515 results about "Current transformer" patented technology

The invention belongs to a transformer structure, and provides a direct-current transformer, a power transmission system and a control method of the power transmission system in order to solve the technical problems that a three-level circuit topology in a power module in an existing direct-current transformer is large in number of power devices, complex in structure and large in layout and wiring difficulty. Each power module comprises a first-stage circuit, a second-stage circuit, two first direct-current bus capacitors and two second direct-current bus capacitors, the two first direct-current bus capacitors are connected in series to form a first capacitor circuit, and the two second direct-current bus capacitors are connected in series to form a second capacitor circuit. The first-stage circuit comprises two first half-bridge circuits which are connected in series, and the second-stage circuit is a dual-active bridge converter based on a series half-bridge. The number of power devices is remarkably reduced, meanwhile, the layout and wiring difficulty of the whole circuit is simplified, and popularization and application of the direct-current transformer are easier.

The invention relates to a distributed photovoltaic power station main converter and a control method thereof, and belongs to the field of photovoltaic power generation. The main current transformer comprises a T-type three-level current transformer and a Buck-Boost current transformer; the T-type three-level converter comprises three bridge arms, two output capacitors and the like; each bridge arm is provided with four power switch tubes; the two output capacitors are connected in series, and the connection point is called as the midpoint O of the T-type three-level converter. And one end of a direct-current inductor of the Buck-Boost converter is connected with the midpoint O. The T-type three-level converter adopts PI control and a carrier pulse width modulation strategy to realize alternating current side current harmonic wave minimization of the T-type three-level converter; the Buck-Boost converter adopts a PI control method to realize neutral-point potential automatic balance control. The method is small in current harmonic wave, low in cost and simple to control, and can realize quick and automatic balance of the neutral-point potential, thereby effectively coping with the influence of illumination and power grid voltage fluctuation on system control, and realizing quick and stable control of the distributed photovoltaic power station.

The invention discloses a bidirectional hybrid output direct-current transformer and a fault current limiting design method thereof, and the medium-voltage side and the high-voltage side of the bidirectional hybrid output direct-current transformer are respectively composed of three thyristor valve groups and three sub-module bridge arms, and are connected through a medium-frequency transformer. The thyristor valve group is formed by reversely connecting two groups of series thyristors in parallel, and the medium-voltage side sub-module bridge arm and the high-voltage side sub-module bridge arm are respectively composed of NM half-bridge sub-modules and NH half-bridge sub-modules. According to the invention, the sub-module bridge arms with strong control capability are combined with the thyristors and the diode valve groups which are low in cost, low in loss and high in power density, bidirectional power transmission and reliable turn-off of the thyristors can be realized through coordination and cooperation of the middle-voltage side bridge arms and the high-voltage side bridge arms, smooth direct current is ensured, and a filter does not need to be installed. When a short-circuit fault occurs in the outgoing submarine cable, a fault current active suppression strategy is provided, and the scheme can effectively reduce the peak value of the fault current and eliminate the current-limiting inductance.

A transformer substation main equipment fault diagnosis method is characterized in that the method comprises the following steps: collecting transformer substation main equipment multi-modal total data, and obtaining a transformer substation main equipment knowledge graph through word segmentation, entity extraction, relation extraction and knowledge representation processes; extracting a multi-source semaphore related to the current transformer substation main equipment from the multi-modal full-quantity data of the transformer substation main equipment, obtaining a frequent item set in the multi-source semaphore by adopting an association rule mining algorithm, and constructing sensing data information according to the frequent item set; and a graph attention network is utilized to encode the triple in the transformer substation main equipment knowledge graph, a multi-hop reasoning mode is adopted to identify perception data information, and a transformer substation main equipment fault diagnosis result is obtained according to an output result.

