41results about How to "Ensure continuity of power supply" patented technology

The invention provides an on-line three-phase load unbalance processing method suitable for a low-voltage distribution network. The on-line three-phase load unbalance processing method comprises the following steps of: monitoring three-phase load by three-phase load monitoring units on the low voltage side of a distribution transformer, and transmitting monitoring data to three-phase load unbalance monitoring units of the distribution transformer; judging whether the three-phase load unbalance exceeds a standard value or not by the three-phase load unbalance monitoring units of the distribution transformer; if the three-phase load unbalance exceeds the standard value, transmitting signals to an on-line load phase modulation control unit by a communication unit; judging whether the three-phase load unbalance of the distribution transformer is caused by the three-phase load unbalance of a main low-voltage circuit or not by the on-line load phase modulation control unit; and if so, setting an on-line load phase modulation strategy according to the monitoring data of the load monitoring units of branches of three phases of the main low-voltage circuit, sending a control command to an on-line load phase modulation switch combination unit by an on-line load phase modulation judging and controlling unit, and switching the load phases of the branches of users so as to realize the on-line three-phase load unbalance processing.

The invention relates to a low voltage load online phase modulation device and a phase modulation method thereof. According to the invention, optimization selection is performed to phase sequence state combination of electric load of users in a power distribution area, and then the electric load of the users is switched freely among phases A, B and C via a controllable switch, so that loads of the three phases of the power distribution area can be balanced. The low voltage load online phase modulation device fully integrates advantages of a mechanical switch and an electronic switch, so that the function of zero passage seamless switching of voltage and current can be realized, the impacts on a low voltage power grid and the electric load of the users are avoided, and the reliability of power supply and the voltage quality are guaranteed. The low voltage load online phase modulation device ensures that the load of the three phases of the power distribution area realizes minimum unbalance degree, the switching times of the switch is minimum, and the service life of the low voltage load online phase modulation device is improved. The low voltage load online phase modulation device has the function of three-phase load adjustment, and moreover, has functions of fault protection for over-current and over-voltage and leakage protection.

An intelligent reclosure breaker comprises an operating mechanism, a current and electric leakage detection module, a power module, a voltage detection module, an electric reclosure mechanism, a control unit and a signal interaction module, wherein the voltage detection module is connected to the incoming line side of a main circuit and the rear end of a contact device; the signal interaction module is connected with the control unit and used for signal data interaction. According to an automatic reclosure control method, users can set which voltage faults need tripping and which instantaneous voltage faults allow automatic reclosure through the signal interaction module; the control unit carries out automatic judgment and controls whether the operating mechanism carries out tripping or not according to current signals and voltage signals input by the detection modules and threshold value parameters preset by the signal interaction module. After instantaneous voltage or current faults cause tripping, the control unit carries out automatic judgment to determine whether the faults are allowed to be recovered or not according to the voltage signals collected by the voltage detection module after the breaker trips and the threshold value parameters preset by the signal interaction module, and controls the electric reclosure mechanism whether to carry out electric reclosure or not.

The invention discloses a non-stick overvoltage and under-voltage protector with a leakage protection function. The non-stick overvoltage and under-voltage protector comprises a box body and a control unit, wherein the control unit comprises a power circuit (1), a current sampling circuit (2), a voltage sampling circuit (3), a microprocessor (4), a key processing circuit (5), a working state indicating circuit (6), a magnetic relay driving circuit (7), a magnetic latching relay (8), a leakage mutual inductor (9), an energy-storage capacitor (10) and a chip peripheral circuit (11). According to the non-stick overvoltage and under-voltage protector with the leakage protection function provided by the invention, a power supply is switched on automatically when the power voltage restores to a normal voltage range after an under-voltage protection action is taken, so that the continuity of power supply is ensured, and the power supply quality is ensured; and after a leakage protection action is taken, the power supply is switched on automatically after a fault is cleared and a manual key is pressed for confirming, the power supply continuity is ensured, and personal safety is protected.

The invention provides a parallel online automatic commutation device of a low-voltage load. The commutation device comprises a control circuit, an input module, a commutation switch module and an output module; and the control circuit receives a commutation phase sequence state instruction sent by a distribution and transformation terminal, calculates an operation instruction of the commutation switch module, and realizes online commutation of the low-voltage load. The invention also provides an operation method of the device. The operation method comprises that 1) the three-phase voltage of power grid, a current of the low-voltage load and a phase sequence state when the low-voltage load is connected to the power grid are collected; 2) the commutation phase sequence state instruction is calculated; and 3) the operation instruction of the device is calculated, and online commutation of the low-voltage load is realized. Compared with the prior art, the device and operation method thereof use an intelligent optimized algorithm to optimize and select the phase sequence state combination of the low-voltage load in a power distribution district, and change the low-voltage load randomly among phases A, B and C, and three-phase loads in the power distribution district are balanced.

