The average rate of rise of re-striking voltage upto first peak is. A 50 Hz, 11 kV, 3-phase alternator with earthed neutral has reactance of 7 ohms per phase and is connected to bus-bar through a circuit breaker.
What is the average rate of rise of restriking voltage upto the first pic?
| Q. | What is the average rate of rise of restriking voltage upto the first peak? |
|---|---|
| B. | 453 * 103kV / sec |
| C. | 582 * 103 kV / sec |
| D. | 467 * 103 kV / sec |
| Answer» b. 453 * 103kV / sec |
Similarly, On what factor does the rate of rise of restriking voltage RRRV depend? So, the rate of rise of re-striking voltage (RRRV) is dependent upon both the inductance and capacitance of the system.
What is average RRRV in circuit breaker?
and the RRRV is below 1.54kV/µs. Current Chinese and IEC EHV/UHV CB standard, requires CB’s to withstand a TRV peak value of 2.5 p.u. and RRRV of 1.54 kV/µs when interrupting 25 % of rated breaking current.
What is its average RRRV Mcq?
What is its average RRRV? A 50 Hz, 11 kV, 3 phase alternator with earthed neutral having a reactance of 3 ohms per phase and is connected to a bus bar through a circuit breaker, if the distributed capacitance upto CB between the phase and neutral is 0.01 μ F. Q5.
On what factor does the rate of rise of restriking voltage RRRV depends?
So, the rate of rise of re-striking voltage (RRRV) is dependent upon both the inductance and capacitance of the system.
What is full form RRRV? RRRV. Rate of Rise of Recovery Voltage.
What is the full name of RRRV for circuit breaker? Voltage that appears between the contacts of the circuit breaker after arc extinction during opening process while clearing a fault. The Rate of Rise of Recovery Voltage (RRRV) is defined as peak transient recovery voltage divided by the total time from zero voltage to peak voltage.
What happens in the arc extinction using high resistance method?
Arc resistance is increased with time. No change it remains same. Arc resistance is kept zero.
What happens in the arc extinction using high resistance method Mcq? What happens in the arc extinction using high resistance method? a. Arc resistance is decreased with time.
What is the interrupting medium in the contactor *?
Air at atmospheric pressure.
How do I reduce RRRV? Apply surge capacitors at terminal of circuit breaker to reduce RRRV.
What is RRRV What is its unit?
It is the rate of increase of restriking voltage and is abbreviated by R.R.R.V. its unit is kV/m sec. Consider the fig2 below showing the opening of circuit breaker under fault conditions.
What is the actuating quantity for the relays Mcq?
| Q. | What is the actuating quantity for the relays? |
|---|---|
| B. | Frequency |
| C. | Phase angle |
| D. | All of these |
| Answer» d. All of these |
What are fault diverters? Fault diverters, or crowbars, have proven to be very effective protection against transient-induced power arcs within accelerator oscillator tubes. This device short circuits the oscillator-plate power supply in the event of an over-current, thus removing the power flow from the fault within a few microseconds.
What is the interrupting medium in the contactor?
Air at atmospheric pressure.
What measures are taken to reduce Restriking voltage and RRRV?
To reduce the restriking voltage, RRRV and severity of the transient oscillations, a resistance is connected across the contacts of the circuit breaker. This is known as resistance switching.
How does Restriking voltage affect arc interruption process in circuit breakers? Voltage Race Theory
If we remove ions at the initial stage either by recombining them into neutral molecules or inserting insulation at a rate faster than the rate of ionization, the arc can be interrupted. The ionization at zero current depends on the voltages known as restriking voltage.
How do you find the voltage across a breaker contact?
We are now required to find the voltage across the breaker contacts immediately after the breaker contact opening. where ω0 = 1 / √LC and hence f0 = (1/2π√LC) where f0 is the natural frequency of oscillation. Expression (3) is the restriking or transient recovery voltage.
In what factors does the arc resistance depends? The arc resistance depends upon the following factors: (i) Degree of ionisation – the arc resistance increases with the decrease in the number of ionised particles between the contacts. (ii) Length of the arc – the arc resistance increases with the length of the arc i.e., separation of contacts.
Which voltage appears across the contacts of the circuit breaker after final arc extinction?
Recovery voltage: It is the normal frequency (50 Hz) RMS voltage that appears across the contacts of the circuit breaker after the final arc extinction. It is approximately equal to the system voltage.
What happens when a fault occurs in a high voltage transmission line? Circuit breaker operates then the relay. Relay operates and then the circuit breaker. Relay operates, then successively the isolator and the circuit breaker.