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negative phase relay is used for the protection against unbalanced condition
in a basic model a wheastones bridge is used with the operating coil connected across it.when any fault occurs unbalance will occur in the system and the relay will operate
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∙ 13y ago
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How Negative phase sequence relay work?
How Negative phase sequence relay work
How is Negative phase sequence relay operated?
please see details in this site http://electricalandelectronics.org/2009/03/17/negative-phase-sequence-relay/
What is the Mechanism of negative phase sequence relay?
A negative sequence relay is looking at unbalanced current, such as what would result from a line to line or line to ground fault. I'm not sure what you're meaning by "mechanism". Please explain if the above doesn't answer your question.
What is phase failure relay?
These relay sense the Negative Sequence Voltage components of system supply & offers protection against Phase Failure, Phase Sequence Reversal with Under/Over Voltage conditions which are dangerous to motor winding and cause motor burnouts.
What will happen if negative sequence relay is absent in generator?
The flux capacitor will overload and you will fail to reach 88 mph.
What is a phase overload relay?
only the single phase monitored at which it installed
How is a IDMT relay used to give protection against a phase to earth fault a phase to phase fault on a feeder?
As with any IDMT relay the higher the fault current the quicker the trip time.
3 phase reverse relay can be utilized for motor control speed?
3 phase reverse relay can be utilized to control 480V motor 60HZ for controlling their speedspeed.
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).
What is mean by Zero phase Current transformer?
at first what is zero sequence current.. Zero sequence currents, in simple terms, are those found in the neutral conductor. They include the unbalanced 50 Hz currents and the 3rd, 9th, 15th and other triplen harmonic currents. Zero sequence currents appear in the neutral because they do not cancel in the way that 50Hz currents cancel. This is due to the fact that the zero sequence component on one phase is always in phase with the zero sequence components of the other 2 phases. we can say 50 Hz current on one phase, on the other hand, is always 120° out of phase with the other phases 50 Hz current which causes their balanced portions to cancel in the neutral. now, any method of ground current sensing involves detecting zero sequence currents. For solidly grounded systems, connecting the phase current transformers together with a common return allows measurement of zero sequence current in the common lead, if there is no neutral load current. The vector sum of the phase currents is equal to the zero sequence ground current. Under normal load conditions, the vector sum of the three phase currents is near zero. It is not exactly zero as the system capacitive charging current of the load circuit is non-zero. but it is limited value..if it is beyond the limit this zero sequence CT take care of it. All phase conductors are passed through the window of a single CT referred to as a zero sequence CT. Under normal circumstances, the three phase currents will sum to zero resulting in an output of zero from the zero sequence CT's secondary. If one of the phases were shorted to ground, the sum of the phase currents would no longer equal zero causing a current to flow in the secondary of the zero sequence CT. This current would be detected by the relay as a ground fault. Regards, Balaji K APL, Ahmedabad
Can you replace an 3 phase solid state relay with a contactor on a 3 phase heater?
Not without other modifications. The circuits used to turn the solid state relay on will not be suitable for turning a contactor on.
What is the working principle of phase failure relay?
A phase failure relay monitors the incoming three phase service lines. If the lines become reversed or loss of one phase causing single phasing, the relay's internal contacts change status. In control panels the control voltage usually is connected through the phase failure relay's auxiliary contacts. If any line anomalies occur the control voltage is cut off and the panel becomes inoperable. Once the line fault is corrected the fault relay senses that everything is alright and then allows the control voltage to power the control panel again.
