基于相序分解和量测值的三相不平衡度计算方法
Three-Phase Unbalance Calculation Method Based on Phase Sequence Decomposition and Measured Value

国标定义的三相不平衡度需要测得三相向量的幅值和相位，且计算过程中需要进行向量运算，运算较为繁琐，而在实际工程应用中，三相向量的相位不易测得，也使得基于相序分解的计算方法不适用；一些国际组织或团体为了简化计算，采用三相向量的量测值进行计算，此类方法虽然舍去了复杂的向量运算，但也同时造成计算结果与国标定义的相比误差较大。基于此，本文提出了以三相零序分量和负序分量量测值的平方和与三相正序分量量测值的平方之比来定义三相不平衡度，该方法只需要三相向量的幅值即可计算，且经过算例分析，该方法与较接近国标定义的计算结果。
The three-phase unbalance degree defined by the national standard needs to measure the ampli-tude and phase of the three-phase vector, and the vector operation is needed in the calculation process, which is more complicated. In practical engineering applications, the phase of the three-phase vector is not easy to be measured, which makes the calculation method based on phase sequence decomposition not applicable. In order to simplify the calculation, some international or-ganizations or groups use the measurement value of three-phase vector for calculation. Although this kind of method eliminates the complex vector operation, it also causes a large error compared with the calculation result defined by the national standard. Based on this, this paper proposes to define the three-phase unbalance degree by the square ratio of the square sum of the measured values of the three-phase zero-sequence component and the negative sequence component to the measured values of the three-phase positive sequence component. This method only needs the am-plitude of the three-phase vector to calculate, and through the calculation example analysis, this method is close to the calculation result of the national standard definition.