| With the rapid increasing of wind turbines connecting into grid and achieving greatereconomic benefits, the overall security of the grid was under serious threat. From2009to2012,the wind bases of Jiuquan and Zhangbei have been constructed during this time. Accidents ofwind power chain trip-off were frequent have happened in our country. From2011to2012,205wind turbines trip-off faults. Faults caused varying level threat to the grid. Therefore, it is neededto take online early warning for wind turbines concatenate trip-off so as to increase the runningreliability of grid.This paper aims at intensively model of wind power base in our country, considering theinfluence to faults development caused by wind turbines trip-off in the faults scanning,establishing online early warning model for wind turbines trip-off. The main content are asfollows:(1) From the typical cases of the wind to take off the net, analysis and summarize reasons ofwind power trip-off. On this base, it establishes perfect the index about judging wind turbinestrip-off by means of the statistics analysis to Jiuquan wind power base LVRT trial.(2)Utilize electrical distance to sort and screen anticipate faults. Analysis and comparison ofdifferent calculation methods for electrical distance. Choose electric distant algorithm of fault setselection for online early warning for wind trip-off. Using electric distance screens faults thatmake wind power trip off, which improves the efficiency of online comp.utation(3)Aiming at wind turbines connecting to high voltage grid directly in the on-line data, it p.utforward virtual interface impedance and takes online equivalent simulation to wind power filedlow voltage side faults.(4)Online early warning model for wind trip-off is established. Calculate the trippingcapacity of wind turbines in the grid transient process, take wind turbines trip-off as disturbance tofault, analyszes the system stability question brought by cascading failure, provide correctdecision support to electrical power system dispatching staffs in order to prevent cascading failure. Both the correctness of the proposed method and the effectiveness of the proposed early warningmodel were verified by simulation results of Gansu grid. |
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