Serwis Infona wykorzystuje pliki cookies (ciasteczka). Są to wartości tekstowe, zapamiętywane przez przeglądarkę na urządzeniu użytkownika. Nasz serwis ma dostęp do tych wartości oraz wykorzystuje je do zapamiętania danych dotyczących użytkownika, takich jak np. ustawienia (typu widok ekranu, wybór języka interfejsu), zapamiętanie zalogowania. Korzystanie z serwisu Infona oznacza zgodę na zapis informacji i ich wykorzystanie dla celów korzytania z serwisu. Więcej informacji można znaleźć w Polityce prywatności oraz Regulaminie serwisu. Zamknięcie tego okienka potwierdza zapoznanie się z informacją o plikach cookies, akceptację polityki prywatności i regulaminu oraz sposobu wykorzystywania plików cookies w serwisie. Możesz zmienić ustawienia obsługi cookies w swojej przeglądarce.
Theoretically, the shape of Neutral to earth voltage (NTEV) on the commercial building is normally imitating to the neutral current profile. However, in real cases condition, the shape of waveform is different due to the grounding system influenced by the frequency variation. The frequency variation on the grounding system typically can be allocated into two modes of frequency; lower and higher frequencies...
The earth grounding (EGR) computation model contained in normative acts has multiple nonlinearities and functions with implicit definitions. In addition, through the values indicated for the utilization coefficients, the designers are oriented towards relatively large distances between electrodes and no optimal criteria are defined. In earlier works, the authors have realized nomograms in order to...
In grounding system design, there are many parameters that affect touch voltage, step voltage, and grid resistance such as depth of grid, mesh size, number of rod, length of rod, size of buried conductor, etc. This research simulated effect of mesh size, number of rod, and length of rod, where 3 design models were created. Model 1 using 4 rods with length per rod 3m and mesh size 20 × 20m, model 2...
This paper presents a study of the lightning performance of subtransmission lines located in high ground flash density areas according to the design of the grounding systems. Analysis of the behavior of 69 kV and 138 kV lines under direct lightning strokes is performed for grounding systems dimensioned based on a fixed value of the low frequency resistance established by Brazilian regulations, and...
The paper deals with the protective relaying of MV rings recently introduced by e-distribuzione, the largest Italian Distribution System Operator (DSO). The paper refers to an existing MV distribution system which includes a loop line. Attention is focused on Cross-Country Faults (CCFs), i.e. two Line-to-Ground Faults simultaneously occurring in two different phases at different locations. A large...
In previous papers, the authors have resumed the earth grounding dimensioning with the intend to propose optimum criteria and to simplifying the design procedure. Five general characteristic sizes for the earth grounding have been proposed that may be in as many objective functions. Of these, the footprint area, the total metallic mass and the earth grounding volume have already been approached with...
One of the methods that can be applied to improve the lightning performance of overhead power distribution lines is the use of shield wires. Although the effectiveness of this measure against direct strokes is quite limited unless the shield wire is grounded at every pole, the ground resistances are low, and the line has sufficient CFO between the ground lead and the phase conductors, the line performance...
External grounding grid is an effective measure to reduce grounding resistance of grounding grid. In order to meet the requirements of the grounding resistance in the most economical way, it is important to determine the distance and the area of the external grounding grid. Generally speaking, when the area is larger, the grounding resistance is smaller. When the distance of the external grounding...
To implement the practicality for fault diagnosis methods of medium-scale grounding grid, fault diagnosis model was established combining electrical network theory with sensitivity analysis in this paper. By simulation analysis of fault diagnosis, a new method which is used to select the node pairs to calculate the corrosion situation of grounding grid was presented. Based on this method, the fault...
This paper deals with tunnel installations of extra high voltage (EHV) power cables. Cross-bonding of the screens remains the usual earthing arrangements of cable systems, if their extension is greater than 1,5 km approximately. Such EHV cable systems need a functional earthing along the route in correspondence of each major section, at the sending and at the receiving ends. Given the difficulties...
Rijeka refinery has built in year 2010. new hidrocracker complex unit as a part of refinery modernization project. This was time when complete new approach in term modern communication protocols was introduced in a field of instrumentation equipment communication. Protocol name is FOUNDATION Fieldbus which by very common definition represent an all-digital, serial, two-way communications system that...
One of the technical problems in the construction of overhead lines 500 kV EHV transmission system Jawa-Bali Crossing is lightning disturbance. The most dominant problem is the height of the crossing tower (376 m) and high density of lightning strikes at the tower site. The potential disruption caused by lightning in the tower leads to insulator flashover on towers that can cause a loss of power flow...
This paper deals with the calculation of ground resistance, surface voltage, touch voltage and step voltage, to mesh with horizontal wires arranged in different angles. The mathematical modeling is based on the method proposed by Heppe, which allows obtaining the grounding parameters for soil stratified in two layers. Moreover, the results obtained by the Variable Currents Method (VCM) have been compared...
The article shows a possibility to measure the instant value of the consumed current in electrical devices or in branches of the electric power grid, without specialized sensors. As it is demonstrated, in some types of electrical networks the neutral conductor could be used as a current sensing device and as an energy source. The measuring of the voltage difference between the neutral conductor and...
The possibility to measure the instant current consumption of electrical devices or in branches of the electrical network, without specialized sensors, was evaluated. As it will be shown below, in some types of electrical networks the neutral conductor could be used as a current sensing device. Reading of the voltage difference between the neutral conductor and the protective conductor can supply...
This paper is an overview of the different types of grounding, bonding and alarming systems available throughout the world. There has been much confusion and discussion regarding the preferred method of grounding and bonding of power system on board vessels such as pleasure crafts, cargo and naval vessels. This paper will discuss the pros, cons, advantages and disadvantages of each method. It will...
There is generally an absence of a methodology that explains the logic behind the design of the lightning protection, noise control and grounding system for a telecommunication facility. Common types of telecommunications sites that require grounding include radio sites, roof mounted cabinets or shelters, ground mounted cabinets and shelters, satellite sites, data centers, cable chambers and central...
This paper presents an alternative methodology for the grounding resistance calculation of vertical electrode arrays through a computational algorithm. This algorithm was developed based on the fundamental equations for the self and mutual resistance between grounding rods calculation being it's result confronted with the a model based on the finite element method (FEM) and the formulas found in the...
Equipotentiality is one means of preventing electric shock. Grounding is a specific kind of equipotentiality. For most power distribution systems, the resistance of the grounding circuit in an electrical product is critical to establishing equipotentiality. This paper explains equipotentiality and how it provides protection against electric shock. This paper also describes the grounding circuit for...
A connection between a phase conductor and the ground in MV networks is called earth fault. The fault current in this case does not depend on the point of the fault, but only on the total capacity (size) of a network. Distribution system operator (DSO) sometimes needs to operate the large network which means operating of the network with big capacitive current (in Czech Republic more than 800A). This...
Podaj zakres dat dla filtrowania wyświetlonych wyników. Możesz podać datę początkową, końcową lub obie daty. Daty możesz wpisać ręcznie lub wybrać za pomocą kalendarza.