Zofia Wróbel

The railway transport system is a key factor supporting industrialization in all aspects of human activity. However, in order not to lose its importance, it must meet the challenge of modern civilization. The safety, reliability, and efficiency of railway transport, to a large degree, depend on using highly integrated electronics, which are very sensitive to various disturbances generated in the electric traction system and train or coming from the environment. One of the sources of electromagnetic disturbances are high-voltage (HV) power lines running close to the railway infrastructure. The purpose was to assess the electromagnetic impact of overhead HV transmission lines on buried signaling cables of the railway traffic control system crossbreeding with them. The levels of voltage induced in the cable under steady state and the earth fault in the HV line at various soil resistivity were estimated. A software tool based on a hybrid numerical method that combines circuit theory and electromagnetic field theory was used for computations. It was found that very high voltages may be induced in the signaling cables during earth faults in the HV lines, which may lead to serious interference or damage to the equipment. The results provide useful knowledge for implementing modern railway traffic control systems and protection measures.

Lightning discharge becomes a serious source of interference and damage for electronic and electrical power systems. Safe and reliable operation of railway traffic control systems requires proper protection against the effects of lightning. However, the current standards on lightning protection, PN-EN/EN/IEC 62305, do not cover railway objects. Moreover, there are no other standards or recommendations dedicated to the railway. The paper is an attempt to apply the procedure of lightning risk management according to PN-EN 62305-2 to select the proper protection measures in railway objects. A case study for the signal box with installed relaying and digital stations of the railway traffic control system is analyzed. The analysis comprises calculations based on the current standard PN-EN 62305-2:2012 but including the issues specific to railway traffic control. The risks of lightning losses have been calculated for two cases: without lightning protection measures and with protection measures proposed to decrease the risks below the tolerable values. The results show that a practically effective solution to reduce the risks is applying surge protective devices with proper characteristics. Another way is replacing unshielded incoming lines with shielded ones of given shield bonding way, and supplementing it with surge protective devices when necessary.

Incorrect adjustment of railway traffic control devices (rtc) to the specificity of the area in terms of lightning density may result in their damage by lightning-caused electromagnetic pulses. An associated risk assessment, as the standard in the analyses of the strength of rtc devices, should be made. However, manufacturers of rtc devices typically do not perform tests with respect to such high overvoltage conditions. Particularly in the case of the EN 62305-2 standard, the manufacturers of new rail traffic control devices usually do not carry out such analyses. In this paper, an analysis of the damage vulnerability of rtc devices caused by lightning discharges for a selected structure, including a signal box equipped with digital rtc devices is presented. The necessity of conducting a lightning damage vulnerability analysis for rtc devices is demonstrated. A part of the railway track where lightning discharges occur was analyzed. The results of the risk analysis obtained with the use of the DEHN Risk Tool software and based on the standard EN 62305-2 (2008, Lightning protection. Part 2. Risk management) are presented. Due to the fact that railway devices are not included in the current standard, three documents were adopted for the analysis: two editions of EN/IEC 62305-2 (from 2008 and 2012) and the recommendations of the ITU-International Telecommunication Union ITU-T K.39 (10/1996). The presented analysis is performed according to the 2008 standard version and to the chosen device.

Currently, scientific research shows an increasing use of artificial intelligence technology to model various types of phenomena. One of such issues is the modeling of the output signals from special electric surge generator. The authors in earlier work presented the model of the output voltage signal from such a generator. This model used the technology of artificial neural networks. This article presents the model of the output current signal from the surge generator. This model also uses an artificial neural network. Both of them, with suboptimal structure, the above models have 1 hidden layer and 4 neurons. The simulation tests of these models showed their high accuracy. Having the model of the output voltage and current from the surge generator available, it is possible to simulate the influence of such signals on various elements of electrical circuits. This can be used, for example, for testing of projected surge protection systems.

Efektywność sztucznych sieci neuronowych w modelowaniu sygnału napięcia generatora udaru kombinowanego