A protection relay test set from OMICRON electronics
Headquartered in Klaus, Austria, OMICRON  specializes in testing equipment for electrical power systems. Its products are used worldwide—among them, the new CMC 500 protection relay test set. In combination with powerful software, the CMC 500 tests the functionality, settings, and correct operation of protection relays by simulating faults in the power grid. Protection relays play a crucial role in energy systems by quickly detecting network faults and isolating affected sections to prevent equipment damage and minimize downtime. To ensure their reliability, these relays must be tested regularly.

More than 15,000 units of the CMC 356—its predecessor—are in operation around the globe, with some in use for over 15 years. It was time for a new generation. The OMICRON product team took this as an opportunity to engage directly with users, gathering insights into current challenges and future needs. The energy sector is undergoing a significant transformation due to the energy transition. In addition to expanding the grid, modernizing existing infrastructure has become essential. As a result, efficient testing—both during the commissioning of new substations and in the maintenance of existing assets—has become more important than ever.

Instead of making incremental updates to the CMC 356, which has been in use since 2008, OMICRON opted for a complete redesign with the CMC 500. The new device incorporates four advanced current and voltage generators that can be flexibly combined in a modular setup. These switchable generator modules deliver amplitudes of up to 300 V and 30 A, and frequencies of up to 5 kHz. The high-current module reaches 60 A per channel or up to 180 A single-phase. The most powerful of the five device configurations can generate up to 450 A in single-phase operation. Achieving this level of performance in such a compact form factor required sophisticated thermal design.

Since many users operate CMC devices in the field—such as at industrial facilities, within transportation infrastructure, or at substations—the new unit had to be lightweight, compact, robust, and versatile enough to support a wide range of applications. In all these respects, the CMC 500 offers significant advantages over the previous flagship of the CMC series.

The CMC 500 also addresses two major industry trends: increased focus on operator safety during testing, and rising cybersecurity requirements—driven both by the growing threat landscape and new regulatory demands. The development of the CMC 500 prioritized strict compliance with safety standards and leveraged OMICRON’s expertise from its existing cybersecurity product line.

The result is a device that raises the bar for protection relay testing—capable of meeting not only today’s demands but also those of the future. Launched in February 2025, the CMC 500 is tailored to the needs of utilities, service providers in the energy sector, and industrial companies.