农村配电网中多谐波源谐波叠加算法的研究

Algorithm for calculating harmonics superposition of multi-harmonic sources in rural power grid

大量的非线性负荷应用在农村配电网中,在农网中出现了多谐波源的现象。当多谐波源产生的谐波电流相角不确定时,谐波叠加计算问题变得异常复杂。针对这一问题,论文在一定假设条件下,提出了一种研究多谐波源谐波电流叠加的方法,利用概率统计学中的大数定理和中心极限定理,推导出了谐波叠加的计算公式。当谐波源数量足够多时,期望值可表示谐波电流的幅值,从而为合理的治理谐波提供依据,以避免治理时的资源浪费。仿真结果表明应用此方法来计算多谐波源的谐波电流幅值问题,可以得到满意的结果;多谐波源叠加时谐波电流相互抵消明显。

There appeares the multi-harmonic source phenomenon in the rural distribution network because many nonlinear loads are put into operation. The computation of harmonics superposition becomes more complicated when harmonic currents are caused by multi-harmonic sources at random phase angel. To solve this problem, an algorithm to analyze and research the multi-harmonic sources was proposed based on certain assumptions, and the calculation formulae of harmonic superposition were deduced based on Big Number Theorem and Central Limit Theorem of probability statistics. When harmonic sources are enough, the expectation can denote the harmonic current value which can provide rational data for harmonic suppression and avoid a waste of resource. The simulation results show that using the method to compute the values of harmonic current caused by multi-harmonic sources, a satisfactory result could be obtained and the harmonic currents by multi-harmonic sources could be counteracted one another.