Analysis And Research On Voltage Of 220kV Line T With High Resistance

In recent years,with the rapid economic development of China’s Xinjiang,Inner Mongolia and other regions,the power load has also increased significantly.In order to alleviate the operating pressure brought by the load growth on the power grid,it is necessary to T connect the original long-distance overhead transmission lines and build a new substation.However,the original long distance transmission lines are often equipped with hV parallel reactors.After T connection,the new lines may be mismatched with the parameters of the parallel reactors,which may lead to the risk of resonant overvoltage and threaten the safety of the power grid and the insulation of equipment.Therefore,it is imperative to carry out overvoltage analysis and research on long distance transmission lines after T connection.The thesis carries out the following research work.Firstly,the 220kV amount line T connection project of Alashan Power Company of Mengxi power grid is analyzed and studied.Corona discharge occurred in the operation process after the money line T was connected,which finally led to the protective action and accident tripping.Through analysis and theoretical calculation,it is found that the parameters of the newly built Jintai line and its high resistance parameters are in the resonance zone after the connection of the amount line T.During the operation of Hongtai Substation,non-full phase resonance occurs when the A phase of the air charging line from Jinnuo Power Station occurs,and serious overvoltage occurs in B and C phases.The analysis conclusion is consistent with the actual phenomenon.Secondly,the BPA software was used to establish the simulation model before the T connection of the money line,and the simulation calculation was carried out under the conditions of normal operation mode and different side high resistance input,etc.,to analyze and study the power frequency overvoltage problem before the T connection of the money line.On this basis,the amount of the line was established based on PSCAD/EMTDC software T pick up after the electromagnetic transient simulation model,considering the jinnuo side empty jintai filling line,guangzhou hongtai busbar empty’s frontal line filling and normal operation mode,different ways of maintenance,and so on and so forth,the simulation to study the single-phase circuit breaker operation over-voltage,resonance overvoltage and jumped after the power flow and the recovery voltage,finally gives the amount of the line after T meet the high economic configuration scheme.With high line is proposed in the end,T meet high choose the general process of substation engineering method,namely in the process of power grid design trends and overvoltage calculation analysis was carried out on the grid,according to the power grid reactive power balance,overvoltage level and economic benefit factors determine high configuration scheme,and start the plan formulation,provide the basis for the operation.