Why use the VCB at High Transmission System? Why can't use ACB?

1 Answer

Answer :

Actually the thing is vacuum has high arc quenching property compare to air because in VCB, the die electric strengths equal to 8 times of air. That y always vacuum used as in HT breaker and air used as in LT.

Related questions

Description : What do ABCB and ACB mean? 

Last Answer : ABCB – Air blast circuit breaker. ACB – Air circuit breaker. 

Description : On a common hypotenuse AB, two right angled triangles, ACB and ADB are situated on opposite sides. -Maths 9th

Last Answer : According to question ∠BAC = ∠BDC.

Description : On a common hypotenuse AB, two right angled triangles, ACB and ADB are situated on opposite sides. -Maths 9th

Last Answer : According to question ∠BAC = ∠BDC.

Description : triangle ABC is right angled at A. AL is drawn perpendicular to BC. Prove that /_ BAL = /_ ACB -Maths 9th

Last Answer : NEED ANSWER

Description : triangle ABC is right angled at A. AL is drawn perpendicular to BC. Prove that /_ BAL = /_ ACB -Maths 9th

Last Answer : This answer was deleted by our moderators...

Description : In the figure (not to scale ), O is the centre of the circle and `/_OBA=30^(@)`. Find `/_ ACB`

Last Answer : In the figure (not to scale ), O is the centre of the circle and `/_OBA=30^(@)`. Find `/_ ACB`

Description : In the above figure, O is the centre of the circle AB,AD and CD are the chords . If `/_ ADC=130^(@)` then fid `/_ ACB`.

Last Answer : In the above figure, O is the centre of the circle AB,AD and CD are the chords . If `/_ ADC=130^(@)` then fid `/_ ACB`.

Description : In the following figure, if `/_ AOB =60^(@)` then `/_ ACB=30^(@)`. [True `//` False `//` Cannot say ]

Last Answer : In the following figure, if `/_ AOB =60^(@)` then `/_ ACB=30^(@)`. [True `//` False `//` Cannot say ]

Description : In a uniform ring of resistance `R` there are two points `A` and `B` such that `/_ ACB = theta`, where `C` is the centre of the ring. The equivalent r

Last Answer : In a uniform ring of resistance `R` there are two points `A` and `B` such that `/_ ACB = theta`, where `C` ... ))` D. `(R )/(4pi^(2))(2pi-theta)theta`

Description : String Processing --- Write out a function that prints out all the permutations of a string. For example, abc would give you abc, acb, bac, bca, cab, cba.

Last Answer : void PrintPermu (char *sBegin, char* sRest) { int iLoop; char cTmp; char cFLetter[1]; char *sNewBegin; char *sCur; int iLen; static int iCount; iLen = strlen(sRest); if (iLen == 2) { iCount++; ... printf("\nEnter a string:"); scanf("%s%*c",sIn); memset(s,0,255); PrintPermu(s, sIn); }

Description : What is the meaning of ACB, MCCB, NFB?

Last Answer : Air circuit breaker for 400V higher current ratings. Moulded case circuit breaker for 400V medium current ratings. No Fuse Breaker – 75 A capacity

Description : If you press the ACB Close button on an idle generator what will happen?

Last Answer : Ask E/O. Normally, the breaker won’t close until you synchronise, so even if you press the breaker close, it will not close. The breaker has under-voltage protection which will not let you close it.

Description : What is the full form of ACB?

Last Answer : Air circuit breaker. It is normally used at 400V and higher current applications (generator breakers).

Description : Why we use Vacuum Circuit Breaker in High Transmission System and not Air Circuit Breaker?

Last Answer : A:Vacuum has high arc quenching property compare to air . The dielectric strength of vacuum is equal to 8 times than air . Hence vacuum circuit breaker is used in High voltage line and air circuit breaker is used in low voltage lines.

Description : In order to reduce the harmful effects of harmonics on the A.C. side of a high voltage D.C. transmission system ______are provided. (A) synchronous condensers (B) shunt capacitors (C) shunt filters (D) static compensators

Last Answer : Ans: C Xc= 1/ ωc

Description : What are the advantages of high voltage transmission?

Last Answer : a. Saving in conductor materials. b. Low power loss (I2 R) of transmission lines due to decrease in current. c. Better efficiency of line due to fewer losses. d. Better voltage ... section of conductor distance between the poles increases and the cost decreases and the labour cost also decreases.

Description : Transmission efficiency of transmission line increases with the: a) Decrease in power factor and voltage b) Increases in power factor and voltage c) Increase in power factor and decrease in voltage d) Increase in the voltage but decrease in the power factor

Last Answer : Ans: B

Description : When a transmission line has a load impedance same as that of the characteristic impedance, the line is said to be a) Parallel b) Perpendicular c) Polarized d) Matched

Last Answer : Ans: D

Description : The leakage current in the transmission lines is referred to as the a) Resistance b) Radiation c) Conductance d) Polarisation

Last Answer : Ans: C

Description : When the current flow in a power transmission line is halved, the power loss _____________. A. is halved B. is doubled C. is divided by four D. remains the same

Last Answer : Answer: C

Description : When the current in a power transmission line is increased, the power loss _____________. A. increases as the square of the current B. decreases as the square root of the current C. remains the same, as it is independent of current flow D. increases in direct proportion as the current

Last Answer : Answer: A

Description : When the current flow through a power transmission line is doubled, the power loss _____________. A. is halved B. is doubled C. is quadrupled D. remains the same

Last Answer : Answer: C

Description : While starting a main propulsion synchronous motor, the ammeter pegs out at maximum and then returns to the proper value after synchronization. This indicates the _____________. A. motor has started ... field windings are grounded C. slip rings are dirty D. power transmission cables are grounded

Last Answer : Answer: A

Description : What are the different relays that employed for protection of apparatus and transmission lines?

