Abb Research Ltd.

Telefonaktiebolaget Lm Ericsson (publ)

Abb Technology Ag

Abb Ab

Abb Schweiz Ag

Abb Technology Ltd

Tomas Lars Jonsson

Peter Ökvist

Staffan Norrga

Sasitharan Subramanian

Per Anders Holmberg

Frans Dijkhuizen

Peter Lundberg

Dan Olov Halvarsson

Bertil Berggren

Jean-Philippe Hasler

Falah Hosini

Mauro Monge

Jan Svensson

Bo Bijlenga

Lennart Harnefors

Udo Fromm

Christian Sasse

Mikael Dahlgren

Anshuman Shukla

Filippo Chimento

Gunnar Asplund

Mehdi Amirijoo

Jing Fu

Jiuping Pan

Reynaldo Nuqui

Ritwik Majumder

Tamas Borsos

Jyoti Sastry

Lennart Angquist

David Lindegren

Jiaqi Liang

Jürgen Häfner

Alireza Nami

Björn Jacobson

Anders Bo Eriksson

Gunnar Russberg

Mats Hyttinen

Kjell Svensson

Fredrik Tinglow

Praveen Kumar Barupati

Subhasish Mukherjee

Soubhik Auddy

Tobias Carl Roos

Tomas Larsson

Konstantinos Papastergiou

Pan Min

Gunnar Ingeström

Kailash Srivastava

Dimitris Giannoccaro

Johan Lindberg

Kalpesh Hirjibhai Bhalodi

Svante Soderholm

Thomas Setz

Giovanni Velotto

Michael Rosendahl

Lennart Michael Rosendahl

Carl Heyman

Lars-Erik Lundstrom

Niklas Johansson

Arne Gustafsson

Karin Thorburn

Aneeshkumar As

Kalpesh Bhalodi

Jenny Josefsson

Mukherjee Subhasish

Bopparaju Gopichand

Kerstin Lindén

Fredrik Tinglöw

Nicklas Johansson

Esie Ramezani

Peter Hessling

Dan Olov Halvorsson

Fotis Stergiopoulos

A converter cell includes a first terminal; a second terminal; a plurality of switching elements provided with respective gate units; an energy storage element; an clamp inductor provided to restrict a rate of change of current from the energy storage element to the switching elements; and a first energy converter provided in parallel to the clamp inductor. The first energy converter is provided to power the gate units by utilising energy from the clamp inductor when the converter cell changes state to be in a short circuit state.

Converter cell comprising an energy converter in parallel to a clamp inductor

The invention concerns a switchyard for interconnecting direct current power networks and a direct current power transmission system comprising such a switchyard. The switchyard comprises a number of interconnected entities comprising at least two main circuit breakers and a number of transfer switches, where each network has two connections to the switchyard, at least one via a transfer switch, each main circuit breaker has four connections in the switchyard, two at each end of the main circuit breaker and at least one via a transfer switch, and each network is joined with every other network via a corresponding path through at least one main circuit breaker as well as via a corresponding path bypassing all main circuit breakers.

Scalable switchyard for interconnecting direct current power networks

A multilevel converter includes a first and a second converter block series-connected between two DC terminals and a chopper circuit between the blocks. Each block includes a number of valve arm strings, each including an upper and a lower valve arm and a number of converter cells. A midpoint between the upper and lower arm of a string of the first block is connected to a corresponding primary AC terminal and a midpoint between the upper and lower arm of a corresponding string of the second block is connected to a corresponding secondary AC terminal. The chopper circuit comprises a power dissipating element in parallel with a circuit breaker.

Multilevel converter with a chopper circuit

A voltage source converter includes a number of valves, the valves including switching elements with anti-parallel diodes provided in a bridge for switching between two states. The bridge is provided in at least one phase leg that stretches between two direct current poles and has at least one midpoint, which is connected to an alternating current terminal. The switching element of at least one valve is a thyristor. The converter further includes a commutation cell associated with the valve, where the commutation cell is controllable to reverse-bias the valve if it is to stop conducting current.

Thyristor based voltage source converter

A method for detecting a malfunction in a cell of a telecommunication network is disclosed. The cell is adapted to serve a plurality of user devices identified by user identities and to handle signaling and/or data traffic between the network and the user devices. A lack of traffic is detected in the cell. Further, at least one user identity which identifies a user device is selected. The selected user device is served by the cell. Then a paging message is sent to the user device which is identified by the at least one selected user identity. Finally the malfunction of the cell is validated in case no response message is sent by the user device to said paging message.

Method, device and program for validation of sleeping cells in a communications network

The present invention relates to an AC/DC converter station for interconnection of a DC transmission line and an AC network, the AC/DC converter station including an AC/DC converter and a control system configured to control the AC/DC converter. The AC/DC converter station comprises a capacitor connected in series between the AC/DC converter and the AC network, and a voltage measurement device arranged to measure the voltage across the capacitor. The AC/DC converter further comprises a control system connected to the voltage measurement device and arranged to receive, from the voltage measurement device, a signal indicative of a measured voltage. The control system is arranged to perform the control of the AC/DC converter in dependence of the signal received from the voltage measurement device. The invention further relates to a method of operating an AC/DC converter station.

AC/DC converter station operated in dependence of voltage of capacitor connected in series between AC/DC converter and AC network interface and a method of operating the same

An arrangement for tapping power from a DC power line to an AC power line includes power transfer modules between two DC potentials, each including a first branch with a string of converter cells in parallel with a second branch including a capacitor and being connected to an AC phase. There is at least one control unit that controls the arrangement considering one or more of a) distributing appropriate AC and DC voltages in converter output voltages of all series connected modules, b) maintaining/setting cell capacitor voltages in specific range and allowing boost mode operation, c) performing possible balancing of the introduced capacitor and d) employing an alternate approach of using passive filters to mitigate low order harmonics.

