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Supply Distortion by drive


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#1 marke

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Posted 13 May 2002 - 09:37 AM

I am involved in an existing installation with a large pump that shares a supply transformer with two consumers houses. The inverter is a significant load and well exceeds the combined loads of the houses. The transformer is fed by a long overhead 11KV line.

When the pump is running, one house has problems with the harmonics generated by the VFD but the other does not. Both houses are fed directly from the transformer terminals with underground cables.
The inverter is fitted with DC Bus chokes and also with a coupled three phase inductor on the input.
The inverter is rated at about 70% of the transformer rating.
One solution to the problem is to install a second transformer to supply the two houses but that is an expensive option. Is there a cheaper and effective option that is guaranteed to work??

#2 Tractor

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Posted 06 January 2010 - 04:27 PM

QUOTE (marke @ May 13 2002, 09:37 AM) <{POST_SNAPBACK}>
I am involved in an existing installation with a large pump that shares a supply transformer with two consumers houses. The inverter is a significant load and well exceeds the combined loads of the houses. The transformer is fed by a long overhead 11KV line.

When the pump is running, one house has problems with the harmonics generated by the VFD but the other does not. Both houses are fed directly from the transformer terminals with underground cables.
The inverter is fitted with DC Bus chokes and also with a coupled three phase inductor on the input.
The inverter is rated at about 70% of the transformer rating.
One solution to the problem is to install a second transformer to supply the two houses but that is an expensive option. Is there a cheaper and effective option that is guaranteed to work??


#3 Davemell0

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Posted 13 February 2010 - 08:55 PM

QUOTE (marke @ May 13 2002, 10:37 AM) <{POST_SNAPBACK}>
I am involved in an existing installation with a large pump that shares a supply transformer with two consumers houses. The inverter is a significant load and well exceeds the combined loads of the houses. The transformer is fed by a long overhead 11KV line.

When the pump is running, one house has problems with the harmonics generated by the VFD but the other does not. Both houses are fed directly from the transformer terminals with underground cables.
The inverter is fitted with DC Bus chokes and also with a coupled three phase inductor on the input.
The inverter is rated at about 70% of the transformer rating.
One solution to the problem is to install a second transformer to supply the two houses but that is an expensive option. Is there a cheaper and effective option that is guaranteed to work??


Marke

If you talk to someone like MTE corporation they may be able to help you guys out. A six pulse drive can be quite noisy even with a DC bus choke and input reactor. So I think your two options are to install a new transformer, or to install a harmonic filter. The harmonic filter should work fine, but I do not know how its cost will compare to the transformer. This is not meant as a promotion of MTE, they are just an example of a potential source for harmonic filters. Also since you have dc bus chokes and an input reactor I am assuming this is a low voltage drive, if it is a medium voltage drive you will have to purchase a custom harmonic filter for your exact application.

Thanks


Dave

#4 PowerQualityDoctor

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Posted 14 February 2010 - 06:32 PM

What are the affects on the house? You cannot "kill" all the harmonics (even with active filters), but can reduce their affect.

You can also try to change the switching frequency. It can change the amount of distortion, but more important can change the results as sometimes specific frequency creates a resonance.


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#5 jOmega

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Posted 11 March 2010 - 05:17 AM

QUOTE (PowerQualityDoctor @ Feb 14 2010, 12:32 PM) <{POST_SNAPBACK}>
What are the affects on the house? You cannot "kill" all the harmonics (even with active filters), but can reduce their affect.

You can also try to change the switching frequency. It can change the amount of distortion, but more important can change the results as sometimes specific frequency creates a resonance.




Au Contraire. Neither assertion is correct.






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