41results about How to "Prevent reclosing" patented technology

A metal silicide fuse for a semiconductor device. The fuse includes a conductive region positioned adjacent a common well of a first conductivity type, a terminal region positioned adjacent a well of a second conductivity type, and a narrowed region located between the terminal region and the conductive region and positioned adjacent a boundary between the two wells. Upon applying at least a programming current to the fuse, the fuse “blows” at the narrowed region. The diode or diodes between wells of different conductivity types wells and the Schottky diode or diodes between the remaining portions of the fuse and wells adjacent thereto control the flow of current through the remainder of the fuse and through the associated wells of the semiconductor device. When the fuse has been “blown,” the diodes and Schottky diodes prevent current of a normal operating voltage from flowing through the wells of the semiconductor device.

A metal silicide fuse for a semiconductor device. The fuse includes a conductive region positioned adjacent a common well of a first conductivity type, a terminal region positioned adjacent a well of a second conductivity type, and a narrowed region located between the terminal region and the conductive region and positioned adjacent a boundary between the two wells. Upon applying at least a programming current to the fuse, the fuse “blows” at the narrowed region. The diode or diodes between wells of different conductivity types wells and the Schottky diode or diodes between the remaining portions of the fuse and wells adjacent thereto control the flow of current through the remainder of the fuse and through the associated wells of the semiconductor device. When the fuse has been “blown,” the diodes and Schottky diodes prevent current of a normal operating voltage from flowing through the wells of the semiconductor device.

The invention relates to a hydraulic fracturing and methane in-situ blasting cooperative fracturing permeability-increasing method which is suitable for shale gas reservoir exploitation. The method comprises the steps that horizontal drilling construction is conducted on a to-be-constructed area, and then cracks are formed around the hole wall of a horizontal drill hole through energy-gathered perforation; the cracks around the horizontal drill hole continue to be expanded in a hydraulic fracturing mode, and methane extraction is conducted after fracturing fluid is discharged; after methane gas is reduced, in-situ blasting fracturing is conducted on methane participating in the horizontal drill hole; after blasting, the cracks in the horizontal drill hole continue to be expanded, so that the methane continues to seep, and then extraction continues to be conducted; and blasting fracturing and extraction operation are repeated, so that blasting cooperative fracturing permeability increasing is achieved, and the shale gas exploitation effect is greatly enhanced. The method is reasonable in design, high in construction operation feasibility and suitable for fracturing transformation of unconventional oil and gas reservoirs such as shale gas reservoirs, coal bed gas reservoirs and tight sandstone gas reservoirs.

The invention provides a special fault indicator for a high-voltage power transmission network cable line. The special fault indicator comprises a measurement module, a power taking module, a power supply module, an energy storage module, an MCU (microprogrammed control unit) and a communication module, wherein the measurement module is connected with an ADC (analog-to-digital converter) unit in the MCU and is used for transmitting acquired current data of the cable line to a central processing unit in the MCU through the ADC unit and performing cable fault judgment through the central processing unit; the communication module is used for uploading the current data of the monitored cable line and fault signals obtained through judgment to an upper system; the power taking module is used for acquiring electric energy from the cable line through induction, is connected with the energy storage module and charges the energy storage module; the power taking module is connected with the power supply module and supplies power to the MCU; when the cable line has a fault, the energy storage module replaces the power taking module to supply stored power to the MCU. According to the special fault indicator for the high-voltage power transmission network cable line, effective electrical quantity detection can be performed on grounding faults and short-circuit faults of the high-voltage cable, and fast online fault positioning of a fault section is realized.

A resonant laser powered micro accelerator platform capable of producing relativistic or near relativistic electrons and, optionally, x-rays. The apparatus has a pair of parallel slab-symmetric dielectric slabs that are separated by a narrow vacuum gap that is preferably tapered. The slabs have a top surface with reflective layers with many periodic slots creating longitudinal periodicity in the structure fields when laser light is directed on the reflectors in one embodiment. Electrons introduced into the gap are accelerated along the length of the slabs. The reflective surface of the slabs is preferably a laminate of alternating layers of high index and low index of refraction materials.

