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In this work is presented in a simulated environment, the analysis of the required length of conterpoise cable connected to the ground rod in a transmission line located in Maceió, Brazil, capable of avoiding the phenomenon known as back flashover, in other words, the disruptive discharges of return in the chain of insulators when subjected to standardized atmospheric discharges considering some values...
Earthing (grounding) cord-connected products creates an equipotential environment for personnel which provides protection against electric shock. The earthing scheme can be functional only, a principal safeguard, a supplementary safeguard, a reinforced safeguard, or a combination of these safeguards. The principal safeguard function returns protective conductor currents to their source and prevents...
To eliminate local corona and reduce minimal discharge distance of transmission lines, this paper analyzed expanding diameter insulation jacket for 110kV transmission line. The minimal discharge distance and its relationship with the diameter of semi-conducting and expanding diameter was calculated theoretically, finding the best size of expanding diameter and general standard of expanding diameter...
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...
After the application of IT system being described briefly, operating characteristics and constraints of IT system with the neutral conductor are expounded. The feasibility of the neutral conductor in IT system is discussed in detail. Then the reason why insulation fault in N conductor can't be diagnosed by traditional methods is explained, and the problem can be solved by the method of injecting...
“Temporary overvoltages (TOVs)” and their effects are addressed in the product safety standards for information and communication technology equipment both as one of the causes of VDR (voltage dependent resistor) fire and burst, and also as a factor in the determination of working voltages. Unlike sudden impulsive transient overvoltages, TOVs at power frequencies are due to the fault in low-voltage...
The application of high-resistance neutral grounding (HRNG) to medium-voltage systems is one of the least understood and often misapplied methods of system neutral grounding. An HRNG grounded system is the only intention ally grounded neutral grounding method suitable for industrial systems that allows normal operation (no voltage dips, no power surges, no shutdowns, minimal damage) for an indefinite...
We clarified the influence of grounding resistance on the effectiveness of lightning protection for power distribution lines with a ground wire (GW) and surge arresters (SAs) by EMTP analysis and experiments. The results indicated that power distribution lines with both a GW and SAs can increase the lightning protection level against direct hits without lowering the grounding resistance compared with...
Street lighting installations are publicly accessible electrical pieces of equipment out of the physical control of who operates/owns them. Street lighting systems are a typical case of low-voltage loads, distributed in a large area and collectively protected by the same protective device. In fault conditions, hazardous potentials may appear on the metal parts of such equipment, and expose persons...
In the United States, “grounded” and “grounding” are defined by the National Electrical Code (NEC), which is concerned with the safety of life and property.
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