A novel coast-down no-load characteristic test and curve conversion method for large-scale synchronous condenser

摘要

Large-scale synchronous condensers (LSCs) are synchronous motors that have no prime movers and that operate in a continuous no-load condition. They will soon be widely used as the main dynamic reactive power compensation equipment for transmission systems in ultra-high voltage direct current (UHVDC) transmission projects across China. As the standard no-load characteristic test procedure is not applicable when the LSCs are installed at UHVDC converter stations, this paper presents a novel coast-down no-load characteristic test and curve conversion method that has been successfully applied to a 300 Mvar LSC. For the proposed test, the LSC is set to run a coast-down process and its excitation current is incrementally increased. In order to get an accurate no-load characteristic curve, a series of data processing methods, including frequency conversion, wavelet denoising and a hybrid optimization algorithm for saturation correction are used. To validate the proposed method, the test results were compared to the no-load characteristic curve obtained by the standard method.