In traditional hybrid DC circuit breakers(HCBs)schemes,complex equipment is usually required to ensure current commutation from mechanical to semiconductor switches,which cause not only additional construction costs a...In traditional hybrid DC circuit breakers(HCBs)schemes,complex equipment is usually required to ensure current commutation from mechanical to semiconductor switches,which cause not only additional construction costs and volume but also additional losses and maintenance work.Different from this condition,a low-loss and compact HCB scheme that does not use separate current commutation equipment is proposed in this study.By rationally using the charge and discharge of the snubber capacitor,the self-commutated semiconductor switch(SCS)module can integrate both the current commutation and shutdown functions,thereby greatly reducing cost and volume.The working process is discussed and analyzed in detail,and then a 10-kA prototype is developed and tested,which verifies the feasibility and effectiveness of the proposed scheme.Index Terms-HVDC circuit breakers,hybrid DC circuit breakers(HCBs),self-commutated semiconductor switch(SCS).展开更多
The synchronizing torque of a power system may be weakened by increasing installation of static power converters accompanied by renewable energy resources because they used to trade their favorable active power by syn...The synchronizing torque of a power system may be weakened by increasing installation of static power converters accompanied by renewable energy resources because they used to trade their favorable active power by synchronizing their output voltage with the one at the point of common coupling. In the circumstances, a concept of Virtual Synchronous Machine (VSM) is proposed, where the self-commutated power converters are emulating synchronous generators. This paper describes a converter control to contribute to enhancing the synchronizing torque. The proposed control is similar to the VSM but it simply realizes active power trades among power generation units including converter-based generators by modulating phase angles of their output voltages. Therefore, it can provide an effective support to regulate the system frequency where the total rated power of the converter-based generators increases as much as the one of conventional rotating generators like a microgrid. This paper especially focuses on its robustness where the number of converter-based generators is increased or they are dispersed in the power network. The effectiveness is verified by simulation study based on instantaneous values.展开更多
基金supported by the National Natural Science Foundation of China(No.52107004)the China Postdoctoral Science Foundation(No.2020M680484 and No.2021T140201)the Fundamental Research Funds for the Central Universities(No.2021MS003)。
文摘In traditional hybrid DC circuit breakers(HCBs)schemes,complex equipment is usually required to ensure current commutation from mechanical to semiconductor switches,which cause not only additional construction costs and volume but also additional losses and maintenance work.Different from this condition,a low-loss and compact HCB scheme that does not use separate current commutation equipment is proposed in this study.By rationally using the charge and discharge of the snubber capacitor,the self-commutated semiconductor switch(SCS)module can integrate both the current commutation and shutdown functions,thereby greatly reducing cost and volume.The working process is discussed and analyzed in detail,and then a 10-kA prototype is developed and tested,which verifies the feasibility and effectiveness of the proposed scheme.Index Terms-HVDC circuit breakers,hybrid DC circuit breakers(HCBs),self-commutated semiconductor switch(SCS).
文摘The synchronizing torque of a power system may be weakened by increasing installation of static power converters accompanied by renewable energy resources because they used to trade their favorable active power by synchronizing their output voltage with the one at the point of common coupling. In the circumstances, a concept of Virtual Synchronous Machine (VSM) is proposed, where the self-commutated power converters are emulating synchronous generators. This paper describes a converter control to contribute to enhancing the synchronizing torque. The proposed control is similar to the VSM but it simply realizes active power trades among power generation units including converter-based generators by modulating phase angles of their output voltages. Therefore, it can provide an effective support to regulate the system frequency where the total rated power of the converter-based generators increases as much as the one of conventional rotating generators like a microgrid. This paper especially focuses on its robustness where the number of converter-based generators is increased or they are dispersed in the power network. The effectiveness is verified by simulation study based on instantaneous values.
