Research On Fault Analysis And Bad Data Identification Method Of Telemetry Circuit In 500kV Conventional Substation

Substation plays an important role in the whole power system,which is mainly composed of primary system and secondary system.The fault of remote communication and telemetry equipment and the error of data in the secondary system of substation may bring huge security risk to the power grid.In the actual power grid,many conventional substations do not have intelligent function,and there are prominent problems such as old secondary equipment and high failure rate.However,the existing researches mainly focus on the identification of telemetry bad data based on the whole network data of the dispatching center,without fully considering the influence of the primary wiring mode of the substation and the concrete structure of the secondary system on equipment failure and bad data identification.Therefore,aiming at the above problems,this paper conducts fault analysis on telemetry circuit of 500 k V conventional substation in Chongqing,and studies the identification methods of telemetry bad data respectively.The main contents and results of this paper are as follows:(1)Based on the conventional substation secondary system structure,the schematic diagram of telemetry circuit is established.According to the working principle,hardware composition and software configuration of related secondary equipment in the telemetry circuit,the influence of faults of each secondary equipment component unit on telemetry data is analyzed.It is concluded that different types of unit faults will lead to single bad telemetry data,multiple bad telemetry data with correct telemetry,multiple bad telemetry data with no telemetry refresh,and bad telemetry data.(2)An identification method of telemetry bad data based on power residuals and voltage residuals of substation nodes is proposed.According to the power balance relation of substation nodes and the principle of voltage consistency,the residual equation of power and voltage measurement is designed based on the primary connection mode of substation.At the same time,based on a large number of historical measurement data of the substation and the principle of 3 times standard deviation,the residual thresholds of power and voltage are calculated and taken as the criterion of residual overcrossing,so a method to identify the telemetry bad data of the substation is proposed.In addition,the relevant methods can effectively identify the active power and bad data of reactive power,bad or suspicious data of bus voltage,and bad or suspicious data of telemetry of main transformer,which are verified based on the measured data of Chongqing 500 k V CJQ substation.(3)A bad data identification method of busbar switch position signal considering power distribution relation of main transformer in parallel operation of substation is proposed.Based on substation connection mode at a time when run in parallel with main transformer equivalent circuit model,combined with the ring network tide distribution calculation method and the Ward equivalent method,two and three is deduced respectively three winding transformer run in parallel with high,medium voltage side of active power distribution relations,which is presented based on the main transformer high voltage side of active allocation proportion bus coupler switch state criterion.In order to verify the effectiveness of the proposed identification method,not only the power flow simulation of a typical example is used,but also the actual data of Chongqing 500 k V CJQ Substation are used to verify the method.