When deciding on the right medium voltage (MV) switchgear for your application, there are some key general aspects that should always be considered.
a) Leading factors such as line structure and protection, tripping times and selectivity, reserves/ availability, operating protocol or procedures, switchover time, in-plant generation, emergency supply or quality of power (e.g. unstable loads).
b) The selection variable (single or double busbars, bus section panel / transfer panel with switch or circuit-breaker or bus coupler unit (incl. double busbar)
When it comes to medium voltage switchgear with single busbars…
Single busbars are ideal for most supply duties. Regarding systems with a larger number of feeder circuits, it’s possible to sub-divide the busbars into sections, providing them separately with their own infeed. This would allow each section to potentially withdraw a reserve supply from a neighbouring section.
That being said, there are some notable benefits of single busbar MV switchgear.
This includes the fact that it’s totally transparent in all switching states - resulting in more easy and convenient use in the case of network failures requiring prompt solution. This in turn dramatically reduces any risk of switching faults.
Finally, in the case of fault-causing switchovers requiring carrying out, this would only necessitate the operation of circuit-breakers and nothing else. Should the incorrect circuit-breaker be accidentally operated, the safety of the switchgear will not be impacted since circuit-breakers are capable making or breaking all load / short-circuit currents under any kind of fault conditions (including earth fault).
When it comes to medium voltage switchgear with double busbars…
In some cases, double busbars should be chosen over single busbars. This includes situations where two or multiple infeeds require separate operation (e.g. if they’re from varying public utility companies), or, in cases where loads could impact power quality through flickers or voltage fluctuations, and other equipment may be sensitive to such discrepancies.
There are also cases where loads of varying importance must be distributed across busbars that are deemed either safe or more risky (such as busbars with different requirements upon availability), as well as in cases where networks require division into two sub-networks as a result of limited short-circuit strength of the equipment installed - as switchovers enable a balance of changing load current consumption.
For all things switchgear, our experts at T&T Power Group can help
Need assistance selecting the right MV switchgear for your application? (Or need a hand with anything related to powering your operations efficiently)?
That’s what we’re here for. Contact our team at T&T Power today to get started.