A proposed algorithm for reactive power & voltage coordination in distribution systems using fuzzy technique

Abstract EN

-Abstract This method finds the Under Load Tap Changer (ULTC) position and capacitor ON/OFF status of each hour for the next day in main or secondary distribution substations, so the secondary bus voltage improves and the reactive power flow into the transformer can be restrained at the same time.

The only condition to achieve these goals is the previous knowledge (by forecasting) of load demand for active and reactive power and the primary bus voltage for each hour of that day.

The practical constraints are involved through the use of membership concept in fuzzy set theory, where these constraints are bus voltage limits, the tolerable worst power factor & the maximum allowable number of switching operations for the Load Tap Changer (LTC) and capacitor in a day.

This method is also considering the variation of load active & reactive power with its voltage, where the loads are classified into three categories according to their relationship with voltage, and so there are constant impedance loads, constant current loads and constant power loads.

To demonstrate the usefulness of this method an example on one of the Iraqi national grid substations (132/33KV Yarmook substation) was made in MATLAB.