Dag Eirik Nordgård

Integrating risk analysis and multi-criteria decision support under uncertainty in electricity distribution system asset management

Abstract Asset managers in electricity distribution companies generally recognize the need and the challenge of adding structure and a higher degree of formal analysis into the increasingly complex asset management decisions. This implies improving the present asset management practice by making the best use of the available data and expert knowledge and by adopting new methods for risk analysis and decision support and nevertheless better ways to document the decisions made. This paper discusses methods for integrating risk analysis and multi-criteria decision support under uncertainty in electricity distribution system asset management. The focus is on how to include the different company objectives and risk analyses into a structured decision framework when deciding how to handle the physical assets of the electricity distribution network. This paper presents an illustrative example of decision support for maintenance and reinvestment strategies based, using expert knowledge, simplified risk analyses and multi-criteria decision analysis under uncertainty.

Application of Bayesian networks for risk analysis of MV air insulated switch operation

Electricity distribution companies regard risk-based approaches as a good philosophy to address their asset management challenges, and there is an increasing trend on developing methods to support decisions where different aspects of risks are taken into consideration. This paper describes a methodology for application of Bayesian networks for risk analysis in electricity distribution system maintenance management. The methodology is used on a case analysing safety risk related to operation of MV air insulated switches. The paper summarises some challenges and benefits of using Bayesian networks as a part of distribution system maintenance management.

Handling maintenance priorities using multi criteria decision making

This paper presents an analysing strategy for prioritising a power companys different types of maintenance projects. Qualitative criteria, such as for instance safety for personnel and effect on the environment, together with the economic figures, form the decision framework. The handling of qualitative criteria is assisted using the AHP (analytic hierarchy process) method to structure the decision criteria and to obtain the relative weighting between different criteria. The analysing strategy is demonstrated by using case studies from maintenance decisions in hydropower plants.

Risk-based method for cost-effective reinvestments in distribution networks

In deregulated power markets, electricity utilities are now facing new challenges concerning revenue cap regulations, including quality based incentives. When planning the network every grid investment should contribute to minimising the total costs related to the investment within given safety and environmental requirements. This paper describes a method used for planning the time of replacement for network components. By using the method, the utility considers both qualitative and economic criteria that have to be taken into account when evaluating different solutions. The paper also describes experience from a Norwegian utility using the method when planning renewal of distribution substations.

Clustering Distributed Generation using the instantaneous Euclidean Distance in polar coordinates

Adequate modeling of active distribution grids in transmission system analysis require the use of dynamic equivalents. This paper presents a new method to determine the electromechanical coherency between synchronously based distributed generators. The proposed method allows the computation of the instantaneous Euclidean Distance in polar coordinates for clustering Distributed Generation units in a test power system.

External grid representation for assessing fault ride through capabilities of distributed generation units

The existing power systems are challenged as the share at MV distribution level of distributed generation is increasing. In order to ensure the security of operation and power quality in these grids, transmission and distribution power system operators have issued connection and operation guidelines related to integration of distributed generation. Some of these guidelines are designed to assess fault ride-through capabilities when dynamic connection studies are performed for distributed generation units. While most of the ongoing research have addressed especially the fault ride-through capabilities of the investigated generation unit when the most severe fault occur close to the point of common coupling, some research questions remain related to the adequacy of the representation of the external grid. This paper will compare several representations of external grid proposed by different authors for achieving more accurate results of fault ride-through capabilities of small scale hydro units.

Methodology for planning of distributed generation in weak grids

Distributed generation (DG) units are increasing in number all over the world, thus providing new opportunities, but also challenges for distribution system operators. This paper briefly describes the status for integration of DG in Norway, highlighting challenges that Norwegian distribution network companies are facing with regard to large scale integration of DG, typically small scale hydro. The paper further reports from a survey describing some aspects of DG integration and existing planning methodologies among distribution network companies. An overall methodology for planning of integration of DG is presented, highlighting different aspects of inherent uncertainty in the planning process. The methodology can be used by the distribution system operators to develop long term network plans taking into consideration the local potential for DG, but also the uncertainty (in terms of timing, location and capacity) for DG development.

Methodology for risk-informed maintenance and reinvestment decisions

This paper presents a methodology for risk-informed maintenance and reinvestment decision support in distribution companies. The methodology incorporates different analyses such as simplified risk analyses, quantitative risk analyses and economic analyses, into a multi-criteria decision support framework. The goal of the methodology is to provide formal decision support for asset managers in distribution companies.

Using risk analyses in a multi criteria decision making framework for evaluation of hydropower maintenance projects

The paper presents a framework for using risk analysis together with multi criteria decision making methods as an analysing strategy for evaluating and prioritising different types of maintenance and renewal projects within a power company. Projects are being subject to risk evaluation related to a set of qualitative criteria, together with calculation of economic key figures such as the net present value of the project. The basics of the strategy are illustrated by experience data from risk evaluation of the project portfolio of a Norwegian hydropower production company.

Solutions from a national Smart grids demonstration site exploring a fiber-optic communication infrastructure

The paper presents general background and drivers for the development of Smart grids technologies in Norway, with emphasis on the need for and status on developing national demonstration sites for technology testing and validation. The paper further presents the demonstration site which is being developed at Steinkjer, and what solutions which are being established in the first stagee of developing this living laboratory.