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Sub-synchronous control interaction (SSCI) is an interaction between a power electronic control system and a series-compensated electrical network. This issue has gained attention due to the recent SSCI phenomena reported in doubly fed induction generator (DFIG)-based wind farms connected to series-compensated lines. To suppress SSCI, this paper proposes the design and implementation of a novel control strategy for optimizing the robust characteristics of converter controller using the active disturbance rejection control (ADRC). In this control framework, the extended state observer is designed for state observation and disturbance estimation. Then, a nonlinear state-error feedback function is constructed to further improve the tracking performance of the system. Simulations and experimental results show that the ADRC performance is better than the traditional proportional integral (PI) controller. The ADRC is able to properly damp the SSCI of DFIG wind turbines by improving the robustness without the need of expensive additional damping devices.

The scenario of power system pre-scheduling can realize the simulation and validation of the accident anticipated plan. This paper realizes the automatic execution of accident anticipated plan. Firstly, starting with the key elements of accident anticipated plan text, this paper analyses and establishes a structured accident anticipated plan model. Based on natural language processing (NLP) technology, it matches the structured model and transforms the accident anticipated plan text into electronic structured model information. On basis of the dispatching rules, the quantitative calculation method of automatic reasoning for different operation instructions is proposed. Finally, the event time model is established to realize the fast sequential simulation.

With the rapid construction of UHV AC-DC interconnected power grids, it is increasingly important to ensure the voltage stability of interconnected systems. In this paper, a continuous power flow algorithm for voltage-source converter (VSC) AC-DC system considering static load characteristics is proposed. It establishes an index for evaluating voltage stability based on the load margin and identified the weak region of the system. The effects of load model changes on voltage stability (VS) are analyzed in various scenarios. The relationship between DC control mode and system VS is further considered. The effectiveness of the proposed method is verified by an improved 10-node example.

Economic operation of complicated distribution network is an important problem. A bilevel optimal operation model of complicated distribution networks with microgrids integration is built. In the model, the day-ahead optimal operation of complicated distribution networks is on the upper-level and the optimal operation of the microgrid is on the lower-level. Electricity exchange price constraints are considered in this model. Further, in order to overcome negative influences brought by the volatility of renewable distributed generators, electric vehicles are adopted to balance the volatility. The proposed bilevel optimal operation model is solved by particles swarm optimization based on bilevel iterative algorithm (BIA-PSO). The demonstration is performed on a modified IEEE 33-node radial distribution network with microgird integration.