Abb Technology Ltd

Abb Schweiz Ag

Hitachi Energy Ltd

Abb Power Grids Switzerland Ag

Nicklas Johansson

Jan Svensson

Stefan G Thorburn

Lennart Harnefors

Tomas Tengner

Panagiotis Bakas

Roberto Alves

Lidong Zhang

Mikko Huotari

Herman HÖRNEQUIST

A method for controlling an output voltage of at least one transformer in a power grid comprises providing the one transformer(s) with a power electronics converter and an output voltage controller, determining a grid frequency, comparing the grid frequency with a reference value, producing an error signal, applying the error signal as feedback to the controller, and generating a control action to cause the controller to change the output voltage of the transformer comprising a power electronics converter. The power electronics converter is an AC-AC converter, and the method comprises connecting the AC-AC converter to either a primary side or a secondary side of the transformer. The AC-AC converter has a first AC side and a second AC side and the method comprises connecting two terminals on the first AC side to a winding of the transformer, and connecting the second AC side to an external circuit line.

Control method, computer program product, control system and use

A method for controlling plant active power output ramp rate of a power plant to a PCC with a power grid includes obtaining information about a current RES active power output of a Renewable Energy Source (RES) in the power plant. The method also includes forecasting future RES active power output, during a predefined future time period. The method also includes, based on the obtained current RES active power output information and on the forecasted RES active power output, determining whether an expected ramp rate of the RES active power output during the predefined time period exceeds a predefined maximum ramp rate limit of a plant active power output. The method also includes, based on the determining, selecting a first control method which is based on the forecasted future RES active power output if it is determined that the expected ramp rate exceeds the predefined maximum ramp rate limit, or selecting a second control method, different from the first control method, if it is determined that the expected ramp rate does not exceed the predefined maximum ramp rate limit. The method also includes using the selected first or second control method to generate an ESS control signal for controlling the ESS active power output Psuch that the plant active power output ramp rate is kept below the predefined maximum ramp rate limit during the predefined time period.

Power plant ramp rate control

Embodiments disclose using a pairing or pairings of terminals in a DC power system including a plurality of terminals to implement power oscillation damping (POD), where the DC power system is connectable to at least one AC power system. The active and/or reactive power of the terminals in the pairing may be controlled or modulated in a similar manner such that no power imbalance in the DC power system is created. For example, POD may be implemented by means of active and/or reactive power modulation by pairing two terminals in the DC power system) such that their active and/or reactive powers are controlled or modulated in the same or substantially the same manner or identically but with the opposite sign.

Method and apparatus for damping oscillations in a power system

It is presented a method executed in a transmission system, the transmission system comprising an AC grid, a DC grid and at least two AC/DC converters connected between the AC grid and DC grid. The method comprises the steps of: obtaining set points for each one of the at least two AC/DC converters, each set point comprising a magnitude and direction of power through the respective AC/DC converter during normal operation generating, based on the set points, a virtual AC grid, the virtual AC grid corresponding to AC behavior of the DC grid, as viewed from each AC side of the at least two AC/DC converters; and controlling the at least two AC/DC converters to mimic a behavior in accordance with the virtual AC grid. A corresponding transmission system is also presented.

Method and associated transmission system

A control apparatus for a controlled series compensator including a plurality of reactance elements each having a rapid switch for connecting and disconnecting the reactance in series with an electric power transmission line. The apparatus also includes a steady state power flow controller. A damping controller is provides on the presence of an oscillation on the transmission line a first reactance insertion on the transmission line having a first duration of time trigged by a time instant that coincides with a peak in the power oscillation.

Growing community of inventors

Västerås, Sweden

Nicklas Johansson