Title :
A novel high sensitivity differential current transformer for online health monitoring of industrial motor ground-wall insulation
Author :
Neti, Prabhakar ; Younsi, Karim ; Shah, Manoj R.
Author_Institution :
GE-Global Res. Center, Electr. Machines Lab., Niskayuna, NY, USA
Abstract :
The offline capacitance and dissipation factor bridge test is an industry accepted standard test to assess the health condition of ground-wall insulation of industrial motors. However, so far, it was not possible to conduct this test online on large motors due to the great difficulty in online measurement of very small motor insulation leakage currents (few mA) in the presence of large motor line currents (hundreds of amps). The line currents would produce enormous noise to mask the tiny magnetic field produced by the insulation leakage currents. A recently invented novel sensor, High Sensitivity Differential Current Transformer (HSCT), is presented in this paper that enabled online measurement of stator insulation leakage current of large industrial motor for the first time in the world. Thus HSCT also enabled to conduct the industry accepted capacitance and dissipation factor test on large industrial motors for the first time in the industry. Such an online test adds a new dimension to state-of-the-art online condition monitoring and greatly benefits the motor users to continuously assess the insulation condition since no motor outage is required.
Keywords :
capacitance; condition monitoring; current transformers; differential transformers; leakage currents; machine insulation; magnetic fields; stators; HSCT; dissipation factor bridge test; high sensitivity differential current transformer; industrial motor ground-wall insulation; magnetic field; offline capacitance test; online condition monitoring; online health monitoring; online measurement; sensor; small motor insulation leakage current; stator insulation leakage current online measurement; AC motors; Current measurement; Current transformers; Insulation; Leakage currents; Stator windings;
Conference_Titel :
Energy Conversion Congress and Exposition (ECCE), 2013 IEEE
Conference_Location :
Denver, CO
DOI :
10.1109/ECCE.2013.6647022