MULTISTAGE OPTIMAL PMU PLACEMENT USING MULTI CRITERIA DECISION MAKING APPROACH

Abstract

Phasor Measurement Units (PMU) utilise digitised voltage and current phasors along with - synchronised time stamping for Wide Area Monitoring Protection and Control (WAMPC) of an inter-connected modern power system. PMU, centralised data storage, management, analysis and data communication network forms an important element of WAMPC. Owing to high cost of PMUs, communication facility, GPS and its installation, only an optimal placement of the PMU is envisaged in any large practical power system. This necessitates optimal PM1J placement fulfilling topological observability thus making complete power system observable. Optimal PMU placement for complete observability with and without zero injection measurement has been worked out using Binary Integer Linear Programming in MATLAB. k PMU deployment demands large investment comprising of cost of PMUs, its installation requirements and support infrastructure. These requirements pose physical and financial constraints on PMU installation in a large power system, where big quantum of PMUs would be installed for making it observable. A multi stage installation program assists in achieving phased PMU installation and effectively utilise benefits even during installation process. The main contribution of this work is to highlight multistage PMU installation program based on revised Analytical 1-licrarchy Process (Al-IP), which maximizes power system observability without increasing the total number of optimal PMUs in any system.AHP technique based on Multi Criteria Decision Making (MCDM) covers both qualitative and quantitative aspects of decision making. The technique includes criteria in relevance to decision making objective of phased PMU installation. It formalises criteria weight assignment and decision making process into mathematical science. Generating nodes and reactive power sources are important entity in power system operation and control. Their location and characteristics impact voltage stability of the system. Generator Observability Criteria (GOC) has been especially included in this work in MCDM process to incorporate better generator observability when implementing multistage PMU installation. Three more criteria, PMUs Distribution Criteria (PDC), Tie Line Observability Criteria (TOC) and Bus Observability Criteria (BOC) have also been included for decision making in multistage PMU installation in power systems. The approach has been tested on standard IEEE 14-bus system and IEEE 30-bus system. The technique developed has been applied to propose multistage PMU installation in North India Electric Region (NlER) with and without zero injections for complete observability. III