Vinay Pant

Evolutionary programming based optimal placement of renewable distributed generators

An evolutionary programming (EP) based technique has been presented for the optimal placement of distributed generation (DG) units energized by renewable energy resources (wind and solar) in a radial distribution system. The correlation between load and renewable resources has been nullified by dividing the study period into several segments and treating each segment independently. To handle the uncertainties associated with load and renewable resources, probabilistic techniques have been used. Two operation strategies, namely “turning off wind turbine generator” and “clipping wind turbine generator output”, have also been adopted to restrict the wind power dispatch to a specified fraction of system load for system stability consideration. To reduce the search space and thereby to minimize the computational burden, a sensitivity analysis technique has been employed which gives a set of locations suitable for DG placement. For the proposed EP based approach, an index based scheme has also been developed to generate the population ensuring the feasibility of each individual and thus considerably reducing the computational time. The developed technique has been applied to a 12.66-kV, 69-bus distribution test system. The solutions result in significant loss reduction and voltage profile improvement.

Analytical Approach for Well-Being Assessment of Small Autonomous Power Systems With Solar and Wind Energy Sources

This paper presents a systematic analytical approach for the well-being assessment of small autonomous power systems (SAPSs) with wind and solar energy sources. The proposed technique accounts for the uncertainties associated with solar irradiance, wind speed, demand, and outages of various generating units. The impact of wind power fluctuation on the system stability is also assessed by limiting the wind power dispatch to a certain percentage of system load. Well-being assessment and production costing simulation for SAPS are performed using proposed analytical approach and Monte Carlo simulation (MCS) method, and then, obtained results are compared in terms of accuracy and computational time. The comparison shows that the developed technique requires less computational time than MCS method, with reasonable accuracy, and thus, validates the usefulness of proposed analytical method. The impact of renewable energy penetration on a SAPS is also analyzed using the proposed method.

Voltage source inverter driven multi-phase induction machine

Multi-phase (more than three phases) drives possess several advantages over conventional three-phase drives such as: reducing the amplitude and increasing the frequency of torque pulsations, reducing the rotor harmonic currents, reducing the current per phase without increasing the voltage per phase, lowering the dc link current harmonics and higher reliability. By increasing the number of phases it is also possible to increase the power/torque per rms ampere for the same volume machine. This paper, therefore, presents a simple d–q model of a multi-phase induction machine suitable for analyzing the transient, steady state and dynamic behavior of the machine under balanced operating condition. In the analytical model, the effects of common mutual leakage reactance between the two three-phase winding sets have been included. The model has been developed in general reference frame and is suitable for analysis of the machine behavior with an arbitrary angle of displacement. 2003 Elsevier Ltd. All rights reserved.

A novel approach for sensitivity calculations in the radial distribution system

In this paper, a novel approach for calculating the sensitivities of active/reactive power loss and voltage magnitudes with respect to active/reactive power injection at any bus in the radial distribution system is presented. In a radial distribution system, the changes in bus voltages and branch flows due to active/reactive power injection at any bus depend on the network topology. The key to the present method is the formation of a matrix whose structure is dependent only on the network topology. The proposed method is able to calculate the various sensitivity indices for single as well as multiple sources in the system. It is also able to handle all possible radial distribution system structures regardless of the system size proficiently. The results obtained by the proposed method have been compared with the simulated (conventional load flow) and the adjoint network approach results

Optimized daily scheduling of wind-pumped hydro plants for a day-ahead electricity market system

This paper presents a new approach for optimal daily scheduling of hybrid wind-pump storage hydro (WPSH) facility owned by an independent power producer (IPP). WPSH system has been considered as a participant of a day-ahead electricity market and mathematical formulation has been developed accordingly. The aim of developed formulation is to maximize the profit to the WPSH owner. The usefulness of the developed mathematical formulation has been tested on a test system and the solution has been obtained by Linear Programming technique using Primal-Dual Interior-Point method.

Stability analysis of a multi-phase (six-phase) induction machine

Abstract The stability study of a multi-phase (six-phase) induction machine has been performed by applying the eigenvalues stability criterion to the small displacement equations obtained by linearization about an operating point. The eigenvalues provide a simple means of predicting the behavior of an induction machine at any balanced operating condition. The eigenvalues are dependent upon the parameters of the machine and it is difficult to relate analytically a change in an eigenvalue with a change in a specific machine parameter. It is possible, however, to identify an association between eigenvalues and machine variables. Therefore, in this paper, the stability of the machine under small perturbation of machine variables has been examined from the placement of the eigenvalues. The effect of common mutual leakage reactance, which depends upon the winding pitch and the displacement angle between the two three-phase stator winding sets, and the effect of harmonics have been included in this study.

Steady-state modeling and analysis of six-phase synchronous motor

Steady-state analysis is needed for a better understanding of the operational behavior of a six-phase synchronous motor. Therefore, this paper primarily addresses the steady-state analysis of an asymmetrical six-phase synchronous motor, including the development of a mathematical model employing Parks (dq0) transformation, valid for different terminal conditions. These conditions include the motor operation with input supply at both sets of the three-phase stator winding as well as at only one set of the three-phase stator winding (motor-generator mode). A unified and simplified mathematical treatment along with its experimental results is presented.

Static Synchronous Compensator Damping Controller Design Using Fast Output Sampling Feedback Technique

Abstract In this article, the design of a damping controller for a static synchronous compensator using a fast output sampling feedback technique is presented. The proposed technique needs only the information of locally available signals, and moreover, by this technique, a very simple controller in the form of a simple gain matrix is obtained, which is effective over a range of operating conditions. Because of these two reasons, the control system designed by the proposed technique is very easy to implement. The effectiveness of the proposed technique has been validated through detailed non-linear simulation studies on the 10-machine 39-bus New England system.

Vector control of asymmetrical six-phase synchronous motor

Abstract Vector control scheme has been well adopted for higher performance applications of AC motor. Therefore, this paper presents an extensive development and investigation of vector control scheme for asymmetrical six-phase synchronous motor in a new two-axis (M–T) coordinate system. Phasor diagram has also been developed in a simplified way, followed by its implementation technique. Analytical results have been presented for four-quadrant operation of synchronous motor, employing the developed vector control scheme. In analytical control model, common mutual leakage reactance between the two winding sets occupying same stator slot has been considered.

An Improved Power Flow Analysis Technique with STATCOM

In this paper, a simple and efficient algorithm for incorporating STATCOM losses in the load flow calculation is proposed. In this technique, both the STATCOM switching loss and the step-down transformer ohmic loss are accounted for and are calculated iteratively. To reduce the computational burden, the system load flow equations and the STATCOM equations are solved separately. The proposed algorithm has been tested on IEEE 30 bus and IEEE 57 bus power systems. Based on the results obtained on different operating conditions, the proposed algorithm has been found to possess good convergence characteristics. The influence of different factors on the convergence characteristics of the proposed algorithm has also been investigated in detail.