Electrical Connection
The CHP unit’s generator (at 415 volts or 11 kilovolts, 50 Hz and three phase) must be connected to the site’s electrical distribution system at an appropriate location. This may be via a spare breaker cubicle on an existing bus-bar or a new bus-section. Where a stand-by (Island Mode) facility is required the maximum load imposed under Island Mode conditions must be within the generator’s rated capacity.
In all cases, the site’s electrical distribution system and grid in-feed must be checked to ensure that system fault levels are satisfactory and that switchgear is appropriately rated.
There are requirements to be met when connecting a generator to any part of the public electricity supply are contained in Electricity Association publication.
The power generated by a packaged CHP plant is almost always three-phase alternating current at 50 Hz, usually at 415V. Where the site electrical system at the point of connection is at a higher rating, e.g. 11kV, then an 11kV generator may be used. Alternatively, a 415V generator may be used and linked to a step-up transformer, the latter supplying electricity to the site at 11kV.
There are usually 2 modes for setting up the electrical supply connections:
