An improvement of the transient voltage assessment method of the DC receiving-end considering access of high-proportion photovoltaic

High-proportion photovoltaic feeding into the DC (Direct Current) receiving end grid makes it very easy to cause DC phase change failure, or even DC blocking and other faults after disturbances occur at the receiving terminal, and its transient voltage stability problem is very prominent, so it is of great significance to quantitatively evaluate the transient voltage stability of DC receiving terminal system. Firstly, we analyze the complex transient characteristics of the DC receiving end after large-scale new energy feed-in, then based on the existing multibinary table criterion and the transient characteristics of the DC system, and taking into account the transient voltage changes brought by the new energy feed-in, we proposed a three-stage transient voltage assessment method with transient fast recovery, transient slow recovery and transient overvoltage using the idea of assigning different weights to the different transient phases to achieve the assessment of the transient voltage stability. Finally, the applicability of the three-stage transient voltage assessment method to DC system is verified based on the PV receiving end grid with different penetration rates and the receiving end system after the improvement of PV reactive power compensation capacity, and the results show that the proposed method can realize the effective assessment of transient voltage stability of DC receiving end system with large-scale new energy.