Last Answer : Answer: The relays that are usually employed for protection of transmission lines include • Over current relay • Directional relay • Distance relay • Under Voltage relay • Under-frequency relay • Thermal relay • Differential relay • Phase sequence relays • pilot relays

Description : Why Earth Wire is provided in the overhead transmission lines?

Last Answer : Earth wire is provided above the overhead transmission lines for protection against lightning strokes. The ground wire or earth wire protects the phase conductors or line conductors by attracting itself the ... traveling waves set in the lines by acting a short circuit secondary of the line current

Description : What is the first equipment of the substation connected to the incoming transmission line?

Last Answer : Lightning arrestor is the first equipment of the substation connecting the incoming transmission lines. It protects other substation equipment from lightning and switching surges by suppressing them to ... between both the ends of major equipment such as power transformers for protection.

Description : Why, when birds sit on transmission lines or current wires doesn't get shock?

Last Answer : It's true that if birds touch the single one line (phase or neutral) they don't get electrical shock... if birds touch 2 lines than the circuit is closed and they get electrical shock. so ... is grounded..So that means that human who touch the line closes the circuit between phase and neutral.

Description : Why transmission line 11Kv OR 33KV, 66Kv not in 10kv 20kv?

Last Answer : Due to the form factor=1.11, so output voltage must be multiply of form factor, so we get 11, 22, 33 the answers mentioning the form factor 1.1 are correct. Just one clarification... 1.1 is ... available with terminal voltages from 10.5 kV to 15.5 kV so generation in multiples of 11 does not arise.

Description : What is the basis of selection of electrical transmission voltage?

Last Answer : 1. Material of transmission line. 2. Rating of wire. 3. Environments 4. Load to be driven and many more things

Description : Why, when birds sit on transmission lines or current wires doesn't get shock?

Last Answer : A:Its true that if birds touch the single one line (phase or neutral) they don't get electrical shock... if birds touch 2 lines than the circuit is closed and they get electrical shock.. so if a human ... the air. If he is standing on the ground then touching the line (phase) he will get a shock.

Description : Mention any two disadvantage of carrier current scheme for transmission line only.

Last Answer : The program time (ie, the time taken by the carrier to reach the other end-upto .1% mile); the response time of band pass filter; capacitance phase-shift of the transmission line .

Description : What is long transmission line?

Last Answer : Length is more than 150 km Voltage level is above 100 kV Line constants are considered as distributed over the length of the line.

Description : What is Medium transmission line?

Last Answer : Length is about 50km to 150km Operational voltage level is from 20 kV to 100 kV Capacitance effect is present Distributed capacitance form is used for calculation purpose.

Description : What is short transmission line?

Last Answer : Length is about 50 km. Voltage level is up to 20 kV Capacitance effect is negligible Only resistance and inductance are taken in calculation.

Description : What are the types of transmission line?

Last Answer : Short Transmission Line Medium Transmission Line long Transmission Line

Description : What is transmission line?

Last Answer : Transmission line is the long conductor with special design (bundled) to carry bulk amount of generated power at very high voltage from one station to another as per variation of the voltage level.

Description : Why humming sound occurred in HT transmission line?

Last Answer :  This sound is coming due to ionization (breakdown of air into charged particles) of air around transmission conductor. This effect is called as Corona effect, and it is considered as power loss.

Description : What are the various kind of cables used for transmission?

Last Answer : Cables, which are used for transmitting power, can be categorized in three forms: • Low-tension cables, which can transmit voltage upto 1000 volts. • High-tension cables can transmit voltage upto 23000 volts. • Super tension cables can transmit voltage 66 kV to 132 kV.

Description : If sending end voltage is Vs at no-load in a transmission line then receiving end voltage is if ABCD parameters of line is given a) Vs b) Vs/A c) 0 d) Infinity

Last Answer : Ans: Vs/A

Description : The regulation of Short Transmission lines depends up on a) Distance of line b) Frequency c) Power factor d) All

Last Answer : Ans: Power factor

Description : ACSR (Aluminium Conductor Steel Reinforced) are used as (A) over head transmission lines. (B) super conductors. (C) fuse (D) underground cables.

Last Answer : (A) over head transmission lines.

Description : The voltage at the two ends of a transmission line are 132 KV and its reactance is 40 ohm. The Capacity of the line is (A) 435.6 MW (B) 217.8 MW (C) 251.5 MW (D) 500 MW

Last Answer : (A) 435.6 MW

Description : The size of the feeder is determined primarily by (A) the current it is required to carry. (B) the percent variation of voltage in the feeder. (C) the voltage across the feeder. (D) the distance of transmission.

Last Answer : Ans: A Size of conductor depends upon amount of current flow.

Description : As the voltage of transmission increases, the volume of conductor (A) increases. (B) does not change. (C) decreases. (D) increases proportionately.

Last Answer : Ans: C Decreases due to skin effect.