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Lidong Zhang

Bertil Berggren

Lars-Erik Lennart Juhlin

Ritwik Majumder

Mats Larsson

Lennart Harnefors

Kerstin Linden

Jurgen Häfner

Frans Dijkhuizen

Nicklas Johansson

David Schaeffer

A method for transferring power between medium voltage feeders via a direct current link in a power distribution network includes setting an iteration step value for each of a set of power reference quantities of the link, setting an initial value of each reference quantity, iteratively changing values of each reference quantity, and selecting one changed value of the set by: changing a present value of each reference quantity with the set iteration step value into a new value, measuring a total active power at a substation of the power distribution network for each new value, and selecting the new value that provides the lowest measured total active power at the substation. A next iteration is performed with the selected new value as present value for the one of the set of power reference quantities and with the present value for the other of the set of power reference quantities.

Power transfer between MV feeders in a power distribution network

A method for restoration of a fault isolation in a medium voltage, MV, network having a plurality of feeders and a plurality of normally open, NO, switches possibly in parallel with MV direct current, DC, links is presented. The method is performed in a control device of the MV network. The method includes closing at least two NO switches in parallel with MVDC links of the plurality of NO switches, being connected to a fault isolated feeder of the plurality of feeders of the MV network, and opening the closed at least two NO switches in parallel with MVDC links except one. A control device, a computer program and a computer program product for restoration of a fault isolation in a MV network are also presented.

Restoration of fault insulated feeder

A method of controlling a grid-connected voltage source converter, VSC, using power-synchronization control, wherein the method includes: determining a VSC current vector (i) based on a VSC phase angle (&#x3b8;) which is determined based on an integration of a power control error, determining an active power producing current component (i) of a reference current vector (i) based on an active power reference (P) for the VSC, determining the reference current vector (i) based on the active power producing current component (i), determining a damping component based on a virtual damping resistance (R), the reference current vector (i) and the VSC current vector (i), determining a voltage vector (v) based on a VSC voltage magnitude (V) and the damping component, and controlling the VSC based on the voltage vector (v).

Method and control system for controlling a voltage source converter using power-synchronization 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

A DC grid () comprising a plurality of AC/DC converters () which are interconnected via DC lines () is provided, wherein, in order to limit the effects of a fault in the DC grid, the DC grid is divided into at least two zones () by means of at least one current limiter () in a manner so that a current limiter is connected in each of the DC line(s) () by which two zones are interconnected. A method of limiting the effects of a fault in a DC grid by dividing the DC grid into at least two zones is also provided.

DC grid and a method of limiting the effects of a fault in a DC grid

A current-limitation system for limiting a current through an DC connection in case of a fault occurring in a DC grid of which the DC connection forms a part is provided, as well as a method of operating a current-limitation system for limiting a current through an DC connection in case of a fault occurring in a DC grid of which the DC connection forms a part.

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Västerås, Sweden

Lidong Zhang