The invention relates to the technical field of load regulation, in particular to a transformer load regulation method and device, equipment and a storage medium. The method comprises the following steps: identifying downstream electric equipment of a current transformer, and marking the downstream electric equipment as an electric equipment node; carrying out real-time load monitoring on the electric equipment nodes, and carrying out multi-period load characteristic analysis to obtain a multi-period load curve of each electric equipment node; carrying out multi-time-point discretization processing on the multi-period load curve of each power utilization node, and carrying out node-by-node load change trend analysis to generate load fluctuation trend data of each node; performing current flow direction logic analysis on the nodes of the electric equipment so as to generate node flow direction logic data; and performing topology connection reconstruction based on the node flow logic data, and constructing a node topology distribution network. According to the invention, efficient and balanced transformer load control is realized.

The invention discloses a direct-current transformer power self-balancing control system, which belongs to the technical field of direct-current self-energy taking under a direct-current power distribution network, and comprises a plurality of flyback converters, and a master-slave control framework is formed by taking the actually grounded flyback converter as a master module and taking other flyback converters as slave modules; the main module controls an MOS tube in the main module to be switched on or switched off according to the reference duty ratio; and the slave module controls on or off of an MOS tube in the slave module according to the reference duty ratio and the duty ratio correction. The master module adopts a system output voltage loop to maintain the stability of the system output voltage, the slave module input stage adopts an input grading ring to realize the sharing of the input voltage between flyback modules, and the slave module output stage adopts an output current sharing ring to improve the dynamic response effect of the system. The system can solve the problem of power distribution imbalance caused by inconsistent parameters between flyback modules.

The present invention relates to a system for calibrating a current transformer, aimed at enhancing the accuracy of current measurements. The system comprises a current transformer equipped with a non-volatile memory, configured to store a unique identifying serial number. In conjunction with this, a power meter is set up to communicate with the current transformer. The power meter is fitted with a reading module designed to read the unique identifying serial number from the non-volatile memory of the current transformer. The system also includes a server, connected to communicate with the power meter. The server possesses a database that stores calibration data associated with the unique identifying serial numbers. The server is programmed to receive the unique identifying serial number from the power meter and transmit the corresponding calibration data back to the power meter, enabling precise calibration of the current transformer.

The invention discloses a transformer resistance parameter on-line monitoring method and system based on winding temperature change, and relates to the technical field of transformer winding deformation parameter monitoring method.The method comprises the steps that an oil temperature sensor is used for measuring the oil temperature of a transformer, a 1: 1 simulation model is established, and the relation between winding temperature distribution and winding height is obtained; according to the actual position of an oil baffle plate of a transformer, regionalization analysis is carried out on temperature distribution of a winding, a relational expression between winding temperature distribution and winding height of each region is obtained through curve fitting, an oil temperature sensor is used for obtaining oil temperature values of boundaries of each region, average value operation and summation operation are carried out according to the fitted relational expression, and the oil temperature values of the boundaries of the regions are obtained. And obtaining the current transformer winding temperature. And finally, calculating a resistance parameter changing along with the temperature according to the thermal characteristics of the wire. According to the method, the top oil temperature value is corrected, so that the winding temperature quickly approaches the real situation, and the resistance parameter for monitoring the deformation of the transformer winding is quickly and effectively calculated.

The invention relates to the field of intelligent analysis, and discloses a transformer operation state analysis system and method for transformer substation noise, and the method comprises the steps: collecting the sound signal and noise intensity of a transformer in each region during operation at a set frequency; performing feature extraction on the sound signal of each area to obtain corresponding waterfall spectrogram feature information; inputting the waterfall spectrogram feature information into a pre-trained convolutional neural network model, and outputting a transformer operation state of each region; the transformer operation state of each area in the transformer operation state analysis module is compared with the noise intensity, if the transformer operation state is matched with the noise intensity, it is judged that the current transformer operation state is accurate, and if the transformer operation state is not matched with the noise intensity, it is judged that the current transformer operation state is not accurate, all operation parameters of the transformer are obtained and then analyzed, and transformer operation coefficients are obtained; and updating the current transformer operation state according to the transformer operation coefficient.

