System and method for an ac powered downhole gauge
AssigneeBaker Hughes Incorporated
InventorsJames E. Layton, Dick L. Knox, Gordon L. Besser
Life of this patent
Estimating the term…
Abstract
Borehole instruments are powered by AC instrument power transmitted on all three phases of a power cable concurrently carrying three phase motor power, the instrument power transmitted at a multiple of the motor power frequency and having a corresponding fraction of the motor power voltage, and received via a capacitive coupling sufficient to withstand high-voltage cable insulation testing. The phase-to-neutral motor power provides approximately the same power level to the borehole instruments if a phase shorts to ground.
Claims18
A borehole instrument power system comprising:
- a three phase power cable extending from a surface location into a borehole, the three phase power cable capable of carrying three phase motor power of voltage and frequency;
- a power source coupled to the three phase power cable, the power source producing alternating current instrument power for transmission on all three conductors of the three phase power cable;
- and
- an instrument capacitively coupled to the three phase power cable to receive the alternating current instrument power over the three phase cable, wherein the alternating current instrument power has a voltage that is less than the three phase motor power voltage and a frequency that is more than the three phase motor power frequency.
A method of powering a borehole instrument comprising:
- providing a three phase power cable from a surface location into a borehole, the three phase power cable capable of carrying three phase motor power of voltage and frequency;
- coupling a power source to the three phase power cable, the power source producing alternating current instrument power for transmission on all three conductors of the three phase power cable;
- and
- capacitively coupling an instrument to the three phase power cable to receive the alternating current instrument power over the three phase cable, wherein the alternating current instrument power has a voltage that is less than the three phase motor power voltage and a frequency that is more than the three phase motor power frequency.
A borehole system comprising:
- a three phase power cable extending from the surface location into the borehole, the three phase power cable capable of carrying three phase motor power of voltage and frequency;
- a power source coupled to the three phase power cable, the power source producing alternating current instrument power for transmission on all three conductors of the three phase power cable;
- an electrical submersible pump coupled to the three phase power cable, the electrical submersible pump including a motor receiving the three phase motor power from the three phase power cable;
- and
- an instrument capacitively coupled to the three phase power cable to receive the alternating current instrument power over the three phase cable, wherein the alternating current instrument power has a voltage that is approximately a fraction 1/N of the three phase motor power voltage and a frequency that is approximately a multiple N of the three phase motor power frequency.
Dependencies are inferred from the claim text.