Preventive Maintenance and checklist

HV END CONNECTOR

Preventive maintenance checklist  

                                                 

 Why Perform Preventive Maintenance on Electrical Systems 

During the winter and summer months, power requirements are higher for many industries as facilities struggle to keep buildings warm and their assets in operation. In addition, in today's economic environment, facility and plant managers also struggle with efforts to lower power consumption in order to reduce expenses.

 Reasons to Perform Electrical Preventive Maintenance

 

THERE IS SAYING ‘A STITCH IN TIME SAVES NINE.’

1.       Avoid electrical shorts that cause fires: Electrical short circuits can occur when wires are overloaded with current, wires are exposed and load imbalances. This can cause excessive heat build-up, arcing or explosions.

2.       Identify loose connections: Loose connections can cause power fluctuations to devices, devices to operate erratically and uneven load distribution between wires.

3.       Identify components running hot or not according to specifications: Transformers, motors, bearings and wires almost always run hot before they fail. Predictive maintenance technologies such as infrared Thermography, vibration analysis and laser alignment tools as well as general maintenance such as regularly scheduled lubrication can avoid asset failure.

4.       Identify unusual smells, noises, dust build up, or discoloration: Melting insulation, stressed motors, corrosion through dust and so on make a physical inspection a requirement for electrical components. Electrical troubleshooting and simulation should be performed using a systematic approach.

5.       Check all emergency lighting, signage and power indicator displays: Many electrical disasters occur when the safety monitoring equipment itself is faulty leading to a false belief that all is ok.

6.       Extend the useful lifecycle of assets: Poorly maintained assets require more energy to do the same amount of work. This leads to excessive wear and tear and a shortening of the assets useful lifecycle.

7.       Avoid unplanned downtime: Unplanned downtime can shut down production, result in emergency labour costs and unnecessary capital asset replacement. Without proper electrical training, all of these significantly impact the profitability of the organization.

8.       Less equipment loss: Consistent electrical preventive maintenance will reduce the amount of equipment that needs to be replaced early as a result of electrical problems.

9.       Energy savings: Optimal energy efficiency will occur when equipment is functioning within design parameters and is well maintained.

10.    Safety and Liability: The most important reason of all is safety. Avoiding serious injuries or death is worth every penny spent on prevention. Liability lawyers have a field day when facilities have a poor maintenance record.

 

How Often Should Electrical PM be done?

 

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Electrical systems should have a thorough inspection by a qualified electrician. The frequency –quarterly, half yearly, annually, bi-yearly so on. It depends on the service of the equipments and decision should be taken by section head.  Individual assets should be inspected according to manufacturer directions or based upon experience and industrial training in a particular environment. For example, some motors may need to be inspected quarterly, air handlers annually and so on. Preventive maintenance, inspections and work orders are best handled using your own excel sheet or specialised software for the scheduling and recording of activity, results and notes.

Preventive maintenance of electrical systems goes beyond the visual or scheduled predictive maintenance work. A full electrical PM is a complete look at the electrical system including;

Sample Electrical PM Items

o    Compliance to safety audit recommendation

o    Re-torque connections

o    Checking panel boards

o    Inspecting control logic/scheme/PLCs for effectiveness

o    Examining work orders as well as new installs for compliance and uniformity

o    Making sure lock-out tags are in place

o    Inspection of heating and cooling units

o    Lighting

o    Shutdown mechanisms

o    NEC code compliance

Electrical inspection checklists and resources

Every organization has a unique set of assets. Therefore, it is unlikely that the same electrical inspection checklist will be the same. Generally manufacturer provides the checklist for maintenance it should be adhere to or with own practice we can develop ourselves.

GENERAL ANNUAL CHECKS

(1) Review past maintenance records to find repair patterns. These records may point to certain components that should be closely inspected during performance of preventive maintenance.

(2) Review operator records concerning electrical load readings; compare with equipment ratings. Operator records regarding operating temperatures and any documented abnormal circumstances associated with the system should also be reviewed.

(3) Inspect Secondary Electrical Distribution Equipment:

(a) Inspect to ensure that warning signs exist. Replace as required. (b) Inspect enclosures for damage, unauthorized openings, and corrosion of metallic objects. Repair and paint as required. (c) Inspect air passages and remove any blockage. (d) Inspect, investigate, and solve conditions for unusual odors. (e) As equipment is operated and tested, listen, investigate, and solve conditions for unusual noises. (f) Inspect electrical connections for degradation and tightness. Repair as required. (g) Inspect electrical insulation for discoloration and degradation. Repair as required. (h) Inspect equipment grounding components such as conductors and connections. Repair as required. (i) Inspect insulators for damage. Replace as required. (j) Inspect liquid immersed equipment for leaks and damage. (k) Inspect indicating lights for correct illumination.

(4) Remove debris, dirt, and other foreign objects from all components, housings, cabinets, panels, etc.

(5) Torque all electrical connections to design value..

(6) Verify operation of space heaters and control thermostat. Check thermostat set point for proper setting.

(7) Verify the grounding of the equipment and associated neutral where applicable.

(8) Conduct infrared test on all main current carrying equipment for hot spots that may indicate overload conditions or loose connections.

(9) Using calibrated test instruments, calibrate ammeters, voltmeters, etc.  Verify continuity of metering selector switch contacts with ohmmeter.  Sample

Check List for Transformer Maintenance

Date:                                      

Substation No:                                               

Transformer No:                                                          Voltage Ratio:                                    

Slno	Activities	Checks carried	Remarks
1	Obtain LC from Sub-station Operation
2	Check for oil leakages
3	Check for oil level in the conservator tank is up to 3/4th mark
4	Check for Breather condition
5	Check for Silica Gel condition
6	Clean the body
7	Open the terminal box check the following a)      Tightness of terminal connection b)      Condition of bushings c)      Any sign of overheating.
8	Check for any unplugged opening, missing bolts
9	Check all terminal box tightness
10	Check oil/winding temperature setting
11	Check earthing system is proper & intact
12	Check cable support
13	Check IR value a) Primary         : P-E b) Secondary     : P-E
14	Any other abnormality

Signature

Check List for Switch Board Maintenance

Date:                                      

Substation No:                                               

SWB No:                                                                         Rating:                              

Slno	Activities	Checks carried	Remarks
1	Obtain LC from Sub-station Operation
2	Ensure isolation of the Incomer and Bus coupler breaker and control supply and Heater supply of the section
3	Ensure all back feeding sources are isolated
4	Remove all breakers/modules and PT Cubicles (If it is draw able type)
5	Open the top and side covers of the busbar chamber.
6	Clean the busbar chamber, breaker rear and front compartment with air blower, vacuum cleaner and dry cloth.
7	Clean all insulators by soft dry cloth & contact Cleaner. Check for cracks, damages & replace the defective one.
8	Check and tighten the exposed joints of the busbar. Check for any signs of heating.
9	Check and tighten the power connections of CT/ PT  and out going cables.
10	Check for any unplugged opening, missing bolts
11	Box up busbar chamber & rear compartments of breaker.
12	Check earthing system is proper & intact
13	Check IR value a) R-E       b) Y-E    c)  B-E
14	Any other abnormality

Signature