No abstract

In this paper, the control strategy to improve voltage stability of power system was studied after large scale wind power plants integrated. And the strategies to improve the transient voltage stability of wind power plants were introduced firstly. Based on the analysis of characteristics that voltage stability of the fix speed wind generator, a new control strategy that can improve the voltage stability of the power system containing large-scale wind power plants was proposed by employing permanent magnet synchronous generators(PMSG) together with static compensator(STATCOM). The stability of transient voltage can be improved by using full power wind turbine close to generators to provide reactive power. STATCOM control model, fixed-speed wind turbine model and the model of permanent magnet were established, the voltage stability of wind power plants can be improved using full power permanent magnet synchronous generator with together STATCOM to provide reactive power compensation to constant speed wind during disturbance. The simulation carried out on the test system verify the proposed control strategy can effectively enhance the transient voltage stability of the power plants containing large scale wind generators.

As traditional fossil energy sources such as coal cause serious environmental pollution, it is a major trend to promote the construction of a ‘clean’ power system with new energy sources as the mainstay. However, the uncertainty of intermittent energy output and its high proportion of grid connection bring challenges to the scheduling operation of the power system. In this paper, the authors propose a two‐stage robust dispatching strategy for the combined wind‐photovoltaic‐fired‐pumped storage system to improve the capacity of renewable energy (RER). The outer layer of the model is based on minimizing the start‐stop cost of thermal power units to obtain the start‐stop scheme of thermal power units, and the inner layer of the model integrates the system operation cost, pollutant emission cost, deviation penalty, and other constraints of wind power and PV output to obtain the dispatching scheme with the lowest overall operation cost under the worst scenario of wind power and PV fluctuation. The model is solved alternatively by column constraint generation algorithm (C&CG) and strong pairwise theory. The feasibility and effectiveness of the proposed method was verified based on the improved 30‐machine test system as an example.

The integration of high proportion renewable energy not only brings many benefits, but also increases the difficulty of power system stability analysis. One of the reasons for this problem is the unclear internal characteristics of new energy equipment. Therefore, there is an urgent need for a more detailed analysis of the characteristics of new energy equipment. Taking a double-fed induction generator (DFIG), which has complex operation characteristics and is widely used, as an example, a detailed energy function (DEF) of DFIG for small signal stability analysis is proposed in this paper. This method performs DFIG's internal energy analysis, making the traditional energy structure more comprehensive. On this basis, the internal parameters of DFIG with high sensitivity to stability are obtained, and the damping evaluation index is constructed to evaluate the damping of DFIG. Finally, the proposed model's correctness and method are verified in the 4-generator 2-area system.

Considering the strong nonlinearity of power oscillation in power system containing static synchronous series compensator and nonlinear factors, a novel power oscillation damping controller that exhibits nonlinearity and robustness is proposed to reduce power oscillation in such systems. First, use objective holographic feedback on the system state equation to obtain system model. Second, nonlinear factors and external disturbances are estimated using direct feedback linearization to achieve linearization of the nonlinear model. Third, H N equation should be selected. Finally, a power oscillation damping controller of static synchronous series compensator is designed on direct feedback linearization, objective holographic feedback theory-H N . The controller exhibits good dynamic performance and robustness. Simulations on four-generator two-area system are conducted under various disturbances to prove the effectiveness and robustness of the proposed damping control method.