Distributed Topology Inference for Power System Applications

Time: Fri 2019-10-04 10.00

Location: Ångdomen, Osquars backe 31, Stockholm (English)

Subject area: Electrical Engineering

Doctoral student: Nicholas Honeth , Elkraftteknik, Power System Dynamics, Operation and Control

Opponent: Prof. Valeriy Vyatkin, Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science

Supervisor: Prof. Lars Nordström, Elkraftteknik

Abstract

The electrical transmission and distribution system is undergoing unprecedented changes to meet the need for a carbon emission-free global energy system. An expected increase in the portion of end-user energy use in the form of electricity and need to integrate renewable energy sources into the power grid on a large scale require major changes in how power grids are operated and controlled.The systems and methods used to monitor, control and protect the power grid have developed in a context where the net power flow could be assumed to originate at large centralised power stations and be transmitted, distributed and delivered to end-users. The operation and control systems still largely follow a centralised and hierarchical structure with a control centre extending a multitude of connections out to automation systems over the geographical span of the grid. With the large-scale integration of distributed generation in the power system and the interconnection of grid infrastructures to facilitate inter-area trade of electricity, many of the premises on which traditional control systems were developed are currently changing. As more distributed generation capacity is integrated into parts of the power grid, efficient methods for determination of the electrical connectivity, the grid topology, become essential components for the development of all other control systems. The systems on which these methods are implemented must interoperate seamlessly with existing and future infrastructure. One effort to address this is an internationally coordinated standardisation process for power systems management and information exchange. The resulting standards, for example, IEC 61850 and IEC 61970, provide a framework for the development of new architectures and methods with a high level of interoperability whilst remaining applicable to the wide variety of equipment and applications that will be required. This thesis aims to test the hypothesis that distributing the application logic closer to the substation automation systems directly connected to the electrical process, provides a suitable architecture which can acquire system-wide knowledge of grid topologies without the assistance of a central entity. To achieve this, three research objectives are identified; proposing of novel control system architectures, utilising state-of-the-art structured data and equipment in substation automation systems and finally to develop a distributed topology inference algorithm utilising minimum prior knowledge of the grid it is acting within.The results firstly demonstrate the use of multi-agent systems as a distributed control and monitoring architecture. Secondly, the result demonstrates the application of relevant standardised IEC 61850 data models and interfaces for data exchange, and how they can be integrated into such architectures. Thirdly, the development of work on a multi-agent systems architecture and algorithm for distributed topology analysis of power grids is described and a formal description of the topology inference algorithm is given. Finally, a validation for the algorithm using a reference power grid model is presented.

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