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How is restricted earth fault called so how is it restricted?
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A Restricted Earth Fault (REF) refers to a method of fault protection that is applied to electrical system units, such as Transformers or generators, that is more sensitive than the method known as Differential Protection (DP).
An REF relay works by measuring the actual current flowing to earth from the frame of the unit. If that current exceeds a certain preset maximum value of milliamps (mA) then the relay will trip to cut off the power supply to the unit.
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REF protection is applied on transformers in order to detect ground faults on a given winding more sensitively than when only using differential protection.
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Differential Protection is commonly used to protect the windings of a transformer by comparing the current in the power supply's neutral wire with the current in the phase wire. If the currents are equal then the DP Relay will not operate. If there is a current imbalance then the DP Relay operates.
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REF and DP protection devices operate in similar ways to a GFCI or RCD device, which combines both REF and DP functions inside the one single device.
For more information about GFCIs and RCDs, please see the answer to the Related Question shown below.
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What causes cracks in the earth's crust?
The crust is the thinnest part on the Earth.
What is the long crack that forms as two tectonic plates move apart?
Itis called a rift.
Why are San Francisco and the Bay area at risk from a powerful earthquake?
San Francisco has been built on a fault line called the San Andreas Fault. It is a fracture in the crust of the Earth. San Francisco sits on the edge of the pacific tectonic plate. The pacific tectonic plate collides with the North American tectonic plate, causing earthquakes. San Francisco also has soft soils so it's very easy for an earthquake to happen that causes bad damage.
What is dzone depletion?
=dzone depletion is when the layer of the earth is losing pressure and getting colder and it is not good for the earth becauase the layers of the earth will be gone and this is our fault because we are poluting the air by the gas from cars and fire so we should stop doing this.this can make the world poluted so please help.=
Is the alpine fault a transform fault?
The Alpine Fault is a geological right-lateral strike-slip fault. It forms a transform boundary, so yes.
What is the difference between balanced earth fault and restricted earth fault?
There is such a thing as a three phase to earth fault, so maybe this is what you mean by a "balanced earth fault". I don't believe any earth or ground currents would flow in this case. A restricted earth fault is a typical phase to earth fault, where the zone of protection is restricted to a specific area, such as around a transformer. "Restricted" is referring to the protection method, not what is actually going on with the currents and voltages.
What types of fault is formed when plates diverge or pull apart?
Tension in Earth's crust pulls rock apart, causing hanging walls. In a normal fault, the fault is at an angle, so one block of rock lies above the fault while the other block lies below the fault. The block of rock that lies above is called the hanging wall. The rock that lies below is called the footwall.
What kind of fault happens under the ocean?
the answer is an earthquake because the plates move so suddenly it makes the earth shake so therefore it would be called an earthquake!
What type of fault is formed when plates diverge or apart?
Tension in Earth's crust pulls rock apart, causing hanging walls. In a normal fault, the fault is at an angle, so one block of rock lies above the fault while the other block lies below the fault. The block of rock that lies above is called the hanging wall. The rock that lies below is called the footwall.
How you using ref relay in transformer?
an REF relay (restricted earth fault) is used to provide ground fault protection for a transformer. Its' operation is limited by CTs starred towards the transformer (usually on the transformer bushings or in breakers used to isolate the transformer), so it will only operate for transformer related faults. Because of this, it can be set to operate very quickly.
Why phase fault relays are having higher settings and more plug positions while earth fault relays are having lower settings and usually only two plug positions?
phase fault relay are having higher settings because the magnitude of phase fault currents are not so much higher as earth fault currents.hence in order to prevent any damage to the system,the earth faults should vanish as quickly as possible
What causes cracks in the earth's crust?
The crust is the thinnest part on the Earth.
Why does san Andreas get so many earth quakes?
It gets so many Earth Quakes because it is under a fault line. Plates under the Earth's surface rub against each other and create Earth Quakes.
Which fault occurs when the hanging wall moves down relative to the foot wall?
Actually the first one is right! In my science book its clearly says :normal fault, the fault is at an angle so one block of rock lies above the fault while the other fault lies below the fault. When movement occurs along a normal fault, the hanging wall slips downward. sorry Smallvillegirl... SO THE ANSWER IS NORMAL FAULTSActually, that's wrong. I have the same crossword puzzle whoever answered the question, and it was assigned for homework, and if number 6 across is shearing, number 5 down would have to be reverse. It is reverse fault.=SmallvilleGrl=Old Answer:The answer to this question is easy! Unless you don't know your Earth Science of course! There are three different types of faults:Normal Faults, Reverse Faults, and Strike-slip Faults.A strike-slip fault(or a latteral fault) moves in opposition of each other.A reverse fault is when the hanging wall moves upward caused by compression.A normal fault is when the hanging wall moves downward caused by tension.So there you have it! The answer to your question is obviously a NORMAL FAULT!!!!!If you need any more answers' about Earth Science post some more questions and I'll answer them for ya!!!!!sincerely,~Anonymous~
When the earth rotates what is it called?
When the earth rotates, it is called orbit so we say the earth orbits around the sun.
Where are earthquake most likely to happen?
it accualy depends on what fault it is near and if your location is most vonerable to an a earthquake. in case you are wondering, a fault is a crevice in the earth where the earth is most likely to shake. lots of faults are really dangerous, so it is allways a safe idea to have an earthquake kit if you happen to live near a fault.
Core balance current transformer?
whats a core balance current transformer? Core Balance CTs are special CTs used to detect Earth faults & usually used for Restricted Earth Fault Protection. It is a ring type CT through which the cables carrying current of all the three phases (R,Y & B) are passed through. (In a 3phase 3 wire system) Under normal operating conditions, summation of current through the three phases shall be equal to zero. In event of a fault, the summation of the current shall no longer remain zero (zero sequence current shall flow during earth fault) & thus the fault can be detected.
