Electrical power is often distributed via underground cables as an alternative to overhead cables since underground cables have a longer service life, are less dangerous to people and contribute positively to the aesthetic planning of a town or city.
At present we have ~ 850 Km of high-tension (33 KV or 6 KV) underground network of various sizes distributed in entire city at a depth of 0.7-1 meter from the ground surface. The type of cables deployed are:
The data shows that, on an average,13-15 breakdowns of HT cables happen every year due to cable joint failures. Due to these breakdowns, reliability indices get affected, and also results in customer dissatisfaction.
Currently, there is no mechanism to assess the health of the cables and to predict their remaining life. Also, the exact location of the insulation weakness is not known. Carrying out Insulation Resistance test measurements for every cable does not help solve the problem as it neither reflects accurate result nor is it feasible due to shutdown issues and manpower requirements.
The main challenge here is to attain an online assessment of the cable health and to determine their useful remaining life along with the location of weak joints, without having to undertake shutdown mechanism.
Nice to have: