Interested to Buy Any Domain ? << Click Here >> for more details...
Answer Posted / satish
This type of protection provides a continuous check on faults within the points, where the C.T.s are used as in shown in fig 2. There are two sets of C.T.s; each set is mounted on either end of the stator phase. The secondaries of these current transformer sets are connected in star and their ends are connected together through pilot wires. The over current inverse time relay is connected across the equipotential points in the pilot wires, which will naturally be in center of these wires as shown in fig 2. But it’s convenient to locate these relays adjacent to the main circuit breaker; this can be achieved by inserting balancing resistance in series with the pilot wires to achieve equipotential point near the main circuit breaker as shown in fig 3. If there is no fault in the generator, same current will pass through the C.T.s at both the ends and there will be no current spilling into the relay.
Now if earth fault occurs as shown in fig 2, there will be an increase in current through set C.T.1 as compared to current through C.T.2. Thus there is no current balance any more resulting into spilling of current through the relay R hence tripping the circuit. If there is short circuit between the two phases as in fig3 it will also cause operation of relay R and tripping of the circuit breaker. This scheme does not provide protection for the turns of same phase
| Is This Answer Correct ? | 13 Yes | 3 No |
Post New Answer View All Answers
What are the commonly used schemes for the bus zone protection?
how to calculate the settings for shaft ct protn in hydro generators
How to measure current and voltage in an ELV circuit
Can 4pole (3 phase+neautral )RCCB proper functioning in only 3 phase load (no neautral, no Earth) ?
Does the direction of rotation of d.c. Shunt motor would get reversed if the armature current and field current both are reversed?
how does ELR works? explain
How can I calculate per unit (KWH) fuel (Gas/ Diesel both) consumption 1MW unit?
what are the applications of TIG welding
What is rotating magnetic field?Discuss elaborately.
why we have to particulary use ACB for below ratings,even available of MCB,MCCB with that range ?
in HT service 3ph 4 wire service Y-phase voltage shows zero . whether it is meter fault? or what be the reason ? if y-ph voltage zero ,can current is recorded? reasons for failure?
what are the condition that makes hooter blow?
i am trying to PSUs/govermeant jobs since last 2 years but still i m not success, plz help me.
typically in power distribution substation. 1- Any idea how would be the graph of capacitor bank consumption verses time through the day . 2- How is the switching ( on and off ) of the capacitor bank, per need?
What is the difference between PS & metering CT (5p20,0.5 etc.)? Why in PS class CT only Vk is given ? Is PS class CT is more accurate than metering CT?
