This paper aims to demonstrate the performance and reliability analysis of a dynamic line rating (DLR) system at the Bulgarian demonstration site of the FLEXITRANSTORE project. As part of the project, various manufacturers’ different line monitoring DLR sensors and weather stations were installed on a 110 kV double-circuit overhead line (OHL). These devices provided input parameters to the DLR system based on objective measurements. This paper used statistical tools to examine the reliability and accuracy of installed devices, thus making products from different manufacturers comparable. In addition, two independent line monitoring and DLR models have been developed: the black-box and extended white-box models. The performances of the two models were analyzed for the same input parameters and compared to the field measurements. Based on the presented results, the reliability and accuracy of the applied weather stations of different companies were almost the same. This conclusion cannot be said for DLR line monitoring sensors, where the devices could be differentiated based on reliability and measurement accuracy results. In terms of models, the usability of the extended white-box model seemed to be limited in certain weather conditions, implicating a more significant role for soft-computing-based DLR models in the future. In addition to the results, root causes for the errors and future directions that may provide a framework for further research are also presented.

In case of transmission and distribution networks, extra low frequency (typically 50 or 60 Hz) electric and magnetic fields have to be taken into consideration separately from each other. Health effects have been documented from exposures to both types of fields. Magnetic fields are qualified as possibly carcinogenic to humans (category "2B") by WHO's cancer research institute, International Agency for Research on Cancer (IARC), so it is essential to protect the workers against their harmful effects. During live-line maintenance (LLM) electric fields can be shielded effectively by different kinds of conductive clothing, which are enclosed metal surfaces acting as a Faraday-cage. In practice laboratory measurements also prove their efficiency, the required shielding ratio is above 99% by the related standard.. A set of measurements have proved that regular conductive clothing used against the electric fields cannot shield the magnetic fields effectively at all. This paper introduces the possible risks of LLM from the aspect of the health effects of magnetic fields. Although in this case the principle of shielding the electric fields cannot be applied, new considerations in equipment design and technology can be used as a possible solution. Calculations and simulations based on the data of the Hungarian transmission network - which represents the European grid as a part of ENTSO-E - and high-current laboratory measurement results also prove the importance of the topic.

Hungary was one of the pioneers of high voltage live-line maintenance in the 1960s. Many of the currently applied technologies and equipment is related to the developments of Dr. Béla Csikós, one of the pioneers of this technology. Nowadays different working methods are used worldwide for the maintenance of the energized components of the high voltage grid. As a part of an international project, Budapest University of Technology and Economics is involved in the improvement of existing live-line activities in the Hungarian high voltage grid. This paper introduces the research and development of composite insulator changing method in the vicinity of both energized and grounded parts in the Hungarian grid. There is also a need to introduce the safe approach technology for conductors above the lowest phase which only can currently been reached by the existing techniques. As the result of a co-operation between the Hungarian TSO and the High Voltage Laboratory of Budapest University of Technology and Economics, newly developed technologies will be introduced in the live grid to demonstrate the new capabilities. These new developments are proposed to increase the efficiency of live-line works by the increment of activities executable while the grid is energized. Besides the technical and economic benefits, with proper risk assessment the safety of the workers may be increased as well, compared to the de-energized works.