52results about How to "Prevent misoperation" patented technology

The invention discloses an alloy resistor test probe card, and relates to the technical field of test probe cards. One embodiment comprises a seat body, the seat body is provided with a fine adjustment mechanism, the fine adjustment mechanism is connected with a bearing seat, the bearing seat is provided with an elastic abutting mechanism, the elastic abutting mechanism is connected with a mounting seat, the mounting seat is provided with a plurality of probe pieces, and the elastic abutting mechanism is configured to enable the probe pieces to abut against a chip. And the fine tuning mechanism is configured to drive the probe piece to move so as to adjust the position of the contact point. According to the invention, part of probes are difficult to change, and the accuracy of test points can be ensured.

The invention relates to the technical field of power distribution terminal testing, provides a power distribution terminal testing device and method, and realizes comprehensive testing of a power distribution terminal by integrating remote measurement, remote control and remote signaling testing functions. And the standardized aviation plug connection port and the universal test port are used, so that the connection is simple and convenient, and the test error risk caused by improper connection is reduced. Three-remote function detection can be completed under the condition that operation and distribution network automatic circuit breaker complete equipment is not powered off, normal power supply of a power distribution network is not affected, and power supply reliability is not reduced; the device is respectively connected to the circuit breaker and the FTU through the aviation plug wires, a tester only needs to operate on the ground and does not need to work on a tower for a long time, and the device is portable, adopts a passive design and is convenient to work; testers complete testing work on the ground, the distance between the testers and primary equipment is guaranteed, and electric shock is avoided; primary equipment maloperation is prevented, the design of the current aviation socket has a circuit releasing function, and open-circuit operation of the current transformer is completely eradicated; and the misoperation of the primary circuit breaker caused by misoperation is avoided.

The present invention discloses a short-circuit fault judgment method and device applicable to the load side of the busbar protection system. By collecting the current, busbar voltage and busbar system action signal on the load side of the busbar protection system, judging by the change of current before and after the action of the busbar protection system, judging by the protection start and protection action respectively, and assisting the judgment with the busbar protection system action signal and the re-pressure lock opening condition, the protection function of quickly judging the short-circuit fault is realized. This technical solution can accurately identify the fault after the busbar voltage maintenance system is actuated, and complete the judgment within 40ms, solving the problem of protection refusal to operate due to the reduction of short-circuit current on the load side protection after the busbar voltage maintenance system is actuated, and is suitable for various operating environments where busbar voltage maintenance systems are installed, such as industrial enterprises.

The invention discloses a transformer protection method, system and device based on aperiodic component change characteristics and a medium, and relates to the technical field of transformer protection. The method comprises the following steps: when a differential protection element of a transformer is started, calculating a second harmonic proportion and a non-periodic component change rate, and if a second harmonic braking criterion and a non-periodic component criterion are met, increasing an action threshold value; when the second harmonic braking criterion is not met, calculating the change rate of a CT transmission side aperiodic component, and judging whether the aperiodic component criterion is met or not, if yes, increasing an action threshold value, and if not, executing a differential protection action; when the non-periodic component criterion is met, it is judged that the CT is in a saturated state, sympathetic inrush current exists, the protection action threshold value is increased till the set condition is met, and the differential protection threshold returns to the original value. The working mode of differential protection can be optimized, and maloperation caused by sympathetic inrush current is avoided.

The invention discloses a residual current protection method and a residual current protection device. When the effective value of the residual current is greater than a current threshold value, the high-frequency and low-frequency energy ratio of the residual current is used as a protection criterion and compared with the protection threshold value, so that the high-frequency component of the residual current caused by human electric shock can be identified, thereby improving the sensitivity of the protection criterion to human electric shock and the reliability of the residual current protection, avoiding false operation and refusal of the protection action, and distinguishing between human electric shock faults and general leakage faults, and judging whether to cut off the line or send an alarm signal according to the fault type, thereby solving the technical problems that the existing residual current protection device determines whether the protection is to be actuated based on whether the effective value of the residual current detected in a low-voltage power supply circuit is greater than a certain set value, the residual current protection device is easily affected by the three-phase unbalanced leakage current and causes false operation and refusal to operate, and the human electric shock fault and general leakage fault cannot be distinguished, thereby reducing the reliability of the system.

