Connecting transformer to genset

A

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Anonymous

i have transformer 2500 kva brand crosstech with specification:
primary side -
voltage: 4100
ampere: 347

secondary -
voltage: 480/227
ampere: 3007
vector: Dyn11

I want to connect with generator set 2 x 1500 kVA.

first, i have synchronize the genset. and then i want to supply to the transformer. when i turn on the acb to the transformer, the acb is tripping. what's wrong about my transformer or my genset??? what is term and condition to parallel the genset and the transformer??

best regards,
m_umar_r
 
S

Shailesh C Patel

there are several ways of ACB tripping like over current, phase failure, phase reverse, ground faults, phase unbalance, pls mention it. have u charge transformer with no load, i mean with open secondary of transformer?

Regards,
Shailesh C Patel
FDC - Control Systems And Instrumentation
Reliance Engineering Associates(P) Ltd.
 
M
The generator neutral is probably solidly grounded, so is the LV side of the transformers. When they are connected together, some low level of current will flow, and is detected as a ground fault. A possible solution is to disconnect the ground on the wye of the transformers, leaving the only system ground on the generator neutral.
 
Responding to Mike Bailey's Fri, Sep 23, 10:51pm comment... current flow between primary and secondary ground connectons is not the case:

When an ungrounded primary of a transformer is supplied from a grounded source, and a ground-fault exists on the transformer secondary, then, there is no current flow in the source's ground connection. However, two phases of the supply will "see" 57.7% [sqrt(3)/3] of the current that would flow for a secondary ground-fault.

The above can be confirmed by inspection. Two poles of the primary ACB will exhibit burn marks. The 3rd pole will be "clean!"

The 57.7% value will be constant even if the primary source is intentionally grounded via a current limiting resistor or impedance.

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])
 
It is better to remove one solid ground(better transformer side)and to protect transformer we can put a CBCT triggered Earth fault relay.

I think it is better syncronize the DG set,after charging the transformer with one dg set.

Rajan
 
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