Research On On-line Monitoring Technology Of Anti-tampering For Energy Metering Circuit

Electricity measurement is the electricity settlement between the power generation enterprise,power supply enterprises and power customers,the accuracy of measurement is necessary to ensure the electricity order.However,in order to obtain higher profits,some power customers risk personal safety to destroy the measurement device to achieve the purpose of stealing.In the past,the phenomenon of stealing is particularly serious,power supply enterprises have taken many technical measures and management,and achieved good results,but the current anti-tamper technology is still inadequate.One,can not detect simple and secret underflow law to steal electricity;Second,the wrong meter wiring analysis still relies on manual investigation,can not achieve automatic monitoring;Third,can not provide a comprehensive anti-tamper technology.Therefore,the research of this paper mainly includes the following aspects.This paper analyzes the stealing faults in high voltage three-phase three-wire circuit in detail,and studies the detection technology of various faults.In this paper,the failure characteristics of voltage transformer disconnection are analyzed,and the threshold method is used to determine whether the voltage circuit has broken fault.In this paper,the change of the impedance of the current transformer and the secondary circuit is analyzed,and the impedance of the circuit is detected by high frequency admittance.The feedback circuit is used to determine whether the current circuit is fault and types of fault;For the phase shift method to steal electricity,sort out the wrong type of wiring,use phasor diagram analysis the voltage and current which access to the energy meter,to determine the specific form of wrong wiring.By use the matlab/simulink,the simulation results show that the high frequency admittance method can judge the state of the current transformer.At the same time,the influence on the feedback voltage of the frequency,the primary and secondary winding inductance of current transformer,and load are analyzed.The simulation results show that the feedback voltage is not affected by the primary winding inductance of the current transformer and the primary system load;For the same current conditions of the current transformer,the feedback voltage will increase with the high frequency signal frequency increases;When the current transformer is in the normal and primary short circuit,the feedback voltage will increase with the increase of the secondary winding inductance of the current transformer,and not affected when the current transformer's secondary winding is in open/short circuit.In this paper,the anti-tampering terminal is designed by using PIC16F877 A and ATT7022 A.Which ATT7022 A measure the amount of electrical information,PIC16F877 A determine the specific failure.And have tested the device in the transformer laboratory and indoor test room of the measurement center in Sichuan Province.The test results show that the terminal can accurately determine the voltage transformer disconnection,the open and short of the current transformer's primary,the secondary side and the wrong form of the wrong wire.It can effectively monitor the state of the metering circuit,which is to a comprehensive anti-tampering.The research of this paper has a high engineering application value,which provides an accurate,reliable and practical solution for the anti-tamper technology of electric energy metering.