Evaluating XMPP Communication in IEC 61499-based Distributed Energy Applications

The IEC 61499 reference model provides an international standard developed specifically for supporting the creation of distributed event-based automation systems. Functionality is abstracted into function blocks which can be coded graphically as well as via a text-based method. As one of the design goals was the ability to support distributed control applications, communication plays a central role in the IEC 61499 specification. In order to enable the deployment of functionality to distributed platforms, these platforms need to exchange data in a variety of protocols. IEC 61499 realizes the support of these protocols via "Service Interface Function Blocks" (SIFBs). In the context of smart grids and energy applications, IEC 61499 could play an important role, as these applications require coordinating several distributed control logics. Yet, the support of grid-related protocols is a pre-condition for a wide-spread utilization of IEC 61499. The eXtensible Messaging and Presence Protocol (XMPP) on the other hand is a well-established protocol for messaging, which has recently been adopted for smart grid communication. Thus, SIFBs for XMPP facilitate distributed control applications, which use XMPP for exchanging all control relevant data, being realized with the help of IEC 61499. This paper introduces the idea of integrating XMPP into SIFBs, demonstrates the prototypical implementation in an open source IEC 61499 platform and provides an evaluation of the feasibility of the result.Comment: 2016 IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA

Towards a Systematic Approach for Smart Grid Hazard Analysis and Experiment Specification

The transition to the smart grid introduces complexity to the design and operation of electric power systems. This complexity has the potential to result in safety-related losses that are caused, for example, by unforeseen interactions between systems and cyber-attacks. Consequently, it is important to identify potential losses and their root causes, ideally during system design. This is non-trivial and requires a systematic approach. Furthermore, due to complexity, it may not possible to reason about the circumstances that could lead to a loss; in this case, experiments are required. In this work, we present how two complementary deductive approaches can be usefully integrated to address these concerns: Systems Theoretic Process Analysis (STPA) is a systems approach to identifying safety-related hazard scenarios; and the ERIGrid Holistic Test Description (HTD) provides a structured approach to refine and document experiments. The intention of combining these approaches is to enable a systematic approach to hazard analysis whose findings can be experimentally tested. We demonstrate the use of this approach with a reactive power voltage control case study for a low voltage distribution network.Comment: 2020 IEEE 18th International Conference on Industrial Informatics (INDIN

ERIGrid Holistic Test Description for Validating Cyber-Physical Energy Systems

Smart energy solutions aim to modify and optimise the operation of existing energy infrastructure. Such cyber-physical technology must be mature before deployment to the actual infrastructure, and competitive solutions will have to be compliant to standards still under development. Achieving this technology readiness and harmonisation requires reproducible experiments and appropriately realistic testing environments. Such testbeds for multi-domain cyber-physical experiments are complex in and of themselves. This work addresses a method for the scoping and design of experiments where both testbed and solution each require detailed expertise. This empirical work first revisited present test description approaches, developed a newdescription method for cyber-physical energy systems testing, and matured it by means of user involvement. The new Holistic Test Description (HTD) method facilitates the conception, deconstruction and reproduction of complex experimental designs in the domains of cyber-physical energy systems. This work develops the background and motivation, offers a guideline and examples to the proposed approach, and summarises experience from three years of its application.This work received funding in the European Community’s Horizon 2020 Program (H2020/2014–2020) under project “ERIGrid” (Grant Agreement No. 654113)

Energy Systems Test Case Discovery Enabled by Test Case Profile and Repository

Smart energy systems comprise multiple domains like power, thermal, control, information, and communication technology, which increases the complexity of research and development studies. This expansion also requires larger and ever so complex experimental pilot environments driving the demand for geographically distributed multi-research infrastructure tests. The Holistic Test Description approach supports the design of multi-domain and multi-research infrastructure tests by orga-nizing the test cases into comprehensive segments, ensuring all relevant items for testing are covered. These test cases eventually form a pool, which to understand holistically would require studying and reading all the descriptions. This work proposes therefore the concept of Test Case Profiles to improve test case discovery and the structured creation of them. Test Case Profiles add further structure to the indexing in test case repositories. Along with the proposed indexing method, four different use cases are introduced to motivate additional applications of the proposed concept.Energy Systems Test Case Discovery Enabled by Test Case Profile and RepositoryacceptedVersio

