Distributed Generator Paralleling Device

[Kiribanda]

Gentlemen,

This question is about the Distributed generation by Independent Power Producers.

Clause 4.1.8.3 under the heading Paralleling Device of the relevant IEEE Standard 1547-2003 says that the “Interconnection System Paralleling Device shall be capable of withstanding 220% of the interconnection system rated voltage”.

If I am not mistaken this paralleling device is the HV circuit breaker of which the IPP generator is synchronized to the Utility. Does this mean that the out of phase switching voltage is 220 % of the system voltage? IEEE standard for HV circuit breakers (IEEE Std. C37.04) defines a different voltage for out-of phase switching current.

What is this 220 % requirement?

Could our learned members throw some light on this?

Thanks in advance!

Kiribanda

 

[davidbeach]

The 220% requirement is for voltage across the open contacts, not an anticipated closing voltage difference. If both sources are 10% above nominal (maximum permitted by other standards) and 180 degrees out of phase, the total voltage across the open contacts will be 220% of nominal voltage.

 

[dpc]

rms.

 

[polyphase]

Well said, Davidbeach and dpc. That is a complete and concise answer.

 

[Kiribanda]

Hello,

I believe I got the answer.

Thanks everybody for your valuable inputs.

Kiribanda