VOLTAGE IMBALANCE SUPPRESSION DEVICE FOR DISTRIBUTION SYSTEM AND VOLTAGE IMBALANCE SUPPRESSION METHOD OF DISTRIBUTION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a voltage imbalance suppression device for a distribution system by which a voltage can be maintained proper even in a system where voltage imbalance occurs.SOLUTION: The voltage imbalance suppression device comprises: a step voltage regulator (SVR) installed in the middle of a distribution system so as to monitor voltages of all three phases at a secondary side and in a terminal of the distribution system; and a phase static capacitor (SC) for power factor improvement installed closer to the terminal of the distribution system. A voltage difference between a phase of a highest voltage (maximum phase) and a phase of a lowest voltage (minimum phase), among the voltages of the three phases, is determined and when the voltage difference is great, the number of the phase static capacitors (SC) to be thrown in for the minimum phase and the number of the phase static capacitors (SC) to be opened for the maximum phase are determined so as to reduce the voltage difference. After the voltage difference is suppressed by controlling the phase static capacitor (SC), the voltage is maintained within a proper range by the step voltage regulator (SVR).