Experimental Evaluation of Nonlinear Robust Control for SMES to Improve the Transient Stability of Power Systems

Abstract

This paper presents a new approach and corresponding experiments for the nonlinear robust control of a superconducting magnetic energy storage (SMES) unit to improve the transient stability of power systems. Based on the result of SMES prototype experience, a new dynamic model with disturbances of SMES is adopted, and transferred to the per unit system for simplifying the dynamic analysis and controller design. Then, feedback linearization scheme and linear control theory are applied to design a novel SMES nonlinear robust controller in a one-machine infinite bus (OMIB) power system. In order to confirm such positive effects of the proposed control strategy, experiments are carried on a laboratory setup of SMES comparing that with a conventional proportional-integral (PI) controller. The results of experiments demonstrate that the proposed nonlinear robust controller has more excellent performance to improve the transient stability of power systems than that of conventional PI controllers.Index Terms-Nonlinear robust control, power system control, power system transient stability, superconducting magnetic energy storage (SMES).

High temperature SMES for improving power system stabilities

“…Research results show that dynamics of the SMES can be simulated by the following two first order equations [11] :…”

“…From the analysis given above, the following conclusion can be obtained: If it is possible to develop a power system stability controller which can measure and compensate the unbalanced power occurred in the power system timely and accurately, the stability of power system will be greatly enhanced [11][12][13][14] .…”

“…A few results in the experiment environment were reported in recent years [11] . In this paper, supported by the Special Fund of the National Priority Basic Research of China, extensive theoretical analysis including digital simulation as well as a conduct cooling high temperature SMES prototype for power system stability enhancement is carried out.…”

Mechanism Analysis and Experimental Validation of Employing Superconducting Magnetic Energy Storage to Enhance Power System Stability

“…These references mainly focus on the experimental results and give few details about the controller design. Many advanced control techniques are also utilized to design controllers for SMES, such as the linear robust control method [14], the nonlinear robust control method [15], the extended backstepping method [16], and so on. Most of them design the SMES controllers from the viewpoint of control theory and pay little attention to the action mechanism of SMES.…”

NR-PSS (Nonlinear Robust Power System Stabilizer) for large synchronous generators and its large disturbance experiments on real time digital simulator

“…[7] proposed a decentralized nonlinear optimal excitation controller which is applied to some extend, and for the first time provided the strict mathematical proof of the optimal property of such nonlinear control solution. However, it must be pointed out that complex electric power system will inevitably be affected by various kinds of uncertainties (such as disturbances from outer circumstance measurement error, and unmodelling system dynamics) during its operation, which requires the scientific and technological workers not only to consider the nonlinear characteristics of complex power system, but also to minimize the effect of disturbances as much as possible [8][9][10][11][12][13] .…”