Arrangement, method and computer program product concerned with tapping of power from a DC power line to an AC power line

An arrangement for controlling the electric power transmission in a high voltage direct current, HVDC, power transmission system includes at least one HVDC transmission or distribution line for carrying direct current, DC, and the arrangement includes an apparatus connectable to the HVDC transmission or distribution line, the apparatus being arranged to control the direct current of the HVDC transmission or distribution line by introducing a DC voltage in series with the HVDC transmission or distribution line. The arrangement includes a protection device for protecting the apparatus against over-current or overvoltage occurrences. The protection device includes a bypass device connectable to the HVDC transmission or distribution line and connected in parallel with the apparatus. The bypass device is arranged to be in a non-conducting mode and arranged to be set to a conducting mode. When being in the conducting mode, the bypass device is arranged to conduct direct current of the HVDC transmission or distribution line to electrically bypass the apparatus. A HVDC power transmission system includes at least one arrangement of the above-mentioned sort. A method for protecting an apparatus against over-current or overvoltage occurrences, the apparatus being included in an arrangement of the above-mentioned sort.

Arrangement for controlling the electric power transmission in a HVDC power transmission system

In one aspect of the teachings herein, a self-commutated current source converter is operated in a manner that compensates for the reactive power consumption and/or harmonics generation of a line-commutated current source converter used in the transfer of electrical power between an AC power system and a DC power system. In this regard, the line-commutated current source converter is operated as a first converter in a hybrid converter apparatus and the self-commutated current source converter is operated as a second converter in the hybrid arrangement. According to one example, the first and second converters are stacked, such that each shares a portion of the DC voltage on the DC side of the hybrid converter apparatus, while in another example, the second converter is not used for power conversion and instead is used solely for compensation with respect to the first converter.

Method and apparatus for transferring power between AC and DC power systems

Multi-terminal HVDC systems and control methods therefore are disclosed. Methods for controlling multi-terminal HVDC systems having a plurality of converter stations may include receiving a plurality of measurements from a plurality of measurement units disposed on the HVDC system, identifying from the measurements a disruption within the HVDC system, monitoring the measurements to identify a steady-state disrupted condition for the HVDC system, calculating a new set point for at least one of the plurality of converter stations, which new set point may be based on the steady-state disrupted condition and the measurements, and transmitting the new set point to the at least one of the plurality of converter stations. In some examples, the HVDC systems may include an HVDC grid interconnecting the plurality of converter stations and a controller communicatively linked to the plurality of measurement units and the plurality of converter stations.

Coordinated control of multi-terminal HVDC systems

It is presented a high voltage DC/DC converter for converting between a first DC connection and a second DC connection. The high voltage DC/DC converter comprises: a first set of DC terminals; a second set of DC terminals); a multiphase transformer device comprising a plurality of primary windings and a corresponding plurality of secondary windings; a first converter arranged to convert DC to AC, comprising a plurality of phase legs serially connected between the first set of DC terminals, wherein each phase leg is connected to an AC connection of a respective primary winding; and a second converter arranged to convert AC from the secondary windings to DC on the second set of DC terminals.

High voltage DC/DC converter

An arrangement transmits power between a DC power line and an AC power line carrying a voltage having a number of phases. The arrangement includes a number of transformers, one for each phase and a number of power transfer modules, one for each phase, connected in series between the DC power line and ground, where each module includes a first branch including series connected converter cells and a second branch including series connected switching elements. The primary winding of a transformer is connected to a corresponding AC phase conductor of the AC power line and the secondary winding is connected between a midpoint of the first branch and a midpoint of the second branch of a corresponding power transfer module.

Arrangement for transmitting power between a DC power line and an AC power line

A cascaded electric power converter and a method of operating a cascaded electric power converter are disclosed. The cascaded converter includes: a converter cell including a cell capacitor and at least one phase leg having at least two electric valves, the at least one phase leg being connected in parallel to the cell capacitor; and a control system for controlling the switching of the electric valves of the at least one phase leg. The control system is configured to, upon detection of a need to by-pass the converter cell, control the switching of the electric valves in a manner so that the cell capacitor is short circuited via a phase leg, so as to obtain a current surge through the phase leg, thereby creating a permanent current path through the converter cell.

Converter cell for cascaded converters and a control system and method for operating a converter cell

A method of controlling a magnitude of an electrical parameter in a power system via a high voltage electron tube. The method includes the steps of measuring the magnitude of the electrical parameter; generating a control signal based on the magnitude of the electrical parameter and on a reference magnitude of the electrical parameter; and switching the high voltage electron tube via the control signal such that the reference magnitude of the electrical parameter is essentially obtained. A control arrangement and a power system is also presented.

Method and control arrangement in a power system

A method, voltage source converter and computer program product for limiting the current in a DC power transmission system are disclosed. The voltage source converter has an AC side and a DC side and a fault current path between these sides. It furthermore includes a control unit and at least one switching unit of a first type provided in the fault current path and that includes a primary switching element together with an anti-parallel secondary controllable rectifying element. Based on a fault being detected in the DC power system when the primary switching elements of the converter are blocked, the control unit changes the control of the controllable rectifying element from acting as a non-controllable rectifying to acting as a controllable rectifying element.

Fault current limitation in DC power transmission systems

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Sodertalje, Sweden

Tomas Lars Jonsson