Patent ID: 8138622
Filing Date: 2012-03-20
Classification: G01V

Abstract:
1. A method of powering a motor and an instrument of a submersible pump assembly, comprising: (a) providing a three conductor power cable from a surface location to the motor, which has a Y-point on a lower end of the motor; (b) electrically coupling a capacitor to the Y-point and a side of the capacitor opposite the Y-point to the instrument; (c) producing three phase motor power for the motor and simultaneously producing single phase instrument power on the three conductor power cable, the instrument power being at a higher frequency and lower voltage than the motor power, the instrument power voltage existing at the Y-point and passing through the capacitor to the instrument, the motor power having a motor voltage that is zero at the Y-point; (d) in the event one of the conductors of the power cable shorts to ground, which causes the motor voltage to occur at the Y-point, an impedance of the capacitor increases due to the lower frequency of the motor power than the instrument power, thereby passing to the instrument a reduced level of motor voltage; and (e) bi-directionally transmitting data on the three conductor power cable between the surface location and the instrument by modulating the instrument power, interrupting a frequency of the instrument power, or shifting a frequency of the instrument power.