Online Corona Losses Investigation During Overcast In Real 500 KV TLS Based On PMU Data

Phasor measurement units (PMUs) and wide area monitoring systems (WAMS) are undoubtedly the important technologies in power systems [1]. One of their implementations is online parameter identification using current and voltage phasor vectors from sending and receiving ends [2]. Transmission line (TL) parameters online updating could help to solve different tasks, such as state estimation, power flow analysis, and Q/V optimization. The updated TL parameters could provide the data to identify the fault localization. Using FACTS devices gives a possibility to automatic control the operating voltage along the TL [3]. For the task of Q/V optimization not only active resistance updating is required but also renewing the corona losses (CL) value and the dependence between CL and operating voltage (OV). It is well known that instant CL value depends heavily on the weather conditions (wind velocity, air humidity, ambient temperature, precipitation, etc.) along the TL and on the voltage profile along the line. Due to the challenge in commercially installing weather stations along the TL, TL parameters identification based on PMU measurements is the most viable and effective solution. There are some papers considering CL and OV relation as a quadratic function due to a pi-circuit [2], [4]. These papers suggest defining CL from TL conductance. It has been established that real dependence between CL and OV constitutes the 4-8 order polynomial [5]. Given that, the better the weather is, the higher the order is observed.