配电网供电能力曲线的规律与机理

Law and Mechanism of Supply Capability Curve for Distribution Networks

配电网的供电能力不仅是最大供电能力(total supply capability,TSC)的一个点,而是一条曲线,即供电能力(boundary supply capability,BSC)曲线。实际配电网BSC曲线的大多数点都相对TSC有所下降。该文初步揭示了BSC曲线下降规律与机理。首先,观察N供一备、分段联络等典型接线,发现了BSC曲线的下降规律。其次,揭示BSC曲线下降是备用机理和分配机理共同作用的结果:备用机理指馈线间的"一对多"备用关系会造成BSC值下降;分配机理指N-1后一回馈线的负荷在多回馈线中分配后转移,补偿了BSC的下降。然后,进一步发现了备用/分配机理对BSC作用的定量计算公式。最后,用IEEE-RTBS-BUS4扩展算例验证了该文机理及公式的正确性。

The supply capability of distribution network is not only a point at total supply capability(TSC), but also a curve, that is, boundary supply capability(BSC) curve. The values of most points in the BSC curve decrease compared to TSC. This paper revealed the law and mechanism of the decline of BSC curve. Firstly, the qualitative and quantitative laws of BSC curve decline were discovered through the observation of the BSC curves of typical connection modes,including N-supply-one-backup mode, multiple-section-and-tie mode, etc. Secondly, it revealed that the decline of BSC curve is the common result of the backup mechanism and the distribution mechanism. The backup mechanism means that the‘one-to-many’ backup relationship among feeders will cause the drop of BSC;the distribution mechanism means that the loads of N?1 feeder are distributed to connected feeders, which will compensate for BSC decline. Thirdly, quantitative formulas of the backup/distribution mechanism for BSC were further discovered. Finally, an expanded IEEE-RTBS-BUS4 case was used to verify the proposed mechanism and formulas.