Abstract
Purpose. To conduct an effect research of the electromagnetic field of high-voltage transmission lines (HVTL) (750 kV, 50 Hz) on the track circuits and continuous automatic cab signalling (CACS) with a signal current of 50 Hz in the areas of convergence and intersection with the transmission lines and to propose possible methods to improve noise immunity of CACS. Methodology. The measurements were performed both by means of car-laboratory and directly on rail lines. During the study the electric field strength in the range of industrial frequency directly under the transmission lines and at the distance from it to the railway lines was measured, as well as the time dependence of CACS codes with signal current frequency of 50 Hz directly under the transmission lines and at a distance from it in the absence of the train and its passing. Findings. The root causes analysis of CACS faults and failures was carried out. The effect of the electromagnetic field of highvoltage transmission lines (750 kV, 50 Hz) on the track circuit and CACS with signal current of 50 Hz in the areas of convergence and intersection with the transmission line was investigated. Possible methods to improve noise immunity of CACS were considered. Originality. The effect research of transmission lines (750 kV) on the operation of the automatic cab signalling on spans Prishib-Burchatsk and Privolnoye-Yelizarovo, Pridneprovsk railway in places of oblique railroads crossing and transmission lines (750 kV, 50 Hz) was conducted. Electric field strength in the range of industrial frequency directly under the transmission lines and at a distance from it to the railway line, as well as the time dependences of ALSN codes with signal current frequency of 50 Hz directly under the transmission lines and at a distance from it in the absence of the train and as its passing were measured. It was found that CACS codes in track circuits under transmission lines are strongly distorted, as strength measurements of electric field are shown, it can be explained by the electromagnetic field effect of transmission lines on track circuits. Practical value. Possible methods of CACS safety enhancement by improving the reliability of signaling from a track on the locomotive were considered.
Highlights
In Ukraine there is an increase of train speeds, implementation of accelerated motion, and in the future implementation of highspeed train one, while ensuring the necessary safety level of trains
The work of the ACS is constructed that the devices recognize the new electric signal is not earlier than 5-6 seconds (time delay for releasing the Compliance relay (CR)), which in most cases let protect the system against faults
Maximum EMF of noise induced by transmission lines in the receiver coils can reach 800 mW
Summary
In Ukraine there is an increase of train speeds, implementation of accelerated motion, and in the future implementation of highspeed train one, while ensuring the necessary safety level of trains. Short-term faults and failures of continuous automatic cab signalling (CACS) are connected with a large number of reasons (Fig. 1) [7]. Natural destabilizing factors due to the design features of the track structure and functional characteristics of the system itself, can lead to the interval in signalling and brief glimpses of locomotive traffic lights. The work of the ACS is constructed that the devices recognize the new electric signal is not earlier than 5-6 seconds (time delay for releasing the Compliance relay (CR)), which in most cases let protect the system against faults. Вісник Дніпропетровського національного університету залізничного транспорту, 2014, No 5 (53)
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