Date: Mon Jan 04 2021 13:23:28 GMT-0800 (Pacific Standard Time)
CPUC Decision 14-12-035 December 18, 2014 - requires smart inverters be used with solar installations
The Decision recognizes that today’s “smart inverters” have many capabilities, including:
- The delivery of DC power into an AC system, such as photovoltaic power to the AC grid; and the delivery of AC power to a DC load, as in charging a battery from the grid.
- The generation or absorption of reactive power so as to raise or lower the voltage at its terminals.
- Delivery of power in four quadrants, that is, positive real power and positive reactive power; positive real power and negative reactive power; negative real power and negative reactive power; and negative real power and positive reactive power.
- The detection of voltage and frequency at its terminals and the ability to react autonomously to mitigate abnormal conditions: to provide reactive power if the voltage is low; to increase real power output if the frequency is low.
- In combination with a communication link, to deliver real and reactive power and to charge and discharge storage facilities in accordance with signals from the utility.
The Decision sets a timeline under which solar installations California's must use advanced ("smart") inverters. Namely
12 months after the date the Supplement SA of UL-1741 (with CA requirements) is approved by the full UL-1741 Standards Technical Panel.
UL-1741 is the existing standard for inverters used to connect solar power systems to the electricity grid. The existing standard covers older types of inverters that have little on-board smarts. Supplement A adds requirements for those inverters with on-board smarts.
The Decision discusses further requirements in these areas:
- Anti-Islanding Protection: Revise Electric Tariff Rule 21, Section H.1.a.(2) to reflect proposed new voltage ride-through settings;
- Low and High Voltage Ride-Through: Revise Electric Tariff Rule 21, Section H.1.a.(2) and Table H.1 to reflect proposed new default voltage ride-through requirements;
- Low and High Frequency Ride-Through: Revise Electric Tariff Rule 21, Section H.1.a.(2) and R21 Table H.2 to reflect proposed new frequency ride-through settings;
- Dynamic Volt-Var Operation: Revise Electric Tariff Rule 21, Sections H.2.a, H.2.b, H.2.i and R21 table H.1 to reflect proposed new dynamic volt/var operations requirements;
- Ramp Rates: Add new Electric Tariff Rule 21 sub-section within Electric Tariff Rule 21, Section H to include proposed new ramp rate requirements;
- Fixed Power Factor: Revise Electric Tariff Rule 21, Section H.2.i to reflect the proposed new fixed power factor requirements; and
- Soft Start Reconnection: Revise Electric Tariff Rule 21, Section H.1.a.(2) to reflect proposed new reconnection by soft-start methods.