S. Balamurugan

Control of Heavy-duty Gas Turbine Plants for Parallel Operation Using Soft Computing Techniques

Abstract Gas turbine generators, normally used in isolated operation, require an effective control and design for their parallel operation. Otherwise, the load variations and set-point variations may cause severe stability problems. Soft computing techniques, such as genetic algorithms, artificial neural networks, and fuzzy logic, have been utilized for developing a controller for a gas turbine plant. The proportional-integral-derivative controller is used to control the gas turbine plant because of its versatility, high reliability, and ease of operation. For better performance, the gains of the proportional-integral-derivative controller have been tuned using the Ziegler–Nichols method and genetic algorithm. The artificial neural network and fuzzy controllers are developed, and the performance is compared with the conventional proportional-integral-derivative controller. The results show that the optimal time domain performance of the system can be achieved with the fuzzy logic controller. The fuzzy logic controller removes the steady-state error in less time with no overshoot and oscillation.

Laboratory Model for Teaching Real Power Flow Control in Transmission Line

This paper explains the experiments developed in the laboratory to teach undergraduate students the different aspects of power system operation and control. Simulation software are used in most of the colleges to teach different aspects of power system. Students feel difficult to understand the power system behavior in physical sense. This paper describes a model power system built in the Electrical Engineering Department of Amrita School of Engineering, Coimbatore. The model consists of two bus system connected by two parallel transmission lines. The power flow in the transmission line is controlled by varying voltage magnitude, line reactance, passive and active series compensation.

Development of Controller for Parallel Operation of Gas Turbine Plants

Abstract Gas turbines are used in biomass plants for energy conversion. An effective control scheme is required for optimal performance during parallel operation. In this article, an optimal proportional-integral-derivative controller is developed for isolated operation. The gas turbines are then connected in parallel, and an effective control scheme is developed for their parallel operation. The response of the gas turbine plants with a proportional-integral-derivative controller in parallel operation shows improved performance.

Laboratory model to teach power system stability

To teach and demonstrate the Power System Stability aspects to the undergraduate students, a laboratory model has been developed. Computer based simulation softwares are used to teach different aspects of power system by most of the Institutions. These simulation studies often do not demonstrate the physical sense of power system behavior to students. Moreover, making the students to visualize the effect of instability is a very big challenge faced by the teaching community. This paper describes the experimental set up built in the Electrical Engineering Department of Amrita School of Engineering, Coimbatore, consisting of an alternator connected to infinite bus through parallel transmission lines. In this experimental setup, the generator is brought to instability by changing the operating conditions. Further, the oscillation is controlled and brought back to stability by controlling the excitation and line reactance. This gives the clear idea about stability and its enhancement to the students.

Decentralised automatic generation control strategy for a three area bilateral power market

Restructured power system creates a competitive environment where different players like generating and distribution companies enter into auction or negotiations. Under bilateral model, GENCOs schedule power based on the contracts made with the DISCOs. Moreover, the transmission companies are made to operate at the contracted value. Ensuring system stability and reliability is a big challenge under restructured power system. The paper proposes a control strategy for load frequency control in a three area deregulated power system, with the objective to regulate the system frequency and TRANSCO power variation. The effectiveness of the control strategy is tested during contract violations.

Laboratory model to teach Surge Impedance Loading

This paper explains the development of laboratory model to teach Surge Impedance Loading to the undergraduate students. Simulation software used for teaching power systems fails to give physical sense to the students. The scaled down model of transmission line is developed at the Electrical Engineering development of Amrita school of Engineering, Coimbatore. The flat voltage profile is observed in the line when the line is loaded to Surge Impedance Loading. Further the Surge Impedance Loading and phase shift are studied during series and shunt compensation. Shunt capacitor compensation improves only Surge Impedance Loading but increases the phase shift. Series capacitor compensation improves Surge Impedance Loading and also stability by decreasing the phase shift.

Development of ANFIS-based reference flux estimator and FGS-tuned speed controller for DTC of induction motor

ABSTRACT This paper discusses about self-regulating the reference flux in induction motor (IM) direct torque control (DTC) drive by fuzzy logic. Self-regulation is improved by using “Artificial Neural Network (ANN)” and “Adaptive Network Based Fuzzy Inference System (ANFIS)” based reference flux estimators. Furthermore, PI speed controller is investigated to develop the performance of the drive. Two different PI speed controller tuning strategies, manual and Fuzzy Gain Scheduling (FGS), are compared for load torque disturbance. The results clearly show that the modified DTC of IM with “ANFIS-based reference flux estimator and FGS-tuned PI speed controller” is most suitable for torque ripple reduction and speed control.

Pass through congestion management in deregulated power system using genetic algorithm

Transmission grid infrastructure is a backbone for the competitive electric power market operation. Yet, the need for improvement of suitable transmission system is emphasized due to the dominance of transmission congestion in various parts of the grid. Such transmission line overloads turns critical to the system security and furthermore suppress the competitiveness of the power market. Congestion mitigation is therefore an inevitable function that is likely to be employed with quick response. Nordic countries address this issue by splitting the market into areas and implement using the spot pricing strategy. Pass through congestion is a one such unsolved prevailing issue in the area pricing strategy. In this paper, the solution to the pass through congestion using market splitting method is dealt. The mathematical formulation for a simple three area system with pass through congestion management is built using MATLAB. The quantity of power exchange between the areas is determined based on the GA optimization technique. This aids in the evaluation of social surplus confirming the well-being of the society. The obtained results are validated using the conventional graphical approach.

Area and economic participation factor calculation of GENCOs in a multi area competitive power system

Deregulation creates competitive market with GENCOs and DISCOs as the market players. The GENCO offers and DISCO bids are submitted to market operator who clears the market with the aim to maximize social welfare. The power trading is done in an open access between in-merit GENCOs and DISCO. The allotted power demand of each in-merit DISCO is met by in-merit GENCOs that generates contracted power. Thus, GENCOs share a portion of the power demand of each DISCO. The contribution of each GENCO to meet power demand of a DISCO is represented in terms of area participation matrix. During contract violation, willing GENCOs shares the un-contracted power demand based on economic participation factor. Thus, GENCOs generate the contracted (during contracted condition) and un-contracted power (during violation) based on area participation factors and economic participation factors respectively. This is achieved with the help of automatic generation control. This paper assumes a two area system with different market conditions and develops a generalized mathematical expression to calculate these factors based on the allotted in-merit GENCO power and available willing GENCO power. These factors are then incorporated in the mathematical model of two area system under deregulated environment. The performance of the developed model is tested under tie line bias control strategy to check whether the GENCOs and TRANSCO power is based on the participation factors.

Real power flow control in transmission system using TCSC

Interconnected transmission system provides a wide scope for power sharing thereby avoiding chances of overloading in transmission lines. But this can be achieved only with proper control on the transmission network. The aim of this work is to improve the real power flow in the transmission lines by varying the transmission line reactance. Real power flow can be improved by series compensation using a Static Series Compensator (SSC). A fixed capacitor connected in series with the transmission line can effectively reduce the transmission line reactance thereby improving real power flow. But series compensation using a capacitor can provide only fixed compensation, a smooth variation in reactance cannot be achieved. In this paper a Thyristor Controlled Static Series Compensator (TCSC) is used for controlling the power flow in the transmission line. Open loop control of TCSC by varying the firing angle is simulated using MATLAB. A hardware implementation of TCSC to analyse the power flow control is deployed in a 2-bus system.