ABB Review Special Report - ABB - ABB Group

8SVC performance. Results of a phase-to-ground fault in the Auas substation1.211pu1.0pu0pu00.80.64.5 5.0 5.5 6.0 6.5-1-2BrefDI4.5 5.0 5.5 6.0 6.5-1-2BrefADD4.5 5.0 5.5 6.0 6.5t (s)Voltage response, 400 kV SVC controller output Impact of resonance controllerThis extreme test was also performedin the field. Comparison of the simulationresults and the system performancetestshowsvery goodagreementand underlinesthe improvementcapabilityAs a result of installing the ABBSVC, the resonance problems thathad previously plagued theNamibian grid are a thing of thepast.of the new resonance controller underresonance conditions.Staged fault testAfter the Auas substation had beencommissioned, a phase-to-ground faultwas used to test various SVC controlfunctions and the interconnection protectionscheme. The performance ofthe SVC is shown in 8 . As the resultsshow, theSVC controlsthevoltageand theresonancecontrollerforces theSVC tobecome fully inductive in resonanceconditions. The fault is initiated att = 4.9 s and is cleared by openingthe faulty phase in the Auas-Kokerboomline. A single-phase auto-reclosureis initiated after 1.2 s, starting withthe breaker on the Kokerboom side.The overvoltage at Auas is reduced to1.14 pu.Easier cross-border power sharingAs a result of installing the ABB SVC,the resonance problems that had previouslyplagued the Namibian grid area thing of the past. Southern Africa’sstate energy sectors can now be moreeasily integrated and power more easilyshared. And the growing demand forpower – the motor driving the region’seconomic ambitions – can be moreeasily met.Rolf GrünbaumMikael HalonenStaffan RudinABB Power TechnologiesSE-721 64 VästeråsSwedenFax: +46 21 18 31 43rolf.grunbaum@se.abb.comReferences[1] R. Grünbaum, M. Noroozian, B. Thorvaldsson: FACTS – powerful systems for flexible power transmission. ABB Review, 5/1999.24Special ReportABB Review