Performance Evaluation of MQTT and CoAP Communication Protocols in IIoT for Electrical Substations Based on the IEC 61850 Standard

A solution for the integration of Smart Grid communication protocols is proposed through an IEC 61850 - IIoT (Industrial Internet of Things) test bench. The IIoT is one of the main implementations for the fourth industrial revolution, known as Industry 4.0. However, it is known that the incorporation of new technologies in the electricity sector, for monitoring systems and actuation by digital commands, are slower due to the requirements of efficiency and security in data transmission. Some of the most relevant IoT standards are: Constrained Application Protocol (CoAP) and Message Queue Telemetry Transport (MQTT). The implemented test bench allows the management of information through IEC 61850 services, with MQTT/COAP – IIoT messages, in an SF6 gas monitoring application. Likewise, it provides interoperability evaluations of isolated systems that use non-interoperable communication protocols in the substation and, therefore, are not capable of integrating monitoring signals and data into the SCADA system. Communication performance test results for both protocols, MQTT y CoAP, in the implemented IIoT platform and integration performance comparisons for digital substations are presented, showing the efficiency of the proposal.