Book at a Glance

PART II - Switchgear Assemblies and captive (Emergency) Power Generation

Chapter 13. LV switchgear and controlgear assemblies

• Application
Types of assemblies
Conventional types of switchgear and control gear assemblies (also referred to as switchboards)
Compact switchgear assemblies
Intelligent switchboards
Design parameters and service conditions for a switchgear assembly
Determining fault level of a system and its duration
Energy based discrimination
Deciding the ratings of current-carrying equipment, devices and components
Designing a bus system
Designing a switchgear assembly
HV switchgear assemblies
Protection schemes
General guidelines during installation and maintenance of a switchgear or a controlgear assembly
Power circuits and control scheme diagrams

APPENDIX Painting procedure of switchgear and controlgear assemblies and treatment of effluent

These assemblies (HV or LV) are fitted with switching devices (breakers, switches, fuse switches and contactors etc.), control and measuring instruments, indicating, regulating and protective devices to transform the assemblies into composite units, called control centres to perform a number of functions in the field of distribution and control of electrical power. Some of these functions may be one or more of the following:
1 To control, regulate and protect a generator and its auxiliaries in a power station.
2 To control, regulate and protect the conversion, when necessary, from one voltage to another, in a generating station, a switchyard or a sub-station for the purpose of further transmission or distribution of power.
3 Transmission of power.
4 Distribution of power.

Intelligent switchboards
With the availability of new generation microprocessor based relays and electronic releases (IEDs) for all kinds of breakers Sections 13.5.2 and 19.5.3 a whole switchboard can now be made intelligent like a static drive noted in Section 6.7.4(5). They can supervise and control remotely the parameters of various feeders and thus ease on complexities, achieve low downtimes, controlled operations and better efficiency. By doing continual reactive power management, switching-off feeders operating at no-load, rationalizing loads connected to different sources of supplies and providing required management input support, the intelligent equipment and devices can play a vital role in contributing towards energy saving also. Intelligent boards can monitor and control the power system locally via a laptop computer (PC) and a keyboard. Using telemetry softwares (communication protocols) and media they can be made to monitor and continually improve a process line or execute power management activities from a remote control station.  
Appendix 13.1
Painting of all metallic surfaces of a switchgear or a controlgear assembly or a bus system is an essential requirement of IEC, IEEE, ANSI and all national and international Standards related to such assemblies to provide them with an aesthetic appearance, and prevent from rust and corrosion. Painting serves these purposes by providing the machine with a hard and longer-lasting metallic surface. We describe briefly, the basic procedure to paint and test painted surfaces. In the discussion, we have laid more emphasis on MS sheet-metal surfaces as these are more typical.

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