The enhancement of the thermal properties of insulating oils has positively reflected
on the performance of the electrical equipment that contains these oils. Nanomaterial science
plays an influential role in enhancing the different properties of liquids, especially insulating oils.
Although a minimum oil circuit breaker (MOCB) is one of the oldest circuit breakers in the electrical
network, improving the insulating oil properties develops its performance to overcome some of its
troubles. In this paper, 66 kV MOCB is modeled by COMSOL Multiphysics software. The internal
temperature and the internally generated heat energy inside the MOCB during the making process of
its contacts are simulated at different positions of the movable contact. This simulation is introduced
for different modified insulating oils (mineral oil and synthetic ester oil) with different types of
nanoparticles at different concentrations (0.0, 0.0025, 0.005, and 0.01 wt%). From the obtained results, it
is noticed that the thermal stress on the MOCB can be reduced by the use of high thermal conductivity
insulating oils. Nano/insulating oils decrease internal temperature and generate heat energy inside
the MOCB by about 17.5%. The corresponding physical mechanisms are clarified considering the
thermophoresis effect. |
