Flexible Transmission: A Comprehensive Review of Concepts, Technologies, and Market

As global concerns regarding climate change are increasing worldwide, the transition towards clean energy sources has accelerated. Accounting for a large share of energy consumption, the electricity sector is experiencing a significant shift towards renewable energy sources. To accommodate this rapid shift, the transmission system requires major upgrades. Although enhancing grid capacity through transmission system expansion is always a solution, this solution is very costly and requires a protracted permitting process. The concept of flexible transmission encompasses a broad range of technologies and market tools that enable effective reconfiguration and manipulation of the power grid for leveraged dispatch of renewable energy resources. The proliferation of such technologies allows for enhanced transfer capability over the current transmission network, thus reducing the need for grid expansion projects. This paper comprehensively reviews flexible transmission technologies and their role in achieving a net-zero carbon emission grid vision. Flexible transmission definitions from different viewpoints are discussed, and mathematical measures to quantify grid flexibility are reviewed. An extensive range of technologies enhancing flexibility across the grid is introduced and explored in detail. The environmental impacts of flexible transmission, including renewable energy utilization and carbon emission reduction, are presented. Finally, market models required for creating proper incentives for the deployment of flexible transmission and regulatory barriers and challenges are discussed

A Review of Economic Incentives for Efficient Operation of Flexible Transmission

The growing penetration of renewable energy requires upgrades to the transmission network to ensure the deliverability of renewable generation. As an efficient alternative to transmission expansion, flexible transmission technologies, whose benefits have been widely studied, can alleviate transmission system congestion and enhance renewable energy integration. However, under the current market structure, investments for these technologies only receive a regulated rate of return, providing little to no incentive for efficient operation. Additionally, a regulated rate of return creates an incentive for building more transmission lines rather than efficient utilization of the existing system. Therefore, investments in flexible transmission technologies remain rather limited. To facilitate the deployment of flexible transmission, improve system efficiency, and accommodate renewable energy integration, a proper incentive structure for flexible transmission technologies, compatible with the current market design, is vital. This paper reviews the current market-based mechanisms for various flexible transmission technologies, including impedance control, dynamic line rating, and transmission switching. This review pinpoints current challenges of the market-based operation of flexible transmission and provides insights for future endeavors in designing efficient price signals for flexible transmission operation.Comment: 2023 55th North American Power Symposium (NAPS

Comparison Of Chloral Hydrate Solution, Hydroxyzine Syrup And Lidocaine/Prilocaine Cream As Premedication For Lumbar Puncture In Children, A Double Blind Study

  ObjectivesThis study aimed to compare the clinical effectiveness of oral hydroxyzine and chloral hydrate to topical lidocaine/prilocaine 2.5% cream as premedication in pediatric leukemia patients. Material & Methods This double-blind clinical trial study was conducted on 70 leukemic and non-leukemic patients aged 3-11 years old. The patients were divided into 4 groups as follow: in the group A, choral hydrate solution was given in 18 patients, in group B hydroxyzine syrup was used in the same number of patients, in group C, chloral hydrate solution and Lidocaine/Prilocaine cream were used in 17 patients, and in group D hydroxyzine syrup and Lidocaine/Prilocaine cream were given in the same number of patients. These groups were assessed and judged based on visual analog scale (VAS). Side effects of the drugs were also recorded. Results In this study, 54.3% (38) of cases were girls and 45.7% (32) were boys. Patients’ selection was included as follow: ALL in 77%, AML in 7.2% and non-leukemic cases in 15.8% of cases. The VAS test showed no difference in these four groups. Non-Traumatic lumbar puncture (RBC<50) were seen in 97.1% of cases. Conclusion Although the use of pre-medications for lumbar puncture with hydroxyzine syrup and chloral hydrate solution was not statistically effective, it did lead to increased patient and parent satisfaction. Also, adding  the Lidocaine/Prilocane cream does not improve the effectiveness of the drugs. &nbsp

An aggregator-based dynamic pricing mechanism and optimal scheduling scheme for the electric vehicle charging

High penetration of electric vehicles (EVs) in an uncontrolled manner could have disruptive impacts on the power grid, however, such impacts could be mitigated through an EV demand response program. The successful implementation of an efficient, effective, and aggregated demand response from EV charging depends on the incentive pricing mechanism and the load shifting protocols. In this study, a genetic algorithm-based multi-objective optimization model is developed to generate hourly dynamic Time-of-Use electricity tariffs and facilitate the decision making in load scheduling. As an illustrative example, a case study was carried out to examine the effect of applying demand response for EVs in Beijing, China. With the assumptions made, the maximum peak load can be reduced by 9.8% and the maximum customer savings for the EVs owners can reach 11.85%, compared to the business-as-usual case