Implementation and Analysis of a Secure Communication With SunSpec Modbus and Transport Layer Security Protocols for Short-Term Energy Management Systems

The growth of Renewable Distributed Generations (RDG) presents both a solution to common problems of traditional energy sources - such as the environmental impact and losses in transmission and distribution - and a challenge to appropriately control a large number of Distributed Energy Resources (DERs). The feasibility of such control depends on adequate communication protocols that, among other features, must address the security requirements of DER applications. This paper analyses the impact of a TLS-based SunSpec Modbus implementation on connection time and bulk data transfer when applied to short-term energy management systems. The protocol was tested with synthetic benchmarks, like the PI-MBUS-300, and was also deployed to the pilot-scaled short-term energy management system in the Pato Branco campus of the Federal University of Technology – Paraná. The results should be sufficient to characterize Modbus/TLS in normal operation with multiple cipher suites, as well as under abnormal situations that may cause frequent reconnections, like an unstable network.