Switching Phenomenon in Six-Phase Transmission System

摘要

Converting a three-phase transmission line into a six-phase one is one of the feasible approaches to increase the power transfer capability of existing three phase double circuit transmission networks. However, this will impact the existing tower insulation. One of the main concerns is switching overvoltages that occur in transmission lines due to the opening and closing of circuit breakers. This paper aims to investigate into the switching phenomenon that would occur in a six-phase transmission system. Till now such an investigation using a laboratory replica of a practical transmission network is yet to be reported. In this work one of the transmission lines belonging to the Malaysian national utility i.e., Tenaga Nasional Berhad's (TNB) has been investigated as a six phase line through simulations as well as an experimental prototype. It is the 113.1 km long 132 kV three-phase double circuit transmission line between Gua Musang and Kuala Krai in Kelantan, Malaysia. A comparison between simulation and experimental results is also given. The work is expected to enhance the understanding of the changes in switching overvoltages due to conversion of a three phase transmission line into a six-phase line.