Voltage source converter based high voltage direct current(VSC-HVDC)can participate in voltage regulation by flexible control to help maintain the voltage stability of the power grid.In order to quantitatively evaluat...Voltage source converter based high voltage direct current(VSC-HVDC)can participate in voltage regulation by flexible control to help maintain the voltage stability of the power grid.In order to quantitatively evaluate its influence on the voltage interaction between VSC-HVDC and line commutated converter based high voltage direct current(LCC-HVDC),this paper proposes a hybrid multi-infeed interaction factor(HMIIF)calculation method considering the voltage regulation control characteristics of VSC-HVDC.Firstly,for a hybrid multi-infeed high voltage direct current system,an additional equivalent operating admittance matrix is constructed to characterize HVDC equipment characteristics under small disturbance.Secondly,based on the characteristic curve between the reactive power and the voltage of a certain VSC-HVDC project,the additional equivalent operating admittance of VSC-HVDC is derived.The additional equivalent operating admittance matrix calculation method is proposed.Thirdly,the equivalent bus impedance matrix is obtained by modifying the alternating current(AC)system admittance matrix with the additional equivalent operating admittance matrix.On this basis,the HMIIF calculation method based on the equivalent bus impedance ratio is proposed.Finally,the effectiveness of the proposed method is verified in a hybrid dual-infeed high voltage direct current system constructed in Power Systems Computer Aided Design(PSCAD),and the influence of voltage regulation control on HMIIF is analyzed.展开更多
The close proximity and the necessity of coordination between multiple high-voltage direct currents(HVDCs)raise the issue of grid partitioning in multi-infeed HVDC systems.A multi-objective partition strategy is propo...The close proximity and the necessity of coordination between multiple high-voltage direct currents(HVDCs)raise the issue of grid partitioning in multi-infeed HVDC systems.A multi-objective partition strategy is proposed in this paper.Several types of relationships to be coordinated and complemented are analyzed and formulated using quantitative indices.According to the graph theory,the HVDC partition is transformed into a graph-cut problem and solved via the spectral clustering algorithm.Finally,the proposed method is validated for a practical multi-HVDC grid,confirming its feasibility and effectiveness.展开更多
In multi-infeed HVDC system, the interactions and influences between DC systems AC systems are complex as the electrical distances among DC converter stations which are relatively short. Multi-infeed interaction facto...In multi-infeed HVDC system, the interactions and influences between DC systems AC systems are complex as the electrical distances among DC converter stations which are relatively short. Multi-infeed interaction factor (MIIF) can effectively reflect the interaction among DC systems. The paper theoretically analyzes the impact factors of MIIF like the electrical distances between two DC converter stations and the equivalent impedance of the receiving end AC system. By applying the Kirchhoff’s current law on the inverter AC bus, the paper deduces the analytical expressions for MIIF. From the expression, it is clear how the equivalent impedance of AC system and coupling impedance can affect MIIF. PSCAD simulations validate the effectiveness and the correctness of the proposed expression and some useful conclusions are drawn.展开更多
提出一种适用于V2G(Vehicle tǒgrid,VZG)和电网-蓄电池储能等系统的单级双向隔离AC-DC变换器。该变换器可实现高效率、高功率密度,及能量双向传输。该文介绍该变换器的工作原理、功率传输特性,分析并设计软开关ZVS(zero voltage switch...提出一种适用于V2G(Vehicle tǒgrid,VZG)和电网-蓄电池储能等系统的单级双向隔离AC-DC变换器。该变换器可实现高效率、高功率密度,及能量双向传输。该文介绍该变换器的工作原理、功率传输特性,分析并设计软开关ZVS(zero voltage switching,ZVS)的实现,最终可在宽增益范围和全负载情况下实现软开关,并制作一台500 W的实验样机进行验证。展开更多
针对双向隔离型AC-DC矩阵变换器,文中提出一种软开关复合调制策略,其中,前级3-1矩阵式变换电路采用对称双线电压调制法,以提高电压传输比;后级全桥电路采用互补控制,简单易实现;前后级电路之间进行移相控制。通过协调安排前后级脉冲宽...针对双向隔离型AC-DC矩阵变换器,文中提出一种软开关复合调制策略,其中,前级3-1矩阵式变换电路采用对称双线电压调制法,以提高电压传输比;后级全桥电路采用互补控制,简单易实现;前后级电路之间进行移相控制。通过协调安排前后级脉冲宽度分布,使得矩阵变换器中的双向开关在采用简单的两步换流时,可保证全部开关器件实现零电压开关(zero voltage switching,ZVS)换流。仿真和实验结果表明,网侧电流三相平衡正弦,相电流谐波畸变率小于3%,功率因数接近于1,输出电压和电流为稳定直流,电压电流纹波小,变换器中的双向开关和普通开关器件均能实现ZVS换流。在宽负载范围(10%~100%)内效率均保持在94.5%以上,最高效率可达97.74%。因此,采用提出的调制策略可实现双向隔离型AC-DC矩阵变换器功率的稳定传输,在保证良好的输入输出性能的同时,实现了开关器件的零电压换流,具有高效率。展开更多
基金supported by the Technology Project of the State Grid Corporation Headquarters Management(Contract No.5100-202158467A-0-0-00).
