Advanced Materials Research Vols. 724-725

Abstract: According to the operation features that voltage of wind farm fluctuate greatly, we analyzed the operation features of reactive power compensation equipment and put forward the coordination control method of compensation equipment. The method solved the problem for a single for reactive compensation equipment caused by the slow speed and poor economy. Based on the target of safe and economical operation, we raised that using composite indicator calculate the capacity of all kinds of required compensation equipment, and then we had coordinated control to compensation equipments. This paper gave an example of Guazhou Gansu and tested and verified the feasibility and effectivity of the method.

Abstract: Wavelet transform was a signal analysis method from domain of time-frequency which was better in the wavelet packet, vibration signal was a carrier of fault features of the wind turbine driving chain, can effectively reflect most of the fault information of the wind turbine drive train. Wavelet transform for feature extraction was proposed as the characteristics of wind turbines in the presence of a large number of transient and non-stationary signals. The SCIG vector control system was designed and the simulation result shows this control system can realize optimal control for large wind energy conversion system which can effectively applied into SCIG wind power generation system for system modification.

Abstract: Platform structure is the basic guarantee for safety operation of offshore wind turbine. Based on the boundary element method and combined with multi-body dynamics, analyzing motion response and wave force mechanism to the platform structure, and obtained the dynamic response and the wave force change of the platform structures in time domain, last analyzes the motion response and wave force change of tension leg platform in surge, sway and heave also roll, pitch and yaw direction. The results show that the maximum response of sway and the minimum response of surge have the same direction, it is the same with the maximum response of pitch and the minimum response of roll ; Motion responses of heave and yaw change not as acutely as other four directions ; In time-domain variation range, motion response of surge, heave and pitch change acutely, while motion responses of sway, roll and yaw change slightly. Wave force focus mostly in heave and pitch direction. The results is high reference value on offshore tension leg platform structural design and optimization.

Abstract: With the increased installed capacity of wind power in power system, determining optimal spinning reserve capacity is one of the most important problems in operation of electricity power system. CVaR (conditional value at risk) is introduced to calculate the risk of the cost associated with load shed and abandoning wind power with the consideration of load and wind power prediction uncertainties. Portfolio theory based on CVaR is used to build the Cost-CVaR model. Efficient frontier, which can support the system operators (SO) with the decision of optimal spinning reserve, can be obtained by solving the Cost-CVaR model. The analysis of RTS example can demonstrate the usefulness and efficiency of the model.

Abstract: The application of power communication system in the field of wind power mainly includes the overall system communication and local field communication. During the operation of wind farms, the total system requires that the electric power communication system should provide reliable rapid information channel, accuracy of transmission on a variety of digital business. This article will focus on the application of power communication system between the wind turbine and the booster station, which includes optical fiber communication, communication and leased public circuit, as well as the cable communication, wireless communication, microwave wireless communication. Finally, in the premise of various communications comparison, according to the actual situation of the wind power field, the network transmission rate and reliability should be considered to the requirements of power market.

Abstract: In this paper, a variable speed wind turbine model based on doubly-fed induction generator (DFIG) and a section of a practical power grid model to be studied are implemented in DIgSILENT / PowerFactory. The static voltage stability and the transient voltage stability of the regional power grid with high wind power penetration will be studied. Moreover, this paper will focus on the impact of static var compensator (SVC) on both steady state voltage stability and transient voltage stability.

Abstract: For the reserve capacity optimization problem of regional power system with wind farms, a joint optimization model was establishes which can effectively reduce the reserve capacity requirements of the regional power system with wind farms. This model was based on chance constrained programming method ,and quantified the processes that subsystems without wind farms providing reserve capacity support to subsystem with wind farms, each subsystem was conditioned by the level of security and stability, and the security constraints of regional system were also comprehensively considered. Monte-Carlo stochastic simulation model of genetic algorithm was used to solve the model. The model was tested by an example, and the results achieved the expected, which shows the model has a high reference value for the reserve capacity optimization of the power system with wind farms.

Abstract: Research of wind power prediction has great significance for power balance and economic operation. This paper combined the ARMA model and the neural network model to establish a wavelet-ARMA model revised by neural network. After decomposing the historical wind power data by wavelet analysis, the high frequency components and low frequency components were separately predicted by ARMA. The reconstructed predictive outcomes were revised by BP neural network. To improve the accuracy, the predictive values of predictive moments were added to the BP neural network. This paper gave a 96 points rolling prediction for a single wind turbine. The accuracy of the results is 84.17%, and the pass rate is 87.50%. Compared to the single predictive methods, they are increased by 2%-4% and 3%-9% respectively in combination predictive model.

Abstract: A conceptual design of tritium-breeder blanket for prototype DEMO is introduced. In this concept, Li4SiO4 pebbles are chosen as tritium-breeder material and Be for neutron multiplication. To confirm the thermal effectiveness,a CFD code FLUENT is used for the calculation. The result indicated that, the thermal effectiveness of the concept is acceptable.

Abstract: The thermo-hydraulic performance of the first wall for CH HCSB TMB was investigated, corresponding analysis have been carried out using CFX, a computational fluid dynamics (CFD) code. The simulation results show that the maximum temperature 565°C of the FW is slightly above the allowable temperature limit 550°C of material. Base on the results so far, a modified design of the FW was presented, in which the radial-toroidal direction of cooling channels was changed to radial-poloidal. The thermo-hydraulic computational results show the temperature of the FW with modified design decrease over all, and the maximum temperature 504°C was below the allowable temperature limit for structural material. It is found that the modified design for the FW is reasonable so that the FW is effectively cooled.