B08 AMD 0002_Tooele 2MW PV_01 10 10_page 20.pdf

ERCIP 2MW Solar Photovoltaic Array Tooele Army Depot, UTAH

01 10 10-20

Inverters shall be commercial off-the-shelf product, and shall be UL listed of the latest series of smart inverters. Inverter DC input voltage range shall have a lower limit of not more than half the DC system rated voltage (500V on a 1000V system, for example). Calculations shall demonstrate that PV module string voltage range relative to ambient temperature variation is optimized for the inverter(s) and fits within the inverter’s DC voltage operating range for the life of the inverter(s) (20 years). Each inverter shall have an integral customer meter. Inverters shall be adjustable and controllable to put reactive power on the grid, with VAR control range of .8 leading to .8 lagging power factor.

Both liquid-cooled or air cooled inverters shall be UL approved. Inverters shall have a minimum efficiency of 98% (CEC efficiency). Submit lab test data for COR approval. Inverters shall be in a NEMA 1 enclosure minimum, rated for indoors (refer to paragraph 4.1 for structure required to house inverters and related electrical equipment). Utility Interface to existing electrical grid shall be 12.47 kV, 3-Phase, 4-wire, 60 Hz. Refer to paragraph 4.1.A. If the existing system carries a ground neutral, then the inverter step-up transformers must have a utility interface to grid voltage of 12.47/7.2 KV. A transformer of proper voltage rating, winding configuration and capacity shall be required to match and step up inverter AC output. Inverters shall be listed by a recognized testing laboratory to Standard UL 1547 & 1741 and shall conform to all other applicable codes and standards. Inverters shall shut down the PV system during a utility grid power outage per UL standards. Inverters shall have voltage and power factor control features.

B-1. Inverters should support Low Voltage Ride Through (LVRT) Which allows the inverters to remain online for over 0.5 seconds at 0.0 volts. LVRT or an equivalent set of features to allow the inverter to continue to supply current to the grid during momentary voltage excursions. Values of 100 percent FLA at 0v for 1 second and 100% FLA at 20v for 5 seconds are typical for the PV industry.

B-2. Inverter Active, and Reactive Power Set-point/ Limitation should be able to be set and changed via a fiber optic network from an authorized third party software package. The inverter will deliver up to the set-point but no more depending upon available insolation.

B-3. Inverter Power limitation as a function of power frequency, operating on top of the Active and Reactive Set-points to reduce power output via a linear function once above a frequency set-point.

B-4. The ability to modify the default IEEE 1547 voltage and frequency disconnection values and time delays. Specifically, the values in Tables 1 and 2 of IEEE 1547 to wider and longer values for Microgrid operation.

B-5. Ability to disable the inverter's internal anti-islanding detection routine and to accept an external safety shutdown command.

B-6. Ability for the inverter to communicate, in real-time via a fiber optic network, its status, power, frequency, power factor, voltages, currents and available power from its associated battery or solar field and for this information to be brought into a third party software package for monitoring and control.

B-7. Ability to communicate using Modbus, DNP 3.0, BACnet Ethernet or other standard communication interface.

B-8. Provide a two-hour minimum dedicated UPS or ‘onboard’ UPS for all inverters.