Towards improving throughput and reducing latency: A simplified protocol conversion mechanism in distributed energy resources network

Abstract

With our research on communicating entities in heterogeneous Distributed Energy Resources (DERs), which utilize both IEC 61850 and other legacy interfaces, we show two things: firstly, (1) how the commonly deployed methods of achieving interoperability between incompatible interfaces can be altered to optimize throughput and latency; secondly, (2) how large an effect the optimization has by quantifying delay and throughput for the common method and our new method introduced in this paper.A prime objective of DERs is to enhance efficiency, stability and safety management during an emergency. Timely availability of operational data on DER entities in remote management centers will allow management software to extend the capabilities of, for example, an emergency generator to predict and correct for failure or operate more efficiently in a DER with mix of energy production types (solar, wind, petrol and so on). A DER often integrate a variety of entities which have proprietary incompatible interfaces (e.g. Modbus, DNP3, RS-485 and IEC 60870). To facilitate interoperability a protocol conversion mechanism is necessary. Here we concentrate on communication between the relatively modern IEC 61850, and Modbus, the most common proprietary interface.For our research, we built a new entity which integrates two other entities which are normally separate devices in a DER: a DER Management Server (DER-MS) and Modbus Feeder Master (MFM). Consolidating these two entities into a single box allows us to replace network inter-process communication with local inter-process communication, eliminating significant time sending messages from the remote management centers to peripheral elements in a DER (e.g. emergency generators) and back again. Using the same DER, we quantified network delay and throughput for: (a) our newly built simplified protocol conversion device and (b) the common configuration with MFM and DER-MS. We tested both configurations by benchmarking data requests from a remote management center to an emergency generator. Latency and throughput results obtained through experiment demonstrate that, our solution outperforms the common configuration with MFM and DER-MS.