6.6kV Breaker with in-panel rating of 3000A

[RRaghunath]

We are looking for indoor metal clad switchgear for a power plant. The requirement is the incomer shall have 3000A in-panel rating at a reference ambient of 50degC.

I know VCBs and SF6 CBs are available with 3150A rating but at 40degC (IEC reference temperature).

One estimate is the 3150A breaker at 50degC ambient and with IEC temperature rises (with silver plated joints) can only have 2400A in-panel rating.

I am aware we can have the required rating in GIS range, but it is expensive and do not want to consider at this stage.

Appreciate any help. Thanks in anticipation.

 

[cuky2000]

Even though ANSI/IEEE Std. Maximum published continuous rating are for 3000A at 40oC, there is available in the market MV switchgears tested for 4,000 Amp or higher.
Other possibility is to use 2-3000 circuit breakers in parallel for a rated capacity around 5000 Amp. Some manufacturer could offer 3750 Amp up rated switchgear with fan-cooled assistance.
Beware that the physical size of the switchgear cubicle and busbars may be increased to meet the requirement.

 

[DrSpark]

I am sure you must have already given this a thought but I will go ahead and mention it..

It would seem to me that a standard GIS solution suitable for 50 deg C would still be cheaper than a customized or derated version of Air or Vaccum Insulated gear.

But if you must then I have worked with Toshiba's 4000A 7.2kV breakers. But I would still try and go for a GIS with Vaccum breakers from Areva (Alstom) or Siemens. The other option would be to go for GIS with SF6 breakers from Schnieder. All of them have a special product lines and applications for FPSOs and Middle Eastern Countries where the average ambient temp. are rated upto 50 deg C. ABBs ZX2 is also a good technology with their tubular busbars and spring joints.

Hope it helps.