Common Faults and Solutions of Switchgear
1. Common faults of switchgear
(1) Switchgear reject closing.
(2) Switchgear reject opening.
(3) The red light is out.
(4) The green light is out.
(5) Abnormal sound of current transformer.
(6) Locking failure, in the closing state, the net door can be opened.
(7) The working light of the switchgear is out.
(8) Disconnect switch rejects open and close.
(9) The handcart switch cabinet cannot be closed by remote control.
(10) The indicator of the mechanism opening and closing is not in the right position.
2. Switchgear reject closing solution
The reason why GG1A type switchgear cannot be closed
(1) Improper operation.
(2) The closing power supply loss.
(3) The control circuit is disconnected.
(4) Bad contact of transfer switch.
(5) The closing coil is broken. The closing contactor coil is broken.
(6) Poor contact of auxiliary contact.
(7) Other mechanical faults, such as the connecting rod of the transmission mechanism falling off, the locking iron core sticking, and the mechanism not being reset after the breaker opening.
Solutions:
(1) First of all, when the green light is on, closing it for one more time. If the switchgear is closed, it means that the transfer switch is not in place, which is improper operation.
(2) If the green light is on and the contactor ACTS, check whether the closing power supply is normal, such as the failure of the power switch and the failure of the closing fuse, and deal with the causes.There are two ways to check whether the fuse is fusible: one is for live inspection, the other is for ohmic check after removing.
(3) If the green light is not bright, check the control fuse and the small switch first to see if they fuse or trip.If a problem is found, it should be replaced promptly.
(4) If the auxiliary contacts have poor contact and the green light is not bright, open the cover of the mechanism, check the auxiliary contacts of the closing circuit, and adjust the small pull rod to the qualified position.
(5) The closing contactor coil is broken, or the point is jammed.Replace contactor or remove for repair.
(6) If the transfer switch has poor contact, short-circuit the 5-8 contact and then close the switch, indicating that the contact has poor contact, disassemble, repair or replace it.
(7) Open the cover of the mechanism and use manual closing to check whether the closing rod can pass through the bracket by 2mm. If it cannot be explained that the closing stroke of the iron core is insufficient, the length of the iron core shall be adjusted.
(8) Open the cover of the mechanism and check whether the mechanism returns to its position after the last brake opening. If not, manually reposition it and close it again.
(9) Check whether the voltage of closing power supply meets the rated voltage of not less than 85%.
(10) Spring energy storage mechanism, should adhere to whether the mechanism for energy storage.
3. The reason why KYN28 switchgear cannot be closed and opened
(1) No control power display control circuit is disconnected.
(2) Bad contact of transfer switch.
(3) Spring non-energy storage energy storage indicator light off.
(4) The car did not roll to the position, the car position indicator light off.
(5) Poor contact of aviation plug.
(6) Failure of the control circuit board in the handcar.
(7) The auxiliary contacts and travel switches in the handcar are not in good contact or not in place.
(8) Short-circuit or disconnection of the closing or opening coil.
(9) Mechanical circuit fault (spring, gear, shaft pin, etc.)
Solutions:
(1) If there is no control power display, the control circuit is disconnected. Check whether the power switch of the control circuit is closed. If it is closed, use a multimeter to check whether both the power side and the load side are powered.
(2) Bad contact of transfer switch, check the wiring condition of switch and relevant internal contacts.
(3) Check whether the energy storage indicator light is off, whether the energy storage power switch is off, and whether the hand car is not in place
(4) If the aviation plug is in bad contact, check whether the pin terminal of the plug is in good condition first and whether it is loose or fall off. If so, it should be welded. If the welding is good and there is no loose, it should be inserted and unplugged several times before closing the switch.
(5) The control circuit board in the handcart has faults. There are fuses in four circuits in the circuit board, namely closing circuit, opening circuit, energy storage circuit and closing circuit.The capacity is 5A and 2A respectively. Check whether the fuse is fused, whether the contorter is burned, whether the circuit board wiring is loose, whether the short route is correct, etc.
(6) If the auxiliary contacts and the travel switch in the handcar are not in good contact or not in place, open the handcar panel to manually check whether the contact situation of each contact and the wiring of the contact are in good condition. If the contact is not good, the contact wiring of the contact can be changed or the contact position of the travel switch can be adjusted.
(7) The closing coil or the opening coil shorts or breaks the wire, unplug the coil joint, and measure the coil resistance.
(8) Mechanical circuit fault spring, gear, shaft pin, etc.Check whether the shaft pin is missing, whether the drive shaft is offset or off, whether the spring tension is normal and whether the gear meshing dislocation.
4. The reason why the switch cannot be opened and its solution
(1) The control fuse has blown. Replace it.
(2) Poor contact of 6-7 contacts on the transfer switch.Remove it for maintenance or replacement.
