Load bank
The device usually also includes instruments for metering, load control, and overload protection.
They are necessary adjuncts to replicate, prove, and verify the real-life demands on critical power systems.
Reactance is a circuit element's opposition to an alternating current, caused by the buildup of electric or magnetic fields in the element due to the current and is the "imaginary" component of impedance, or the resistance to AC signals at a certain frequency.
This heat must be dissipated from the load bank, either by air or by water, by forced means or convection.
With a resistive-inductive load bank, full power system testing is possible, because the provided impedance supplies currents out of phase with voltage and allows for performance evaluation of generators, voltage regulators, load tap changers, conductors, switchgear and other equipment.
Hence for a mostly inductive load this can bring the power factor closer to unity improving the quality of supply.
A combined load bank usually consists of both resistive elements and inductors that can be used to provide load testing at non-unity PF (lagging) including the capability to test the generator set fully at 100% nameplate kVA rating.
Combined load banks incorporate resistors and inductors all in a single construction which can be independently switched to allow resistive only, inductive only, or varying lagging power factor testing.
It’s worth noting that combined load banks can consist of resistive, inductive, and capacitive (RLC) also.
The ideal solution is a combination of both resistive and reactive elements in one load bank package.
Many backup generators and turbines need to be commissioned at nameplate capacity using a combination of resistive and reactive load to fully qualify their operating capability.
The resistive/reactive combination load banks are used to test the engine generator set at its rated power factor.
