Real-time power line rating may be provided. First, sensor data may be received corresponding to a conductor of a power line. The sensor data may provide real-time weather conditions for the conductor's environment. The sensor data may be received from a sensor device configured to collect the sensor data. The sensor data may correspond to the weather conditions at a location of the sensor device on the power line. Next, design limitations for the power line having the conductor may be received. The conductor of the power line may have a design ampacity based upon the design limitations and assumed weather conditions for the conductor's environment. Then a dynamic ampacity may be calculated for the power line based upon the received sensor data and the received design limitations for the power line. The power line may then be operated according to the calculated dynamic ampacity instead of the design ampacity.

Real-time power line rating

ANSI standards for power equipment, and a vast store of technical literature, describe various methods by which thermal ratings may be adjusted if actual weather conditions are known or if the "overload" is to be applied for a limited period of time. These methods have been given various names including dynamic thermal rating, on-line rating, and dynamic ratings to describe the process of adjusting thermal ratings of power equipment for actual weather conditions and actual electrical load patterns. This paper discusses in detail a project undertaken by the Electric Power Research Institute (RP 3022-7) as part of its research on Flexible AC Transmission. This project avoids dependence on temperature measurement, instead, calculating critical equipment component temperatures based solely on real-time weather and electrical current. Inexpensive, commercially available weather stations, digital data loggers, and IBM-compatible PC computers are combined with sophisticated thermal algorithms to yield a portable, flexible, instrumentation method which can rate several transmission circuits simultaneously, including underground cable, overhead lines, power transformers, current transformers, switches, bus, line traps, and circuit breakers. Useable increases of 5% to 15% in the thermal capacity of transmission equipment circuits result.

Real-time monitoring and dynamic thermal rating of power transmission circuits

Power Line Sensor Networks for Enhancing Power Line Reliability and Utilization

This paper presents an overview of the state of the art on the research on Dynamic Line Rating forecasting. It is directed at researchers and decision-makers in the renewable energy and smart grids domain, and in particular at members of both the power system and meteorological community. Its aim is to explain the details of one aspect of the complex interconnection between the environment and power systems. The ampacity of a conductor is defined as the maximum constant current which will meet the design, security and safety criteria of a particular line on which the conductor is used. Dynamic Line Rating (DLR) is a technology used to dynamically increase the ampacity of electric overhead transmission lines. It is based on the observation that the ampacity of an overhead line is determined by its ability to dissipate into the environment the heat produced by Joule effect. This in turn is dependent on environmental conditions such as the value of ambient temperature, solar radiation, and wind speed and direction. Currently, conservative static seasonal estimations of meteorological values are used to determine ampacity. In a DLR framework, the ampacity is estimated in real time or quasi-real time using sensors on the line that measure conductor temperature, tension, sag or environmental parameters such as wind speed and air temperature. Because of the conservative assumptions used to calculate static seasonal ampacity limits and the variability of weather parameters, DLRs are considerably higher than static seasonal ratings. The latent transmission capacity made available by DLRs means the operation time of equipment can be extended, especially in the current power system scenario, where power injections from Intermittent Renewable Sources (IRS) put stress on the existing infrastructure. DLR can represent a solution for accommodating higher renewable production whilst minimizing or postponing network reinforcements. On the other hand, the variability of DLR with respect to static seasonal ratings makes it particularly difficult to exploit, which explains the slow take-up rate of this technology. In order to facilitate the integration of DLR into power system operations, research has been launched into DLR forecasting, following a similar avenue to IRS production forecasting, i.e. based on a mix of statistical methods and meteorological forecasts. The development of reliable DLR forecasts will no doubt be seen as a necessary step for integrating DLR into power system management and reaping the expected benefits.

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Forecasting for dynamic line rating

Electrical networks across the globe are gearing towards environmentally friendly operation with many renewable sources being introduced. Among them, the popularity of electrical generation by wind has gained the most ground. Wind, as one of the meteorological conditions, also has high influence on line ratings and such manner of operating the line is known as dynamic thermal rating (DTR) system. Seeing this relationship, it is intuitively important to investigate the reliability of a electrical network incorporating DTR and wind farm. Hence, the objective of this paper is to propose a methodology that can perform this task. In the methodology, sequential Monte Carlo (SMC) simulation was performed due to time dependencies of line ratings and wind power. As a result, modeling of these time-series data was performed using the auto-regressive and moving-average (ARMA) model. Moreover, correlations between line rating and wind power were also considered to provide a practical approach to the modeling. Results have shown that DTR system is able to increase network reliability and allows for higher wind energy penetration.

/pdf/reliability-impact-of-dynamic-thermal-rating-system-in-wind-4spj428b60.pdf

Reliability Impact of Dynamic Thermal Rating System in Wind Power Integrated Network

For the first time a Real Time Thermal Rating System has been developed for overhead transmission lines using actual meteorological data and real-time conductor temperatures and line loadings. This System provides, on a probability basis, much higher ampacity ratings than those derived from conventional methods. As a portion of this System, a steady state thermal rating procedure is presented in the companion paper, which includes forced convection heat transfer equations taking into account the effect of wind turbulence or gustiness, conductor yaw (wind direction), conductor height above ground, smooth versus rough (stranded) conductor surfaces, the proximity of conductors in a bundle, and conductor pitch. A natural convective heat equation is developed for stranded conductors. The conductor temperature is solved directly without resorting to an iterative solution.

A new thermal rating approach: The real time thermal rating system for strategic overhead conductor transmission lines -- Part I: General description and justification of the real time thermal rating system

M.W. Davis

Papers

A new thermal rating approach: The real time thermal rating system for strategic overhead conductor transmission lines -- Part I: General description and justification of the real time thermal rating system