Switchgear acts as the primary control and protection system for the electrical power supply. Though electrical switchgear is made to operate with low maintenance, regular inspection is required to provide safe operational conditions and avoid costly downtime. This article gives a comprehensive overview of best practices in maintenance, including safety factors, inspection schedules, and principal maintenance operations.
Safety Considerations
Electrical equipment maintenance comes with inherent dangers, and hence safety is a priority. Supervisory staff and engineers should be familiar with industry and local statutory requirements. Live work should never be done. In case of a fault, only a competent electrician should perform diagnostics and repairs. For added safety, shutdown procedures, schematic diagrams, and instructions should be clearly posted in the switchroom. These tools assist operators in performing maintenance safely and verifying proper isolation practices are implemented.
Maintenance of New Switchboards and Switchgear
First Inspection and Commissioning
New switchboards must be thoroughly inspected before commissioning and inspected again during the first 12 months of service. Basic checks include ensuring fastening and conductor terminal tightness, checking internal cleanliness to avoid flashovers, checking insulation integrity, testing circuit breaker operation and mechanical interlocks, and checking weather seal, gasket, and protective coating condition.
Thermographic Surveys
On commissioning and subsequent to any modifications in the circuits, thermographic surveys must be performed. Because switchboards are connected to on-site external conductors, hot spots and overloading of the circuits can occur. Infrared thermography will help identify overheating problems early on, thus lowering the possibility of failures.
Functional Testing
The testing procedure must involve ensuring circuit breakers work properly by means of the trip button test and that residual current devices (RCDs) trip on fault conditions at intervals specified in the industry.
Routine Maintenance Schedule
Annual Maintenance
A thorough check must be done every 12 months to check for insulation discoloration or brittleness, inspect and tighten all cable connections, test control wiring and replace damaged portions, clean draw-out parts and air filters, check indicating devices and mechanical interlocks, and exercise circuit breakers manually to avoid contact corrosion.
Ten-Year Maintenance Plan
At the end of a decade of operation, more extensive maintenance is necessary, such as torquing primary conductor connection bolts to the manufacturer’s specifications, tightening all secondary control wire connections, inspecting for loose lug crimps and damaged insulation, performing insulation resistance and functional testing, and assessing the replacement of obsolete components based on reliability, availability of spare parts, and maintenance cost.
Post-Fault Maintenance
Once a circuit breaker has tripped in fault condition, it should not be reclosed unless there is a serious investigation of the cause. Diagnosis by a skilled electrician, checks on the mechanisms of circuit breakers, and insulation resistance testing should precede re-energization of switchgear.
Record Keeping and Performance Tracking
Keeping accurate records promotes equipment lifespan and effectiveness. The records must reflect the equipment’s condition for each inspection interval, maintenance details, and specific areas that may need future inspection or attention.
Planning the Frequency of Maintenance
Manufacturer’s Recommendations
It is advisable that the maintenance frequencies coincide with manufacturers’ recommendations. A few producers have maintenance guides with time-related schedules, counts of switching activities, or based on environmental aspects.
New Commissioned Equipment
Switchgear must be inspected prior to commissioning and also after 12 months to guarantee reliability and identify any early signs of degradation.
Major Considerations During Inspection
Subsequent inspection cycles need to be set according to outside contamination of insulation, interior insulation and oil status, wear in contact points and arc-control device integrity, operation of mechanism and lubrication, weather seal integrity, and rate of corrosion.
Recommended Maintenance Intervals
Indoor Switchgear
In clean, dry, and ventilated conditions of installation, inspection is to be carried out every 12 months, examination every five years, and overhauls every 10 to 15 years, depending on inspection results.
Outdoor Switchgear
Outdoor pollution or coastal area switchgear must be inspected more often because of environmental degradation. Changes accordingly.
High-Use or Harsh Environment Applications
In case of switchgear subjected to repeated switching operations, i.e., in electric arc furnaces, maintenance may be done as often as every few weeks. Maintenance must in such instances be in terms of number of operations and not time intervals.
Switchboard Maintenance Checklist
Visual Inspection
Routine inspections would involve checking for damage, overheating, corrosion, and loose connections with no foreign material or debris inside the switchboard enclosure.
Cleanliness
Parts and surfaces must be kept clean by dusting off dirt and dust, using compressed air or vacuum equipment to clean out debris.
Connections and Wiring
All electrical connections should be tightened and any defective wiring or insulation should be inspected and replaced as necessary.
Environmental and Enclosure Inspection
There has to be an adequate ventilation for the purpose of avoiding overheating, and sealing must be inspected for moisture ingress or contaminant entry.
Training and Safety Compliance
There has to be an adequate supply of safety training provided to maintenance personnel, and also personal protective equipment (PPE) has to be supplied.
Low voltage electrical switchboard proper maintenance is critically important for effectiveness, dependability, and security. By complying with regular routines of systematic schedules, proper inspection, and recording, organizations minimize the risk of failure and maximizes the lifespans of their electrical infrastructures.
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