Abstract: The dynamic equivalent calculation of the existing line commutated converter based HVDC (LCC-HVDC) transmission system depends on the synchronous real-time measurement of the voltage at the sending and receiving ends, and it is impossible to realize the single-end transient equivalent calculation of the transmission system through LCC-HVDC. Based on the dynamic phasor equivalent calculation framework of the DC system, the paper proposes an equivalent calculation scheme of the DC transmission system through LCC-HVDC based on the single-terminal AC voltage information of the inverter side only, demonstrates the feasibility of the hybrid equivalent calculation framework of the quasi-steady state model of the rectifier side and the dynamic phasor model of the inverter side, solves the key problems such as accurate identification of commutation failure, as well as compares and analyzes the multi-scenario faults through simulation. It is proved that the proposed calculation framework can achieve accurate real-time calculation of the response of LCC-HVDC transmission system under the large transient disturbance of AC line fault at the receiving end when the information of the AC system at the sending end is missing.