Abb Schweiz Ag

Abb Power Grids Switzerland Ag

Hitachi Energy Ltd

Hitachi Energy Switzerland Ag

Siemens Aktiengesellschaft

XiaoBo Yang

Kai Liu

Dong Li

ChunMing Yuan

Dawei Yao

Chao Yang

Xing Huang

Guoxing Fan

Bertil Berggren

Jiuping Pan

Ritwik Majumder

Frans Dijkhuizen

HaiLian Xie

Sheng Zong

Francisco Canales

Bernt Bergdahl

Kuenfaat Yuen

Tongzhou Wang

Chuanyu Zhang

Mats Andersson

David Schaeffer

Neil-QiNan Li

Yaolei Kang

Jianyong Zhang

A voltage source converter (VSC) system of a high-voltage direct current (HVDC) system is disclosed. The system includes a number of line-commutated converter (LCC) transformers. Each LCC transformer is operable to transform alternate current (AC) voltage. A number of VSC converter units are connected in series and coupled to the plurality of LCC transformers. Each VSC converter unit is operable to convert between the AC voltage and direct current (DC) voltage. A bypass breaker is connected in parallel with at least one of the VSC converter units and operable to be closed to bypass the at least one VSC converter unit.

UHVDC converter transformer re-usage for LCC to VSC upgrade

Embodiments of a modular direct current interconnection device (MDCID) include at least three operation branches, at least one transient branch, and a local controller. Each of the operation branches includes a first terminal coupled to a common node and configured to transmit DC current in a normal mode. The transient branch is coupled between second terminals of different ones of the at least three operation branches and configured to provide a transient DC current path in a fault clearance mode. The local controller is coupled to the operation branches and the transient branch, and the local controller is configured to control operation of the operation branches and the transient branch.

Modularized DC interconnection device and system thereof

A power converter includes a power conversion circuit having a first terminal set and a second terminal set, configured to convert power input via one of the first terminal set and the second terminal set and output the converted power via the other of the first terminal set and the second terminal set; a measurement unit; a controller configured to control the power conversion circuit to generate a voltage/current waveform travelling along the first network with a power supplied by a second power source linked to the second terminal set of the power conversion circuit in response to a condition that a change rate of the measurement of the voltage/current exceeds a threshold; and locate a fault on the first network. The power conversion circuit can be re-used for different modes of operation either for power transmission under normal condition or for fault location under fault condition.

Power converter and control method therefor

Embodiments of present disclosure relates to a modular interconnection device (MID) and an electrical network system. The MID comprises a modular port assembly, a node, a converter and a local controller. The modular port assembly is configured to transmit alternating current and/or direct current. The node is coupled to an AC source via a first switch and the modular port assembly. The first switch is configured to selectively disconnect the modular interconnection device from the AC source. The converter is coupled to the node via a second switch and coupled to a DC source via a third switch. The converter is configured to convert the AC current into DC current or convert DC current into AC current. The local controller is coupled to the first, second and third switches and configured to control operation of the first, second and third switches.

Modularized interconnection device and system thereof

Unique systems, methods, techniques and apparatuses of a distribution system are disclosed. One exemplary embodiment is an alternating current (AC) distribution system including a first substation including a first transformer and a protective device; a first distribution network portion coupled to the first transformer; a second substation; a second distribution network portion; a DC interconnection system coupled between the first distribution network portion and the second distribution network portion; and a control system. The control system is structured to detect a fault in the first transformer or the transmission network, isolate the first distribution network from the fault, determine a set point of the DC interconnection system, and operate the DC interconnection system using the set point so as to transfer a portion of the MVAC from the second distribution network portion to the first distribution network portion.

Transformer isolation response using direct current link

A method, system and apparatus for operating a hydraulic turbine. A speed adjustment quantity for the hydraulic turbine and a corresponding change in flow quantity are obtained. A rotation speed of the hydraulic turbine is adjusted based on the speed adjustment quantity. A change ratio of the flow quantity with regard to the speed adjustment quantity is determined based on the speed adjustment quantity and the corresponding change in flow quantity. An adjustment manner in which the rotation speed is further adjusted is determined based on the determined based on the determined change ratio of flow quantity. An adjustment manner in which the rotation speed is further adjusted is determined based on the determined change ratio of flow quantity. It enables the hydraulic turbine to track a maximum efficiency operation point under a given power order and water head in real time at a low cost.

