Abstract:
A voltage source converter (10) for use in three-phase high voltage DC power transmission and reactive power compensation. The voltage source converter (10) comprises three converter limbs (12,14,16) connected in a bridge circuit arrangement wherein each of first and second converter limbs (12,14) includes a multilevel converter (18) and a third converter limb (16) includes a capacitor (20) on each side of a series AC phase connection (22). The multilevel converters (18) are controllable to synthesize waveforms at series AC phase connections (24,26) of the first and second converter limbs (12,14).
Abstract:
A voltage source converter for use in high voltage DC power transmission and reactive power compensation. The voltage source converter comprises at least one converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal for connection in use to an AC network.The or each converter limb defines first and second limb portions, each limb portion including at least one switching element connected in series with a chain-link converter between a respective one of the first and second DC terminals and the AC terminal. The switching elements of the first and second limb portions is operable to switch the respective chain-link converters in and out of circuit between the respective DC terminal and the AC terminal. The chain-link converters are operable to generate a voltage waveform at the AC terminal.
Abstract:
A circuit for a hybrid voltage source converter suitable for high voltage DC power transmission and reactive power compensation. The circuit comprises an assembly of electrically interconnected elements (Elements 1 to 20) including a plurality of first elements (Elements 1 to 6) and a plurality of second elements (Elements 7 to 20). Each of the first and second elements is configurable to be bypassed, to be disconnected or to include a circuit arrangement of one or more electronic components to construct, in use, a hybrid voltage source converter including at least one first element and at least one second element and in which the circuit arrangement included in the or each first element is different to the circuit arrangement included in the or each second element.
Abstract:
A multilevel voltage source converter for high voltage DC power transmission and reactive power compensation. The voltage source converter includes at least one phase element including a plurality of semiconductor switches to interconnect a DC voltage and an AC voltage. The voltage source converter also includes at least one auxiliary converter to act as a waveform synthesizer to modify the DC voltage presented to the DC side of the phase element.
Abstract:
A multilevel voltage source converter for high voltage DC power transmission and reactive power compensation. The voltage source converter includes at least one phase element including a plurality of semiconductor switches to interconnect a DC voltage and an AC voltage. The voltage source converter also includes at least one auxiliary converter to act as a waveform synthesizer to modify the DC voltage presented to the DC side of the phase element.
Abstract:
A method for reversing accounting distortions of financial information, comprising the steps of obtaining a set of financial information regarding an entity, the financial information including accounting distortions and notes detailing said accounting distortions; analyzing the financial information and notes to determine an accurate economic model; and using said accurate economic model to automatically determine the true profitability of an entity and comparatively value a plurality of expectations with respect to the financial information.
Abstract:
A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprises a plurality of switching elements interconnecting in use a DC network and one or more AC networks, the plurality of switching elements being controllable in use to facilitate power conversion between the AC and DC networks, wherein in use, the plurality of switching elements are controllable to form one or more short circuits within the power electronic converter so as to define one or more primary current flow paths, the or each primary current flow path including a respective one of the AC networks and the power electronic converter and bypassing the DC network.
Abstract:
A voltage source converter is used in high voltage direct current power transmission and reactive power compensation. The voltage source converter includes first and second DC terminals for connection in use to a DC network, three phase elements and at least one auxiliary converter connected between the first and second DC terminals, each phase element including a plurality of primary switching elements and at least one AC terminal for connection in use to a respective phase of a multi-phase AC network, the plurality of primary switching elements being controllable in use to facilitate power conversion between the AC and DC networks, the or each auxiliary converter being operable in use to act as a waveform synthesizer to modify a first DC voltage presented to the DC network so as to minimize ripple in the DC voltage.
Abstract:
A DC voltage source converter for use in high voltage DC power transmission comprising at least one chain-link converter connected between first and second DC terminals. The or each chain-link converter includes a chain of modules connected in series and each module including at least one pair of semiconductor switches connected in parallel with an energy storage device. The or each chain-link converter is operable when DC networks are connected to the first and second DC terminals to control switching of the modules to selectively charge or discharge the energy storage device of one or more of the modules, as required, to offset any difference in the DC voltage levels of the DC networks.
Abstract:
A voltage source converter for use in high voltage DC power transmission and reactive power compensation. The voltage source converter comprises at least one converter limb including first and second DC terminals for connection in use to a DC network and an AC terminal for connection in use to an AC network.The or each converter limb defines first and second limb portions each limb portion including at least one switching element connected in series with a chain-link converter between a respective one of the first and second DC terminals and the AC terminal. The switching elements of the first and second limb portions is operable to switch the respective chain-link converters in and out of circuit between the respective DC terminal and the AC terminal. The chain-link converters are operable to generate a voltage waveform at the AC terminal.