Interested to Buy Any Domain ? << Click Here >> for more details...
Why restricted earth fault protection is needed? Why can’t
differential
Protection is sufficient?
- 3 Answers
- 18994 Views
- I also Faced
- E-Mail Answers
Answer Posted / bandarawy
Due to the fact that current transformers always have a
certain error, the differential current always differs from
zero as soon as there is a load current flowing. Especially
during a through-fault condition with high short circuit
current , the differential current may be very high due to
the error of the current transformers. Depending on the
sensitivity of the setting value of the overcurrent
protection relay, when it is used as a simple differential
protection relay, unwanted tripping may occur.
For this reason, it is necessary to stabilize the
differential protection by means of a so called bias
current. For the restricted earth-fault protection using
the biased differential protection principle
| Is This Answer Correct ? | 3 Yes | 8 No |
Post New Answer View All Answers
explain comutator action in detail.thanks
What is current divider rule (cdr)?
The size and construction of bushings in a transformer depend upon?
why we take movement of rotor always in counter-clockwise direction in 3-phase induction motors?
How relay works, reverse relay, master relay, os relay, earth fault relay and what is its setting point
Is it true that in the 3 phase transformer, the limbs of the core are at 45 dgrees to each other. if true, why?
What do you mean by cogeneration? What its working principle?
Define norton equivalent circuit?
What are the two types of compensation?
What is the Minimum winding resistance of motors ( small & big)? referance range
Graphs of measuring power and speed on dc motor
how to calculate sizing of NGTR (Transformer rating,Loading resistor value and Current rating of resistor) and what is the X/R ratio. Details : 11kV,Capacitance 1.73532 micro farads,40kA for 1sec.
what is the use of static frequency converter and static excitation equipment? and where it is employed? for what?
we are going to install a solar PV site and how can we calculate PV Solar Panel Efficiency, can anybody tell me complete method for its calculation.
we have one oven for 12 zone we are installed ir lamp in oven we control load from thyrister and 0 to 5vdc so our zone no 8 getting bright in fraction of second so what we do.. Please answer
