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What Does it Take to Certify an Inverter for Use in Microgrids?

(Joseph Gottlieb, CTO, Wednesday September 23, 2020)

If you have been following the news over the past several months, the robustness of the public electricity grid is an issue that is getting significant coverage. Whether it is from grid stress due to excessively high daytime temperatures like we recently had in California, or transmission disruption because of natural disasters, the availability and robustness of the energy grid has become an issue for a lot of businesses. This has led to microgrids are increasingly of interest to both businesses and grid operators, especially when using distributed energy resources (DERs) such as photovoltaic (PV) solar or other renewable power sources.

One of the critical ingredients in a microgrid “recipe” are smart inverters. Since most microgrids are connected to the public energy grid at least on an intermittent basis, the smart inverter must be tested and certified to UL 1741-SA, also known as the Underwriters Laboratory standard for “Inverters, Converters, Controllers and Interconnection System Equipment for Use With Distributed Energy Resources”. Today, Rhombus Energy Solutions announced the certification of our RES-BESS60DP-480 30kW/60kW Multiport Smart Inverter to the UL 1741-SA standard. The Rhombus 30kW/60kW Multiport Smart Inverter is an ideal solution for microgrids and peak shaving applications, both for businesses and small industrial sites. The Rhombus Multiport Smart Inverter is a bi-directional inverter, and provides two 30kW DC ports. These DC ports can be connected to PV solar and battery-based energy storage resources, with each port supporting up to 30kW of DC electrical energy. The AC port can support up to 60kW of 208VAC or 480VAC power, and is also bi-directional. The 30kW/60kW Multiport Smart Inverter also incorporates the Rhombus VectorStat energy management system (EMS) controller and software, enabling the system to run software for peak shaving or other energy management applications.

Rhombus has built high-power inverters for renewable energy such as “behind the meter” grid energy storage systems for several years. We have applied that expertise to the design of our latest-generation bi-directional electric vehicle (EV) charging systems (which are designed from the start for the needs of fleet operators) and bi-directional smart inverter systems for microgrids. As a leader in the development and manufacturing of bi-directional, high-power systems for both vehicle charging and grid energy storage applications, Rhombus is unusually experienced in high-power charging systems for EVs, and  the area of V2G charging. Rhombus  also excels in the design and testing of high-power electrical equipment to meet the requirements of UL and other certification organizations. We have built hundreds of V2G-capable high-power, high-reliability chargers for a variety of different sizes and classes of EVs. Find out how we can help you by contacting us at, or by reading our Vehicle to Grid Solution Brief.

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