THE widespread use of variable frequency drives has made the imposition of harmonic distortion limits at the point of common coupling (pcc) which for many industrial and commercial installations is the metering point, necessary.
Despite their efficiency, drives cause harmonic distortion in the power system and this is particularly true of the ubiquitous 6-pulse variable speed systems.
Tight limits of one third of the maximums called for by AS2279 are frequently required at the point of common coupling by power distribution companies and authorities.
In practice therefore total harmonic voltage distortion must be less than 1.67%, odd harmonics less than 1.33%, and even harmonics less than 0.67%.
Obviously the impedance of the external supply system is important in determining the degree of voltage distortion but in practice the consumer's harmonic current distortion must be kept around 5% and Matrix D Series filters are ideal in this situation.
Having established that minimising harmonics in the consumer's power circuits is necessary it is found only too frequently that retrofitting filters is an impossible task because of their size.
There simply isn't enough space in existing switchboards or MCC's to fit them. Sometimes there are also cost factors that make retrofitting compare marginally with the cost involved in living with a high level of current distortion.
Available from Westek Electronics , the new MTE MATRIX D series harmonic filters cut through these obstacles by providing a series of high performance filters that are not only significantly smaller in volumetric size but also have considerable savings in weight through novel magnetic circuit design which in turn helps to reduce their cost.
The MTE Series MATRIX D harmonic filters will cut heat dissipation in cables, busbars and switchboards--and reduce load on substation transformers as well as provide superior dynamic performance which is of great importance in plant with variably loaded electronic drives.
The use of MATRIX D series filters also find application in dealing with massive line transients such as occurred in the case of 400kW drives for a series of mine dewatering pumps.
The MTE MATRIX now offers the very latest in harmonic filtering developments: the D series Harmonic Mitigating Reactor with a common core-based filter.
The MTE MATRIX D series with its patented unitary magnetic circuit topology represents a significant refinement over the series B while having the same excellent reliability profile.
The advantages of the new MTE MATRIX technology are very significant:
* Up to two-thirds of filter space saving.
* Smaller capacitors.
* Designed to outperform 18-pulse converter stages for variable speed drive dc-links. The MTE MATRIX D series reduces harmonic content in current to as little as 5%.
* Represents a 40% reduction over the harmonic level from many other commercially available filters.
The MTE Series MATRIX D is available as 415 and 690 volt filters with line current rating from 6 amps to 786 amps. Current ratings can be increased by paralleling filters.