Search results for "Thermal rating"
showing 7 items of 7 documents
The effect of the axial heat transfer on space charge accumulation phenomena in HVDC cables
2020
To date, it has been widespread accepted that the presence of space charge within the dielectric of high voltage direct current (HVDC) cables is one of the most relevant issues that limits the growing diffusion of this technology and its use at higher voltages. One of the reasons that leads to the establishment of space charge within the insulation of cables is the temperature dependence of its conductivity. Many researchers have demonstrated that high temperature drop over the insulation layer can lead to the reversal of the electric field profile. In certain conditions, this can over-stress the insulation during polarity reversal (PR) and transient over voltages (TOV) events accelerating …
Uprating an Overhead Line. Italian TSO Applications for Integration of RES
2013
The increase of Renewable Energy Sources (RES) production units has caused significant changes in the electrical system configuration. The existing structural asset isn't adequate to dispatch these new power flows that, at same time, should be favorite by various TSOs in order to obtain incentives. The outage of primary substations on the grid and the increase of consumptions have caused growing load currents on existing overhead line. This paper, after introducing thermal resistant conductors and Dynamic Rating (DR) solutions, reports an applications used by TERNA Group S.p.A. (Italian TSO). These systems are already installed on lines and they are contributing to increase power flows than…
Effect of Heat Exchange Transient Conditions with Moving Water-Air Interface on Space Charge Accumulation in Undersea HVdc Cables
2021
The accumulation of space charge inside the dielectric layer of an HVdc cable is one of the most important issue to be considered in the design stage and during the operating conditions. The separation of space charge is due to several factors including the dependence on temperature of the electrical conductivity of the insulation and the establishment of a thermal gradient under load conditions. This article is focused on the investigation of the effect of an axial heat transmission on the space charge and electric field distributions in an HVdc cable. In order to assess the impact of this phenomenon, a case study involving a cable immersed partly in water and partly in air has been simula…
A Power Sector in Transition Understanding Transition Towards a Cleaner Grid and how Distributed Energy Resources Affect the Design and Operation of …
2018
Important changes in the supply and the demand side of electricity apparatus are now underway, triggered by a combination of drivers dramatically affecting the transmission sector of power systems: greenhouse gas emissions, distributed generation, energy efficiency and the full integration of the European energy market. A variety of accelerating factors - including active consumer, aggregators, energy storage, e-vehicles, etc..- are creating a new era for the many stakeholders, incl. system operators, regional entities, industry and consumer organizations, producers or their trade bodies, Regulators, public decision makers and the society at large. Entraining this background, ENTSO-E and th…
Methodologies to uprate an overhead line. Italian TSO case study
2013
The amount of wind power and other time-variable non-dispatchable electricity generation is rapidly increasing across the world, causing a significant change in the electrical system configuration. The existing structural asset isn't adequate to dispatch these new power that have a priority in the energy dispatching. In addiction the outage of substations on the grid and the increase of consumptions have caused growing load currents. In order to satisfy these needs, TSOs have adopted new measures on existing power lines and N-1 criteria to ensures the electrical grid security. These particular devices are Dynamic Thermal Rating (DTR) systems. After introducing thermal resistant conductors a…
Uprating an overhead line. Italian TSO applications to increase system N-1 security
2013
This paper analyzes innovative devices to optimize the energy flows transmission on existing overhead lines. Indeed sometimes the structural asset isn’t adequate to manage energy generated by Renewable Energy Source (RES) in particular operating conditions. In addiction the outage of primary substations on the grid and the increase of consumptions have caused growing load currents. In order to satisfy these needs, TSOs have adopted new measures on existing power lines and N-1 criteria to ensures the electrical grid security. These particular devices are Dynamic Rating systems. After introducing thermal resistant conductors and Dynamic Rating (DR) solutions, paper reports two different appli…
Dynamic thermal rating for overhead lines: Self-adaptive protection device
2013
The increase in the consumption of electricity, the stringent environmental restrictions and the need to keep costs, make ever more meaningful the need for a flexible operation of existing overhead lines. This paper studies the possibility to use a dynamic thermal rating for overhead line starting from the analysis of the mathematical model and the ability of the latter to reflect the temperature of an overhead conductor in different ambient condition; then it simulates the thermal behaviour of a conductor both in steady state and dynamic one. Finally the paper shows a method for a self-adaptive thermal protection system.