The invention discloses a line protection method suitable for a power distribution network containing an unknown load branch, and the method comprises the steps: obtaining three-phase current at two ends of a protection interval, and extracting a positive-sequence component of the three-phase current to obtain a sampling sequence; according to preset windows and step length sliding grouping, calculating waveform similarity of the corresponding windows; solving an energy operator corresponding to the similarity of each window; according to an energy operator, whether a first threshold value is exceeded or not is judged firstly, and if not, no fault exists; and if so, judging whether the front-to-back ratio of the energy operator exceeds a second threshold value, if so, judging the section as a fault section, and otherwise, judging no fault. According to the method, the problem of maloperation of traditional fault protection caused by unknown load branch or distributed new energy input in the power distribution network is solved.

The invention is an adaptive CT saturation judgment method applicable to the case where the busbar CT is disconnected, which collects the busbar voltage and the current of each branch connected to the busbar; calculates the differential current and the braking current at the sampling point; and judges whether the busbar CT is disconnected. If the busbar CT is not disconnected, the saturation of the out-of-zone fault CT is identified by the sequence of the sudden changes of the small differential current and the small differential braking current sampling points, and the differential protection of the faulty busbar section is locked; if the busbar CT is disconnected, the sequence of the sudden changes of the large differential current and the large differential braking current sampling points is used to identify whether an out-of-zone fault occurs; the busbar section that needs to be locked is determined by the sampling point change rate of the small differential current of the two busbar sections connected to the busbar at the time of the fault. The present invention is applicable to busbar main connection modes with busbars, such as double busbars, double busbars with double sections, and double busbars with single sections.

The present application belongs to the technical field of power equipment monitoring and protection, and discloses a power distribution network transformer oil temperature protection threshold self-learning method and system. The method comprises: acquiring multi-dimensional state data of the power distribution network transformer in real time; inputting the data into a reinforcement learning model, and obtaining an oil temperature protection threshold adjustment amount through decision-making based on a state space, an action space and a reward function; wherein the state space is constructed based on the multi-dimensional state data, the action space corresponds to the oil temperature protection threshold adjustment amount, and the reward function is a weighted sum of safety indexes, economy indexes and stability indexes; obtaining the oil temperature protection threshold adjustment amount output by the model at the current time to update the oil temperature protection threshold; and when the real-time acquired oil temperature of the power distribution network transformer exceeds the updated oil temperature protection threshold, performing a protection action. The method provided by the present application can achieve adaptive optimization of the oil temperature protection threshold while taking into account equipment safety and operation economy, and effectively improve the accuracy and adaptability of equipment protection.

The application discloses a distance adjusting device for a punch press and relates to the technical field of punch press distance adjusting. The distance adjusting device for the punch press comprises a rack, a top column is slidably connected to the rack, the top column is used for being fixedly connected with a lower die, a jacking driving mechanism connected to the top column is further arranged on the rack, and the jacking driving mechanism is used for driving the top column to ascend and descend so as to drive the lower die to ascend and descend; and a locking mechanism is further arranged on the rack and is used for locking the position of the lower die. The application can conveniently adjust the position of the lower die.

The invention discloses a relay failure rate prediction method based on an ARMA model. The method comprises the following steps: Step 1, collecting data; the method comprises the following steps: collecting relay fault rate data and carrying out stability verification, if the relay fault rate is not stable, carrying out differential processing, and then calculating a relay fault rate autocorrelation coefficient # imgabs0 # and a partial autocorrelation coefficient # imgabs1 #; 2, a model is established, and parameters are calculated; building an ARMA (p, q) model of the relay failure rate, and calculating an autoregression order p and a moving average order q of the model; and step 3, predicting the fault rate of the relay. The operation state of the relay can be detected and evaluated, equipment damage can be prevented, the operation reliability of a secondary circuit can be improved, and operation refusal or maloperation of a relay protection device can be prevented.

An active protection method and system for internal faults in an on-load tap changer of a converter transformer includes: determining the start time of on-load tap changer operation and then extending the time interval; identifying ultra-high frequency (UHF) and high frequency (HF) pulse signals and discharge pulse times exceeding a set threshold within the extended time interval; identifying whether the on-load tap changer is adjusting a polarity-crossing or non-polarity-crossing tap position; determining the internal abnormality of the on-load tap changer based on the UHF and HF pulse signals and their pulse times during operation; and further issuing "general alarm," "serious alarm," or even "protection trip" signals based on the severity of the internal partial discharge detected by the UHF and HF signals. This invention fundamentally avoids false alarms and trips in monitoring or protection devices caused by discharge during normal tap changer operation. Furthermore, it achieves a leap from "passively preventing false operation" to "actively detecting faults," proactively preventing damage to the on-load tap changer itself or even transformer explosions caused by its faults.

