Jan'21
The IUP Journal of Electrical and Electronics Engineering
Focus
In a balanced or symmetrical three-phase power system, voltages and currents have the same amplitude and each has a phase difference of 120. Due to various reasons like uneven distribution of loads, unbalance occurs. In the paper, "Improving the Three-Phase Unbalance Rate of Railway System Under 2% by Three Kinds of Special Transformer Wiring", by Chien-Hsu Chen and Chin-E Lin, unbalance in the railway electric system is studied. It is shown that unbalance can be reduced to less than 2% by different traction transformer winding connections like Scott, Le-Blanc and Modified-Woodbridge. Symmetrical components-based transformer models are developed to verify the unbalance in three-phase circuit.
LiDAR, an acronym for Light Detection and Ranging, measures an object distance by emitting laser to the object and capturing the traveling time. It is a virtual perception device utilized to check the earth 's exterior surface. The last paper, "LiDAR Technology - An Overview", by S M Nazmuz Sakib, describes various aspects of LiDAR. A LiDAR system measures the time it takes for emitted light to travel to the ground and back, and the distance traveled is calculated using this time. Airborne laser scanning technology using LiDAR and its application in forest assessment and monitoring are also discussed.
Consulting Editor
Maxwell 's Equations: Road to Wave Propagation Theory
Maxwell 's equations are exceptionally compelling and effective, as they embody and symbolize an essential aspect of Electromagnetic Field (EMF) theory. Nevertheless, Maxwell 's achievement was beyond the synthesis of his four most influential equations in science, namely, Gaussian 's law for electric fields, Gaussian 's law for magnetic fields, Faraday 's law, and the Ampere-Maxwell law, or the addition of the displacement current term to Ampere 's law which was considering these expressions (or equations) in amalgamation, through which he attained his goal of developing a comprehensive theory of electromagnetism. It is that theory which elucidated the true nature of light itself and opened the eyes of the world to the full of spectrum of electromagnetic (EM) radiation. In this paper, the road to the equation of the wave, the divergent theorem is inferred very conscientiously, and is highly significant to researchers engaged in wave equations. This study is very important to researchers engaged in generating the equation for wave and eradicating the extra-terrestrial noise, which is imperative for the field of wave propagation, and which can be applied to terrestrial propagation modeling frequency band management 2.5 GHz to 60 GHz, propagation models and designs etc. Maxwell developed the first unified theory of physics, to show that electricity and magnetism are intimately connected.
Improving the Three-Phase Unbalance Rate of Railway System Under 2% by Three Kinds of Special Transformer Wiring
Unbalanced power causes loss of the propulsion motor of railway vehicles, and increase in temperature shortens the service life of electric vehicles. Not only this, it also increases the cost of electricity and maintenance. In the past, the industry focused only on methods to improve power quality such as load capacity, relay setting, and harmonic resolution. Now, they consider Three-Phase Unbalance Rate (TPUR). The paper proposes Special Transformers Wiring (STW) to improve the three unbalanced rates and provide different transformer wiring methods. According to the IEEE Committee, in the future, power companies will need to install balanced relay stations to improve three-phase unbalanced rate. The internal regulations of Taipower must be less than 4.5% (voltage unbalance rate of 2.5% and motor temperature rise of 12.5%). The derivation of the transformer "three-phase unbalance rate" model is the focus of the railway system. This study is based on the model derivation of different wiring methods to improve the heat problem caused by the three-phase unbalance and improve the service life of the train. A comparison is made with Scott, Le-Blanc and Modified-Woodbridge three wiring methods in railway system routes to improve the three-phase unbalance rate, in line with the IEEE standard of less than 2%.
LiDAR Technology - An Overview
Light Detection and Ranging (LiDAR) data has proved to be useful in recent years since it gives information, such as item height and attributes, and statistics over large regions, and it all becomes available by capturing the intensity of backscattered pulses in addition to 3D coordinates. A LiDAR may generate a 2D angle image and a 3D picture containing angle/range information. It can directly measure range in each pixel since it controls when light is emitted, allowing it to calculate range based on the Time of Flight (ToF) to and from the object in a particular pixel. If there is enough signal, a 3D picture can also have grayscale and color. Coherent LiDAR can detect velocity quite precisely. A brief introduction of airborne laser scanning technology, also known as LiDAR, and research findings on its application in forest assessment and monitoring are discussed in this paper.