基于网络能量的新能源并网电力系统失步振荡中心影响因素及迁移特性

Out-of-step disassembly strategy of new energy power system based on network energy

随着新能源的接入,由于新能源出力随机性强,且其通过变流器并网对电力系统惯量贡献很小,新能源接入电网后系统惯量降低,使得系统失稳模式复杂多变,振荡中心发生迁移,传统基于继电保护思维的固定解列方案因此失效,极易引起失步振荡问题,将可能导致大停电事故和系统崩溃。因此,由新能源接入引起的电网振荡中心迁移问题变得尤为突出。首先,考虑新能源特性,研究新能源并网对失步振荡特征影响规律;其次,确定新能源参与失步振荡形式,分析新能源并网失稳模式变化规律和特点;最后,基于新能源电网失步振荡能量解析结果,研究新能源电网能量与振荡中心间的相关性,研究影响新能源电网振荡中心迁移的不同因素,揭示新能源电网振荡中心迁移的内在机理。

With the access of new energy,due to the strong randomness of the output of new energy and its small contribution to the inertia of the power system through the converter connection,the inertia of the system decreases after the connection of new energy to the power grid,which makes the instability mode of the system complex and changeable,and the oscillation center migrates.The traditional fixed unalignment scheme based on the relay protection thinking becomes invalid,and it is easy to cause out-of-step oscillation.Could lead to power outages and system crashes.Therefore,the migration of power grid oscillation center caused by new energy access becomes particularly prominent.Firstly,considering the characteristics of new energy,based on the network structure maintenance model of multi-machine system,an energy analysis method is established to study the influence of new energy on out-of-step oscillation characteristics.Secondly,determine the form of out-of-step oscillation of new energy,and analyze the regularities and characteristics of the instability mode of new energy connected to the grid.Finally,based on the analysis results of out-of-step oscillation energy of the new energy grid,the correlation between the energy of the new energy grid and the oscillation center is studied,and different factors affecting the migration of the oscillation center of the new energy grid are studied to reveal the internal mechanism of the migration of the oscillation center of the new energy grid.