An enhanced and auto-tuned power system stabilizer based on optimized interval type-2 fuzzy PID scheme

Abstract

SummaryIn this paper, an innovative optimized type-2 fuzzy PID power system stabilizer is proposed to enhance the stability of the power system. This stabilizer is a combination of PID controller and type-2 fuzzy set whose parameters have been optimized with Hybrid Big Bang-Big Crunch (HBB-BC) algorithm. This combination makes the stabilizer to be flexible in face of changing in operating points of the power system and also encountering to power system nonlinearities and uncertainties. The main sources of uncertainties in the power system are the uncertainties in operation conditions, power system parameters, and measurement devices. Uncertainties do not allow the stabilizer to offer its full capabilities, and hence the efforts of the stabilizer may not satisfy the expectations. In order to evaluate the performance of the proposed controller, 2 case studies under different disturbances are investigated. The obtained results show that the proposed stabilizer can suitably provide appropriate damping in oscillatory modes of the system. KEYWORDSHybrid Big Bang-Big Crunch algorithm, interval type-2 fuzzy-PID, low-frequency oscillation, power system stabilizer, uncertainty | INTRODUCTIONThe stability of power system plays an important role in the power system studies area. The frequency and voltage level should be kept at a suitable range, while disturbances like changing in loading condition, generation loss, or the loss of tie lines are occurred. Low-frequency oscillations (LFO) are in the range of 0.1 and 3.0 Hz that can be divided into local and inter-area oscillations. 1 If these oscillations continue, the ability of tie lines for transmitting electrical energy will be reduced, and the power system may experience instability. These oscillations usually occur during or after a system disturbance. Therefore, it is essential to use control methods in order to eliminate these LFO. In order to enhance the stability of the power system, a power system stabilizer (PSS) has been installed in the exciter system of the generator. 2 The power system stabilization can be established centralized or decentralized. A centralized controller has an almost perfect performance in damping oscillation phenomena if it is intelligently tuned which is often a hard task. In addition, such a controller needs safe communication channels to transmit data. However, the delay in the communication system is an inevitable issue. This time delay may cause deterioration on oscillation damping and even result to an unstable power system. 3 One way to solve this problem is the use of predictive control. In this method, the model identification

A frequency domain model-based design of PSS and TCSC controller for damping the small signal oscillations in the power system

“…A blend of PID controller and type-2 fuzzy set using Hybrid Big Bang-Big Crunch approach is proposed in Shokouhandeh and Jazaeri. 40 In the present work, a frequency domain model-based method is proposed for designing a lead-lag PSS and a TCSC controller (the proposed controllers) for damping the power system oscillations. For this purpose, a reference model is first designed which incorporates the desired specifications of the control system.…”

“…The authors in Naresh et al have proposed improved harmony search algorithm for coordinated design of multiple PSSs and TCSC controllers and compared with the methods of genetic algorithm, particle swarm optimization, harmony search algorithm, and bacterial swarm optimization. A blend of PID controller and type‐2 fuzzy set using Hybrid Big Bang‐Big Crunch approach is proposed in Shokouhandeh and Jazaeri …”

Optimal Estimation of Capacity and Location of Wind, Solar and Fuel Cell Sources in Distribution Systems Considering Load Changes by Lightning Search Algorithm

“…In the this study, loss and voltage deviations are selected as the main objectives. The ohmic losses of the lines can be calculated as equation (1). The loss function is the sum of the ohmic losses of all the lines [13][14]…”

“…Renewable energy sources such as solar and wind have been increasingly used in the electricity industry to reduce fuel costs and thus generate significant profits and clean air growth. This growth has been supported, on the one hand, by fears of a shortage of conventional energy resources and on the other by clean energy production, by interested governments [1]. The dependence of solar and wind power generation on solar radiation and wind speeds has led to lower reliability in renewable systems.…”

“…By using the weight coefficients ω1 and ω 2 , the two objective functions are weighted to have an equal effect on the final value of the objective function. Connecting the distributed generation sources to the feeder in question should be done in such a way that the normal operation of the network does not change.…”