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Date: Fri Mar 30 2018 18:03:23 GMT-0700 (Pacific Daylight 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:

  1. Anti-Islanding Protection: Revise Electric Tariff Rule 21, Section H.1.a.(2) to reflect proposed new voltage ride-through settings;
  2. 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;
  3. 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;
  4. 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;
  5. Ramp Rates: Add new Electric Tariff Rule 21 sub-section within Electric Tariff Rule 21, Section H to include proposed new ramp rate requirements;
  6. Fixed Power Factor: Revise Electric Tariff Rule 21, Section H.2.i to reflect the proposed new fixed power factor requirements; and
  7. Soft Start Reconnection: Revise Electric Tariff Rule 21, Section H.1.a.(2) to reflect proposed new reconnection by soft-start methods.
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