A cable that includes a conductor defining a hollow interior, a casing surrounding the conductor, an electrical insulator positioned between the conductor and the casing, and a fluid positioned within the hollow interior of the conductor.

In accordance with at least one aspect of this disclosure, there is provided a method of accelerating a gas turbine engine. The method includes adding torque to a core of the gas turbine engine to accelerate rotation of the core by controlling fuel flow to a plurality of fuel injectors of the gas turbine engine. The method also includes adding torque to the core by powering an electric machine that is operatively connected to the core. In embodiments, controlling fuel flow to the plurality of fuel injectors is based on feedback from the electric machine.

In accordance with at least one aspect of this disclosure, there is provided a drive shaft system. In embodiments, the drive shaft system includes a generator shaft extending along a longitudinal axis with a longitudinal bore defined through the generator shaft. A thru shaft extends through the longitudinal bore of the generator shaft. In embodiments, the thru shaft includes, a front coupler mount at a first end operative to receive torque input, and a rear coupler mount at a second end opposite the first end.

A compressor wheel is provided for the output shaft. Air bleed ports are formed in a shroud case that surrounds the compressor wheel. A plurality of air bleed passages are formed in the engine housing that surrounds the shroud case. An annular chamber is formed between the air bleed ports and the air bleed passages, for storing compressed air that is extracted from the air bleed ports.

In a rotary electric machine housing, a first bearing and a second bearing are provided for supporting a rotating shaft. A lubricating oil is supplied to the first bearing and the second bearing. At least one of the first bearing or the second bearing is sandwiched between the compressed air supplied from one side of the rotating shaft in an axial direction thereof and the compressed air supplied from another side of the rotating shaft in the axial direction.

In some examples, a gas turbine engine including a high-pressure (HP) spool assembly including a HP shaft, a HP compressor and HP turbine; a lower pressure (LP) spool assembly including a LP shaft and LP turbine; a motor-generator coupled to the LP shaft; and a controller. The controller is configured to control the motor-generator to operate in a motor mode to apply torque the LP shaft during a starting of the HP spool assembly, and control the motor-generator to operate in a generator mode for a least a period of time following the starting of the HP spool assembly.

A turbo device provides a flow-path arrangement in a generator device. Part of a working fluid are used to lubricate at least one of a first bearing part, a second bearing part and a bearing assembly, or the working fluid of an auxiliary flow channel is led to a generator housing for cooling the generator device. In addition, a circulatory system is also provided to include bearing loops and auxiliary loops for leading the working fluid to lubricate at least one of the first bearing part, the second bearing part and the bearing assemble part, and to cool the generator device.

A system can include a gas turbine and a processing system. The gas turbine can include a compressor coupled to a turbine through a shaft. The processing system can be configured to: automatically transition an operating condition of the system through a plurality of operating states; determine an efficiency of the system at each of a plurality of the operating states; for each of the plurality of operating states: select a future operating state of the system based on the determined efficiency of the current operating state.

Systems and methods for generating and a controller for controlling generation of geothermal power in an organic Rankine cycle (ORC) operation in the vicinity of a wellhead during hydrocarbon production to thereby supply electrical power to one or more of in-field operational equipment, a grid power structure, and an energy storage device. In an embodiment, during hydrocarbon production, a temperature of a flow of wellhead fluid from the wellhead or working fluid may be determined. If the temperature is above a vaporous phase change threshold of the working fluid, heat exchanger valves may be opened to divert flow of wellhead fluid to heat exchangers to facilitate heat transfer from the flow of wellhead fluid to working fluid through the heat exchangers, thereby to cause the working fluid to change from a liquid to vapor, the vapor to cause a generator to generate electrical power via rotation of an expander.

A hydraulic fracturing system for fracturing a subterranean formation includes a primary switchgear arranged on a support structure. The system also includes a secondary switchgear, arranged on the support structure, the secondary switchgear positioned separately from the primary switchgear and within an enclosure, the secondary switchgear receiving an electrical input from the primary switchgear and including an plurality of feed connections for supplying electrical power to a plurality of fracturing equipment.