The embodiment of the present invention discloses a power supply control circuit and method of a mobile terminal and a power supply management module. The power supply control circuit comprises an external power supply input end, a battery, a voltage conversion module, a first switch, a mainboard, the power supply management module, a voltage comparison module, a switch control module and a voltage stabilization capacitor. The voltage comparison module and the power supply management module are connected with the switch control module, and the switch control module is connected with the first switch. The switch control module is used to control the first switch to connect an external power supply circuit if the voltage comparison module determines that an external power supply inputted by the external power supply input end satisfies a threshold condition, and the power supply management module outputs an instruction for connecting the external power supply circuit, so that the battery does not supply power, the situation that the battery is charged while discharging can be reduced, the charge and discharge times of the battery can be reduced, and the service life of the battery is prolonged. Otherwise, the switch control module is used to control the first switch to connect a battery power supply circuit, thereby guaranteeing the power supply continuity to the mobile terminal.

The present invention discloses a distribution automation cabinet including a cabinet body and a plurality of drawer type cabinets. The cabinet body movably connects with the drawer type cabinets, and the drawer type cabinets are arranged in the cabinet body. The distribution automation cabinet is provided with a plurality of functional modules, and the functional modules are assembled in the distribution automation cabinet in a drawer manner for forming drawer unit modules. Compared with the prior art, the distribution automation cabinet provided by the present invention can be used as a standardized product for production, and various functional module equipment in the distribution automation cabinet can also be used as standardized products for production so as to match with any one ring network cabinet group provided by the prior art or available in the market. And the distribution automation cabinet significantly solves a security problem of outdoor opening and closing existed in the prior art, simultaneously, enhances supply electricity continuity of an outdoor opening and closing place, facilitates the development and management of smart power grids of our country, and therefore, the distribution automation cabinet has a wide application prospect.

The invention provides an electrified railway external power grid power supply structure. An external power grid comprises transformer substations and power transmission lines; the A-type transformer substation supplies power to the B-type transformer substation, the C-type transformer substation and the traction transformer substations through the corresponding power transmission lines, the B-type transformer substation supplies power to the C-type transformer substation and the traction transformer substations through the corresponding power transmission lines, and the C-type transformer substation supplies power to the traction transformer substations through the corresponding power transmission lines; it is defined that the traction transformer substations serve as leaves, the A-type transformer substation serves as a root, the B-type transformer substation and the C-type transformer substation between the A-type transformer substation and the traction transformer substations serve as nodes; through the power transmission lines, the A-type transformer substation, the B-type transformer substation, the C-type transformer substation and the traction transformer substations are connected into a tree-shaped-structure power supply network from the high-voltage level to the low-voltage level; as long as every two adjacent traction transformer substations (leaves) upwards retrospect and can find the same node or root, the intervening subarea substations can communicate, cut-through power supply is implemented, and an equalizing current cannot be generated; and every two corresponding power transmission lines are arranged into one set, capacity standby application is conducted, and traction power supply is not affected under overhauling or breaking down of bus bars of any power transmission line and transformer substation subsection.

The invention provides a novel commutation switch device. The device comprises a monitoring unit, a commutation switch unit and a compensation unit, wherein the monitoring control comprises a controlmodule, an analog quantity measurement module, a communication switch trigger and feedback module, a compensation trigger and feedback module and a communication module, the control module is used forreceiving a commutation command transmitted from the communication module and receiving a voltage / current signal acquired by the analog quantity measurement module, and information returned from morethan two modules is received by sending out a control command on the commutation switch unit and the compensation unit according to a certain control strategy. By the commutation switch device, the commutation time of a conventional commutation switch-type three-phase load unbalanced management device during the commutation process can be prevented, zero switching time can be achieved, and the power supply continuity is ensured.

