Method for Improving Power Quality in Distribution System by Static Capacitors based on Power Line Loss

Abstract

Recent rapid introduction of photovoltaic power generations (PVs) causes several issues of power quality. First, reverse flow causes voltage rise of distribution lines. Second, since almost of residential PVs are connected to the distribution lines by single-phase, voltage imbalance is occurred by imbalance current of PVs. On the other hand, in Japan, almost high voltage consumers set up Static capacitors (SCs) to improve the power factor at their receiving points. However, the capacity of SC becomes excessive than required amount of capacity. Hence, the excessive amount of SCs may also cause voltage rise and harmonic voltage problems that is Ferranti Effect and harmonic resonance between SCs and inductance of lines.
Under these backgrounds, the purpose of this study is to propose the new control method of SCs not only improving power factor but also solving power quality problems. The major point of the proposed method is to determine the capacity of three-phase type SCs and single-phase type SCs so as to minimize power loss of distribution line in a limitation condition of each power quality.