Corona Discharge Numerical Analysis Of High Voltage Transmission Line

With the high speed development of economy, nowadays, electrical power requirement is becoming very urgent in China. In order to increase the transport capacity of HV transmission line and decrease its electric energy waste, a lot of extra high voltage and ultra high voltage transmission lines are already being built. As the voltage increases, corona discharging on the surface of transmission line will appears. Corona discharge can create noise and electromagnetic interference pulse, and cause electrical energy losing. Therefore, studying corona discharge character in different conditions is necessary. In this dissertation, effects to corona discharge caused by burr and raindrop, and by space charge created from corona discharge itself have been studied.Transmission lines can be abraded because of friction and collision in the courses of manufacture, transport, and lines building, these will create some fine burrs in the surface of transmission lines. After simulating and calculating the electric field of transmission line model with burrs, the conclusion shows that the electric field intensity in the burr surface is nearly 20 thousand times more than the electric field intensity in the smooth surface. This can illustrate the reason why the corona discharge in burr surface is very intense. In rain and fog weather, transmission line's corona discharge is more intense than in sunny weather. After simulating and calculating the electric field of transmission line model with raindrop, the result shows that raindrop causes transmission line's surface electric field distorting, and increase the electric field maximum, this lead to the corona discharge becoming intense. Corona discharge can create a lot of space charge, space charge's electric field also effect corona discharge. After building space charge model and calculating its electric field value, the fact is that space charge electric field can decreases the total electric field intensity and suppresses corona discharging. This fact can give a good explanation for electromagnetic interference impulse's appearance mechanism. The research results in this dissertation supply some valuable data for researching other characters of transmission line's corona discharge, and give some valuable reference for farther recognizing and studying the corona discharge phenomena of transmission line.