what is the difference between earthed system and unearthed
system.. where do we use unearthed system because in
electrical catalogues always cable for earthed and unearthed
system is given..pls elaborate
Answer Posted / s bhattacharya
BASICALLY AS PER LATEST IEC ALL VOLTAGE SYSTEMS WHETHER
400KV OR 415VOLT THE NEUTRAL HAS TO BE GROUNDED AT EACH
LEVEL IN ONE POINT WHETHER SOLID GROUND OR HIGH IMPEDANCE
GROUND.
THE METHOD OF NEUTRAL GROUNDING DEPENDS ON SYSTEM VOLTAGES
1.FOR HV SYSTEMS GREATER THAN 33KV THE NEUTRAL IS GROUNDED
DIRECTLY TO EARTH.
2.FOR VOLTAGES 33KV TO 4kv THE NEUTRAL IS GROUNDED EITHER
THROUGH NGR OR NGT (AS PER THE SYSTEM REQUIREMENT TO LIMIT
THE SYSTEM SHORT CIRCUIT CURRENT IE LIMIT FAULT LEVEL)AND
THIS IS CALLED UNEARTHED SYSTEM.
3.VOLTAGES 415VOLT SYSTEM GENERALLY NEUTRAL IS DIRECTLY
GROUNDED AND THIS IS CALLED EARTHED SYSTEM.
HIGH IMPEDANCE GROUNDING IE FROM 4kv TO 33kV SYSTEMS ARWE
CALLED UNEARTH SYSTEMS AND THIS SYSTEM IS VERY STABLE
COMPARED TO DIRECTLY GROUND SYSTEM.
Is This Answer Correct ? | 9 Yes | 12 No |
Post New Answer View All Answers
What is super thermal power plant? and how it will differ from normal thermal power plant
DRAW ACIRCUIT DIAGRAM OF 100 KVA 415V/55-0-55V DELTA TO STAR TRANSFORMER
what is the difference between dry and wet type of 132kV terminations. which one is durable
what is under coal gassification?
What is Harmonics how it is produced and what is the method to control the same
What are the protection required for Transformer, motor, Line, Generator, capacitor, that all i have to refer which standard?(Like Transformer detail IS 2026)
what are the major & minor faults that occur in an inverter and in UPS ? And how to repair and resolve them ?
difference between main metering kiosk and check metering kiosk
we have consol make 3 phase servo stabilizer for cnc m/c. while installing the earth neutral voltage is 1.7 volts at stbilizer off condition and when stabilizer get on en voltage reaches 4.8 volts (new earthing is done and neutral is helthy condition all phase to neutral volts 440,442,441 v)why this happen.solution for cause.
what is a synchronizing lamp ?
we have provided 30 nos. relay contacts in panel.I want to know how do we do the numbering for the relay contacts as per any applicable standards
What are the classifications of oscillators?
what is meant by 2 within a star in a voltmeter dial?
hwat type of motor is used in thermal gas turbine hydro nuclear power plants and why
details of oil cell size of Breakdown voltage test of tranformer oil details as per Standardswith mushroom electrodes?