Impacts of harmonic distortion from charging electric vehicles on low voltage networks

Paper focusing on the impacts of harmonic distortion from charging electric vehicles on low voltage networks

Designing Wind Turbine Condition Monitoring Systems Suitable for Harsh Environments

Research into wind turbine condition monitoring is continually receiving greater attention due to the potential benefits from condition monitoring systems (CMS). These benefits can only be realised with high reliability of the condition monitoring system itself. This paper discusses how CMS reliability can be increased, by introducing four types of robustness and how to design the CMS to meet these requirements. The paper uses a case study CMS installation to illustrate the design requirements, and lessons learned from the installation process

Modelling, analysis and verification of a resonant llc converter as a power supply for the electromagnetic driving mechanism of an electromagnetic contactor

The paper presents model based analysis and experimental verification of a half-bridge resonant LLC converter for suppling power to the electromagnetic driving mechanism of an electromagnetic contactor. In the proposed application the convertor - powered either by AC or DC voltage - supplies the coil of the contactor with DC voltage. Analytical and experimental results presented, show several important advantages of the proposed topology: versatility in terms of input voltages – both AC and DC are accepted; stability over wide voltage range; omission of overvoltages – common to electromagnetic systems; reduced power consumption

Dispatch of vehicle-to-grid battery storage using an analytic hierarchy process

The number of electric vehicles (EVs) is expected to increase significantly in the future to combat air pollution and reduce reliance on fossil fuels. This will impact on the power system. However, appropriate charging and discharging of EVs through vehicle-to-grid operations could also provide support for the power system and benefits for the EV owners. This raises the questions of when and how EV battery storage should be dispatched, taking into account both vehicle users’ and power system’s requirements and priorities, as well as the constraints of the battery system. This paper proposes a novel decentralized dispatch strategy based on the Analytic Hierarchy Process (AHP) taking into account the relative importance of the different criteria including cost, battery state of charge, power system contingency and load levelling. The proposed AHP-based dispatch strategy was tested on an IEEE Reliability Test System with different EV numbers and capacities to investigate the efficacy of such an approach. The simulation results demonstrate the feasibility and benefits of this dispatch strategy

Demand side management of electric vehicle car parks to increase integrated solar power capacity within an existing radial distribution network

The amount of integrated solar power generation capacity within the UK distribution networks is expected to continue to increase within the next few years. However, the grid has a fixed power transfer capacity, and to avoid the extra cost of power system upgrade or curtailment of renewable power, it would be necessary to store the surplus power from such non-dispatchable renewable resources using appropriate energy storage technologies. In this work, a novel control strategy based on extended optimal power flow is introduced to control the charging of electric vehicles located at car parks to increase the solar power generation capacity within a radial distribution network while satisfying the power system constraints and electric vehicle user requirements

Improvement of power system frequency stability using alkaline electrolysis plants

Hydrogen could become an important energy carrier, in particular used as an input to fuel cell electric vehicles. Alkaline electrolysers are an attractive technology to produce carbon-free hydrogen from renewable generated electricity. Large-scale alkaline electrolysers used in future hydrogen-filling stations could also be utilised to improve the frequency stability of the electricity power system. The electrolyser load can be controlled to respond to power system frequency variations, and in the case of a sudden loss of generation, these electrolysers could rapidly decrease their load on the system to maintain the power balance. In this study, the potential of alkaline electrolysers to dynamically stabilise the frequency of the power system is assessed. A model of steam turbine generation unit has been developed in MATLAB SIMULINK environment, and a scenario in which there is a sudden loss of generation in the system is examined. It is demonstrated that alkaline electrolysers could prevent unacceptable frequency drop, i.e. below the statutory limit, following by an abrupt loss of generation, even with no spinning reserve on the system. In this article for the first time, the ramping rate of an alkaline electrolyser is shown through experimental data. <br/

Pseudo-Code and Data Appendices for Paper: A Technique to Interconnect and Control Co-Simulation Systems

Appendices for IET paper: A Technique to Interconnect and Control Co-Simulation Systems. Assigned DOI: 10.5258/SOTON/405667</span

Analysis, Design and Experimental Validation of a Primary Side Current Sensing Flyback Converter for Use in a Battery Management System

The purpose of the presented flyback converter is to equalise the voltage between the cells in a series string within a battery pack providing an active cell-balancing system. This would be an important part of a battery management system (BMS) for charging li-ion batteries in electric vehicles. The converter is based on primary side current sensing, where the conventional feedback circuit is omitted. The purpose of this converter is to improve efficiency by decreasing losses and to increase battery power density by decreasing the number of elements which constitute the power electronics; these are important factors for the future development of electric vehicle battery packs. Analysis of the circuit and the design procedure of the DC-DC flyback converter with primary current sensing is presented in this paper. Finally, several experimental converters have been built and tested to validate the authors’ approach

Analytical Predictions for a Natural Spacing within Dyke Swarms

International audienceDykes often grow next to other dykes, evidenced by the widespread occurrence of dyke swarms that comprise many closely-spaced dykes. In giant dyke swarms, dykes are observed to maintain a finite spacing from their neighbors that is tens to hundreds of times smaller than their length. To date, mechanical models have not been able to clarify whether there exists an optimum, or natural spacing between the dykes. And yet, the existence of a natural spacing is at the heart of why dykes grow in swarms in the first place. Here we present and examine a mechanical model for the horizontal propagation of multiple, closely-spaced blade-like dykes in order to find energetically optimal dyke spacings associated with both constant pressure and constant influx magma sources. We show that the constant pressure source leads to an optimal spacing that is equal to the height of the blade-like dykes. We also show that the constant influx source leads to two candidates for an optimal spacing, one which is expected to be around 0.3 times the dyke height and the other which is expected to be around 2.5 times the dyke height. Comparison with measurements from dyke swarms in Iceland and Canada lend initial support to our predictions, and we conclude that dyke swarms are indeed expected to have a natural spacing between first generation dykes and that this spacing scales with, and is on the order of, the height of the blade-like dykes that comprise the swarm

Utilisation of alkaline electrolysers in existing distribution networks to increase the amount of integrated wind capacity

Hydrogen could become a significant fuel in the future especially within the transportation sector. Alkaline electrolysers supplied with power from renewable energy sources could be utilised to provide carbon free hydrogen for future hydrogen filling stations supplying Hydrogen Fuel Cell Vehicles (HFCV), or Internal Combustion Engines (ICEs) modified to burn hydrogen. However, there is a need to develop and use appropriate strategies such that the technology delivers greater economic and environmental benefits