This letter studies large-disturbance stability of the power system with a synchronous generator(SG)and a converter-interfaced generation(CIG)connected to infinite bus.The power system is multi-timescale and first sim...This letter studies large-disturbance stability of the power system with a synchronous generator(SG)and a converter-interfaced generation(CIG)connected to infinite bus.The power system is multi-timescale and first simplified.It is shown that the boundary of region of attraction(ROA)of the simplified model is composed of stable manifolds of unstable equilibrium point(UEP)or semi-singular point(SSP),named anchor points,and singular surface pieces.The type of anchor point determines the dominant instability pattern of the power system.When the anchor point is UEP or SSP,the dominant instability pattern is the instability of rotor angle of SG or the instability of phase-locked loop and outer control loop(OCL)of CIG,respectively.Transition of dominant instability pattern can be analyzed with the relative position relationship between UEP and SSP.The effect of OCL is discussed.When the OCL is activated,the ROA becomes smaller and the system is more prone to instability of CIG.It is necessary to consider the OCL when studying the large-disturbance stability of the power system.展开更多
This paper presents a controller model of asymmetric current injection for converter-interfaced generators suitable for root-mean-square(RMS)phasor-domain,fundamentalfrequency,three-phase,and dynamic simulation tools....This paper presents a controller model of asymmetric current injection for converter-interfaced generators suitable for root-mean-square(RMS)phasor-domain,fundamentalfrequency,three-phase,and dynamic simulation tools.The effectiveness of the proposed controller is assessed with simulations in test systems with high percentage of converter-interfaced generation.The simulations focus on the operation of protection relays that use negative-sequence quantities in their directional elements.This paper also presents and compares two strategies to limit reactive negative-sequence currents,and active and reactive positive-sequence currents.A tutorial test system and a regional system part of the actual Brazilian Interconnected Power System are used to assess the correctness of the proposed controller in three-phase fundamental-frequency RMS dynamic simulations.展开更多
Grid-forming(GFM)control is a key technique for power systems with high penetration of converter-interfaced generation.However,its application to photovoltaic(PV)systems faces challenges related to DC voltage transien...Grid-forming(GFM)control is a key technique for power systems with high penetration of converter-interfaced generation.However,its application to photovoltaic(PV)systems faces challenges related to DC voltage transient stability.This paper investigates a common countermeasure involving a PI-based DC voltage controller for GFM-PV systems,revealing that their small-signal stability is sensitive to parameter tuning.The study develops a generalized DC voltage-dominated 2nd-order GFM model and successfully conducts complex torque analysis,showing that this approach can be effectively extended to other dynamics governed by DC voltage-dominated GFM systems.Subsequently,the paper establishes a stability criterion for GFM-PV systems and proposes a parameter tuning method for DC voltage controllers that incorporates damping margin considerations.The performance of the tuned single-machine-infinite-bus GFM-PV system is validated on the RT-LAB real-time simulation platform under scenarios involving solar irradiance fluctuations and grid frequency disturbances.The proposed method proves effective in ensuring the stability of the GFM-PV system,with robust theoretical support.展开更多
In recent years,transmission system operators have started requesting converter-interfaced generators(CIGs)to participate in grid services such as power oscillation damping(POD).As power systems are prone to topology ...In recent years,transmission system operators have started requesting converter-interfaced generators(CIGs)to participate in grid services such as power oscillation damping(POD).As power systems are prone to topology changes because of connection and disconnection of generators and lines,one of the most important requirements in the design of POD controller is to account for these changes.This can be done by either adjusting the controller structure during the operation or applying a fixed structure designed to address changes in the system.The fixed structure is usually preferred by transmission system operators since it is easier to determine its impact on the system.In this paper,a design procedure is proposed for network-reconfiguration-aware POD controller with fixed structure for CIG-based power plants that considers network configurations with any one line disconnected.The design procedure is based on frequency-response techniques,so it is suitable for application in CIG-based power plants,even in cases when a detailed small-signal model of the system is not available.Designs of a POD controller for the damping of critical system modes can be obtained by using active power,reactive power,or both power components simultaneously.The application to the design of a POD controller for a CIG-based power plant connected to the IEEE 39-bus system is presented as an example.Simulations performed in MATLAB and SimPowerSystems are used to validate the proposed design procedure.The validation includes an analysis of system performance with changes considered in the proposed designed procedure.Also,the system performance under unconsidered changes is examined,covering variations in load and inertia values,as well as disconnection of synchronous generators.展开更多
基金supported by the National Natural Science Foundation of China(No.U2066602)。
文摘This letter studies large-disturbance stability of the power system with a synchronous generator(SG)and a converter-interfaced generation(CIG)connected to infinite bus.The power system is multi-timescale and first simplified.It is shown that the boundary of region of attraction(ROA)of the simplified model is composed of stable manifolds of unstable equilibrium point(UEP)or semi-singular point(SSP),named anchor points,and singular surface pieces.The type of anchor point determines the dominant instability pattern of the power system.When the anchor point is UEP or SSP,the dominant instability pattern is the instability of rotor angle of SG or the instability of phase-locked loop and outer control loop(OCL)of CIG,respectively.Transition of dominant instability pattern can be analyzed with the relative position relationship between UEP and SSP.The effect of OCL is discussed.When the OCL is activated,the ROA becomes smaller and the system is more prone to instability of CIG.It is necessary to consider the OCL when studying the large-disturbance stability of the power system.
