In order to create a full variable shunt reactor having two magnetically controllable high-voltage throttles which is compact and at the same time can also provide capacitive reactive power, auxiliary windings are used which are inductively coupled to the high-voltage throttles. The auxiliary windings are connected to at least one capacitively acting component.

There is provided a transformer system (10) for converting a grid voltage (V.sub.grid) to a regulated voltage (V.sub.regulated) and output the regulated voltage (V.sub.regulated) to a power line (30), the transformer system (10) comprising: a first transformer (40) configured to step down the grid voltage (V.sub.grid) to an unregulated voltage (V.sub.unregulated) and provide the unregulated voltage (V.sub.unregulated) at an output of the first transformer (40); a shunt coupling transformer (50) connected in parallel with the output of the first transformer (40) and further connected to power electronics circuitry (60); and a series coupling transformer (70) connected in series with the output of the first transformer (40) and further connected to the power electronics circuitry (60). The power electronics circuitry (60) adds, via the series coupling transformer, a conditioning voltage (V.sub.conditioning) in series to the unregulated voltage (V.sub.unregulated) to generate the regulated voltage (V.sub.regulated). The first transformer, the series coupling transformer and the shunt coupling transformer are housed in a single transformer tank (80), and the power electronics circuitry is housed in a power electronics enclosure (90) separate from the transformer tank. Each of the transformer tank and the power electronics enclosure comprises one or more openings (95) through which electrical connections (97) between the shunt coupling transformer (50), the series coupling transformer (70) and the power electronics circuitry (60) pass.

A method for exchanging electrical power between an infeed unit, in particular a wind power installation or a wind farm, and an electrical supply grid at a grid connection point is provided. The exchange comprises exchanging active and reactive power, and the exchange of the active power is controlled based on a frequency-dependent and voltage-dependent active power control function. The active power control function specifies an additional active power to be fed in based on a captured grid frequency and a captured grid voltage. The exchange of the reactive power is controlled based on a frequency-dependent and voltage-dependent reactive power control function, where the reactive power control function specifies an additional reactive power to be fed in based on the captured grid frequency and the captured grid voltage. The control functions are set based on at least one grid characteristic and/or at least one grid state of the grid.

A method for exchanging electrical power between an infeed unit, in particular a wind power installation or a wind farm, and an electrical supply grid at a grid connection point is provided. The exchange comprises exchanging active and reactive power, and the exchange of the active power is controlled based on a frequency-dependent and voltage-dependent active power control function. The active power control function specifies an additional active power to be fed in based on a captured grid frequency and a captured grid voltage. The exchange of the reactive power is controlled based on a frequency-dependent and voltage-dependent reactive power control function, where the reactive power control function specifies an additional reactive power to be fed in based on the captured grid frequency and the captured grid voltage. The control functions are set based on at least one grid characteristic and/or at least one grid state of the grid.

Provided is a transformer arrangement wherein active and/or reactive power can be injected in an alternating current link using a current regulator and a voltage regulator portion, wherein at least one winding with which the current regulator is connected in parallel is at least one tertiary winding, and wherein the current regulator includes a number of current regulator sections, each connected to a corresponding voltage regular section of a voltage regulator portion via a corresponding dc link.

A method for controlling a power distribution system having a number of nodes and controllable grid assets associated with at least some of the node includes acquiring observations via measurement signals associated with respective nodes and generating a graph representation of a system state based on the observations and topological information of the power distribution system. The topological information is used to determine edges defining connections between nodes. The observations are used to determine nodal features of respective nodes, which are indicative of a measured electrical quantity and a status of controllable grid assets associated with the respective node. The graph representation is processed using a reinforcement learned control policy to output a control action for effecting a change of status of one or more of the controllable grid assets, to regulate voltage and reactive power flow in the power distribution system based on a volt-var optimization objective.

A method for controlling a power distribution system having a number of discretely controllable devices includes processing a system state, defined by observations acquired via measurement signals from a number of meters, using a reinforcement learned control policy including a deep learning model, to output a control action including integer actions for the controllable devices. The integer actions are determined by using learned parameters of the deep learning model to compute logits for a categorical distribution of predicted actions from the system state, that define switchable states of the controllable devices. The logits are processed to reduce the categorical distribution of predicted actions for each controllable device to an integer action for that controllable device. The control action is communicated to the controllable devices for effecting a change of state of one or more of the controllable devices, to regulate voltage and reactive power flow in the power distribution system.

A system for stabilizing an alternating voltage grid has an inverter, which can be connected to the alternating voltage grid, and is configured to exchange reactive power with the alternating voltage grid. The system further has an inductor arrangement with variable inductor coils, which can be connected to the alternating voltage grid, and a control device, which is configured to control a reactive power in the alternating voltage grid by use of the inverter and by use of the inductor arrangement.

An electrical power distribution network includes: a plurality of electrical power control apparatuses, each of which include one or more signal conversion components receiving electrical power in the form of a first signal and generating a corresponding second signal, a controller that controls operation of the signal conversion components, electrical power generation components acting as sources of electrical power to at least some of the electrical power control apparatuses, and electrical power consumption components acting as sinks of electrical power from at least some of the electrical power control apparatuses. The electrical power control apparatuses operate autonomously but are interconnected so that the electrical power control apparatuses collectively maintain the voltages and frequencies of electrical power signals flowing through the electrical power distribution network at target values to compensate for variations in the sinks and/or sources of electrical power.

An electrical power distribution network includes: a plurality of electrical power control apparatuses, each of which include one or more signal conversion components receiving electrical power in the form of a first signal and generating a corresponding second signal, a controller that controls operation of the signal conversion components, electrical power generation components acting as sources of electrical power to at least some of the electrical power control apparatuses, and electrical power consumption components acting as sinks of electrical power from at least some of the electrical power control apparatuses. The electrical power control apparatuses operate autonomously but are interconnected so that the electrical power control apparatuses collectively maintain the voltages and frequencies of electrical power signals flowing through the electrical power distribution network at target values to compensate for variations in the sinks and/or sources of electrical power.