Research On A Novel Wind Power Grid-connection System Using Inductive Filtering Technology

Vigorously developing renewable industries,such as wind power generateon,play an important role in contributing to the sustainable development and green low-carbon transformation of the energy industry.However,due to the random and volatility nature of wind power generation and the uniqueness of its control system,when it is connected to the grid on a wide scale,it will reduce the power quality at the point of common coupling and affect the stability of the power system,which is not beneficial to the secure and reliable operation of the power grid.To solve the above problems and overcome the defects of the traditional schemes,this paper proposes a novel wind power grid-connection system using inductive filtering technology.The research is carried out on the harmonics,reactive power characteristics and grid-connection stability of the proposed system from both theoretical and engineering practice aspects,and the viability of the proposed system is proved in terms of both simulation and engineering applications.The research work in this paper focuses on the following four aspects.1.The harmonic characteristics of the wind power grid-connection system are studied,the theoretical analysis is verified and the simulation system is calibrated by engineering test data.The structure,key equipment and control methods of the wind power grid-connection system are discussed in detail,and the harmonic generation mechanism of the wind power grid-connection system is revealed.A doubly-fed induction generator model is established,and the harmonic characteristics of the wind power grid-connection system are systematically studied by using the measured data of the practical system,so as to grasp the typical harmonic distribution,which provides the basis for the design of the novel wind power grid-connection system below.2.A novel wind power grid-connection system using inductive filtering technology is proposed,and its steady-state operation mechanism is explored.Based on the topology of the novel wind power grid-connection system,the equivalent circuit and mathematical modeling are established,and the conditions for the implementation of inductive filtering technology are discussed.By defining the sensitivity factors of filtering performance and based on the measured data and the actual system parameters,the harmonics filtering and resonance damping performance of the proposed system under the variation of grid-side impedance and internal parameters are studied in depth.It shows that the proposed system has steady-state harmonics filtering performance,antidisturbance capability and excellent grid-connection compatibility.3.The impedance model of the proposed novel wind power grid-connection system is established,and the interaction mechanism between the system and the unity grid is studied in detail.Based on the topology and system parameters of the real wind power grid-connection system,the impedance model of the novel wind power grid-connection system using inductive filtering technology is established.The influence of the grid short-circuit ratio on the stability of the proposed system is investigated by using the impedance analysis and verified by simulation.4.The simulation analysis and engineering test research of the proposed system were carried out.The simulation model of the novel wind power gridconnection system is established,and the systematic simulation study on the harmonic and reactive power characteristics of the system is conducted to verify the correctness of the theoretical study in this paper.Then,taking an actual wind farm that adopts the proposed scheme as the research object,the operation data of the wind farm in the worst month of power quality in a year is evaluated,and the findings show that all key power quality indicators are better than the national standards,thus verifying the validity and practicability of the proposed system.Since it came into operation,the system has been in good operation condition,and all performance parameters have reached or better than national standards,providing a feasible new technical pathway for the integrated utilization of wind power resources.