how to test rotor &stator earth fault in turbine
- 1 Answers
- 11458 Views
- Bhel, I also Faced
- E-Mail Answers
Answer Posted / kannan
STATOR EARTH FAULT PROTECTION :
Setting : 70% Time - 5 Sec.
Normally the generator stator neutral operates at a
potential close to ground. If a faulty phase winding
connected to ground, the normal low neutral voltage could
rise as high as line-to-neutral voltage depending on the
fault location. Although a single ground fault will not
necessarily cause immediate damage, the presence of one
increases the probability of a second. A second fault even
if detected by differential relay, may cause serious damage.
The usual method of detection fault is by measuring the
voltage across the secondary of neutral grounding
transformer (NGT). Here are two over lapping zones to detect
stator ground faults in a high impedance grounded generator
system, the two zones are put together cover 100% stator
winding for earth faults. A fundamental frequency neutral
over voltage relay covers about 0-95% of the stator zonal
winding for all faults except those near the neutral.
Another third harmonic neutral under voltage relay covers
remaining 96-100% of the stator zone 2 winding on neutral side.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.
ROTOR EARTH FAULT PROTECTION (64R) :
Settings : Less than 80K ohm
Any rotor field winding of the generator is electrically
isolated from the ground. Therefore the existence of one
ground fault in the field winding will usually not damage
the rotor. However the presence of two or more ground faults
in the winding will cause magnetic and thermal imbalance
plus localized heating and damage to the rotor metallic
parts. The rotor earth fault may be caused due to insulation
failure of winding or inter-turn fault followed by localized
heat.
Relays acted : a. Flag operation at Protection panel.
b. Acting of Master relay
c. Indication at Annunciation Panel.
Consequences : a. Tripping of 220KV breaker
b. Tripping of Field breaker
c. Stop command to Turbine thro’ Mark-IV
Status : a. Unit is at coasting down.
| Is This Answer Correct ? | 2 Yes | 4 No |
Post New Answer View All Answers
I have a Control VAlve having size of 2 ".Only the known parameter is Pressure drop . Its 2 Kg. Then How to calculate control valve sizing means Cv.
What is three element in drum level?
What is the use of GMV in turbine?
all questions related to instrument technician in any offshore oil and gas company.
what is the criteria to decide conductor size of a cable ?
need to calculate flow rate with the help of dp range and orifice bore dia and size. range is 0 to 400 inwc and orifice size is 12 inch 150 # rf and bore dia is 7.180 inch. need to calculation for flow rate
How to regulate the flow of Air in 4" line, with max flow of 330 nm3/hr and Pressure of 0.5 bar? please suggest the type of instrument required.
What is the use of control cable?
I faced several time siemens ps2 positioner automatically getting Chang in it's set point direction after auto calibration So is there any causes biside this or any permissives ?
what are the documents(Construction point of view for a process plant) submitted by contactor initially entering in to new site for client?
how many type conductivity sensor ?
How to calculate mmwc values into tonnes?
I WANT SECURITY PAPER MILL, HOSHANGABAD TEST PAPER.KINDLY SEND TO MY MAIL ID
Q1]IF THE RANGE FOR FLOW IS -35 TO 125 WHAT WILL BE THE SPAN FOR ABSOLUTE AND FOR NORMAL? Q2]HOW TO CALIBRATE CAPILLARY TYPE LT? Q3]HOW MANY ERROR CALCULATIONS ARE THERE USED IN PROCESS INDUSTRIES? Q4]HOW TO CALIBRATE TEMPERATURE TRANSMITTER? Q5] HOW TO CALIBRATE LEVEL TROLL AND HOW TO CONNECT? Q6]PLEASE TELL ME THE BASIC FOR INSTRUMENTATION WHICH IS APPLIED FOR CALIBRATION AND FOR ALL? PLEASE MAIL THE ANSWER TO honest_yes@yahoo.in
What is the formula of vabration sesore. i mean how to covert mils to volt plz share if any body knows very argent : my mai is merajalam143545@yahoo.com