The invention discloses a thyristor rectification tractive power supply system and a protective method. When a short-circuit fault occurs, the thyristor of a traction substation thyristor rectifier closest to a fault element is stopped from working; if the sum value of the fault mark values, measured and calculated after the thyristor is stopped from working, of the element is larger than or equal to 1, a permanent fault is determined, the thyristors of other traction substation thyristor rectifiers of a whole line are stopped from working, all related direct-current isolation switches are opened, the thyristors of the traction substation thyristor rectifiers of the whole line return to work, the power supply of the system is restored, and if the sum value is not larger than or equal to 1, a temporary fault is determined, the related thyristors return to work, and the normal power supply of the system is restored. According to the thyristor rectification tractive power supply system and the protective method, a direct-current breaker can be eliminated, investment is reduced, implementation is convenient, and the system is suitable for carrying out new line construction or old line improvement on fields with lines which are not too long (within 20km and less than 10 traction substations). When the lines are too long, a small number of direct-current breakers can be used for dividing the tractive power supply system.

The invention discloses a petroleum propping agent with ultra-low density and high strength. The petroleum propping agent is prepared by uniformly mixing 30 to 50 weight percent of white mud, 30 to 50 weight percent of kaolin and 10 to 20 weight percent of feldspar serving as raw materials, adding a reinforcing agent such as aluminum sol, silicon sol or aluminum phosphate sol and the like in an amount which is 2 to 5 percent of the total weight of the three raw materials and performing wet ball milling, superfine grinding, spray drying, rolling forming, drying, screening and high-temperature sintering. The petroleum propping agent with ultra-low density and high strength has the characteristics of ultra-low apparent density, high strength and low crushing rate, so the propping agent has good flow conductivity, can quickly fill fractures in hydraulic fracturing, effectively props the fractures all the time after the hydraulic fracturing is finished, prevents reclosing of the fractures,enables the stratum fluid to enter the fractures in a linear mode, improves the hydraulic fracturing effect, and is favorable for petroleum yield increment. Meanwhile, the local resources can be fully utilized as raw materials for preparation so as to reduce the manufacturing cost of the propping agent.

The invention relates to a supercritical carbon dioxide sand-carrying coal seam fracturing device and method. The supercritical carbon dioxide sand-carrying coal seam fracturing device comprises a liquid CO2 storage tank, a booster pump, a heating device, a high-pressure ejector and a hole packer, wherein the liquid CO2 storage tank is connected with the high-pressure ejector through the booster pump and the heating device; and the high-pressure ejector is connected with the hole packer and further provided with an ejection medium inlet. According to the invention, supercritical CO2 is used asa fracturing fluid, and the extremely strong diffusivity and solubility of the supercritical CO2 are utilized, so that micro-fractures in a coal seam can be communicated with each other, and the airpermeability of the coal seam is improved. Ceramsite is carried to serve as a propping agent, the fractures formed after fracturing can be kept open, the ceramsite has good flow conductivity, and gascan smoothly pass through the ceramsite in the gas extraction process.

The invention discloses an underground coal mine hydraulic sand fracturing system and method. The underground coal mine hydraulic sand fracturing system comprises a water supply system, a fluid distribution system, a sand mixing system, a fracturing system and a high-pressure manifold system; the fracturing system is formed by two fracturing pump groups in parallel; the high-pressure manifold system comprises a Y-shaped tee, and two inlet channels of the Y-shaped tee separately communicate with outlets of the two fracturing pump groups; and the fluid distribution system comprises two fluid distribution pools. The fracturing method is implemented based on the fracturing system and comprises the steps that fracturing liquid is prepared by densifiers, crosslinking agents, anti-swelling agents, gel breakers and water according to proportion; the particle size of a supporting agent is 40-70 meshes, and the volume density of ceramsite sand is 1.25g / cm<3>; and fracturing is carried out according to the sequence of first hydraulic fracturing seam generating and later fracturing liquid sand-carrying fracturing support. The underground coal mine hydraulic sand fracturing system has the beneficial effects that the fracturing system is simple in structure and reasonable in layout, and is suitable for sand-carrying fracturing use of underground narrow and small or long and narrow space; andthe fracturing liquid prepared by the fracturing method has suspended sand characteristic, can be suitable for upward drilling sand-carrying fracturing, and has the environmental protection characteristic of being capable of directly discharged.

