AMSC’s STATCOM Replaces SVC at Ergon Energy A Case Study by AMSC • September 2012 The Background Ergon Energy is an Australian electricity distributor, retailer and generator, servicing around 680,000 customers across an operating area of over one million square kilometers – 97% of the state of Queensland. Despite the presence of a static VAR compensator (SVC) at one of the area substations, this utility had begun experiencing voltage stability problems in its network around St. George, which is situated 500 kilometers inland of Brisbane on the Balonne River in southern Queensland. By utilizing AMSC’s D-VAR ® system, Ergon was able to resolve these instability issues while also retiring the SVC system. The Problem Ergon Energy was utilizing an aged SVC that was experiencing occasional outages and failures at its St. George substation, which is located in a remote area and is served by a single, 194 kilometer subtransmission feeder operating at 66 kilovolts. This SVC system was exposing the surrounding grid to significant voltage fluctuations caused in part by switching of large commercial farming, cotton gin and pump loads. In order to continue managing power quality in the surrounding area, the SVC system required replacement with a solution that was able to normalize system voltages to acceptable levels at all times and was also able to be expanded to meet future VAR requirements. AMSC’s Analysis AMSC’s Network Planning and Applications Group performed a series of studies for Ergon Energy to determine the solution’s optimal/desired: • Dynamic performance • Harmonic performance • Grid impact These studies determined that a hybrid solution consisting of STATCOMs and capacitors would be the optimal approach to meet Ergon Energy’s cost and performance perspective requirements. Classified as a Flexible AC Transmission Systems (FACTS) device, AMSC’s D-VAR STATCOM utilizes the company’s proprietary and advanced control and monitoring algorithms that detect and instantaneously compensate for voltage disturbances by injecting leading or lagging reactive power (VARs) precisely when and where it is needed. The reactive power is generated by AMSC’s proprietary four-quadrant IGBT inverters that are capable of fully injecting capacitive or inductive VARs in one line cycle. The system’s full dynamic capability of 2.67 times its rated output can be provided for up to two seconds.