Feeders High voltage

Size of substations must be chosen with care. As size is reduced, more material is required for high-voltage feeders, transformers, and switches. However substations supplying too great an area will increase secondary circuitry costs. This is again an economic balance. Optimum power ratings for a three-phase substation are 400 to 600 kva with 208/120 or 230-volt secondaries and 600 to 1,000 kva with 460-volt secondaries. 

The following description of integrated motor control systems (IMCS) is based upon Reference 7, for which permission to use the material therein was kindly given by Switchgear and Instrumentation Ltd. The principles described can be used for low and high voltage switchgear that contain plain feeders, interconnectors, incomers and busbar section circuit breakers, in addition to... 

For high voltage cables, and low voltage feeder cables between switchboards, the disconnection time can be reduced from 5 seconds to not less than 0.2 seconds. The time of 0.2 seconds is determined from the total clearance time of a circuit breaker protected by a fast acting overcurrent relay. For high voltage motor circuits in which the short-circuit protection is provided... 

PCC Point of Common Coupling is usually referred to the main feeder of the plant, usually (but not necessary) high voltage. This point is of concern for meeting utility specific harmonic requirements. 

Distribution substations serve as the source for primary distribution feeders. They receive bulk electric power at high voltages and reduce the voltage to distribution primary values. Also associated with a substation are provisions for protection from faults, for voltage regulation, and for data acquisition and monitoring. 

Substation It serves as the source for primary distribution feeders. Receives bulk electric power at high voltages and reduces the voltage to distribution primary values. 

For cables having long route lengths the associated volt-drop may cause the margin in cnrrent capacity to be reasonably high, especially with low voltage feeders. 

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