高压直流电能计量系统计量误差研究

高压直流电能计量的准确性对直流系统电量结算和相关技术指标计算有直接影响。针对典型的高压直流电能计量系统,考虑系统中各装置准确级及误差的概率分布,结合工程实际使用的电能计量算法,建立了高压直流电能计量误差模型。分析表明在不同装置准确级组合情况下,直流电能计量系统的相对误差表现出与各环节误差分布的均值有关,直流侧总电能相对误差与换流单元正极和负极电能计量误差的均值有关。在换流站现场对直流电能表进行误差测试,得到被测直流电能表的计量误差情况。由于装置组合产生的整体误差会对系统损耗率较小的直流输电系统的损耗电能计量造成一定影响,因此应在计量装置满足准确级的基础上,适当增加周期性校准试验次数,并在调校过程中尽量降低装置的误差均值,从而提高高压直流电能计量的准确性。

Research on measurement error of high voltage direct current energy measurement system

As an important part of HVDC system, the accuracy of HVDC energy measurement has a direct impact on the power settlement and related technical index calculation. Aiming at the typical HVDC energy measurement system, considering the accuracy level of each device in the system and the probability distribution of the error, combined with the actual energy measurement algorithm used in the project, the error model of HVDC energy measurement is established. The simulation analysis shows that the relative error of DC power metering system is related to the mean value of error distribution of each link under the condition of different device accuracy level combination, and the relative error of total power on DC side is related to the mean value of positive and negative power metering error of converter unit. The error of DC energy meter is tested in the converter station, and the measurement error of DC energy meter is obtained. As the overall error caused by the combination of devices will have a certain impact on the loss energy measurement of the DC transmission system with a small loss rate of the system, it is necessary to increase the number of periodic calibration tests on the basis that the measurement device meets the accuracy level, and reduce the mean error of the device as much as possible in the calibration process, so as to improve the accuracy of the high-voltage DC energy measurement.