Radiated emissions measurement of entire railway system including rolling stock for Mumbai Monorail project as per EN50121-2: A case study

Like any other electronic equipment, the train (referred as rolling stock) used for urban passenger transport also consists of lot of electronics embedded into its system. Hence, it is prone for EMI related problems as encountered by any other electronic equipment. As large number of urban population uses these transport services, they need to be operated taking into consideration all safety precautions inclusive of EMI compliance. The EMI related incidence could create a situation wherein lot of people gets stranded or in worst case scenario put lot of lives in danger. In addition to the routine measurements, the measurements relevant to human physiology (passenger wearing a pacemaker in the heart) also needs to be considered. Many EMI incidences have been reported elsewhere in the world. The product specific standard EN 50121-X series is available for which not only the rolling stock needs to be complied for EMI norms but the whole railway system encompassing Traction Sub Stations (TSS), Auxiliary Sub Stations, Beam switch etc. needs to be considered for measurements. Considering the terrain, other noise sources present around and the nature of EUT (always moving), the radiated emission measurement to be conducted for rolling stock is challenging preposition. Due to a very short time of the rolling stock available in front of the receiving antenna for executing a scan for the entire frequency range, various methodology have to be adopted which includes breaking up the band, taking multiple runs, changing the resolution bandwidth or reducing the scan time. In this paper, we are presenting the methodology and results of the radiation emission measurements conducted for Mumbai Monorail, Phase - I project encompassing rolling stock, Traction Sub Station (TSS), Auxiliary Sub Station (ASS) and Beam Switch Assembly. In addition to taking an ambient scan before every measurement, a separate exercise of noise survey for the duration of 6 to 8 hours at all specified locations where radiated emission measurement was planned was also carried out prior to the actual emission measurements. The noise survey was done as per procedure defined in IEEE 273 standard.