Volt-watt power derating

Volt-watt derating is an open-loop limit on real power that responds when the grid voltage goes too high. Grid voltage is measured at the point of interconnection meter. A programmable curve sets how far output is limited as the voltage rises. The derating takes effect over a set open-loop response time, which defaults to 10 seconds under IEEE1547-2018 and 5 seconds under Rule21. In the Tesla controls, the first real power limit is fixed at 1 per unit. A read-only register reports the power limit worked out from the Volt-Watt curve, so trend that register alongside grid voltage. On Solis inverters Volt-watt is one of several working modes and can run together with Volt-var. The working mode display shows which of the two takes priority.

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• sentence 4: support check: partial - Real power limit 1 fixed at 1 pu and the read-only Volt-Watt Real Maximum register are stated, but the advice to trend it alongside grid voltage is not in the passages. -->