Abstract
The existing spectral discretization-based methods (SDMs) are capable of accurately computing critical eigenvalues of large power systems when time delays in wide-area damping control loops are considered. However, SDMs suffer from huge dimension of the discretized matrices of spectral operators, which is usually dozens of times of actual system states. To resolve the problem, an idea of partial spectral discretization (PSD) is proposed in this paper where only the retarded state variables instead of all system states are discretized. Following the PSD idea, a partial and explicit infinitesimal generator discretization (PEIGD) method is presented for highly efficient eigen-analysis of large closed-loop delayed cyber-physical power system (DCPPS). In contrast to the original EIGD method, the order of the resultant discretized matrix of the infinitesimal generator is greatly reduced and close to the number of actual state variables. The computational burden of PEIGD can be an order of magnitude less than that of EIGD and nearly the same as eigen-analysis of a system without time delay. Moreover, PEIGD is endowed with exactly the same accuracy as EIGD in capturing critical oscillation modes. Both theoretical analyses and intensive tests on the 16-generator 68-bus test system as well as a 516-bus and a 33028-bus real-life large power systems verify the accuracy and efficiency of the presented method.
Highlights
R EAL-TIME and synchronized dynamic information provided by WAMS facilitates analysis, detection and location of oscillations in power systems
With the aim of capturing critical oscillation modes of delayed cyber-physical power system (DCPPS), partial and explicit infinitesimal generator discretization (PEIGD) is efficiently implemented by synthesizing several key techniques
1) High Efficiency of PEIGD in Analyzing Large DCPPS is Achieved by Low Order of AN : Compared with EIGD, the order reduction made by PEIGD is N n1
Summary
R EAL-TIME and synchronized dynamic information provided by WAMS facilitates analysis, detection and location of oscillations (both free and forced) in power systems. In [19], [20], the method was employed to analyze the small signal stability of microgrids where the effects of communication delays were considered As another milestone in eigen-analysis of the closed-loop DCPPS, an EIGD method was presented in [21], [22] to efficiently compute the electromechanical oscillation modes of real-life large DCPPS by executing the unique pseudo-spectral discretized scheme [23]. A common feature of SDMs is the huge dimension of the discretized matrices approximating the infinitesimal generator and the solution operator of DCPPS, which is generally dozens of times of the number of actual system state variables. Instead of discretization of all system states, only the retarded ones are discretized Following this idea, a PEIGD-based eigen-analysis method is presented in this paper.
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