Dynamic thermal rating in icing conditions

In February 2014 a severe icing storm hit Slovenia, and caused damage in order of 8.5 million € only on the power transmission network. A feasibility study performed by Jožef Stefan Institute (JSI), Milan Vidmar Electric Power Research Institute (EIMV), Slovenian Environment Agency (SEA), and Slovenian Electricity Transmission System Operator (ELES) confirmed that using Joule heating could prevent icing in similar conditions. Based on the results JSI, during the TTP, further developed an operative software termed DTRi (Dynamic Thermal Rating - icing). The core of the DTRi is a physical model for the simulation of heat transfer within the transmission power line under realistic weather conditions related to the icing, i.e., ambient temperatures between -5°C and 5°C with super cooled rain present. The DTRi comprises the Joule heating, convection, solar heating, evaporation, radiation and impinging super cooled precipitation. Basically, the DTRi solves the heat transport equation (second order partial differential equation) with non-linear boundary conditions describing different heat terms due to the weather conditions (Figure 1). The results obtained with DTRi have been compared against available published data as well as measurements provided by EIMV, with promising results.

DTRi can run in two modes, i.e. as standalone software and as an embedded system within the SUMO framework, which is a heterogeneous collection of subsystem from different vendors that was developed to increase safety and security as well as the capacity of the existing transmission network. Its core is the integration platform, SUMO BUS, which is an enterprise integration bus, used for orchestrating the subsystems and facilitating data exchange between them. The communication between SUMO BUS and the subsystems is based on web services. More precisely subsystems communicate with the bus via SOAP/HTTP interfaces. This technology enables different subsystem vendors to quickly and efficiently connect their subsystems using standardized and open means of communication and exchanging data. For example, SUMO allows different Dynamic Thermal Rating (DTR) vendors to be incorporated into the system, each serving a different part of the grid. Currently there are 17 services implemented. They are providing approximately 115 methods to the clients (subsystems). System’s internal state is held in a relational SQL database.

Project plan: available here.

Project description in Slovene language

Februarja 2014 je Slovenijo prizadel hud žledolom, ki je samo na prenosnem energetskem omrežju povzročil škodo velikostnega reda 8 milijonov €. Skupaj z raziskovalnimi sodelavci z Inštituta Milan Vidmar in Agencije RS za okolje smo razvili in preizkusili model DTRi (Dynamic Thermal Rating - icing), na podlagi katerega smo zasnovali prototipni sistem za operativno napovedovanje in preprečevanje nastajanja žleda na visokonapetostnih vodnikih. Prototipni sistem smo validirali preko meritev na testnem poligonu in preko rekonstrukcije dveh realnih primerov, in sicer 1.2.2014 ter 5.1.2016 na trasi Beričevo-Divača. Rezultati študije so obetajoči, zato se je naročnik odločil, da sistem DTRi postavi tudi v operativno okolje SUMO. V ta namen smo pridobili dodatna sredstva iz EU FP7 projekta TETRACOM. Oba projekta vodijo člani naše programske skupine, naročnik del pa je družba ELES.

Contact information


Jozef Stefan Institute is the leading Slovenian scientific research institute, covering a broad spectrum of basic and applied research. The staff of more than 960 specializes in natural sciences, life sciences and engineering.


The ELES Company ensures the safe, reliable and uninterrupted transmission of electricity. ELES is the guardian of Slovenia’s electric power transmission system, which is closely connected to the transmission networks of neighbouring countries and integrated into the European energy system.


Elektroinštitut Milan Vidmar (EIMV) is the leading Slovenian engineering and scientific research organisation acting in the area of electric power engineering and was established in 1948. From the economic and technological perspective, it addresses the issues of generation, transmission and distribution of electricity.


The project is funded by:

and has a total amount of 195 000 Euro -- 70 000 Euro for the technology transfer and 125 000 Euro for the feasibility study.


The following documents (papers, conference papers, manuals, ...) were produced with financing from this project




Simulation results

simulation results

Sumo interface

sumo interface

Alarm response

alarm response