Hybrid DC transmission technology is used in new energy transmission due to its advantages of large capacity and long distances.Line-commutated converter-voltage source converter-multi-terminal DC(LCC-VSC-MTDC)is one ...Hybrid DC transmission technology is used in new energy transmission due to its advantages of large capacity and long distances.Line-commutated converter-voltage source converter-multi-terminal DC(LCC-VSC-MTDC)is one of the more important development directions in future power grids.But the multi-terminal high voltage direct current system has problems of inconsistent boundary characteristics,inconsistent control,and fault response characteristics,which places higher requirements on the protection scheme.A protection scheme based on the undistorted factor is proposed to ensure the safe operation of the system.First,the inconsistent line mode voltage attenuation characteristics of different fault locations are used to construct the undistorted factor.Subsequently,the undistorted factor is used to identify fault.The advantage of this scheme is that it remains unaffected by boundary elements,control strategies,and distributed capacitance.Finally,the LCC-VSC-MTDC model verifies the correctness and superiority of the proposed protection scheme.展开更多
基金supported by the National Natural Science Foundation of China-State Grid Joint Fund for Smart Grid(No.U2066210).
文摘Hybrid DC transmission technology is used in new energy transmission due to its advantages of large capacity and long distances.Line-commutated converter-voltage source converter-multi-terminal DC(LCC-VSC-MTDC)is one of the more important development directions in future power grids.But the multi-terminal high voltage direct current system has problems of inconsistent boundary characteristics,inconsistent control,and fault response characteristics,which places higher requirements on the protection scheme.A protection scheme based on the undistorted factor is proposed to ensure the safe operation of the system.First,the inconsistent line mode voltage attenuation characteristics of different fault locations are used to construct the undistorted factor.Subsequently,the undistorted factor is used to identify fault.The advantage of this scheme is that it remains unaffected by boundary elements,control strategies,and distributed capacitance.Finally,the LCC-VSC-MTDC model verifies the correctness and superiority of the proposed protection scheme.
