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Not all 'short circuits' are 'dead-shorts' -i.e. the resistance between the two conductors (or a conductor and earth) is not necessarily zero ohms -especially when the insulation between them has not completely broken down. The actual resistance is called the 'fault resistance'.
What else can I help you with?
What is leakage resistance?
leakage resistance of a resister is type of fault which occurs at a specific voltage across the resister which are undertesting.
The value of resistance of an short circuit?
The value of resistance when there is a short circuit varies depending on the nature of the fault, but it could be fractionally above zero or higher.
How designing stabilizing resistor in restricted earth fault relay?
To determine the value of Stabilizing resistor Rs = Vs/Is = If(Rct +2Rl)/Is Where, Rs = resistance value of the stabilizing resistor Vs = voltage at which the relay will operate Is = current flowing through the stabilizing resitor and the relay If = maximum secondary fault current magnitude Rct = internal resistance of the current transformer Rl = resistance of attached wire leads
Why is sensitive earth fault protection required?
Sensitive Earth Fault protection is required to either to alarm or trip the faulted circuit. It is usually used for resistance grounded or ungrounded systems; where first earth fault doesn't interrupt supply. It is also used on long overhead lines (even solidly grounded systems) where earth fault currents can be significantly low.
What is the difference between neutral earthing resistance and solid earth?
The star point of a primary*-transformer's secondary winding is frequently connected to earth via an impedance, in order to limit the return current in the event of an earth fault close to the transformer. The impedance may be a resistor or an inductor, (choke) depending on the nature of the earth return. In general, if the earth resistance is low, then resistive earthing is used; if the earth resistance is high, then inductive earthing is used.(*e.g. 33/11 kV)For resistive earthing, the transformer secondary's star point is often connected to the centre electrode of a galvanized-steel tank which is solidly earthed. The tank is then filled with water, and it is the resistance of the water that provides the required resistance to earth. The actual resistance of the water is modified to the desired value by dissolving sodium carbonate into the water while measuring its resistance. The solution has a negative temperature coefficient of resistance, which means that, in the event of an earth fault, as the fault current increases, the increasing temperature causes the resistance of the water to decrease, thus accelerating the response time of the protective system.
What is a bad connection in an electrical circuit called?
"A wiring fault" which - depending on the actual behavior of the bad connection - might also be described as "an intermittent fault", "a high resistance fault", or a combination of all three terms. For example: "An intermittent, high resistance wiring fault".
Why resistance is neglected for fault finding?
A fault can be resistive in nature, and the amount of resistance in the fault is unpredictable. It is unusual for a fault to be inductive or capacitive, so a typical method is to determine the impedance to the fault, and compare only the inductive part of this to the inductive part of the line impedance.
How frictional resistance along a fault affect the force released during an earthquake?
Higher frictional resistance along a fault can inhibit the fault from slipping smoothly, causing stress to accumulate over time. When this stress is eventually released as an earthquake, the force released can be higher if the resistance was greater. Conversely, lower frictional resistance can allow the fault to slip more easily, potentially leading to a lower force released during an earthquake.
How do you locate fault using whetstone bridge?
To locate a fault using a Wheatstone bridge, you first connect the bridge to the circuit where the fault is suspected. By adjusting the bridge until it is balanced (indicating zero voltage difference across the galvanometer), you can determine the resistance values in the circuit. If the bridge remains unbalanced, the difference in resistance can help identify the location of the fault by comparing with known resistance values. The point where the fault occurs can often be inferred from the changes in resistance readings throughout the circuit.
What is leakage resistance?
leakage resistance of a resister is type of fault which occurs at a specific voltage across the resister which are undertesting.
What is a Locked Fault?
A locked fault is a fault that is not slipping because frictional resistance on the fault is greater than the shear stress across the fault (it is stuck). Such faults may store strain for extended periods that is eventually released in an earthquake when frictional resistance is overcome.
Why the high resistance earth fault in the appliance increase the risk of electric shock when using appliance in earth situation?
If the earth connection has a high resistance it is not capable of acting as a true earth. For example, the high resistance might mean that the fuse or circuit-breaker will fail to operate when there is a fault.
The value of resistance of an short circuit?
The value of resistance when there is a short circuit varies depending on the nature of the fault, but it could be fractionally above zero or higher.
Using blavier test to check for cable faults?
This is use to locate the ground fault of a single cable. This test is performed with the aid of a low voltage supply with an ammeter or voltmeter. In this test the resistance between one end of the cable C1 and the earth is first measured with the other end, C2 isolated to earth and then with the C2 earthed. Let the two readings be represented by R1 and R2 rep! If r1 and r2 are the conductor resistance of the length of cable at C2 to fault and at C1 to fault rep!, and "r" is the resistance of the fault to earth
Why neutral of generator is resistance grounded and neutral of motor is reactance grounded?
You can use resistance or reactance grounding on generators and motors. My understanding is resistance grounding is often used to limit ground fault currents to a few amperes, while reactance grounding will limit fault current to less than the three phase fault current. If reactance grounding is used to limit fault current o very little (like resistance grounding), transient overvoltage problems can occur.
What is the purpose of earth connection in a domestic ring circuit?
To provide a low-resistance return in the event of a earth-fault current occurring anywhere in the circuit. The requirement for a low-resistance return is to ensure the resulting fault current causes the relevant protective device to disconnect the faulty circuit.
What is a phase to phase fault?
Its is the condition when two different phases directly comes in contact with out any load or resistance.
