Systems and methods for ground fault immune data measurement systems for electronic submersible pumps

A method of transmitting data from a downhole region of a well, comprising:

• receiving sensor data from a plurality of sensors located in a downhole unit of a data measurement system, the downhole unit located in the downhole region of the well;
• encoding the sensor data in at least three frequency modulated carrier signals via a modulator of the downhole unit;
• multiplexing the at least three carrier signals to produce multiplexed carrier signals via a multiplexer of the downhole unit;
• shunting the multiplexed carrier signals to a 3-phase cable via a capacitive coupling across each motor winding of a 3-phase motor of an electric submersible pump (ESP);
• and
• transmitting the multiplexed carrier signals to a surface unit via each line of the 3-phase power cable.

A data measurement system coupled to an electric submersible pump (ESP) located in a downhole region of a well, the data measurement system comprising:

• a plurality of sensors configured to produce sensor data;
• a processor configured to encode the sensor data in a first frequency modulated carrier signal at a first frequency, a second frequency modulated carrier signal at a second frequency, and a third frequency modulated carrier signal in a third frequency,
• wherein the processor is further configured to decode control data received in a fourth frequency modulated carrier signal at a fourth frequency, wherein the first frequency, second frequency, third frequency, and fourth frequency are different frequencies;
• and
• a capacitive coupling to three motor windings of a 3-phase motor of the ESP, wherein the frequency modulated carrier signals are transmitted across the capacitive coupling to a 3-phase power cable.