Why HRG and LRG used beside transformer, what is the purpose
Answers were Sorted based on User's Feedback
Resistance Grounding falls into two categories: Low
Resistance and High Resistance
1) In Low Resistance Grounded (LRG) Systems the current is
limited to 25 amps or more. Generally the range is from 25
to 600 amps, although in some systems it may be even
greater.
2) In High Resistance Grounded (HRG) Systems the current
is limited to 10 amps or less.
------------
A) On systems with a voltage of 1000 volts or less (phase-
to-phase) grounding resistors are not used. Normally these
system use a solidly grounded configuration with no
intentional impedance being introduced into the system.
B) Resistance Grounding is recommended on Medium Voltage
Systems from 1000 volts to 15,000 volts phase-tophase.
C) Because of the cost, Resistance Grounding is not usually
used on systems above 15,000 volts phase-to-phase.
Additionally, the use of a solidly grounded system allows
for use of equipment which is insulated for the
phase-to-neutral voltage of the system.
·D) When a system has protective relays which will trip the
circuit if a ground fault occurs, a grounding resistor with
a 10 Second Rating is often specified, because the relays
will trip the system in less than 10 seconds.However, One
Minute or Ten Minute ratings are sometimes used for an
extra margin of safety, even though the cost will be
greater.
Is This Answer Correct ? | 5 Yes | 0 No |
Resistance Grounding falls into two categories: Low
Resistance and High Resistance
1) In Low Resistance Grounded (LRG) Systems the current is
limited to 25 amps or more. Generally the range is from 25
to 600 amps, although in some systems it may be even
greater.
2) In High Resistance Grounded (HRG) Systems the current
is limited to 10 amps or less.
A) On systems with a voltage of 1000 volts or less (phase-
to-phase) grounding resistors are not used. Normally these
system use a solidly grounded configuration with no
intentional impedance being introduced into the system.
B) Resistance Grounding is recommended on Medium Voltage
Systems from 1000 volts to 15,000 volts phase-to phase.
C) Because of the cost, Resistance Grounding is not usually
used on systems above 15,000 volts phase-to-phase.
Additionally, the use of a solidly grounded system allows
for use of equipment which is insulated for the phase-to-
neutral voltage of the system.
D) When a system has protective relays which will trip the
circuit if a ground fault occurs, a grounding resistor with
a 10 Second Rating is often specified, because the relays
will trip the system in less than 10 seconds. However, One
Minute or Ten Minute ratings are sometimes used for an
extra margin of safety, even though the cost will be
greater.
Is This Answer Correct ? | 3 Yes | 0 No |
Answer / john
HRG - High resistance grounded.
LRG - Low resistance grounded
Is This Answer Correct ? | 2 Yes | 0 No |
How does a diesel generator works?
what is the use of cable in our environment ?
What is the difference between a Junction Box and a Marshalling Box?
What is clean Earth System ?
in 220 kv substation,what is the mean of avr voltage reading? means at oltc temp. 36 the avr voltage was 109v.so what the mean of 109v
why America use 60HZ 110V?
advantages & Disadvantages of Solar power system?
AP Transco Assistant Engineer (Electrical) Model Question papers
2 Answers APTransco, HCL, Tranco, UPSC, VMware,
i asked a funny question in Electrical ohms law V=IR in const temp voltage is directly proportional to current Power p=VI cos@ in that formula Voltage is indirectly proportional to current Try to give me the fact what is happening in Electrical.. contact Thanigai_1984@yahoo.co.in
11kv/0.433kv, 2 mva , transformer , for protection and metering how many CT/PT are required?
Why magnetic flux produces an induced current?? what is the detailed procedure ?? ans plz
how electrical earthing maintenance done in industry?