Subsequent commutation failure(SCF)can be easily generated during the first commutation failure(CF)recovery process in a line-commutated converter-based high voltage direct-current system.SCF poses a significant threa...Subsequent commutation failure(SCF)can be easily generated during the first commutation failure(CF)recovery process in a line-commutated converter-based high voltage direct-current system.SCF poses a significant threat to the safe and stable operation of power systems,and accurate prediction of CF is thus important.However,SCF is affected by the operating characteristics of the main circuit and the coupling effects of sequential control response in the inverter station.These are difficult to predict accurately.In this paper,a new SCF prediction method considering the control response is proposed based on the physical principle of SCF.The time sequence and switching conditions of the controllers at different stages of the first CF recovery process are described,and the corresponding equations of commutation voltage affected by different controllers are derived.The calculation method of the SCF threshold voltage is proposed,and the prediction method is established.Simulations show that the proposed method can predict SCF accurately and provide useful tools to suppress SCF.展开更多
For the safe and fast recovery of line commutated converter based high-voltage direct current(LCC-HVDC)transmission systems after faults,a DC current order optimization based strategy is proposed.Considering the const...For the safe and fast recovery of line commutated converter based high-voltage direct current(LCC-HVDC)transmission systems after faults,a DC current order optimization based strategy is proposed.Considering the constraint of electric and control quantities,the DC current order with the maximum active power transfer is calculated by Thevenin equivalent parameters(TEPs)and quasi-state equations of LCC-HVDC transmission systems.Meanwhile,to mitigate the subsequent commutation failures(SCFs)that may come with the fault recovery process,the maximum DC current order that avoids SCFs is calculated through imaginary commutation process.Finally,the minimum value of the two DC current orders is sent to the control system.Simulation results based on PSCAD/EMTDC show that the proposed strategy mitigates SCFs effectively and exhibits good performance in recovery.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant(51877018).
文摘Subsequent commutation failure(SCF)can be easily generated during the first commutation failure(CF)recovery process in a line-commutated converter-based high voltage direct-current system.SCF poses a significant threat to the safe and stable operation of power systems,and accurate prediction of CF is thus important.However,SCF is affected by the operating characteristics of the main circuit and the coupling effects of sequential control response in the inverter station.These are difficult to predict accurately.In this paper,a new SCF prediction method considering the control response is proposed based on the physical principle of SCF.The time sequence and switching conditions of the controllers at different stages of the first CF recovery process are described,and the corresponding equations of commutation voltage affected by different controllers are derived.The calculation method of the SCF threshold voltage is proposed,and the prediction method is established.Simulations show that the proposed method can predict SCF accurately and provide useful tools to suppress SCF.
基金supported by the National Key Research and Development Program of China(No.2021YFB2400902)the Innovation Young Talents Program of Changsha Science and Technology Bureau(No.kq2107005)the Postgraduate Scientific Research Innovation Project of Hunan Province(No.QL20210101).
文摘For the safe and fast recovery of line commutated converter based high-voltage direct current(LCC-HVDC)transmission systems after faults,a DC current order optimization based strategy is proposed.Considering the constraint of electric and control quantities,the DC current order with the maximum active power transfer is calculated by Thevenin equivalent parameters(TEPs)and quasi-state equations of LCC-HVDC transmission systems.Meanwhile,to mitigate the subsequent commutation failures(SCFs)that may come with the fault recovery process,the maximum DC current order that avoids SCFs is calculated through imaginary commutation process.Finally,the minimum value of the two DC current orders is sent to the control system.Simulation results based on PSCAD/EMTDC show that the proposed strategy mitigates SCFs effectively and exhibits good performance in recovery.
