电力网络的谐振稳定性分析方法研究

随着电力系统电力电子化程度的不断加深,近年来出现了多起机理不明的新的振荡现象。提出了电力网络谐振稳定性的概念,试图将上述机理不明的振荡现象纳入到电力网络的谐振不稳定范畴,从而基于线性网络理论对众多复杂振荡现象进行分析,为借助数学上完全成熟的线性系统理论解决电力系统实际问题提供一条途径。围绕判断谐振稳定性的分析方法展开,通过引入电力网络的s域节点导纳矩阵,将电力网络的谐振稳定性问题归结为判断s域节点导纳矩阵行列式的零点在复平面上的分布问题。首先,理论证明了s域节点导纳矩阵行列式的零点就是系统的特征值。其次,给出了求解s域节点导纳矩阵行列式零点的实部-虚部交叉迭代法。接着,推导了特定谐振模式下的节点电压振型和参与因子矩阵,这2个指标可用来定位特定谐振模式发生的位置。最后,通过算例展示了所提方法在分析电力网络谐振稳定性方面的有效性。

Qualitative Analysis Method of Electric Network Resonance Stability

With the increasing utilization of power electronic equipment in power systems, in recent years,a number of new oscillations with unknown mechanisms have emerged. This paper puts forward the concept of the electric network resonance stability, and tries to classify the unclear reason oscillations mentioned above into the electric network resonance instability category. Thus, many complex power system oscillations can be analyzed by the linear network theory, which provides an approach to solve the actual power system problems by the mathematically mature linear system theory. The objective of this paper is to establish a method for analyzing the electric network resonance stability. By introducing the s-domain nodal admittance matrix of the electric network, this paper transforms the discrimination of the electric network resonance stability into the distribution problem in complex plane of zero point of the determinant of the s-domain nodal admittance matrix. Firstly, it is proved that the zero points of the determinant of the s-domain nodal admittance matrix are actually the eigenvalues of the system. Secondly, we use the cross iteration method of the real part and the imaginary part of the zero point to solve the zero points of the determinant of the s-domain nodal admittance matrix. Thirdly, we derive the nodal voltage mode shape and the participation factor matrix corresponding to a particular resonance mode, which can be used to locate the resonant region of this particular resonance mode in the network. Finally, we illustrate the effectiveness of the proposed method for analyzing the resonance stability of electric networks by several studied cases.