文摘Voltage source converter based high voltage direct current(VSC-HVDC)can participate in voltage regulation by flexible control to help maintain the voltage stability of the power grid.In order to quantitatively evaluate its influence on the voltage interaction between VSC-HVDC and line commutated converter based high voltage direct current(LCC-HVDC),this paper proposes a hybrid multi-infeed interaction factor(HMIIF)calculation method considering the voltage regulation control characteristics of VSC-HVDC.Firstly,for a hybrid multi-infeed high voltage direct current system,an additional equivalent operating admittance matrix is constructed to characterize HVDC equipment characteristics under small disturbance.Secondly,based on the characteristic curve between the reactive power and the voltage of a certain VSC-HVDC project,the additional equivalent operating admittance of VSC-HVDC is derived.The additional equivalent operating admittance matrix calculation method is proposed.Thirdly,the equivalent bus impedance matrix is obtained by modifying the alternating current(AC)system admittance matrix with the additional equivalent operating admittance matrix.On this basis,the HMIIF calculation method based on the equivalent bus impedance ratio is proposed.Finally,the effectiveness of the proposed method is verified in a hybrid dual-infeed high voltage direct current system constructed in Power Systems Computer Aided Design(PSCAD),and the influence of voltage regulation control on HMIIF is analyzed.
基金supported by the Science and Technology Project of State Grid Corporation of China:“Control Strategy Optimization Technology for Large-Scale Photovoltaic Power Generation on the Sending-end and Receiving-end of DC Power System”(4000-201934198A-0-0-00)
文摘The close proximity and the necessity of coordination between multiple high-voltage direct currents(HVDCs)raise the issue of grid partitioning in multi-infeed HVDC systems.A multi-objective partition strategy is proposed in this paper.Several types of relationships to be coordinated and complemented are analyzed and formulated using quantitative indices.According to the graph theory,the HVDC partition is transformed into a graph-cut problem and solved via the spectral clustering algorithm.Finally,the proposed method is validated for a practical multi-HVDC grid,confirming its feasibility and effectiveness.
文摘In multi-infeed HVDC system, the interactions and influences between DC systems AC systems are complex as the electrical distances among DC converter stations which are relatively short. Multi-infeed interaction factor (MIIF) can effectively reflect the interaction among DC systems. The paper theoretically analyzes the impact factors of MIIF like the electrical distances between two DC converter stations and the equivalent impedance of the receiving end AC system. By applying the Kirchhoff’s current law on the inverter AC bus, the paper deduces the analytical expressions for MIIF. From the expression, it is clear how the equivalent impedance of AC system and coupling impedance can affect MIIF. PSCAD simulations validate the effectiveness and the correctness of the proposed expression and some useful conclusions are drawn.
文摘提出一种适用于V2G(Vehicle tǒgrid,VZG)和电网-蓄电池储能等系统的单级双向隔离AC-DC变换器。该变换器可实现高效率、高功率密度,及能量双向传输。该文介绍该变换器的工作原理、功率传输特性,分析并设计软开关ZVS(zero voltage switching,ZVS)的实现,最终可在宽增益范围和全负载情况下实现软开关,并制作一台500 W的实验样机进行验证。
文摘针对双向隔离型AC-DC矩阵变换器,文中提出一种软开关复合调制策略,其中,前级3-1矩阵式变换电路采用对称双线电压调制法,以提高电压传输比;后级全桥电路采用互补控制,简单易实现;前后级电路之间进行移相控制。通过协调安排前后级脉冲宽度分布,使得矩阵变换器中的双向开关在采用简单的两步换流时,可保证全部开关器件实现零电压开关(zero voltage switching,ZVS)换流。仿真和实验结果表明,网侧电流三相平衡正弦,相电流谐波畸变率小于3%,功率因数接近于1,输出电压和电流为稳定直流,电压电流纹波小,变换器中的双向开关和普通开关器件均能实现ZVS换流。在宽负载范围(10%~100%)内效率均保持在94.5%以上,最高效率可达97.74%。因此,采用提出的调制策略可实现双向隔离型AC-DC矩阵变换器功率的稳定传输,在保证良好的输入输出性能的同时,实现了开关器件的零电压换流,具有高效率。
