Research On Line Impedance Analysis Method Based On Grid Metering And Distribution Data Integration

The grid metering and distribution data integration is deeply promoted and applied under the background of the overhaul and large marketing synergy of the State Grid Corporation of China under the "five and three system".As smart measurement equipment is widely installed and used in distribution network,power companies have obtained massive amounts of metering and distribution data.Rational use of these data can provide decision support for the operation and maintenance of the distribution network.Knowledge of the line impedance of Low-Voltage distribution network is a basic of distribution system analysis and intelligent prediction,such as power flow analysis,line loss calculation,control strategy,fault prediction.The accurate impedance value also provides the potential to evaluate the condition of the distribution assets.Power companies have acquired a huge amount of smart metering and distribution data via smart grid implementation in last decade.This thesis provides a method of calculating the line impedance of LV distribution network based on grid metering and distribution data integration.The whole calculation process can be achieved by smart sensors with the edge computing capability.This thesis first introduces a simplified and accurate model of the line impedance of the distribution network and a method for calculating the line impedance in the distribution network.Then,based on the accurate model of distribution line impedance,the line impedance calculation method based on grid metering and distribution data integration is studied.Provided distribution network topology is known,the method utilizes the measurement data in the time series collected by the Transformer Terminal Unit,the Circuit Terminal Unit and smart meters.It uses each customer’s smart meter node data as a calculation starting point.Deriving the distribution line from bottom to top,deriving to the secondary node of the transformer to obtain the voltage value containing the unknown impedance parameter of the line,and so on,so that the node calculated by the different customer smart meter data in the time series is calculated.The mean square error of the voltage value and the actual measured voltage value is the smallest,and the optimal model for solving the line impedance problem is built,and the impedance parameter values of each line are obtained by the action set optimization algorithm.Then an actual distribution network example is used to verify the validity and accuracy of the method for calculating the impedance value of each line.Finally,the application prospects of this method in coastal distribution cable monitoring are qualitatively analyzed and discussed.