Troubleshooting LV-Panels


Indications (Phase & Status) not coming on Switchboard

Probable Causes Solutions
Power Supply not connected to switchboard Connect Power Supply to the Incomer Breaker
Control MCBs for Indication Ckt. are off or Control Fuses are blown off Switch "ON" the MCBs or replace Control Fuse Links whichever is applicable
Indicating Lamps are faulty Replace Indicating Lamps
No Control Supply Available Check for rated Control Supply to the switchboard at the terminals provided as per wiring drawing.

Probable Causes Solutions
Closing on Short Circuit Remove the fault after detection and than close the Circuit Breaker after inspection of circuit breaker condition
ACB is not completely in Service Position Check whether ACB spring is charged*
Check whether U/V Release is picked up
Check for any Mechanical or Electrical Interlocking
Check whether Trip command is issued by any Feeder Protection Relay/Device & resolve.
Reset Button Signalling a Fault Trip has not been reset Remove the fault after detection and than close the Circuit Breaker after inspection of circuit breaker condition
No Control Supply Available* Connect rated Control Supply to the switchboard at the terminals provided as per wiring drawing.
Control MCB is "Off"* Switch "ON" the Control MCBs
Selection for Local Mode is not done* Select Local Mode
Closing command not executed by Closing Coil Check the voltage and the supply circuit, if problem persists replace the Closing Coil
Interlocking Ckt. Not working Check for proper control voltage/Micro PLC UPS Supply. If problem persists contact STANDARD CONTROL PANEL PVT. LTD. Mobile: +91-98764-00718, +91-99884-20003
Plug-in terminals provided at Transport Section not connected Connect the Plug-in terminals
Breaker Control Switch Faulty Replace faulty Breaker Control Switch.

Probable Causes Solutions
Opening command not executed byTripping Coil Check the voltage and the supply circuit, if problem persists replace the Tripping Coil
Welded contacts of the Circuit Brekers Contact STANDARD CONTROL PANEL PVT. LTD. Mobile: +91-98764-00718, +91-99884-20003
No Control Supply Available Check for rated Control Supply to the switchboard at the terminals provided as per wiring drawing.
Breaker Control Switch Faulty Replace faulty Breaker Control Switch.

Probable Causes Solutions
Circuit Breaker in Closed/On condition Open the Circuit Breaker

Probable Causes Solutions
Presence of any Rack In/Out Interocking Follow correct Interlocking sequence

Probable Causes Solutions
U/V Release supply too low Check the voltage and the supply circuit, if problem persists replace the U/V Release
Wrong operation sequence done manually Follow the correct operation sequence and restore supply
Tripping on Fault (i.e. Overload, Shortcircuit, Earthfault) Remove the fault after detection and than close the Circuit Breaker after inspection of circuit breaker condition

Probable Causes Solutions
Feeder SCPD i.e.(MCCB, SDFU, MCB) is in 'OFF' condition Switch'ON' the Feeder SCPD
Thermal O/L relay is in Trip Conditon Reset the O/L relay by means of reset push button on the relay
Start push button is not working properly Check start push button element for proper working
Local Mode selection not done Select Local Mode through selector switch provided on Feeder Door
Any interlocking is preventing the Starter Operation Check for proper operating seqence.

Probable Causes Solutions
Primarly Check for any probable cause as covered under Starter Operation Locally. Resolve the problem as suggested above
Remote mode selection not done Select Remote Mode through selector switch provided on Feeder Door
Any wiring fault for remote close command Check for Fault and resolve.

Probable Causes Solutions
No Control Supply Available Connect rated Control Supply to the switchboard at the terminals provided as per wiring drawing.
Control MCB is "Off" Switch "ON" the Control MCBs

Probable Causes Solutions
No Power Supply Available Connect Power Supply to the Feeder
Control MCBs for PT Ckt. are off or Control Fuses are blown off Switch "ON" the MCBs or replace Control Fuse Links whichever is applicable

Probable Causes Solutions
CT shorting terminals provided in Metering Feeder are still short Open the shorting link by loosening and sliding down the shorting link
No load on the Feeder Can be checked after putting some load on the feeder.

Probable Causes Solutions
SCPD (i.e. MCCBs, SDFU) for the Capacitor Bank Feeder is in 'OFF' condition Switch 'ON' the SCPD for capacitor bank feeder
C.T.shorting link is not open at Trf. End. Open the C.T. shorting link
Auto' selection not done for Capacitor Bank Feeders Select 'Auto' mode for Feeders by selector switch provided on the feeder door
APFC Relay not in 'Auto' mode. Put the relay in 'Auto' mode. Refer the Relay User Manual
Sensing current to the relay is too low. Opt for a suitable rating Fixed Capacitor Bank. Consult STANDARD CONTROL PANEL PVT. LTD. Mobile: +91-98764-00718, +91-99884-20003
Capacitor Bank are faulty and rejected by APFC Relay Replace Capacitor Bank. Consult STANDARD CONTROL PANEL PVT. LTD. Mobile: +91-98764-00718, +91-99884-20003
Pre programmed parameters disturbed at site Check for current programmed parameters and correct if required or cont. STANDARD CONTROL PANEL PVT. LTD. Mobile: +91-98764-00718, +91-99884-20003

Probable Causes Solutions
DG is not started after Set Time Delay Check for Released Emergency Push Button, key in 'ON' condition.
No Control Supply Available Check for rated Control Supply to the switchboard at the terminals provided as per wiring drawing.
Start Command Not Executed by DG Set Contact respective DG Service Centre
D.G. set is not in Remote mode Put the D.G. in Remote mode by D.G. controller or cont to D.G. vendor
AMF Relay not in 'Auto' mode. Put the relay in 'Auto' mode. Refer the Relay User Manual
Fault Signalled by relay Attend and resolve the fault. If the problem persist call STANDARD CONTROL PANEL PVT. LTD. Mobile: +91-98764-00718, +91-99884-20003
Standard Control Panel Private Limited