Voltage and Power Factor Control of 66,000-Volt Transmission Lines Connecting Two Generating Stations

The problem which confronted The Philadelphia Electric Company of providing for the control of voltage and power factor of the two 66,000-volt transmission lines connecting its Schuylkill and Chester generating stations is presented in this paper. It is required that the control of voltage and power factor of the transmission lines referred to permit of the transfer of energy in either direction, at suitable power factor, up to the rated kv-a. capacity of the lines, with the generating stations operating at approximately equal bus voltages. The situation is considerably complicated by the necessity for supplying energy to several industrial substations, connected to these lines near the midpoint, which under certain operating conditions are supplied from one of the two lines. Another important factor in the selection of regulating equipment is the severe short-circuit effects possible in a system of which the ultimate capacity of the present three generating stations will be approximately 500,000 kv-a. The comparison made to determine upon the most satisfactory type of regulating equipment and the reasons for the selection of three-phase induction regulators are given. Data on the performance characteristics of the lines, with the induction regulators are included. In the discussion of this problem of voltage and power factor control, certain conclusions of a more or less fundamental character are brought out.