Sub/Super-Synchronous Oscillation Oriented Dominant Controller Parameters Stability Region Based on Gerschgorin Disk Theorem

Song Ke,Tao Lin,Baoping Chen,Yibiao Sheng,Rusi Chen,Hui Du,Qingyan Li,Shuitian Li

doi:10.3390/app11031205

Abstract

Since the development of renewable power generation, Sub/Super-Synchronous Control Interac-tion (SSCI), has attracted wide attention. Sub/super-synchronous oscillation (SSO) belongs to the category of small signal stability, and its characteristics are closely related to the operation mode and controller parameters in power grid. The operation mode of renewable power system changes frequently, a method to construct controller parameter stability region (PSR) is proposed for online assessment of the matching degree of controller parameters in power grid under current operation mode. Based on Gerschgorin disk theorem (GDT), eigenvalue distribution range of the system state matrix is estimated, thus the feasible value set of the controller parameter is deduced through small signal stability criterion. The stability margin evaluation index is proposed for guiding the prevention and control of SSO. Specifically, the preconditions of the application of the GDT on the PSR construction are discussed, and a construction method of transition matrix is proposed for the PSR construction. Furthermore, to reduce the conservativeness of PSR, an extension method for PSR is given. Finally, the validity of the proposed method is verified by a realistic benchmark. The efficiency of the proposed method is highlighted by comparing with the point-wise eigenvalue calculation of the state matrix.

Highlights

The generator shafting damage accidents in Mohave Power Plant, which were reported in the 1970s, caused people to pay attention to the Sub-synchronous Oscillation (SSO) issue, which is mainly caused by the unreasonable series compensation capacitance of the transmission lines
Based on Gerschgorin disk theorem (GDT), the eigenvalue distribution range of the system state matrix containing controller parameter variables is rapidly estimated, instead of the time-consuming direct calculation of eigenvalues, and the parameter stability region (PSR) is deduced according to the small signal stability criterion and corresponding stability constraints on the obtained eigenvalue distribution range
The transition matrix is used for the PSR construction instead of applying the system state matrix directly, to overcome its limitations

Summary

Introduction

The generator shafting damage accidents in Mohave Power Plant, which were reported in the 1970s, caused people to pay attention to the Sub-synchronous Oscillation (SSO) issue, which is mainly caused by the unreasonable series compensation capacitance of the transmission lines. The oscillation has no connection with the torsional oscillation of shafting This kind of SSO phenomenon is called Sub-synchronous Control Interaction (SSCI) [3,4,5]. The Nyquist and reactance-crossover analysis methods can provide information (e.g., frequency and damping) on the unstable oscillation modes These methods are unable to provide critical insight into the interaction phenomenon, such as the origin and path of oscillation, and the participation level of certain system components [7]. Such information is critical to properly assess the risk of SSCI and devise effective risk alleviation or mitigation strategies [9].

Methods

Results

Conclusion