Mell What is through fault stability?
In practice, this is difficult to achieve – especially for very large through faults, due to the non-ideal nature of the current transformers used to measure the currents. The term used to specify the system’s ability to cope with these imperfections is called Through-fault Stability.
Why are adjacent zones made to overlap?
Protective relay engineers keep utility grids and equipment safe from faults and system unbalances by dividing the grid into zones, each with a unique protection scheme. Overlapping zones provide backup protection. Notice that zones overlap each other to provide backup protection should a primary zone fail.
How do you find maximum fault current?
Fault current calculations are based on Ohm’s Law (V=I×R). To determine the maximum current available at any given point in a distribution system, the equation is rearranged to solve for current (I=V÷R).
Which reactance value is maximum during fault?
short circuit current
During the first few cycles of fault current the reactance is least and magnitude of short circuit current is highest….Table for selecting asymmetrical peak value.
| RMS Value of Short circuit current | cosΦ | n |
|---|---|---|
| I ≤ 5 kA | 0.7 | 1.5 |
| 5kA | 0.5 | 1.7 |
| 10kA | 0.3 | 2 |
| 20kA | 0.25 | 2.1 |
What is the advantage of overlapping zone?
Overlapping Zone of Power System: Overlapping Zones are having powerful advantage; If our power system does not contain overlapping in the protective zone means, then the failure occurs in the equipment will not lie in any one of the zones and hence no circuit breaker would be tripped.
What kind of fault is considered through fault?
Two kind of through fault is considered as through fault. One is External short circuit and another one is overload condition. External short circuit: The short circuit occurs between the two phase or more phase for several hundred meters. The line fault reflects in the power generator.
When is a short circuit called through fault?
External short circuit: The short circuit occurs between the two phase or more phase for several hundred meters. The line fault reflects in the power generator. In this, from the generator point of view this short circuit fault is called through fault. Overloading: Overloading means the power sources delivers excessive current.
What is through fault in a power transformer?
PRELIMINARY In the power transformer protection, through-fault is the system fault that are external to the transformer protection zone. It is a well known concept that the zone of the protection in transformer differential relay will be defined by the location of the CTs secondaries.
What does ” through no fault of her / my etc own ” mean?
FAULT/BE somebody’S FAULTused to say that something bad that happened to someone was not caused by them Through no fault of our own we are currently two players short. → fault Examples from the Corpus through no fault of her/my etc own • In my opinion Anna acted more childishly but through no fault of her own.