Nicholas Honeth

Virtualization of synchronized phasor measurement units within real-time simulators for smart grid applications

Synchronized phasor measurement units (PMUs) provide GPS-time tagged, high-sampling rate, positive-sequence voltage and current phasors. When placed in high-voltage substations in power networks, PMUs can provide real-time information that is necessary for the development of Smart Transmission Grids software applications whose main objective is to improve the power systems monitoring, control and protection. The development of these applications, particularly for use within control centers for on-line purposes, is limited by the availability of and access to real-time PMU data and other information. One attractive approach for application development is the use of real-time simulators to which PMUs can be interfaced as hardware-in-the-loop (HIL) devices to harvest PMU data. However, this approach has technical and economical limitations, which can be tackled by the virtualization of PMU devices. This article describes the development of an entirely software-based synchronized phasor measurement unit for use within real-time simulators to emulate a large number of real-life PMUs, which in turn can be used for creating new phasor-based applications.

Using enterprise architecture and technology adoption models to predict application usage

Application usage is an important parameter to consider in application portfolio management. This paper presents an enterprise architecture analysis framework which can be used to assess application usage. The framework, in the form of an architecture metamodel, incorporates variables from the previously published Technology Acceptance Model (TAM) and the Task-Technology Fit (TTF) model. The paper describes how the metamodel has been tailored for a specific domain, viz. industry maintenance management. The metamodel was tested in the maintenance management domain through a survey with 55 respondents at five companies. Data collected in the survey showed that the domain-specific metamodel is able to explain variations in maintenance management application usage. Integrating the TAM and TTF variables with an architecture metamodel allows architects to reuse research results smoothly, thereby aiding them in producing good application portfolio decision-support.

A case study of multi-agent interoperability in IEC 61850 environments

The IEC 61850 is the most promising standard for design of substation communication and automation systems. On the other hand multi-agents systems are attracting growing interest for different applications of substation automation systems. In multiagent systems agents represent different stake holders in the power system and based on implemented decision making logic they determine optimal operational conditions for the power systems given boundary conditions. Interoperability is of course a necessary pre-requisite for such architectures. Here we identify two aspects of interoperability; horizontal and vertical. Horizontal interoperability is relies on common semantic models of the power system that the agents can use to make decisions. One such semantic model is presented in the IEC 61970 Common Information Model (CIM). At this level, the IEC 61850 standard provides a model for access to information and control functions that has the necessary flexibility needed. In this paper we discuss the mapping between a multi-agent based architecture for power system control and the IEC 61850 standard for utility automation. The mapping is based on a use-case drive approach, in which the information exchange need is defined by the multi-agent system.

Application of the IEC 61850-7-420 data model on a Hybrid Renewable Energy System

IEC 61850 is the most promising standard for design of substation communication and automation systems. Recent revisions of the standard include support for modeling, and control of Distributed Energy Resources (DER). This paper presents an application of the IEC 61850-7-420 data model for DER in the implementation of a control and energy management system for a Hybrid Renewable Energy System (HRES). These systems are beginning to prove their usefulness in providing deployable electrical supply in locations where no such supply exists as well as for backup power or power quality related support functions. The motivation for applying the standard to the design process is twofold; to modularize the design according to an accepted international standard and to design for interoperability with other IEC 61850 enabled devices and SCADA systems.

Using enterprise architecture analysis and interview data to estimate service response time

Insights into service response time is important for service-oriented architectures and service management. However, directly measuring the service response time is not always feasible or can be very costly. This paper extends an analytical modeling method which uses enterprise architecture modeling to support the analysis. The extensions consist of (i) a formalization using the Hybrid Probabilistic Relational Model formalism, (ii) an implementation in an analysis tool for enterprise architecture and (iii) a data collection approach using expert assessments collected via interviews and questionnaires. The accuracy and cost effectiveness of the method was tested empirically by comparing it with direct performance measurements of five services of a geographical information system at a Swedish utility company. The tests indicate that the proposed method can be a viable option for rapid service response time estimates when a moderate accuracy within 15% is sufficient.

