A power control device for an electrolyzer that is configured to encode power curtailment information as a DC bus voltage level using a DC droop characteristic in first stage and decode the DC bus voltage to power information in a second stage.

For a simple and reliable data communication in an arrangement composed of a plurality of inverters (3.sub.1, 3.sub.2, . . . 3.sub.n) connected in series and a network monitoring unit (5) it is provided that the network monitoring unit (5) superimposes a synchronization pulse (10) to the network voltage (V.sub.N) applied to the electrical load (4), which synchronization pulse can be detected by the inverters (3.sub.1, 3.sub.2, . . . 3.sub.n) for temporal synchronization.

The invention concerns a switching system (6) for activating and deactivating of an electrical appliance (100) comprising a remote switch control device (9) that comprises a first terminal (90) electrically connected to a first power line (8), a second terminal (91) electrically connected to a second power line (7), and a third terminal (92) connectable to an electrical 5 terminal of the electrical appliance. The remote switch control device (9) is configured to modify the electrical connection between the first and the third terminal (90, 92) in response to a detection of an attenuation of an electrical parameter between the first and second terminals (90,91) caused by a electromechanical switch (1) configured to be manually actionable by 10 a user. The invention further concerns the remote switch control device (9) and a method for installing a switching system using the remote switch control device (9) and the electromechanical switch.

The present disclosure relates to methods (100, 200) for operating in wind farm grids (108) of wind farms (105) which are electrically disconnected from a utility grid (102), for example wherein communication with a wind farm controller (109) has been lost. The present disclosure further relates to wind farms (105), wind farm grids (108) and wind turbines (10). A method (100) comprises operating one or more first wind turbines (111) to generate electrical power with predetermined electrical characteristics when the wind farm (105) is disconnected from a utility grid (102), and delivering the electrical power with the predetermined electrical characteristics to the wind farm grid (108); and one or more second wind turbines (112) detecting (120) the electrical power delivered to the wind farm grid (108) and determining that the wind farm (105) is disconnected from the utility grid (102) by identifying the predetermined electrical characteristics.

An energy storage system including a plurality of loads each converting direct current (DC) power stored in a battery thereof into alternating current (AC) power and outputting the AC power, a plurality of slave power controllers detecting zero crossing points of AC voltage signals output from one of the plurality of loads and controlling the plurality of loads in accordance with a control signal received from a master power controller, and the master power controller controlling the plurality of slave power controllers so as to control the plurality of loads in accordance with the control signal received from the master power controller after a preset time has lapsed since the detected zero crossing point.

A detection system of distributed generation islanding based on power frequency carrier, the detection system comprising: a power frequency carrier signal generating device; a power frequency carrier signal detection device; a signal coupling transformer; a substation bus; a distribution power generator (DG); and a safety isolation breaker, wherein the power frequency carrier signal generating device comprises a voltage and current monitor circuit, the power frequency carrier signal generating device is connected with the signal coupling transformer through four three phase four line power cables, and the signal coupling transformer is connected with substation bus through 3 power cables.

A power generation system includes a power source that is configured to communicate with at least one of a downstream load or a downstream device by changing a voltage on a power bus between the power source and the at least one of the downstream load or the downstream device, while power source provides power on the power bus to the at least one of the downstream load or the downstream device.

In an identification information receiving device connected to an identification information transmitting device by a power line, a measurement value obtainment unit obtains a measurement value of an electric current or a voltage in the power line. An identification information reading unit reads, as binary data, identification information defined by a plurality of bits and superimposed on the electric current or the voltage in the power line by the identification information transmitting device, by determining whether the measurement value corresponding to each bit of the identification information is greater or less than a determination threshold value (other than 0). A threshold value setting unit compares the latest determination threshold value and the measurement value corresponding to each bit of the identification information superimposed on the electric current or the voltage in the power line, calculates two representative values that are a representative value of the measurement value greater than or equal to the determination threshold value and a representative value of the measurement value less than the determination threshold value, and sets the determination threshold value to an intermediate value between the two representative values as an updated determination threshold value.

Systems and methods to send or receive redundant Generic Object Oriented Substation Event (GOOSE) messages are described. An intelligent electronic device may obtain power system data from a power system. The TED may publish the power system data in a first GOOSE message and publish the same power system data in a second GOOSE message. The second GOOSE message may have different header information than the first GOOSE message to allow the subscriber to determine that the redundant GOOSE messages are both received. If the first and second GOOSE message are duplicates with identical header information but unique trailer information methods allow the subscriber to determine that the duplicate GOOSE messages are both received.