The invention discloses a real-time cooperative control method and system for overcurrent protection and distributed photovoltaic of a power distribution network, which is applied to three-section overcurrent protection of a 10kV line, acquires data in real time by using hardware and a data acquisition system of an existing 10kV transformer substation, and determines whether to perform overcurrent protection or not by using voltage measured by a voltage transformer on a 10kV bus as a reference direction. Calculating the size of a phase angle between the fault current and the bus voltage, detecting whether a fault occurs or not according to the starting state of the third section of line overcurrent protection, and judging whether an external fault occurs or not in real time based on the phase angle between the fault current and the bus voltage; if an external fault occurs, the feed-in of the fault current is reduced by adjusting the output power of the distributed photovoltaic system in real time, so that the overcurrent protection maloperation of the line is prevented, and the load power loss of the line is avoided. And after the external fault is removed, the maximum power tracking control mode of the photovoltaic station is automatically recovered, and the normal operation of the photovoltaic station is recovered. On the basis of not increasing extra hardware cost, the control method provided by the invention can be realized only by adding a real-time control software module.

This invention belongs to the field of valve devices and discloses a handle valve anti-accidental contact device, comprising: a base fixed to the valve body of the handle valve; a limiting component that extends through the base and slides with the base; and a telescopic component disposed in a horizontal through hole in the base. The extensions have limiting holes that cooperate with the telescopic component to restrict the vertical movement of the limiting component relative to the base. The handle valve anti-accidental contact device of this invention achieves adjustable positioning of the limiting component through the cooperation of the telescopic component and the limiting holes. The precise cooperation between the extensions and the handle provides high limiting stability, effectively preventing accidental operation of the equipment by human error, significantly reducing human error, and ensuring the safe and stable operation of the unit.

The utility model relates to an optical lens structure for multiple light sources, which comprises a cover plate, three groups of optical units which are uniformly distributed along the circumference are fixed on the surface of one side of the cover plate, the three groups of optical units comprise a first light cup, a second light cup and a third light cup, and a detachable mounting ring is arranged on one side of the cover plate where the optical units are arranged. The LED lamp is characterized in that a mounting seat is arranged on the periphery of the mounting ring, the mounting seat is connected with a lamp holder of a light source, three groups of through light inlets are formed in the mounting seat, the light inlets are used for allowing the light source to directly pass through so as to be opposite to different light cups, the size of light spots can be adjusted, a radial pressure applying unit is connected between the mounting seat and the mounting ring, and the radial pressure applying unit is connected with the mounting ring. The radial pressure applying unit is used for applying damping when the cover plate rotates so as to prevent misoperation of the cover plate. The utility model has the following advantage and effect: the size of the light spot can be adjusted more conveniently and quickly.

The invention discloses a constant value remote dynamic operation and maintenance system and method, and belongs to the technical field of intelligent substation operation and maintenance, and the system comprises a cloud cooperative control unit, an edge agent unit and a terminal constant value processing unit which construct a cooperative operation and maintenance architecture through a communication network. Wherein the cloud cooperative control unit is deployed in a regional regulation and control center, the edge agent unit is deployed in a field station, and the terminal constant value processing unit is integrated in a relay protection device. Constant value remote management is realized through a cloud side-end collaborative architecture, operation and maintenance personnel do not need to be on-site on duty, the problem of time consumption of going back and forth on site in a traditional mode is solved, and manpower and traffic costs are reduced; the whole course of constant value modification, checking and tracing is automatic, manual intervention is reduced, the single constant value adjustment period is shortened from several hours to the minute level, and the operation and maintenance response speed is improved.

The present invention relates to a method and device for identifying inter-turn faults of high-voltage shunt reactors. When the inter-turn fault protection start-up conditions and the zone fault judgment conditions are met, the phase measurement impedance of the reactor meets the low impedance judgment criteria, and the comprehensive harmonic content of the self-generated zero-sequence current at the first end of the reactor is less than the comprehensive harmonic braking coefficient or the waveform of the self-generated zero-sequence current at the first end of the reactor is unsaturated, it is determined to be an inter-turn fault of the reactor. If it is determined to be an inter-turn fault of the reactor, the inter-turn fault protection is activated. Since the harmonic content in the zero-sequence current is high when the core is saturated, and the harmonic content in the zero-sequence current is low when the zone fault occurs, the core saturation fault and the reactor inter-turn fault can be identified by the comprehensive harmonic content and waveform characteristics of the self-generated zero-sequence current at the first end, to prevent the inter-turn protection from malfunctioning due to the core saturation of the reactor when the circuit breaker is opened and closed, so as to improve the reliability of the protection device.

