Nr Electric Co., Ltd

Nr Engineering Co., Ltd

Nr Electric Engineering Co., Ltd.

Nanjing Tech University

Jiangsu Academy of Agricultural Sciences

Yangzhou University

Yu Lu

Yunlong Dong

Jie Tian

Haiying Li

Zhaoqing Hu

Nannan Wang

Gang Li

Jiudong Ding

Jiang Lu

Dongming Cao

Ke Wang

Chongxue Jiang

Yongping Wang

Tiangui Jiang

Lei Pan

Haibin Liu

Shunke Sui

Defeng Qiu

Wenqiang Zhao

Jiacheng Wang

Hui Wang

Quanrong Shen

Ruhai Huang

Jianyang Lian

Min Li

Gang Shen

Xiang Ling

Chao Liu

Yeyuan Xie

Minglian Zhu

Xin Huang

Ming Hu

Jibo Hou

Yadong Feng

Xiaoyan Zhang

Xinbao Wang

Baoli Chang

Mingsheng Du

Hang Wang

Peng Xiao

Yanhong Zhao

Bihua Deng

Jinqiu Zhang

Jianmin Xiao

Xiaoxin Zuo

Chuanjun Bai

Jianchun Li

Xianlai Hu

Guorong Shen

Zhenxia Shao

Xinyan Jiao

Xiuda Ma

Baoshun Zhang

Zhiwei Sun

Jiyang Sun

Changjiang Kou

Hua Xie

Zhengguang Wu

Rongxue Fan

Aihong Kang

Qingsheng Li

Xiaolei Zhu

Fang Lv

Haibin Lu

Yizhe Lin

Tieqiang Ren

Feixiang Wu

Changjiang Zhan

The present invention discloses a mobile energy storage internet system. The mobile energy storage internet system comprises distributed energy harvesting devices, mobile cold storage/heat storage devices, an energy system dispatching and monitoring center, and cold supply/heat supply terminals. The distributed energy harvesting devices are used for harvesting industrial waste cold energy/heat energy. The energy system dispatching and monitoring center is used for monitoring the residual energy of the distributed energy harvesting devices and the energy demand of the cold supply/heat supply terminals respectively, and mobilizing the mobile cold storage/heat storage devices to the distributed energy harvesting devices to store residual energy or to the cold supply/heat supply terminals to release the stored residual energy. The mobile energy storage internet system disclosed by the present invention can make full use of various waste industrial residual energy, and nest electricity of renewable energy power stations and nuclear power stations, realizes long-distance cold supply and heat supply without pipe network, and reduces energy consumption in construction industries.

Mobile energy storage internet system

Disclosed is a method for preparing bittern-carbonization synergistic reinforced recycled aggregate, including the following steps: spray pretreatment: performing alternate spraying on recycled aggregate with bittern and lime milk at intervals for many times at 4-70° C. and a pressure of 0.05-0.6 MPa; carbonization reinforcement: introducing waste gas containing carbon dioxide for a retention time of 4-8 h after the recycled aggregate is allowed to stand for 2-4 h; and rinsing and air drying: removing soluble impurities on a surface of the recycled aggregate by rinsing in water, and performing air-drying on the recycled aggregate to obtain bittern-carbonization synergistic reinforced recycled aggregate. According to the present disclosure, the effective reinforcement of recycled aggregate at normal temperature and pressure in a short time is realized, and the method is simple in process and is convenient in operation.

Method for preparing bittern-carbonization synergistic reinforced recycled aggregate

The invention relates to an island converter overload limit method and device for a bipolar flexible DC transmission system, and belongs to the field of DC transmission. During stable island operation, both bipolar converters adopt a voltage-frequency droop control strategy; and once it is detected that one converter is overloaded, the control mode of the overloaded converter is automatically switched to active-wattless power control from voltage-frequency droop control to fulfill an overload limit function. The method effectively avoids an overload of the bipolar flexible DC transmission system under island operation, effectively maintains the AC voltage and frequency stable, and has important guiding significance for applying island systems to DC power grids.

Converter control method and device

Disclosed are a control method and system for a parallel converter system, including a common AC voltage controller and a separate current controller for each converter; the AC voltage controller generates an active current, a wattless current, and a system voltage phase reference value and, by means of communication, sends same to the current controller of each converter in island control mode to be a converter control signal; the active and wattless current outputted by each converter, along with the corresponding current reference value, accomplish the objective of the parallel converter system collectively controlling the amplitude and frequency of an AC bus voltage. The method and system are highly reliable and effectively ensure the synchronization of a plurality of converters.

