Project Description
This design-build project provides an exterior photovoltaic (PV) array electrical system consisting of civil, site utilities, high voltage electrical generation equipment, wiring, conduits and grounding, and includes all accessories and devices necessary and required for a complete a usable solar powered generating system. The PV System has a peak AC power total output capacity of 700KW PV.
The solar array’s Photovoltaic Modules consist of monocrystalline (mono) silicon photovoltaic modules, ground-mounted and connected in series. The module will withstand design wind loading of 105 MPH for fixed tilt racking and is listed for UL 1703 (standard for listing Photovoltaic Modules). Each support post is anchored in the ground to the exact depth required to maintain a level array, preventing self-shading. A fixed tilt of 20.0 degrees with 180-degree azimuth is maintained by the mounting system. The angle was determined using NREL’s PV WATTS Program.
Electrical Connections include the AC Interface to the electrical system, which serves the Navy Exchange (NEX). IMC provided a stainless steel AC interface enclosure containing a contact managed by the control system. The enclosure houses an EMI filter for blocking interference from the inverter. An externally mounted AC disconnect with fuse protection provides for easy shutoff. The AC interface connects to the secondary electrical distribution through the new walk-in switchgear provided. Stainless steel string combiner boxes are used to collect the DC power produced in the module strings. For the DC side, a two conductor, 600 V DC system is utilized. Modules are bonded directly to the frame and connected to the DC system ground. The DC system ground is tied to the AC ground.
A grid interactive inverter turns the DC output from the PV modules into utility grade AC power to supplement the electricity for the NEX. The output of the inverter feeds an isolation transformer and provides power to the new walk-in outdoor switchgear. The walk-in outdoor switchgear provides a connection point for the PV system. The output of the new switchgear feeds the existing distribution point for the NEX and Automatic Transfer Switch (ATS).