The invention relates to the technical field of converters, in particular to a three-phase converter control method and system, a medium and equipment. The method comprises the steps that a main processor transmits sampling original data of a three-phase converter to a first storage area; the coprocessor reads the sampled original data, performs operation to obtain operation result data, and transmits the operation result data to the second storage area; the coprocessor runs at a period higher than the preset control frequency of the main processor, and immediately triggers the operation of the sampled original data after completing the collection of the sampled original data; the main processor performs control loop calculation, reads the operation result data when the newest operation result data is needed, and loads the newest operation result data for updating operation; the main processor runs the control program at the preset control frequency, and the control program triggering time is set in a minimum allowable time window before the control output quantity loading moment. Through the above arrangement, real-time sampling is effectively realized, CPU load is optimized, and the control performance of the converter is improved.

The invention discloses a transformer fault detection method and device, a transformer and a storage medium. The transformer fault detection method comprises the following steps: acquiring hydrogen gas concentration, methane gas concentration, ethylene gas concentration, ethane gas concentration and acetylene gas concentration of dissolved gas in transformer oil, and determining a target transformer fault area corresponding to the dissolved gas according to the acetylene gas concentration; and determining a decision coordinate value corresponding to the dissolved gas according to the hydrogen gas concentration, the methane gas concentration, the ethylene gas concentration, the ethane gas concentration and the acetylene gas concentration, and determining a current transformer fault of the transformer according to the decision coordinate value and the target transformer fault area. According to the method, the dissolved gas in the transformer oil is effectively identified and quantified, the method is suitable for low-cost online fault detection of the transformer, and the accuracy of fault detection and identification of the transformer is improved.

The invention discloses an adaptive virtual impedance-based fault current limiting method for a network-forming converter, and belongs to the technical field of converter control. Comprising the following steps: collecting grid-side voltage, converter-side voltage and converter output current; carrying out current amplitude calculation on the grid-side voltage quantity to obtain a current effective value of the port of the converter; judging whether the current effective value of the current transformer port exceeds a current threshold value of the current transformer; and if yes, self-adaptive virtual impedance is introduced to carry out converter fault current limitation. The resistance part of the virtual impedance is used for suppressing surge current at the beginning of a fault; and the reactance part is used for suppressing the effective value of the fault transient current within the current limiting range. In the fault process, the current virtual impedance value is adaptively changed according to the effective value of the current overcurrent, and the virtual impedance can be automatically quitted after the fault end stage. The method is suitable for fault current suppression of the network-forming converter in various control modes, and has good feasibility and practical value.

The invention discloses a direct-current transformer control method, which relates to the technical field of power electronic control and comprises the following steps of: acquiring operating parameters of a direct-current transformer in real time; the operation parameters at least comprise input side voltage, output side voltage and load current; inputting the operation parameters into a model prediction controller; in the model prediction controller, on the basis of the operation parameters and a preset system model, calculating to obtain a switching device control signal which enables a control target in a future preset time domain to be optimal; a switching device control signal is applied to a switching device of the DC transformer to regulate its output voltage or power. The method has the advantages that the dynamic response speed is increased, the system robustness is enhanced, and multi-target optimization control is realized.

The invention discloses a modular high-voltage direct-current transformer and a control method thereof. The transformer comprises a first energy storage bridge arm, a second energy storage bridge arm and a control switch, the control switch comprises a first group of thyristor valves and a second group of thyristor valves; the first group of thyristor valves comprises an upper thyristor valve and a lower thyristor valve which are respectively used for controlling the charging of the first energy storage bridge arm and the second energy storage bridge arm; the second group of thyristor valves are used for controlling the discharge of the first energy storage bridge arm and the second energy storage bridge arm; the first energy storage bridge arm, the upper thyristor valve and the first diode form a loop, and the second energy storage bridge arm, the lower thyristor valve and the second diode form another loop. According to the invention, the waveform of the bridge arm current is randomly controllable by controlling the bridge arm voltage, the control of the transmission power and the energy balance of the bridge arm are realized, and meanwhile, the active property of the bridge arm can be utilized to realize the reliable turn-off of the soft switch and the thyristor.

