Preliminary study of a relay transmitted cooling system with heat pipes and LHP system in large capacity gas insulated transformers

The growing rated capacity of gas insulated transformers (GIT) are confined by the limitation of cooling capability. Hence a new thermal relay transmitted cooling system was applied in GIT and presented in this paper. The whole cooling system consists of conventional heat pipes and loop heat pipe (LHP): Dozens of non-metallic conventional heat pipes are distributed in the windings, absorbing heat and transmitting it to the LHP cooling system which is attached to the upper part of the conventional heat pipes. Then the LHP system brings heat out of the transformer and dissipates it to circumstance by boiling and condensing circulation of the fluorocarbon liquid in the LHP system. This relay transmitted cooling system is self-circulated, needing no additional blowers or fans installed in transformers. An experimental model is designed, fabricated and tested, and the testing results demonstrated that it could improve the cooling capability of GIT greatly, and has the feasibility to develop GIT of larger capacity.