Neutral-grounded structure for delta-connected windings and method thereof

作者：Chen Tsai Hsiang; Chen Tai Jou; Liao Rih Neng^*

来源：International Journal of Numerical Modelling: Electronic Networks, Devices and Fields , 2017, 30(6): e2242.

DOI：10.1002/jnm.2242

• delta-connection windings
• grounding winding
• mathematical model
• neutral-grounded structure
• three-phase unbalance

The use of conventional grounding methods in the delta-connected windings can lead to differences of the 3 phase-to-ground voltages, resulting in a number of problems. For example, when a coil of a contactor in a motor control circuit is connected to the improper phase lines of the delta-connected windings, the coil might be broken due to effects of grounded points in the conventional grounding methods. Hence, a specific grounding method, the neutral-grounded structure, was provided for delta-connected secondary windings in which a grounding winding is disposed in at least 1 of the phase windings. The first end of the grounding winding is connected to a grounded point, which functions as a neutral point. The second end of the grounding winding is connected to a tap of 1 of the other 2-phase windings. The voltage-phase displacement between the grounding winding and the corresponding-phase winding is 180 degrees. According to the above-mentioned neutral-grounded structure, all the 3 phase-to-ground voltages are uniform as long as the system remains in balance. This paper presents steady-state models and simulation results by MATLAB/Simulink to verify a neutral-grounded structure for delta-connected secondary windings and method thereof.

• 出版日期2017-12