Research On On-line Detecting Method Of 10kV Electric Energy Metering Device

The accuracy of energy metering is an important prerequisite for establishing fair electricity market.The state stipulates that energy metering devices must be regularly inspected and calibrated.Presently,due to the feature of overall packaging of 10 k V integrated metering devices,replacing the meter periodically only cannot be implemented.In order to avoid the loss caused to the electric power industry and the excessive workload of disassembling the measurement box,the online operating status detecting system of 10 kV power metering device was presented.The on-site calibration channel of the designed 10 kV electric energy metering device online detecting system in this thesis is combined with the voltage sense module,current sense module and the energy metering module.The calibrated channel which made up by checked metering device is switched in power line with the modules at the same time.The utilization of the device achieves dynamic data collection towards 10 kV power grid.The online detecting system convert high-voltage signal and high-current signal to millvolt level signal and milliampere level signal through partial pressure resistance network and split core type current transformer.The system send them into the energy metering chip ADE7878 for internal processing,then the signal would be put into the algorithm module for comparison along with the dynamic data read by the inspection metering device.The calibrated channel device of on-line measurement without power outage is not able to reach the demand of two class of accuracy higher than the calibrated channel.So the calibration channel cannot be utilized as a standard channel in the strict sense,it can only get close to the standard channel through calibration as close as possible.This paper presents a similarity evaluation method based on dynamic trend change.The system gets data of similarity of multidimensional of power,voltage and current data of the calibration channel through calculation and combined with dynamic time warping algorithm,the energy trend changing problem can be switched into the pattern distance problem in space.The similarity of the sequence could be identified and then the operating status level of the metering device could be determined.Finally,the system and the method proposed in this paper are preliminarily tested.The results show that the system designed in this paper can realize on-line evaluation aims at 10 kV electric energy metering device on the condition of active power level 0.5 and reactive power level 1.0.