Research on the Voltage Phase Shift Phenomenon of 35kV Transmission & Bypass System and Solutions

With the increased reliability requirements of 35kV transmission system, uninterruptible power supply maintenance has become a popular and trending issue. As an important part of uninterruptible power supply maintenance, the bypass operation method occupies a very important position in the field of 35kV transmission maintenance. This paper analyzes the existing safety weaknesses for the existing 35kV bypass maintenance system. It was found that when one end of the bypass cable was connected to the beginning of the service transmission line, there was a voltage phase difference between the other end of the bypass cable and the end of the service transmission line. This is mainly caused by the power flow in the transmission line. It is practically vital but there are few articles analyzing such phenomenon. For this phenomenon, two solutions are proposed in this paper: adjusting power flow in the transmission line, supplementing reactive power at the end of the cable. It is found that as the load reactive power in the transmission line increases or the capacitance value of the reactive power compensation device on the cable increases, the voltage phase difference of the transmission line and the cable decreases first and then increases. This paper provides an important guarantee for the safe operation of uninterruptible power supply technology on 35kV transmission.