Section insulators are the component in overhead contact lines which separate two sectioning groups or feeding sections, and designed according to IEC60913 with minimum air clearance 150mm for 25 kV system.
As components of overhead catenary system are subjected to suffer aging, electrical and mechanical wear, depending on the period of use and magnitude and duration of the load. Knowledge of wear and aging processes are essential for maintenancemanagement .
The passage of pantographs over section insulators causes wear of the runners because of the following three points:
1. Increased contact forces.
2. Loosening of bolt connections.
3. Commutation processes.
The third one cause arcing, which moves upwards to the arcing horns and then extinguishes.
The material erosion occurring at arcing entry and exit points requires regular inspection and component replacement if needed.
Section insulator runners in overhead contact line installations suffer high wear rates as shown. Consequently, Installation of section insulators in overhead contact lines should be avoided as much as possible.