Comprehensive Error Of Distributed Substation Electric Energy On-line Calibration System

The measurement of electric energy is related to the settlement basis of various interests such as power production,transportation,and sales.The importance of it is self-evident.In order to measure accurately,the measurement system must be periodically verified.The digital substation in large-scale construction will become the mainstream,and its verification work is still indispensable,but the voltage,current combining unit and digital electric energy meter show a distributed special structure,and the traditional verification device is no longer suitable for this structure verification work.Therefore,the development of a supporting distributed verification system is of great significance to the development of the power industry.This project uses GPS timing technology and wireless network communication technology to develop a power pulse capture device and a host computer calibration platform.The platform receives the energy pulse and AC voltage and current sampling data transmitted by GPS,and uses the standard table method to verify the principle.The electric energy is accumulated by the accumulative method,and the on-line verification of the electric energy comprehensive error of the distributed substation is realized.The energy pulse capture device uses the cost-effective STM32F407ZGT6 as the control core,equipped with GPS module to decode and obtain the current time,making full use of the microprocessor's powerful interrupt processing mechanism and fast edge detection capability to capture the energy pulse output by the energy meter and mark the pulse.The time information is packaged and sent to the verification platform through the Ethernet module.The verification platform uses the powerful Delphi 10.2 as a development tool to make full use of the powerful computing power of the PC to realize online monitoring and power verification,as well as signal waveform review,historical verification query and result report printing.The verification platform sends a verification instruction,receives the sampling data and the energy pulse with the time stamp,and writes the data to the corresponding queue and saves the file to the file through the JSON format on the one hand,and adds window,FFT and interpolation to the extracted sample data for realize power monitoring on the other hand.At the same time,the time stamp in the data is fully utilized,and the sampling data corresponding to the same time is searched according to the pulse time in the queue for energy accumulation,and the phase shift interpolation fitting is performed for the additional phase shift existing in the system.The method corresponding to this time label can effectively overcome the impact of network transmission delay.Based on the research background and significance of the calibration device,combined with the development status at home and the actual needs of the project,the related power verification principle and algorithm,the software and hardware design of the energy pulse capture device and the software flow of each module of the verification platform and its debugging process are described in detail.The Fluke 6100 A standard source and RD-33 standard meter and DTZ733 type electric energy meter are used to test the accuracy and practicability,and the relevant data are recorded.The results show that all performance indicators are up to standard and can be used for energy metering verification of distributed substation.