Fractional order PID controller design for LFC in electric power systems using imperialist competitive algorithm

AbstractIn this paper, fractional order PID (FOPID) controller was proposed for load frequency control (LFC) in an interconnected power system. This controller had five parameters to be tuned; thus, it provided two more degrees of freedom in comparison with the conventional PID. For proper tuning of the controller parameters, imperialist competitive algorithm (ICA) was used. ICA is a new evolutionary algorithm with proved efficiency. In this study, simulation investigations were carried out on a three-area power system with different generating units. These results showed that FOPID controller was robust to the parameter changes in the power system. Also, the simulation results certified much better performance of FOPID controller for LFC in comparison with conventional PID controllers

An adaptive set-point modulation technique to enhance the performance of load frequency controllers in a multi-area power system

Parameters and configuration of power systems are continuously prone to change. This might negatively affect the performance of load frequency controllers. PI controllers are widely used for load frequency control (LFC) in power systems. Hence, enhancing the performance of these controllers is of great importance. In this paper, an adaptive set-point modulation (ASPM) method is proposed to enhance the performance of PI controllers. Simulation studies carried out on a two-area power system with different types of generating units and HVDC link prove the superiority of the proposed adaptive set-point modulation assisted proportional integral (ASPM-PI) over the conventional proportional integral (PI) and proportional integral derivative (PID) controllers. It has also been shown that the ASPM-PI controller is robust in case of power system parameters variations and change in the configuration

A novel single-end fault location method for double-circuit transmission lines

A new fault location method based on single-end measurements is proposed in this paper. The proposed method decomposes the fault location problem into two sub-problems and uses the voltage and current phasors of one of the line ends to solve the sub-problems. In the first iteration, an initial value is assumed for the fault location and then, based on the network equations, the first sub-problem calculates fault characteristics such as its voltage, current, and impedance which are fed into the second sub-problem as its inputs. Then, the second sub-problem updates the estimated fault location based on the received inputs. This approach is efficient and comprehensive method in the sense that it is not susceptible to the value of fault impedance, it is applicable for symmetrical and asymmetrical faults, transposed and untransposed lines, identical and non-identical circuits, and both short and long double circuit transmission lines. Finally, the method converges quickly in maximum three iterations although it is iterative. Numerous case studies by changing the line length, fault impedance, location of fault, line characteristics and noise level are carried out using distributed line model to verify the effectiveness of the proposed method