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The following topics were dealt with: power system protection; transformer relays protection; induction motors; momentary service interruptions; ship-wide area differential protection scheme; battery charger; zero-voltage switching resonant converter; photovoltaic arrays; load forecasting; switchgear; power distribution reliability; electronic ballast; fluorescent lamps; power circuit breakers; and...
This response to the paper by Mr. Donald W. Zipse entitled "equipotential planes, a figment of the imagination" comes from a power systems grounding perspective. Mr. Zipse's paper has presented opinions in opposition to the use of equipotential planes, and the multigrounded neutral distribution system. This response focuses on the areas of weakness in the paper and demonstrate that many...
The high-frequency resonant converter has numerous well-known advantages over traditional hard switching converters. The most important advantage is that it offers a lower switching loss and a higher power density. Additionally, the soft-switching current waveform characterizes lower electromagnetic interference (EMI). This study presents the circuit configuration with the least components to realize...
An innovative method is proposed where charging current can be measured and grounding resistors sized without staging a fault. Overvoltages have caused damage to equipment and voltage transformer fuse blowing an ungrounded 4.8 kV delta distribution system. Three causes are suspected: single-line-to-ground faults, multiple restrikes and ferroresonance. The first is the most likely. The existence of...
Multiple grounded neutral systems require that, on most land-based AC current service installations, the bonding conductor used to connect the non-current-carrying metal parts of equipment, the system grounded conductor (neutral), and the grounding electrodes be bonded together at the service entrance box. Users, thus, share their ground with the serving utility's neutral ground. This interconnection,...
In the meeting or education, the computer projectors are increasingly popular. Developing a low cost, high efficient and high luminance lamp is the key to improve its pressure and increase its market share and penetration. The ultra-high performance lamps (UHP) are developed from high-intensity discharge (HID) technologies. The luminance of ultra-high performance lamps can exceed 9,000 only with 150...
TN-island grounding system is an effective way to both protect persons from shock hazard in installations with contained demand load, and greatly limit electrical interferences among systems. This distribution system, which utilizes separation transformers, grounded on the secondary sides, allows one to supply loads broken into "islands" as independent electrical areas. TN-island fits best...
This paper provides a simplified approach on various considerations to estimate the steady-state voltage drop in low voltage AC power distribution systems. Apart from other parameters, 'load center distance' is critical in most of the cases to determine realistically the voltage drop. This aspect is therefore covered in detail by developing equations to compute the load center distance for various...
Modeling of the electric system "architecture" aims to achieve performances of safety, maintenance, operation and reliability. The paper discusses about the criteria in designing special cases, as roadway tunnels, that need a structured architecture complying with electrical loads extensively distributed and with installation requirements proper to external stresses hazard as fire hazard...
The distribution system configuration can be modified using line switches. This approach enables the loading of line segments and distribution feeders to be adjusted to obtain the load balance and enhance the system performance due to loss minimization resulting from the presented generic switching actions. This paper develops the optimal switching actions for the 22.8 KV underground distribution...
A significant portion of electric utility operating expense comes from the energy production. In order to minimize the cost, unit commitment (UC) scheduling is an important tool to properly assign generation units to accommodate the forecasted system demand. The short-term load forecast is a prerequisite for UC planning. The projected load up to 7 days ahead is important for the reconfiguration of...
Various misinterpretations of a utility's reliability performance by non-utility personnel can significantly compromise the reliable design and operation of industrial and commercial power systems. The methodology used to assess the historical reliability performance of utility electric distribution systems is outlined. Included is an overview of the process used to collect and organize the required...
This paper presents an efficient, small-sized, and cost-effective single-switch power-factor-correction (PFC) scheme for high-frequency electronic ballasts. The circuit topology originates from the integration of a buck-boost power-factor-correction converter and a class-E electronic ballast. Only one active power switch is commonly used by both power stages to save the cost of active switches and...
The benefits in performance (sensitivity and speed), reliability (security, selectivity, and dependability), availability, efficiency, economics, safety, compatibility, and capabilities of microprocessor multifunction protective relaying (MMPR) technology over the previous existing technologies, namely electromechanical and solid-state, are explored. The suggested typical values, quality measurements,...
In a scenario of worldwide globalization, a comparative analysis of international electrical safety standards with an understanding of their similarities and differences will emphasize the range of definition, the "meaning" and organization of the rule systems. To study the other "way" compels a better understanding of one's own "way" by imparting information of "different"...
Measurements of pulsating voltage taken by an expert using a digital multimeter did not represent the magnitude of voltage or the total energy. Some experts have used the same type meter without completely explaining or showing what portion of the energy had not been recorded. A heuristic approach of showing what the voltage signature probably looked like using a signal generator and a digital storage...
This paper provides an introduction to the new industrial systems chapter of the Emerald Book. The basic concepts of the high frequency model, noise modes, field coupling, and shielding are explained. These concepts are then applied to the techniques of bonding, segregation and filtering to explain recommended practices for control cabinet design
The purpose of this paper is to point out deficiencies in both the arguments presented and the opinions expressed by Mr. Donald W. Zipse in the paper entitled "equipotential planes, a figment of the imagination". In this paper the author opines that equipotential planes are dangerous, but presents no theoretical basis or creditable evidence to support this opinion. The author implies that...
C4ISR - command, control, communications, computers, intelligence, surveillance and reconnaissance - a convergence of critical functions that together define a mission-critical facility. Each function is very important, and the loss of any one results in diminished capacity for real-time generation of tactics, strategy, logistics and plan implementation. The loss of the entire mission-critical C4ISR...
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