How to replace Insulator String?
Insulator String replacement varies as per tower configuration, insulator type & voltage level.
How to improve efficiency of Insulator Strings?
Insulator failures can be avoided by improving the efficiency of Insulator Strings. If rights steps are taken the life and efficiency of Insulator Strings can be improved.
- Periodically cleaning of disc insulators.
- Preventive Diagnosis.
- PID scanning.
- Regular conducting Megger test.
- Eliminating Flashover discs from string.
Causes of Insulator Failure:
a) Cracking of insulator- The main cause behind insulator failure is because of cracking of insulator. Insulator cracking happens because of stress produced in the porcelain due to unequal expansion and construction produced in cement, steel and porcelain. All these things are caused by seasonal heat-cold, dryness, and dampness or by heating of the insulator. To avoid cracking of insulator, many improvements in the designs have been made, like cushions are placed in between shells and steel pins in order to allow for its expansion.
b) Defective of materials- If the material is defective anywhere, it will puncture and becomes unfit for further use. So defective material is one of the causes behind insulator failure.
c) Porosity of the materials- If the porcelain is manufactured at lower temperatures, it will make it porous. Because of this the porcelain will absorb moisture from air or from cement and thus becomes unfit for further use. Over the time it becomes one of the mains reasons of Insulator failure.
d) Improper glaze- If material is not properly glazed, the water will stick to it which will result into deposition of dust etc. over it which is partially and reduces the flashover distance. Causes the insulators to be damaged.
e) Flash over- If there is a flash from one metal part to other, it will cause over-heating and will result into shattering of it.
f) Mechanical Stress- The pulling of the insulator may also sometimes cause mechanical stress in it (if its material is defective) due to which it may break and causes insulator failure.