Rintu Khanna

Power system stability enhancement with SMES

This paper presents improvement of transient stability of power systems with superconducting magnetic energy storage (SMES). SMES has been connected at the generator terminal for single machine connected to infinite bus (SMIB). A comparison of performance of proportional type of SMES (P-SMES) proportional-Integral type of SMES (PI-SMES)and that of an Optimally Switched Dynamic Brake (OSDB) suggested by Minisey et al is presented. Transient stability investigations were carried out on SMIB with SMES for diverse loading conditions and different fault clearing times. The results established superior performance of SMES in damping transient swings over optimally switched conventional dynamic brake.

Power system stability using fuzzy logic based Unified Power Flow Controller in SMIB power system

The paper presents a control method of damping low frequency power system oscillations using fuzzy logic based Unified Power Flow Controller (UPFC) installed in a single-machine infinite-bus (SMIB) power system. The objective of the Fuzzy Logic based UPFC controller is to damp power system oscillations. UPFC controller based upon amplitude modulation index of shunt converter (exciter) mE has been designed. System response with Proportional UPFC controller & Proportional fuzzy logic (using mamdani-type inference) based UPFC controller (PF-UPFC) are compared at variable loading conditions. Respective models have been developed and simulated in Matlab Simulink. The Fuzzy Logic based UPFC controller is designed by selecting appropriate controller parameters based on the knowledge of the power system performance. The results of these studies show that the designed controller has an excellent capability in damping power system oscillations.

Design of AVR and ALFC for single area power system including damping control

This paper presents the combined control for single area power system including automatic voltage control by using automatic voltage regulator (AVR) and automatic frequency control by using automatic load frequency control (ALFC). The paper shows the coupling effects between the two loops, which are studied by extending the linearised ALFC system to incorporate the excitation system. A proportional integral gain controller is included in the AVR loop and conventional integral controller in ALFC loop so that system responses become better in terms of peak deviations and settling time. Damper winding is included in the AVR loop which is present on the rotor of the synchronous generator. Simulation studies reveal that the response of the system becomes better in terms of peak deviations (overshoots and undershoots) and settling time when damper winding is included in the system.

Optimal placement and sizing of DG comparison of different techniques of DG placement

The increasing power demand and the deficiency in generating capacities have set the way towards Distributed Generation. Distributed Generation (DG) is assuming widespread popularity owing to its potential to solve numerous issues like the power system de-regulation; meeting the rising power demand; improving voltage profile; reduction in power losses etc. The Optimum Location of DG and optimum DG Sizing are the two critical issues in the integration of DG with the electric grid because the improper placement and improper sizing of DG in power system can not only leads to the enhanced total power losses but can also damage the normal operation of power system. Optimal placement of DG units is a nonlinear optimization problem. This paper proposes a methodology to calculate the optimal location and effective optimal size. The influence of variation in location of DG with respect to the total power losses and voltage in the system is also carried out. The proposed methodology is tested on 33 bus radial distribution network. The obtained results are exhibited in graphical manner. The results achieved from the proposed methodology are paralleled with that of the exhaustive load flows.

Intelligent control for a radial distribution system with distributed generation

Now days the Distribution Network Organizations (DNOs) have set some rules to maintain the voltage at a specified level to control the increase of voltage variations and controls the power factor. The main objective of this paper is that in cases of weak networks the voltage level is maintained by the distributed generation (DG) by importing or exporting active and reactive power. To control the voltage/power factor, a distributed generation (DG) is connected to the distribution system (taking 2-bus system) and - the study is performed with the constant loading condition with (i) Automatic Voltage Control (ii) Automatic Power factor Control (iii) Automatic voltage and power factor control and (iv) Fuzzy Logic based Power Factor Control using Matlab/simulink.

