Steady-state voltage stability assessment of new energy power systems with multi-quadrant power modes

Abstract

The “source–load” attributes of the nodes in a new energy power system are complex and diverse due to a large amount of new energy access. The node power (active and reactive power) in the system can offer a changing mode, which causes several serious challenges to the security of steady-state voltage stability. Aiming at the steady-state voltage stability problem in the system with multi-quadrant power modes, this paper reveals the mechanism of voltage evolution by voltage analytical expressions and the geometric characteristics of voltage components. Then, the indexes of voltage rise and drop are put forward by using a normalized voltage sensitivity. The voltage stability index is formulated based on the characteristics of voltage–power change. These indexes are used for steady-state voltage safety and stability assessment. Through the analysis of results that simulated by the IEEE-14 node power system and the coupled system in which the traditional power supply and new energy are connected to the same point of interconnection in Liaoning province, the results have proved that these indicators can be used to evaluate the steady-state voltage stability under multi-quadrant power modes. It is of great significance to guide the operation of voltage security in the power system with new energy.