Nr Electric Co., Ltd

Nr Engineering Co., Ltd

Bing Yang

Dongming Cao

Wei Shi

Taixun Fang

Yeyuan Xie

Wenjie Wang

Wei Lv

Yu Wang

Tao Wang

Wei Lu

Hao Yang

Bin Liu

Lele Li

A closing control method for a high-voltage DC circuit breaker. The method comprises: closing breaking units of the transfer branch () group by group, then closing the main branch (), and finally open the transfer branch. During the process of closing the breaking units of the transfer branch group by group, determine whether there is a fault in the power transmission system after closing current breaking unit group. if there is no fault, proceed to close the next breaking unit group until all breaking unit groups are closed before proceeding to the next step; if there is a fault, all the breaking units that have been closed are opened and the closing operation is ended. The method can pre-charge the power transmission system during the closing process of the high-voltage DC circuit breaker, and lower the overvoltage and system oscillation caused by the closing operation.

Closing control method for high-voltage direct-current circuit breaker

A bridge-type circuit comprises a H-bridge switch module and a buffering and reclosing module. The H-bridge switch module comprises four power semiconductor switch devices. Every two of the four power semiconductor switch devices are connected in series in the same direction to form a bridge arm, and the two bridge arms are further connected in parallel. Middle points of the two bridge arms respectively serve as an input terminal and an output terminal. The buffering and reclosing module is connected in parallel with the two bridge arms of the full bridge module. Also provided are a direct current breaking device formed by connecting the above bridge-type circuits in cascade and a control method thereof. The direct current breaking device is provided with the buffering and reclosing module, such that line voltage fluctuation generated during a reclosing operation is small.

Bridge-type circuit, and direct current breaking device and control method thereof

A direct current switch-off device comprises an on-state current branch circuit and a current commutating and breaking unit which are connected in parallel. The on-state current branch circuit has a mechanical switch (S) and a current transfer module which are connected in series. The current commutating and breaking unit comprises a bridge-type branch circuit and a current-breaking branch circuit. The current-breaking branch circuit and two bridge arms of the bridge-type branch circuit are connected in parallel. The current-breaking branch circuit comprises a nonlinear resistor (RI) and a valve group consisting of fully-controlled devices connected in series. The nonlinear resistor (RI) and the valve group are connected in parallel. Two ends of each fully-controlled device in the valve group are connected in parallel with a buffering and reclosing circuit.

Direct current switch-off device and control method thereof

An apparatus for breaking a line bidirectional current and a control method therefore. The apparatus comprises a breaking current branch circuit and an on-state current branch circuit, the breaking current branch circuit comprises one nonlinear resistor being connected in parallel to one first power semiconductor device, or one nonlinear resistor being connected in parallel to at least two first power semiconductor devices mutually connected in series; and the on-state current branch circuit comprises at least one bidirectional power semiconductor switch being connected in series to at least one high-speed isolation switch. The apparatus also comprises a bridge-type branch circuit. An apparatus for breaking a line bidirectional current, thereby greatly reducing costs of the apparatus and reducing difficulty in device layout, mounting and wiring of the apparatus on the premise of ensuring a breaking speed that is quick enough and a low loss.

Apparatus for breaking line bidirectional current and control method thereof

An apparatus for limiting a current of a line or breaking a current, and a control method thereof are disclosed. The apparatus includes a current breaking branch () and a bridge branch. The bridge branch includes two bridge arms formed by four identical current commutation branches. Every two of the four current commutation branches are connected in series, and the formed two bridge arms are then connected in parallel. The two bridge arms are both connected in parallel to the current breaking branch, and middle points of the two bridge arms are separately connected to two ends of a line. Each current commutation branch includes at least one high-speed isolation switch () and at least one bidirectional power semiconductor switch () that are connected in series. The apparatus can turn off currents in two directions.

Apparatus for limiting current of line or breaking current, and control method thereof

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Jiangsu, China

Bing Yang