The high-speed EMU power supply system of electric traction refers to a complete system, which receives electric power from a power system or primary power supply system, and provides the required current to the electric locomotive load through transformer, phase change or commutation (converting the industrial frequency AC to a low frequency AC or DC voltage), and complete the complete system of traction power transmission, power distribution and other functions etc. The performance of the power supply system of electric traction directly affects the traction power of the train and the performance of the traction drive control system.
The power supply system of electric traction is mainly composed of traction substations, traction networks, partitions, and opening and closing sections.
Traction substation equipment includes traction transformers, circuit breakers, electric and manual disconnectors, surge arresters, voltage and current transducers, secondary protection systems, and AC/DC power systems, etc.
Recently, we have released AIT series transducers for high-precision current measurement in the field of railway traction, and new standards for measuring DC, AC and pulse currents.
Our AIT sensor series consists of three models:AIT1000-SG,2000-SG and 4000-SG，. The corresponding rated current measurements are 1000, 2000 and 4000A. The precision of our AIT series designed for the railway-traction industrial unit can reach 0.5R, while the prEN50463 standard requires the on-board energy monitoring accuracy to be 1R. The AIT series are featured as a linearity error of less than 0.05% and an offset current of less than +/-20A.
The railway-locomotive industry asks for unprecedented accuracy. One of the reasons is to maintain the best control of the traction motor, but the most important is to measure energy and record the use of energy for financial purposes, for example, to record the electricity costs of trains across regions. This industry complies with the tentative standard prEN50463.
Accurate energy metering relies on accurate current and voltage measurements. We are able to provide a full range of current transducers which meet the prEN50463 standard.
Our experts believe that Hall-effect measurement techniques cannot provide the required accuracy. Therefore, we use multi-point zero-flux technology, which has high precision, linearity, low temperature drift, and eliminate insertion loss. The HIT series transducers are insensitive to the position of the primary conductor inside the perforation, providing an insulation test voltage of up to 14kVRMS/50Hz/1min, a very strong instantaneous overcurrent capability (100kA for 100msec) and resistance to external disturbances (e.g. magnetic fields in a typical railway environment).
Current consumption ranges from less than 80mA to +/-340mA (full scale) with a +/-24V DC supply. The bandwidth of the HIT4000-S is 82 kHz (3 dB). The maximum diameter of the conductor perforated to allow insertion is 102 mm (HIT4000-S), 63 mm (HIT2000-S). The test coil allows the HIT transducer to easily determine the state of the transducer with no current on the primary side.