Commutation failure(CF)is an inherent problem faced by line commutated converter high voltage direct current(LCC-HVDC)technology.To completely solve the problem of CF,we have proposed a novel hybrid commutated convert...Commutation failure(CF)is an inherent problem faced by line commutated converter high voltage direct current(LCC-HVDC)technology.To completely solve the problem of CF,we have proposed a novel hybrid commutated converter(HCC)technology based on reverse blocking integrated gate commutated thyristor,which can utilise two methods for commutation:enhanced grid voltage commutation and active turn-off forced com-mutation.In this paper,the topology and operating principle of HCC are proposed.Then,the control and protection strategy is designed based on the current variation trend under AC faults.To verify the effectiveness of HCC in mitigating CF,a 120-kV/360-MW HCC-HVDC model is built in PSCAD/EMTDC,adopting LCC at the rectifier side and HCC at the inverter side.Based on this model,HCC steady-state and fault transient stresses are analysed.Various AC faults are simulated and the performance of HCC-HVDC is compared with LCC-HVDC.Finally,the results show that the HCC topol-ogy and proposed control strategy can solve CF under all fault conditions with almost the same attributes as LCC,such as large capacity,low cost,low loss and high reliability,which is meaningful for the application of HCC to the HVDC transmission system.展开更多
This paper presents a fully customised integrated gate commutated thyristor(IGCT)gate driver monolithic integrated circuit(GDMIC),aiming to address the many shortcomings of traditional IGCT gate driver units composed ...This paper presents a fully customised integrated gate commutated thyristor(IGCT)gate driver monolithic integrated circuit(GDMIC),aiming to address the many shortcomings of traditional IGCT gate driver units composed of discrete components,such as the excessive number of components,low reliability,and complex development processes.The current-source driving characteristics of IGCTs pose significant technical challenges for developing fully customised integrated circuits(IC).The customised requirements of IGCT gate driver chips under various operating conditions are explored regarding functional module division,power sequencing,and chip parameter specifications.However,existing high-side(HS)driver methods exhibit limitations in functional monolithic integration and bipolar complementary metal-oxide-semiconductor compat-ibility.To address these challenges,a novel HS driving topology based on floating linear regulators is proposed.It can achieve synchronised control of multi-channel floating power transistors while supporting 100%duty cycle continuous conduction.The pro-posed GDMIC reduces the three independent HS power supplies to a single multiplexed topology,significantly decreasing circuit complexity.Experimental results validate the feasibility and performance of a 4-inch gate driver prototype based on IGCT current-source management IC,demonstrating significant advantages in reducing the number of components,enhancing device reliability,and simplifying development.The proposed GDMIC offers an innovative development path for future high-power IGCT drivers.展开更多
This paper proposes a novel AC filter system for a line commutated converter high voltage DC(LCC-HVDC)transmission system.Through the coordination of the hybrid active power filters(APF)and the existing reactive compe...This paper proposes a novel AC filter system for a line commutated converter high voltage DC(LCC-HVDC)transmission system.Through the coordination of the hybrid active power filters(APF)and the existing reactive compensation devices,the proposed filter system can not only enhance the suppression performance for LCC-HVDC harmonics,but also optimize the AC yard layout with reduced reactive power subbanks,reducing the cost of HVDC projects.The novel filter system adopts a serial passive resonance topology obtained by careful comparison of different APFs.A proper control scheme is then designed integrating the control strategy of the APF and impedance characteristics of the HVDC system,which is able to realize harmonic suppression and dynamic reactive power support simultaneously.In addition,a novel self-adaption digital low-pass filter algorithm is presented,which is used in the APF harmonic detecting step,enhancing both high precision and fast dynamic response.On the basis of a real HVDC project,the advantages of proposed filter system in harmonic suppression,reactive power regulation,and sub-banks reduction are simulated and demonstrated.展开更多
In line commutated converter based high-voltage direct current(LCC-HVDC)transmission systems,the transformer saturation can induce harmonic instability,which poses a serious threat to the safe operation of the power s...In line commutated converter based high-voltage direct current(LCC-HVDC)transmission systems,the transformer saturation can induce harmonic instability,which poses a serious threat to the safe operation of the power system.However,the nonlinear characteristics of the power grids introduced by the transformer saturation considerably limit the application of the conventional analysis methods.To address the issue,this paper derives a linear model for the transformer saturation caused by the DC current due to the converter modulation.Afterwards,the nonlinear characteristics of power grids with the transformer saturation is described by a complex valued impedance matrix.Based on the derived impedance matrix,the system harmonic stability is analyzed and the mechanism of the transformer saturation induced harmonic instability is revealed.Finally,the sensitivity analysis is conducted to find the key factors that influence the system core saturation instability.The proposed impedance model is verified by the electromagnetic transient simulation,and the simulation results corroborate the effectiveness of the proposed impedance model.Index TermsLine commutated converter based high voltage direct current(LCC-HVDC),transformer saturation,harmonic instability,impedance model.展开更多
