Handbook Of Switchgears Bhel Pdf UPDATED
kind in India, and one of the leading international companies inthe field of power equipmentmanufacturing. BHEL startedmanufacturing switchgears in 1961 and has since made significantstrides inthe field. In this book, efforts have been made toreflect and put forward the vast experience and expertisegained byBHEL over these 44 years. The book fulfils the long felt need ofpracticing power engineers,who had otherwise to refer to severalarticles to solve their various queries on switchgeardesign,application, and protection. It makes clear that the choiceand use of switchgear is far from standard, andthat a thoroughknowledge of the matter is a must.
Handbook Of Switchgears Bhel Pdf
The book covers not only the general concepts but also providesconsolidated information onswitchgears in the context of Indianconditions. This approach is beneficial for the utilitiespractisingengineers. Starting from the basics, it enables evenengineering students to understand the subject. Thetopics of eachchapter have been skillfully selected and cover all aspects ofswitchgears.
Chapter 3 deals elaborately with medium voltage switchgearsrated from 3.3 kV to 33 kV class andprovides information aboutvarious forms of construction in metal enclosed, metal clad andporcelain claddesign. To bring more clarity on constructionalaspects, the definition of various terms have been takenfromrelevant IEC and IS. Present and future trends in medium voltageswitchgears have also beenexplained.
The theory, design and constructional aspects of instrumentstransformer along with application andtesting requirements havebeen fully covered in Chapter 7. The details of instrumentstransformer testingand analysis of testing results along withstandardisation and cost considerations have been providedbased onBHEL experience and expertise gathered during long association withswitchgears.
Chapter 10 strives to explain various aspects of application ofmedium voltage switchgear andhighlights the considerations forselection of suitable circuit breakers for different applications.Thedetails given are based on BHELs rich experience in the field ofswitchgears.
Protection schemes for medium voltage switchgears have beendealt with in Chapter 13 and cover allprotection aspects. Thedetails are expected to provide an insight to beginners andstudents of protectionphilosophy.
The book reflects the expertise gained by BHEL in the field ofswitchgears and offers a wide andthorough coverage. The work hereis informative as it follows a practical approach and highlightsallsalient features of switchgear. I am confident that the bookwill serve as a useful reference for allpractising engineers andstudents.
This book is a result of collective effort of experts in thefield of switchgears at BHEL, a leadingswitchgear manufacturer inIndia. Thanks are due to all the authors who took pains andcontributedchapters to it.
Switchgears are necessary at every switching point in the powersystem for the reasons mentionedabove. There are several voltagelevels and fault levels between the generating stations and finalloadpoints. Hence in the various applications, the requirements ofswitchgears vary depending on the location,ratings and localrequirements. Besides the supply network, switchgear is required inindustrial works,industrial projects, domestic and commercialbuildings.
BHEL has very wide experience in the field of design,development, manufacturing, type testing,installations,commissioning, operation and maintenance of various types ofswitchgear equipments.During the last four decades, the switchgearindustry has seen the transition of four switchingtechnologies,viz. those involving air, oil, gas and vacuum.Finally, the emergence of environment-friendly vacuumtechnology inmedium voltage switchgears and of SF6 gas technology in highvoltage and gas insulatedsub-station (GIS) promises bringstability.
This book on switchgear from BHEL covers the industrysexperience of the last four decades in thefield of medium and highvoltage switchgears, GIS, associated equipments, and control andprotectionschemes for generation, transmission and distributionapplications.
The technological aspects of medium and high voltage circuitbreakers ranging from 3.3 kV to 800 kVclass are dealt with inChapter 1. The technological backgrounds and advantages of variousswitchingtechnologies, viz. those involving air, oil, gas andvacuum are elaborately discussed. Arc energy and arcquenching playa very important role in an interrupting media. The arcingphenomenon is dealt with indetail to understand and establish thesuperiority of a technology. Different types of mechanismsviz.spring, pneumatic, hydraulic, electrical and magnetic are beingused for opening and closing of the circuitbreakers. The type ofmechanism in a circuit breaker depends upon the energy and speedrequired for arcinterruption. Being simple and economical, thespring mechanism has been popular in both medium andhigh voltageswitchgears. Magnetic actuators are now being introduced in mediumvoltage circuit breakersup to 12 kV, 40 kA due to their inherentadvantages of long life, suitability for a large numberofoperations, maintenance-free operation and smaller number ofcomponents.
