Benefits of Line Capacitors Extended by Remote Automatic Control

The application of pole-mounted capacitors up to the economic limit for the system is practicable with the control system here described. The proper application of controlled capacitors requires an awareness of the several possible benefits and their relationship to the system problems being faced. For example, the master substation system shown in Fig. 1(A), when ultimately developed to a 100,000-kw load or more, may justify a total of 60,000 kvar of switched capacitors. Due to voltage interaction among banks, the total voltage correction obtainable at the banks will then exceed 14%. Since the voltage gradient over the system is quite different from that with tap-changing control, this 14% is equivalent to a considerably greater range of tap changing. The successful application of capacitors to a system permits the combination of unswitched capacitors for light-load correction with switched banks to care for load variations. Remote control is most readily justified on larger substations and does not eliminate the use of time control or other local automatic control for the solution of spot voltage or thermal problems.