STATCOM Based Network Voltage Unbalance Mitigation for Sub-Transmission Networks

Network voltage unbalance (VU) is a potentially damaging power quality phenomenon for both utility and end consumer equipment. With the increased penetration of disturbing loads such as electrified railways, single phase distributed generators and line-to-line connected industrial loads, VU levels can be exacerbated. Consequently, network operators are increasingly diligent in maintaining the network-wide VU within stipulated limits. VU management in general, is a synergy of a number of tasks covering proper planning, operation and application of active VU mitigation techniques. Application of power quality conditioning equipment such as static compensators (STATCOMs) at appropriate locations is one such unbalance mitigation technique, which can be seen in practical networks. This paper gives a comprehensive analysis of STATCOM based VU mitigation taking into account the influence made by location and the impedance of STATCOM and comparatively evaluates the management and mitigation techniques of VU with respect to a practical 66 kV sub-transmission network.