I have connected 04nos. earthings to a transformer through
04nos. earthing pits seperately. 02nos. earthings are
connected to T/F body, and 02nos. earthings are connected to
T/F neutral.T/F capacity is 2000KVA, 11KV/415V. But after
completing of 02 years successful operation ,we are
facing following problems-

1. CT/PT occured blast one time
2. HT cable box occured blast two times
3. One body earthing strip and one neutral earthing strip of
transformer are overlapping at some places. Whenever these
two strips are pressed at overlapped points, they made spark.

What is the reason of spark?

Please explain the reason & rectification of above problems

Answer Posted / siva kumar

because of improper earthing the transformer neutral voltage may raise to abnormal level and may cause failure of CT/PT sets.
The star point you made on secondaries of CT, should be made at the equipement only and connected to earth to avoid transfer potential.
If you have not integrated your earth pits,
connect all the four earth pits with 50X8 GI flat.
now check earth pit resistance is with in limits.

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What will be the voltage regulation of a full load and 0.80 power factor lagging load transformer when a two winding single phase transformer has a voltage regulation of 4.5% at full load and unity power factor?

743


What is the difference between shortcircuit current, rated current of cable & MCB with example? What will be the size of cable required for 5.5 KW motor (Full load current 10 Amps approx.), Starting current with DOL is 120 Amps. Aprrox. Short circuit current with LLLG fault is 2000 Amps Approx.

1587


i have some screw comprressor with 630kw power,i have established them with simple star to delta circuit,by the way there is so much inertia when the screw comprressors start, can you offer me contactors power with 400vac or any cataluge to choose the contactors

1411


in shunt clippers why a resistor is used in sereis with the input

1513


What is relation between mu(nought) and epsilon(nought)?

880






Which test will be more severe for VCB?

2225


What kinds of decision are made about CT from it's Knee point(voltage & current)?

3811


What is the difference between the transmission line and distribution line?

667


what is the main parts of transformer? how it is functioning? pls giv the ans briefly.

1460


What is mean by Sensitive Earth fault & what are the effects

3753


What will be the current drawn by HT motor, if low voltage is applied.. any formula to calculate the LT amps of HT motor.?

1014


What is the RME and explain the full form and what is the RME work?

2115


What is resolver and glass scale in CNC how they work?

1748


What is difference between isolator and circuit breaker?

622


state types of reflectors in illumination engg. ???????

1465