The invention discloses an adjustable positioning tool for welding axle body and air chamber support, comprising a frame, a fixed seat, a swing seat, a driving member, a rolling support group, a sliding platform, a positioning plate for positioning the axle body, a fixed arm, a swing arm cylinder and a chuck for clamping the air chamber support, the fixed seat and the rolling support group are mounted on the frame, the sliding platform is slidably mounted on the fixed seat, the driving member is mounted on the fixed seat and connected to the sliding platform, the swing seat is rollingly connected to the rolling support group, the swing seat is movably connected to the sliding platform, the positioning plate is mounted on the swing seat, the fixed arm is mounted on the swing seat, the swing arm cylinder is mounted on the fixed arm, and the chuck is mounted on the output end of the swing arm cylinder. The positioning tool has the advantages of simple and reliable structure, can realize accurate angle positioning, and can improve welding quality and welding efficiency.

The present application relates to power distribution system technical field, especially to distributed intelligent power distribution network self-healing control method and system.The method comprises the following steps: step S1, real-time collection of distributed intelligent power distribution network operation data; step S2, fault detection; step S3, parallel protection control; step S4, building fault section positioning model and island division model, and positioning fault section according to fault section positioning model, and dividing island according to island division model; step S5, building double-target optimization model; step S6, solving double-target optimization model according to improved ant colony algorithm, and obtaining optimal switch action table; step S7, safety check of optimal switch action table, and self-healing control of distributed intelligent power distribution network according to safety check result; step S8, feedback of self-healing control situation of distributed intelligent power distribution network.The present application improves fault recovery speed, accuracy and reliability of distributed intelligent power distribution network.

This invention discloses a catalytic oxidation tower for waste gas treatment, comprising a fixed oxidation tower with an outlet pipe connected to its side, a fixed circular hole on its side, a support frame embedded in its top, a fixed base plate installed inside the fixed oxidation tower, and a combustion chamber inside the fixed oxidation tower. This invention, by incorporating an air inlet assembly, a rotating assembly, and an oxidation tower, utilizes their coordinated operation. First, the air pump is turned on, and fresh air from the outside is introduced into the combustion chamber inside the fixed oxidation tower through an inlet bend, a fixed circular pipe, and a connecting metal pipe. The fixed circular pipe and connecting metal pipe at its bottom undergo regular circular rotation, thereby distributing the fresh air output from the connecting metal pipe throughout the combustion chamber and fully mixing it with the fuel, effectively and completely burning the waste gas and further improving combustion efficiency.

The invention provides a detection circuit, a chip and a detection method, and is suitable for the technical field of integrated circuits. The detection circuit comprises a relay outlet loop which comprises a relay and is used for driving the relay to execute a closing action or an opening action under the control of a tripping power supply and a first driving signal; the recovery circuit is electrically connected with an outlet loop of the relay and is used for recovering the coil voltage of the relay to obtain a first recovery signal; and the main control loop is used for controlling the tripping power supply to power on the relay outlet loop, outputting a first driving signal to the relay outlet loop, and detecting the action of the relay based on the first recovery signal. According to the embodiment of the application, the action of the relay can be detected, that is, the action of the CPU trip outlet can be monitored, and by controlling and stoping the outlet, the occurrence of action refusal and maloperation of the outlet can be effectively avoided, and the stability of the action of the outlet is improved.

The invention relates to the technical field of power systems and automation thereof, and discloses a power grid operation data real-time acquisition and decision control method, which comprises the following steps: an off-line modeling stage: executing off-line collaborative modeling, generating model parameters, presetting a control strategy set and a threshold value by a central platform layer, and sinking and deploying to an edge domain control layer; in a real-time acquisition and monitoring stage, an edge domain control layer performs real-time acquisition of power grid operation data, operates model parameters to calculate a transient stability margin and identifies a transient instability mode; in the decision control and response stage, the edge domain control layer executes local transient control according to the margin and reports a feedback packet, and the center platform layer receives the feedback packet and executes center side response and closed loop iteration. According to the method, offline modeling and real-time decision execution of an edge domain control layer are combined, a layered and collaborative control closed loop is constructed, and rapid monitoring, accurate control and self-adaptive optimization of the transient events of the power grid are achieved.