A method is for manufacturing a cartridge (10, 27, 30) for containing and meterably dispensing a reservoir (11) contained flowable dental material (36). The reservoir (11) is connected to a cannula section (14) for dispensing the dental material (36). A separate functional element (15) is connected to the cannula section (14). The cartridge (10, 27, 30) is manufactured together with the functional element (15) according to a multicomponent injection molding method. The functional element (15) is designed as a detachable closing element. The functional element (15) and the cartridge (10, 27, 30) are positioned during the manufacture such that the functional element (15) is mounted at least partially in the cannula section (14). The functional element (15) has a plug part (16) for closing the cannula section (14) and a cannula duct (24) of the cannula section (14) is filled at least partially with the plug part (16).

A method and apparatus for fault identification in a transmission line are provided. The method may include measuring at an end of the transmission line when the transmission line has a fault to obtain a measured signal, comparing the measured signal with a predefined standard signal, the predefined standard signal having beat frequency characteristic; and identifying that the fault is a transient fault if the measured signal matches the predefined standard signal according to a result of the comparison, or the fault is a permanent fault if the measured signal does not match the predefined standard signal according to the result of the comparison.

The invention discloses an oral cavity drag hook system and a using method thereof. The oral cavity drag hook system comprises an oral cavity drag hook device, a soft palate drag hook device and a pharyngeal back wall soft tissue opening device, wherein the oral cavity drag hook device comprises a tongue pressing component, a first adjusting part and an upper tooth opening component; the tongue pressing component and the upper tooth opening component are both connected with the first adjusting part, and the first adjusting part adjusts the tongue pressing component and the upper tooth openingcomponent to expand the lower jaw and the upper jaw; the pharyngeal back wall soft tissue opening device is positioned above the oral cavity drag hook device and comprises two soft tissue opening components and a second adjusting part connected with the two soft tissue opening components, wherein the second adjusting part adjusts the two soft tissue opening components to distract the pharyngeal back wall soft tissue; the soft palate drag hook device is positioned between the two soft tissue opening components, and the oral cavity drag hook system is easier to dilate the oral cavity, so that the back wall of the oral cavity pharynx is shown in front of an operator as much as possible, thereby maintaining a good and stable operation visual field, and meeting the requirements of the operator.

The embodiment of the invention belongs to the field of new energy vehicles and discloses an abnormality protection device for the operation of an electric vehicle. The device comprises an inner sidevoltage detection module, an outer side voltage detection module, a judgment module and a control module; the inner side voltage detection module is used for detecting the voltage of the first end ofa main positive relay in the high-voltage loop of the electric vehicle and inputting the voltage of the first end of the main positive relay to the judgment module; the outer side voltage detection module is used for detecting and obtaining the voltage of the second end of the main positive relay and inputting the voltage of the second end of the main positive relay to the judgment module; the judgment module is used for outputting a switching-off indication signal to the control module after identifying that the abnormal switching off of the main positive relay according to the voltage of thefirst end of the main positive relay and the voltage of the second end of the main positive relay; and the control module is used for switching off the coil drive of the main positive relay accordingto the switching-off indication signal. Therefore, the situation that the relay is switched on again after being abnormally switched off is avoided, the safe operation of the whole vehicle is guaranteed, and the failure rate of the vehicle is reduced.

The invention discloses an embroidery machine with LED lamp illumination. The embroidery machine comprises a bearing table. Two sides of the top of the bearing table are both fixedly connected to a supporting table. The tops of two supporting tables are fixedly connected through a fixing table. The front side of the fixing table is fixedly connected to a transmission rod through a fixing block. Three embroidery bodies are movably connected to the transmission rod. The top of the bearing table is fixedly connected to a transmission rack. The top of the bearing table is also fixedly connected to a motor box. The top of the transmission rack is movably connected to an embroidery table. The top of the embroidery table is provided with an embroidery groove. Two sides of the top of the embroidery table are both fixedly connected to an illuminating apparatus. The provided illuminating apparatuses realize the illumination effect. When the embroidery machine is operated at night, the LED lamps can be used to illuminate embroidery products, needles and threads in the embroidery groove, the light will not be blocked by the embroidery machine, the product quality is guaranteed, and the embroidery machine is more convenient to use.

