An auction framework to integrate dynamic transmission expansion planning and pay-as-bid wind connection auctions. ESRI WP523. January 2016

Efficient renewables deployment requires the minimisation of both internal generation costs and external transmission expansion planning (TEP) costs. Competitive pay- as-bid connection auctions allow wind energy generators to reveal their costs of generation such that internal generation costs may be minimised. TEP costs have not been incorporated into such auctions to date. Integrating these procedures may allow for a global minimisation of internal generation and external TEP costs over many time periods. This paper develops an auction mechanism and associated modelling framework to carry this out. The contributions of this framework are verified using a numerical example. Our results show that ignoring generation costs in transmission expansion planning has quantifiable economic consequences, while traditional pay-as-bid auctions can benefit from incorporating features associated with TEP, such as multi-period optimisation. Full integration of both modelling frameworks leads to efficiency improvements, both in terms of reduced investor rent-seeking and a more efficient deployment path

Fast Resource Scheduling for Distribution Systems Enabled with Discrete Control Devices

This paper proposes a framework for fast short-term scheduling and steady-state voltage control in distribution systems enabled with both continuous control devices, e.g., inverter interfaced DGs and discrete control devices (dcds), e.g., on-load tap changers (oltcs). The voltage-dependent nature of loads is taken into account to further reduce the operating cost by managing the voltage levels. The branch and cut method is applied to handle the integrality constraints associated with the operation of dcds. A globally convergent trust-region algorithm (tra) is applied to solve the integer relaxed problems at each node during the branching process. The tra sub-problems are solved using the interior point method. To reduce the branching burden of the branch and cut algorithm, before applying tra at each node, a simplified optimization problem is first solved. Using the convergence status and value of the objective function of this problem, a faster decision is made on stopping the regarding branch. Solving the simplified problem obviates the application of tra at most nodes. It is shown that the method converges to the optimal solution with a considerable saving in computation time according to the numerical studies

Power to air transportation via hydrogen

This study proposes a framework to analyse the concept of power to hydrogen (P2H) for fuelling the next generation of aircraft. The impact of introducing new P2H loads is investigated from different aspects namely, cost, carbon emission, and wind curtailment. The newly introduced electric load is calculated based on the idea of replacing the busiest international flight route in the Europe, Dublin‐London Heathrow, by hydrogen fuel‐powered aircraft as a high potential candidate for the next generation of air travel systems to cope with the ambitious targets set in Europe Flight Path 2050 by the Advisory Council for Aeronautics Research in Europe. The simulation is performed on a representative Irish transmission network to demonstrate the effectiveness of the proposed solution

Optimal Deployment of Mobile MSSSC in Transmission System

With the rapid development of the renewable energy source (RES), network congestion management is increasingly important for transmission system operators (TSOs). The limited transmission network capacity and traditional intervention methods result in high RES curtailment. The near-term, powerful, and flexible solutions, such as advanced flexible AC transmission systems (FACTS), are considered to mitigate the risks. The mobile modular static synchronous series compensator (MSSSC) is one of the grid-enhancing solutions. The mobility of the solution allows it to offer fast deployment and seasonal redeployability with limited cost. The demonstration of the mobile MSSSC solution has shown significant benefits for RES curtailment reduction, network congestion alleviation, and facilitating the demand and RES connection. For unlocking the true value of the mobile solution, they should be optimally allocated in the transmission networks. This paper develops a security-constrained DCOPF-based optimisation tool to investigate the optimal allocation of the mobile MSSSC solution in transmission networks. A linear mobile MSSSC model with the operation dead-band was introduced that can be used in large-scale realistic power system planning. The proposed model was implemented in the IEEE 118-bus system to assess the performance of the mobile MSSSC.University College Dubli

Optimising Load Flexibility for the Day Ahead in Distribution Networks with Photovoltaics

This paper has been presented at: 2019 IEEE Milan PowerTechIn this paper a methodology is proposed to calculate the load demand flexibility that could be activated within the next 24-hours for solving the technical impacts of contingencies that may come up in an unbalanced low voltage distribution networks with high penetration of intermittent DG sources. The methodology is formulated within a Demand Response program environment via load shifting as flexibility enabler mechanism. To achieve that, a non-linear optimisation problem is formulated based on an unbalanced optimal power flow, which allows the determination of the load flexibility that each Demand Response customer could provide at the request of the Distribution System Operator. The demand as well as weather conditions are forecasted for the day ahead. The optimisation problem is solved in a sequence fashion, within a daily framework, splitting the whole problem in optimisation blocks. In each block, the flexible load demand is obtained and the load demand forecasting its updated for the upcoming blocks based on the changes in the scheduled load demand. The methodology is applied to a real distribution network with the load data received from the smart metering infrastructure. The results obtained show the strength of the methodology in solving the technical problems of the network under high unbalanced operation.The work done by Valentin Rigoni and Alireza Soroudi is supported by a research grant from Science Foundation Ireland (SFI) under the SFI Strategic Partnership Programme Grant No. SF/15/SPP/E3125. The opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Science Foundation Ireland. Jose Angel Velasco and Hortensia Amaris are supported by the Spanish Ministry of Economy and Competitiveness through the National Program for Research under the project OSIRIS (RTC-2014-1556-3)

Effect of Composite Color and Thickness on Correction of Tooth Discoloration

Objective: Selection of an appropriate shade of composite is critical in achieving an esthetic restoration. Different systems are used to assess and describe color parameters. This study aimed to assess the effect of color and thickness of Filtek Supreme (FS) and Premise (P) composite resins on correction of tooth discoloration.Methods: In this in vitro experimental study, 10 anterior teeth with Vita A2 color shade were selected. Composite specimens were fabricated in 0.5 and 0.75 mm thicknesses of FS and P composites. Intact teeth, prepared teeth, prepared teeth with enamel and dentin composite discs on their buccal surfaces, stained teeth and stained teeth with composite discs were photographed using a digital camera under standard conditions and color change (ΔE) at different phases was calculated.Results: The L*, a* and b* color parameters in prepared and unstained teeth were not significantly different from those of intact teeth. In stained teeth, the L* parameter only in prepared and stained teeth with 0.75mm P composite was not significantly different from the L* parameter in intact teeth. Significant differences were seen in other stained teeth. The a* and b* parameters only in prepared and stained teeth with 0.5 mm FS composite were significantly different from those in intact teeth. By increasing the thickness of composite, the color change in comparison with intact teeth decreased in both groups.Conclusion: The results showed that the effect of type of composite, its thickness and their interaction on the color change was significant when using FS and P composites in 0.5 and 0.75mm thicknesses in comparison to intact teeth and the lowest color difference with intact teeth was achieved using 0.75mm thickness of P composite (enamel and dentin)

PMU-OBI : Maximizing the network observability using a limited number of PMU for IEEE 14 network without considering zero injection nodes

For more details please refer to Chapter 8 (Gcode8.4), of the following book: Soroudi, Alireza. Power System Optimization Modeling in GAMS. Springer, 2017. This chapter provides a solution for increasing the power system observability by allocation of Phasor Measurement Units (PMU) problem in GAMS