| The grid-side battery energy storage power station has the characteristics of high adjustment accuracy,fast response speed,and flexible application.It can be applied to scenarios such as power peaking,frequency modulation,voltage regulation,and improvement of renewable energy consumption capacity.And it has a unique fourquadrant active and reactive power adjustment capability and millisecond response capability,which can effectively control the system voltage,improve the voltage regulation capability of the power grid and the transient voltage stability level.Therefore,this paper studies the control strategies of grid-side energy storage power stations participating in grid steady-state and transient voltage regulation.First of all,three types of energy storage models suitable for different scenarios and different time scales were constructed,including transient models of energy storage systems based on PQ(active and reactive)control,and dynamic models of energy storage voltage regulation for long-term simulation needs.As well as the energy storage temporary stability model that reflects the characteristics of energy storage rate,it lays the foundation for the research of energy storage participating in grid voltage regulation.Secondly,a coordinated control strategy for energy storage applied to power grid voltage regulation and dynamic reactive power support is proposed.Taking the grid voltage stability as a constraint,the goal is to provide reactive power support to the grid quickly and accurately,and a basic reactive power control strategy is proposed.;On this basis,construct voltage state awareness indicators to accurately describe the current power grid operating state,and then identify the power grid state and propose a coordinated reactive power control strategy.The simulation results show that the energy storage reactive power output scheme dynamically formulated according to this strategy can realize adaptive voltage regulation and dynamic reactive power support under emergency fault conditions.Compared with the traditional droop control,it can greatly improve the grid voltage performance.Thirdly,a control strategy of energy storage power station and Automatic Voltage Control(AVC)system joint regulation to participate in the steady-state voltage regulation of the power grid is proposed.Based on feature extraction,the current power grid operating state can be sensed and judged,and the time series coordination method is adopted Coordinate control of discrete reactive power sources and energy storage power stations to participate in grid voltage regulation;construct a control strategy for energy storage to balance reactive power on-site in the dead zone of voltage regulation,and design the maximum reactive power constraint based on real-time bus voltage feedback using Logistic function.This strategy fully combines and takes advantage of the continuous and rapid reactive power output characteristics of the energy storage power station and the large capacity of the capacitor / reactor,and realizes the joint voltage regulation of the energy storage power station and the traditional voltage regulation method,which can avoid the frequent investment of the capacitor / reactor Cut,and achieve reactive power balance in the dead zone of voltage regulation,simulation verified the effectiveness of the strategy.Finally,taking Hunan Power Grid as an example,the impact of large-scale battery energy storage on improving the transient voltage stability of a large power grid is studied and analyzed.The power system analysis software package(PSASP)was used to simulate the transient stability of Hunan Power Grid.The characteristics of the transient voltage stability problem in Hunan Province and the effect of increasing the proportion of DC power receiving on the transient voltage stability of Hunan were analyzed.Based on the sensitivity analysis,the site selection of the energy storage power station was analyzed.Finally,the energy storage transient stability model was connected to the Hunan power grid topology for simulation,which verified the effectiveness of large-scale energy storage in improving the transient voltage stability of the large power grid. |
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