IIT-Madras develops efficient technique for identifying pollution deposit level in power transmission network

Chennai : Researchers at the Indian Institute of Technology-Madras
(IIT-M) have developed an efficient technique for identification of pollution deposit
level in power transmission network.
The pollution-related electrical flashover occurs in the working conditions and can
lead to blackouts and collapse of the system.
Cleaning the polluted insulator under the working condition, while technically quite
challenging, seems to be the fool-proof way of resolving the problem.
The IIT-Madras Research Team is planning to approach NTPC, Power Grid and other
utilities to demonstrate this technology and its use in the real power system network,
a release from IIT-M said today.
In non-technical terms, the key applications and benefits of this research included,
online monitoring without interrupting power supply, rapid and remote measurement,
non-invasive/non-destructive measurement and the most economical process.
The reliability of an electric power system largely depends on the performance
of the electrical insulation. The outdoor insulation on the transmission lines
running over a few lakh kms and the substation equipment, in addition to the
electrical, thermal and mechanical stresses, are subjected to environmental
pollution.
However, due to the high operating voltages and huge spatial span of the electrical
transmission system, it would be essential to ascertain the level of pollution
deposition and the type of pollutant before such a mammoth exercise can be planned.
For substations and lines running close to the chemical plants, the deposit can
involve NaCl, Al2O3, C, SiO2, CaSO4, and KNO3, among others, while that close
to the mining areas can acquire Nickel, Copper, and Manganese, besides a few
other materials, the release said.
It would be much simpler and economical to measure the contents and thickness of
the deposition remotely (non-invasively).
An elegant solution based on Laser Induced Breakdown Spectroscopy (LIBS) has been
developed by research groups of Prof.R.Sarathi, Department of Electrical Engineering,
IIT Madras, and Prof. N.J. Vasa, Department of Engineering Design, IIT Madras.
The initial results of the study have been published in reputed peer-reviewed journal
IOP- Measurement Science and Technology.
At present, by shining a laser beam at a distance of 40 metres, the researchers can
identify the constituents of pollution deposition, while efforts are underway to extend
this distance to 100 m.
This would enable assessing the pollution layer on transmission line insulators and
the windmills either from the ground or from a drone.
This work was financially supported under the National Perspective Plan of the Union
Ministry of Power through Central Power Research Institute (CPRI), Bengaluru.
Prof. Sarathi said “the presence of salt and other pollutant deposits on the insulating
materials were successfully identified using the LIBS analysis. The level of pollution
on the insulating material was identified by using the proposed linear relationship
between normalized intensity ratio of the LIBS spectra and the equivalent salt deposition
density (ESDD) level.”
“The artificial neural network (ANN) assisted LIBS technique is successful with high
classification accuracy (more than 99 per cent), in the classification of the polluted
insulating materials based on the ESDD level and type of pollution.”