A system and methodology are provided for improving telemetry over a three-phase electrical power cable of the type used to provide power to electric submersible pumping systems or other powered devices. Data communication is provided between one end of a three-phase electrical power cable coupled with an electric power source and the other end of the three-phase electrical power cable coupled to a powered device, such as an electrical motor. The system and methodology enable a reduction in the level of common mode noise generated by, for example, a variable speed drive and/or enable minimizing or eliminating the common mode noise before mixing with data communication signals.

A well tool for use in a wellbore can include a motor for performing a well operation. The well tool can include a switch that is couplable between the motor and a wireline. The switch can be toggleable between (i) a first operational state for providing the power to the motor by coupling the motor to an external power source and (ii) a second operational state for decoupling the motor from the external power source. The well tool can include a motor controller coupled to the switch for toggling the switch between the first operational state and the second operational state in an arrangement configured to impart, on the wireline, multiple current pulses including data encoded in the current pulses according to an encoding scheme.

An inspection apparatus for use in wellbores in the oil and gas industries relates in general to the field of transmission of data between downhole module in a wellbore and a controlling module at the surface. The invention provides a method and apparatus for determining analog filter parameters for an analog front end comprising a plurality of filter stages receiving signals from a telemetry module, by repeating the steps of; receiving a signal of a known frequency and processing said signal by determining the magnitude of the frequency of the received signal until a plurality of signals have been received and processed; calculating an optimum set of filter parameters in dependence upon the measured frequency magnitudes and a predefined set of filter stage frequency responses.

A well tool for use in a wellbore can include a motor for performing a well operation. The well tool can include a switch that is couplable between the motor and a wireline. The switch can be toggleable between (i) a first operational state for providing the power to the motor by coupling the motor to an external power source and (ii) a second operational state for decoupling the motor from the external power source. The well tool can include a motor controller coupled to the switch for toggling the switch between the first operational state and the second operational state in an arrangement configured to impart, on the wireline, multiple current pulses including data encoded in the current pulses according to an encoding scheme.

A communication system for transmitting electrical power and data between a first end of a transmission line and a second end of the transmission line comprises, at the first end: a DC supply means for supplying direct current to the transmission line; first switching means for switching the DC supply means; and a first modulator for operating the first switching means. At the second end, the system comprises an energy storage means for storing and supplying DC power; second switching means for switching power from the energy storage means; and a second modulator for operating the second switching means.

An electric submersible pump system can include a multiphase electric motor operatively coupled to a fluid pump where the multiphase motor includes a wye point; telemetry circuitry operatively coupled to the wye point where the telemetry circuitry generates AC telemetry signals; a multiphase power cable operatively coupled to the multiphase electric motor; and a tune filter operatively coupled to the multiphase power cable where the tune filter passes and amplifies AC telemetry signals generated by the telemetry circuitry, the AC telemetry signals being transmitted to the multiphase power cable via the wye point. Various other apparatuses, systems, methods, etc., are also disclosed.

A system and method for transmitting data over a three phase power system between a surface and a sub-surface location. A first power supply providing a first AC power signal and a second power supply providing a second AC power signal are at the surface. A first powered module and a second powered module which provides a data communications signal are at the sub-surface. A cable connection is provided between the surface and the sub-surface to transmit the power and data communication signals. The data communications signal provides an indication of power applied to the second powered module and a power signal is varied in response to the applied power. The invention finds specific application monitoring down hole equipment such as an electrical submersible pump in a wellbore.

A ground fault immune power and data delivery system for downhole sensors is connected to a downhole motor via a three-phase power cable. An AC power supply and sensor data module are connected to only two of the three phases to provide power and data signals to the sensors. During normal operation, power and data signals are transmitted over only one of the two connected phases. If a ground fault is detected on the third unconnected phase, power and data signals continue to transmit over the connected phase. If a ground fault is detected on one of the two connected phases, an isolation module isolates the grounded phase and switches to the ungrounded connected phase to continue transmitting power and data signals. If two of the phases are grounded, the motor shuts off; however, power and data signals may continue to transmit over an ungrounded connected phase.

A method for transmitting data in a frequency selective communication channel in provided. The method comprises: parsing data to be transmitted into a plurality of data fields; assigning the data from each data field into a corresponding one of a plurality of sub-channels; modulating the data from each of the plurality of sub-channels into a corresponding one of a plurality of sub-bands, the plurality of sub-bands having spaced apart center frequencies; and concurrently transmitting the data from the plurality of sub-bands onto the channel.

A three phase power system provided with a data communications system and associated method of data transmission for transmitting data over a three phase power system between a surface and a sub-surface location for an arrangement such as an oil field electrical submersible pump, the data communications system comprising a cabled connection from a surface system to a sub-surface system; a power module coupled to the cabled connection via a tuned circuit tuned to a first frequency, a data signal module coupled to the cabled connection via a tuned circuit tuned to a second frequency, independently of the coupled power module so as to minimize interference between the power signal module and data signal module during operation.