Research On Error Analysis And Calibration Method Of Multi-bay Digital Energy Metering System

A substation bay is a group of closely connected electrical units in a substation that jointly implement certain functions.With the rapid development of digital substations based on the IEC 61850 communication protocol,multi-bay energy metering is also facing a new issue of digitization.There is a big difference between multi-bay digital energy metering and traditional multi-bay energy metering and single-interval digital metering.Due to the unclear error composition and unquantified influencing factors,the multi-bay digital energy meter has the problems of inaccurate energy calculation and unstable operating state during the test process;on the other hand,due to the immature verification specifications and the lack of verification equipment standards limit the promotion and application of multi-bay digital measurement systems.In this paper,the influencing factors of multi-bay digital measurement error were first studied.The error analysis of multi-bsy measurement is carried out from the three aspects of frame loss error,delay impact error and quantization error.The research results show that the measurement error caused by packet loss and transmission delay is large and cannot be ignored;while the quantization error can be ignored in multi-bay digital measurement.In order to decrease the measurement error caused by packet loss,the compensation methods based on the combination of time dimension and space-time dimension were studied.First,the interpolation compensation method based on the time dimension is used to compensate for the message loss error.The compensation methods of Lagrangian,cubic spline and Newton interpolation methods are studied separately.The simulation shows that there is a certain compensation effect,but there is compensation under certain conditions.The problem of insufficient precision.Aiming at the limitation of the compensation accuracy of the conventional interpolation method,the loss-of-phase compensation method of the inter-phase relationship combined with the space-time dimension is studied.The simulation shows that it has better compensation effect under certain conditions.Aiming at the error caused by time delay between multi-bay measurement voltage / current sampling values,the time delay error compensation method based on improved phase shifter is studied,and the frequency measurement method of Newton third-order interpolation and dichotomy is proposed to improve the phase shifter.The accuracy of delay compensation.In view of the immaturity of multi-bay digital measurement verification specifications and the lack of standards for verification equipment,this paper adds two items of multi-bay frame loss error verification and delay error verification on the basis of the single interval measurement verification method,and develop Multi-bay digital output power source is used as the verification source.Based on LabVIEW virtual instrument and SQL Server database technology,a multi-bay digital measurement and calibration system software platform was developed.Based on the developed software and hardware platform,the test was carried out and the test results were analyzed.The test proved that the developed device meets the accuracy requirements for the detection of the 0.2-level multi-bay digital measurement system.