Combined Unbalanced Distribution System State and Line Impedance Matrix Estimation

To address the challenges that the decarbonization of the energy sector is bringing about, advanced distribution network management and operation strategies are being developed. Many of these strategies require accurate network models to work effectively. However, distribution network data are known to contain errors, and attention has been given to techniques that allow to derive improved network information. This paper presents a novel method to derive line impedance values from smart meter measurement time series, with realistic assumptions in terms of meter accuracy, resolution and penetration. The method is based on unbalanced state estimation and is cast as a non-convex quadratically constrained optimization problem. Both line lengths and impedance matrix models can be estimated based on an exact nonlinear formulation of the steady-state three-phase network physics. The method is evaluated on the IEEE European Low Voltage feeder (906 buses) and shows promising results

Smart Energy Network Digital Twins: Findings from a UK-Based Demonstrator Project

Digital Twins promise to deliver a step-change in distribution system operations and planning, but there are few real-world examples that explore the challenges of combining imperfect model and measurement data, and then use these as the basis for subsequent analysis. In this work we propose a Digital Twin framework for electrical distribution systems and implement that framework on the Smart Energy Network Demonstrator microgrid in the UK. The data and software implementation are made available open-source, and consist of a network model, power meter measurements, and unbalanced power flow-based algorithms. Measurement and network uncertainties are shown to have a substantial impact on the quality of Digital Twin outputs. The potential benefits of a dynamic export limit and voltage control are estimated using the Digital Twin, using simulated measurements to address data quality challenges, with results showing curtailment for an exemplar day could be reduced by 56%. Power meter data and a network model are shown to be necessary for developing algorithms that enable decision-making that is robust to real-world uncertainties, with possibilities and challenges of Digital Twin development clearly demonstrated

Primary and secondary power control of multiterminal HVDC grids

Postprint (published version

Backup Protection Algorithm for Failures in Modular DC Circuit Breakers

Funding: 10.13039/100010661-Horizon 2020 Framework ProgrammePeer reviewedPostprin

Analytical model for availability assessment of large-scale offshore wind farms including their collector system

With the increase of offshore wind farm size, the use of classical analytical reliability methods becomes compu-tationally intractable. This paper proposes a holistic approach combining multi-state Markov processes and the universal generating function for the availability assessment of radial large-scale offshore wind farms. The proposed model combines multi-state wind turbine output, wind turbine reliability, and inter-array cable reliability models to assess the wind farm output at the point of common coupling. A strategy is developed to split the network into its feeders while still accounting for the wind turbine output dependence, significantly reducing the computational burden. Although the failure rates of inter-array cables are low, their inclusion is pertinent given high repair times and impact on wind farm output given the radial topology of the collection system. A case study on the Anholt wind farm indicates the necessity of accounting for the collection system, showing a significant reduction of 12 % in generation ratio availability for a generation ratio criterion of 95 %

How to increase cross border transmission capacity? A case study: Belgium.

Cross border capacity allows electric energy to be traded internationally. The electricity sector used to be vertically integrated and often state-owned. High voltage grids were generally developed within the borders of a country. Connecting different national high voltage grids was done to improve the security of the system and to accomodate for a few historical long term contracts. By doing so, the different systems could share their reserve generation capacity. Since the liberalization of the electricity sector, cross border capacity has gained a renewed interest as this can increase the competition in the market. This paper aims to give an overview of recent and planned investments which increase the cross border capacity of Belgium. Also we give an insight into the different technologies which can be used and their advantages and drawbacks are discussed.

Power-System Level Classification of Voltage-Source HVDC Converter Stations Based Upon DC Fault Handling Capabilities

status: publishe