An Efficient Rapid Method for Generators Coherency Identification in Large Power Systems

Abstract

With steadily increasing interest in enhancing large power systems' transient stability, generator coherency identification has become critical for the dynamic equivalents, controlledislanding, and wide-area control of these systems. This paper presents an approach based on two classical and powerful techniques. The proposed method comprises the slow coherency method followed by the time-domain-based simulation of transient stability to identify the coherent groups of generators. In this regard, various operating conditions of the system are considered to obtain the updated coherency information between groups of generators by analyzing the chosen generator rotor angle. The proposed approach's merits are tested on the New England IEEE 39-Bus and modified IEEE 118-Bus test systems in the PowerFactory software tools through Python. Corresponding simulation results validate the proposed paradigm's effectiveness by enhancing the transient stability speed of a large power system without decreasing its coherency behavior accuracy. It is also observed that the proposed scheme tends to be more consistent in determining the coherent groups of generators in the presence of disturbances and different operational conditions.

Voltage angle‐based coherency identification in power system

“…Upon literature survey, coherency detection has been found to be used in various stability studies like developing a control strategy for mitigating inter-area oscillation [4], and system model reduction to assist in transient stability analysis [5,6]. Conventionally, coherency identification was model-based methods based on the slow-coherency method [7][8][9]. Modelbased methods are implemented by performing power system linearization around the operation point.…”

“…However, any change in this operation point due to variations in the network configuration will lead to invalid linearization, causing inaccurate coherency results. Furthermore, it is time-consuming to obtain the system state matrix [2] and requires extensive offline analytical studies [4,6,7].…”

Application of Improved Quasi-Affine Transformation Evolutionary Algorithm in Power System Stabilizer Optimization

“…In recent years, the continuous operation of large generator sets and the large-scale use of high-gain and fast excitation system have improved the transient level of the system, but also caused the problem of low frequency oscillation of the power system due to insufficient damping, which has increasingly become an important factor restricting the overall interconnection of the power grid [1][2][3]. Power system stabilizer (PSS) can not only offset the negative damping torque generated by the regulator, but also provide additional positive damping for the system, which is the most efficient and economical measure to suppress the low-frequency oscillation of the power system [4][5]. Especially in the context of large power grid, PSS has been widely used.…”

“…(5) Evaluate the group according to the objective function based on characteristic value. (6) Use the improved QUasi-Affine Transformation Evolutionary algorithm to continuously update and search, generate offspring populations, and update next-generation candidate solutions.…”

Application of Improved Quasi-Affine Transformation Evolutionary Algorithm in Power System Stabilizer Optimization

“…In recent years, the continuous operation of large generator sets and the large-scale use of high-gain and fast excitation systems have improved the transient level of the system, but also caused the problem of low frequency oscillation of the power system due to insufficient damping, which has increasingly become an important factor restricting the overall interconnection of the power grid [1][2][3]. A power system stabilizer (PSS) can not only offset the negative damping torque generated by the regulator, but also provide additional positive damping for the system, which is the most efficient and economical measure for suppressing the low-frequency oscillation of the power system [4,5]. Especially in the context of a large power grid, PSS has been widely used.…”