HV Breaker Hydraulic vs Pneumatics
HV Breaker Hydraulic vs Pneumatics
(OP)
We came across an application with HV breakers with some of them specified with hydraulic mechanism and others specified with pneumatic operating mechanism.
Although both units have some pricing and physical differentials, the electrical performance is pretty much similar.
Doe any one know why to specify two breakers design in the same facility?
Although both units have some pricing and physical differentials, the electrical performance is pretty much similar.
Doe any one know why to specify two breakers design in the same facility?






RE: HV Breaker Hydraulic vs Pneumatics
I've experienced much less trouble with mechanical spring (typically torsion bar springs in the higher voltages) driven breakers.
RE: HV Breaker Hydraulic vs Pneumatics
With the disappearance of oil circuit breakers, per unit maintenance costs have gone down on HV breakers and most calls concerning them are related to the pneumatic or hydraulic mechanisms.
As for the question "Doe any one know why to specify two breakers design in the same facility?", I'm thinking that vendor ! has offered a really nice round of golf, and Vendor 2 has indicated multiple free meals.
But then I'm considered cynical...
old field guy
RE: HV Breaker Hydraulic vs Pneumatics
The breakers in question were ABB's ELK series from the Swiss part of the empire and were generally a delight to work on, other than the KKS numbering system used to defeat me because I didn't use it frequently enough to stay conversant!
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If we learn from our mistakes I'm getting a great education!
RE: HV Breaker Hydraulic vs Pneumatics
The interesting part is both units (hydraulic and pneumatic) were supplied by the same vendor.
The substation is in breaker 11/2 configuration designed for 50 kA using breakers rated for 63 kA independent pole operation (IPO). There are two single shunt capacitor banks and two shunt reactors mechanically switched by dedicated circuit breakers.
I tried to find the rational with some of the utility engineers involved on this design and also with the vendor of the circuit breaker. However, I was not lucky finding a good answer to justify using one vs. the other type of breaker. Appear that the engineers that developed the guideline are not longer with the utility and not ones know the background or rational of this application.
I am posting a list of rated parameters for both breakers with the hope that some one brings some light or suggestion to demystify why both units are used in the same substation.
RE: HV Breaker Hydraulic vs Pneumatics
RE: HV Breaker Hydraulic vs Pneumatics
The torsional bars operating mechanism do not meet the CO duty cycle required by the utility project and the utility standard practice. The selection of this vendor was based in several factors including the high TRV rating (above the Std values by IEEE/IEC) driven by a few HV series cap banks connected in the power systems.
RE: HV Breaker Hydraulic vs Pneumatics