The invention discloses a muddy silt natural gas hydrate multi-branch hole well drilling and completion integrating method, wherein loosening is carried out through one string. Multi-branch holes areformed through the set of string of well drilling and completion, in the drilling process of the different branch holes, a drilling tool assembly does not need to be pulled out from a main well completely, coiled tubing is adopted for hydraulic jet drilling, and after drilling is conducted to the preset depth, gravel is reversely filled directly without pulling out drilling tools. The technological means of combining multi-branch hole gravel filling well completion with large-size main well casing well completion is adopted, the risk of reclosing of the multi-branch holes is prevented, the purposes of stabilizing the main well and preventing a formation from losing stability are achieved, the effect of production increasing through multi-branch hole limited sand control mining can be achieved, well drilling and completion support is provided for a submarine natural gas hydrate multi-branch hole limited sand control mining method, and high practical value and economic value are achieved.

A method is for manufacturing a cartridge (10, 27, 30) for containing and meterably dispensing a reservoir (11) contained flowable dental material (36). The reservoir (11) is connected to a cannula section (14) for dispensing the dental material (36). A separate functional element (15) is connected to the cannula section (14). The cartridge (10, 27, 30) is manufactured together with the functional element (15) according to a multicomponent injection molding method. The functional element (15) is designed as a detachable closing element. The functional element (15) and the cartridge (10, 27, 30) are positioned during the manufacture such that the functional element (15) is mounted at least partially in the cannula section (14). The functional element (15) has a plug part (16) for closing the cannula section (14) and a cannula duct (24) of the cannula section (14) is filled at least partially with the plug part (16).

The invention discloses a controllable lockable protection switch, a switch control system and a lithium battery. The controllable lockable protection switch comprises a first contact, a second contact, double metal pieces, a heating unit or a solenoid coil, and a locking mechanism. The double metal pieces are connected with the first contact, the first contact and the second contact are arranged oppositely, the heating unit or the solenoid coil is arranged close to the double metal pieces, the double metal pieces are controlled through the heating unit or the solenoid coil to drive the first contact and the second contact to be connected or disconnected, and the locking mechanism is used for preventing the first contact and the second contact from being closed after the first contact and the second contact are disconnected. The heating unit or the solenoid coil is arranged to control the double metal pieces so that closing and breaking of the switch can be controlled, the locking mechanism is arranged, so that after the switch is broken, the switch is prevented from being closed again, the protection effect on a whole circuit is achieved, and after the protection switch of the battery loses efficacy, explosion caused by the fact that the battery is charged all the time is avoided.

The invention relates to a circuit breaker having two parallel current paths each with a contact point (15, 18; 15, 22) which, as the main and secondary current paths (19, 21), are connected, via a contact device (15, 17, 18, 22), in series with a coil (11) of a magnetic trip (10), the armature (12) of which, in the event of a fault, opens the contact point (15, 18) of the main current path (19) which is formed exclusively only by the series circuit of the contact device (15, 17, 18) with the coil (11). In order to provide a further circuit breaker which, in the case of energy losses which are minimized during normal continuous operation, prevents the formation of an arc when the circuit is interrupted in the event of a fault and therefore also largely prevents contacts from burning away, provision is made, in the case of a circuit breaker according to the invention, for an interrupter and trip insert (24) to be arranged in the secondary current path (21), which insert, in the event of a short circuit, interrupts the secondary current path and trips a switching lock (30) to open and secure the contact device (15, 17, 18, 22).

A fault detection system that includes a recloser configured to perform a reclosing operation in response to detecting overcurrent, where the recloser includes a communications device for receiving communications signals. The system also includes a transformer having an outer can, a sensor mounted to the can and extending into the can for measuring pressure therein, where the sensor includes a mechanical indicator that extends when overpressure is detected. The transformer further includes a radio mounted to the can and coupled to the sensor, where the radio includes a switch coupled to the mechanical indicator and a transmitter. When the mechanical indicator extends in response to detecting overpressure in the can it causes the switch to close which causes the transmitter to send a signal that is received by the communications device, which prevents the recloser from reclosing.

The present invention provides a method for current for fault identification in a transmission line and an apparatus thereof. The method comprises the following steps: measuring the real-time values of the currents and the voltages of the other unbroken healthy phase conductors when a single-phase fault occurs; calculating the inductive voltage and the capacitive coupling voltage according to the measured currents and voltages respectively; comparing the capacitive coupling voltage with the inductive voltage multiplied by a factor, in which the multiplication result is used as a self-adjusted threshold based on the real time load condition of the transmission line; and identifying the fault type based on the maximum of the capacitive coupling voltage and the multiplication.

