三相不平衡扰动源的定位

Disturbance source locating for three-phase imbalance

通过仿真算例研究了在正常运行工况下导致公共耦合点电压产生不平衡现象的主要因素。以不平衡负序分量为例,提出将公共耦合点上游侧的不平衡源等效为戴维南等值电路,建立了判定公共耦合点不平衡扰动源所处位置的数学分析模型,进而提出了划分不平衡责任的指标。从公共耦合点的电压和电流数据中,选出在负荷侧波动而在系统侧基本保持恒定的数据用于估算上游侧戴维南等值电路参数,该方法不需同步采样数据、不受系统频率变化的影响。仿真算例验证了所提方法的有效性和精确度。

The main factors causing the PCC（Point of Common Coupling） voltage imbalance in normal operating conditions are studied by case simulation. With the negative-sequence component imbalance as an example,the imbalance source at the upstream side of PCC is considered as a Thevenin equivalent circuit to establish a mathematical analysis model for locating the imbalance source at the upstream side of PCC.An index is proposed to assign the imbalance responsibility. The data of PCC voltage and current,which are fluctuated at the load side while kept constant at the system side,are selected to estimate the parameters of the Thevenin equivalent circuit at the upstream side. Immune to the system frequency variation,the proposed method does not need the synchronized sampling data. Simulative study verifies its validity and accuracy.