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Why metrosil is provided in differential protection?
under internal fault conditions , CT primary current produces steep insrease in voltage across the relay. This will exceed the burden 3kv normally designed as per. To get protected from the voltage, metrosil is connected across the relay , to drop the voltage.
Drop out voltage of a solid state relay?
Typically, when the coil voltage on a relay is decreased gradually, the relay "hold" will release at a certain voltage. This is usually defined as the Drop-out voltage (defined at some minimum value). Now, in the case of latching relay, the Drop-out voltage is called the Reset voltage.
Is feeder protection relay and ring main unit protection relay same?
No there not same
What is relay coil?
An electrical device, typically incorporating an electromagnet, which is activated by a current or signal in one circuit to open or close another circuit.Based on Characteristic the protection relay can be categorized as-Definite time relaysInverse time relays with definite minimum time(IDMT)Instantaneous relays.IDMT with inst.Stepped characteristic.Programmed switches.Voltage restraint over current relay.Based on of logic the protection relay can be categorized as-Differential.Unbalance.Neutral displacement.Directional.Restricted earth fault.Over fluxing.Distance schemes.Bus bar protection.Reverse power relays.Loss of excitation.Negative phase sequence relays etc.Based on actuating parameter the protection relay can be categorized as-Current relays.Voltage relays.Frequency relays.Power relays etc.Based on application the protection relay can be categorized as-Primary relay.Backup relay.Primary relay or primary protection relay is the first line of power system protection whereas backup relay is operated only when primary relay fails to be operated during fault. Hence backup relay is slower in action than primary relay. Any relay may fail to be operated due to any of the following reasons,The protective relay itself is defective.DC Trip voltage supply to the relay is unavailable.Trip lead from relay panel to circuit breaker is disconnected.Trip coil in the circuit breaker is disconnected or defective.Current or voltage signals from CT or PT respectively is unavailable.As because backup relay operates only when primary relay fails, backup protection relay should not have anything common with primary protection relay.Some examples of Mechanical Relay are-Thermal(a) OT trip (Oil Temperature Trip) (b) WT trip (Winding Temperature Trip) (C) Bearing temp trip etc.(a) Buchholz (b) OSR (c) PRV (d) Water level Controls etc.Float typePressure switches.Mechanical interlocks.Pole discrepancy relay.
What the three types of over current protection relay and describe the principles of operation?
over current protection relay
What is the number on the Reverse Voltage Protection Relay for a Ford Contour '97?
On a 1997 Ford Contour : The Reverse Voltage Protection relay location is marked ( D1 )
Where is the 1982 380sl fuel relay location?
behind the glove box.
How relay used for protection purpose?
Relay are operated by small current /voltage connected to Secondary side of Current Transformer and /or Voltage Transformer. The signal stimulates the magnetic substance nearby with the attracting force. This closes or opens the circuit being used in protection purpose.
What is the difference between voltage restrained overcurrent protection and voltage controlled overcurrent protection?
Voltage restrained overcurrent protection uses a fixed voltage threshold to trip the protection device when an overcurrent condition is detected. In contrast, voltage controlled overcurrent protection adjusts the trip threshold based on the system voltage level, allowing for more precise coordination with other protective devices and better protection of the equipment. The key distinction lies in the method of setting the trip threshold: fixed voltage for voltage restrained, and voltage-dependent for voltage controlled overcurrent protection.
What is directional protection relay and how is it works?
Directionalized relays are relays that use a polarizing circuit to determine which "direction" (in the zone of protection, or out of the zone protection) a fault is. There are many different types and different polarizing methods - ground polarizing, voltage polarizing, zero sequence voltage polarizing, negative sequence polarizing, etc. The basic operation of this relay is just like any nondirectional relay, but with an added torque control - the directionalizing element. This element allows the relay to operate when it is satisfied that the fault is within the zone of protection (ie not behind where the relay is looking).
Where you use undervoltage protection?
Undervoltage protection is provided for A circuit bars,motors, generators, transformers, rectifiers, etc.. Such protection is given by means of undervoltage relay. Undervoltage relay are necessary for voltage control and reactive power control of network buses and load buses. These type of relays have inverse time characteristics and their operating time reduces twith the reduction in operating voltage. Undervoltage protection is provided for AC circuit bars,motors, generators, transformers, rectifiers, etc.. Such protection is given by means of undervoltage relay. Undervoltage relay are necessary for voltage control and reactive power control of network buses and load buses. These type of relays have inverse time characteristics and their operating time reduces twith the reduction in operating voltage.
What is distance really?
The most common form of protection on high voltage transmission systems is distance relay protection. Power lines have set impedance per kilometre and using this value and comparing voltage and current the distance to a fault can be determined. The ANSI standard device number for a distance relay is 21
Why metrosil is provided in differential protection?
under internal fault conditions , CT primary current produces steep insrease in voltage across the relay. This will exceed the burden 3kv normally designed as per. To get protected from the voltage, metrosil is connected across the relay , to drop the voltage.
Where is the relay switch for the head lights located on a 1992 Pontiac Firebird?
There is no relay. The voltage comes from the fuse box directly to the headlight switch.
What is the purpose of voltage transformer?
A 'voltage transformer' (called a 'potential transformer' in North America) is classified as an 'instrument transformer', and is used to reduce the voltage of an electrical system to a lower, safe, level for the purposes of either operating a voltmeter or supplying a protection relay. At the same time, it electrically-isolates the meter or relay from the high-voltage system.
Wire to electric fuel pump has low voltage?
if you have checked the voltage with a dvom then you need to verify that the power source at the fuel pump relay is correct, if it has the correct voltage pre-relay then your problem is post-relay. if the voltage is not correct pre-relay then simply trace and repair the power source. if the problem is post relay then check the output voltage directly at the relay, if voltage is good trace and repair line from relay to pump. if voltage is not correct then replace the fuel pump relay
Drop out voltage of a solid state relay?
Typically, when the coil voltage on a relay is decreased gradually, the relay "hold" will release at a certain voltage. This is usually defined as the Drop-out voltage (defined at some minimum value). Now, in the case of latching relay, the Drop-out voltage is called the Reset voltage.
