4
-1
0-8493-1703-7/03/$0.00+$1.50
© 2003 by CRC Press LLC
4
High-Voltage
Switching Equipment
4.1
Ambient Conditions ..........................................................
4
-1
4.2
Disconnect Switches...........................................................
4
-1
4.3
Load Break Switches ..........................................................
4
-2
4.4
High-Speed Grounding Switches ......................................
4
-2
4.5
Power Fuses.........................................................................
4
-3
4.6
Circuit Switchers ................................................................
4
-3
4.7
Circuit Breakers ..................................................................
4
-4
4.8
GIS Substations ..................................................................
4
-6
4.9
Environmental Concerns ...................................................
4
-6
References ......................................................................................
4
-6
The design of the high-voltage substation must include consideration for the safe operation and main-
tenance of the equipment. Switching equipment is used to provide isolation, no load switching, load
switching, and/or interruption of fault currents. The magnitude and duration of the load and fault
currents will be significant in the selection of the equipment used.
System operations and maintenance must also be considered when equipment is selected. One signif-
icant choice is the decision of single-phase or three-phase operation. High-voltage power systems are
generally operated as a three-phase system, and the imbalance that will occur when operating equipment
in a single-phase mode must be considered.
4.1 Ambient Conditions
Air-insulated high-voltage electrical equipment is generally covered by standards based on assumed
ambient temperatures and altitudes. Ambient temperatures are generally rated over a range from –40°C to
+40°C for equipment that is air insulated and dependent