Risk Of Thermal Overload Research Articles

Review of magnetic islands from the divertor perspective and a simplified heat transport model for the island divertor

Magnetic islands in toroidal confinement devices are reviewed from the viewpoint of their divertor potential. Divertor-relevant geometric parameters are derived analytically, and the relationships among them are revealed. We explain how the island geometry limits the target length and demonstrate the importance of an appropriate numerical tool to minimize the risk of thermal overload of plasma-facing components in the divertor design. The currently available three-dimensional (3D) models are briefly discussed, and their strengths and weaknesses are evaluated. The highlight will be the introduction of a new energy transport model recently developed within the framework of the EMC3 code (Feng et al 2004 Contrib. Plasma Phys. 44 57)—the so-called EMC3-Lite version—primarily for the design and optimization of 3D divertors involving thermal overload concerns. While still undergoing experimental validation with the current graphite divertor of W7-X, it is already being used to develop a subsequent tungsten divertor for W7-X.

Real-Time Transient Thermal Rating and the Calculation of Risk Level of Transmission Lines

With the increasing consumption of electric energy, how to improve the capacity of transmission lines within safe margins is an urgent problem to be solved. This paper presents a transient thermal rating method under real-time meteorological conditions. The result of thermal ratings under different conditions shows that this rating approach can significantly increase the capacity of the line. As some of the most critical variables are remaining time and initial temperature, their influence upon the rating is studied. The method of statistical analysis is used to determine the ampacity at different risk levels. The result indicates that with smaller remaining time, the ampacities are larger, and with larger ampacities, the risk of thermal overload is greater. The choice of risk level would heavily affect the values of ampacity.

A Bayesian approach for short-term transmission line thermal overload risk assessment

An on-line conductor thermal overload risk assessment method is presented in this paper. Bayesian time series models are used to model weather conditions along the transmission lines. An estimate of the thermal overload risk is obtained by Monte Carlo (MC) simulation. We predict the thermal overload risk for the next hour based on the current weather conditions and power system operating conditions. The predicted risk of thermal overload is useful for on-line decision making in a stressed operational environment.

A Bayesian Approach for Short-Term Transmission Line Thermal Overload Risk Assessment

An online conductor thermal overload risk assessment method is presented. Bayesian time-series models are used to model weather conditions along the transmission lines. An estimate of the thermal overload risk is obtained by Monte Carlo simulation. We predict the thermal overload risk for the next hour based on the current weather conditions and power system operating conditions. The predicted risk of thermal overload is useful for online decision-making in a stressed operational environment.

Increasing thermal rating by risk analysis

It has long been realized that the thermal ratings of overhead transmission lines when computed deterministically, are typically conservative, resulting in under-utilization of conductors. A probabilistic method to assess thermal capacity based on risk is presented in this paper. The authors address the potential impacts of thermal overload, the stochastic model of conductor temperature, and the quantitative risk which indicates the average "danger" of an overload. The continuous, short-time and long-time thermal ratings are calculated using the risk of thermal overload. This method can provide technical justification for increased thermal capacity for a transmission line and an evaluation of risk for the given operating conditions.