Small Signal Stability Improvement Research Articles

RETRACTED: Improvement of transient and small signal stability in micro grid by hybrid technique with virtual synchronous generator control scheme

In this article, a hybrid technique is proposed for improving the transient and small signal response in micro grid using virtual inertia. The proposed hybrid technique is the combined execution of both the emperor penguin optimizer (EPO) and butterfly optimization algorithm (BOA), and hence it is called EPOBOA technique. The major objective of the EPOBOA technique is to “optimize the control parameters to regulate the changes occurred in the grid parameter such as voltage and frequency based on the variations of inertia”. Here, the EPO is executed to modify the parameters of virtual synchronous generator units to achieve the objective function. The searching behaviour of the EPO is adapted by using the hunting behaviour of BOA. The proposed technique is executed in MATLAB/Simulink work site, and the experimental results are analyzed under three test cases: normal condition, irradiation change condition, and load change condition. The performance of the proposed technique is compared with different existing techniques and the calculated frequency deviation index of the proposed technique in all the cases is 0.0051, 0.0045, and 0.0047 and found to be very optimal compared with existing methods. Overall, the experimental outcomes show that the proposed EPOBOA method is more efficient and confirm its ability to solve the issues.

Design of a Damping Controller Using the SCA Optimization Technique for the Improvement of Small Signal Stability of a Single Machine Connected to an Infinite Bus System

This paper discusses the use of a stochastic metaheuristic population-based optimization algorithm known as the sine cosine algorithm (SCA) to design the parameters of a power system stabilizer (PSS) for damping electromechanical oscillations in a single machine connected to a large power system. The design of the PSS parameters was formulated as an optimization problem to minimize the objective function value. The SCA was used to obtain the best values of the PSS parameters under the objective function. Simulation was carried out by a linearized power system model. The lead lag controller was used as the PSS structure and the results from that were compared with those obtained by moth flame optimization and evolutionary programming. The results showed that the SCA is more effective than are the other techniques in exploration and exploitation to tune the PSS parameters and enhance the power system stability by damping oscillations in a range of loading conditions.

Improvement of Small Signal Stability of SMIB System with Optimized Power System Stabilizer

As electrical power system is a complex system, there are more chances of stability issues may arise. One of the stability issues is Low Frequency Oscillations (LFOs) which makes the system unstable. As these oscillations are having low frequency i.e. large time constant with slowly increasing magnitude, they are referred to small signal stability. The main reason of these oscillations is due to lack of sufficient damping torque. Automatic Voltage Regulator (AVR) action in generator is providing sufficient synchronizing torque for system stability. This is possible with high gain and low time constant AVR which results in reduction of damping torque. Power System Stabilizer (PSS) is used together with AVR for providing necessary damping torque to minimize the LFOs. For effective damping, the PSS performance is improved by optimizing its parameters. In this paper, Single Machine Infinite Bus (SMIB) system is considered for studying the effect of LFOs. The SMIB system is simulated for a step disturbance in reference voltage and the results are carried out for different optimizing techniques Particle Swarm Optimization (PSO), Cat Swarm Optimization (CSO), Teaching and Learning based Optimization (TLBO).

Transient and small signal stability improvement in microgrid using AWOALO with virtual synchronous generator control scheme

A hybrid technique for improving the transient and small signal stability in microgrid (MG) using virtual inertia is discussed at these manuscripts. The established hybrid method denotes combined performance of both Whale Optimization Algorithm (WOA) and Ant Lion Optimization (ALO) algorithm it is named as AWOALO technique. The purpose of AWOALO technique is to optimize the control parameters for regulate the changes occurred in the grid parameter such as voltage as well as frequency depend on variations of inertia. AWOALO technique is performed to optimally adjust the parameters to have a smooth transition behind a change or disturbance. Here, the Virtual Synchronous Generator denotes control method to inverter depend on generator units, which uses a synchronous generator (SG) enhance system stability. WOA is performed to adjust the parameters of VSG units to attain the objective function. The searching behaviour of WOA is modified by the hunting behaviour of ALO. This hunting behaviour of ALO is used to achieve the objective function with less computational complexity. The AWOALO technique with the VSG control scheme ensures the smooth response, accurate performance while considering the constraints of voltage angle deviation The AWOALO method is actualized at MATLAB/Simulink working platform as well as outcomes are examined to two test cases and compared with various solution techniques such as base method, ant lion optimization (ALO) and whale optimization algorithm (WOA). The comparison outcomes determine the superiority of AWOALO method as well as confirm its potential to resolve problem. Finally, AWOALO technique display promising presentation based on shared power, that is, 100% power is deliver as VSG units compared to base, ALO, and WOA; however, the frequency and the deviation in frequency response due to dynamic condition is not encouraging.