The invention provides a railway traction power-obtaining power supply for a through line. The power supply comprises a high-voltage switch cabinet, a transformer and a medium-voltage loop which are arranged on a current path in sequence, wherein a power conversion unit is connected with the medium-voltage loop through the coupling transformer; and a monitoring and control unit is connected with the high-voltage switch cabinet, the transformer, the medium-voltage loop and the power conversion unit through a signal cable. The power supply is an apparatus for obtaining power from a contact network and supplying the purified high-quality three-phase 10kV power supply to the through line; namely, the input power supply is obtained from the 27.5kV (or 55kV) alternating current from the electrified railway traction contact network; then the alternating current is subjected to voltage reduction by the transformer, and then is dynamically adjusted and filtered by a voltage source connected with a 10kV loop in series so as to obtain the stable power supply for the through line; and in addition, the three-phase unbalance, voltage fluctuations, and voltage harmonics caused by railway train operations can be eliminated, so that the voltage quality on the output side can be ensured.

The invention discloses a power distribution automation cabinet. The power distribution automation cabinet is composed of a cabinet body and a plurality of unit modules. Each unit module is movably connected with the cabinet body in a pulling-out manner and can be internally arranged in the cabinet body. Each unit module is provided with a plurality of secondary elements with different functions. The power distribution automation cabinet comprises a first power distribution cabinet and a second power distribution cabinet. The first power distribution cabinet is composed of a plurality of single-loop control protection unit modules. The second power distribution cabinet comprises a wiring terminal module, a DTU protection integration unit module, an ONU communication integration unit module and a power supply unit module. The first power distribution cabinet and the power distribution cabinet are electrically connected through the wiring terminal module. Compared with the prior art, the power distribution automation cabinet can be produced as a standard product, all function module equipment of the power distribution automation cabinet can also be produced and designed as standard products, and the power distribution automation cabinet can be matched with any kind of ring network cabinet group for usage; in addition, the safety problems of an outdoor switching station are solved, and the power supply continuity of the outdoor switching station is simultaneously improved.

The invention discloses a distribution automation cabinet. The distribution automation cabinet comprises a cabinet body and a plurality of drawer type cabinets, the cabinet body is movably connected with the drawer type cabinets, the drawer type cabinets are positioned in the cabinet body, the distribution automation cabinet is provided with a plurality of function modules, and the function modules are assembled in the distribution automation cabinet in a drawer manner to form drawer unit modules. Compared with the prior art, according to the distribution automation cabinet, the distribution automation cabinet can be produced as standardized products, and the function module devices in the distribution automation cabinet can be produced and designed as standardized products so that the distribution automation cabinet can be employed with the cooperation of any ring main unit provided in the prior art or sold in the market; the problem of the security of the outdoor switching station in the prior art is substantially solved; besides, the power supply continuity of the outdoor switching station can be improved, the development and management of the national smart grid can be facilitated, and the application prospect is very wide.

The application discloses a photovoltaic building integrated system comprising a control unit, a photovoltaic power generation unit, an energy storage unit, a photovoltaic inverter unit, and an energystorage inverter unit. The photovoltaic power generation unit, the energy storage unit, the photovoltaic inverter unit, and the energy storage inverter unit are connected with the control unit. The photovoltaic power generation unit is used for converting the solar energy into the electric energy, providing power for a load by the photovoltaic inverter unit, and / or storing the power into the energy storage unit. The energy storage unit includes one or more groups of energy storage battery modules; and each group of energy storage battery modules is used for storing the power generated by thephotovoltaic inverter unit and providing power for the load by the energy storage inverter unit. The control unit is used for selecting one from multiple power supplies for powering the load accordingto states of the photovoltaic power generation unit and the groups of energy storage battery modules and controlling the photovoltaic power generation unit to charge a storage battery module. The multiple power supplies include photovoltaic power generation parts and each group of energy storage battery modules. According to the application, the residual power generated by the photovoltaic powergeneration unit can be stored into the energy storage battery modules, thereby ensuring the continuity of power supply of the BIPV system.

The invention discloses a distribution automation cabinet, which comprises a cabinet body and a plurality of unit modules, wherein each unit module is movably connected to the cabinet body in a drawing-out mode and can be arranged in the cabinet body, and each unit module is provided with a plurality of secondary elements with different functions; the distribution automation cabinet comprises a first power distribution cabinet and a second power distribution cabinet, the first power distribution cabinet is formed by a plurality of single-loop control protection unit modules, and the second power distribution cabinet comprises a wiring terminal module, a DTU protection comprehensive unit module, an ONU communication comprehensive unit module and a power supply unit module, wherein the firstpower distribution cabinet and the second power distribution cabinet are electrically connected through the wiring terminal module. Compared with the prior art, the distribution automation cabinet provided by the invention can be used as a standard product for production, each functional module device of the distribution automation cabinet can also be used as a standardized product for productiondesign, and the distribution automation cabinet can be matched with any ring network cabinet group for use; the safety problem existing in outdoor opening and closing is solved, and the power supplycontinuity of outdoor opening and closing is improved.

