General Electric Technology Gmbh

General Electric Company

Kevin J Dyke

David Reginald Trainer

Omar Fadhel Jasim

Colin Oates

Francisco Jose Moreno Muñoz

Sajjad Fekriasl

Colin Charnock Davidson

Nnamdi Okaeme

Colin Donald Murray Oates

Timothy Charles Green

Michael Marc Claude Merlin

Masoud Bazargan

Antonios Tzimas

Jose Maneiro

Guillaume Lucas

Si Dang

The present invention provides methods and apparatus for controlling HVDC power transmission systems so as to increase the effective lifetime of cables carrying the DC power (and particularly the extruded polymer insulation of those cables). The method includes entering a maintenance mode in which the electrical properties applied to the cable are varied so as to facilitate diffusion of space charge accumulation in the extruded polymer insulation.

Control of high-voltage, direct current systems

In the field of high voltage direct current power transmission networks, a method of controlling a converter that includes at least one converter limb which corresponds to a respective phase of the converter, is described. The method includes obtaining a respective AC current demand phase waveform for each converter limb which the corresponding converter limb is required to track, and a DC current demand which each converter limb is also required to track. The method further determining a limb portion current for each limb portion that the limb portion must contribute to track the corresponding required AC current demand phase waveform and the required DC current demand, and providing a limb portion voltage source for each limb portion to achieve the corresponding limb portion current. The method carrying out mathematical optimization to determine one or more optimal limb portion currents and/or provide optimal limb portion voltage sources.

Converter and method of controlling a converter

A voltage source converter of the controlled transition bridge type, having three phase limbs, each phase limb having a high &de director switch (SwSw, Sw) and a low side director switch (Sw, Sw, Sw) connecting a respective DC terminal (DC+, DC&#x2212;) to an AC node for that phase limb. Chain-link circuits for each phase limb comprise a plurality of series connect cells, each cell having an energy storage element that can be selectively connected in series or bypassed. The chain-link circuits are operated in a voltage mode to provide a defined voltage transition at the AC node during a transition between one director switch being turned off and the other director switch being turned on. Chain-link circuits are connected to a common node such that, in use, a current can flow from one phase limb to another via the respective chain-link circuits.

Voltage source converter and control thereof

One circuit includes first and second primary terminals for connection to first and second power transmission lines and a current transmission path extending between the primary terminals and having current transmission path portions separated by a third primary terminal. A first current transmission path portion includes at least one primary switching element connected in series between the first and third primary terminals, the second current transmission path portion includes an energy conversion block connected between the second and third primary terminals, and the energy conversion block includes at least one primary energy conversion element for removing energy from the power transmission lines. The control circuit further includes a converter limb connected across the second and third primary terminals that includes an auxiliary converter. The control circuit further includes a control unit which controls the auxiliary converter to selectively provide a voltage source.

Control circuit

A voltage source converter for interconnecting first and second electrical networks, including first and second terminals for connection to the first electrical network, and a primary converter limb extending between the first and second terminals including first and second primary limb portions separated by a third terminal connectable to the second electrical network. The converter further including a second chain-link converter connected to the third terminal and a control unit configured to selectively operate one or more chain-link modules to generate a discontinuous pulse width modulation voltage waveform. The converter further including a controller configured to selectively operate each chain-link converter to control the configuration of a discontinuous pulse width modulation voltage waveform at the third terminal. The controller including the control unit, and configured to selectively control switching of each primary limb portion into the circuit between the third terminal and one of the first and second terminals.

Modular multilevel converter leg with flat-top PWM modulation, converter and hybrid converter topologies

A voltage source converter () comprises a converter limb (), having primary and secondary limbs connected in parallel between first and second DC terminals (), the primary limb element including first and second primary limb element portions () separated by a third terminal (), being connectable to an AC electrical network (), each primary limb element portion () including at least one primary switching element (), the secondary limb including first and second secondary limb element portions () separated by a junction (), and including a DC side chain-link converter (), and a connection interconnecting the third terminal () and the junction () wherein the voltage source converter () further includes a control unit () controlling the switching of the respective switching elements.

Converter

A voltage source converter includes a converter limb having limb portions separated by an AC terminal and extending between DC terminals, each limb portion including a primary switching element to switch the limb portion into and out of circuit. The converter further includes an auxiliary limb. The primary switching element of each limb portion is switchable to switch the auxiliary limb into and out of circuit with the corresponding limb portion. The converter further includes a control unit to, in one mode, inject a circulation current that flows in one direction in one of the limb portions and minimize a current flowing in the opposite direction in that limb portion. Each primary switching element switches the respective limb portion into or out of circuit following the minimization of the limb portion current by the circulation current.

A control circuit comprising: first and second terminals for respective connection to first and second power transmission lines; a current transmission path extending between the first and second terminals and having first and second current transmission path portions separated by a third terminal, either or both of the first and second current transmission path portions including at least one module, the or each module including at least one energy storage device; an auxiliary terminal for connection to ground or the second power transmission line; an energy conversion block for removing energy from the power transmission lines, the energy conversion block extending between the third and auxiliary terminals such that the energy conversion block branches from the current transmission path, the energy conversion block including at least one energy conversion element; and a control unit which selectively removes the or each energy storage device from the current transmission path.

Growing community of inventors

South Gloucestershire, United Kingdom

Kevin J Dyke