基金supported by CNPQ,FAPERJ and Coordenacao de Aperfeicoamento de Pessoal de Nível Superior–Brasil(CAPES)Finance Code 001。
文摘This paper presents a controller model of asymmetric current injection for converter-interfaced generators suitable for root-mean-square(RMS)phasor-domain,fundamentalfrequency,three-phase,and dynamic simulation tools.The effectiveness of the proposed controller is assessed with simulations in test systems with high percentage of converter-interfaced generation.The simulations focus on the operation of protection relays that use negative-sequence quantities in their directional elements.This paper also presents and compares two strategies to limit reactive negative-sequence currents,and active and reactive positive-sequence currents.A tutorial test system and a regional system part of the actual Brazilian Interconnected Power System are used to assess the correctness of the proposed controller in three-phase fundamental-frequency RMS dynamic simulations.
基金supported in part by Northeast Branch of State Grid Corporation of China(52992624000W).
文摘Grid-forming(GFM)control is a key technique for power systems with high penetration of converter-interfaced generation.However,its application to photovoltaic(PV)systems faces challenges related to DC voltage transient stability.This paper investigates a common countermeasure involving a PI-based DC voltage controller for GFM-PV systems,revealing that their small-signal stability is sensitive to parameter tuning.The study develops a generalized DC voltage-dominated 2nd-order GFM model and successfully conducts complex torque analysis,showing that this approach can be effectively extended to other dynamics governed by DC voltage-dominated GFM systems.Subsequently,the paper establishes a stability criterion for GFM-PV systems and proposes a parameter tuning method for DC voltage controllers that incorporates damping margin considerations.The performance of the tuned single-machine-infinite-bus GFM-PV system is validated on the RT-LAB real-time simulation platform under scenarios involving solar irradiance fluctuations and grid frequency disturbances.The proposed method proves effective in ensuring the stability of the GFM-PV system,with robust theoretical support.
基金developed in the framework of the SOLARFLESS project(TED2021-132854A-I00)REDESFUERTES project(PID2022-142416OBI00)both funded by MICIU/AEI/10.13039/501100011033 and by the European Union,NextGenerationEU/PRTR。
文摘In recent years,transmission system operators have started requesting converter-interfaced generators(CIGs)to participate in grid services such as power oscillation damping(POD).As power systems are prone to topology changes because of connection and disconnection of generators and lines,one of the most important requirements in the design of POD controller is to account for these changes.This can be done by either adjusting the controller structure during the operation or applying a fixed structure designed to address changes in the system.The fixed structure is usually preferred by transmission system operators since it is easier to determine its impact on the system.In this paper,a design procedure is proposed for network-reconfiguration-aware POD controller with fixed structure for CIG-based power plants that considers network configurations with any one line disconnected.The design procedure is based on frequency-response techniques,so it is suitable for application in CIG-based power plants,even in cases when a detailed small-signal model of the system is not available.Designs of a POD controller for the damping of critical system modes can be obtained by using active power,reactive power,or both power components simultaneously.The application to the design of a POD controller for a CIG-based power plant connected to the IEEE 39-bus system is presented as an example.Simulations performed in MATLAB and SimPowerSystems are used to validate the proposed design procedure.The validation includes an analysis of system performance with changes considered in the proposed designed procedure.Also,the system performance under unconsidered changes is examined,covering variations in load and inertia values,as well as disconnection of synchronous generators.
