Research On Calibration Method For Instrument Transformer Based On PMU

Instrument transformer provide voltage and current signals to all the monitoring and control equipment.Those with deviation can lead to biased measurements,and affect subsequent application.Taking the ratio correction factor of instrument transformer as the research object,a method of deviation detection is studied to evaluate the status of the instrument transformer.Then,a calibration algorithm is studied in view of the influence of the uncertainty and noise of the system.Finally,a fusion method of PMU and SCADA data is studied to form a method of detection and calibration of instrument transformer deviation based on hybrid measurement.Aiming at the problem of instrument transformer evaluation and selection of reference for calibration,a system parameter model with transformer deviation is established,and the influence of line parameter error is analyzed.A method of instrument transformer deviation identification based on DBSCAN is proposed,which can realize calibration preprocessing in case of line parameter error existing.Instrument transformer with deviation can be determined,and the reference for calibration is selected,which establishes the foundation for the high-precision calibration of the instrument transformer.Aiming at the problem of poor anti-interference ability of calibration algorithm,a calibration model is established,and the influence of uncertainty and noise of the system is analyzed.The H-infinity filtering method is introduced,and the dynamic calibration model is designed.A transformer calibration method based on H-infinity is proposed,which can realize the high precision calibration of transformer under the influence of system parameter error and noise,enhancing the robustness of the algorithm to model uncertainty and unmodeled noise.Aiming at the problem that the lack of PMU data limits the application of calibration method,this paper analyzes the difference between PMU and SCADA data,reveals the compatibility of the two kinds of data in the aspects of phase angle,synchronization and accuracy.The fusion method of the data is designed,and the method of calibration of instrument transformer deviation based on hybrid measurement is proposed.The proposed scheme can detect and calibrate the deviation of instrument transformer when system-wide PMU measurements are not available.