Switchgears for low voltage applications are rated up to 1000 Vac and 1500 V dc. Oil circuit breakers(OCBs), air circuit breakers(ACBs), switch fuse units (SFUs), off-load isolators, HRC fuses,earthleakage circuit breakers (ELCBs), miniature circuit breakers(MCBs) and moulded caste circuit breakers(MCCBs) are the commonlyused devices in low voltage switchgear. The requirements ofconventionalswitchgears and new trends for various applicationslike incomers, sub-incomers and feeder protectionsare brieflydiscussed in Chapter 2.
Switchgears for medium voltage applications are rated from 3.3kV to 33 kV class. Medium voltageswitchgears are mainly used forthe distribution of electrical energy connected to variouselectricalnetworks. Chapter 3 deals elaborately with the historicalbackground of minimum oil circuit breakers, bulkoil circuitbreakers, air magnetic switchgears, SF6 gas insulated switchgears,and the latest trends invacuum switchgear and gas insulatedswitchgears. This chapter also provides information aboutvariousforms of construction in metal enclosed, metal clad andporcelain clad design. The design aspects, relatedto currentrating, temperature rise limits, short-circuit currentrequirements, vibrational stresses andinsulation aspects arecovered elaborately.
High voltage circuit breakers ranging from 66 kV to 800 kV classare covered in Chapter 4. Thischapter deals with the historicalbackground, present status of technological developments and thefutureoutlook of high voltage switchgears. This chapter alsoprovides insight into various interrupting media likeair, oil andSF6 gas which have been successfully used in the development ofhigh voltage circuitbreakers. The latest trends in the design ofSF6 gas circuit breakers and operating mechanisms arealsodiscussed. System requirements covering important duties likeshort-circuit (terminal fault), short linefault, transformermagnetising current, energisation and breaking of long transmissionlines, breaking ofcapacitive current and out-of-phase switching arealso elaborately discussed in this chapter.
The requirement of gas insulated metal enclosed systems isspecified in IEC 517. Sub-stations andswitchyard equipments likecircuit breakers, disconnectors, earth switches, busbars, CTs andPTs aremetal encapsulated and pressurised with SF6 gas. Chapter 5details the design and manufacturing aspectsof variouscomponents/assemblies of GIS system used in both the medium andhigh voltage class ofswitchgears. The use of GIS equipments reducesrequirement for space and improves reliability, thusincreasingtheir popularity for application in metro cities and hydro stationswhere the costs of space andconstruction are very high.
Auto reclosures and sectionalisers are used in the distributionnetworks of medium voltage switchgearsupto 33 kV class. Theseequipments are useful for the fast automatic restoration of supplyfollowingtransient faults in the system due to frequent lightningsurges and in areas where power lines run throughforests and trees.These equipments are extensively used in the continents of Americaand Australia dueto their distinct advantages over conventionalswitchgears. Although this product has not yet gainedpopularity inIndia, it has great potential for rural electrification and powerdistribution to important loadcentres in India. Chapter 6 isentirely devoted to this topic in view of its potential importance.Thischapter deals with the technical specifications, construction,and technological aspects of auto re-closuresand sectionalisers,along with case studies for various applications.
Surge suppressors/arrestors are very important components ofswitchgears and sub-station installations.These are used to protectthe sub-station equipments from temporary over-voltages, switchingimpulses,and lightning impulses, and to a certain extent, very fasttransient over-voltages. Historically. spark gapswith airinsulation were used as surge suppressors. Lightning arrestors,surge capacitors, surge suppressingreactors, and thyrite resistorswith series gaps were used in the past for this purpose. Innovationin thisfield has resulted in the advent of two commonly used types,viz. the metal oxide-based (ZNO) type andC-R type of surgearrestors/ suppressors. Chapter 8 deals with the various types ofsurge arrestors, theircharacteristics, and construction andapplication aspects.
When a switchgear has to be applied in an electrical powersystem, certain considerations need to bekept in mind regarding thelocation of the equipment whether indoors or outdoors, systemparameters(system earthing, frequency, insulation level, ratings,ambient conditions), etc. These are detailed inChapter 10, whichdiscusses the application of medium voltage switchgears. Therequirement ofswitchgears for various applications in a generatingstation, transmission sub-station and distributionsystem are alsodetailed in this chapter. 350c69d7ab