A Method of Improving the Accuracy of Online Calibration of AC Sampling Device

Abstract

The invention discloses a method for improving the on-line calibration accuracy of an AC sampling device. The method comprises the steps of (1) connecting AC voltage and AC current into an alternating current sampling calibration device, (2) carrying out rapid sampling on the connected AC voltage and AC current and storing obtained digital signal quantity in a stack mode, (3) using digital signal processing technology, carrying out one time of computing processing per 1 / 2T, carrying out comparison with the measurement value of a front 1 / 2T, and judging whether electricity which flows in jumps or not in the time 1 / 2T, (4) capturing the stable input of the AC voltage and current through the method, if the electricity does not jump, judging that the current is stable, carrying out weighted average processing on measuring values of repeated DSP calculation, and obtaining a final measuring value, (5) comparing the final measuring value with the measuring value of the AC sampling device, and calculating the sampling error of the AC sampling device. According to the method, the working efficiency and safety of working are raised, and the test precision is high.

Description

[0001] Technical field: [0002] The invention relates to a method for online verification of an RTU (REMOTE TERMINAL UNIT, remote terminal device) AC sampling device, in particular to a method for improving the accuracy of the online verification of RTU AC sampling. [0003] Background technique: [0004] According to the requirements of the "National Grid AC Sampling Device Calibration Specification" promulgated by the State Grid Corporation of China in 2005, the verification of the installed site of the AC sampling measurement device is divided into two methods: line calibration and offline calibration. [0005] The off-line calibration technology is very mature. Since the three-phase AC voltage and current are input to the AC sampling device through the high-precision and high-stability three-phase standard, the AC sampling device and its calibration device test stable voltage and current. The test value will not jump, so it can meet the higher sampling accuracy requirement...

AI Technical Summary

Problems solved by technology

However, during online calibration, the AC sampling device and its calibration device test the AC volume on the power line. Due to the high discreteness of parameters such as voltage, current, power, and frequency on the power line, the sampling value of the AC sampling device is constantly changing. The measurement of the tester and the AC sampling device is not synchronized, and the sampling value of the AC sampling device is uploaded through CDT101, CDT103 or CDT104 telemetry, and a certain communication delay is required, resulting in a large difference in the number of samples between the two. Therefore, it is difficult to accurately verify the sampling accuracy of the AC sampling device

At present, the traditional online AC sampling test method is adopted, and the accuracy is 0.5, which cannot meet the technical requirements of 0.2, resulting in insufficient test accuracy.

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