Sliding Mode Load Frequency Control Research Articles

Non-linear sliding mode load frequency control in multi-area power system

This paper addresses non-linear sliding mode controller (SMC) with matched and unmatched uncertainties for load frequency control (LFC) application in three-area interconnected power system. In conventional LFC scheme, as the nominal operating point varies due to system uncertainties, frequency deviations cannot be minimized. These lead to degradation in the dynamic performance or even system instability. In this paper, an effective control law is proposed against matched and unmatched uncertainties.. The proposed controller has ability to vary closed-loop system damping characteristics according to uncertainties and load disturbances present in the system. The frequency deviation converges to zero with minimum undershoot/overshoot, fast settling time, significantly reduced chattering and ensures asymptotic stability. In addition, the controller is robust in the presence of parameter uncertainties and different disturbance patterns. It also guarantees high dynamic performance in the presence of governor dead band (GDB) and generation rate constraint (GRC). Simulations are performed to compare the proposed controller with linear SMC. Using proposed control strategy, undershoot/overshoot and settling time gets reduced by approximately 30% with respect to linear SMC. The computed performance indices and qualitative results establish the superiority as well as applicability of the proposed design for the LFC problem. Further, the proposed controller scheme is validated on IEEE 39 bus large power system.

The sliding mode load frequency control for hybrid power system based on disturbance observer

Abstract Penetration of wind and solar power are increasing in power systems. Intermittent characteristics of renewable sources and random load variation result in system voltage and frequency fluctuation. A load frequency control (LFC) strategy based on sliding mode control (SMC) theory and disturbance observer is proposed for the single area power system. In order to reduce the frequency deviation caused by the unmatched parameter uncertainties such as the renewable source and different load disturbance, the sliding mode load frequency controller is constructed by selecting the appropriate proportional and integral switching surface and the reaching law condition. Furthermore, the sliding mode load frequency controller is reconstructed based on the designed disturbance observer (DOB) to improve the dynamic performance and suppress the chattering. The proposed method is compared with the conventional sliding mode LFC and the robust adaptive LFC (RALFC) by using the matlab software, the simulation results show that the designed LFC has faster response speed and better robust performance.

Decentralized Sliding Mode Load Frequency Control for Multi-Area Power Systems

Based on the decentralized sliding mode control, a load frequency controller is designed in this paper for multi-area interconnected power systems with matching and unmatched uncertainties. The proportional and integral switching surface is constructed for each area to improve system dynamic performance in reaching intervals. The robust controller is proposed by the reaching law method to assure that frequency fluctuation converges to zero after a load and operation point variation. A three-area interconnected power system is studied to illustrate the effectiveness of the proposed decentralized sliding mode control scheme.

Fuzzy Sliding Mode Load Frequency Control of Multiarea Interconnected Power Systems

A fuzzy sliding mode load frequency control method for multiarea interconnected power systems is proposed in this paper. The method using sliding mode surface with integral model makes the systems can reach on switching surface from any initial state. After reaching on switching surface, systems are controlled by PI controller based on new area control error. The coefficient of switching control is adjusted by fuzzy control model automatically. When considering generation rate constraint and the governor deadband nonlinearity, the proposed control method can make systems have good dynamic performance. The design of controller in each area only considers the state information of itself area, and doesn't consider the one of the others, thus make decentrilised control be easier. Simulation results show that the proposed method is simple, effective, and can ensure that the overall system is asymptotically stable.