The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The basic factors and general considerations in selecting the class and means of neutral grounding for synchronous generator systems connected to electrical utility systems are provided in this guide. It also provides the suggested methods and apparatus to be used to achieve the desired grounding. These guidelines apply to both large and small generators found in electrical utility systems. Definitions...
The application of neutral grounding to three-phase electrical utility systems is described in this guide. It is Part 1 of the IEEE C62.92 series of guides for neutral grounding. This guide presents basic considerations of the selection of neutral grounding parameters that will provide for the control of overvoltage and ground-fault current on all parts of three-phase electrical utility systems rated...
Electrode resistance is a typical measure of whether a buried electrode meets the design criteria of the electrode. In this context, IEC 62305 promulgates a value of 10 Ω as maximum value for adequate lightning protection. In this paper it is argued that, in addition to electrode resistance, lightning ground potential rise is another important parameter to be considered by the design engineer. This,...
Symmetrical monopolar HVDC links, based on Modular Multilevel Converters (MMCs) represent the state of the art for submarine and underground cable interconnections over long distances. MMCs exhibit significant advantages if compared to other converter topologies, such as lower losses, footprint and harmonic distortion. However, due to the use of a symmetrical monopolar arrangement, severe temporary...
Shifting medium-voltage networks to operate with the neutral grounded via a resistor or an RL circuit is the most promising approach to improving the reliability of electric power supply systems either with or without capacitive current compensating devices. The Smart Grid principles imply minimization of losses to consumers; therefore, the optimal solution for the neutral grounding mode can be reached...
This article concerns reliability assessment of an electricity distribution substation surge protection system, composed of surge arresters. For this purpose a reliability analysis is performed and also a surge protection system reliability mathematical model is suggested. Based on it mathematical formulae are worked out intended for practical calculation of proper reliability indices values. The...
Overhead and high-voltage cable lines have obtained a vast broadening nowadays in energetics. However, these types of power lines have a number of problems. Improving an insulation's durability is one of the possible solutions. In this paper, the power line of 330kV has been modeled and simulated. As an example there was selected a real electrical transmission located in the city of Saint-Petersburg,...
According to the specifications in IEEE 1894-2015, a transient process measuring device (TPMD) is developed to be used in the distribution system, and a line selection technique utilizing large pulse current is presented on this basis. When a single-phase grounding fault occurs, the distribution system is able to be instantly switched from grounding with small current to grounding with large pulse...
A surge sensitivity study of distribution transformers in rural areas of Cundinamarca — Colombia was performed. The analysis took into account the grounding resistance magnitude and the transient overvoltage injection point. Lightning overvoltages are introduced in the IEEE 13 bus system test feeder by using the EMTP-ATP program, results show that delta surge arrester configuration used to protect...
A great proportion of the extended electricity distribution network (20/0.4 kV) failures in Greece can be considered as lightning related. This paper examines the overvoltage surges, affecting crucial elements of the distribution system of Patras, Greece. Two scenarios were discussed. The first suggests that, the medium and low-voltage networks share the same grounding system and the second that,...
A key aspect in the evaluation of the lightning performance of an overhead line is the tower grounding modeling approach. It affects the insulator string overvoltages and the ground potential rise (GPR). This work aims to assess the impact of the soil model i.e. using frequency independent and frequency dependent parameters. The developed grounding system model was implemented in the EMTP-ATP program...
The paper addresses the statistical simulation of the backflashover performance of an Italian 150 kV–50 Hz mixed overhead-cable subtransmission line, focusing on direct lightning strokes to the overhead-cable transition tower. An ATP-EMTP-based Monte Carlo procedure, developed by the authors, has been applied to assess the backflashover rate (BFR) of the mixed line (ML). In addition, the procedure...
High frequency grounding impedance measurements were conducted at the test site in Huta Poreby during the summer season in 2015. The impedances seen from different locations were measured with the impedance meter AES 1002 at frequencies ranging from 100 Hz to 1 MHz. The obtained impedance vs. frequency characteristics have similar shapes. In the low-frequency range impedance values are almost constant...
This paper presents a study of lightning induced surges in railway signaling systems with the FDTD method. During an indirect lightning strike, induced surges are observed in the outdoor circuits due to electric and magnetic coupling. The induced surge currents propagate along the signal cables towards the receiving equipment in railway stations. It is found that geometry of the outdoor lines, earthing...
Aim of the paper is to investigate on the probability of a coordinated surge protective device (SPD) system to reduce the risk of failure of electrical and electronic equipment within a structure against lightning surges due to direct lightning stroke to the connected low voltage overhead lines (source of damage S3 according to IEC standard 62305). Two SPD systems are considered, namely SPD system...
The connection to ground of the negative or positive terminal of photovoltaic (PV) generators is a common practice to mitigate the effects of the potential induced degradation (PID), which is attributed to chemical reactions (ion's exchange) between the materials that constitute the PV-module during operation. Furthermore, the complex topology of a utility scale PV-plant, its dimensions and the stored...
Surge voltage on the carriage which transports along high speed train occurs frequently in the process of pantograph rising, the surge voltage is likely to cause electromagnetic interference or logical confusion to vehicle control and communication system, and even damage the vehicle-mounted components. That maybe a potential threaten for normal operation of high speed train. And the amplitude of...
Photovoltaic (PV) systems, due to their installation position, are exposed to direct and indirect lightning hits, which can damage the equipment of the system, resulting in interruption of the power supply, repair or/and replacement costs and dangers for the personnel. So, the implementation of an effective lightning protection system is a critical issue, in order to achieve safe and uninterrupted...
With spreading using of switch type arc extinguishing in 10 kV distribution network, it is necessary to study the over-current on traditional PT (potential transformer) during arc extinguishing. Firstly, the mechanism of Ferroresonance and low frequency oscillation, which is motivated by single-phase grounding and disappear during arc extinguishing, is theoretically introduced; secondly, a test platform...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.