The invention discloses a GIS-based distribution network emergency repair video command quick positioning system, which comprises an application server, a website server, a data server, a management working station, a magnetic disk array, a master station switch and a firewall. The GIS-based distribution network emergency repair video command system is in data exchange with a distribution network automatic master station system, a PMS system, a marketing management system, a 95598 system, a power utilization information acquisition system and a GIS system of a power system via the firewall, the master station switch and an information exchange bus, and a fault region is quickly positioned according to video data transmitted by a vehicle-mounted field monitoring device or a fixed tower monitoring device. The GIS-based distribution network emergency repair video command quick positioning system of the invention comprises the vehicle-mounted field monitoring device and the fixed tower monitoring device, power fault problems are acquired in multiple channels, the power fault can be quickly positioned by the distribution network emergency repair video positioning transmission system, and timeliness of emergency repair is ensured.

The invention provides an on-line three-phase load unbalance processing method suitable for a low-voltage distribution network. The on-line three-phase load unbalance processing method comprises the following steps of: monitoring three-phase load by three-phase load monitoring units on the low voltage side of a distribution transformer, and transmitting monitoring data to three-phase load unbalance monitoring units of the distribution transformer; judging whether the three-phase load unbalance exceeds a standard value or not by the three-phase load unbalance monitoring units of the distribution transformer; if the three-phase load unbalance exceeds the standard value, transmitting signals to an on-line load phase modulation control unit by a communication unit; judging whether the three-phase load unbalance of the distribution transformer is caused by the three-phase load unbalance of a main low-voltage circuit or not by the on-line load phase modulation control unit; and if so, setting an on-line load phase modulation strategy according to the monitoring data of the load monitoring units of branches of three phases of the main low-voltage circuit, sending a control command to an on-line load phase modulation switch combination unit by an on-line load phase modulation judging and controlling unit, and switching the load phases of the branches of users so as to realize the on-line three-phase load unbalance processing.

Disclosed is a multifunctional isolating switch comprising a mechanical switch structure component, a loop current detecting unit (10), an auxiliary power generating unit (20), a processor unit (30) and a display module (40). The loop current detecting unit (10) is used for detecting the current of a main power supply loop; the auxiliary power generating unit (20) is used for supplying auxiliary power for a switch body; the power of the processor unit (30) is supplied through the auxiliary power generated by the auxiliary power generating unit (20), and the processor unit (30) receives the detected current of the loop current detecting unit (10), measures and analyzes the detected current, provides the current measurement analysis result and provides display information according to the current measurement analysis result; the display module (40) receives display information from the processor unit (30) and displays the corresponded current value according to the received display information.

A modularized low-voltage distribution line power supply device comprises at least one insulating base module with a concave cavity, the insulating base module is provided with at least one wire inlet end, at least one wire outlet end and connecting conductors, the number of the connecting conductors is equal to the number of the wire inlet ends and the number of the wire outlet ends, and the connecting conductors are connected with the wire inlet ends and the wire outlet ends. The device further comprises a monitoring box module arranged corresponding to the concave cavity, an electronic controller is arranged in the monitoring box module, a contact conductor is arranged on the monitoring box module, the monitoring box module and the concave cavity are correspondingly arranged in a pluggable mode, and the contact conductor is in conductive contact with the connecting conductor. The electronic controller of the power supply device can be independently replaced in a live-line mode, an insulating base module connected with a primary conductive loop does not need to be detached, power supply continuity is guaranteed, equipment maintenance cost and labor cost are reduced, reliability of a monitoring function and a communication function is improved, and secondary upgrading and reconstruction are easy.

