Research On On-line Monitoring Technology Of 10KV Metal Oxide Arrester Fault

The 10 KV zinc oxide surge arrester has become a very important safety protection device for power systems,and its application range is more and more extensive.However,during the operation of the power system,overvoltage surges,moisture inside the arrester,will cause damage to the arrester,resulting in loss of its safety protection.In this paper,a 10 KV zinc oxide arrester fault online monitoring system is designed,which consists of three parts,including arrester leakage current collector,host computer program and data concentrator.It can agilely extract,transmit and analyze the lightning leakage current fault data and locate arrester fault location to improve the efficiency of fault arrest of the distribution network arrester.In this paper,the commonly used lightning arrester leakage current detection technology and their respective technical characteristics are given.Then,the whole design technical scheme of the 10 KV zinc oxide arrester fault online monitoring platform is given in combination with the multiple harmonic method.The arrester leakage current collector and the host computer program and the data concentrator are composed of three parts.The ZigBee wireless communication technology used in the monitoring system is studied.The ZigBee mesh topology is selected,and the electromagnetic current transformer is used as the detection transformer of the arrester leakage current collector.A detection scheme for the leakage current of the arrester is designed.Then,based on the lightning arrester leakage current detection scheme,the hardware and software design of the data collector is carried out.The hardware design mainly includes conditioning circuit of the lightning arrester leakage current,conditioning circuit of the reference voltage,working circuit of the main control chip,module circuit of the power,the ZigBee module,etc.,and finally makes a collector PCB board according to the design of the schematic.The software design of the collector mainly realizes the function of calculating the amplitude of the resistive leakage current of the arrester in real time through FFT,the function of actively uploading the fault data while the resistor leakage current of the arrester exceeding the threshold value,the data transport protocol design of the collector and the concentration,etc.In addition,according to the demand analysis of the data concentrator,the hardware and software design is given,including the main control core circuit,touch display circuit,ZigBee module circuit,SD card storage module circuit,etc,and the PCB board is made based on the schematic diagram.The software function mainly realizes the data communication function,the automatic alarm function and the human-computer interaction function.The concentrator can query the real-time data,historical fault data and collector configuration parameters detected by the collector,and realize the human-machine touch display.Interactive function and storage function of fault data.Finally,the laboratory test of the metal oxide arrester fault online monitoring system can be divided into three parts: collector,concentrator and online monitoring software.Firstly,the collector is subjected to the analog measurement experiment of the low-voltage grid signal,and the accuracy of the detector detection signal is measured.Then multiple collectors and concentrators are used for ZigBee networking and continue query function testing,historical fault data query testing,parameter configuration query testing to verify the accuracy of data,and to verify complete data communication between the entire collector cluster and the concentrator.At the same time,the online monitoring software of 10 KV zinc oxide arrester based on LabVIEW is designed,including three functional sub-modules,namely “arrester polling monitoring”,“single arrester monitoring” and “historical fault data query”.All in all,the test shows that the online monitoring system can meet the needs of on-line monitoring of multi-point 10 KV zinc oxide arrester faults in the grid transmission line.