A method for controlling a wind farm, which is operated by means of a wind farm control unit and comprises a multiplicity of wind power installations having wind power installation controllers and being connected to one another via a common wind farm grid, which is connected to an electrical power supply grid of a grid operator by means of a wind farm transformer, comprising the following steps: reception of at least one fault bit at the wind farm control unit, in particular at least one fault bit of the grid operator, deactivation of all external setpoint value specifications at the wind farm control unit apart from those of the grid operator after reception of the fault bit, activation of a closed-loop fault case control implemented in the wind farm control unit after successful deactivation of all external setpoint value specifications apart from those of the grid operator.

A method for controlling a power converter of a wind turbine power system connected to an electrical grid. The wind turbine power system has a generator and the power converter has rotor-side converter and a line-side converter. The method includes monitoring an electrical parameter of at least one of the wind turbine power system or the electrical grid. In response to detecting a transient event in the electrical grid, the method includes temporarily disabling the line-side converter of the power converter from the electrical grid. Either during the transient event or after the transient event is over, the method includes implementing a control action for the line-side converter of the power converter. Further, the method includes enabling the line-side converter of the power converter to the electrical grid.

The wide application of power electronic components in power systems with renewable energy sources has changed the fault characteristics of conventional power systems, resulting in the performance degradation of conventional protections. To solve these problems, a novel principle of pilot protection based on structural similarity and square error criteria is provided. The structural similarity criterion utilizes the difference of fault characteristics between renewable sources and synchronous generators to identify internal faults, and the square error criterion is used to solve abnormal calculation of the conventional similarity based protection. Compared with conventional differential protections, the disclosed protection shows excellent performance in speed and reliability during various faults.

Provided is an uninterruptable power supply device. An uninterruptable power supply device 100, which is provided between a commercial power system 10 and an essential load 30 and which provides AC power to the essential load 30, wherein the uninterruptable power supply device 100 is provided with: a power supply unit 2, which has a power converter 22 and a storage battery 21 and which is connected to a power line L1; an open switch 3 for opening the power supply line L1; a system abnormality detection unit 5 for detecting a system abnormality, which is at least one of voltage rise, phase fluctuation, voltage imbalance, harmonic abnormality, and flicker, in addition to at least one of frequency fluctuation and voltage drop including instantaneous voltage drop; and a control unit 6 which, opens the open switch 3 and supplies AC power to the essential load 30.

A method for operating a renewable energy power plant comprising a plurality of renewable energy generators, a plurality of power dissipation systems and a battery storage system is provided. The method comprises steps of: monitoring the statuses of the power dissipation systems; performing a ramped active power recovery operation following a voltage deviation, and controlling the battery storage system during the ramped active power recovery operation to absorb power generated by the renewable energy generators in dependence on the monitored statuses of the power dissipation systems.

Systems and apparatuses include a non-transitory computer readable media having computer-executable instructions embodied therein that, when executed by a circuit of a power system, causes the power system to perform functions to activate and deactivate routes. The functions include determining a plurality of source objects, each including source functions and being assigned a position on a one-line topology; determining one or more switch objects, each including switch functions and being assigned a position on the one-line topology; determining one or more bus objects, each including bus functions and being assigned a position on the one-line topology; determining one or more load objects, each including load functions and being assigned a position on the one-line topology; and allocating each object to one of a plurality of controllers, each of the controllers structured to cooperatively perform the source functions, the switch functions, the bus functions, and the load functions to provide operation of the system.

A power supply system is operable to harvest power at low and high line currents. A current transformer is arranged to couple to a power transmission line. A current sensor which may be a Rogowski coil is arranged to couple to the power transmission line. Branches of power supply circuitry are connected to a plurality of secondary windings of the current transformer. A control circuit selects one of the branches of power supply circuitry, depending on sensed magnitude of line current, to provide electrical power to an output capacitor. Sufficient stored energy is also provided for performing a backup of operating parameters when the line current reduces to zero.

Unique systems, methods, techniques and apparatuses of fault mitigation are disclosed. One exemplary embodiment is a fault mitigation system for a medium voltage alternating current (MVAC) distribution network including a direct current (DC) link and a control system. The DC link is coupled to a first feeder line and a second feeder line. The control system is structured to determine a first feeder line is deenergized, operate the DC link so as to receive MVAC from a second feeder line and output low voltage alternating current (LVAC) to the first feeder line, operate a plurality of isolation devices, measure the LVAC in response to operating the plurality of isolation devices, determine a fault is isolated from a healthy portion of the first feeder line using the received LVAC measurements, and reenergize the healthy portion of the first feeder line.

Aspects of the subject disclosure may include, a system that facilitates detecting a transient electrical signal on a transmission medium that facilitates propagation of electromagnetic waves induced by the waveguide system and generating signal data associated with the transient electrical signal. Other embodiments are disclosed.

The present invention provides a high voltage direct current (HVDC) transmission system (300, 600) comprising: a first station (102) comprising series-connected first and second HVDC converters (110, 130); a second station (104) comprising series-connected third and fourth HVDC converters (150, 170), wherein a neutral node (164) coupling the third HVDC converter (150) to the fourth HVDC converter (170) is coupled to earth; a first transmission line (200) connecting a positive node (114) of the first HVDC converter (110) to a corresponding positive node (154) of the third HVDC converter (150), wherein a first pole (240) of the system (300, 600) comprises the first HVDC converter (110), the third HVDC converter (150) and the first transmission line (200); a second transmission line (210) connecting a negative node (138) of the second HVDC converter (130) to a corresponding negative node (178) of the fourth HVDC converter (170), wherein a second pole (250) of the system (300, 600) comprises the second HVDC converter (130), the fourth HVDC converter (170) and the second transmission line (210); characterised in that: a neutral node (124) connecting the first HVDC converter (110) to the second HVDC converter (130) is coupled to a parallel combination of a resistance (310) and a neutral bus ground switch (312) for coupling the neutral node (124) to earth.