Malabika Basu

Simulated Annealing Technique for Dynamic Economic Dispatch

Dynamic economic dispatch (DED) is one of the main functions of power system operation and control. It determines the optimal operation of units with predicted load demands over a certain period of time with an objective to minimize total production cost while the system is operating within its ramp rate limits. This paper presents DED based on a simulated annealing (SA) technique for the determination of the global or near global optimum dispatch solution. In the present case, load balance constraints, operating limits, valve point loading, ramp constraints, and network losses using loss coefficients are incorporated. Numerical results for a sample test system have been presented to demonstrate the performance and applicability of the proposed method.

A 12-kVA DSP-Controlled Laboratory Prototype UPQC Capable of Mitigating Unbalance in Source Voltage and Load Current

This paper reports the development of a laboratory prototype of a fully digital DSP-controlled 12-kVA unified power quality conditioner (UPQC), capable of compensating for both the supply voltage and the load current imperfections. A fully digital controller based on the TMS320F2812 DSP platform is implemented for the reference generation as well as control purposes. The delay problem in the digital controller is overcome by application of a fast DSP, a compact control technique and proper flow of control steps in the DSP software. A phase-locked loop-less software grid synchronization method has been implemented for the effective operation of the UPQC under conditions of grid frequency variation. A sequence-based compensation strategy has been developed to compensate for balanced and unbalanced sags while accommodating the fact that the voltage injection capability of the UPQC is limited. The prototype UPQC power circuit, control features, and control algorithm along with experimental results are presented in this paper.

Hopfield neural networks for optimal scheduling of fixed head hydrothermal power systems

Abstract This paper highlights a simple and effective approach of scheduling thermal plants in coordination with fixed head hydro units. It uses Hopfield neural network formulation to determine the optimal schedules of hydro and thermal power plants. The method is demonstrated by its application to a test system. The results determined by the proposed method are compared to those found by Newtons method.

A Review of Existing Microgrid Architectures

The future electricity network must be flexible, accessible, reliable, and economic according to the worldwide smartgrid initiative. This is also echoed by the Sustainable Energy Authority of Ireland (SEAI) and European Electricity Grid Initiative (EEGI). In order to facilitate these objectives and to reduce green house gas (GHG) emission, research on various configurations of microgrid (μG) system is gaining importance, particularly with high penetration of renewable energy sources. Depending on the resource availability, geographical locations, load demand, and existing electrical transmission and distribution system, μG can be either connected to the grid or can work in an autonomous mode. Storage can also be a part of the μG architecture. This paper presents a critical literature review of various μG architectures. The benefits of grid-connected or isolated μG with storage have also been identified.

Particle Swarm Optimization Based Goal-Attainment Method for Dynamic Economic Emission Dispatch

Dynamic economic emission dispatch is an extension of the conventional economic emission dispatch problem that takes into consideration the limits on the ramp rate of the generating units. This article proposes particle swarm optimization based goal attainment method for solving dynamic economic emission dispatch problem. In this article, cost and emission are treated as competing objectives. Assuming that the decision maker has goals for each of the objective functions, the multiobjective problem is converted into a single-objective optimization by goal-attainment method which is then handled by particle swarm optimization method. The solution methodology can offer optimal noninferior solution for the decision maker. Results of the application of the proposed method are presented.

Combined Heat and Power Economic Dispatch by Using Differential Evolution

Abstract This article presents differential evolution to solve the combined heat and power economic dispatch problem. Differential evolution, an improved version of the genetic algorithm and evolutionary programming, is a very simple, fast, and robust global optimization technique. The proposed algorithm is illustrated for a test system, and the test results are compared with those obtained from particle swarm optimization and evolutionary programming.

Performance study of UPQC-Q for load compensation and voltage sag mitigation

Unified power quality conditioner (UPQC) is one of the major custom power solutions that is capable of mitigating the effect of supply voltage sag at the load end or the point of common coupling (PCC). It also prevents load current harmonics from entering the utility and corrects the input power factor of the load. The control of series compensator is such that it injects voltage in quadrature advance to the supply current, so that no active power is consumed by the series compensator at steady state. The UPQC employing this type of quadrature voltage injection in series is termed UPQC-Q. The present paper discusses the VA requirement issues of series and shunt compensators of UPQC-Q and its performance is verified in a laboratory prototype. The phasor diagram, control block diagram and typical experimental results are presented to confirm the validity of the theory.

An Interactive Fuzzy Satisfying-Based Simulated Annealing Technique for Economic Emission Load Dispatch with Nonsmooth Fuel Cost and Emission Level Functions

The economic emission load dispatch problem treats economic and emission as competing objectives for optimal dispatch, which requires some form of conflict resolution to arrive at a solution. Assuming that the decision maker (DM) has imprecise or fuzzy goals for each of the objective functions, the multiobjective problem is transformed into a minimax problem, which is then handled by the simulated annealing (SA) technique. The solution methodology can offer noninferior optimal solution for the DM. Numerical results for a sample test system have been presented to demonstrate the performance and applicability of the proposed method.

UPQC for Power Quality Improvement in DG Integrated Smart Grid Network: a Review

Quality of power supply has become an important issue with the increasing demand of Distributed Generation (DG) systems either connected to the grid through some power electronics grid-tie inverters or to work in isolated (microgrid) mode towards the development of a smart grid network. In this paper a technical review of Integration of Unified Power Quality Conditioner (UPQC) in Distributed Generation Network has been presented. Though the primary task of UPQC is to minimize the grid voltage and load current disturbance along with the reactive and harmonic power compensation, additional functionalities like compensation of voltage interruption and active power transfer to the load and grid have also been identified. Connection methodologies with their pros and cons are also described. Recent improvements in capacity expansion techniques and future trends for the application of UPQC to cope up with the expanding DG capacity are also reviewed.

Intelligent Islanding and Seamless Reconnection Technique for Microgrid With UPQC

A new proposal for the placement, integration, and control of unified power quality conditioner (UPQC) in distributed generation (DG)-based grid connected/autonomous microgrid/microgeneration (μG) system has been presented here. The DG converters (with storage) and the shunt part of the UPQC Active Power Filter (APFsh) is placed at the Point of Common Coupling (PCC). The series part of the UPQC (APFse) is connected before the PCC and in series with the grid. The dc link can also be integrated with the storage system. An intelligent islanding detection and reconnection technique (IR) are introduced in the UPQC as a secondary control. Hence, it is termed as UPQCμG-IR. The advantages of the proposed UPQCμG-IR over the normal UPQC are to compensate voltage interruption in addition to voltage sag/swell, harmonic, and reactive power compensation in the interconnected mode. During the interconnected and islanded mode, DG converter with storage will supply the active power only and the shunt part of the UPQC will compensate the reactive and harmonic power of the load. It also offers the DG converter to remain connected during the voltage disturbance including phase jump.