Control system and control method for parallel converter system

During initiation under an isolated island condition, the amplitude of a voltage reference wave output generated by a flexible DC transmission control and protection system is in a segmented mode, wherein a first segment of the reference wave amplitude begins at zero or a fixed value Uand rapidly increases to UkV at a rate of a kV/s, avoiding a low output voltage reference wave and high error and harmonic content of a sampled voltage and current. A second segment increases to UkV at a rate of &#x3b2; kV/s, a third segment increases to UkV at a rate of &#x3b3; kV/s, and the Nsegment increases to a rated voltage of UkV at a rate of &#x3b5; kV/s, thereby achieving non-disturbance and shockless initiation of a flexible DC transmission system under an isolated island condition.

Method for initiating flexible DC transmission system under isolated island condition

Disclosed in the present invention is a voltage and current control method for a direct-current transmission system. The method comprises: calculating a DC voltage reference value of a voltage source converter of a DC voltage control end, on the basis whether a direct-current voltage end of a direct-current pole of a direct-current transmission system substantially controls a direct-current voltage; using &#xbd; of the calculated direct-current voltage reference value of the voltage source converter as a bridge arm voltage direct-current bias, calculating a difference between the direct-current voltage reference value of the voltage source converter and a measured direct-current voltage value, and inputting the difference into a direct-current voltage control outer loop of the voltage source converter to perform closed-loop control, so as to control the direct-current voltage or the direct current of the direct-current pole. Correspondingly, also provided is a voltage and current control device for the direct-current transmission system. By the means of the present invention, the direct-current voltage and the direct current of the direct-current transmission system provided with the voltage source converter can be effectively controlled.

Voltage and current control method and device for direct-current power transmission system

A DC voltage coordination control method is applied to a multi-terminal VSC-HVDC power transmission system or a VSC-HVDC power grid system. When a lower-level control is used in the active power control mode, the active power reference value of the converter is generated according to the converter DC voltage and the converter DC voltage active power curve; it also includes an upper-level control to adjust the control mode and active power setting value of the lower-level control to ensure the steady-state performance of the system. This method has low dependence on communication, avoids the problem that the fixed slope and margin cannot meet all operating conditions, and is suitable for large-scale VSC-HVDC systems, and has scalability.

Direct current voltage coordination control method

A coordinated control method for series voltage source converter valve groups comprises: allocating a total direct-current voltage reference value or a total active power reference value at the end where a direct-current electrode series voltage source converter valve group is located according to the total number of voltage source converter valve groups in series; for a direct-current voltage control end, controlling the direct-current voltage of each valve group according to the assigned direct-current voltage reference value for each valve group; for an active power control end, controlling the active power of each valve group according to the assigned active power reference value for each valve group and based on adding the active power compensation amount of the valve group which has voltage equalization effects on the valve group. Correspondingly, also providing a coordinated control device for series voltage source converter valve groups. The direct-current voltage equalization of each valve group in operation of the direct-current voltage control end or the active power control end of the series voltage source converter valve group is achieved.

Coordinated control method and device for series voltage source converter valve group

A method and apparatus for suppressing the impact of a compensator on line distance protection is provided, wherein the method comprises: obtaining a first current of a line connected to a compensator or series converters in the compensator, and a first voltage of a bus connected to the compensator or the line connected to the compensator; exiting the series converters and series transformers if the first current is greater than a preset current threshold and a duration is greater than a first preset time threshold; exiting the series converters and the series transformers if the first voltage is less than or equal to a preset voltage threshold and duration is greater than a second preset time threshold set the output voltage of the series converters to zero, and if a second current of an element corresponding to the first current meets conditions which the first current needs to meet; and otherwise, canceling the setting of the output voltage of the series converters to zero and obtaining a first current if a second voltage of the line corresponding to the first voltage is greater than the preset voltage threshold and the duration is greater than a third preset time threshold.

Method and apparatus for suppressing impact of compensator on line distance protection

A fault switch configuration and clearing method in a flexible DC converter station, the flexible DC converter station is configured with a grid side switch and a valve side phase-split switch in the converter station. When a fault occurs, a faulty phase and a non-faulty phase are detected and identified by means of differential protection or low voltage overcurrent. An alternating current zero crossing condition is created by means of firstly turn off the non-faulty phase valve side phase-split switch and the grid side switch, thereby cutting off the faulty phase, disconnecting the connection between a power supply and a fault point, and achieving the clearing for faults. The described fault-clearing method is simple and practical, highly reliable, and connection between the fault point and the power supply is quickly and effectively cut; converter station equipment is effectively protected, and further expansion of the fault is avoided.