Method, system and apparatus for operating a hydraulic turbine

An objective of the invention is to provide a bidirectional power valve for current occurring in a high voltage DC conductor, control method therefor, hybrid multi-terminal HVDC System using the same. The bidirectional power valve includes a first power diode arrangement of a first conducting direction, a second power diode arrangement of a second conducting direction; a mechanical disconnector, being connected with the second power diode arrangement in series; wherein: the first power diode arrangement and the series-connected second power diode arrangement and the mechanical disconnector are connected in parallel; and the first conducting direction of the first power diode arrangement and the second conducting direction of the second power diode arrangement are opposite to each other. The current commutation and re-commutation can be achieved with less requirement of the timing accuracy of switching event which makes the usage of a mechanical disconnector and power diode feasible. This will then result in a significant reduction of cost and power transfer losses.

Bidirectional power valve and control method therefor and hybrid multi-terminal HVDC system using the same

Systems, methods, techniques and apparatuses of feeder line fault response are disclosed. One exemplary embodiment is a method for operating an alternating current (AC) distribution network including a first feeder line, a second feeder line, and a third feeder line. The method includes isolating a faulted portion of the first feeder line from a healthy portion of the first feeder line; closing a tie switch coupled between the healthy portion and the second feeder line in response to isolating the faulted portion from the healthy portion; determining the second feeder line is experiencing an overload condition after closing the tie switch; and transferring AC power including transferring AC power using a direct current (DC) interconnection system coupled to the third feeder line effective to remove the overload condition from the second feeder line.

Feeder line fault response using direct current interconnection system

A DC to DC converter with intermediate conversion into AC power, including: a transformer having a primary winding and a secondary winding; a first DC to AC conversion circuit having its AC terminals coupled with the primary winding of the transformer; a first AC to DC conversion circuit having its AC terminals coupled across a first tap and a second tap of the secondary winding of the transformer; a second AC to DC conversion circuit having its AC terminals coupled across a third tap and a fourth tap of the secondary winding of the transformer, wherein the first tap and the second tap are arranged between the third tap and the fourth tap along the secondary winding of the transformer; and at least one first power switch, being arranged between one of DC terminals of the first AC to DC conversion circuit and one of DC terminals of the second AC to DC conversion circuit. By having the solution as above, the DC output voltage may be changed between two levels by operating only one power switch. Because a power switch is more expensive than a multiple of power diodes, by reducing the number of power switches responsible for changing the level of DC output voltage, it is helpful for decreasing the cost and complexity of control. Besides, the power loss can be decreased due to switching of less power switch.

DC to DC converter

The application relates to a DC to DC converter and control method thereof. The DC to DC converter includes a first converter circuit, a second converter circuit, a transformer having a primary winding and a secondary winding, a first resonant tank having a first capacitive element and a first inductive element, and a second resonant tank having a second capacitive element and a second inductive element. The first capacitive element and the first inductive element are coupled between the first converter circuit and the primary winding of the transformer; the second capacitive element and the second inductive element are coupled between the second converter circuit and the secondary winding of the transformer. During power transfer from the second converter circuit to the first converter circuit, a first plurality of first power-semiconductor-devices of the first converter circuit are operable to charge the first capacitive element during a first half cycle of a switching period; and a second plurality of the first power-semiconductor-devices of the first converter circuit are operable to provide an output voltage comprising an voltage across the primary winding of the transformer and the voltage of the first capacitive element superimposed thereon. This provides step-up gain for the backward direction, the first converter circuit operating in double voltage rectification manner and the second converter circuit working in the conventional full-bridge modulation with switching frequency fixed substantially at the resonant frequency.

DC-DC converter and control method

The invention relates to a bidirectional DC-DC converter with intermediate conversion into AC power, including: a DC-AC conversion circuit using a plurality of MOSFETs; an AC-DC conversion circuit using a plurality of power diodes; a transformer; a pair of switches, one of which being inserted in series between a DC terminal of the DC-AC conversion circuit and the AC-DC conversion circuit and the other of which being inserted in series between another DC terminal of the DC-AC conversion circuit and the AC-DC conversion circuit; and a controller being adapted for turning on the pair of switches such that the plurality of power diodes of the AC-DC conversion circuit are reverse-biased where the AC power is transferred in the forward direction and turning off the pair of switches where the AC power is transferred in the backward direction.

Bidirectional DC-DC converter and control method therefor

The application relates to a system for charging a battery of an electrical vehicle. The electrical vehicle charging system of the present application is helpful for decreasing the converter capacity while maintaining the charging capacity and electrical vehicles with various nominal voltages can be charged simultaneously. In one aspect the system for charging an electrical vehicle includes: a plurality of central converters, at least one switch electrically connected to the central converters, at least one transformer electrically connected to an external AC power supply, at least one distributed converter for supplying at least one distributed DC voltage with a level below that of the central converter, and a controller connected to the at least one switch.

Growing community of inventors

Beijing, China

XiaoBo Yang