TThe inTeresT in phasor measuremenT Technology has reached a peak in recent years, as the need for the best estimate of the power system's state is recognized to be a crucial element in improving its performance and its resilience in the face of catastrophic failures. in most countries installing the phasor measurement units (pmus) and getting to know the pmu system behavior through continuous observations of system events has been the first step. all installations are reaching for a hierarchical wide-area measurement system (Wams) so that the measurements obtained from various substations on the system can be collected at central locations from which various monitoring, protection, and control applications can be developed. in this article, experts from several countries summarize their Wams-related activities in some detail. it is of course not possible to claim that this is a complete list of countries pursuing this technology. To the best of our knowledge similar activities are also progressing in south africa, Taiwan, Japan, and several other countries. however, the contributions here provide an account of the most advanced stages in Wams development in major world economies.-A.G. Phadke The Brazilian national interconnect power system (sin) is characterized with a dominant hydroelectric power generation and long-distance power transfers from generation parks to load centers (Figure 1). studies for phasor measurement applications in Brazil were started in the early 1990s by the study committee of the interconnected operation coordination group (gcoi), prior to the deregulation of the Brazil energy sector. difficulties faced by the Brazilian economy during that decade and the restructuring process of the electric energy sector delayed the project.

Recent power system blackouts around the world have driven attention to the need of Wide Area Measurement, Protection and Control (WAMPAC) systems. Currently, the Brazilian electric power industry is making an effort, lead by independent system operator ONS, to implement a large-scale wide-area measurement system utilizing the synchronized phasor measurement technology. The system will be utilized to realize many off-line and real-time operation applications for improving the reliability and economical operations of the National Interconnected Power System (NIPS). The novelty of the technology and the task to implement such a system in a deregulated environment present some special challenges to the project and ONS. This paper describes the overall approach that the Brazilian power industry and ONS had adopted in implementing this system. The approach aims to address several main aspects of the project that are critical for a successful implementation of the system, such as the regulatory framework, under which the system is to be deployed, deployment planning, and overall system performance assurance measures. The project has successfully completed the system architecture design and corresponding system components specifications. ONS is currently in the process to hire a qualified test entity to perform the PMU homologation testing and calibration.Index Terms--PMU performance test and calibration, Synchrophasor, Wide-area measurement.

No abstract

The invention of the Phasor Measurement Unit (PMU) in mid 1980's enabled the synchronized measurements of voltages and currents in real time that has become the foundation of today's wide-area measurement, protection, and control (WAMPAC) systems. The trend in recent years is the steady increase of PMU installations worldwide for various applications, such as those targeted for State Estimation enhancement. Several algorithms/methods for optimal PMU placement have been introduced to minimize the system cost while still achieving the full observability of a power system with a minimum number of phasor measurements. These algorithms perform an optimization process by considering all system buses. In real systems, for practical reasons, some buses may be selected for mandatory PMU installations and some others can be selected as not desirable for PMU installations. In other words, a group of buses may be identified for the optimal placement. In this paper, a virtual data elimination preprocessing method and a matrix reduction algorithm are introduced for reducing the scale of a placement study. By identifying those buses with "known status", the method could significantly reduce the computation efforts. The methodology has been applied to four IEEE systems and the Brazilian National Interconnected Power System. The sizes of these systems before and after the reduction are tabulated to show the effectiveness of this method in reducing the computational effort. To prove the performance guarantee for the proposed algorithm, Lagrangian Relaxation has been applied to calculate the low bound of the minimum number of PMUs necessary for full observability. The results are shown in the simulation section.