The invention discloses a petroleum propping agent with ultra-low density and high strength. The petroleum propping agent is prepared by uniformly mixing 30 to 50 weight percent of white mud, 30 to 50 weight percent of kaolin and 10 to 20 weight percent of feldspar serving as raw materials, adding a reinforcing agent such as aluminum sol, silicon sol or aluminum phosphate sol and the like in an amount which is 2 to 5 percent of the total weight of the three raw materials and performing wet ball milling, superfine grinding, spray drying, rolling forming, drying, screening and high-temperature sintering. The petroleum propping agent with ultra-low density and high strength has the characteristics of ultra-low apparent density, high strength and low crushing rate, so the propping agent has good flow conductivity, can quickly fill fractures in hydraulic fracturing, effectively props the fractures all the time after the hydraulic fracturing is finished, prevents reclosing of the fractures,enables the stratum fluid to enter the fractures in a linear mode, improves the hydraulic fracturing effect, and is favorable for petroleum yield increment. Meanwhile, the local resources can be fully utilized as raw materials for preparation so as to reduce the manufacturing cost of the propping agent.

The invention provides a pressure adjusting device between atria,which is integrally of a hollow structure with two open ends and comprises a support and a covering film covering the support; the support is of a retractable and expandable structure and is divided into an inflow section, a middle section and an outflow section in the axial direction of the support; when the support is in an expanded state, the diameters of the inflow section and the outflow section are larger than the diameter of the middle section, and the diameters of the ends, connected with the middle section, of the inflow section and the outflow section are smaller than the diameters of the ends, away from the middle section, of the inflow section and the outflow section; and the middle section is of a radial supporting force reinforced structure.

The invention relates to a circuit breaker having two parallel current paths each with a contact point (15, 18; 15, 22) which, as the main and secondary current paths (19, 21), are connected, via a contact device (15, 17, 18, 22), in series with a coil (11) of a magnetic trip (10), the armature (12) of which, in the event of a fault, opens the contact point (15, 18) of the main current path (19) which is formed exclusively only by the series circuit of the contact device (15, 17, 18) with the coil (11). In order to provide a further circuit breaker which, in the case of energy losses which are minimized during normal continuous operation, prevents the formation of an arc when the circuit is interrupted in the event of a fault and therefore also largely prevents contacts from burning away, provision is made, in the case of a circuit breaker according to the invention, for an interrupter and trip insert (24) to be arranged in the secondary current path (21), which insert, in the event of a short circuit, interrupts the secondary current path and trips a switching lock (30) to open and secure the contact device (15, 17, 18, 22).

The invention discloses a muddy silt natural gas hydrate multi-branch hole well drilling and completion integrating method, wherein loosening is carried out through one string. Multi-branch holes areformed through the set of string of well drilling and completion, in the drilling process of the different branch holes, a drilling tool assembly does not need to be pulled out from a main well completely, coiled tubing is adopted for hydraulic jet drilling, and after drilling is conducted to the preset depth, gravel is reversely filled directly without pulling out drilling tools. The technological means of combining multi-branch hole gravel filling well completion with large-size main well casing well completion is adopted, the risk of reclosing of the multi-branch holes is prevented, the purposes of stabilizing the main well and preventing a formation from losing stability are achieved, the effect of production increasing through multi-branch hole limited sand control mining can be achieved, well drilling and completion support is provided for a submarine natural gas hydrate multi-branch hole limited sand control mining method, and high practical value and economic value are achieved.

The invention relates to a hydraulic fracturing and in-situ methane explosion synergistic fracturing and anti-permeability method, which is suitable for the exploitation of shale gas reservoirs. Firstly carry out horizontal drilling construction in the area to be constructed, and then use concentrated energy perforation to create fractures around the wall of the horizontal drilling hole; use hydraulic fracturing to continue to expand the gaps around the horizontal drilling hole, discharge the fracturing fluid and perform methane Drainage; when the methane gas is reduced, perform in-situ detonation and fracturing on the methane participating in the horizontal borehole; after detonation, continue to expand the gap in the horizontal borehole so that the methane continues to seep out, and then continue to drain; repeated combustion Explosive fracturing and drainage operations, so as to realize the synergistic fracturing and permeability enhancement of combustion and explosion, which greatly enhances the exploitation effect of shale gas. The method is reasonable in design and highly feasible in construction operation, and is suitable for fracturing stimulation of unconventional oil and gas reservoirs such as shale gas reservoirs, coalbed gas reservoirs, and tight sandstone gas reservoirs.

