Research On Security And Stability Control Of Large-scale Wind Power Delivery System

The wind power resources of China are mainly distributed in the north, northeast, northwest areas. The wind power bases in these areas are mostly located in remote areas. The local electricity loads of these areas are low so that the absorptive capacity of wind power is limited. Therefore, large-scale wind power must be sent to other areas through the outer to consume. In recent years, the increasing penetration of large-scale wind power bases, not only brings a wealth of economic benefits, but also makes an impact on the safety and stability of the power system. It has resulted in the need for consideration of the impact brought by wind power in the power system security and stability control under severe failure to develop appropriate control measures. In this paper, by studying wind power delivery and stability control relevant literature, two typical wind power delivery systems, which are Wind&Fire bundled delivery system and wind power bases centralized delivery system, have been studied on security and stability control. This paper mainly includes the following aspects:1) The model and operating characteristics of the doubly-fed induction generator are analyzed. Then, advanced branch transient energy function is deduced. Moreover, by using advanced branch transient energy function, tripping machines under serious failure are analyzed. The different tripping effects on accelerating energy between DFIG and conventional thermal generator are illustrated.2) The impacts which are made by wind power penetration on system recovery process and tripping control are analyzed. For transient tripping control of Wind&Fire bundled delivery system, a decision-making model of transient optimal tripping control considering Wind&Fire coordination and a practical calculation process are proposed.3) For a practical example of Wind&Fire bundled delivery system, the transient stability checking calculation is simulated via PASAP. For over line fault between TS and SY of this example, the impacts on different tripping schemes are compared. By using the decision-making model of transient optimal tripping control considering Wind&Fire coordination, transient optimal tripping scheme has been found. It shows that the decision-making of transient optimal tripping has a good practicability.4) For a practical example of large-scale wind power centralized delivery, the calculations between before and after series compensation under the situation of winter peak load power are compared. The effects of series compensation technology on improving node voltages of long-distance wind power centralized delivery system are illustrated. Then, the transient stability checking calculation is simulated. The capacity of wind power centralized delivery for different degrees of series compensation are calculated.