Observability algorithm for power network based on topological segmentation

LIU Ying1, XIAO Tannan2, ZOU Yu1, XIA Yanhui1, Tong Weilin2, WANG Jianquan2

(1.Nanjing SAC Power Grid Automation Co.Ltd., Nanjing 211153, China;
2.College of Electric Engineering, Zhejiang University, Hangzhou 310027, China)

Abstract: Aiming at power network observability problem, the measurement network modeling, network topological observability analysis theory, and the influence scope of unobservable nodes was analyzed to derive a new observability analysis algorithm, which was tested on a 42node system, based on topological segmentation. The power network with measurement was modeled as a measurement oneline graph. Using breadth first bidirectional search, observability of subgraphs with line flow measurement was analyzed after tearing the original oneline graph apart at node without injection measurement. The influence of unobservable part in unobservable subgraph was then determined to obtain all observable islands. Considering known observable islands, observability of subgraphs which only had injection measurement was analyzed and observable islands in them were got. Finally all observable islands sharing same nodes without injection measurement were combined. The algorithm can get all the observable islands while observability analysis. The results indicate that the algorithm is correct, effective and maintaining the rapidity of topological method.

Key words: network observability; measurement oneline graph; topological segmentation; observable islands