Voltage control improvement through capacitor and transformer tap optimization

The authors present a study of the existing and planned voltage control devices on the Ohio Edison (OE) transmission and subtransmission system. These devices included 104 transformers, most of which are fixed tap, and over 100 sites for new or additional capacitor bank installations. The intent was to determine the transformer tap settings and reactive allocation to provide the best possible voltage profile for all foreseeable system conditions while minimizing losses and reactive imports. Due to the large number of voltage control devices being studied, an optimal power flow (OPF) was used for most of the analysis. The use of an OPF eliminated a significant amount of the trial and error work normally associated with this type of study. This study demonstrates the benefit of an OPF for transmission planning studies in addition to previously demonstrated system operation benefits