Piece Of Electrical Equipment Research Articles

Transfer Function and Transient Response Analysis of Active Inrush Current Limiting Circuit on P-MOSFET with Equivalent RLC Series Circuit Load of Inverter

Inrush current is a transient current surge when a piece of electrical equipment is turned on. One of the solutions is a P-MOSFET-based active inrush current limiter, which will be analyzed with KiCad software to analyze the transient response graph and a Python program to analyze the transfer function graph. From the observation, the circuit could reduce the inrush current amount which was initially ranging from 12mA – 12A to below 500nA, with a very low amount of ripple (under 100nA peak-to-peak). The transfer function graph from the RLC load represents its transient response graph, and the transfer function graph of the inrush current limiter with load creates a logarithm function.
 Keywords: inrush current, P-MOSFET, transient response, transfer function, ripple

Application of condition-based maintenance for electrical generators based on statistical control charts

Condition-based maintenance involves activities that are conducted based on the equipment's performance. Continuous monitoring of equipment will ensure that it will be maintained according to a relevant activity plan. This paper proposes a maintenance framework to analyze the application of statistical control charts for condition-based maintenance of electrical generators. The proposed framework consists of four components that collaboratively determine a performance threshold for a given piece of electrical equipment. Based on the slow progression and dynamics of mechanical failures, Long Short-term Memory (LSTM) and Useful Remaining Life (URL) models were used to assist in the maintenance decision-making process. The analysis is based on detecting the dynamics of the process parameters, including vibration, noise, and temperature, based on relevant control charts. With the help of experimental methodology, failures in the performance modes and defined modes are measured. Then empirical analysis reveals how control charts respond to failure detection. The results show that X-bar consistently demonstrates failure detection capability, while R charts sometimes fail when data deviates from normality.Moreover, heat monitoring surpassed vibration and noise in failure detection, where temperature control charts successfully identified failure. The overall results support the significant role of statistical charts in decision-making regarding condition-based maintenance for electrical equipment like generators.•Application of statistical control charts for condition-based maintenance of electrical generators.•Detecting dynamics of the process parameters, including vibration, noise, and temperature, based on relevant control charts.•Long Short-term Memory (LSTM) and Useful Remaining Life (URL) models were used to assist in the maintenance decision-making process

Seismic risk analysis of electrical substations based on the network analysis method

AbstractElectrical substations are critical elements of a power grid, enabling the transmission and distribution of electric power from power generators to the end‐users. Experiences from previous earthquakes have shown that electrical substations can be damaged due to ground shaking, reducing their functionality and potentially preventing the generated electric power from reaching end‐users. To assess the seismic vulnerability of a substation, a modular quantitative assessment method is proposed. In this method, the relation between the functionality state of a substation and the damage state of its components was established through the connection matrix technique. A substation is viewed as a network system, whose topology is defined by the connections among various pieces of electrical equipment (i.e., the components), represented in the connection matrix. The maximum allowable power transmission capacity of the substation after an earthquake is adopted as the system functionality metric, which is jointly determined by the power input, transform, and output capacity of the substation. The seismic vulnerability of an electrical substation is quantified by probabilistically calculating its postearthquake functionality when exposed to various earthquake intensities using Monte Carlo sampling. Finally, the risk of substation functionality loss is quantified by integrating the seismic hazard curve with the seismic vulnerability model of the substation. Two realistic case studies on a distribution substation and a transmission substation, with the same equipment configuration but different power delivery paths, were performed using the proposed method. Furthermore, a sensitivity analysis regarding the equipment fragility parameters is conducted, providing a risk‐informed basis for improving the seismic performance of the substation system.

A Graphical Approach to Incident Energy Analysis

The goal of an incident energy analysis is to determine the largest incident energy that a worker could be exposed to at a piece of electrical equipment. This is most commonly done using the IEEE 1584 method. It is a common observation when performing this analysis that minor variations in fault current can result in large changes in a protective device's operating time and the resulting incident energy. This would not be a problem if it was possible to remove all errors from the bolted fault calculation and the arcing fault calculation. Unfortunately, the arcing fault current calculation has some margin of error and the data used in arc flash models are often estimated. A graphical approach to determining the incident energy circumvents these problems and ensures that the worst-case incident energy is determined. This graphical approach is derived from graphs of incident energy based on protective device time–current curves. An examination of the resultant graphs reveals a few maximums in the incident energy curve. These maximums are caused by the protective devices curve, the minimum and maximum arcing fault currents, and any time limitations that are applied. As a result, the locations of these maximums are easily predicted allowing the maximum incident energy to be determined by performing the IEEE 1584 calculation at a few key current values.

