substation asset performance management and condition monitoring.

Nicolaie Fantana, Mark Osborne, Johan Smit

52. Managing Asset Risk and Reliability of Substations

Recently risk assessment is becoming a much more important tool when evaluating the appropriate level of asset intervention. The following paragraphs show the basic procedure for performing a risk analysis and the Failure Mode Effect Analysis (FMEA) which is a basis for the risk investigation [33, 47] in relation to substation assets.

Gerd Balzer, Mark Osborne, Johan Smit

53. Managing Obsolete and New Technologies in Substations Together

The substation lifetime can easily exceed 40–50 years; it is the assets within the substation which have lifetime limiting factors. Changes to the substation will be required during this period and into the future. New circuits may be connected into the substation, which will require additional bays. New transformers may be installed to increase the substation capacity. Aging and broken equipment may need to be replaced.

Jan Bednarik, Mark Osborne, Johan Smit

Future Developments


54. Future Developments in Substation Design

The previous chapters have established the principles which underpin substation design and management. This chapter will highlight some of the medium- and long-term factors that could influence the direction of future substation design. It will focus on changes in the energy landscape and new developments in technology that may challenge the designer in their traditional way of thinking and consequently affect the design process and asset management strategy.

Mark Osborne
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