Incremental PMU Placement Based on Depth of Unobservability

Abstract

This study presents the concept of incomplete observability for multi phasing of PMU locations in achieving redundant observability. This requires the study of optimal PMU placement problem for incomplete, complete and redundant observability. This paper uses BILP approach for solving optimal PMU placement problems. Each phase of PMU installation incorporates different observability concept. Initial phases involve incomplete observability while final phases take care of full and redundant observability. The network observability increases after each phase. During the initial phases, data of unobservable buses is estimated using conventional methods. This method has significance as it restricts the unobservability of bus only up to Depth-of-two unobservability. It ensures minimum distance between unobserved and observed buses during initial phases of PMU placement. The proposed approach is demonstrated on IEEE 30, 57 and NRIPG 246 bus system.