The invention discloses a thyristor rectification tractive power supply system and a protective method. When a short-circuit fault occurs, the thyristor of a traction substation thyristor rectifier closest to a fault element is stopped from working; if the sum value of the fault mark values, measured and calculated after the thyristor is stopped from working, of the element is larger than or equal to 1, a permanent fault is determined, the thyristors of other traction substation thyristor rectifiers of a whole line are stopped from working, all related direct-current isolation switches are opened, the thyristors of the traction substation thyristor rectifiers of the whole line return to work, the power supply of the system is restored, and if the sum value is not larger than or equal to 1, a temporary fault is determined, the related thyristors return to work, and the normal power supply of the system is restored. According to the thyristor rectification tractive power supply system and the protective method, a direct-current breaker can be eliminated, investment is reduced, implementation is convenient, and the system is suitable for carrying out new line construction or old line improvement on fields with lines which are not too long (within 20km and less than 10 traction substations). When the lines are too long, a small number of direct-current breakers can be used for dividing the tractive power supply system.

The invention discloses a method for promoting vertical shaft shale gas exploitation through horizontal multilateral well burning explosion fracturing. The method comprises the following steps that firstly, a vertical shaft and a plurality of horizontal multilateral wells are arranged, then a first burning explosion hole packer is mounted in one of the horizontal multilateral wells, and a hole sealing section is formed between the first burning explosion hole packer and the deepest part of the horizontal multilateral well; and when blast fracturing is carried out, blast gas is injected into the hole sealing section, real-time detection is carried out through a detection device, injection of the blast gas is stopped until a value required by explosion is reached, finally an ignition head is controlled to ignite, so that the blast gas in the hole sealing section is triggered to explode, high-temperature and high-pressure gas and detonation shock waves generated by gas explosion are generated, the surrounding shale is subjected to one-time impact fracturing process through meshes in a screen pipe, the process is repeated for multiple times, and a fracture network is formed around the horizontal multilateral wells through retreating type fire blast fracturing; and therefore, a complex fracture network can be generated in the reservoir without a water source, and meanwhile, the fracture network can keep connectivity for a long time, so that extraction of shale gas is guaranteed.

The invention aims at providing an anti-drag aqueous fracturing fluid preparation, and provides a single-dosage anti-drag aqueous fracturing fluid preparation in order to overcome defects during preparation of anti-drag aqueous fracturing fluid and construction. The preparation can be compounded with water in any proportions, is good in solubility, meets the requirement on continuous mixing during on-site construction of shale gas, and has an important application value in shale gas exploration. The anti-drag aqueous fracturing fluid preparation comprises the following components by weight percentage: 4-6% of anti-drag agent, 8-12% of clay stabilizing agent, 1-3% of cleanup additive, and the balance of water, wherein the anti-drag agent is a bipolymer of acrylamide and polyethylene glycol oxide ether acrylate; the clay stabilizing agent is polydimethyl propylenediene ammonium chloride; and the cleanup additive comprises the following components by mass percentage: 9-11% of perfluorooctanoyl ethylene amino methyl diethyl ammonium iodide, 20-30% of polyoxyethylene 2,5-dimethyl stearyl alcohol ether, and 20-30% of isopropanol.

The invention provides a dual-power power supply circuit and device, the power supply circuit comprises a first phase sequence relay, a second phase sequence relay, a two-position relay, a closing loop and a front loop, coils of the first and second phase sequence relays are respectively connected with a first three-phase power supply and a second three-phase power supply to detect the phase sequence of the first and second three-phase power supplies; the front loop comprises a first normally open contact of the first phase sequence relay, a first normally open contact of the second phase sequence relay and a first coil of the two-position relay which are connected in series, and the closing loop comprises a first branch circuit and a second branch circuit which are connected in parallel, a two-position relay normally open contact which is connected in series with the first branch circuit and the second branch circuit which are connected in parallel, and a closing coil of the circuit breaker. According to the invention, the phase sequences of the first and second three-phase power supplies are detected, so that the situation that the circuit breaker is still switched on when the phase sequences are inconsistent is avoided, and the power supply safety is ensured.