基金National Natural Science Foundation of China-State Grid Corporation Joint Fund for Smart Grid,Grant/Award Number:U2166602。
文摘Commutation failure(CF)is an inherent problem faced by line commutated converter high voltage direct current(LCC-HVDC)technology.To completely solve the problem of CF,we have proposed a novel hybrid commutated converter(HCC)technology based on reverse blocking integrated gate commutated thyristor,which can utilise two methods for commutation:enhanced grid voltage commutation and active turn-off forced com-mutation.In this paper,the topology and operating principle of HCC are proposed.Then,the control and protection strategy is designed based on the current variation trend under AC faults.To verify the effectiveness of HCC in mitigating CF,a 120-kV/360-MW HCC-HVDC model is built in PSCAD/EMTDC,adopting LCC at the rectifier side and HCC at the inverter side.Based on this model,HCC steady-state and fault transient stresses are analysed.Various AC faults are simulated and the performance of HCC-HVDC is compared with LCC-HVDC.Finally,the results show that the HCC topol-ogy and proposed control strategy can solve CF under all fault conditions with almost the same attributes as LCC,such as large capacity,low cost,low loss and high reliability,which is meaningful for the application of HCC to the HVDC transmission system.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFB2401604The Integration Projects of National Natural Science Foundation of China-State Grid Joint Fund for Smart Grid,Grant/Award Number:U2166602National Natural Science Foundation of China,Grant/Award Number:52241701。
文摘This paper presents a fully customised integrated gate commutated thyristor(IGCT)gate driver monolithic integrated circuit(GDMIC),aiming to address the many shortcomings of traditional IGCT gate driver units composed of discrete components,such as the excessive number of components,low reliability,and complex development processes.The current-source driving characteristics of IGCTs pose significant technical challenges for developing fully customised integrated circuits(IC).The customised requirements of IGCT gate driver chips under various operating conditions are explored regarding functional module division,power sequencing,and chip parameter specifications.However,existing high-side(HS)driver methods exhibit limitations in functional monolithic integration and bipolar complementary metal-oxide-semiconductor compat-ibility.To address these challenges,a novel HS driving topology based on floating linear regulators is proposed.It can achieve synchronised control of multi-channel floating power transistors while supporting 100%duty cycle continuous conduction.The pro-posed GDMIC reduces the three independent HS power supplies to a single multiplexed topology,significantly decreasing circuit complexity.Experimental results validate the feasibility and performance of a 4-inch gate driver prototype based on IGCT current-source management IC,demonstrating significant advantages in reducing the number of components,enhancing device reliability,and simplifying development.The proposed GDMIC offers an innovative development path for future high-power IGCT drivers.
基金This work was supported in part by the National Natural Science Foundation of China(U1766210,51625702)Science and Technology Program of SGCC.
文摘This paper proposes a novel AC filter system for a line commutated converter high voltage DC(LCC-HVDC)transmission system.Through the coordination of the hybrid active power filters(APF)and the existing reactive compensation devices,the proposed filter system can not only enhance the suppression performance for LCC-HVDC harmonics,but also optimize the AC yard layout with reduced reactive power subbanks,reducing the cost of HVDC projects.The novel filter system adopts a serial passive resonance topology obtained by careful comparison of different APFs.A proper control scheme is then designed integrating the control strategy of the APF and impedance characteristics of the HVDC system,which is able to realize harmonic suppression and dynamic reactive power support simultaneously.In addition,a novel self-adaption digital low-pass filter algorithm is presented,which is used in the APF harmonic detecting step,enhancing both high precision and fast dynamic response.On the basis of a real HVDC project,the advantages of proposed filter system in harmonic suppression,reactive power regulation,and sub-banks reduction are simulated and demonstrated.
文摘In line commutated converter based high-voltage direct current(LCC-HVDC)transmission systems,the transformer saturation can induce harmonic instability,which poses a serious threat to the safe operation of the power system.However,the nonlinear characteristics of the power grids introduced by the transformer saturation considerably limit the application of the conventional analysis methods.To address the issue,this paper derives a linear model for the transformer saturation caused by the DC current due to the converter modulation.Afterwards,the nonlinear characteristics of power grids with the transformer saturation is described by a complex valued impedance matrix.Based on the derived impedance matrix,the system harmonic stability is analyzed and the mechanism of the transformer saturation induced harmonic instability is revealed.Finally,the sensitivity analysis is conducted to find the key factors that influence the system core saturation instability.The proposed impedance model is verified by the electromagnetic transient simulation,and the simulation results corroborate the effectiveness of the proposed impedance model.Index TermsLine commutated converter based high voltage direct current(LCC-HVDC),transformer saturation,harmonic instability,impedance model.
