Uninterruptible Power Supplies and Harmonics

Harmonic pollution is an increasing problem in Europe that designers of power continuity programs and manufacturers regarding UPS (uninterruptible power supplies) cannot ignore. Typical harmonic problems include the distortion connected with mains power supply voltage, overheating of wiring, neutral conductors, supply transformers and switchgear, and nuisance tripping connected with breakers. Harmonics can also disrupt equipment within the same supply and lead to random failures. The Best Guide to find waterproof led power supply.

Harmonics are caused by discord or current waveforms having frequencies multiples with the fundamental frequency – with Europe, 50Hz (50 rounds per second). The many are always ordered in a distinct sequence: the 2nd harmonic is 100Hz (2x50Hz), your third 150Hz and the fourth 200Hz, and so on.

The particular problem is connected with Triplen’s (third order) harmonics. Harmonics is a challenge for power continuity management due to many switch-style power supply (SMPS) loads staying connected to modern electrical circulation networks – and their affiliated UPS systems. These are the commonest form of power supply unit (PSU) in use today. However, as a nonlinear load, they draw all their power in regular controlled pulses of current originating from a mains power supply rather than a continuous linear supply. This tends to lead to SMPSs generating substantial harmonics, especially when many people are supplied from a sole three-phase mains power supply.

Specifically, system designers must be aware of the potentially damaging Triple-Ns (or Triplens) whose harmonic buy numbers are multiples regarding three and include the well-known third-harmonics as well as ninths and fifteenths. Thirds are probably among the most challenging harmonic regarding fairly neutral conductor loading within a three-phase system. Whereas other harmonics cancel each other out, third-harmonics are in phase with each other and exhibit a summing result which greatly increases the existing – potentially overloading conductors and switchgear.

Harmonics and also total power factor: implications for UPS dimensions. Harmonics are also closely relevant to power factor management, another key facet of uninterruptible power supply system design, style, and implementation. The shift power factor is only appropriate to the fundamental frequency (50Hz in Europe). It, therefore, would not consider the power factor produced by any harmonics evoked into the mains power supply from the load itself (referred to as the distortion power aspect and produced by the harmonics produced by nonlinear loads). The particular combination of the displacement strength factor and the distortion electric power factor gives what is known to help UPS systems experts as being the true power factor. If correctly sizing a HIGHS, an understanding of this is critical.

Minimization of total harmonics daub. Harmonics issues must be dealt with at the design stage regarding any power continuity program, not least because individuals are responsible for the harmonic ranges introduced into their three-phase mains adapter supply.

A UPS can be fitted with a harmonic filtration (post-installation), but this is always a costly and inelegant option as extensive internal cabling changes may be required. To get a transformer-based UPS, using a 12-pulse rectifier in place of a 6-pulse set will reduce the degrees of THDi (total harmonic distortion). Coupling this with an innate filter will lower it to around 4%.

For a transformerless uninterruptible power supply, THDi degrees of less than 4% can be achieved simply by installing an active harmonic filtration. However, levels as low as 3% can now be achieved by several designs whose rectifiers are usually IGBT (Insulated Gate Bipolar Transistor) based. This can eliminate the need for an additional active harmonic filter and simplify the particular UPS design process. These designs are expected to become standard: They reduce initial fees and allow a smaller HIGHS system footprint while raising input power factors.

Dynamic harmonic filters reduce the effects of leading power components. When designing a power continuity approach and UPS system, a variety of methods can be applied to can help the impact of leading electric power factors (where the current waveform leads the voltage waveform): ensuring that leading power components represent a smaller percentage with the UPS load, installing electric power factor correction between the HIGHS and the load, increasing HIGHS size (and that of almost any standby generation capacity) in addition to specifying a UPS is having leading power factor functionality.

A popular approach to reducing the result of leading power factors for a UPS installation is to use the earth’s most active harmonic filter with electric power factor correction on the HIGHS output. Unfortunately, this often presents UPS with a more creamy load but results in bigger capital and installation prices, lower efficiency, and a more significant footprint.

Familiar territory to get UPS manufacturers. Although many components of harmonics must be considered if specifying a UPS process, reassurance can be gained from the fact that this is a familiar area for UPS manufacturers like Riello UPS. End users and professional advisers can certainly be assured that this technical aspect of the HIGHS application will be thoroughly dealt with during the modern consultative revenue and specification process.

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