The point of interconnection (POI), often called the point of common coupling (PCC), is where a customer's local electric power system connects to the utility's area electric power system. It is the point on the utility grid that other customers are connected to, or could be connected to. In most cases the PCC matches the service point as defined in the NEC and the NESC. It is different from the point of DER connection, which is where the DER unit itself connects inside the local system. Grid connection rules say whether a requirement applies at the point of interconnection or at the inverter terminals, and the grid operator or local regulations choose which reference point to use. Inverters often have settings tied to this point, such as a Voltage PCC Set value required under Rule 21, or the nominal apparent power at the PCC. Large plants also use the POI for metering and for grid strength checks: a revenue busway meter may be required at the POI, and inverter limits are given in terms of short-circuit ratio at the POI. Under the NEC, each interactive system's point of interconnection with other sources must be labeled at the disconnecting means. Examples include AC combining panels, AC disconnects and backfed breakers.
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related_toc1 drafted · lead Point of common coupling proposed
SMA glossaries define PCC as the point of interconnection on the utility grid that other customers are or could be connected to.
tbl=16.r12 h=86f28a2fdf58tbl=52.r1 h=c47274b301a2tbl=138.r1 h=e2f9fbaac88ac2 verified · fact Area electric power system
The PCC is where a Local EPS connects to the Area EPS.
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c3 verified · fact Local electric power system proposed
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c4 drafted · lead Reference point of applicability proposed
Grid connection requirements may apply at the point of interconnection or at the inverter terminals; the grid operator or local regulations decide which.
tbl=67.r1 h=17b46bbe5322sec=3.1.1 h=966ed9478873sec=3.1.1 h=5183f1d450b3c5 drafted · lead Short-circuit ratio
Inverter configuration limits for weak grids are given in terms of the SCR at the POI.
tbl=3.r1 h=4ad59069af20tbl=4.r1 h=3cdd438fcc23tbl=5.r1 h=9bc470babdfatbl=6.r7 h=51d38b6fdf9breview note: support check: partial - Passages show SCR values at the POI for inverter configurations, but do not clearly state weak-grid limits; the tables are fragmentary.; review: partial - The table rows tie SCR values at the POI to inverter configurations, but no quoted passage says these are configuration limits or that they apply to weak grids.
c6 verified · fact Energy meter
For Tesla Utility Hybrid systems, one busway meter at the point of interconnection is required.
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An island is energized by Local EPSs through their associated PCCs.
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