Model-Based Systems Engineering (MBSE) is a formal method that is used to support analysis, design, independent verification, and validation inherent in the development of software and hardware systems. MBSE applications are present in many areas of our daily lives, including manufacturing, robotics, healthcare, automation, etc. However, despite their rapid and sustainable growth during the last few years, the MBSE methods themselves are quite far away from perfect. There are some current problems, which resist more rapid penetration of MBSE systems in their development. One of them is that currently the majority of MBSE systems are vendor dependent and, as a result, they have poor compatibility with each other. Furthermore, currently, there is a gap between the design of a digital model and a control model of an engineering system. Currently, this problem is usually solved by involving two or more groups of engineers, where each of these groups works on their own problems. All this costs companies additional engineering time and, as a result, development costs. Therefore new, and more sophisticated approaches for the generation of MBSEs are needed in order to overwhelm the challenges highlighted above.

In order to narrow the field of study and better concentrate on specific problems, smart power distribution systems have been chosen as the main research object for this dissertation. Thus, in this work, the author introduces Model-Integrated Systems Engineering (MISE), as the MBSE sub-discipline. Here and later in this paper, the author will refer to MISE as the main area of interest. Also, the author uses the term DigitalTwin to refer to the multilayered structure of a complex distributed automation system consisting of three layers, namely:– the static machine-readable information about the infrastructure of the smart energy system,– the simulation model layer,– the distributed control layer for the investigated smart energy system.

In general, two new transformation approaches for automatic MISE generation are discussed in the scope of this dissertation, namely:1. Transformation of the System Configuration Design (SCD) files of an electric system(presented in IEC 61850) into the corresponding SIMULINK model.2. Transformation of specification files of electronic components into corresponding OPC UA information model.All discussed approaches are implemented in the form of a program code that is publicly available on the Internet.

The IEC 61850 and OPC UA standards are considered key components of the current dissertation. IEC 61850 is an international standard covering different sides of smart energy distribution systems including communication protocols for diverse equipment in a substation, including protection, control, and measurement equipment, as well as intelligent electronic devices (IEDs). Information Modeling OPC UA is a platform-independent service-oriented architecture that combines the concepts of semantic modeling.

First, the structure of the IEC 61850 standard is discussed, as well as its potential benefits for the MISE of smart power distribution systems in terms of the automatic transformation of the information model.

Next, the architecture of the electrical system (the SCD file) of the electrical vehicle (EV) charging station (CS) is proposed as an example. The aim is to design a mechanism for the automatic transformation of MISE in two domains, namely:- Physical model of the electrical system itself,- Automatically build a communication channel between the digital replica (the model) of the electrical system and the virtual energy management system (EMS).

Thus, this work aims to contribute to the design and virtual commissioning of Digital Twin systems, as well as to improve the interoperability between IEC 61850 compliant systems and electric vehicle charging stations (paper C explains that in more detail).

Finally, by narrowing down the scope of the investigation to one specific electrical device, a new approach for converting integrated circuit (IC) specification files of an electric system into an OPC UA information model is discussed. The designed transformation algorithm is based on the directed graphs theory (paper D explains that in more detail). The purpose of this work is to highlight and contribute to the problems of the MISE analysis solutions. 

In summary, the work presented in this dissertation raises questions about interoperability between different standards, the problems of converting the IEC 61850 information model into MISE, verification of the generated MISE compared to the original IEC 61850 information model, and the problems of forming an information model OPC UA.

Model-Based Systems Engineering (MBSE) is a method that is used to support analysis, design, independent verification, and validation inherent in the development of software and hardware systems. MBSE applications are present in many areas of our daily lives, including manufacturing, robotics, healthcare, automation, etc. However, despite their rapid and sustainable growth during the last few years, the MBSE methods themselves are quite far from perfect. There are some current problems, which resist more rapid penetration of MBSE systems in their development. One of them is the issue of interoperability between different MBSE tools since most of them are vendor-specific. Although vendor dependency has been a problem well before the conceptualization of MBSE this problem is especially actual for the MBSE due to the heterogeneity of the concepts (model, systems thinking, and systems engineering) that it is based on. Furthermore, there is currently a gap between the development of a simulation model and the development of a control system for that model. Currently, this problem is usually solved by involving two or more groups of engineers, where each of these groups works on their problems. All this costs companies additional engineering time and, as a result, development costs. Therefore, new, and more sophisticated approaches for the generation of MBSEs are needed to overcome the challenges highlighted above

To narrow the field of study and better focus on specific problems, smart power distribution systems have been chosen as the main research object for this dissertation. Furthermore, the author uses the term Digital Twin to refer to the multilayered structure of the complex distributed automation system consisting of three layers, that is:

– the static machine-readable information about the infrastructure of the smart energy system,

– the simulation model layer,

– the distributed control layer for the investigated smart energy system.

In particular, the semi-automated approach is presented in Article C of this thesis. The proposed approach is semi-automated because it generates the MATLAB script of the simulation model rather than the model itself. To generate the model, the user needs to automatically generate it in MATLAB (a link to a detailed video describing this process is provided in Article C). IEC 61850 specification files, written in substation configuration language, are used as a starting point for further conversions.

The IEC 61850 standard is a key component of the current dissertation. IEC 61850 is an international standard that covers different sides of smart energy distribution systems, including communication protocols for diverse equipment in a substation, including protection, control, and measurement equipment, as well as intelligent electronic devices(IEDs).

The dissertation consists of five papers, each of which aims at a specific goal, namely:

– Paper A touches upon interoperability problems between information architecture of different communication protocols (IEC61850/GOOSE - transformer substations, OpenADR - smart buildings, OCPP - electric vehicles), and proposes a concept for solving that problem.

– Paper B describes the design challenges of the SIMULINK model, which is considered the modeling layer of the multi-layer structure of the Digital Twin. As an example, a model of a datacenter is evaluated, designed, and validated against real data.

– In Paper C, an approach for information model automatic transformation from IEC61850 to OCPP is proposed. A test programming application was built, based on the proposed approach, and the generated OCPP information model was tested with the help of third-party programming tools.

– Paper D presents a performance analysis of the BeagleBone Black as an IEC61850Merging Unit simulator. The goal is to determine how well BeagleBone Black’shardware and software performance meets the IEC61850 Merging Unit requirements.– Paper E reveals an approach for converting a MATLAB/SIMULINK model to an FPGA-in-Loop system. The goal is to make a step towards automation of the digital twin design process and discuss the various barriers to achieving it.

Thus, the work presented in this dissertation raises questions about compatibility between different standards, the problems of converting the IEC 61850 information model to MBSE, the verification of the generated MBSE against the original IEC 61850 information model, the problems of hardware incompatibility with the target programming application, and the problems designing a Digital Twin model from SIMULINK (as an example in this thesis).