Research On Location And Capacity Determination Strategy Of Distributed Condenser Of New Energy Power System Considering Frequency Stability

The proposal of the "dual carbon" goal has accelerated the integration of new energy generation represented by wind and solar power into the grid.The low-carbon transformation of the energy system will be an important strategy for the development of the national energy system.The grid connection of new energy generation with a high proportion of power electronic interfaces will lead to weak inertia support capacity and prominent frequency stability issues in the power system.Frequency safety refers to the ability of the system’s frequency to be maintained or restored within the allowable range when there is serious interference in the power grid and active power imbalance occurs,preventing frequency collapse.For wind and solar power stations,distributed synchronous condensers serve as rotating components that not only provide voltage support,but also provide rotational inertia for the system.By configuring condensers,the system’s inertia level can be effectively improved,thereby enhancing the frequency support strength of the power grid.However,in the current power system,the configuration method of distributed condensers still needs to be studied,and it is of great significance to develop an efficient and feasible location and capacity determination strategy for distributed condensers.This thesis proposes a distributed condenser location and capacity determination method that considers frequency stability constraints.The system inertia distribution is evaluated using node inertia theory,and the weak inertia areas are searched for to guide condenser location.Then,the condenser capacity is planned with the goal of minimizing investment cost.The example analysis shows that the proposed method can efficiently enhance the frequency support strength of the high proportion new energy system and improve the frequency safety during system operation by configuring fewer condensers.The main research work of this thesis includes the following aspects:1)Elaborate on the background of the project,briefly introduce the adverse effects of the decrease in inertia level of the power system caused by the high proportion of new energy integration on the frequency control of the power system,and the supporting ability of the synchronous condenser on the system frequency response,indicating the necessity of selecting this project.Subsequently,a review was conducted on the frequency stability analysis methods of the power system and the current research status of synchronous condensers,clarifying the feasibility of this project.2)This thesis provides an overview of the frequency stability of the power system,provides a detailed introduction to the characteristics of the dynamic frequency response of the power system,and analyzes the impact of high proportion of new energy access on the frequency response characteristics of the power system.Subsequently,the power system node inertia index for evaluating the inertia level of the system was introduced,and a critical inertia for system stability was proposed based on the constraint of frequency stability,providing a theoretical basis for subsequent distributed condenser location and capacity determination strategies.3)The composition and inertia response principle of the synchronous condenser system were analyzed in detail,and the influence of different capacities and grid connection positions of the synchronous condenser on the frequency stability characteristics of the power system was analyzed using numerical examples.The simulation results verified that different capacities of the synchronous condenser connected to the system had different effects on frequency response,and the different positions of the synchronous condenser connected to the system also had different effects on frequency response,This provides a necessity for the subsequent research on the configuration strategy of location and capacity determination for distributed condensers.4)On the basis of clarifying the impact of synchronous condenser grid connection on the frequency stability characteristics of the power system,a sensitivity index for the grid connection position of distributed condensers to node inertia is constructed,providing a theoretical basis for the location selection of distributed condensers.And the node inertia of the simulation example was calculated,and the inertia distribution of the system was evaluated.Based on this,with the minimum configuration capacity as the optimization objective and the critical inertia as the constraint condition,the Grey Wolf optimization algorithm was used to construct the optimal location and capacity determination scheme,achieving effective regulation of power system frequency stability.Finally,the feasibility of the proposed distributed condenser location and capacity determination strategy was verified in a numerical example.