Study On Electrical Parameters Measurement Error In Electrical Energy Metering

Electricity is the main energy of national economy and people's lives.The extent of its application is the main symbol to measure a country's development level and comprehensive national strength.The character of energy production is that power plant generates electricity,electricity sector supplies electricity and consumer uses electricity.They form a system and complete incessantly.Energy measurement is the basis for settlement.So the energy measurement accuracy affects the vital interests of three parties. With the development of power industry, a large number of power electronic devices and nonlinear devices are widely used in the electrical equipment in all walks of life. A large number of harmonics produced by these loads are injected into the power system,affect the accuracy of electrical parameter measurement in the energy measurement.By studying the electrical parameter measurement error in electrical power measurement.The main tasks of the thesis are presented as follows:â‘ The paper demonstrates the importance of energy measurement and electrical parameter measurement from the development status of the domestic and international energy measurement technology, existing problems and developing trend, demonstrates the importance of improving the accuracy of energy measurement and electrical parameters measurement;â‘¡According to the principle of energy measurement devices, from the point of integrated error view, study the transformer synthesis error, the second drop synthetic error and A/D quantization error. Transformer synthesis error formula is derived. The electrical parameter relative error formula caused by A/D quantization error is deduced from the A/D quantization error. When the number of sampling points is greater than 600, the measurement error caused by quantization error is less than one tenth of the A/D conversion quantization error;â‘¢In the time domain and frequency domain,when the the signal is measured by using the entire period measurement, the sampling signal contains all the information of original analog signal, there is no truncation error in time domain and leakage error in frequency domain.There is no measurement error when the signal is measured by using the synchronous sampling algorithm.The error formula to measure signal is derived by using non-synchronous sampling algorithm, non-synchronous sampling is mainly caused by fluctuations of the measured signal frequency, the greater the frequency fluctuations, the greater the error. In the measured frequency fluctuations, the sampling start angle and the sampling points are also factors that influent the error. For the active power measurement, the size of power factor also affects the accuracy of power measurement.â‘£The ratio error and angle error correction formula are derived by studying the transformer ratio error and angle error, using correction formula to correct the electrical parameters,which can improve the accuracy of electrical parameters measurement. Fluctuation of grid frequency is difficult to achieve synchronous sampling, but there exists error when use non-synchronous sampling, the weighted algorithm is proposed to eliminate non-synchronous sampling error; for signals that contain harmonic, contrast the characteristic of different window function, in view of the point that Nuttal window function has a good side lobe performance, introduce Nuttal window function spectrum weighted correction algorithm to improve the accuracy of electrical parameters measurement.