Study on Transient Voltage Stability of Wind Farm Incorporated System with Reactive Power Compensation Device

With the rapid development of wind power generation technology in recent years, it has caused a number of new problems when large scale wind electricity incorporates into power system. One of the most serious problems is that the randomness and volatility of wind generation output or grid fault may lead wind farm to quit operation totally, then power balance of the system is broken and the transient voltage stability of the system is seriously threatened. Therefore, it's quite necessary to study transient voltage stability of the power system with wind power generation incorporated. Above all, the mechanism of transient voltage instability is explained. A model of an actual electrical network, with large-scale incorporation wind electricity 50% to the total installed, is built in BPA. Based on electrical network model, the simulation design and analysis are carried on in detailed. As wind speed fluctuation and short circuit fault are two common kinds of disturbances in wind power integrated system, we study the influences on the transient voltage stability of the system in both cases. On this basis, as SVC and STATCOM are two dynamic reactive compensation devices, their abilities of system voltage supporting are analyzed by comparing the voltage wave forms in cases of SVC or STATCOM being configured or not. Results show that, it can cause adverse impact in both cases of wind speed fluctuation and short circuit fault. When wind speed suddenly increases the voltage of the system decreases. While with SVC or STATCOM configured in the power system, decreasing extent of system voltage is reduced in case of wind speed suddenly changing. The results also show that the voltage supporting function is more obvious when STATCOM is configured than SVC. As for cases of single-phase grounding fault and three-phase grounding fault, when the fault occurs the voltage of the system decreases. But when SVC or STATCOM is configured in the power system, decreasing extent of system voltage is reduces. It can be observed that the dynamic reactive power compensation devices STATCOM has a greater contribution on system voltage supporting, it is more effective in the field of reactive power compensation than SVC.