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NGK - Suspension Insulators
Insulators are essential to the safe and stable distribution of electricity generated at power plants. Suspension insulators support transmission lines on steel towers, isolating the lines from the tower. They play a key role in the safe supply of electricity. Based on the transmission voltage and usage environment, suspension insulators are used in configurations of two or more.
NGK Suspension (Disc) Insulators have been used successfully in more than 100 countries and in particular have a majority in EHV, UHV and HVDC transmission lines.
Available for any voltage and contamination level by changing number of insulators
- Mechanical strength up to 530kN
- High reliability through accumulated technology
- Excellent long-term performance
Various Types of Suspension (Disc) Insulators.
- Normal type for light contamination
- Fog type for heavy contamination
- DC Fog type for DC transmission line
- Aero dynamic type for desert contamination
High reliability is achieved by long-term experience and accumulation of technology.
Selected High Quality Raw Material
High strength porcelain insulators require not only higher amount of alumina but also
- Management of mining site
- Sufficient technology of material analysis
- Strict incoming inspection - Use only selected material
- Fine and uniform distribution of particles
Optimum Design Engineering
- Straight head design with less stress concentration
- X-3s >= M&E rating with stable mechanical strength (X: average, s: standard deviation in M&E test*)
- Light weight and compact design
- *M&E Test: Electromechanical failing load test as per IEC 60383-1
Advanced Manufacturing Technology
- Automated mass production system
- Uniform quality by continuous firing and production control
- Control of porcelain thermal expansion
- Forming without material damage
- Accurate assembling without stress concentration
Strict Quality Control
In addition to ISO 9001 certified,
- Routine hydraulic pressure test developed by NGK - Effective elimination of manufacturing defects
- Total quality activities of preventive maintenance
Long-Term Performance Evaluation
Thermal-Mechanical (T&M) performance test as per IEC 60383-1 or ANSI C29.2 is to evaluate long-term reliability of insulators.
As these standards specify minimum requirements only, all NGK insulators have been confirmed to pass modified T&M test.
| Test Method | IEC Pub. 60383-1 | NGK Method |
| Load | 60-65% of Specified | 60-65% of Specified |
| E&M failing load | E&M failing load | |
| (24-hour cycle) | (1-hour cycle) | |
| Temperature | -30°C to +40°C | -40°C to +60°C |
| (24-hour cycle) | (8-hour cycle) | |
| Duration | 4days | 15days |
Acceptance Criteria for T&M Test
To exclude poor quality insulators, M&E test results before and after T&M test are:
- No change in strength
- No change in fracture pattern
- No electrical puncture or no shatter
- R-3s>Specified M&E failing load