| Non-renewable energy is depleted day by day,energy shortage and environmental pollution are serious.Solar energy has become the most promising renewable energy in the world because of its advantages of pollution-free,no noise,simple maintenance and huge reserves.As the installed capacity of photovoltaic power plants continues to increase,the penetration rate of photovoltaic power sources in the grid continues to increase.In order to improve the stability of the power system,it is necessary to conduct in-depth research on photovoltaic grid-connected LowVoltage Ride-Through(LVRT)technology.the study.This paper mainly studies the low voltage ride-through of photovoltaic grid-connected power generation system with hybrid energy storage of Superconducting Magnetic Energy Storage(SMES)and Battery Energy Storage System(BESS),and uses improved resistive superconducting The current limiter(Superconducting Fault Current Limiter,SCFCL)and improved state assessment realize quench protection for the superconducting energy storage coil,thereby realizing the low voltage ride through of the SMES-BESS hybrid energy storage photovoltaic grid-connected system.This article first describes the characteristics of photovoltaic grid-connected,analyzes the low voltage ride-through control strategy of photovoltaic grid-connected systems of SMES-BESS hybrid energy storage,and studies the photovoltaic gridconnected low voltage ride-through characteristics of hybrid energy storage under symmetrical and asymmetrical grid voltage drops.The SMES quench protection strategy with improved SMES state evaluation and improved resistive SCFCL is proposed to ensure the normal progress of the low voltage ride through.The low voltage ride through characteristics of the SMES-BESS hybrid energy storage system with only state evaluation and only improved resistive SCFCL are studied.,A combination of improved condition assessment and improved resistive SCFCL is proposed for low voltage ride through.This paper uses MATLAB/Simulink to conduct a simulation study,and simulates and verifies the low voltage ride-through strategy combining the improved resistive SCFCL and the improved SMES state assessment to ensure the power response of the SMES during the low voltage ride-through period and stabilize the DC bus of the inverter.Voltage and photovoltaic output power,suppress the harmonic content of grid-connected current,enhance the stability of photovoltaic grid-connected system,and ensure the normal operation of low voltage ride through.The simulation results show that the proposed low voltage ride through method is practical and feasible.In addition,the critical current test experiment was carried out on the Bi2223/Ag superconducting coil,the inductance measurement experiment was carried out on the Bi2223/Ag superconducting coil,and the resistance type SCFCL quench characteristic experiment was also carried out.The experiment verified that the resistance type SCFCL can effectively prevent superconductivity.The energy storage coil quench provides a favorable guarantee for the low voltage ride through of the SMES-BESS hybrid energy storage photovoltaic grid-connected power generation system,and provides an experimental basis for the simulation research of this article.This paper proposes the low voltage ride-through method of the SMES-BESS hybrid energy storage system for photovoltaic grid-connected systems,and proposes a combination of improved resistive SCFCL and improved SMES state assessment to prevent SMES’s superconducting energy storage coil from quenching and ensure that SMES is in photovoltaics The power response during the low voltage ride through of the grid-connected system enables the SMES-BESS hybrid energy storage photovoltaic grid-connected power generation system to achieve low voltage ridethrough,which enhances the stability of the photovoltaic grid-connected system. |
