The application of advanced static VAr compensators to wind farms

Modern fixed speed wind turbines use induction generators which require a source of reactive power. Part of this requirement is usually supplied by local power factor correction capacitors (PFC) connected at the terminals of each turbine. The rest is supplied from the network, which can lead to low voltages and increased losses. Moreover, wind turbines are often installed at high wind speed sites which are remote, and have only weak electrical networks. In these cases, the effects of real and reactive power flows on the voltage quality are increased. Due to developments in power semiconductor devices and control techniques, the power ratings of convertor type VAr compensators have increased. Also, switching device costs are decreasing to a level where this type of equipment may provide a cost-effective method of improving the power quality of wind farms. In this paper some preliminary simulations of an advanced static VAr compensator (ASVC) to be commissioned on a wind farm are described.