Abstract: Disclosed is a pumping method of a large-diameter horizontal pressurized long dewatering well for inexhaustible pumping strata. Clay layers and sand soil layers are determined according to construction positions of foundation pits, horizontal holes are drilled in the sand soil layers with a drill rig with simultaneous casing, and after the designed depth is reached, horizontal wells are placed, the horizontal wells are located above the junction of the clay layers and the sand soil layers, and the horizontal wells comprise drain pipes and air ducts, the drain pipes and the air ducts are located at the same elevation, each air duct is located between the two drain pipes, and the air duct is connected with the air pipe of the air compressor to deliver and pressurize, so as to facilitate water in the strata of aquifer to gather into the drain pipes.

Abstract: The present application relates to a direct-drive wind farm parameter tuning method and system considering the interaction between generators, which belongs to the technical field of wind power generation. It solves the problem that the interaction between generators is not considered in the direct-drive wind farm in the prior art, the system stability level cannot be effectively evaluated online, and parameter configuration is unreasonable.

Abstract: A directly-connected high-voltage battery energy storage system (BESS) and a control method thereof are provided. The directly-connected high-voltage BESS includes a battery module, a direct current (DC)/DC converter, a DC bus capacitor, a DC/alternating current (AC) converter, and a grid-side filter inductor. A plurality of battery modules is connected in series to form a battery cluster. The battery cluster is connected in series to the DC/DC converter to form a battery branch, and a plurality of battery branches is connected in parallel to form a battery stack. The battery stack is connected in parallel to the DC bus capacitor and then connected to a DC port of the DC/AC converter to form a battery energy storage submodule. AC ports of a plurality of battery energy storage submodules are connected in series to form a chain-type phase converter.

Abstract: The present invention discloses a method for transmitting parallelization signals of uninterruptible power supplies, which firstly performs a serialization process on parallelization signals by a logic processing unit and then performs synchronous transmission of the parallelization signals of respective node units over a bus. The method for serial transmission of parallelization signals of uninterruptible power supplies according to the invention can be implemented with easy wiring and can achieve a strong anti-interference ability, ensure real time signal transmission over a guaranteed transmission distance and identify conveniently the failure of a parallelization line while satisfying fundamental transmission demands.

Abstract: The invention discloses a power grid fault ride-through device and a method for a doubly fed induction generator.

Abstract: The present invention discloses a method for transmitting parallelization signals of uninterruptible power supplies, which firstly performs a serialization process on parallelization signals by a logic processing unit and then performs synchronous transmission of the parallelization signals of respective node units over a bus. The method for serial transmission of parallelization signals of uninterruptible power supplies according to the invention can be implemented with easy wiring and can achieve a strong anti-interference ability, ensure real time signal transmission over a guaranteed transmission distance and identify conveniently the failure of a parallelization line while satisfying fundamental transmission demands.

Abstract: This invention relates to a method of establishing a master unit in a multi-unit parallel system. Each module with a respective number is connected through a bus, and has a different host-identifying pulse width Ts and a host-releasing pulse width Tw. According to the respective numbers, each module sends its host-identifying pulse to the bus and receives the feedback pulse, and then establishes a master unit among all of modules after comparing the feedback pulse width Tr and the host-releasing pulse width Tw. This method effectively realizes a decentralized controlling strategy for phase synchronization in a parallel inverter system and ensures that only one master unit exists in the parallel system. The connection of the multi-string parallel signal bus is simple, and can be connected in circle to provide the redundancy. Compared with the prior art, it is much simple in structure and flexible in configuration and adjustment, and has more reliability and real-time capability.

Abstract: This invention relates to a method of establishing a master unit in a multi-unit parallel system. Each module with a respective number is connected through a bus, and has a different host-identifying pulse width Ts and a host-releasing pulse width Tw. According to the respective numbers, each module sends its host-identifying pulse to the bus and receives the feedback pulse, and then establishes a master unit among all of modules after comparing the feedback pulse width Tr and the host-releasing pulse width Tw. This method effectively realizes a decentralized controlling strategy for phase synchronization in a parallel inverter system and ensures that only one master unit exists in the parallel system. The connection of the multi-string parallel signal bus is simple, and can be connected in circle to provide the redundancy. Compared with the prior art, it is much simple in structure and flexible in configuration and adjustment, and has more reliability and real-time capability.

Abstract: The present invention relates to a switching synchronization method of parallel converter system, wherein one of converters is the host and the others are slave converters. The host converter includes a first timer and a pulse-transmitting device, and the slave converter includes a second timer, pulse capture device, and a synchronization adjustment. At a fixed time Tk1, the host converter sends a synchronization pulse to the synchronization bus through the pulse-transmitting device; and in the slave converter the second timer records the time Tx of the edge of the synchronization pulse received by the pulse capture device from the synchronization bus.

Abstract: The present invention relates to a switching synchronization method of parallel converter system, wherein one of converters is the host and the others are slave converters. The host converter includes a first timer and a pulse-transmitting device, and the slave converter includes a second timer, pulse capture device, and a synchronization adjustment. At a fixed time Tk1, the host converter sends a synchronization pulse to the synchronization bus through the pulse-transmitting device; and in the slave converter the second timer records the time Tx of the edge of the synchronization pulse received by the pulse capture device from the synchronization bus.