Case Study — How a Solar Farm Used Load Bank Testing to Simulate the Grid

By relying on load bank testing to commission its facilities, E Light Electric, a renewable energy company, realized major benefits. E Light Electric specializes in constructing large-scale renewable projects. The company has completed projects across several sectors, including utility, government and commercial projects. It has installed and maintained solar energy systems in multiple applications.

In 2015, Solar Power World magazine ranked E Light Electric the #1 Electrical Subcontractor, the #1 Colorado Solar Contractor and #12 on its list of the “Top 500 Solar Contractors.”

After partnering with ComRent, E Light Electric overcame issues and executed successful load bank testing. ComRent managed a load bank testing project for E Light Electric that simulated the power grid. The Bakersfield, California project included two 600KW TMEIC inverters per inverter pad, for a total of 96 inverters scheduled for commissioning.

Using load banks for grid emulation allowed E Light Electric to:

  • Test Medium Voltage Cables — Most solar farms have their medium voltage cable from the substation to the inverter pads buried underground. Allowing the medium voltage cables to be tested with grid emulation verified the capability of their newly installed cable.
  • Utilize All On-Site Staff – By energizing the entire site, all available staff could work on different inverter pads simultaneously. Inverter, electrical and solar array crews worked together during the grid emulation to test inverters, inspect electrical connections, check phase rotation and set GPS tracking systems at any section of the solar field.
  • Track Systems and Adjust Arrays – The grid emulation activated the tracking systems so every solar panel on the jobsite was tracking the sun’s position. The solar array teams took measurements of the panels and adjusted on their tracking systems, if needed. Load bank testing ensured the mechanics of the entire solar site.
  • Verify Array Sleep and Wake Modes — The project tracked the arrays for one full day so the system could go into a sleep mode when the sun went down. The next day when the sun came up, the team confirmed all the system operated as intended.

Contrary to what many operators believe, solar projects involve much more than just inverter testing. The E Light Electric project also required testing the medium voltage cable, dialing in the GPS systems and physically moving the photovoltaic panels.

Simulating the grid using grid emulation ensures the most complete commissioning until utility power is provided. When utility power is available, the least amount of work will be needed for the solar farm to go fully live.

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For a detailed discussion on utility commissioning, download ComRent’s latest eBook – “Understanding the Commissioning Process for Utility Systems.” This resource discusses the importance of following established standards and proven processes during utility commissioning. It will explain how successful commissioning can lead to greater control, more efficient operations and lower costs.

ComRent’s team of experts is ready to help ensure your system is successfully commissioned. We are offering a complimentary consultation to review your project and propose the right load bank solution for your requirements. Contact us today.

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