INTRODUCTION
GIS maintenance ensures that all components function effectively, both electrically and mechanically, over time. Maintenance and diagnostic tests are essential to assess the equipment’s condition and can be classified into two types: online tests and offline tests. The inspection results must be systematically recorded in a database management system (DBMS) for effective monitoring and analysis.
Maintenance Types
- Time-Based Maintenance:
- This approach involves scheduled maintenance based on the aging of materials and the environmental conditions where the equipment is installed. It focuses on preventing potential failures by replacing or servicing parts at predefined intervals.
- Condition-Based Maintenance:
- This strategy involves monitoring the equipment’s condition to identify components that require attention. Maintenance is performed only on parts showing signs of wear or degradation. This method allows for targeted repairs, extending the life of components and reducing unnecessary downtime.
Wear and Aging Considerations
- Internal Components:
GIS internal parts are housed in a protective metal enclosure, reducing exposure to environmental factors and slowing down aging compared to Air-Insulated Switchgear (AIS). Proper material selection and lubrication further minimize wear and aging, even for components like switch contacts. - High-Wear Components:
Circuit breaker arcing contacts and interrupter nozzles may wear more quickly due to frequent operations and high load or fault currents. These parts require regular monitoring and potential replacement to maintain reliability.
Maintenance Requirements
- Accessibility:
Major components like circuit breakers and disconnect switches should be repairable without removing them from the gas-insulated enclosure, whenever feasible. However, if removal is necessary, it should cause minimal disruption to the rest of the system. - System Design Considerations:
GIS equipment should incorporate sectionalizing features or partitions to allow isolated maintenance. Temporary protective covers may also be used during repairs to ensure the integrity and safety of the system.
Recommendations
- Use high-quality materials and lubricants to minimize wear and extend the operational life of components.
- Regularly inspect and record data on critical components, focusing on high-wear areas like arcing contacts and nozzles.
- Ensure design flexibility in GIS systems to facilitate maintenance with minimal impact on system operation.
- Utilize advanced monitoring tools for condition-based maintenance to optimize equipment reliability and reduce costs.
