Carpathian Journal of Electrical Engineering

17-24

Authors: Ovidiu COSMA

This article proposes a steganography method that uses all three components of an image in the RGB color space to store secret data. The order in which the image pixels are processed is not given by their position within the image, but by their visual significance. In order to ensure the greatest possible embedding capacity, the image container is traversed in several passes, each expanding its capacity.

37-46

Authors: Ovidiu COSMA

The edge detection techniques have to compromise between sensitivity and noise. In order for the main contours to be uninterrupted, the level of sensitivity has to be raised, which however has the negative effect of producing a multitude of insignificant contours (noise). This article proposes a method of removing this noise, which acts directly on the binary representation of the image contours.

59-72

Authors: Lenin KANAGASABAI

In this paper, Improved Moth-Flame Optimization (IMFO) algorithm has been proposed for solving Reactive power problem. Navigation method of moths in nature called transverse orientation is the key inspiration of the moth-flame algorithm (MFO). By maintaining a fixed angle with respect to the moon, Moths fly in the night and it’s an effective mechanism for moths travelling in a straight line for long distances. Due to very slow convergence and poor precision, an improved version of MFO algorithm based on Levy-flight strategy has been proposed to solve the reactive power problem. The diversity of the population can be increased by Levy-flight to overcome premature convergence in order to reach the global optimal solution. This methodology improves the trade-off between exploration and exploitation ability of moth-flame algorithm (MFO).The proposed Improved Moth-Flame Optimization (IMFO) algorithm has been tested in standard IEEE 30,57,118 bus test systems and simulation results show clearly about the better performance of the proposed algorithm in reducing the real power loss with control variables within the limits.

15-19

Authors: Alexandru HOTEA, Sorin SAVA, Radu TIRNOVAN

Power transformers are the most important and expensive equipment from the electricity transmission system, so it is very important to know the real state of health of such equipment in every moment. De-energizing the power transformer accidentally due to internal defects can generate high costs. Annual maintenance proved to be ineffective in many cases to determine the internal condition of the equipment degradation due to faults rapidly evolving. An On-line Monitoring System for Power Transformers help real-time condition assessment and to detect errors early enough to take action to eliminate or minimize them. After abnormality detected, it is still important to perform full diagnostic tests to determine the exact condition of the equipment. On-line monitoring systems can help increase the level of availability and reliability of power transformers and lower costs of accidental interruption. This paper presents cases studies on several power transformers equipped with on-line monitoring systems from Transelectrica substation.

31-38

Authors: Oliviu MATEI, Ioan VLAD, Robert HEB, Alexandru MOGA, Otto SZIKA, Ovidiu COSMA

The article presents some experiences with the smart glasses developed by Epson, namely Movrio BT-200, BT-300 and BT-2000. We conclude that they are on the right track, good devices, however, are still in an incipient, before the market stage and need a lot of technical (both hardware and software) improvements to be up to the needs of the real market.

49-60

Authors: Jacob TSADO, Olabisi AKINWOLE, Gbenga OLARINOYE, Sadiq AHMAD

This research work investigated the electrical energy efficiency improvement and cost saving potentials for automobile assembly plant; a case of Peugeot Automobile Nigeria Limited. The study identified lighting system as a major source through which energy is being wasted, hence efficient energy saving lighting systems are being proffered; also saving accrued were determined to justify their deployment. In the course of this work, an energy saving calculating tool was developed to calculate energy saving capabilities using energy efficient lamps. With ample devotion to the implementation of the recommendations made, the cost of energy per car will be drastically reduced while profits are also made simultaneously. In all, more cars will be produced thus translating to more employment opportunities in the industry.