Harmonic by inverters in large plant/phase shift transformer plan

Dear All,

We are engaged in the design of a large plant. Problem is 5th harmonic due to 6-pulse rectifier contributed from inverter/VFD, which result in 23% THDi (Siemens and Danfoss software evaluated data)

1) There are hundreds of inverters each rated around 380V/10kW. during their operation, they will be quite stable in terms of load percentage; so we attempt to group them into two balanced halves with each one tied to a winding of a phase shift transformer (rated around 2000kVA, with two secondary windings, one delta and one Wye as a try to get 30 degree shift).

2) With this configuration, we thought 80% of 5th harmonic from inverter loads could be cancelled.

3) we called some experts of our suppliers with support experience here in China; however, most of they cannot give us an estimation for how much is the reduction effect will be. They will usually propose us LV filtering capacitor bank, which our client is with much concern in.

Did any one in the harmonic world could feed us some idea or even had similar devil killed. Please give us help, thanks very much !

Alex Feb 26, 2008

Reply to
wangxuegu
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On 2=D4=C226=C8=D5, =CF=C2=CE=E76=CA=B145=B7=D6, snipped-for-privacy@hotmail.com wrote= :

anyone could give a hint here ? thx

Reply to
wangxuegu

On 2=D4=C226=C8=D5, =CF=C2=CE=E76=CA=B145=B7=D6, snipped-for-privacy@hotmail.com wrote= :

Is there anyone in the special field ?

Reply to
wangxuegu

You could try

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and forum "Electric motors & motor controls engineering"

Reply to
NotMe

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