Vestas Wind Systems A/s

Per Hagen Nielsen

Torsten Lund

Germán Claudio Tarnowski

John Godsk Nielsen

Tusitha Abeyasekera

Bo Lovmand

Keld Rasmussen

Bjørn Priisholm Fuglsang

Ole Helbo

Estimating components of a grid impedance, Z, of a power grid being coupled to a power generating unit at a point of interconnection is disclosed. A voltage, Vmeas, across the point of interconnection; an active current, IP, and/or an active power, P, delivered by the power generating unit to the power grid; and a reactive current, IQ, and/or a reactive power, Q, delivered by the power generating unit are determined. A parameter estimation vector is estimated using a recursive adaptive filter algorithm, and on the basis of Vmeas, IP, P, IQ and/or Q. A model representation of the power grid is created on the basis of the parameter estimation vector, and a system DC gain vector for the power grid is calculated, using the model representation. Finally, Z, and/or a resistance, R, of Z, and/or a reactance, X, of Z, is derived from the system DC gain vector.

Method for grid impedance and dynamics estimation

A method for controlling one or more renewable power generators forming a renewable power plant, and a controller configured to perform the method. In one aspect, plant voltage control is carried out on the basis of a more accurate voltage-reactive power relationship value which is determined dynamically based on grid conditions rather than the conventional approach of the voltage-reactive power relationship being a static value that is based on information provided by a transmission system operator during installation or commissioning of the power plant.

Relating to voltage control in renewable energy power plants

Operating a renewable energy power plant connected to a power network at a point of interconnection. The plant includes: one or more renewable energy generators connected to a collection point of the renewable energy power plant, and a connecting network connecting the collection point to the point of interconnection. One method includes: receiving one or more measurement signals indicative of measured power characteristics of the renewable energy power plant at the point of interconnection; determining a dynamic short circuit ratio (DSCR) at the point of interconnection based on the one or more measurement signals; determining an equivalent dynamic short circuit ratio (EDSCR) at the collection point based on the determined DSCR at the point of interconnection and one or more components of an impedance of the connecting network; and controlling the one or more renewable energy generators by determining and dispatching active power set points based on the determined EDSCR.

Methods and systems for improving grid stability

A method for detecting power oscillation in an electric power grid, wherein the method comprises: integrating a filtered signal on a first interval, the filtered signal being associated with the electric power grid; based on the integration of the filtered signal on the first interval, determining a positive half-period area of the filtered signal and a negative half-period area of the filtered signal, one of the positive half-period area and negative half-period area being immediately subsequent to the other one; and determining that a power oscillation in the electric power grid is detected if the following two conditions are met:

Method for detecting power oscillation in an electric power grid

Aspects of the present invention relate to a method of voltage control for at least one wind turbine generator configured to absorb and supply reactive power on demand, the method comprises: receiving a dispatch signal from a power plant controller indicating a reactive power set point; determining a terminal voltage level of the at least one wind turbine generator; generating a reactive power correction value based on a deviation of the terminal voltage level from a voltage set point; adjusting the reactive power set point by the reactive power correction value; and controlling the at least one wind turbine generator according to the adjusted reactive power set point.

Method and control systems for voltage control in renewable energy power plant

A renewable power plant configured to deliver electrical power to an electrical grid in accordance with a reference is disclosed. The renewable power plant comprises at least one energy generating system of a first type, at least one energy generating system of a second type, and a control system including a central power plant controller (CPPC) which generates setpoints for controlling the energy generating systems in accordance with the reference. The energy generating systems provide feedback signals to the CPPC. The control system is configured to generate a modified feedback signal based on the feedback signal received from the energy generating systems of the second type, and using a model representing operational behavior of the energy generating systems of the second type. The CPPC is configured to apply the modified feedback signal to a feedback control loop for controlling the energy generating systems.

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Tilst, Denmark

Per Hagen Nielsen