[UKB from CANADA]

500MW power station under erection. Generator Transformer comes in separate phase banks.

Problem:

As per design the vector group is Yd11 but on site Yd5 has arrived.

The LV side delta is made by Generator Bus Duct connections.

Solution:

1) Change Bus Duct connection. ( Much delay in commissioning activities)

2) Modifications done in protection circuits of Generator,GT,UAT. to accommodate this change groups.

Question:

Is it possible ? I need some more details as to how things were done.

Thanks

Topic

[Hamid]

In new numerical differential relays, vector group modifications are done easily. Therefore they hadn’t some problem with protection system. In regard to different vector group step up transformers possibility, if there are not any interconnection path between two power generators via unit transformers and relevant auxiliary switchgears, it is not problem; because we can have two or more generators with asynchrony voltage system that are connected to common bus by different group transformers.

[Author]

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