Case Study: CEZ extends nuclear plant protection lifespan and cuts upgrade costs with Schweitzer Engineering Laboratories (SEL)

CEZ extends generator protection lifespan and saves millions with Schweitzer Engineering Laboratories

The customer, CEZ, a Czech power system operator, faced a challenge while upgrading the generator protection systems at its Temelín nuclear power plant. Replacing obsolete protective relays from vendor Schweitzer Engineering Laboratories (SEL) was complicated because other vendors insisted the plant's aging current transformers (CTs) also had to be replaced, a process that would cause costly extended downtime.

Schweitzer Engineering Laboratories (SEL) used its Real Time Digital Simulator to perform hardware-in-the-loop testing. This proved its SEL-400G relays could operate reliably with the existing CTs using nonstandard settings, eliminating the need for their replacement. This solution, which included prewired direct-replacement assemblies, saved CEZ millions of dollars in avoided costs and prevented extended downtime, allowing the project to be completed on schedule during a planned outage.

CEZ