In this paper, a neural network controlled DSTATCOM (Distribution Static Compensator) using dSPACE processor is implemented for power quality improvement in a three-phase four-wire distribution system. A three-leg VSC (Voltage Source Converter) based DSTATCOM with a zig-zag transformer is used for the compensation of reactive power for voltage regulation or for power factor correction along with load balancing, elimination of harmonics currents and neutral current compensation at the point of common coupling (PCC). The Adaline (adaptive linear element) based neural network is used to implement the control scheme of the VSC. This technique gives similar performance as that of other control techniques, but it is simple to implement and has a fast response and gives nearly zero phase shift. The zig-zag transformer is used for providing a path to the zero sequence current in a three-phase four-wire distribution system. This reduces the complexity and also cost of the DSTATCOM system. The performance of the proposed DSTATCOM system is validated through simulations using MATLAB software with its Simulink and Power System Blockset (PSB) toolboxes and hardware implementation.

In this study, two simple methods for the steady‐state analysis of self‐excited induction generators (SEIGs) are proposed. These methods neither require lengthy mathematical derivations nor any advanced optimisation techniques to solve the equivalent circuit of SEIGs. First method involves a simple linear search algorithm and the second method employs a binary search algorithm to find the operating frequency at any given rotor speed, leading to the performance predetermination of SEIGs. To start the search techniques, a systematic approach has been formulated for fixing the boundary values required for the unknown pu frequency. The efficacy of the proposed methods has been demonstrated by presenting the predetermined performance characteristics of a three‐phase, 230 V, four‐pole, 50 Hz SEIG. The same SEIG was also tested in the laboratory using a DC motor as the prime mover. The closeness observed between the predetermined values and the experimental results further confirms the validity of the search algorithms. It has also been shown that the proposed methods can be extended with the same simplicity, for carrying out the performance predetermination of the short‐shunt configuration of SEIGs, used for obtaining improved voltage regulation with lagging power factor loads.

No abstract

Increasing power demand forces the development of the high‐rated power transformers. In a transformer, petroleum‐based mineral oil is used as insulation currently. Transformer oil (TO) produces environmental and health issues because it is nonbiodegradable. The availability of petroleum products is decreasing in the present century. So it encourages researchers to find potential replacements for them. In this work, two natural ester oils (rice bran oil and corn oil) were taken up for investigation to find their suitability for use in transformers. Aging analysis was performed on the TO and natural esters. For this, properties like breakdown voltage, flash point, fire point, viscosity, acidity, resistivity, and loss factor of the natural esters were considered. From the investigations, it was evident that rice bran and corn oil have the ability to be used as alternatives for TO. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

In this paper, a 4-leg VSC (voltage source converter) based DSTATCOM (Distribution Static Compensator) is used for the load compensation and neutral current compensation in 3phase 4-wire distribution system. For extracting the reference source currents, Instantaneous Symmetrical Component Theory (ISCT) based control algorithm is modified for voltage regulation and used with indirect current control technique for controlling the DSTATCOM currents. The DSTATCOM is controlled for power factor correction and voltage regulation at PCC (point of common coupling). Simulations are performed for various load conditions such as a reactive linear load, an unbalanced load and a non-linear load in Power Factor Correction (PFC) mode and in Zero Voltage Regulation (ZVR) mode in MATLAB environment using SIMULINK and Sim Power System (SPS) toolbox.