The Analysis Of Commutation Failure In HVDC Transmission System Based On The New-Type Converter Transformer

For implementing the industrialization of the patent of invention and the patent of utility model:"Self-coupled and Harmonic Suppression Converter Transformer", and supported by the key science & technology project 05GK1002-1 of the Tenth Five Year Plan and 06GK1003-1 of the Eleventh Five Year Plan of Hunan Province. The key point is the analysis of commutation failure in HVDC transmission system based on the New-Type converter transformer. Commutation failure is one of the most common faults in HVDC transmission system. Compared with the traditional converter transformer, whether there are any advantages in improving commutation or not is a must for implementing the industrialization of the patent. This theoretical analytical system includes the following:(1)Firstly, analyzing all kinds of factors which can lead to commutation failure and sensitivity analysis based on CIGRE HVDC benchmark, to combine the analysis of San Guang-Echeng converter station commutation failure. At last, we get the general discipline of commutation failure in different running states in inverter side and some simple methods on commutation failure diagnosis.(2)Secondly, the research about the character of typical temporary-state-response and the methods for controlling its bad effects and give prominence to the New-Type converter transformer and its filter system in both steady state and transient state.(3)Through the analysis on influence of New-Type converter transformer and its filter system to commutation failure and mechanism of improving commutation, some measures are proposed to prevent the commutation failure.(4)Stimulating both the CIGRE benchmark and the HVDC model based on New-Type converter transformer and its filter system on PSCAD and Matlab which are useful tools in electric system. As a result, the simulation results can prove the advantages of New-Type converter transformer and its filter system in all the aspects of reactive power compensation,harmonic suppression and improving commutation failure.