2008-08-04 - An ABB innovation has increased the performance of generator circuit breakers by more than 25 percent while simultaneously reducing the footprint, weight, noise levels and maintenance requirements of these critical power plant components.
By ABB Communications
The innovation has enabled ABB to increase the nominal current of its HECS family of generator circuit breakers (GCBs) from 18,000 amps (A) to 23,000 A, an increase of almost 28 percent.
Previously GCBs of this rating required a so-called 'forced' cooling system of pumps, fans or motors to counteract heat dissipation and keep sensitive breaker components within their rated temperature tolerances.
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| About 70 percent of the world’s GCBs are engineered and manufactured by ABB, which is launching three new GCBs with heat pipe cooling in 2008 |
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ABB has eliminated the need for these cooling devices by developing an innovative heat pipe cooling system that makes the HECS range lighter, slimmer and quieter than was previously possible.
In addition to offering a substantial increase in nominal current capability, the maintenance requirements of the new GCBs are – as with all HECS breakers - extremely low.
Nominal and short-circuit currents generate a tremendous amount of heat. The higher the nominal current, the more heat is generated. A cooling system – either natural or forced - is therefore required to keep the breaker within its temperature limit.
ABB’s HECS breakers are quieter, smaller and lighter thanks to an innovative approach based on a heat pipe cooling concept. A forced cooling system is itself a generator of heat, which in turn limits the nominal current capability of the GCB to 18,000 A, as well as creating extra weight and a larger footprint.
Natural cooling has its own engineering challenges and only becomes feasible for nominal currents above 13,000 A by increasing the dimensions, weight and footprint of the breaker components.
The success of the ABB heat pipe solution is to solve the limitations of the two existing technologies. It requires no electricity to operate and is virtually maintenance-free and silent.
Generator circuit breakers are a critical component in power plants, protecting both the generator and the power transformer. ABB has the broadest GCB portfolio on the market, covering power ratings of more than 1500 MVA and nominal currents in excess of 50,000 A.