The load bank type you need will vary depending on the applications involved. Typically load banks fall into three categories:
Resistive: The most common type, a resistive load bank provides a simulated electrical load for generators and back up power systems. They work by mimicking the operational load that a power source would handle during actual use. When used as a controlled system test, the load simulates real-life resistive loads, such as incandescent lighting and heating loads, as well as the resistive or unity power factor component of magnetic (motors, transformers) loads.
It is important to note that, In many applications, resistive loads make up a small proportion of power consumption. In data centres, for example, it is generally only heating and lighting systems which use a resistive-only load. Alongside this, other aspects of the operation incur reactive loads; these create a lagging power factor (pf), typically around 0.8, which is not accounted for when undertaking a solely resistive test.
Resistive/reactive: Resistive/reactive load banks combine both resistive and reactive elements in one load bank package, which can also be switched to enable resistive only, inductive or lagging power factor testing. This type of system can be used to test the generator set fully at 100% nameplate kVA rating.
Resistive/reactive load banks provide a picture of how well an entire system will withstand changes in load pattern while experiencing the level of power that would typically be encountered under real operational conditions. The inductive loads used in resistive/reactive testing will show how a system will cope with a voltage drop in its regulator. This is particularly important in any application which requires generators to be operated in parallel (e. larger business infrastructures such as major telecoms or data centres) where a problem with one generator could prevent other system generators from working as they should.
In addition to the main categories of loadbank listed above, DC load load banks can be used to provide an accurate load for the discharge of batteries, both following amps and voltage, from 24VDC to 700VDC, with power from 10kW to 664kW. Containerised medium voltage load banks can be used to provide higher voltages up to up to 33kV in both resistive and resistive/reactive configurations.
Tomorrow’s focus: Where will the load bank test take place?