J. Nanda

Maiden Application of Bacterial Foraging-Based Optimization Technique in Multiarea Automatic Generation Control

A maiden attempt is made to examine and highlight the effective application of bacterial foraging (BF) to optimize several important parameters in automatic generation control (AGC) of interconnected three unequal area thermal systems, such as integral controller gains (KIi) for the secondary control, governor speed regulation parameters (Ri) for the primary control and frequency bias parameters (Bi), and compare its performance to establish its superiority over genetic algorithm (GA) and classical methods. Comparison of convergence characteristics of BF, GA, and classical approach reveals that the BF algorithm is quite faster in optimization, leading to reduction in computational burden and giving rise to minimal computer resource utilization. Simultaneous optimization of KIi, Ri, and Bi parameters which surprisingly has never been attempted in the past, provides not only best dynamic response for the system but also allows use of much higher values of Ri (than used in practice), that will appeal to the power industries for easier and cheaper realization of governor. Sensitivity analysis is carried out which demonstrates the robustness of the optimized KIi, Ri, and Bi to wide changes in inertia constant (H), reheat time constant (Tr), reheat coefficient (Kr), system loading condition, and size and position of step load perturbation.

Some new findings on automatic generation control of an interconnected hydrothermal system with conventional controllers

This paper deals with automatic generation control of an interconnected hydrothermal system in continuous-discrete mode using conventional integral and proportional-integral controllers. Appropriate generation rate constraint has been considered for the thermal and hydro plants. The hydro area is considered with either mechanical or electric governor and thermal area is considered with either single or double reheat turbine. Performances of mechanical governor, electric governor, and single stage reheat turbine and two stage reheat turbine on dynamic responses have been explored. Further, selection of suitable value of speed regulation parameter R and sampling period has been investigated. System performance is examined considering 1% step load perturbation in either thermal or hydro area.

Application of genetic algorithm to economic load dispatch with Lineflow constraints

This paper presents the solution of economic load dispatch (ELD) with Lineflow constraints through the application of genetic algorithm (GA). Two representative systems, i.e. IEEE 14 bus [Calculations and programs for power system networks (1986)] and IEEE 30 bus [Calculations and programs for power system networks (1986)] systems have been considered for the investigations. The ELD results with GA have been compared with those obtained through Classical Technique [IEE Proc C 139(4) (1992)], Linear Programming [IEEE Trans Power Syst, 1986] and Quadratic Programming [IEE Proc C 136(3) (1989)] techniques.

On some aspects of distribution load flow

This paper presents a comprehensive analysis and comparisons of the performances of the two commonly used models under different situations for distribution load flow. Investigations reveal that the computational efficiencies of both the models are more or less close over a wide range of loading condition. However, model 2 is less sensitive than model 1 for an increase in loading conditions, reduction in load power factor and increase in the branch R/X ratios.

A novel classical controller for automatic generation control in thermal and hydrothermal systems

This paper presents automatic generation control (AGC) of interconnected two equal area thermal system, two equal area hydrothermal System and five unequal area thermal system. Thermal plants have single reheat turbines with generation rate constraints of 3% per minute. The hydro plant in hydrothermal system has electric governor and has generation rate constraints of 270% per minute for raising generation and 360% per minute for lowering generation. A novel classical controller based on Integral and Double Derivative control is used in AGC and its performance is compared to several other classical controllers such as Integral (I), Proportional-Integral (PI), Integral-Derivative (ID) and Proportional-Integral-Derivative (PID) controllers. Integral squared error (I.S.E) and Bacteria Foraging (BF) techniques are used for optimization. Investigations reveal on comparison that Integral (I), Proportional-Integral (PI), Integral-Derivative (ID) or Proportional-Integral-Derivative (PID) controllers all provide more or less same response where as Integral - Double Derivative (IDD) controller provides much better response. Further, the controller action can be optimally delayed to provide the best dynamic response.

Optimal voltage control using a constant sensitivity matrix

Abstract This paper presents a new technique for improving system voltage profiles. Control of the voltage profile is achieved by minimizing the sum of the weighted voltage deviations at the buses using a first-order gradient technique. A constant symmetric load flow model in rectangular coordinates is employed. This permits efficient power computations requiring just four multiplications and a few additions per bus, irrespective of the system size. The constant Jacobian matrix used in load flow is also used in the calculation of the Langrangian multipliers throughout the optimization procedure. These features result in a computationally efficient algorithm. Results for two sample test systems using the proposed algorithm are presented.

Selection of sampling period for automatic generation control

The paper presents the analysis of automatic generation control (AGC) of a two-equal area reheat thermal system in the presence of generation rate constraints considering a discrete-continuous time mathematical model. The effect of variation of sampling period on optimum integral gain setting and system dynamic performance has been analyzed considering supplementary controllers based on conventional area control errors (ACEs) and new area control errors (ACENs). Investigations reveal that the optimum integral gain setting and system dynamic performance are hardly affected over a wide range of sampling period T for controllers based on conventional ACEs. Studies also reveal that the permissible sampling period is further enhanced with integral controllers based on new area control errors (ACENs).

Micro-grid operation and control of Photo-Voltaic power with canal based small hydro power plant

Solar panels installed over canals provide various advantages like excess power due to less temperature, reduction in the quantity of water loss due to evaporation etc. Water running in the canals also provides a source for small hydro power plants (SHP). This paper presents the control of SHP and Photo-Voltaic (PV) power of similar ratings operating together in a micro-grid. Limits imposed on hydraulic turbines due to cavitation have been considered. The SHP using synchronous machine is provided with integral controller and mechanical governor for frequency regulation in the micro-grid. The PV is maintained to operate at its maximum power. For part loading conditions, the PV is operated in de-rating mode so as to avoid operating the hydraulic turbine below manufacturers operating limits and to maintain the desired system frequency. Non-linear models of the governor, SHP and the PV has been considered in the study.

Sampled Data Automatic Generation Control Of A Two Area Reheat Thermal System With Modified Area Control Error

This paper deals with Automatic Generation Control (AGC) of a two area reheat thermal system with modified area control error (ACEM) considering operation of the system in the continuous-mode and that of the controller in the discrete mode. ACEM is the weighted sum of frequency deviation, tie-power deviation and inadvertent interchange energy. Studies show that the AGG-strategy based on ACEM provides constancy of frequency and tie-power flow, zero steady state error in inadvertent interchange energy and negligible error in time error accumulation in the steady state. Further the dynamic responses of the system obtained with controllers based on ACEM are close to the.responses based on new area control error ( ACEN - Ref [21] ) but are much superior to the corresponding responses achieved with controllers based on conventional area control error.