The invention relates to a T-connection direct current transformer control method, device and system, a computer readable storage medium and a computer program product. The T-connection direct-current transformer comprises n-phase direct-current conversion modules, and n is larger than or equal to 4. Each phase of DC conversion module comprises a bridge arm formed by connecting a plurality of energy conversion sub-module cascade structures and an electric reactor in series, and two groups of switches, and a common connection end of the two groups of switches connected in series is connected with a first end of the bridge arm; the external connection end of the DC conversion module is used for connecting the high-voltage end, the low-voltage end and the grounding end, and comprises a first end, a second end, a common connection end and a second end of the bridge arm after the two groups of switches are connected in series. The method comprises the following steps: receiving a commutation instruction; in the commutation period, the conduction state of the switch is switched, so that at least an i-phase direct current conversion module is conducted with the low-voltage end at the same moment; 2 < = i < = n-2. By adopting the method, the magnitude of the current which needs to be tolerated by each device can be reduced, so that the T-connection type direct-current transformer meets the requirement of high-capacity application.

The invention discloses an online calculation method and device for broadband impedance of a modular multi-level direct-current transformer, and relates to the field of direct-current transformers, and the method comprises the steps: obtaining the relation of all electric quantities during the steady-state operation of the modular multi-level direct-current transformer based on a circuit topological structure of the modular multi-level direct-current transformer; establishing a power circuit model based on the relation of each electrical quantity during steady-state operation; establishing a control circuit model based on the input and output of the controller group of the modularized multi-level direct current transformer; establishing a small signal impedance model based on the power circuit model and the control circuit model; and calculating the broadband impedance of the modularized multi-level direct-current transformer based on the small-signal impedance model. According to the invention, the broadband impedance of the DC transformer can be calculated on line with high precision and high efficiency in different application scenarios.

The invention relates to a patrol auxiliary decision-making method based on multi-scene perception, and the method comprises the steps: constructing a standard point location label library, mapping the standard point location label library into a patrol point location label library with scene label information, and making a task generation rule under each scene; processing and analyzing the collected data through a deep learning model and scene label information, and identifying a scene where the current transformer substation is located; and generating a patrol task conforming to the scene, automatically executing the patrol task and generating a patrol report, continuously collecting the patrol report, and optimizing the deep learning model through feedback loop. According to the method, the working efficiency of operation and maintenance personnel is improved, the task is automatically created according to the current substation scene, the current substation scene and the real-time state of the patrol host can be quickly analyzed, the optimal patrol plan is generated, and the timeliness and continuity of the patrol task are ensured; according to the real-time environment change, the inspection key point can be rapidly adjusted, the safety of key nodes and lines is preferentially guaranteed, and the continuity and reliability of power supply are ensured.

The invention discloses an enhanced low-voltage topology identification method based on multi-dimensional data combination, and the method comprises the following steps: collecting the physical wiring information of a terminal, and obtaining a wiring database; acquiring terminal position information, and obtaining a community database by using a community division algorithm; collecting electricity utilization characteristic data, and generating an algorithm result database according to the electricity utilization characteristic data by using a topology recognition algorithm; fitting the wiring database, the community database and the algorithm result database to obtain topological data of the current transformer area; and drawing a topological graph of the current transformer area by using the topological data of the current transformer area obtained in the step 2. According to the invention, no unidentified terminal appears in the obtained topological graph, and all terminals are placed at reasonable positions of the topological graph. The virtual nodes obtained through calculation and fitting disappear and are replaced by the actual power cabinet. And each terminal is clearly affiliated to the corresponding power cabinet, so that convenience is provided for finding problems. And the wiring data is associated, so that the drawn topological graph is more vivid and real.

