Research & Application Of On-line Device For Monitoring Overvoltage In 10kV Distribution Network

Overvoltage on-line monitoring is a part of on-line monitoring technology,which is for monitoring overvoltage in power system.With development of electric network,more and more people realize effect of overvoltage for safety of electric network is important.Becauce 10kV distribution network is used to supply power for user directly, its distribution is extensive, equipment is more and electric insulation level is low,it is easy that overvoltage accident occur. Overvoltage occur frequently and causes great damage in lOkV distribution network,especially in the system whose neutral-point doesn't earth. Because some overvoltage result in great economic loss ,system resume difficultly and long time power cut,overvoltage on-line monitoring is very necessary for operation in lOkV distribution network.Familiar on-line monitoring device for overvoltage just monitor inner overvoltage,but the device introduced in the paper can monitor lighting impulse overvoltage and inner overvoltage in lOkV distribution system.With the characteristics of overvoltage in the lOkV distribution network,the principle of on-line device for overvoltage monitoring is introduced.Divider,coaxial line,trigger,signal processing,data acquisition, acquisition control and waveform analysis software is included in the device.When the device operate in the system ,overvoltage is transferred to coaxial line by divider.If the. overvoltage amplitude is higher than initialization value,data acqusition card start sampling.When sampling is over,computer save data to file. Engineer can analyse parameter of waveform by appropriative software reading data from file.In the trial measurement,the device shows good performance.simulant trial and actual result indicate that method in the paper acquire approving effect,and the device can be used in the lOkV distribution network.