Successful Mitigation of Week Roll Over Issue of Global Positioning System in Indian Power System - A Case Study

Power System utilizes precision timing for Grid monitoring & situational awareness to coordinate operation, integration and protection of Grid elements. Clocks needs to be precisely synchronized to common reference to enable integration of diverse data types and sources to assure that decentralized, parallelized analysis & control actions are effectively coordinated and implemented. Accurate time signals play vital role in analyzing source of fault by assessing the event logger & disturbance recorder data with time stamping. Not only operational & monitoring technologies viz. SCADA, PMUs are time dependent, commercial settlements like DSM, ABT, Billing, etc. also cannot be carried out with non-synchronized time signals. Accurate, consistent and uniformly aligned time is mandatory for mission critical applications such as closed loop wide area controls & real time operator decision support. Power system cannot afford even a single time glitch. Week Number Roll Over (WNRO) is one such issue which if not attended timely may result either in mal-operation or fetching misleading information. This paper discusses the issue of WNRO, its genesis, possible adverse impacts on power system operation and control. The paper also presents comprehensive strategy followed for successful mitigation of WNRO in Indian Power System.