Research On Operation Overvoltage Characteristic Policy And Suppression Of 220kV Long-distance Power Cable

In the processing of electronic transport,the capacitance of the power cable line is greater than that of the overhead transmission line.At the same time,the cable materials used in 110 k V and 220 k V voltage lines are relatively fixed,mostly cross-linked polyethylene power cables,and the large capacitance per unit length is the characteristic of this type of cable.Relatively speaking,it may be ten times or even more than overhead transmission lines.Dozens of times.Therefore,under such a premise,the dangerous degree of induced overvoltage of power cable lines is more serious than that of overhead lines of the same length.In addition,in the case of long-distance transmission,110 k V and 220 k V equal-voltage cable lines will have greater power frequency overvoltage and operating overvoltage,which may exceed the specified threshold.Therefore,it is of great significance to study the induced overvoltage of the long interconnection of the long cable line of the cross-interconnection during the operation of the power system.The main goal of this paper is the operating overvoltage of long-distance power cable lines,including closing and opening overvoltage.By establishing a transient electromagnetic model of long-distance cable lines and their interconnected systems,study each overvoltage level,and analyze the influence of different factors such as power cable layout,phase angle of opening and closing operations,and cable length residual charge on overvoltage Law,and then suggest the suppression measures for long-distance power cable overvoltage.The research found that for long power cable lines,it is not obviously different between the closing overvoltage and the opening overvoltage in the operating overvoltage,but the closing overvoltage under some serious prerequisites is greater than the opening overvoltage.For closing overvoltage,the closing phase angle and line residual charge have a greater impact on the overvoltage amplitude,the number of bus outlets and the cable length also have a certain effect on the overvoltage,and the cable arrangement mode has a small effect.In the final analysis,the occurrence of switching over-voltage is caused by the arc reignition caused by the lack of arc extinguishing performance of the circuit breaker.In summary,the main measures to control the over-voltage are to install closing resistor,arrester,reactor and improve the arc extinguishing performance of the circuit breaker.