Research On The Temperature Field Of Single Core Ultra High Voltage (UHV) Shunt Reactor

The development of ultra high voltage(UHV)long distance transmission technology is not only the direction of development of electric power industry at home and abroad,but also the inevitable demand of Chinese national conditions.UHV shunt reactor is important to the UHV technology,because it can balance the reactive power so as to improve the voltage distribution on the alternating current(AC)UHV transmission lines.So the market of UHV shunt reactor has broad prospects,and the manufacturers have accelerated the pace of its development and manufacture.However,UHV reactors in the actual operation,occurs faults frequently,which are caused by the local overheating.What's worse,uneven temperature field distribution will also lead insulation aging,loss increase and reduce the life and performance of UHV reactor.Based on the above reasons,the research on the temperature field of UHV shunt reactor receives much more concerns.Two core and single core styles are two common structures of UHV shunt reactors.Single core structure has the advantages of small volume and low cost,which compared to the two core structure on the capacity of the same voltage level.Therefore,this paper focuses on the single core UHV shunt reactor.Reactor heat source brings loss to electricity and magnetic.Meanwhile,the special iron core air gap structure and single winding structure lead to a large proportion of leakage flux and magnetic leakage loss increasingly,which easily to cause local overheating phenomenon.In this paper,the mechanisms of reactor magnetic flux leakage are analyzed in theory.The magnetic field simulation was carried out on 240 Mvar,1100 kV and 200 Mvar,1100 kV high voltage shunt reactor,and found out the magnetic density area.The reactor heat dissipation mechanism and temperature rise engineering calculation method are studied and the UHV parallel reactor's three-dimensional model is established.The finite element method is used to simulate the internal temperature field of the reactor,and find the local temperature overheating area located in the core rod screw hole,coil,core,core clip,etc.The temperature rise test was carried out in two UHV parallel reactors.The platinum resistance temperature measurement components,the measurement of winding direct current(DC)resistance,the gas chromatographic analysis of transformer oil,the infrared camera imaging and other methods were used in the test.The optical fiber temperature sensor was installed in the easily overheating area,and the internal temperature of the reactor was measured and the test data were calibrated and processed directly in self-cooling and air-cooling modes.The simulation results of the reactor temperature field were verified by the test.Finally,the improving methods of the leakage magnetic field and temperature field of the various UHV shunt reactor components were summarized,including the improving design on the reactor body structure,assembly and its components,and the omnidirectional magnetic shielding system,which provided a reference for improving the performance and reliability of the UHV parallel reactors.