The Synchrophasor Report

In this issue of The Synchrophasor Report, we will provide a preview of the various synchrophasor-related topics that will be covered as part of the upcoming SEL Modern Solutions Power Systems Conference (MSPSC), taking place June 6–8, in Chicago, Illinois. This conference will focus on helping you solve power system challenges through a mix of presentations and interactive discussions with other utility engineers, executives, industry leaders, and SEL experts.

The relatively recent influx of DOE-sponsored synchrophasor projects has spurred the demand not only for synchrophasor technology, but more importantly, the know-how for commissioning such systems. This issue of The Synchrophasor Report covers some useful considerations for system commissioning as well as the services Schweitzer Engineering Laboratories Engineering Services (SEL ES) can provide for implementation assistance to customers in need.

In this edition of The Synchrophasor Report, we will look at applying a new synchrophasor visualization and analysis solution to improve power system performance and utilization. synchroWAVe^® Central Software allows you to use both real-time and archived data, providing additional information and new insights about your power system.

This issue of The Synchrophasor Report (TSR) discusses how to improve the availability of synchrophasor data to your end applications, including visualization, archiving, stability analysis, and state estimation. This issue also provides approaches to system configurations that will improve the probability of available data, which is important because synchrophasor systems are being used more frequently in mission-critical applications. The time, expense, and effort needed to increase the availability of data depend on how mission-critical the synchrophasor data are to your system.

In the April issue of The Synchrophasor Report, we discussed how synchrophasor measurements require a precise absolute time reference—one that provides better than 1 microsecond absolute accuracy. This time reference allows us to precisely measure voltage and current phasors across a wide area to better than 1 percent total vector error (TVE) as specified in the IEEE C37.118 Standard for Synchrophasors for Power Systems. Global Positioning System (GPS) satellite-synchronized clocks are the predominant means for providing precise time for phasor measurement unit (PMU) measurements. In this issue, we will examine ways to minimize the loss of the GPS time source.

This issue of The Synchrophasor Report (TSR) covers accurate timing—one of the key technologies that make synchronized phasor measurements possible. As you know, synchrophasor measurements require a precise, absolute time reference. The IEEE C37.118-2005 synchrophasor standard specifies that a clock be accurate to better than 1 microsecond. This is to ensure that the total vector error (TVE) measured by a phasor measurement unit (PMU) is less than 1 percent. There are several clocks that provide this level of accuracy, including rubidium and cesium atomic clocks; however, they are expensive and sensitive to temperature and vibration. An alternative is to implement highly accurate reference clocks, such as the SEL-2401, SEL-2404, or SEL-2407^®, which are satellite-assisted clocks that use the Global Positioning System (GPS) as their absolute reference.

In 2010, Schweitzer Engineering Laboratories, Inc. (SEL) introduced two new phasor data concentrators (PDCs)—the SEL-3373 Station Phasor Data Concentrator and SEL-5073 SYNCHROWAVE^® Phasor Data Concentrator Software. These PDCs have been very well-received by customers, many of who have offered several great ideas on how to make the PDCs even better. This issue of The Synchrophasor Report (TSR) discusses the first release of these enhancements, which are now included as standard features in the PDCs, and how they can be applied to your synchrophasor system.

This issue of The Synchrophasor Report discusses NERC PRC-002-2 Disturbance Monitoring and Reporting Requirements. In particular, we summarize the requirements of this standard and discuss the SEL solutions that address them.

Synchrophasor systems provide a new view of power system operation by providing real-time, accurate, time-aligned measurements from across the system. The most common use of these systems is for visualization and archiving of system data, with some customers using these systems for control and protection. Most synchrophasor systems installed today are not considered critical assets; however, SEL believes that security for synchrophasor systems should be treated similarly to other systems used in your power network.

SEL’s mission is to make electric power safer, more reliable, and more economical. One of the latest additions to SEL’s product line does exactly that. By building on the experience gained from existing SEL phasor data concentrators (PDCs) and integrating feedback from our customers, SEL has created the new SEL-5073 synchroWAVe^® Phasor Data Concentrator (PDC) Software. The first of two new PDCs that will be available from SEL this year, this new software PDC simplifies the configuration and use of synchrophasor information. A hardware PDC, the SEL-3373 Station PDC, will debut in September.

The SEL Distributed Coherent Systems group recently participated in a witness evaluation test as part of the U.S. Department of Energy (DOE) Solar Energy Grid Integration System (SEGIS) program. PV Powered, Inc., Northern Plains Power Technologies, Senus, Portland General Electric, and SEL partnered to demonstrate a smart islanding technique that uses synchrophasors in the Oregon Solar Highway project PV generation site. This issue provides an overview of the system configuration and the witness evaluation test.

Many customers are in the process of obtaining synchrophasor measurements from their power systems by installing phasor measurement units (PMUs). One concern with installing this new technology is how to get real-time synchrophasor information to a central location. This is of special concern for substations that are located at remote sites and typically have limited communications bandwidth. This article will review the communications standard defined for sending synchrophasor information and discuss different approaches for getting the right communications architecture for your needs.

A minimal synchrophasor system consists of phasor measurement units (PMUs) and integration of the data collected into centralized operator displays. This approach, while providing an immediate benefit over existing SCADA systems, misses many opportunities for additional power system improvements.

A more capable system includes a substation phasor data concentrator (PDC) with archiving capability or a distributed control processor such as a synchrophasor vector processor (SVP). These solutions greatly expand synchrophasor system capabilities.

As the popularity of wind power, characterized by fluctuating power generation and remote locales, continues to grow, operators are looking for ways to address unique challenges. Synchrophasor data are a great solution to the problems posed by wind power generation because you can get the data you need without having to travel to the remote locations where wind farms are often sited. This saves travel time and costs, while allowing operators to manage their operations efficiently and effectively. Allowing improved power system reliability, real-time control, and reductions in cost and complexity, synchrophasors are the tools of choice when making decisions that affect the interconnected power system.

Utilities worldwide are rapidly deploying synchrophasors. Synchrophasors are no longer merely a research technology; rather, they are becoming preferred real-time power system solutions. This issue discusses ways to use the SEL-3378 Synchrophasor Vector Processor to detect an islanding condition and to create an adaptive load-shedding scheme.

Synchrophasors provide a unique opportunity to archive and view data across a wide geographic area. When measuring devices are connected to a precise, global time source, such as GPS, time stamps provide a means to align the data for analysis. Although time-synchronized phasors are the more well-known application, any data can be globally time-stamped. Today’s relays, such as the SEL-3XX family and SEL-4XX family, provide time-stamped information for both synchrophasors and event reports. This issue explains the mechanics of acquiring wide-area information.

Engineers around the world are beginning to regard synchrophasors as one of the most important applications of smart grid technology. Wide-area control, disturbance recording, and system visualization are some of the many applications improved with synchrophasors. This issue of The Synchrophasor Report discusses ways of bringing wide-area measurements into a SCADA system with either Modbus^® or DNP3 protocols, or with a dedicated communications processor.