FAST ACTING DVR FOR THE IMPROVEMENT OF POWER QUALITY USING FUZZY LOGIC.

In modern distribution system, there are a number of voltage-based power quality (PQ) problems caused by substantial pollution and abnormal operating conditions due to non linear load. Some of these voltage-related power quality problems are voltage spikes, surges, flickers, sags, swells, notches, fluctuations, voltage imbalance, current and voltage waveform distortion, and so on. The active series compensators are extensively used to inject the required magnitude of voltage and restore the voltage across the loads. Reference voltage generation and further to evolve the gate pulse required by the DVR for its operation. Ultra capacitor is used in spite of normal capacitor for more energy in short span of time UCAP can deliver more amount of energy with in short span of time..When compared to normal capacitor the charging and discharging time taken by UCAP is very low and life time is very high .The reference voltage generation is to be monitored by controller from time to time .This work presents the discussion of sag mitigation by conventional PI controller and intelligent fuzzy controller. The simulation results are demonstrated using MATLAB software.