Harmonic prediction at planning stage
Harmonic prediction at planning stage
(OP)
Evening all. The new G5/4 regulation requires new (and possibly existing?) plant to comply within harmonic limits. At the design stage, you are required to forecast the harmonic levels the plant will generate. Now there seem to be a couple of companies offering to do this for you (at a tidy price) so I’m wondering does anyone on here know the main principles for doing it ‘in-house’?
Many thanks.
Many thanks.






RE: Harmonic prediction at planning stage
RE: Harmonic prediction at planning stage
RE: Harmonic prediction at planning stage
G5/4 is the UK specification governing the harmonics allowable on a utiloy network. Its often misused as it only refers to PCC (Point of common coupling) which will be the clients site incomer maybe at 11kV or 132kV. However, somewhere within the site on an LV board the harmonics could be shocking and causing problems with other equipment.
I am not familiar with IEEE519.
RE: Harmonic prediction at planning stage
Some companies selling harmonic mitigation equipment and services have white papers posted on their web sites.
Some print and online trade magazines have articles available online. See: http://www.drivesurvey.com/index_library.cfm
http://www.drivesurvey.com/index_market.html
RE: Harmonic prediction at planning stage
Follow the link: http://www.gambica.org.uk/ and click on "Publications". The document is "GAMBICA Guide to Energy Networks Association Recommendation G5/4-1, Third Edition"
To answer your question mark; yes, it can apply to existing equipment, if it is out of limits but somebody would have to complain to the Network Operator first for it to get that far.
There are a number of simulation tools that allow predictions of harmonics generated by certain products but if you have a substantial investment going on that involves the installation on non-linear loads, it is advisable to carry out measurments at your PCC (point of Common Coupling). This is not usually cheap but if you get the right company doing it, the recommendations they would make should pay for that particular investment.
RE: Harmonic prediction at planning stage
You need to consider several things
1) The size and nature of the loads you are connecting to the network (preferably using manufacturers data)
2) The Power system configuration (zero sequence paths may be avoided)
3) System impedance plays a part, the higher your system fault level is the higher the impedance will be and the more the harmonic problems you will have.
Look at the power system from the bus (or buses concerned) and reduce the network to a Thevenin equivalent.
RE: Harmonic prediction at planning stage
----------------------------------
I don't suffer from insanity. I enjoy it...
RE: Harmonic prediction at planning stage
RE: Harmonic prediction at planning stage
RE: Harmonic prediction at planning stage
I had meant to say lower fault level