This paper presents a time-triggered protocol designed for decentralized control applications that use Ethernet line or ring networks. The protocol was developed based on the requirements of Modular Multilevel Converters currently used
in electric power systems. It reduces the nodes forwarding delay
and cycle time to a minimum by exploring the combination of a
global set-point dissemination with distributed local adjustments. We have validated the overall concept with an OMNeT++ model and tested the forwarding implementation using a Field Programmable Gate Array. A comparison with EtherCAT, Profinet IRT and VABs shows that the proposed protocol has shorter cycle times.