Design of a Damping Controller Using a Metaheuristic Algorithm for Angle Stability Improvement of an SMIB System

Low frequency oscillations in large power systems may result in system instability under large disturbances. Power system stabilisers (PSS) play an effective role in damping these low frequency oscillations by injecting a modulating signal in the excitation loop of a synchronous machine. A new metaheuristic optimisation algorithm termed the sine cosine algorithm (SCA) was proposed for optimising PSS controller parameters to obtain an optimal solution with the damping ratio as an objective function. The SCA technique was examined on a single machine infinite bus (SMIB) system under distinct loading situations and matched with a moth flame optimisation technique and evolutionary programming to design a robust controller of PSS. The simulation was accomplished using a linearised mathematical model of the SMIB. The performance of a designed lead lag-controller of PSS was demonstrated using eigenvalue analysis with simulations, showing promising results. The dynamic performance was validated with respect to the damping ratio, the eigenvalue’s location in the s-plane and rotor angle deviation response to demonstrate system stability.

Analysis of disturbance source location of direct drive wind turbine based on energy function

In order to locate the disturbance source quickly and accurately in the wind farm, taking the direct drive wind turbine as an example, using the transient energy method, firstly, the transient energy flow formula is derived according to the mathematical model of each part of the direct drive wind turbine, the energy flow power is obtained by linear fitting, and the position of the disturbance source is judged by the positive and negative energy flow power; then a single machine infinite bus system model with forced oscillation source is built on PSCAD/EMTDC simulation platform for simulation. The results show that the transient energy method can accurately locate the disturbance source of direct drive wind turbine unit.

Chaotic Power System Stabilization Based on Novel Incommensurate Fractional-Order Linear Augmentation Controller

The nonlinear dynamics of an incommensurate fractional-order single-machine infinite-bus (SMIB) power system benchmark model are explored and studied by means of modern nonlinear analysis theories, such as bifurcation, chaos, power spectral density (PSD), and bicoherence methods. The effect of incommensurate order derivatives on power system dynamics is presented. The study reveals that the power system undergoes interesting dynamics such as periodic motion, chaotic oscillations, and multistability whenever the system parameter values fall into particular ranges. A new fractional-order linear augmentation-based control scheme is applied to damp out the power system’s chaotic oscillation, change the stability of the coexisting states, and drive the system from multistability to monostability. The stability of the proposed control system is derived using Lyapunov theory. Simulation results confirmed the effectiveness and robustness of the proposed control scheme in damping power system oscillations and achieving good overall performance. The results in this paper will give a better understanding of the nonlinear dynamic behaviors of the incommensurate fractional-order SMIB power system.

Damping of inter-area oscillations by combining control strategies in hydropower plants

This paper examines how the damping capability can be improved if inter-area oscillations occur by combining control strategies in hydropower plants. First, the control challenges of hydropower plants, such as the water hammer effect, are discussed. In a single-machine infinite bus system (SMIBS), the use of a Power System Stabilizer (PSS) in the generator excitation and in the governor control path as well as the combination of both strategies are examined for their effectiveness in terms of their damping capability. In addition, these results are compared with an optimal state space controller with an observer as a damping element. The Heffron-Phillips model is the design model for the PSS as well as for the model-based controller. The verification of the damping capability through the PSS variants is evaluated by using a three-machine model in the time domain and by using modal analysis.

Application of a neuro-fuzzy controller for single machine infinite bus power system to damp low-frequency oscillations

Generally, power systems experience a variety of disturbances that can result in low frequency electromechanical oscillations. These low frequency oscillations (LFOs) take place among the rotors of synchronous generators connected to the power system. These oscillations may sustain and grow to cause system separation if no adequate damping is provided. Power system stabilizers (PSSs) are one of the alternative devices used to solve this rotor oscillation problem. The major limitation of using PSSs at the excitation system of synchronous machine is that the conventional PSS is a permanent parameter type operating under a particular system operating condition, and its parameters are acquired through trial and error. An efficient way of operating the PSS has been by designing the PSS parameters using a powerful optimization procedure. However, designing PSS damping controller is a cumbersome task as it needs a comprehensive test system modeling and a heavy computational burden on the system. In this research, a novel, model-free neuro-fuzzy controller (NFC) is designed as the LFOs’ damping controller to substitute the traditional PSS system making the power system simple without complications in PSS design and parameter optimization. The proposed controller application implements the LFOs’ control without a linearized mathematical model of the system, as such it makes the system less complex and bulky. Single machine infinite bus (SMIB) test system was simulated in SIMULINK domain with the PSSs and with the proposed controller to compare the NFC effectiveness. The simulation outcome for the eigenvalue study with NFC stabilizer yields steady eigenvalues that enhanced the damping status of the system greater than 0.1 with decreased overshoots and time to rise via the proposed NFC process than with the conventional FFA-PSS. Similarly, the generator transient reaction also presents the ω and δ based on the time to settle was improved by 64.66% and 28.78%, respectively, via the proposed NFC process than with the conventional FFA-PSS. Finally, the conventional PSS was found to be complicated in its design, parameter optimization and less effective than the proposed controller for the LFOs’ control.

Simulink Block Diagram of Sixth-order Model for Power System Dynamic Study

The order model of synchronous generator plays very important roles of determine the accuracy of power system dynamic study. This paper presents the simulation and analysis of the sixth order model of synchronous generator for power system dynamic study by using Simulink. The mathematical model of stream turbine governor and exciter are also considered in this paper. The presented method is tested on the single machine infinite bus system.