Effective Grounding of Wind Farm Collector （风电场收集器的有效接地）.pdfVIP

Wind Session Effective Grounding of Wind Farm Collector Circuits By BBen GGuthth, PP.EE. Doug Jones, P.E. What is transient overvoltage (TOV)? What is the cause of TOOV? How is TOV mitigated? Do all types of WTGs have problems with TOV? AAndd ddo allll miitiigatiion techhniiques workk ffor allll types?? How is TOV mitigating equipment specified? g g g y Must design an economical grounding system that: ◦ controls TOV to acceptable levels ◦ limits fault current while enabling secure ground fault pprotection Transient Overvoltages (TOV) can lead to surge arrester and other equipment failure GGroundiding ttransfformers or hihighh speedd groundiding switches usually provide adequate mitigation Different wind turbine types can mean different yp grounding methods TransformerTransformer 230 kV 69/92/115 MVA 34.5 kV 34.5 kV Main Bus 52CAP 52F1 52F2 52F3 52F4 Collector Collector Collector Collector DVAR 1 2 3 4 Typically 34.5kV Approximately 30MVA per circuit UndergroundUnderground cablingcabling forfor circuitscircuits tendtend toto bebe highlyhighly capacitive MOV typype surgge arrestors installed at each end of the cable system Pad mount or nacelle mounted generator step up t f (GSU) transformers (GSU) ◦ (35kV) solidly GndY primary – (1kV-480V) solidly GndY secondary ◦ (35kV)(35kV) DeltaDelta primaryprimary – (1kV(1kV-480V)480V) solidlysolidly GndYGndY secondarysecondary