交流滤波电容器不平衡保护的原理和计算

Principle and Calculation on Unbalance Protection for AC Filter Capacitor Bank

论文对高压三相交流滤波电容器不平衡保护的计算进行了大量的理论分析,指出:高压交流滤波电容器较之并联补偿电容器的不平衡保护计算要复杂得多,既有基波分量的计算,还有谐波分量的计算。基波分量的计算与并联补偿电容器的计算相类似。论文重点分析了谐波分量的计算问题,给出了谐波源谐波电流在系统和三相不对称电容电路间分流计算的三相电路模型。并在此模型的基础上,推导出电容器的谐波电流和谐波电压,以及不平衡保护谐波分量计算需要的各种公式。总的不平衡电流或电压应为其各分量的平方和的平方根。论文为滤波电容器不平衡保护计算提供了理论依据和适用的计算公式。

In this paper, a great deal of theoretical analyses on the calculation of unbalance protection for high voltage three-phase AC filter capacitor are carried out and it is pointed that： Unbalance pro- tection calculation for high voltage AC filter capacitor is more complicated than that for shunt com- pensation capacitor, not only in the calculation of fundamental component, but also in the calcula- tion of harmonic component. The calculation of fundamental component is similar to that of shunt compensation capacitor. The calculation of harmonic component is selectively analyzed. Three-phase circuit model for shunt calculation of harmonic current of harmonic source in the system and asym- metrical capacitance circuit of three-phase is given, and, on the basis of such model, the harmonic current and voltage of the capacitor as well as various formulas for calculating unbalance protection harmonic component are derivated. The total unbalance current or voltage should be equal to the square root of sum of square of its respective component. In this paper, the theoretical base and ap- plicable calculation formula for unbalance protection calculation of filter capacitor are provided.