Keywords: high voltage insulator installation, insulator operation and maintenance, insulator cleaning, porcelain insulator, composite insulator, glass insulator, insulator inspection cycle, insulation resistance test
Abstract: Systematic introduction of high voltage insulator installation technical specifications and daily operation and maintenance requirements, covering installation differences, inspection cycles and testing standards for three types of insulators: porcelain, composite and glass.
High voltage insulators are not only bearers of electrical insulation but also mechanical supports for conductors. Their operating status directly affects the safety and reliability of transmission lines. Standardized installation and scientific operation and maintenance are key to extending insulator service life and reducing failure rates.
I. Three Common Types of Insulators
1. Porcelain Insulators
Made primarily of electrical ceramics, this is the most traditional type of insulator. It has excellent electrical and weathering performance, low cost, but is heavy, fragile, and has poor anti-pollution flashover capability due to surface hydrophilicity.
2. Glass Insulators
Made of tempered glass, featuring zero-value self-explosion characteristic - when insulation performance is lost, they shatter automatically, facilitating inspection discovery. They have high mechanical strength, but the self-explosion rate must be controlled within a reasonable range.
3. Composite Insulators (Silicone Rubber Insulators)
With epoxy fiberglass core rod as the inner core and silicone rubber as the outer housing and sheds. They are lightweight, highly hydrophobic, have excellent anti-pollution flashover performance and are not easily shattered. However, after long-term operation, problems such as shed aging and housing cracking may occur.
II. Installation Technical Specifications
1. Pre-installation Inspection
- Porcelain insulators: check for cracks, pinholes, glaze defects on the glaze surface, and looseness at the porcelain-metal cementing points
- Glass insulators: check for self-explosion fragments and integrity of steel cap cementing
- Composite insulators: check for shed tearing damage, secure hardware connections, and housing detachment
2. Installation Requirements
- Clean surface dirt from insulator strings before installation, keep clean and dry
- Bolts, pins, cotter pins and other connectors should be complete and correctly installed, none omitted
- Socket cap mounting plates of suspension insulator strings should be in the same direction, cotter pin opening angle not less than 60deg
- Installation torque should comply with manufacturer specifications, use torque wrench for tightening
- Do not strike the insulator body with metal tools during installation
3. Acceptance Standards
- Insulator string fully assembled with reliable connections
- All bolt tightening torques qualified
- Insulation resistance test passed (≥500MΩ for below 35kV, ≥1000MΩ for 110kV and above)
- Clean appearance without damage
- Installation position consistent with design drawings
III. Daily Operation and Maintenance Management
1. Inspection Cycles and Methods
- Regular Line Patrol: Cycle determined by line voltage level and importance, generally monthly or quarterly
- Night Patrol: At least 1-2 times per year to detect corona discharge not easily visible during daytime
- Special Patrol: Should be arranged promptly after severe weather such as strong winds, heavy rain, ice, snow, smog, etc.
- Drone Inspection: Rapidly developing in recent years, can efficiently capture high-definition images for intelligent analysis
2. Inspection Points by Type
| Insulator Type | Inspection Item | Cycle | Qualification Standard |
|---|
| Porcelain | Zero-value Detection | 2 years | Resistance ≥300MΩ |
| Composite | Hydrophobicity Test | 3 years | HC1-HC3 level |
| Glass | Self-explosion Rate Statistics | Real-time | Annual self-explosion rate ≤0.2% |
3. Cleaning Maintenance
Insulators in heavy pollution areas should be cleaned regularly. Either outage manual cleaning or live-line water washing can be used. During cleaning, care should be taken not to damage the insulator surface glaze layer or silicone rubber layer. Specialized equipment and deionized water are required for live-line cleaning.
IV. Insulator Replacement Timing
- Porcelain insulator glaze peeling area greater than 10mm2
- Composite insulator shed has penetrating cracks or severe housing detachment
- Insulation resistance test fails to meet specification requirements
- Zero-value or low-value insulators found during periodic testing
- Mechanical damage affects structural strength
Safe operation of insulators requires full-chain management from installation, inspection, testing to replacement. Negligence at any link may lead to insulation accidents.
1
