Analysis of influencing factors of short circuit ratio of multi-infeed AC/DC power systems

With the development of power grid in China, multi-infeed HV AC/DC systems are embedded into South China power grid and East China power grid. Multi-infeed short circuit ratio (MSCR) can simultaneously reflect the strength degree of HVAC systems and interaction among HVDC systems, so it is an important reference index in the construction of multi-infeed HVDC power system. The factors influencing MSCR are analyzed in depth theoretically, the influences of such factors as the electrical distance between the positions where HVDC lines connect into HVAC system, namely the mutual impedance, and network structure including network topology, line impedance, distribution of power sources on MSCR are analyzed; the variation law of MSCR is given. The conclusions are verified by calculation results of an HV AC/DC hybrid grid containing two multi-infeed HVDC systems.