The invention relates to a method and device for evaluating the influence of an internal fault arc on an alternating-current transformer bushing, and computer equipment. The method comprises the steps: carrying out the arc fault simulation through a test platform of the internal fault arc according to a test scheme, and collecting operation parameters in a test process; obtaining a test voltage curve, a test mechanical property curve and a test temperature curve according to the operation parameters; obtaining a corrected mechanical property curve and a corrected temperature curve according to the test current, the test duration, the test voltage curve, and a reference mechanical property correlation curve and a reference temperature property correlation curve corresponding to the alternating-current transformer bushing sample; according to the corrected mechanical property curve, the test mechanical property curve, the corrected temperature curve and the test temperature curve, the influence of the internal fault arc on the alternating-current transformer bushing is evaluated. The method can achieve the comprehensive evaluation of the internal fault arc influence of the sleeve, and improves the accuracy and reliability of an evaluation result.

The invention discloses an underwater new energy power supply system. The power supply system comprises a plurality of new energy power generation modules and a first direct-current transformer which are arranged on the water surface, and a second direct-current transformer and a plurality of charging modules which are arranged underwater, the first direct-current transformer comprises a plurality of first sub-modules, and the low-voltage side of each first sub-module is connected with the corresponding new energy power generation module; the first direct-current transformer comprises a plurality of first sub-modules, the high-voltage sides of the first sub-modules are connected in series, the second direct-current transformer comprises a plurality of second sub-modules, the high-voltage sides of the second sub-modules are connected with the high-voltage sides of the first direct-current transformer after being connected in series, and the low-voltage sides of the second sub-modules are connected in parallel; the input end of each charging module is connected with the low-voltage side of the corresponding second sub-module, and the output end of each charging module is used for being connected with the corresponding underwater electric equipment. According to the scheme, stable electric energy supply can be provided for the underwater electric equipment, and the power supply cost of the underwater electric equipment is reduced.

The invention relates to the technical field of smelting devices, and provides a direct-current submerged arc furnace for smelting, which comprises an operation platform, an electric furnace body, a low smoke hood type furnace cover, a guide rack, a rectifier transformer, a direct-current power supply, a cooling water system and a hydraulic station, and is characterized in that the low smoke hood type furnace cover is erected and mounted at the upper end of the electric furnace body; the low smoke hood type furnace cover is composed of a side wall and a top cover, a graphite electrode clamp is arranged above the low smoke hood type furnace cover, the graphite electrode clamp comprises a connecting shaft, the upper end of the connecting shaft is fixedly connected with the guide rack, and a sliding rod is vertically installed at the upper end of the connecting shaft. An original alternating-current submerged arc furnace holder system is omitted, the electric arc furnace type conductive cross arm stand column is adopted for lifting, lifting is stable, the lifting speed is adjustable and controllable, a traditional alternating-current transformer is designed into a rectifier transformer and a direct-current power source, main electric energy is provided, electric energy loss is reduced, and the effects of saving smelting cost and reducing power grid impact are achieved.

The utility model relates to the technical field of equipment disassembly, and discloses a disassembly tool which comprises a fixed seat, a mounting structure is arranged on the fixed seat, and the mounting structure is suitable for clamping at least part of the fixed seat to the top of an integrated cabinet; a sliding assembly; the hoisting assembly comprises a pulley assembly and a traction piece. According to the disassembling tool, in the field environment, even if a foundation is a stone muddy road surface and the carrying space is limited, transportation and stable installation can be guaranteed, the position of the hoisting assembly can be flexibly adjusted, a converter can be conveniently hoisted at different positions, and the disassembling tool is suitable for various complex field layouts; according to the utility model, the traction piece can be operated manually, so that the problem that an electric tool cannot be used due to inconvenience in on-site electricity taking is avoided, the cost of the tool is greatly reduced, and the tool is convenient to carry and operate.

