Research on Multi-Level Transmission Sections Stability Limits of Northwest China Power Grid Based on Low Voltage Impact Analysis

With the advancement of the new power system and accelerated development of renewable energy, its randomness, intermittency, its randomness, intermittence and volatility will lead to the complexity and variability of power system operation mode. At the same time, with the rapid development of UHVDC and the continuous improvement of AC/DC grid coupling, the traditional grid pre-control stability limits method is difficult to adapt to the complex and changeable characteristics of the new power system mode and the demand for new energy transmission and accommodation. Therefore, it is urgent to carry out multilevel transmission sections stability limit modeling research. This paper, taking the XJ outgoing section, HeY section and HX section as the research object, based on the simplified model of Northwest China Power Grid, clarifies the relationship between the dynamic reactive power characteristics of lines and new energy and the initial power of the section, and then derives mathematical representations of the initial power of section and the voltage fluctuation of the nodes, which provides a simplified analytical method for the grid dispatching and operation.