A hybrid approach for promoting low carbon technologies in distributed generation planning

The greatest challenge for power utilities is to meet exponentially increasing energy demand subjected to the constraints of sustainable development with clean energy apart from economic viability. Renewable DGs, in spite of high investment cost and intermittent generation, are compulsive choice for environment friendly planning and sustainable growth. Clean energy DG technologies can provide solution to ever increasing power demand in sustainable and cost effective manner by adopting appropriate incentive mechanism. Clean energy technologies can also be encouraged by penalizing the conventional resources for harmful emissions. The proposed method minimizes the annual cost by maximizing the emission reduction and carbon credit revenue. The proposed formulation yields solution in terms of type, optimal size and location while fulfilling the criterion in terms of economic, technical or techno-economic. The objective function comprises of energy purchase, losses, capital, operational and GHG emission costs. Importance of each objective is mapped with optimal weight allocation, thereby maintaining the consistency among all objectives. A hybrid optimization technique based on Harmony Search integrated with Teaching-Learning is used to enhance the search process. The merit of the proposed algorithm is dynamic tuning of control parameters which enhances the convergence property of the solution algorithm. Results indicate that renewable DG technologies can become financially viable with appropriate price mechanism depending on planners objective.

Demand side management in a smart grid environment

The demand side management (DSM) comprises techniques and policies which aim at equalizing energy consumption levels over the day. As opposed to the supply side management involving the addition of new generation units and total installed capacity, the idea here is not only to increase the energy to be supplied, but also to control the shape of consumption by applying energy management techniques. The main challenge in the implementation of a DSM program is the quest for knowledge of the daily behavior of loads in the electrical system, which is generally not available from the systems based on conventional electromechanical meters. In such a scenario, the emergence of novel technologies like Smart Grid technology, creates an environment for convergence between the infrastructures of generation, transmission, distribution, information technology and digital communication infrastructure which enables the exchange of information and control actions among the various segments of the power grid. The paper throws light on the research trends within the area of demand side management in a smart grid environment and proposes a scheduling scheme using genetic algorithm for load management. Simulation results confirm that the proposed algorithm efficiently reduces the PAR and electricity consumption cost.

Effect of Static Synchronous Series Compensator on Power Balancing in Wind Farms

Renewable energy sources such as hydro, solar, wind, biomass, geothermal, and tidal can be used as an alternative source of power in remote area applications, and also, such sources provide a clean and environment-friendly power. However, the main drawback of using renewable energy sources for these deserted places is the fluctuating nature and that creates problems in matching the load demand. Combinations of renewable energy sources with conventional generators make the solution more viable and affordable. For overcoming the technical and financial contingencies associated with renewable energy sources, proper control of power, coordination of subsystems, energy storage, and power quality are the main challenges. The present paper describes the theory and simulation of SSSC, a flexible alternating current transmission systems (FACTS) controller used in the wind power system. Two groups of wind turbine generator systems are used to design this wind power system which is producing electricity for isolated locations. In this paper, SIM POWER SYSTEM toolbox of MATLAB software is used for system simulation to investigate the effect of SSSC on the voltage profiles under different loading conditions and also considered for active and reactive power congestion relief of the induction machines.

Control of Reactive Power of RES-Based Hybrid Isolated Power System Using UPFC

In India, Electric power system network becomes very complex and Flexible AC transmission Systems (FACTS) controllers are deployed for overall control of system. In this paper, most efficient FACTS controller Unified Power Flow Controllers (UPFC) is used for studying the dynamic control of reactive power of RES (Renewable Energy Sources)-based hybrid isolated power system (HIPS). The extensive time-domain simulations are carried out in the proposed HIPS test system. This paper presents the reactive power compensation capability and illustrating the other control features of this controller. UPFC has been implemented in test system for dynamic compensation and improving voltage regulation. The present paper describes the analysis of combination of the UPFC, machines, and the network has been done in SIM POWER SYSTEM/MATLAB software.

Analysis of L-Z source inverter under different modulation techniques

This paper discusses the new breed of inverters called Z-source inverters, what makes them special is their property to carry out inversion and boost operation simultaneously. New modulation schemes has been developed for these inverters so as to utilize their ability of boost operation, in this category lies a L-z source inverter which unlike other topologies of Z-source inverters do not uses capacitor to boost the voltage which make it the most comprehensive inverter. Here a study is carried out comparing the L-z source inverter with conventional z-source inverter in terms DC link voltage, THD, cost etc.