Model-driven engineering for smart grid automation

The rollout of smart grid solutions has already started with new and intelligent methods being deployed to today's power systems. One of the main catalysts for this is the massive deployment of renewable energy sources in the recent years, causing new challenges for the planning and operation of the electric power system. Automation systems, using advanced information and communication technologies, are key elements to handle these new challenges. The electric energy system is moving from a single system to a system of systems. As a consequence, engineers are also faced with an increasing engineering complexity. To mitigate this complexity, proper methods and tools are needed also for the overall engineering process. Until now, such a method has been missing. This work addresses these shortcomings with the concept for a rapid engineering methodology, covering the overall engineering process for smart grid applications—from use case design to validation and deployment. The main goal with the methodology is to improve the traditional smart grid engineering process in such a way that manual work and complexity are reduced. In order to achieve this automation, techniques from model-driven engineering is used. The main result of the work is a formal approach for specification and design together with a concept for automatic generation and deployment of target code and configurations. The rapid engineering methodology is also compared to the performance of traditional smart grid engineering methods. It shows that the rapid engineering methodology drastically reduces the engineering and validation complexity for the engineer. At the same time, the manual effort is reduced and the rapidness of current engineering methods is significantly increased.20

Engineering Smart Grids: Applying Model-Driven Development from Use Case Design to Deployment

The rollout of smart grid solutions has already started and new methods are deployed to the power systems of today. However, complexity is still increasing as focus is moving from a single system, to a system of systems perspective. The results are increasing engineering efforts and escalating costs. For this reason, new and automated engineering methods are necessary. This paper addresses these needs with a rapid engineering methodology that covers the overall engineering process for smart grid applications—from use case design to deployment. Based on a model-driven development approach, the methodology consists of three main parts: use case modeling, code generation, and deployment. A domain-specific language is introduced supporting the use case design according to the Smart Grid Architecture Model. It is combined with the IEC 61499 distributed control model to improve the function layer design. After a completed use case design, executable code and communication configurations (e.g., IEC 61850) are generated and deployed onto compatible field devices. This paper covers the proposed rapid engineering methodology and a corresponding prototypical implementation which is validated in a laboratory experiment. Compared to other methods the proposed methodology decreases the number of engineering steps and reduces the use case design and implementation complexity

An Adaptable Engineering Support Framework for Multi-Functional Energy Storage System Applications

A significant integration of energy storage systems is taking place to offer flexibility to electrical networks and to mitigate side effects of a high penetration of distributed energy resources. To accommodate this, new processes are needed for the design, implementation, and proof-of-concept of emerging storage systems services, such as voltage and frequency regulation, and reduction of energy costs, among others. Nowadays, modern approaches are getting popular to support engineers during the design and development process of such multi-functional energy storage systems. Nevertheless, these approaches still lack flexibility needed to accommodate changing practices and requirements from control engineers and along the development process. With that in mind, this paper shows how a modern development approach for rapid prototyping of multi-functional battery energy storage system applications can be extended to provide this needed flexibility. For this, an expert user is introduced, which has the sole purpose of adapting the existing engineering approach to fulfill any new requirements from the control engineers. To achieve this, the expert user combines concepts from model-driven engineering and ontologies to reach an adaptable engineering support framework. As a result, new engineering requirements, such as new information sources and target platforms, can be automatically included into the engineering approach by the expert user, providing the control engineer with further support during the development process. The usefulness of the proposed solution is shown with a selected use case related to the implementation of an application for a battery energy storage system. It demonstrates how the expert user can fully adapt an existing engineering approach to the control engineer’s needs and thus increase the effectiveness of the whole engineering process

Online Reasoning about the Root Causes of Software Rollout Failures in the Smart Grid.

An essential ingredient of the smart grid is software-based services. Increasingly, software is used to support control strategies and services that are critical to the grid's operation. Therefore, its correct operation is essential. For various reasons, software and its configuration needs to be updated. This update process represents a significant overhead for smart grid operators and failures can result in financial losses and grid instabilities. In this paper, we present a framework for determining the root causes of software rollout failures in the smart grid. It uses distributed sensors that indicate potential issues, such as anomalous grid states and cyber-attacks, and a causal inference engine based on a formalism called evidential networks. The aim of the framework is to support an adaptive approach to software rollouts, ensuring that a campaign completes in a timely and secure manner. The framework is evaluated for a software rollout use-case in a low voltage distribution grid. Experimental results indicate it can successfully discriminate between different root causes of failure, supporting an adaptive rollout strategy

Rapid Prototyping of Multi-Functional Battery Energy Storage System Applications

Battery Energy Storage Systems (BESS) are starting to play an important role in today’s power distribution networks. They provide a manifold of services for fulfilling demands and requests from diverse stakeholders, such as distribution system operators, energy market operators, aggregators but also end-users. Such services are usually provided by corresponding Energy Management Systems (EMS). This paper analyzes the complexity of the EMS development process resulting from an evolving power utility automation