Magnetic valve fails to operate
(1) Valve locked at low-pressure     position.
Raise pressure.
(2) Coil burnt and open circuit
Replace coil
(3) Limit switch malfunctioning,
Adjust pressure on limit switch or replace it.
Magnetic valve stops halfway
(1) Drop in control pressure.
Raise pressure.
 (2) Circuit closing and       circuit opening magnetic
valves operate       
Temporarily turn off control power source
and operate valve again.
(3) Magnetic valve will not self-hold.
Terminal P not supplied with (+) power (Turn on (+) power). Limit switches out of order (refer to descriptions on limit switch).
Magnetic valve fails to stop automatically (electric circuit is kept energized)
(1) Improper pressure on limit switches

Adjust pressure on limit switches.
 (2) Limit switches  
malfunctioning (contact metal dposited).
Replace limit switches.


Gas leak
(1) Packing for sealed part incompletely fitted into groove, and packing is ruptured.
Replace packing for sealed part.
(2) Welded part is defective, and welding material is defective.
Reweld and replace parts.
(3) Tightening of welded part    insufficient.
Check on tightners.
(4) Gas density detector malfunctioning.
Readjust or replace gas density detector.
Air leak
(1) Air leak of magnetic valve.
(a) Valve packing damaged by foreign matter that has infiltrated valve.

(b) Valve seat damaged by foreign matter that has infiltrated valve.

(c) Magnet valve lever broken.

 (a) Replace valve    
      foreign matter.
 (b) Replace valve  

 (c) Replace lever.
(2) Air leak from Same as (a) and (b) above.main valve.
Same as (a) and (b) above.
 (3) Air leak from piping system.
Check on tightness.
(4) Increased amount of air leakage fromairin valve.
Measure discharge of airing valve. If not specified valve, replace airing valve.
(5) Others.
Check packing and check on connections.

Possible Causes
Possible Remedial
Low insulation Resistance
(below 2000 Mega-ohms) between
-  Phase terminal and grounded frame, with breaker closed
-  Phase terminals of a pole.
- Moisture
- Dirty insulation surface  
  internal and/or external
- Poor oil
- Carbon/copper particles
sticking to internal surface
 -  Circulate dry hot air or oil through the breaker pole for 4 to 6 hours.
- Dismantle, clean, reassemble insulation resistance should be above, 2000 Megaohm, for 1.1 kV and above 10,000 megaohms above 36 kV
Resistance between Terminals of Pole too high
(above 100 microhms) (15 microhm per joint) contact
- Reduced contact  
- Loose connections
- Contact surface damaged
due to repeated operations
- Insufficient contact  
- Oxide film on contact
- Dismantle, repair and as
semble again. If necessary, replace the contacts
Unequal contact Wipe andTravel in 3-pole Measured from top surface of interrupter flange and the contact tip by a simple rod with
- breaker open
- breaker closed
- Contact erosion due to  
peated load operations or
short circuit operations
- Unequal length due to  
   Wrong  adjustments  of
- Inspect contact tips
- Replace if badly eroded
- Adjust contact if lengths are unequal in three pole
One of the pole does not close
-      Pull rod for contact damaged
-      One the links of that pole broken.
-      Contact of that pole severely damaged
-    dismantle the pole and repair the defect.

Breaker operation too slow during opening (Timing from trip command to contact separation instant too large (60 ms intead of say 40 ms)
-      Excessive friction in the pole unit.
-      Contact grip to high.
-      Trip coil operation sluggish.
-      Low battery voltage, hence higher trip coil pick-up-time
-      Chech control circuit.
-      Chech closing spring visually.
-      Indentify the cause and take remedial action
-      Check supply to spring changing motor.
-      Check pressure switches, relays, control wiring.

ANN Item
Probable Cause
Action and/or Countermeasure
230 kv gen, transf
breaker tripped
 1. lock out relay BTG
 2. Pole discrepancy

Confirm the operated relay(s) by the taget on P.R.P.
230 kv gen, transf, breaker
trip circuit unhealthy
230 kv gen. trans.
breaker. Trip circuit
1.Circuit breaker gas and/or air pressure
2.Failure of aux, relay circuit.
1. Check gas pressure and /or air pressure.
2. Check the auxiliary relay circuit by circuit tester.
  230 kv gen.    
  transf. breaker
air and gas- press. Low
230 kv gen. transf.
breaker, 30ACB,
30GCB, 30G1
1.Gas and/or air pressure low.
2. Gas and/or air valve fault.
3.Fault of air compressor.
1. Check gas pressure and/or air pressure.
2. Check if any leakage in values and/or piping.
3. Check the operating condition of air compressor.
230 kv gen. transf- BXR
pole discrepancy.
230 kv gen, transf,
1.Circuit breaker aux. contact failure.
2.Timer Tix fault.
1. After disconnecting the circuit breaker from thesystem,
    operate the breaker and check the circuit by tester.
2. Check the operating time of the timer.
230 kv gen. transf. BXR
incomplete transfer
( MTS),
switch circuit.
No change over operator, of MTS switch
to final "BUS TIE" position even when
the close of bus tie breaker is completed.
 1. Check the MTS switch position as "TRANSFER" and change over it to "BUS TIE" position to open the breaker being transferred.
 2. Check if any looseness in the MTS switch circuit by tester.
 3. Check the MTS switch circuit by tester.

معلومات عن التدوينة 21 فبراير 2014 عدد الزيارات: (850) عدد التعليقات: 2 الكاتب:iHussam للإبلاغ عن رابط معطوب اضغط هنا للإبلاغ عن رابط معطوب اضغط هنا جميع الحقوق محفوظة ( إتفاقية نقل ونشر المحتوى )

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