Jake P. Gentle

A Comparison of Real-Time Thermal Rating Systems in the U.S. and the U.K.

Real-time thermal rating is a smart-grid technology that allows the rating of electrical conductors to be increased based on local weather conditions. Overhead lines are conventionally given a conservative, constant seasonal rating based on seasonal and regional worst case scenarios rather than actual, say, local hourly weather predictions. This paper provides a report of two pioneering schemes-one in the U.S. and one in the U.K.-where real-time thermal ratings have been applied. Thereby, we demonstrate that observing the local weather conditions in real time leads to additional capacity and safer operation. Second, we critically compare both approaches and discuss their limitations. In doing so, we arrive at novel insights which will inform and improve future real-time thermal rating projects.

Dynamic Line Rating systems: Research and policy evaluation

Dynamic Line Rating (DLR) is a smart grid technology that allows the rating of electrical conductors to be increased based on local weather conditions. Overhead lines are conventionally given a conservative rating based on worst case scenarios. We demonstrate that observing the conditions in real time leads to additional capacity and safer operation. This paper provides a report of a pioneering scheme in the United States of America in which DLR has been applied. Thereby, we demonstrate that observing the local weather conditions in real time leads to additional capacity and safer operation. Secondly, we discuss limitations involved. In doing so, we arrive at novel insights which will inform and improve future DLR projects. Third, we provide a policy background and discussion to clarify the technologys potential and identifies barriers to the imminent adoption of dynamic line rating systems. We provide suggestions for regulatory bodies about possible improvements in policy to encourage adoption of this beneficial technology.

Active control of thermostatic loads for economic and technical support to distribution grids

Active control of electric water heaters (EWHs) is presented in this paper as a means of exploiting demand flexibility for supporting low-voltage (LV) distribution grids. A single-node model of an EWH is implemented in DIgSILENT PowerFactory using a thermal energy balancing equation and three decentralized control schemes are designed to ensure consumer comfort, economic benefit to the consumer, and technical support to LV grids. First, a price-based control that adaptively adjusts an allowable energy band per electricity price is implemented to ensure economic benefit. Next, an adaptive update of the energy band is done based on feeder loading to respect thermal grid constraints. Finally, a voltage-based control is implemented to provide real-time voltage support to the LV grids. Simulation results demonstrate the capability of the presented method to realize both economic and technical advantages. For the given configuration and pricing scheme, EWH owners are able to decrease their electricity cost by 29.33%, along with simultaneous assurance of consumer comfort and grid constraints.

INVESTIGATION OF A DYNAMIC POWER LINE RATING CONCEPT FOR IMPROVED WIND ENERGY INTEGRATION OVER COMPLEX TERRAIN

Dynamic Line Rating (DLR) is a smart grid technology that allows the rating of power line to be based on real-time conductor temperature dependent on local weather conditions. In current practice overhead power lines are generally given a conservative rating based on worst case weather conditions. Using historical weather data collected over a test bed area, we demonstrate there is often additional transmission capacity not being utilized with the current static rating practice. We investigate a new dynamic line rating methodology using computational fluid dynamics (CFD) to determine wind conditions along transmission lines at dense intervals. Simulated results are used to determine conductor temperature by calculating the transient thermal response of the conductor under variable environmental conditions. In calculating the conductor temperature, we use both a calculation with steady-state assumption and a transient calculation. Under low wind conditions, steady-state assumption predicts higher conductor temperatures that could lead to curtailments, whereas transient calculations produce conductor temperatures that are significantly lower, implying the availability of additional transmission capacity.

Operators Working with Transmission Flexibility: Enhancing Utility Control Rooms with Dynamic Line Rating Technique

This paper reflects generally on the human factors approach of integrating the Dynamic Line Rating (DLR) technique into power utilities control room as well as other monitoring systems, investigates how to accommodate transmission operators’ needs and incorporate the new technology into a control room regarding these needs.