Wireless Condition Monitoring of Train Traction Systems Using Magnetoelectric Passive Current Sensors

Novel power-supply-free, surface-mount-type magnetoelectric passive current sensors were developed and integrated with a four-channel, 2.4-GHz wireless communication (transmitter and receiver) unit to form a new generation of wireless condition monitor for train traction systems. The wireless condition monitor was deployed in a field study on the East Rail Line in Hong Kong. Four pairs of magnetoelectric passive current sensors and single-channel wireless transmitters were installed, respectively, on and near the electric cables of four electric motor drives located underneath the 2
^nd
, 5
^th
, 8
^th
, and 11
^th
cars of a 12-car mainline train. The four-channel wireless receiver was housed in the driver's cab of the train to provide real-time wireless monitoring of the current signatures of the four electric motor drives due to the operation of the train traction system in steady-state and acceleration conditions. The monitored current signatures were post-processed to obtain the distributions of the ratio of harmonic-to-fundamental current, their total harmonic distortions and power factors as well as the frequency spectra. A practical implication and correlation of the post-processed data with the operating conditions of the train traction system was established for application of the proposed wireless condition monitor as train traction system monitor.