Small signal stability improvement of a microgrid by the optimised dynamic droop control method

Renewable energy-based energy conversion technologies have become more relevant due to environmental considerations even though they are intermittent in nature. As a result, the concept of microgrid and microgrid control techniques have been evolved as major areas of power system research. Among different inverter control methods, the droop-based control method is more popular in microgrid systems due to its simplicity and non-requirement of expensive communication systems. The transient performance, power-sharing accuracy and decoupling between real and reactive power are improved by modifying the natural droop control method. In this study, the selected microgrid system consists of two inverters operating in parallel, two interconnecting lines and three loads. A state-space model of the microgrid is created based on the small-signal stability and the transient response is improved by introducing virtual impedance and dynamic droop gains. The different controller parameters are optimised using particle swarm optimisation ensuring stability. Eigenvalue analysis is done to analyse stability. The analysis of the response of the system for various disturbances validates the effectiveness of the proposed controller. The strategy developed ensures improved power-sharing capability with high values of natural droop gains without compromising stability by using optimised dynamic droop gains.

Tuning of power system stabilizer for small signal stability improvement of interconnected power system

This paper reports a new technique for achieving optimized design for power system stabilizers. In any large scale interconnected systems, disturbances of small magnitudes are very common and low frequency oscillations pose a major problem. Hence small signal stability analysis is very important for analyzing system stability and performance. Power System Stabilizers (PSS) are used in these large interconnected systems for damping out low-frequency oscillations by providing auxiliary control signals to the generator excitation input. In this paper, collective decision optimization (CDO) algorithm, a meta-heuristic approach based on the decision making approach of human beings, has been applied for the optimal design of PSS. PSS parameters are tuned for the objective function, involving eigenvalues and damping ratios of the lightly damped electromechanical modes over a wide range of operating conditions. Also, optimal locations for PSS placement have been derived. Comparative study of the results obtained using CDO with those of grey wolf optimizer (GWO), differential Evolution (DE), Whale Optimization Algorithm (WOA) and crow search algorithm (CSA) methods, established the robustness of the algorithm in designing PSS under different operating conditions.

A Supplementary Controller for Improvement of Small Signal Stability of Power System with Wind Power Penetration

Wind power penetration affects the dynamics and operational performance of a conventional power system. This article investigates the stability issues of a power system with the penetration of wind power from a doubly fed induction generator and direct drive synchronous generator. An approach to utilize an existing shunt flexible AC transmission system controller, static VAR compensator, for enhancing the small signal stability of a wind connected power system is discussed here. Supplementary stabilizing control for damping oscillatory modes is applied to static VAR compensator and suitable control input has been selected for the best damping performance of the proposed controller.

Improvement of small-signal stability of power system by controlling doubly fed induction generators of a large-capacity wind farm

AbstractMany wind turbine generations have been installed into power systems around the world, where in recent years doubly fed induction generator (DFIG) attracts a lot of attentions because of its efficiency and controllability. However, the DFIG is connected to the power system through inverters and originally does not have an ability to release the kinetic energy of the rotor or resorb the surplus power of the power system as the kinetic energy. Therefore, it has not been made clear how the DFIGs have an influence on small-signal stability in power systems. In this paper, we propose a control scheme of the DFIG and analyse its effect on the small-signal stability of the power system by eigenvalue calculations and time-domain simulations.

Study on Small Signal Stability Improvement by PSS of the Large-Scale Wind Power Integration

Study on Small Signal Stability Improvement by PSS of the Large-Scale Wind Power Integration

An investigation on the use of power system stabilizers for damping inter-area oscillations in longitudinal power systems

This paper presents the progress of an investigation on the use of power system stabilizers (PSSs) to enhance the damping of low-frequency inter-area modes in longitudinal power systems. A dynamic model of the Mexican Interconnected System (MIS) is adopted to evaluate the potential for small signal stability improvement by means of PSSs. Power oscillation flow studies, transfer function residues and controllability and observability characteristics are used to understand the nature of oscillation patterns, mode identification and PSSs siting. It is shown that PSSs can significantly enhance the damping of modal oscillations, especially under high stress conditions.