The invention relates to the technical field of direct-current transformer high-voltage side fault identification and ride-through, and discloses a direct-current transformer high-voltage side fault identification and ride-through method and system, and the method comprises the steps: obtaining a first parameter of a high-voltage side of a target direct-current boosting transformer; acquiring a first fault feature according to the first parameter; the first fault feature is used for identifying a direct-current boosting transformer high-voltage side fault type; and presetting a fault ride-through strategy, and if the first fault feature of any fault type is obtained, starting the fault ride-through strategy. According to the invention, reliable identification and fault ride-through of the DC fault of the collection system can be realized by using the local measurement information of the DC transformer, the method is not influenced by photovoltaic output, the accuracy and efficiency of fault identification are improved, a new idea and method are provided for fault diagnosis of the DC boosting transformer, and the fault diagnosis efficiency of the DC boosting transformer is improved through a control and protection cooperation mode. The accuracy and efficiency of fault recognition are improved, and a new thought and method are provided for fault diagnosis of the direct-current boosting transformer.

The invention relates to a transformer area group optimization method and device, computer equipment and a readable storage medium. The method comprises the following steps: obtaining voltage, current and frequency of each edge node in a to-be-optimized transformer area group, photovoltaic output data of the transformer area group, energy storage charge and discharge state data and electric vehicle charging power data, and presetting various operation constraints set for the transformer area group; and inputting the voltage, the current, the frequency, the photovoltaic output data, the energy storage charge and discharge state data, the electric vehicle charging power data and the various operation constraints into a pre-constructed multi-target optimization model, obtaining optimization strategies meeting the various operation constraints, and performing optimization guidance on the operation of the transformer area group according to the optimization strategies. The transformer area group level multi-objective optimization task is calculated through the cloud high-performance computing cluster, so that an optimization strategy which is more adaptive to the current transformer area group is obtained, edge setting is controlled according to the optimization strategy to execute optimization output, and the load balance and operation robustness of the transformer area group are ensured.

The invention provides a valve assembly equivalent test circuit and a valve assembly full-condition equivalent test method, and the circuit comprises a DC power supply unit, a first phase unit, a second phase unit and a common bridge arm which are connected in parallel. Each of the first phase unit and the second phase unit comprises two bridge arms which are connected in series; a common bridge arm is electrically connected between a connection point of the two serially connected bridge arms in the first phase unit and a connection point of the two serially connected bridge arms in the second phase unit; the common bridge arm is connected in series with the modular multi-level valve assembly to be tested; the direct-current power supply unit is used for charging the two bridge arms in the first phase unit, the two bridge arms in the second phase unit and the common bridge arm respectively; the two bridge arms in the first phase unit, the two bridge arms in the second phase unit and the common bridge arm are all used for generating test current used for testing the modularized multi-level valve assembly. As the bridge arms in the first phase unit and the second phase unit and the common bridge arm are independently adjusted, the test requirements of the direct-current transformer under all working conditions are met.

The invention relates to a substation grounding grid corrosion detection and residual life evaluation method and system. The method comprises the following steps: acquiring a measurement point of a substation grounding grid; calibrating the electrochemical workstation by using a standard impedance source; applying a sine alternating current signal in a preset wide frequency range by using the calibrated electrochemical workstation; selecting a preset number of frequency points, collecting impedance values of each measurement point at different frequency points, and calculating an average value of all the impedance values as an impedance value measurement result of the current measurement point; establishing a Randles equivalent circuit model of the measurement point, fitting the impedance value measurement result of the current measurement point and the impedance value calculation result of the Randles equivalent circuit model by using a nonlinear least square method to obtain an optimal fitting parameter, and calculating the corrosion rate of the transformer substation grounding grid; and measuring the thickness of the current transformer substation grounding grid by using a nondestructive testing technology to obtain the residual life of the transformer substation grounding grid.

