电力参数交流采样测量的误差分析

Error Analysis of Power Parameter in Alternating Sampling Measurement

对电力参数交流同步采样有效值测量的典型算法梯形法的截断误差进行了分析,给出了与采样点的关系:与采样点数N的平方成反比,N>26,有近0.5级准确度;N>40,有0.2级准确度;N>57,有0.1级准确度。对舍入误差结合A/D转换器、CPU以及指令的实际使用情况,做了在8位、16位单、双精度以及定点、浮点情况下的准确界定。采用8位器件单精度运算时要考虑溢出问题,其他情况其误差可忽略不记。

The truncated error of trapezoid method, a classical algorithm, is analyzed for sampling power parameter AC in-phase virtual value and the relationship between the error and the amount of sampling points is offered: the truncated error is square inverse ratio with the amount of sampling points. When the amount of sampling points is over 26(N>26), the accuracy is 0. 5; the amount of sampling points over 40(N>40), the accuracy 0. 2; the amount of sampling points over 57(N>57), the accuracy 0.1. Considered A/D converter and CPU and instruction, rounding error in a byte and double byte of fix-point and floating-point are accurately bound. Applied the 8bit elements and odd precision, the overflow should be considered. The rounding error can be ignored for the rest.