Static Var Generator (SVG) Private6 days ago - Real estate - Battambang - 12 views
The principle of the SVG static var generator is very similar to that of Active Power Filter, as demonstrated in the picture below. When the load is generating inductive or capacitive current, it makes load current lagging or leading the voltage. SVG detects the phase angle difference and generates leading or lagging current into the grid, making the phase angle of current almost the same as that of voltage on the transformer side, which means fundamental power factor is unit.
Delta’s PQC series SVG is also capable of correcting load imbalance.
Delta PQC Series SVG static var generator is also modular in design, and the Delta SVG system consists of one or several SVG modules and an optional Liquid Crystal Monitor & Control Panel (LCM). Each SVG module is an independent reactive power compensation system, and users can change the SVG rating by adding or removing SVG modules.
SVG modules and LCM panel can be embedded in Delta’s standard SVG cabinet or in a customized cabinet. There are usually breakers, cable terminals and Surge Protection Device (SPD) in the SVG cabinet.
Active harmonic filters are more of a system solution. How do they work?
Harmonics come from the nonlinear load. Active harmonic filter, also called harmonic correction units, is parallel devices that act like a noise cancellation system and inject equal and opposite frequencies to mitigate harmonics. The filters can also provide additional current to correct the power factor. So, what’s left coming from the source flowing back to the utility is only a nice, clean current that is in phase.
For example, if we run four 6-pulse variable frequency drives at the same time, we have a harmonic spectrum of 5th and 7th and 11th and 13th harmonics. The waveform will show a significant amount of harmonic current in the total harmonic distortion. When the active harmonic filter is turned on, it will inject equal and opposite harmonics to cancel what’s there. The waveform now will be clean and in phase. If we go back and look at the harmonic spectrum, the current distortion is very low.
Active harmonic filters can effectively cancel harmonic distortions from the network. This blog post will explain the key criteria that should be kept in mind when buying an active harmonic filter.
1.1. Inverter topology
Interharmonics are usually caused by synchronization issues. If the installation includes interharmonic sources, the manufacturer should be consulted as not all AHFs can deal with this. It is a common issue with cycloconverters or some types of older wind turbine generators.
1.5. Harmonic compensation capacity
AHFs are offered in a range of voltages, most common is 200V up to 690V. Some manufacturers can produce AHFs for higher voltages, up to 1000V, without step-up transformer, reducing costs and footprint. It is possible to connect AHFs to high voltage (over 1kV) systems using a suitable step-up transformer. Step-up (or step-down) transformers can reduce compensation performance due to increased impedance between the AHF and network.