Page 101 - Practical Power System and Protective Relays Commissioning

Chapter 8

Air Insulated System Substations

Theory and Testing

8.1 INTRODUCTION
A high-voltage air insulated system (AIS) consists of the following items:
1. Primary plant
a. Heavy current busbars
b. Switchgear, transformers, etc.
2. Secondary equipment
a. Instrument transformers
b. Protection, control, and information systems
3. Infrastructure
a. Civil foundations and structures
Auxiliary systems.As shown in Fig. 8.1 this system uses air as insulating
medium. This has restrictions in the minimum clearance distance required in
order to be safe. For example, for a 220 kV system. the clearance distance is
178 cm for phase to earth and 225 cm between phases. For a 66 kV system
the clearance distance is 63 cm for phase to earth and 77 cm between phases.
Figs. 8.2 8.6 show the components for AIS. Testing of these components
will be discussed in the following chapters.

Practical Power System and Protective Relays Commissioning.
DOI: https://doi.org/10.1016/B978-0-12-816858-5.00008-3 99
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