Decentralized topology inference of electrical distribution networks

Power system operation and control relies heavily on models for decision making. Topology is a critical part of producing these models and maintaining up-to-date topologies of electrical distribution networks is a resource consuming and challenging task. This paper proposes a methodology and system architecture for inference of electrical topology using process and model data from IEC 61850 compliant substation automation devices. A system of autonomous intelligent agents communicating via an overlay network is proposed where agents are capable of communicating on the IEC 61850 station bus. An algorithm for topology inference using structured exchange and comparison of process and model information is developed. The capabilities of structured information exchange and interfacing of substation automation devices enables plug-and-play operation of the topology inference requiring minimal prior knowledge of electrical network structure. Decentralized topology inference forms the basis for future work in operation and management of active distribution networks.

A Local Market Model for Urban Residential Microgrids with Distributed Energy Resources

Widespread adoption of onsite distributed generation providing households with their electricity supply could make them very significant actors in terms of their aggregated impact on the wider electric power system. This paper proposes an approach which brings community engagement to the case of distributed energy resource based electricity supply for urban residential buildings. Considering a future case for Stockholm, a community ownership and service-oriented setup is proposed which fosters the creation of a market for both traditional and new stakeholders in the electric power system while ensuring the integrity of control by individual apartments. Salient features include a hypothetical pricing model which encourages local trade of electricity between apartments guided by individual apartment behavior and decision making through bid strategies. A set of research themes devoted to understanding the trends in effect of changes in the integral concept components have been identified through simulations and subjected to initial analysis.

Trustworthy Injection/Curtailment of DER in Distribution Network maintaining quality of Service

Future powers system is considering huge flux of information flow due to increase in Renewable Energy Sources. Due to the limited monitoring and management of SCADA systems, inclusion of DER at local distribution level is a challenging task for the Smart Grid. We discuss the non-functional requirement aspects and their implication in trustworthy systems. The paper also illustrates an engineering approach towards trustworthy ICT systems. We present a use case about Injection/Curtailment of DER in distributed network. Further, we argue the importance of Service Level Agreements as coordination tool for information exchange between DSO and DER for the provisioning of trustworthy services. Finally conclude that modeling of SLA using Multi Agent Systems is a viable approach towards Trustworthy future Smart Grid applications.

Test platform for synchrophasor based wide-area monitoring and control applications

Synchrophasor technology is considered as a main enabler for the envisioned Smart Grid at the transmission level. Despite some preliminary field test results reported from China Southern Grid, the majority of the synchrophasor applications are still in the engineering or advanced laboratory tests phases. One possible impedance of any real-life adoption of such applicationsis a lack of test platforms that are able to verify the proposed application paradigms in cost efficient manners, and also to demonstrate the interactions between the power system and the supporting ICT systems with sufficient details. In this paper, we report on the continuing research efforts targeting at developing a test platform for the development of the synchrophasor based applications. The platform incorporates a virtual Phasor Measurement Unit (PMU), a real-time simulator for power systems, a real-time simulator for communication networks, and an implementation of an open-source Phasor Data Concentrator. Specifically, this article focuses on the implementation and verification of the virtual PMU, and on the extension of its functionality to incorporate communication over UDP.

A method to identify exposed nodes in low voltage distribution grids with High PV penetration

The impact of introducing distributed energy resources at the low voltage side of the distribution grid is currently raising new challenges for utilities. In particular, the high penetration of photovoltaic panels (PVs) in radial grids is increasing the active power losses in the branches and the voltage level at some of the nodes. Principally nodes next to PV array installations. This paper presents a methodology based on design of experiments (DOE) to detect such exposed nodes and branches, together with the identification of the main scenarios that cause such problems, characterized by: season, type of day, solar radiation and outdoor temperature levels. The methodology is simulated on a LV network based on the Cigre benchmark Grid with real utility data. The exposed nodes are classified for each feeder from most to least problematic and showed (as expected) sensitivity to seasonality (summertime), characterized by high solar radiation and outdoor temperatures.