As with any IDMT relay the higher the fault current the quicker the trip time.
MCB stands for miniature circuit breaker , which provides protection against over current. the setting is not adjustable. RCB stands for residual circuit breaker which provides protection against earth fault as well as over current. It monitors the current difference between phase and neutral and if the difference is more than rated value say 200 milli amps it will trip.
A break in the Earth's surface might be called a chasm, a fissure, or a fault line.
There is really no "average" fault because all of the fault lines on the earth join together. There are names for different sections of the fault lines, most notably the one in the Pacific Ocean called the mid-Pacific oceanic ridge.
There are 3 main types of faults 1. Normal 2. Strike slip 3. Reverse(Thrust) In a normal fault the foot wall stays in place while the hanging wall moves DOWNWARDS In a strike slip the tectonic plate(s) slide past each other horizontally In a reverse fault, the hanging wall gets pushed UPWARDS over the foot wall (The pictures are in the reverse order)
Fault creep is slow movement along a fault line with NO resulting earthquake.
Restricted earth fault protection is used to protect a specific zone, and should not trip for a fault outside of that zone (usually limited to a transformer, and possibly extending to lowside, highside, and tertiary breakers). Stand by earth fault protection is a term I am not very familiar with, but I believe this would be protection that is meant for a specific zone as backup, and can operate for faults outside of this zone. An example might be a highside time overcurrent relay set looking into a transformer, where the transformer is protected by a differential (primary protection), and there is a lowside feeder with relays (primary protection). The highside overcurrent acts as a backup (secondary protection) for the transformer and the feeder, and is delayed due to the nature of a time overcurrent relay.
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.
Restricted earth fault protection is used to protect a specific zone, and should not trip for a fault outside of that zone (usually limited to a transformer, and possibly extending to lowside, highside, and tertiary breakers).
If the fault is a direct short to ground, the fault current can be high enough to trip the upstream protection.
Fuses do not provide protection against ground faults. Protection against a ground fault can be provided by breakers. If a fuse blows, it has to be replaced. If a breaker is tripped to off due to a surge in electrical current, the breaker can be reset.
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.
I'm guessing this is in reference to a restricted earth fault, and you want to know what the opposite is? Restricted earth fault protection is designed to operate for earth faults within a specific zone. Unrestricted protection will operate for faults "anywhere", as long as the pickup can be satisfied. For example, REF (restricted earth fault) transformer protection looks for a small amount of neutral current, and if this exists, and the relay identifies this current as being within the zone of protection, the relay will trip. If it were unrestricted, the small amount of neutral current alone would be enough to cause a trip.
10mA
The ground earth wire serves two purposes: To trip the protection as quickly as possible if theres an out of balanced current or a fault to earth. and to bring the user to the same potential to the earth if there is a fault and the protection doesnt trip. that way because you are at the same potential as earth you will not get electrocuted.
Requirement of REF protection for 50KVA 11KV/.4KV transforemr
An isolation transformer is a mutual transformer having a voltage ratio of 1:1, so that the secondary circuit is electrically isolated from the primary circuit, yet subject to the same voltage.An earth protection relay is a category of protective relay that responds to an earth fault monitored by a current transformer (CT). In the event of an earth fault being detected by the CT, the relay with activate the trip circuit to a circuit breaker which will then disconnect the fault.
To prevent overheating/damage/fire of the electrical components in a circuit.