Effect of increased electric loads on primary substation equipment in 100-B, C, D, DR, F, and H areas

摘要

The loading on the primary transformers which step down the 230 kv transmission voltage to a distribution voltage of 13.8 kv, at 100-B-C, 100-D-DR, 100-F, and 100-H Areas will be increased by the synchronous motors now being installed in those areas under Project CG-558. This report summarizes: The changes in electric loads (both kv and power factor) which will result when the new motors are placed in service and certain older motors are withdrawn from service. Electric loads are tabulated in section 4.0 for each area for present conditions, the planned changes and the post-CG-558 conditions. The reduction of distribution voltage during the starting of individual 4500 hp synchronous motors. Since the synchronous motors will be started across the line as induction motors, the starting current will be high, and at a low power factor. Voltage drops are calculated for the starting of a synchronous motor, with one and then with two transformer banks paralleled. The current-interrupting capacity of switchgear vs. the maximum short-circuit current which could occur with separate transformers and with two primary transformers in parallel.