外文翻譯---大型風(fēng)電場(chǎng)的瞬時(shí)穩(wěn)定和模擬

1、1Modelling and transient stability of large wind farms1. IntroductionDenmark has currently about 2300 MW wind power capacity in on-land and few offshore settings, which corresponds to more than 20% of power consumption(i

2、n average). Further, construction of two large-scale offshore wind farms of 150 MW power capacity each has been announced. The first large offshore wind farm in Denmark will be constructed at Homs Rev by the year 2002 in

3、 the area of the system operator ELTRA .This will be followed by the first in the area of the Eastern Danish system operator ,ELKRAFT System ,large offshore wind farm at Rodsand by the year 2003.The installed capacity in

4、 on-land settings and in combined heat-power units(UHP)will increase as well, whilst the power production and control ability of the conventional power plants with respect to voltage and frequency are reduced . In the ye

5、ars to come ,the power production pattern in the Danish power system will change from the power supply from conventional power plants―as it is known today―to a power supply mix, where about 30-40%of power consumption(in

6、average) is covered by wind power. In other words, the power technology will undergo changes from a well-known technology built-up about conventional power plants to a partly unknown technology―wind power.In the year to

7、come it will be focusing on maintaining power system stability and voltage stability, for example at a short circuit fault, ensuring power supply safety and other important tasks as amount of wind power is drastically in

8、creasing. This situation makes it necessary to find solutions with respect to maintaining dynamic stability of the power system with large amount of wind power and its reliable operation. These solutions are based on a n

9、umber of requirements that are formulated with respect to operation of the large offshore wind farms and the external power system in case of failure events in the external system.The paper contains separate subjects dea

10、ling with design of windmills for large offshore applications and their control that shall be taken into account with respect to improving the short-term voltage stability.2. system stability requirements In terms of sho

11、rt-term voltage stability, the major goal is the voltage re-establishing 3adjust the set-points of the wind turbines by the blade by the blade angle adjustments.The complete representation of the wind farm is chosen beca

12、use the commonly asked question concerning large wind farms is whether there can be electromechanical interaction between a large number of the closely placed windmills excited by disturbances in the power system when th

13、e windmills are working at different set-points, equipped with relatively soft shafts and even having different mechanical data, and equipped with control systems, for instance pitch.The model of the offshore wind farm i

14、s implemented in the dynamic simulation tool PSS/E and consists of 80 wind turbines of 2MW power capacity each, see Fig.1.Each wind turbine is simulated by a physical windmill model consisting of :1. the induction genera

15、tor model with representation of the stator transients,2. the windmill shaft system model,3. the aerodynamic model of the wind turbine,4. the pitch control system given by the control logic and the blade servo.For comput

16、ation of wind turbine aerodynamics there are used airfoil data for a 2 MW pitch windmill equipped with an induction generator.Each wind turbine is via its 0.7 KV/30KV connected to the wind farm internal network. The inte

17、rnal network is organised in eight rows with 10 wind turbines in each row. Within the rows, the wind turbines are connected through the 30 KV sea cables. The distance between two wind turbines in the same row is 500 m an

18、d the distance between two rows is 850 m.The rows are through the 30 KV sea cables connected to the offshore platform with 30 KV/132 KV transformer and, then, through the 132 KV sea/underground cable to the connection po

19、int in the transmission system on-land. There is chosen an ac-connection of the offshore wind farm to the transmission network.An irregular wind distribution over the wind farm area there is assumed since the wind turbin

20、es are shadowing each other for incoming wind. The efficiency of the wind farm is 93%at the given wind distribution and the power production pattern is shown in Fig.1.Furthermore, the windmill induction generators have a