Fault switch configuration and clearing method in flexible DC converter station

Provided in the present invention is a direct current power grid voltage control method, dividing control of a direct current power grid voltage into three processes, namely natural voltage regulation, first voltage regulation and second voltage regulation; the converter stations in the direct current power grid are divided into three types, namely power regulation converter stations, auxiliary voltage regulation converter stations, and voltage regulation converter stations, on the basis of whether the converter station has a voltage regulation capacity, the power regulation converter stations operating in a fixed power control mode, the voltage regulation converter stations operating in a fixed voltage control mode or an auxiliary voltage control mode, and the auxiliary voltage control converter stations operating in the auxiliary voltage control mode; all the converter stations in the direct current power grid participate in natural voltage regulation, the auxiliary voltage regulation converter stations and the voltage regulation converter stations participate in first voltage regulation, and the voltage regulation converter stations participate in second voltage regulation; by means of a combination of the three voltage regulation processes, accurate control of the direct current voltage can be implemented in a steady state, and direct current voltage change can be suppressed in a transient state.

Direct current power grid voltage control method

Provided is an on-line input and quit control method for a voltage-source converter unit. The method achieves the on-line input of a voltage-source converter unit by means of performing steps, such as charging control, deblocking transfer control and operation adjustment control, on a voltage-source converter to be input, and achieves the on-line quitting of the voltage-source converter unit by means of performing steps, such as direct-current voltage reduction control, bypass transfer control and converter blocking control, on a voltage-source converter to be quit. Correspondingly, provided is an on-line input and quit control device for a voltage-source converter unit, which can achieve the on-line steady input and quitting of a voltage-source converter in a series-type hybrid direct-current power transmission system or a series-type flexible direct-current power transmission system, without affecting the normal and stable operation of other already running converters.

On-line input control method, on-line input and quit device for voltage-source converter unit

A thermostable formula comprises the following components in percentage by mass: 1% to 5% raffinose, 5% to 10% maltose, 15% to 30% saccharose, 1% to 5% lactose, 1% to 5% glucose, 0.1% to 1.5% polysorbate 80, 0.1% to 0.5% polyethylene glycol 8000, 0.5% to 3% tyrosine, 3% to 6% silk fibroin, and the balance of water for injection. It further discloses a room-temperature-preserved live classical swine fever vaccine and a preparation method thereof, wherein the live classical swine fever vaccine is obtained by mixing the thermostable formula with a live classical swine fever virus solution and then carrying out gradient vacuum drying. The vaccine prepared according to the present invention has a dried foam appearance and presents a glass-layer like structure under a scanning electron microscope, has a glass transition temperature up to more than 50&#xb0; C.

Heat-resistant protective agent, room-temperature-preserved live classical swine fever vaccine, and preparation method and application thereof

A sub-module based hybrid converter is provided. By setting a half-controlled charging link of changing full bridge sub-modules from a blocked state to a half-blocked state one by one in a charging process, and raising the voltages of half bridge sub-modules to reach the starting point of a half bridge sub-module based self-powered supply in an uncontrolled stage of the half bridge sub-modules, the starting point of the sub-module based self-powered supply is increased, and the design difficulty of the sub-module based self- powered supply is reduced. The present invention also includes another charging method for a sub-module based hybrid converter.

Charging method for sub-module based hybrid converter

A method and apparatus for controlling a hybrid direct-current (DC) transmission system. The method comprises: adjusting the total number of inserted sub-modules of a modular multi-level converter and the polarity of an output level of the inserted sub-modules in real time, according to a DC voltage of a rectifier station at other end; or adjusting the total number of inserted sub-modules of a modular multi-level converter and the polarity of an output level of the inserted sub-modules in real time, according to the magnitude of a DC current or DC power; or adjusting the total number of inserted sub-modules of a modular multi-level converter and the polarity of an output level of the inserted sub-modules in real time, according to both the magnitude of the DC current and the DC voltage of the rectifier station at the other end. The method can effectively control the DC voltage and the direct current of a hybrid DC transmission system, avoiding the power transmitting breakdown.

Method and apparatus for controlling hybrid direct-current transmission system

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Jiangsu, China

Yu Lu