Voltage Transient Analysis and Control Discussion of a Power Grid with High Proportion of Photovoltaic and Large-Capacity DC Receiving

With the advancement of ultra-high voltage direct current (UHVDC) transmission projects, an increasing number of regions are developing receiving-end grids that integrate both renewable energy and DC power input, significantly impacting the transient voltage stability of power systems. To investigate the effects of high-penetration distributed photovoltaic (PV) integration on the stability of modern power systems, both DC transmission and distributed PV systems are considered in the analysis to understand the new transient voltage characteristics of the receiving-end grid. In response to two key issues: insufficient reactive power support from the receiving-end AC system under high-penetration distributed PV conditions, leading to repeated commutation failures in the DC transmission system and the risk of transient voltage instability in the AC system, this paper proposes a coordinated transient voltage control method for power systems with high penetration of distributed PV and energy storage. By monitoring voltage variations at renewable energy integration points and estimating the required reactive power compensation based on the short-circuit ratios of distributed renewable energy and collection points, the method enhances transient voltage stability. Coordinated control of PV and energy storage is employed, taking into account different PV reactive power margins, to develop the reactive power compensation capability of PV inverters and ensure smooth power output, ultimately improving the transient voltage stability at grid connection points.