The invention discloses a residual current operated circuit breaker with a self-checking function. The residual current operated circuit breaker comprises a housing which is internally provided with aPCB control circuit assembly board, a residual current protection release, a zero sequence current transformer, an alarm indicating lamp, and a buzzer, wherein a main control chip and a silicon controlled rectifier connected with the main control chip are arranged on the PCB control circuit assembly board, the silicon controlled rectifier is simultaneously connected with the residual current protection release, and the zero sequence current transformer, the alarm indicating lamp and the buzzer are respectively connected with the main control chip. The residual current operated circuit breakeris advantaged in that, compared with the prior art, the residual current circuit breaker with the self-checking function can automatically perform periodic self-checking on whether faults exist or not without manual intervention, so power utilization safety of a user is further ensured, an electric connection state of the main circuit cannot be disconnected in the self-checking process, and powersupply continuity of related equipment can be ensured.

A self-resetting overvoltage and undervoltage protector with leakage protection function, which includes a box body and a control unit, and the control unit includes a power supply circuit (1), a current sampling circuit (2), a voltage sampling circuit (3), and a microprocessor ( 4), button processing circuit (5), working state indication circuit (6), magnetic relay drive circuit (7), magnetic latching relay (8), leakage transformer (9), energy storage capacitor (10) and chip peripheral circuit (11), a self-resetting overvoltage and undervoltage protector with leakage protection function provided by the present invention, after the overvoltage and undervoltage protection action, when the power supply voltage returns to the normal voltage range, the power supply is automatically turned on to ensure the continuity of power supply It ensures the quality of power supply; after the leakage protection action, after troubleshooting the fault and confirming with the manual button, it will automatically turn on the power supply, ensuring the continuity of power supply and protecting personal safety.

The invention discloses a laboratory isolation power supply insulation fault positioning system. The system comprises an isolation transformer and an experiment table. The isolation transformer is successively connected in series with an insulation monitor and an external connection alarm. The external connection alarm is also connected to an alarm display instrument. The experiment table is connected to an experiment control chamber. An experiment control bench is connected to the insulation monitor. The isolation transformer is also successively connected in series with an insulation fault tester and an insulation fault positioning instrument through a current transformer. The experiment table comprises several load circuits connected in parallel with the insulation fault tester. The load circuits are provided with switches and positioning mutual inductors. The positioning mutual inductors of the load circuits are connected to the insulation fault positioning instrument. In the invention, when a fault is discovered, an alarm is emitted rapidly and positioning is performed so that a safe experiment platform is provided for an experimenter; personal safety and equipment safety areprotected; and the system has a certain improvement effect on teaching.

The present invention discloses a power distribution automation cabinet which comprises a cabinet body and a plurality of drawer type cabinets. The cabinet body is movably connected to the plurality of drawer type cabinets, and the drawer type cabinets are in the cabinet body. In addition, the power distribution automation cabinet also provided with a heat radiation component and a heat recovery system. The heat radiation component is arranged at the outer wall of the power distribution automation cabinet and does not communicate with the internal part of each cabinet. The heat recovery system comprises a rectangular box which is provided with an intake port, an air outlet, a heat exchanger and a storage battery. Compared with the prior art, the power distribution automation cabinet provided by the invention can individually supply the lighting system in the power distribution automation cabinet, the power distribution automation cabinet can be produced as a standard product, each function module equipment in the power distribution automation cabinet can be produced and designed as a standard product, thus the power distribution automation cabinet can be used with any ring main unit provided by the prior art or sold in the market, and thus the application prospect is very board.

The invention discloses a safe power utilization device, and the device comprises an isolation transformer composed of a commercial power side coil, a safe power side coil and a triangular winding; a first switch is arranged on a loop where the commercial power side coil is located, a second switch is arranged on a loop where the safe power side coil is located, and a third switch is arranged on a commercial power output circuit. A triangular winding is used for eliminating 3k-order harmonics so as to realize live switching. When the controller detects that the current value of at least one phase in the three-phase alternating current is larger than a first threshold value and the current value of each phase is smaller than a second threshold value (the second threshold value is larger than the first threshold value determined by the rated load of the isolation transformer and larger than the rated load), the state of power supply by the first switch and the second switch is switched into the overload emergency power supply state of direct power supply by the third switch, so the safe power utilization device can keep power supply under the condition of bearing a load exceeding a rated value of the safe power utilization device, devices of the safe power utilization device cannot be damaged, the power supply continuity is ensured, and the user experience is improved.

