Question { EEE, 47744 }

What is meant by Reactor in power system and what are the
uses?

Answer

Reactors are mainly used to limit,the flowing of very large short circuit current during fault. it main function is to protect the plant, by limiting the amount of power that can flow into the faultier part by all other parts of the system.Eg.,Generator reactors,feeder reactors,busbar reactors,etc.

Question { Areva, 10884 }

why current transformer secondary side should be shorted ?

Answer

yes above answers in context of not being open circuited are true.
But If the secondary impedence is not kept as low as possible(as during short circuit ), then there is a voltage drop across it , which result in a decrease in CTs accuracy.

Question { Honeywell, 2792 }

How is The split core current transformer working ?

Answer

I think its working is same as ordinary low rating CTs of same class.......because in split core CT we only split or open or break the core so that as per our requirement the no. of primary windings or copper plate can enter inside into the core.

Question { 4351 }

what is means of ALF,kPV(min),lexc(max)at Vk,Rct@75 degree
centrigate ohm in current transformer name plate?

Answer

ALF--accuracy limit factor(ratio of nominal over current to the rated current)
KPV--knee point voltage(secondary voltage must be less than KVP so that ct accuracy will not hampered)
KPV=k.Is(Rct+Zs) where Rct=resistance of secondary winding at 75 c

Question { Cipla, 6008 }

when we connect the capacitor banks in series with the
circuit?

Answer

For a filter type operations the capacitor banks are connected in series with the circuit.
It is used to eliminate undesired frequency components resulting from thyristor controlled circuits.It is also used in order to separate out carrier frequency signal from the audio frequency in AM detection.

Question { Bhel, 7933 }

what is diff b/w electrical & electronics ?

Answer

When current flow due to movement of electrons only then it
is called electrical.Ex- conductors

and when the flow of current is due to the movement of
electrons as well as from holes then it is called
electronics.
Ex-semmi-conductor

Question { Orchid, 11539 }

What is the difference between lubricating oil and insulating
Oil?

Answer

lubricating oil is used in order to reduce friction from
moving parts, to make somthing run smoothly without any
problem.
But,insulating oil is used to insulate parts at different
electrical potential i.e., to protect or isolate some
meterials from the passage of electricity.

Regarding the viscosity of the insulating fluids it is
highly desirable that they have a low viscosity (as long
they keep inflamability at a reasonable level) as this
helps the removal of heat out of the transformer.
Hope this is of help.

Question { Bhel, 5886 }

why can't we increase the voltage by increasing the field
voltage in order to get higher voltage.so that we can
eliminate step up transformer

Answer

i think that, if we increase the field voltage from certain
limit then there will be a chance of sarturation in the
machines.

Question { Power Grid, 3190 }

Is it really necessary to have reactive power in transmission line to transfer the power from one place to other?

Answer

there are two main reason for the need of reactive power.:
(1)Reactive power is needed to control the voltage level in transmission line.so If the voltage drops or become zero(because of no reactive power), the current must be increases in order to maintain the same power.If the current is too much then their is a failure of insulation for which the transmission lines go off line.
(2) IF there is less or no reactive power in the line then the generators, motors, transformers connected with the line will not work ,because they need reactive power for magnetization,hence the power will not transmitted.
Nowadays,there is a HVDC transmission which does not require reactive power to transmit,but it is needed in converters,solid states devices,semiconductors ,inverters..

Question { 1545 }

For 35 HP motor how much amount of capacitor should be on in kvr to reduce the current bill

Answer

it will depend on load hence the p.f of of the motor.If the load will vary we use automatic type pf controller.
If the pf of motor is not known...there is a jugaad rule of thumb that (kvar<=33.3%of motor HP).In this case capacitor should be less than 11.55 kvar