An important consideration for a generator circuit breaker is its current - carrying capacity. The rated currents of generators typically span from 3000 A (for 50 MVA units) to 50000 A (for 2000 MVA units). As these currents flow through the circuit breaker, heat is generated. To increase the rated current of a specific circuit breaker, it is essential to enhance the heat transfer to the surrounding environment, ensuring that the temperatures of all components remain within acceptable limits.
Consequently, the key challenge lies in effectively removing this heat from the conductor. Heat pipes are highly efficient heat - transfer devices. They consist of a hermetically sealed container filled with a small quantity of working fluid. In theory, a heat pipe can function across a wide temperature range, from the melting point to the critical temperature of the working fluid. Heat pipes operate by utilizing the evaporation of an appropriate working fluid, transferring the latent heat, and then condensing the vapor back to a liquid state.
Currently, ABB's generator circuit breakers (GCBs) with high - current ratings are leveraging this technology to manage heat dissipation more effectively.
