Voltage Stability Of Wind Farm Research Articles

STATCOM APPLICATION TO INCREASE VOLTAGE STABILTY OF WIND FARMS

The integration ratio of wind farms to the grid is increased tremendously derived by the need for cleaner and renewable energy. However, the stability of the grid is a major concern due to large wind and other renewable resource-based power plants. Thus, wind turbine generators must adhere to the regulations of other conventional forms of generation. To boost stability, especially voltage-based, Flexible AC Transmission Systems such as Static Var Compensators (SVC) or Static Synchronous Compensator (STATCOM) are put in the vicinity of the wind farm's connection point to the grid. This study is intended to model and simulate dynamically a wind farm using the Doubly Fed Induction Generator (DFIG) turbine type and STATCOM under faulty conditions. The model is implemented inside the DigSILENT Power Factory simulation tool. The results show that STATCOM can improve the voltage stability of wind farms at the point of connection to the grid.

Research on Control Strategy of Hybrid Reactive Power Compensation System for Wind Farms

With the increasing scale of wind farms and the increasing proportion of wind power generation in the energy system, the grid has higher and higher requirements for the voltage stability of wind farms. In this paper, we propose a hybrid reactive power compensation system and its control strategy for weakly connected asynchronous wind farms, which can effectively control the compensation cost while improving the continuity of reactive power regulation. It also verifies the correctness and feasibility of the proposed hybrid reactive power compensation system and its control strategy through simulation.

Analysis of Influencing Factors on Transient Voltage Stability of a Grid-connected DFIG-based Wind Farm

A simulation model of WSCC three-machine nine-node system integrated with a wind farm based on double fed induction generator (DFIG) was established using the power system analysis toolbox PSAT, and the outlet bus of DFIG was set as PV node. Some influencing factors on the transient voltage stability of grid-connected wind farm were analyzed, when short circuit fault occurs in the power grid side. The results show that fault clearing time, capacity of wind farm, location of short circuit fault, and reactive power compensation have all influences on the transient voltage stability of the wind farm. According to different locations of short circuit in the power grid, the grid-connected wind farm has different minimum capacity which can guarantee the transient voltage stability. The static var compensator (SVC) installed in the wind farm can improve the transient voltage stability only for the short circuit point which is far from the grid entry point of wind farm in electrical distance.

风电场无功电压模糊多目标决策方法

针对风电场并网运行难以有效兼顾稳定性与经济性的问题，提出了风电场运行经济性和稳定性目标，其中经济性目标考虑风电场有功损耗指标，稳定性目标考虑风电场无功源无功裕度和风电场电压偏差两个指标。在此基础上，建立了风电场无功电压多目标优化控制模型。该模型以SVC与双馈风电机组的无功功率为控制对象，运用模糊多目标决策方法将风电场无功电压优化转换为一个多目标、多约束的非线性规划问题，并采用粒子群算法进行求解。仿真算例结果表明，所提出的优化决策方法能够实现风电场运行经济性和稳定性的双重目标，在提高风电场电压稳定性的同时，合理降低了风电场损耗。 To solve stability and economy coordinated problem caused by wind farm integration, the targets of stability and economy are put forward, in which economy target considers active power loss, and stability target includes reactive power reserve capacity and voltage deviation of wind farm. Based on this, an optimization control model of reactive power and voltage fuzzy multi-objective decision making method of wind farm is established, in which the reactive power of SVC and DFIG are taken as control objectives, and the fuzzy multi-objective decision making method is used to convert the optimization of reactive power and voltage into a multi-objective and multi-constrained nonlinear programming problem. The particle swarm algorithm (PSO) is adopted to solve the built model. The simulation example results show that the proposed method can achieve the dual targets of economy and stability of wind farms, and can improve the voltage stability of wind farms, and reasonably re-duce the power loss of wind farms.

Comparative Study of the Behavior of a Wind Farm Integrating Three Different FACTS Devices

Improving grid connection of wind farms is a relevant issue to be addressed, especially for fixed-speed wind turbines. Certain elements, such as FACTS (Flexible AC Transmission Systems), are able to perform voltage and reactive power regulation in order to support voltage stability of wind farms, and compensate reactive power consumption from the grid. Several devices are grouped under the name of FACTS, which embrace different technologies and operating principles. Here, three of them are evaluated and compared, namely STATCOM (Static Synchronous Compensator), SVC (Static Var Compensator) and SSSC (Static Synchronous Series Compensator). They have been modeled in MATLAB / Simulink, and simulated under various scenarios, regarding both normal operation and grid fault conditions. Their response is studied together with the case when no FACTS are implemented. Results show that SSSC improves the voltage stability of the wind farm, whereas STATCOM and SVC provide additional reactive power.

Improvement of Transient Voltage Stability of the Wind Farm Using SVC

Static var compensator (SVC) is used to improve transient voltage stability of the asynchronous wind farm. The issue of voltage stability and transient stability of wind power system are also addressed. A novel control strategy of SVC is proposed instead of the types of traditional feedforward and uniline feedback to control SVC. The proposed method makes control performance better and the compensation efficiency higher. At the same time, balanced compensation strategy of orientation vector conversion is applied instead of traditional model of steady-state phasor to calculate the compensation electrical susceptance. Using this method can overcome the shortcoming of dynamic characteristics and adaptability. At last, the simulation results indicate this control strategy could improve the stability of wind farm effectively and quickly.