Distributed Algorithms for Wide-Area Monitoring of Power Systems

摘要

Following the Northeast blackout of 2003, the Wide-Area Measurement System (WAMS) technology using Phasor Measurement Units (PMUs) has largely matured for the North American grid. However, as the number of PMUs scales up into the thousands in the next few years, Independent System Operators (ISO) and utility companies are struggling to understand how the resulting gigantic volumes of real-time data can be efficiently harvested, processed, and utilized to solve wide-area monitoring and control problems for any realistic power system interconnection. It is rather intuitive that the current state-of-the-art centralized communication and information processing architecture of WAMS will no longer be sustainable under such a data explosion, and a completely distributed cyber-physical architecture will need to be developed. Research is being carried out currently to address this architectural problem by developing new communication and computing protocols for WAMS through NASPInet and Phasor Gateway to facilitate PMU data communication between multiple utilities and control centers. However, almost no attention has yet been paid to perhaps the most critical consequence of this envisioned distributed architecture - namely distributed algorithms. Partly due to a lack of a cyber-physical research infrastructure and partly due to the priorities set forth by PMU installations, researchers have not yet delved deeply into investigating how the currently used centralized algorithms for wide-area monitoring and control can be translated into a distributed computing framework once the aforementioned decentralized WAMS architecture is realized in the coming years. In this article we present an overview on how one may develop a distributed algorithmic framework for critical WAMS applications that integrates power system computation, distributed computing and advanced networking technologies. Our approach is to consider the three most critical research problems in WAMS-based power system operations, and divide their algorithmic implementation into hierarchical levels of intra-regional and inter-regional computational clusters, connected to each other via a resilient communication network. These three applications are, namely - 1. Wide-area oscillation detection and modal analysis, 2. PMU-based transient stability assessment, and 3. Voltage stability monitoring. We will describe ideas on how the algorithmic implementation of these three WAMS monitoring applications will need to be redesigned as the PMU-PDC architecture goes from centralized to distributed. The proposed algorithmic framework will study how multitudes of geographically dispersed PMUs and PDCs can communicate with each other co-operatively for successful execution of critical transmission system operations, and how the various binding factors in the distributed network can pose bottlenecks for their performance. The results will provide valuable insights and guidance in deploying future PMU and PDC infrastructure, not only for power systems but for any generic cyber-physical sensor network.