Power Transformer Differential Protection Based on Clarke's Transform and Fuzzy Systems

The power transformer is a piece of electrical equipment that needs continuous monitoring and fast protection since it is very expensive and an essential element for a power system to perform effectively. The most common protection technique used is the percentage differential logic, which provides discrimination between an internal fault and different operating conditions. Unfortunately, there are some operating conditions of power transformers that can affect the protection behavior and the power system stability. This paper proposes the development of a new algorithm to improve the differential protection performance by using fuzzy logic and Clarke's transform. An electrical power system was modeled using Alternative Transients Program (ATP) software to obtain the operational conditions and fault situations needed to test the algorithm developed. The results were compared to a commercial relay for validation, showing the advantages of the new method.

Capacitor Application Issues

Capacitors provide well-known benefits to electric power systems. These benefits include power factor correction, voltage support, release of system capacity, and reduced system losses. As with any piece of electrical equipment, there are a number of application issues that engineers need to be aware of. These issues range from the very basic to the very complex. Most of these application issues can be, and have been, the subject of their own detailed technical papers. This paper does not get into rigorous detail but rather discusses these issues with the goal of making the reader aware of many of the traps one can fall into when applying capacitors. The application issues are addressed based on the authors' experiences working in various capacities (performing power system measurements and studies, performing engineering service failure investigations, advising capacitor sales personnel, consulting with end users, and building custom capacitor banks), thus seeing these problems from many different angles.

Ensuring that electrical equipment is safe for its intended use

The Occupational Safety and Health Administration (OSHA) regulations, the National Electrical Code (NEC), and several other nationally recognized standards and recommended practices indicate that electrical equipment must be inspected, tested, and evaluated to ensure that it is essentially free of hazards. This article guides the reader toward methods that will ensure that electrical equipment meets the safety intention of present day regulations, codes, and standards. The authors have experienced the situation where an electrical inspector, or a safety inspector, says that a particular piece of electrical equipment cannot be used because it does not have a label stating that it is listed by an nationally recognised testing laboratory (NRTL). The inspector's argument is that without such a label, he or she does not know if the equipment is safe for its intended use. The authors agree that one should try to purchase equipment with an NRTL label. But, if that is not possible, there are other acceptable ways to evaluate the safety of equipment and installations. OSHA allows two alternatives to listing and labeling. One involves the use of another federal agency, state, municipal, or other local authority responsible for enforcing occupational safety requirements. The other involves the use of manufacturer's test data, which the employer must keep.

Characterization of Extremely Low Frequency Magnetic Field Exposures of Office Workers

Abstract The purpose of this study is to present results of an extremely low frequency magnetic field exposure assessment performed in a large office building environment. The extremely low frequency magnetic field assessment strategy included an evaluation of full-shift personal exposure for building occupants, a determination of average work area magnetic fields, and magnetic field characterizations of sources within each work area. An employee questionnaire regarding daily utilization patterns of workplace magnetic field sources was also used to help interpret exposure information. Magnetic field exposures were determined using EMDEX magnetic field exposure meters. For personal magnetic field characterization, each participant wore the monitor for a full shift, and office area magnetic fields were determined as the average of five equally spaced measurements. In situ source characterization included measuring magnetic fields at 30 and 50 cm from pieces of electrical equipment. 259 employees in the buil...

Placing a 20 000-hp Motor in Service

Placing major pieces of electrical equipment in service is aided by a systematic approach to selection, specification, inspection, shipment, storage, check-out, and run-in. This paper describes the detailed planning that helped assure a successful start-up of a large electrical motor. Although a specific installation is described, it will be found that many of the procedures will be generally applicable.

The hazard of electrocution during patient monitoring.

Summary The ever-present hazard in patient monitoring is electrocution resulting in ventricular fibrillation. Fire and explosion hazards are possibilities but seem to be very remote. Iatrogenic electrocution can occur when: (a) more than one piece of electrical equipment is connected to the patient. (b) the distal end of an intracardiac electrode is handled. (c) pericardiocentesis is carried out with ECG monitoring, Under these circumstances, small currents, of the order of 100-200 μA, may cause ventricular fibrillation. There is evidence that the ventricular fibrillation threshold is substantially lowered by anoxia and acidosis but it seems to be unaffected by barbiturate anaesthesia. This paper suggests that the physician or surgeon should understand the risks but may need the expert advice of an electrical engineer. Ventricular fibrillation which has occurred under these circumstances requires careful, expert investigation to establish whether or not it was electrically induced.

A Method for Detecting the Ionization Point on Electrical Apparatus

WHEN any part of the air path included in the insulating circuit of a piece of electrical equipment is overstressed, ionization occurs. The critical value of voltage is a function of the nature of the remainder of the dielectric circuit, the manner of use, surface conditions, the proximity of grounded conducting bodies, the temperature, and in some cases, the relative humidity. Ionization in air causes the formation of small quantities of ozone and oxides of nitrogen. The presence of ozone leads to accelerated aging of insulating materials, especially organic materials such as varnished cambric and paper.