Project Highlight

Vietnam Electricity Achieves Reliability in Harsh Environments With SEL Relays in the Yard


EVN, with the help of their system integrator, ATS, placed cabinets with SEL devices in the substation yard, close to the primary equipment. EVN chose SEL relays because they are durable enough to withstand Vietnam’s harsh environment. ATS used two fiber-optic cables to connect the relays to the control house, reducing the use of copper and the number of faults resulting from harsh weather conditions.

Placing the relays in the yard lowered the costs and commissioning time of the modernization project and made the system more reliable by removing copper conductors from underground trenches.


Problems in the system are detected and mitigated immediately using fiber-optic channels instead of underground copper conductors. In the more than ten years since they were installed, the SEL relays have not experienced a single environmental failure.

“Vietnam is a country located in a tropical monsoon region. The temperature and humidity are very high, and many areas encounter flood situations annually. So, when we designed a solution for using the devices outside, we also considered the tolerance of SEL’s devices, because environmental conditions in the cabinet can reach 85°C (185°F) and humidity can reach 95%.”
Thai TranVice General Director ATS

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