Rajesh Joseph Abraham

AGC of a hydrothermal system with thyristor controlled phase shifter in the tie-line

This paper presents the analysis of automatic generation control (AGC) of a two-area interconnected hydrothermal system considering a thyristor controlled phase shifter (TCPS) in series with the tie-line. It is possible to stabilize the system frequency and tie-power oscillations by controlling the phase angle of TCPS which is expected to provide a new ancillary service for the future power systems. A control strategy using TCPS is proposed to provide active control of system frequency. Gain settings of the integral controllers without and with TCPS are optimized using integral squared error (ISE) technique following a step load disturbance in either of the areas by minimizing a quadratic performance index. Analysis reveals that a TCPS is quite capable of suppressing the frequency and tie-power oscillations effectively under the occurrence of sudden load changes in any of the areas as compared to that obtained without TCPS

Effect of capacitive energy storage on automatic generation control

In the present work, the effect of a small rating capacitive energy storage (CES) unit on automatic generation control (AGC) of a two area interconnected power system is studied for the improvement of dynamic performance. Time domain simulations are used to study the performance of multi-unit multi-area system in the presence of GRC without and with CES units. Gain settings of integral controller are optimized using the integral square error (ISE) technique. Results reveal that a small capacity CES unit is quite capable of improving the dynamic performance of AGC following a step load disturbance

AGC System after Deregulation Considering TCPS in Series with the Tie-Line

Abstract This paper presents the study of automatic generation control (AGC) of two area interconnected power system after deregulation, considering a thyristor controlled phase shifter (TCPS) in series with the tie-line. It is possible to minimize the system frequency and tie-power oscillations by controlling the phase angle of TCPS which is expected to provide a new ancillary service for the future power system. Effect of TCPS is examined for three different cases, i.e. (1) unilateral contract, (2) bilateral contract and (3) contract violation. Analysis reveals that a TCPS is quite capable of suppressing the frequency and tie-power oscillations effectively as compared to that obtained without TCPS.

AGC of a hydrothermal system with SMES unit

In this paper, the AGC improvement of a two area interconnected hydrothermal system along with a Superconducting Magnetic Energy Storage is proposed. Generation Rate Constraints are also considered. Integral Squared Error technique is used to obtain the optimum values of the integral gain settings. Analysis reveals that the dynamic responses are considerably improved in the presence of the SMES unit. A comparison and analysis of the dynamic performances without and with SMES unit in the presence of GRC brings out the superior performance of the SMES unit in suppressing the frequency and inter-area tie-power deviations from their nominal values followed by a step load perturbation.

QFT based robust controller for DC-DC Boost Converter

In this paper, we have applied Quantitative Feedback Theory (QFT) to design a compensator for a Boost Converter in Continuous Conduction Mode. Being an advanced robust control technique, QFT is able to meet all the closed loop specifications of the system and make it insensitive to parametric variations, load current perturbations and duty ratio variations for a given set of plants. The design and analysis of voltage-mode controlled Boost converter are done using Matlab® software and satisfactory results are obtained.

Hydrothermal power system AGC with GA optimized controllers and Capacitive Energy Storage

In this work, the Automatic Generation Control of an interconnected hydrothermal power system with a small capacity Capacitive Energy Storage augmented to both thermal and hydro area has been investigated. The effect of an integral controller as well as a PID controller whose gains are tuned by Genetic Algorithm technique has been examined and compared. The optimum values of the integral and PID controller gains without and with capacitive energy storage (CES) for both the areas are obtained by minimizing Integral Time Squared Error (ITSE) criterion. Simulation studies and a comparison of the dynamic responses reveal the improvement of AGC in terms of peak amplitudes and deviations in frequencies of both the areas, as well as tie line power with the PID controller and augmentation of Capacitive Energy Storage unit.

Improving the AGC performance in a power system with Thyristor Controlled Series Compensator

This study makes a attempt to develop a linear incremental model for a Thyristor Controlled Series Compensator (TCSC) and its application in improving the Automatic Generation Control (AGC) performance in an interconnected power system. Optimal gain settings of the integral controllers in the control areas are obtained using Integral Squared Error technique by minimizing a quadratic performance index. The performance of the power system under realistic situation is investigated by including the effects of Generation Rate Constraint (GRC) and governor Dead Band (DB) in the simulation studies. Simulation studies carried out in MATLAB on a sample two-area multi-unit thermal-thermal system validates that a Thyristor Controlled Series Compensator in series with tie-line can effectively damp out the frequency oscillations in both the areas and tie-power oscillations following a small load perturbation, thereby improving the settling time and overall AGC performance.

Comparative analysis of AGC performance in an interconnected power system with HVDC and TCSC considering GRC and deadband non-linearities

Power electronics applications in power system has significantly increased to improve the capacity of the existing system as well as the power quality. This paper discusses a comparative analysis of Thyristor Controlled Series Compensator (TCSC) and High Voltage Direct Current (HVDC) link to improve the performance of Automatic Generation Control (AGC) of two-area interconnected thermal-thermal power system considering non-linearities effects of Generation Rate Constraints and Governor Dead band. A quadratic performance index is minimized to obtain optimal integral gain settings of the control areas. Simulation results clearly validates that, incorporating TCSC and HVDC effectively stabilizes area frequency and tie-line power oscillations after a sudden load perturbation. It is evident that TCSC improves AGC performance better in comparison with HVDC.

A Genetic Proportional Integral Derivative Controlled Hydrothermal Automatic Generation Control with Superconducting Magnetic Energy Storage

In this work, the Automatic Generation Control of an interconnected hydrothermal power system with Superconducting Magnetic Energy Storage (SMES) has been investigated. The gain settings of integral controller as well as Proportional Integral Derivative (PID) controller are tuned by Integral Time Squared Error (ITSE) criterion using Genetic Algorithm. Simulation, comparison and analysis of dynamic performances in the presence of Generation Rate Constraints brings out the superior performance of SMES units and PID controller in suppressing frequency and inter area tie line power deviations from their nominal values followed by a step load disturbance in thermal area.