Harmonics of a power output of a power plant at a point of common coupling between the power plant and a utility grid, wherein the power plant comprises a plurality of energy production units. The method comprises determining an electrical characteristic at the point of common coupling; determining the electrical characteristic at an output terminal of each of the energy production units and dispatching a control signal to at least one of the energy production units to control the electrical characteristic at an output terminal of the respective energy production units. The control signal is based on the measurement of the electrical characteristic at the point of common coupling and arranged for damping the harmonic of the power output of the power plant at the point of common coupling, wherein the control signal is determined on the basis of a predetermined prioritizing sequence of said electrical characteristic.

Harmonics of a power output of a power plant at a point of common coupling between the power plant and a utility grid, wherein the power plant comprises a plurality of energy production units. The method comprises determining an electrical characteristic at the point of common coupling; determining the electrical characteristic at an output terminal of each of the energy production units and dispatching a control signal to at least one of the energy production units to control the electrical characteristic at an output terminal of the respective energy production units. The control signal is based on the measurement of the electrical characteristic at the point of common coupling and arranged for damping the harmonic of the power output of the power plant at the point of common coupling, wherein the control signal is determined on the basis of a predetermined prioritizing sequence of said electrical characteristic.

An AC transmission system for a power transmission to an offshore plant. The AC transmission system includes an onshore power station which transmits an electric power, an offshore plant which receives the electric power, a submarine cable which connects the onshore power station to the offshore plant, and at least one pipeline with an electrical heating system which is connected to the onshore power station through the submarine cable.

An AC transmission system for a power transmission to an offshore plant. The AC transmission system includes an onshore power station which transmits an electric power, an offshore plant which receives the electric power, a submarine cable which connects the onshore power station to the offshore plant, and at least one pipeline with an electrical heating system which is connected to the onshore power station through the submarine cable.

A distribution system may include at least one Power Management System (PMS) that controls electrical power distributed transmitted by the distribution system. The system may include a first power station located at an onshore platform. The first power station may include an onshore terminal that distributes electric power to the first power station and to at least one onshore load. The first power station may include various onshore reactors that monitor inbound reactive power received from the onshore terminal or that monitor outbound reactive power sent to a remote location. The system may include a second power station located at an offshore platform which is located at the remote location. The second power station may include an offshore terminal that receives electric power from the first power station and that delivers electric power to at least one offshore load.

A distribution system may include at least one Power Management System (PMS) that controls electrical power distributed transmitted by the distribution system. The system may include a first power station located at an onshore platform. The first power station may include an onshore terminal that distributes electric power to the first power station and to at least one onshore load. The first power station may include various onshore reactors that monitor inbound reactive power received from the onshore terminal or that monitor outbound reactive power sent to a remote location. The system may include a second power station located at an offshore platform which is located at the remote location. The second power station may include an offshore terminal that receives electric power from the first power station and that delivers electric power to at least one offshore load.

The invention provides a device for operative connection between a subsea step out cable far end and subsea loads such as pumps, compressors and control systems, distinctive in that the device is a rotating frequency stepper device, more specifically a rotating step up or step down device, and it comprises: a motor and a generator operatively connected so that the motor drives the generator, at least one gas and/or liquid filled vessel into which at least one of the motor and generator are arranged, and the step out length is long, which means long enough to cause problems due to the Ferranti effect at frequency and power levels feasible for subsea pump and compressor motors, and where the device via the step out cable receives input electrical power at a low enough frequency to have stable transmission and the device, operatively connected to the subsea motor, delivers an output electrical frequency, amperage and voltage feasible for operation of the connected motors. System for pressure boosting of hydrocarbon fluid or other fluid subsea, comprising the device.

The invention provides a device for operative connection between a subsea step out cable far end and subsea loads such as pumps, compressors and control systems, distinctive in that the device is a rotating frequency stepper device, more specifically a rotating step up or step down device, and it comprises: a motor and a generator operatively connected so that the motor drives the generator, at least one gas and/or liquid filled vessel into which at least one of the motor and generator are arranged, and the step out length is long, which means long enough to cause problems due to the Ferranti effect at frequency and power levels feasible for subsea pump and compressor motors, and where the device via the step out cable receives input electrical power at a low enough frequency to have stable transmission and the device, operatively connected to the subsea motor, delivers an output electrical frequency, amperage and voltage feasible for operation of the connected motors. System for pressure boosting of hydrocarbon fluid or other fluid subsea, comprising the device.

Methods for transferring electrical power in the sea include: generating AC power; and guiding, at least partially underwater, the AC power through a cable from a first end of the cable to a second end of the cable. A first reactor is connected near the first end of the cable and a second reactor is connected near the second end of the cable. Inductances of the first reactor and the second reactor are selected to at least partially compensate for reactive power generated in the cable.

Methods for transferring electrical power in the sea include: generating AC power; and guiding, at least partially underwater, the AC power through a cable from a first end of the cable to a second end of the cable. A first reactor is connected near the first end of the cable and a second reactor is connected near the second end of the cable. Inductances of the first reactor and the second reactor are selected to at least partially compensate for reactive power generated in the cable.