A dual-mode combined control method for a multi-inverter system based on a double split transformer is provided. For an extremely-weak grid, the method provides the dual-mode combined control method for a multi-inverter system based on a double split transformer. According to the method, the equivalent grid impedance at a point of common coupling (PCC) of one grid-connected inverter (GCI) in the multi-inverter system based on the double split transformer is obtained with a grid impedance identification algorithm, and the system sequentially operates in a full current source mode, a hybrid mode, and a full voltage source mode according to a gradually increasing equivalent grid impedance, thereby effectively improving the stability of the multi-inverter system based on the double split transformer during variation of the strength of the grid. The method ensures that the system can still operate stably in the extremely-weak grid.

A method for controlling charging of at least one electrical storage device is disclosed. Information regarding a power grid and the at least one electrical storage device is used by an aggregator to derive a weighted distribution of virtual inertia response and fast frequency response to be provided to the power grid by the electrical storage devices. A total power available for charging the at least one electrical storage device is derived in accordance with the weighted distribution by a charging controller. An active power setpoint is derived for each of the at least one electrical storage device on the basis of at least (i) the total available power and (ii) the information regarding the at least one electrical storage device. Finally, a charging state of each of the at least one electrical storage device is controlled based on the derived active power setpoint.

A power management server includes a receiver for receiving, from an upper management server, an adjustment request for requesting a fluctuation adjustment of a frequency of a power grid for each fluctuation cycle of an adjustment target, a transmitter for transmitting, to an adjustment power supply, an adjustment instruction for instructing the fluctuation adjustment of the frequency of the power grid according to the fluctuation cycle of the adjustment target requested by the adjustment request, a management unit for managing a correspondence relationship between the fluctuation cycle of the adjustment target instructed by the adjustment instruction and the adjustment power supply, and a controller for determining an adjustment power supply to which the adjustment instruction is to be transmitted based on the correspondence relationship.

A simulation method of distributed collaborative control for a microgrid under the attack of false data injection based on cyber-physical fusion is provided, which includes: establishing a distributed collaborative control simulation model for the microgrid frequency based on an RT_LAB real-time simulation tool OPAL-RT; designing a distributed collaborative control algorithm of a microgrid under the attack of false data injection based on DSP; simulating real-time communication among distributed generations based on an OPNET; simulating constant injection of false data, to realize that the frequency of each distributed generation in the microgrid is finally strictly tracked to the reference frequency. According to the method provided by the present application, no extra state observer is needed to observe the angular frequency states of local and neighboring nodes, so that the adverse effects caused by the attack of false data with a constant injection can be completely eliminated.

A method for attenuating low-frequency oscillations in an electrical power supply grid by means of a feed device which feeds into the electrical power supply grid, in particular a wind power installation, wherein the electrical power supply grid has a grid voltage and a grid frequency, comprising the following steps: picking up a grid signal having the low-frequency oscillations, splitting a total frequency range of the grid signal in which oscillations to be attenuated are to be expected into a plurality of partial frequency ranges, each having a lower and an upper range frequency, performing in each case one frequency analysis of the grid signal for each partial frequency range in order to identify in each case one or more oscillations having an oscillation frequency in the partial frequency range, if present, identifying a low-frequency oscillation to be attenuated as target oscillation depending on the frequency analyses of all of the partial frequency ranges, detecting the target oscillation at least according to frequency and amplitude and optionally according to phase, determining a setpoint attenuation signal depending on the target oscillation detected according to frequency and amplitude and possibly phase for attenuating the detected target oscillation, generating a setpoint feed signal depending on the setpoint attenuation signal and a basic setpoint signal, and generating and feeding in a feed signal depending on the setpoint feed signal (QE).

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.

A control system and method for an inverter-based resource device provided in a synchronous power grid. The control system includes at least one inverter based resource device connected to an electrical power system, and a controller module. The inverter based resource device includes a reference power Pref, a combination module and a transfer function. The inverter based resource device injects modulated power into the power system. The power system (which is represented by a transfer function in the control system) receives an undesirable forced oscillation, which is connected to a measuring device. A controller module processes the measured output and provides a control signal to the inverter based resource device. The controller is arranged to suppress a forced oscillation detected in the power system.

The present invention discloses a unit commitment method considering security region of wind turbine generators with frequency response control, and the main steps are: 1) determining security region of wind turbine generators when provides frequency response; 2) based on the security region of the wind turbine generators when provides frequency response, establishing a unit commitment model considering security region of wind turbine generators; and 3) calculating the unit commitment model considering the security region of the wind turbine generators by using mixed-integer linear programming method, and obtaining the operation result of the unit commitment considering the security region of the wind turbine generators with frequency response control. The present invention can be widely used in the setting of frequency response parameters of wind turbine generators dispatched in the prior art and the start-stop and output plans of synchronous generator.

A storage battery system includes a first storage battery unit. First storage battery unit includes a first converter that converts alternating current and direct current, a first storage battery, and a first controller that controls first converter, and first storage battery unit is interconnected to a system for supplying power. The first controller detects a frequency of the system, and controls first converter such that first storage battery outputs constant active power to the system on the basis of the frequency of the system falling below a first threshold value.

A method for providing grid-forming control of an inverter-based resource includes receiving, via a controller, one or more reference commands from an external controller. The method also includes determining, via the controller, one or more control commands for the inverter-based resource based on the one or more reference commands. Further, the method includes determining, via the controller, at least one feedforward signal as a function of the one or more control commands, one or more control signals, and one or more estimated electrical conditions of the inverter-based resource. The method also includes using the feedforward signal(s) to position at least one control angle of the inverter-based resource to an anticipated value needed to achieve the one or more reference commands, thereby enabling rapid response to the one or more reference commands received from the external controller.