P-Q capability diagram

A P-Q capability diagram plots an inverter's active power against its reactive power and shows the largest operating area the unit can deliver under stated operating conditions. The diagram is split into four quadrants, labelled Q1 to Q4. Manufacturers warn that the capability shown may be reduced to meet the grid code that applies in the country of installation. Vendor curves can depend on ambient temperature: one manual gives separate PVS-175 curves for operation up to 40°C and up to 30°C. These charts also mark power factor (cos phi) lines. Some manufacturers publish these charts as P-Q curves or reactive capability data for each inverter rating. Power-system textbooks describe a related idea, the circle diagram of apparent power, which plots receiving-end active and reactive power on P-Q coordinates.

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• sentence 1: support check: partial - Passages state maximum P-Q capability under specified operating conditions with P and Q axes, but the explicit definition of plotting P against Q as an operating area is only implied.
• sentence 4: review: partial - The passage has PVS-175 curves labelled up to 40°C and up to 30°C and shows cosphi lines, but it never says the temperature is ambient, and the garbled labels do not clearly show the same model has both curves. -->