A method and system for analyzing static voltage stability of a receiving-end power grid of an LCC-HVDC

Abstract

This invention discloses a method and system for analyzing the static voltage stability of an LCC-HVDC receiving-end power grid. The method employed is as follows: based on a quasi-steady-state mathematical model of the AC / DC system, the power balance equation and the AC system power flow equation are simultaneously established to obtain the power-voltage relationship equation; partial derivatives of the power-voltage relationship equation with respect to voltage and reactive power are obtained to determine the voltage sensitivity to reactive power changes, i.e., the voltage stability index VSI; to describe the voltage stability at the critical steady state of the system, the curve of DC power versus DC current is set to its highest point, and the effective short-circuit ratio at this point is defined as the generalized critical effective short-circuit ratio (GCESCR); based on the GCESCR, the impact of different control modes of the asynchronous power supply on static voltage stability is analyzed. This invention can more accurately describe the voltage support strength of the LCC-HVDC receiving-end AC power grid after the asynchronous power supply is connected.

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