Improvements have been made by Outram Research to one of the company’s analysers, which now features an enhanced ‘Interharmonics’ option. The company advises this makes it one of the first power quality analysers to record simultaneously all harmonics up to the 100th, on all three phases and the neutral, on either current or voltage.
As a result engineers can quickly analyse and then eliminate power quality problems found due to high-frequency harmonics generated by uninterruptable power supplies (UPSs), drives or inverters.
The company advises by simultaneously recording all current or voltage harmonics to the 100th and many other electrical parameters, the PM7000I can reduce testing time, pinpointing potentially problematic higher-order harmonics; removing the need for a trial and error approach. For a 3-phase 4 wire wye configuration, the General Parameters function records over 70 power quality parameters in addition to the 400 streams of harmonic data. Users can also choose one of thirteen different averaging intervals, from one second to two hours.
These devices are said to offer 32 detailed recording channels using the company’s Single Cycle Adaptive Store that records power quality parameters such as voltage, current (including inrush current), harmonics, flicker, unbalance and power factor down to a single cycle without the need to set triggers or levels. In this device these channels can also be used to extend harmonic recordings up to the 127th order.
Because legislation focusses on lower frequencies, manufacturers often concentrate on reducing the presence of the first 50 harmonics,” said John Outram, Managing Director of Outram Research. “However, users of drives, UPSs or inverters, such as data centres, power critical manufacturing facilities and solar power plants, may be affected by higher-order harmonics generated by these machines. These harmonics therefore need to be monitored and controlled to avoid problems such as overheating machinery or premature equipment replacement.”
Another concern is that higher-order harmonics, created by renewable generation connected at the transmission level, may be emerging on the HV networks. These can then percolate right down to the end user so need to be managed.”