How can we calculate the fault level of the distribution
system knowing the percentage impedance of transformer &
subsequent equipments.
Answer Posted / pankaj
THERE IS A SIMPLE CALCULATION IF ASSUMING INFINITE SOURCE
BUS THE MAX LEVEL OF FAULT AT LT SIDE OF A 11/0.433 5%
1000KVA TRANSFORMER CAN BE CALCULATED AS:
KVA*100/SQRT3*433*Z% kAMPS
1000*100/1.732*433*5 = 26.7kAMS
| Is This Answer Correct ? | 39 Yes | 7 No |
Post New Answer View All Answers
what is plunger and what's the use of it in motor alignment?
A 230V dc shunt wound motor has an armature resistance of 0,15Ω.When operating on no load at 650 rev/min the armature current is 6A . The motor takes a full load current of 85A. Calculate the full load speed if the field flux is (i) maintained constant (ii)reduced by 0,03
why cable i burning without tripping. how can protect led street lights
When we use air circuit breaker, it has O/L protection ,time delay SC protection, Instataneous SC protection & ground fault protection. They all have some setting range. But what is the suitable/allowable setting for the above protection which will be safe for the equipment? For example-O/L protection setting have a range of (0.4,0.45,0.5,0.55,0.6,0.65,0.7,0.8,0.9,1.0)xIn Time delay SC protection have a range of (1.25,1.5,2,3,4,6,8,10,12)xIn Time delay setting is 0.02,0.1,0.2,0.3,0.4 Instataneous setting is fixed to 20xIn Gound fault setting is given 100A,300A,600A,900A,1200A This setting are for 2500A ACB. So what will be the basic allowable setting for the above protection? is there any formulae to calculate this<
why using transformer and thyristor switch in 3 phase apfc panel
Ratings of power transformer,Distribution transformer.
What is the general system requirement of alternator?
what is the star delta connetion and how can do it a three phase motor with control witing with picture
What is d main advantage of using double circuit 3 phase transmission ?
A 500 V shunt motor runs at its normal speed of 250rpm when the armature current is 200A. The resistance of the armature is 0.12 Ω. Calculate the speed when a resistance is inserted in the field reducing the shunt field to 80% of normal value and the armature current is 100A.
Some times to change of DOR of a motor, interchange of R & B is not effected and RYB take same current, but interchange of R&Y is effected ie change the DOR. My doubt is what is the problem in motor and how it is happen.
how indusrial diesel generator work
The knee point of a current transformer is normally unique and known.So why in the nameplate of a CT they put the minimum value like this Vk> 400v.
What are the two types of compensation?
What is the difference between the relay and the circuit breaker?