Interested to Buy Any Domain ? << Click Here >> for more details...
This is about the recent problem that we have faced in our
project site.
We have 6/7.5 MVA. 66/11kV three phase star - star power
transformer. The neutral was solidly connected to the
earthing mat. But because of high resistance of earthing
mat (130 ohm on LV and 180 ohm on HV), one day LV side
neutral earthing conductor melted and we had a huge damage.
Can any one plz tell me what might happen when we connect
power transformer neutral to the earthing mat which has
high resistance (>100 ohm ) ?????
- 2 Answers
- 4552 Views
- I also Faced
- E-Mail Answers
Answer Posted / gairhe
I think you are right.
for the LV even if the imbalance neutral current is 10 A,
the 130 ohm resistance will produce GPR ( Ground Potential
Rise ) of 10 X 130 = 1.3 kV.
Also at the site the transformer neutral earth conductor was
touching the 185 sq mm single core copper power cable and
control cable. May be because of this high GPR , sparking
occurred and heat was generated.
The neutral earthing conductor is of size 95 sq mm. so 10 A
current is not a big issue.
In my view 1.3 kV and sparking developed heating at the
group of XLPE power cable, control cable and fire started .
Then the XLPE power cable was damaged and because of the hig
earth fault from the damage of XLPE cable, the near by
neutral earthing conductor got melted.
| Is This Answer Correct ? | 1 Yes | 0 No |
Post New Answer View All Answers
what is the affect of earth's magnetic field on the frequency used in aircraft???
pls tell what are doing the three phase motor star and delta connetion with circuit diagram and control wiring .
What is a single phase autotransformer?
is all the servo motors having brake?please specify which servo motors having brake for stop on position and which are not.
BRIEFLY EXPLAIN THE STORAGE CLASSES AND THEIR TYPES IN C
Difference between transition and diffusion capacitance
What is s-domain and its significance?
What is the role of feedback in a closed loop control system?
why is the power generator connected as star earthed or star earthed through reactance and what its features ?
What is the working principle of MIG welding? and its out put Voltage?
how we can calculate chiller required ampear?
hi friends ,iam working as genset AVR service engineer in electrical field from past 2 yrs throughout india . i plan to shift in some other job without travelling in same field because i con't travel,i dont know what i do for that so please guide me what job is suited for me,how i can serch the job please anybody helpme iam totally confused
what ispositive, negative, zero sequence impedence?
how to test power transformer.YNd11
How to convert 2 phase to 3 phase electricpower in induction moter?