The invention provides a high-voltage high-capacity self-coupling direct-current transformer. The high-voltage high-capacity self-coupling direct-current transformer comprises a support capacitor, an energy buffer bridge arm and a converter valve assembly, the support capacitor is used for forming a part of power transmission loop; the energy buffer bridge arm is used for realizing main power transmission and forming the other part of power transmission loop; converting of the transformer is achieved by controlling the input number of the bridge arm sub-modules of the energy buffer bridge arm and trigger signals of the converter valve assembly. Meanwhile, the invention provides a commutation working method and a control method of the transformer. Energy transfer from a low-voltage side to a high-voltage side is realized, the efficiency of the transformer is improved, and energy balance of the energy buffer bridge arm is realized; reliable turn-off and approximate zero-voltage conduction of the converter valve are realized by controlling the input number of the energy buffer bridge arm sub-modules, and two closed-loop modes of direct-current voltage and power control are provided at the same time. High-voltage and high-capacity direct-current transformation is realized, and meanwhile, the semi-control device converter valve is used, so that the device cost is reduced.

The invention discloses a land wind power transmission system, which is used for solving the problems of alternating current collection and transmission such as harmonic resonance and reactive power transmission in the prior art. The land wind power transmission system comprises a wind power sending end unit and a wind power receiving end unit. The wind power sending end unit comprises a direct current transformer and more than two wind turbine generators; a generator-side converter is arranged in each wind generator set and corresponds to one low-voltage circuit breaker; two poles of the direct-current transformer are respectively provided with a direct-current circuit breaker; for each wind power generation set, electric energy generated by the wind power generation set is rectified into first direct current through a machine-side converter, and the first direct current is connected into a direct-current transformer in parallel through a low-voltage circuit breaker to be boosted into second direct current which is sent into a wind power receiving end unit through a bipolar direct-current circuit breaker of the direct-current transformer; the wind power receiving end unit comprises a receiving end converter station, a connection transformer and a starting loop; and the second direct current is subjected to secondary boosting through the connection transformer after being subjected to current conversion through the receiving-end converter station, and is accessed to the alternating-current power grid through the starting loop.

The invention relates to the technical field of flexible direct-current power transmission, and provides an offshore wind power direct-current sending-out system and a starting control method thereof.The system is characterized in that part of wind turbine generators are gathered through an offshore alternating-current gathering bus, then connected to an offshore booster station, connected to a DRU converter valve of a diode uncontrolled rectifying unit and then connected to an offshore direct-current bus through a first switch; an onshore converter valve of the onshore converter station is connected through a direct-current line, and is finally connected to an onshore alternating-current power grid; part of the wind turbine generators are gathered through the offshore direct current gathering bus, then connected to the direct current transformer, then connected to the offshore direct current bus, connected to the land converter valve of the land converter station through a direct current line and finally connected to the land alternating current power grid. According to the offshore wind power direct-current sending-out system, the DRU converter valve and the direct-current transformer are adopted, the DRU does not need to adopt a series / parallel MMC structure, the problem of black start of the DRU converter valve is solved through the power bidirectional flow characteristic of the direct-current transformer, and the direct-current transformer can conduct power transmission.

The utility model relates to the technical field of pension emergency call, and discloses a low-power-consumption SOS emergency button which comprises a button shell lower cover, the top end of the button shell lower cover is fixedly connected with a button shell upper cover through a bolt, and the middle of the button shell upper cover is movably connected with a button body. A main control module and a lorawan communication module are arranged in the lower cover of the button shell, the main control module comprises a power supply part and an alarm button triggering part, the power supply part comprises a battery, a rectifier and a direct-current transformer, and the battery, the rectifier and the direct-current transformer finally generate a DC3V power supply. When the device operates with low power consumption, the current value is 5uA, the farthest communication distance can reach 5-10 kilometers, and the optional working frequency bands are 470, 868, 915 MHz and the like, so that the problem of high power consumption of a traditional SOS emergency button is solved, the communication distance is prolonged, the working frequency band range is enlarged, and the use performance of the SOS emergency button is improved.