(3) The auxiliary switch in the mechanism has bad contact, or is burnt out.Turn on the mechanism to adjust the length of the tie rod or treat contact burn marks with emery cloth.
(4) Check whether the opening coil is broken, and consider the parallel connection of power supply voltage when replacing.
(5) Check whether the stroke of the gate core is normal, and adjust or replace it if found insufficient
(6) If the iron core is stiff, apply molybdenum disulfide appropriately.
(7) Check whether the dead point is too low. If it is lower than 180 degrees, it can be adjusted appropriately.
5. The reason why the red light of the switchgear is out and its solutions
(1) Use a multimeter to check whether the red light terminal has voltage. If there is voltage, it means that the red light is broken. Contact power failure to replace the red light.(Some lamps have polarity)
(2) If there is no voltage, the opening circuit should be checked, including the transfer switch 16-13 contacts, auxiliary contacts in the mechanism, dividing coil, control fuse, etc.
(3) If it is KYN28 switch cabinet, check whether the power circuit breaker of the control circuit is sent or tripped
6. The cause of abnormal sound of current transformer
(1) The screws fixing the mutual inductor are loose and should be tightened.
(2) Internal core piercing bolts of the transformer are loose.
(3) The small capacity of the transformer results in magnetic saturation when the transformer is overloaded.
(4) Open secondary circuit.For example, the winding of the meter and relay is broken, the connection terminal of the transformer is in bad contact, and the test terminal of the terminal row is open.Treebird education electrical design training
(5) The insulation parts of the transformer are stained, insulation drops, pollution flash discharge.
7. Reason of switchgear lockout failure
(1) The door can be opened after the back brake is closed, and the lock didn't work, check whether the connecting rod fastening screw is loose, adjust it for closing test.
(2) Check the locking between the switch and the disconnector. After closing, whether the ejector rod will press the circular block to the middle of the locking handle of the disconnector. If not, adjust the length of the latching lever of the vacuum switch to make it qualified.
(3) Check the locking of KYN28 switch cabinet. The electrical locking should be powered, and the mechanical locking should have no clamping force. The unlocked door should not be used to open the cable compartment door frequently.
8. The reason why the red light of the switchgear is out
(1) Use a multimeter to check whether the green terminal has voltage. If there is voltage, it means that the green light is bad and you should contact power failure to replace the red light.(Some lamps have polarity)
(2) If there is no voltage, the closing circuit should be checked, including the transfer switch 11-10 contacts, auxiliary contacts in the mechanism, closing contactor coils, control fuses, etc.
(3) If it is KYN28 switch cabinet, check whether the power circuit breaker of the control circuit is sent or tripped
9. The reason why the working light of the switchgear is out
(1) Switch failure, replace it.
(2) If the bulb burns out, replace it.
(3) If the lamp holder is in bad contact, it shall be repaired or replaced after being removed.
(4) KYN28 switch cabinet should be checked for tripping or damage of the power circuit breaker, in addition, check whether the wiring position is in good condition and whether the wiring sheath is pressed in the contact position.
10. The indicator for the mechanism opening and closing is not in the right position
(1) Check whether the opening and closing switch is in place. Check the length change of tension spring and vacuum switch guide rod
To confirm the split and in place, open the cover of the mechanism and check whether the fixing screw of the split and close indicator is loose.
(2) Check whether the indicator for opening and closing is variable-fractal clamping.
11. The cause of the disconnector switch failure
(1) Check whether the insulator of the isolation switch is complete and whether there is corona and discharge phenomenon.Check cement casting connections
In case of any problem, the insulation resistance of the insulator should be tested by megohm meter.
(2) Check whether there are any abnormal phenomena such as damage, rust, looseness or falling off in each part of the transmission rod and mechanism, check the lubrication condition, clean and add molybdenum disulfide when necessary, remove rust and paint the base and ensure it is well grounded.
(3) Check whether the contact is in good condition, whether the pressure of pressing the spring is sufficient, and clean the dirt and burn marks on the contact surface.If the spring of the contact finger is not elastic enough, the contact surface should be coated with neutral vaseline or conductive silicone grease to reduce the oxidation of the contact.
(4) The contact resistance value between dynamic and static contacts and between the bus and the connecting plate of the knife brake should meet the requirements by using the DC bridge.Using this engine the single joint will be 200Q
(5) The standby stroke opening Angle of the retest switch shall be adjusted according to the manufacturer's technical parameters
(6) Check the seal of the operating mechanism of the isolation switch and check whether the interlock is normal.
12. Common failures of vacuum circuit breakers
(1) Loss of vacuum degree and arc extinguishing ability.
(2) The serious wear of the contact of the switch can be observed by the length of the backbar.
(3) The conductive belt has poor contact, the bolts are loose, and the circuit contact resistance is too large.
(4) Loose return spring.
(5) The shaft pin of each part is easy to fall off.
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