The invention discloses a distribution automation cabinet. The distribution automation cabinet comprises a cabinet body and a plurality of drawer cabinets, wherein the cabinet body is movably connected to the drawer cabinets, and the drawer cabinets are located in the cabinet body. The distribution automation cabinet is provided with a plurality of functional modules, and each functional module isassembled in a drawer type in the distribution automation cabinet to form a drawer unit module. Compared with the prior art, the distribution automation cabinet can be produced as a standardized product and functional module devices in the distribution automation cabinet can also be designed and produced as standardized products so as to be used together with any ring network cabinet group provided by the prior art or sold on the market; besides, the distribution automation cabinet can significantly solve the safety problems existing in the outdoor opening and closing in the prior art, and atthe same time, it can improve the continuity of power supply in outdoor opening and closing and is more conducive to the development and management of China's smart power grids, thus the distributionautomation cabinet has very broad application prospect.

The invention discloses an uninterrupted switching device and method for a 400Hz intermediate-frequency power supply for a ship, and the device comprises a first voltage sensor, a second voltage sensor, a third voltage sensor, a current sensor, a first full-control power electronic apparatus, a second full-control power electronic apparatus, a first switch, a second switch, and a control circuit. According to the invention, a static switching thyristor is employed, and methods of rapid voltage and current detection and power loss judgment are also employed. Moreover, the switching operation can be completed within 2.5ms, thereby guaranteeing the continuity of power supply. A proper switching strategy and a protection logic are employed, such as no switching during load short circuit, the selection of a switching point, and so on, thereby guaranteeing the safety and reliability of a switching process. A mechanical-type bypass switch is added, and the reliability of power supply is improved.

The invention belongs to the technical field of switching and mainly provides an electric dazzling-preventing circuit and system. A working voltage source in an external circuit as well as a first voltage signal and a second voltage signal which are input by a bus bar voltage source are sampled, and a corresponding control signal is output according to a first voltage sampled signal and a second voltage sampled signal for selecting the first voltage signal or a second direct current voltage signal to supply power to an alternating current contactor, so that the electric dazzling-preventing circuit can controls the state of the alternating current contactor according to the state of the external circuit, a contactor coil and a main contact maintain closed, and power supply continuity of thecircuit is maintained, and the problems that power transmission needs to be carried out manually again after the electric dazzling phenomenon in an existing electric power system is finished and thepower supply continuity of a motor or emergency lighting is influenced are solved.

An intelligent power supply switching device for providing intelligent correction function of circuit breaker closing time comprises an auxiliary power supply rapid switching device, wherein the auxiliary power supply rapid switching device monitors the split instruction signal of the incoming circuit breaker. The auxiliary power supply rapid switching device is connected with the position auxiliary contact of the incoming line breaker and the device could monitor whether the time of opening and the closing the incoming circuit breaker is within a reasonable range. If not, it will send an alarm signal. The device will automatically collect the time of opening and closing the line breaker and correct the preset value of opening and closing time of the circuit breaker through intelligent algorithm. And, the device will intelligently correct the closing time of the circuit breaker so as to improve the success rate of power switching, reduce the closing current and improve the service life of the equipment.

The invention discloses an uninterrupted switching device and method for a marine 400Hz intermediate frequency power supply, comprising a first voltage sensor, a second voltage sensor, a third voltage sensor, a current sensor, a first full-control type power electronic device, a second full-control type A power electronic device, a first switch, a second switch and a control circuit. The present invention uses a static switch thyristor, coupled with fast voltage and current detection and a power failure judgment method, the switching action can be completed within 2.5ms, ensuring the continuity of power supply; using suitable switching strategies and protection logic: if the load is short-circuited, do not switch, switch The selection of points, etc., ensures the safety and reliability of the switching process; the addition of a mechanical bypass switch increases the reliability of the power supply.

The invention discloses a low-voltage AC / DC power distribution mode conversion system and a sequential control method and device thereof, and relates to the technical field of power transmission and distribution of power systems. The system comprises a distribution power supply, a distribution line, a load, a sending end converter, a receiving end converter and a plurality of circuit breakers. According to the sequential control method of the low-voltage AC / DC power distribution mode conversion system, the states of the current and voltage in a system line are detected, the opening and closing actions of different circuit breakers are controlled, the power supply transmits power to the load through the sending end converter and the receiving end converter, and switching from an alternating current power supply mode to a direct current power supply mode is completed. The switching rapidity and reliability are ensured by determining the switching control scheme of the switches at the two sides by detecting the voltage and current change conditions at the two sides, the alternating-current power distribution mode is smoothly switched to the direct-current power supply mode when the terminal demand power is increased and the voltage drop is obvious, a communication line does not need to be additionally arranged, the cost is low, and the safety of components, such as the converter, etc., and the user power supply continuity can be ensured.