计及大规模电网时变参数的低频振荡多重扰动源定位研究

Locating of disturbance source of low-frequency oscillation is a difficult problem and a hot topic for the researchers in power systems. Especially, with the rapid expansion of power grid scale as well as integration of nonlinear loads and volatility power sources, the time-varying characteristics of the power grid's parameters become more significant, which will increase the range of oscillation mode and the probability of mutual excitation among oscillation modes, and also let dynamic information of low-frequency oscillation couple together so as to bring difficulties in disturbance source localization especially when multiple disturbance sources exist simultaneously. In order to overcome the difficulty mentioned above, this project aims to propose novel approaches considering the time-varying parameters of power grids and time-frequency-spatial distribution of dynamic characteristics of power oscillation to locate the multiple disturbance sources in large scale power grids based on dynamic synchronized phasor measurement. By establishing the propagation model of low-frequency oscillation with time-varying parameters of power grids, designing self-adapt synchrophasor measurement algorithms for low-frequency oscillation condition, analyzing the penetration-and-propagation mechanism of dynamic information excited by multiple disturbance sources, studying distortion characteristics under the dissemination process of low-frequency oscillation in the time domain, frequency domain and space distribution, the law of inter-excitation of adjacent oscillation mode with time-varying parameters of power grids can be revealed accordingly and the feature extraction method considering coupling dynamic information could be proposed. At the end, the accurate and real-time disturbance locating approach could be given by establishing dynamic credible probability model based on information fusion theory. The project aims to provide the theoretical basis to suppress and prevent the low-frequency oscillation timely and give an important theoretical and technical support for the security and stability operation of power systems and enhancement of power quality in power systems.

电网低频振荡扰动源定位是难题和热点。特别是随着电网规模扩大、非线性负荷和波动性电源接入，电网参数时变特征越发显著，导致振荡模式增多、模式相互激发几率增大，且振荡传播的动态信息相互耦合，使扰动源尤其是多重扰动源定位愈加困难。为此，本项目提出计及大规模电网时变参数影响和低频振荡"时域-频域-空间"分布特性的多重扰动源定位新方法。在建立输电网时变分布参数低频振荡传播模型的基础上，通过设计低频振荡工况下的自适应动态相量测量算法，分析多重扰动源所激发动态信息的相互渗透和传播机理，掌握低频振荡在传播过程中在时域、频域和空间上的畸变特征，揭示相邻振荡模式在电网时变参数下的交互激发规律、提出耦合动态信息的特征提取方法，最后利用信息融合理论建立动态可信概率模型来实现对多重扰动源的准确实时定位。项目旨在为抑制和快速平息电网低频振荡提供理论依据，并为电网电能质量水平的提高和系统稳定运行的实现提供理论和技术支撑。

随着全国电网区域互联规模的不断扩大，非线性负荷和波动性电源接入，区域间的低频振荡现象日益频繁，已逐渐成为威胁互联电网安全稳定运行的突出问题。低频振荡的产生，关键在于系统存在扰动源。因此，在建立输电网时变分布参数低频振荡传播模型的基础上，揭示低频振荡现象的产生、传播、渗透机理，进而研究具有实时、准确、可靠的扰动源定位方法对有效抑制和快速平息系统振荡具有重要意义。.本项目根据电网组成部分的运行特性及相互作用机理，综合考虑广域动态相量信息分析在不同拓扑结构、系统配置和运行环境下电网各部分的分布参数随时间的变化规律。首先，基于MATLAB 和EMTDC/PSCAD 平台建立起时变分布参数的电网动态等值数学/仿真模型；基于电网中各种运行模式下的各类扰动源等值模型，建立了各类扰动源的数学/仿真模型。其次，在低频振荡工况下，通过自适应调整数据窗、动态特性量化指标来修正时变参数估计，研究符合现有PMU 架构并适合低频振荡环境的动态相量测量算法。最后，基于低频振荡扰动源等值模型，研究扰动源动态信息的产生、传播和耦合渗透机理，分析提取低频振荡的时频空间分布特性，得到动态特性的时频空间分布规律，进而提出一种基于动态频率相位测量的低频振荡扰动源定位方法，得到扰动源的准确位置分布。.本项目通过对低频振荡模式下等值模型、分布特性、传播规律、扰动源定位等方面的研究，为未来低频振荡的抑制平息提供了重要的理论支撑和技术参考。.