Fuzzy Expert System for Main Transformer's Tap Changer to Control Voltage and Reactive Power

The main transformer's tap changer, which maintains the voltage and reactive power at a constant level on the secondary side of the transformer, must be inspected after a certain number of operations. This paper outlines a new voltage and reactive power control system that prevents unnecessary tap changing of main transformers by predicting the near-future voltage and reactive power. Control equipment that incorporates this control algorithm has been manufactured for and applied in the Noshiro Thermal Power Plant.