why should we place 9KV lightning arrestors in 11KV
substation ?
Answer Posted / d. bhowmick
All power system devices are designed with certain
tolarence limits.This is because it is always desirable
that the equipments/devices can withstand transient
voltage/current rise without any damage up to a certain
preset limit.
For an 11 KV line, the effective phase to ground voltage is
6.35 KV. That is, an LA associated with this line(between
the phases & ground)is supposed to operate when the system
voltage exceeds 6.35 KV. However, in many cases the system
voltage may momentarily rise above this value owing to
switching action or induction-that can easily be tolarated
by the associated equipments(having their individual
tolarances). Under this circumstance, it is desirable that
the LA donot unnecessarily operate especially when the rise
in voltage is within the tolance limit of the associated
equipments. To enable this, LAs with slightly higher value
of voltage rating are provided for a system operating at a
certain system voltage. Clearly, for a 6.35 KV(L-G)system
associated with a 9 KV LA, no damage is expected to be
caused if the system voltage rises by a maximum of 2.65 KV.
Beyond this, the LAs will come into action.
| Is This Answer Correct ? | 46 Yes | 1 No |
Post New Answer View All Answers
while doing high potential for 11KV 3 core cable how much leakage current will obtain?, what will be acceptance value?
Which material is used for the core of a transformer and why?
what is the size of ht cable of 33kv ht line and transformers ratings are 1 Mva and 5mva.please send formula also.
in an electronic tri vector meter when the current and voltage sequence changes ? what is the effect of phase sequence on recording of meter
i need of the bhel question papers along with answers and also give some website names for the downloading question (electrical and electronics engg question)please help me....
Make a list observation on Transformer?
which protection function should measure RMS value of current&DFT value of current?
slipring induction motor starting time Lrs operating why lrs starting time lrs outer body didn't get shock
Give details on how you intend to handle a challenging position you are posted to manage unexpectedly as a company staff?
In Electrical 'Single Line Diagram' cable nomenclature shows "2 X 1C X 630sq.mm to be provided for one incomer. The question is how many cable to be proved for one Incomer.
do we use links in a dc circuit?if so what s its use in it?
How to connect the chemical earthing and complete process tell me plz
What are the parts in a inverter?
if flux and load static in dc motor and supply voltage increases 20% then what happened in speed
current transformer balance the power level on both sides. e.g in case of step up, at secondary side voltage rise but current decrease and vice versa in case of step down transformer. but how this power level remains same in case of current transformer and voltage transformer