The application provides a leg traction support device with independent adjustable angle and contour, and belongs to the technical field of medical instruments. The traction support device comprises a rotating protrusion rotatably connected to the inner wall of a second rotating groove, an end wall of the rotating protrusion is fixedly connected with a supporting plate, an outer wall of a side of the supporting plate away from the baffle is fixedly connected with a guide plate, and the bottom of the supporting plate is fixedly connected with a first elastic plate on the outer wall close to the sliding plate. In the scheme, the leg traction support device can support the legs of patients through the setting of a calf support assembly, and the system realizes real-time and intuitive display of the size of traction force and traction displacement in the reduction process through the integration of a quantitative monitoring assembly.

The invention discloses a converter transformer saturation protection method and device based on small difference current braking, and the method comprises the steps: collecting the network side neutral point zero-sequence current and head end current of a converter transformer, and the valve side head end current of the converter transformer, so as to calculate the periodic peak value of the neutral point zero-sequence current and the instantaneous value of the maximum absolute value of the three-phase small difference current of the converter transformer in a unit period; judging whether a saturation protection criterion is met or not, and if yes, constructing a small-difference differential current braking criterion which comprises a first criterion, setting according to a mean value of a neutral point zero-sequence current period peak value and a second criterion, setting according to a mean value of a neutral point zero-sequence current period peak value; setting according to the absolute value of the difference between any two phases in the instantaneous values when the absolute value of the three-phase small difference current of the converter transformer in the unit period is maximum; when the first criterion and the second criterion are met at the same time, the saturation protection is locked after time delay, and the saturation protection timing is stopped, otherwise, the saturation protection is opened, and the action timing is normally carried out. According to the invention, maloperation can be effectively prevented when excitation inrush current exists and distortion current caused by direct current magnetic bias does not exist.

The utility model discloses an emergency unlocking device for an automobile door, and relates to the technical field of emergency unlocking of automobile doors. Comprising a door lock impact buckle piston cylinder barrel, a connecting rod is arranged on the upper wall face of the door lock impact buckle piston cylinder barrel, an emergency unlocking handle is hinged to the connecting rod, an open groove is formed in the emergency unlocking handle, and a locking piston cylinder barrel is arranged on the upper wall face of the door lock impact buckle piston cylinder barrel. A locking piston bolt column is inserted into the upper wall face of the locking piston cylinder barrel in a sliding mode, and the upper end of the locking piston bolt column is installed in the open groove in a sliding mode. The emergency vehicle door unlocking structure is stable in performance, safe and efficient in design, high-strength stainless steel double springs and double pistons are adopted for clamping and pressing, the situation that a vehicle door is opened by mistake due to violent collision, collision, rolling and bumping of a vehicle is effectively prevented, and the emergency vehicle door unlocking structure adapts to an extreme environment and resists limiting temperature; the emergency unlocking handle adopts a lever working principle, is simple to operate and is suitable for children and old people.

The invention discloses a method and device for reducing loss, preventing explosion and prolonging the service life of a cable sheath protector, and the method comprises the steps: S1, constructing a protection device voltage reduction circuit which comprises a resistor Rg and a capacitor Cg connected with the resistor Rg in parallel, the resistor Rg has a preset resistance characteristic, and the capacitor Rg has a preset capacitance characteristic; s2, constructing an equivalent circuit of the cable sheath protector, wherein the equivalent circuit of the cable sheath protector comprises an equivalent resistor Rcsp and an equivalent capacitor Ccsp connected with the equivalent resistor Rcsp in parallel; and S3, the protection device step-down circuit and the cable sheath protector circuit are connected in series, so that the voltage at the two ends of the cable sheath protector can be automatically adjusted according to the preset resistance characteristic and capacitance characteristic. According to the invention, the operation loss of the cable sheath protector can be reduced, misoperation during power frequency overvoltage and lightning overvoltage is prevented, and the service life of the cable sheath protector is prolonged.

This invention relates to the field of electronic circuit breaker protection technology, specifically to an intelligent overload protection and fault diagnosis method and device for electronic circuit breakers. The device includes: a multi-source data acquisition unit, an edge processing unit, a protection drive execution unit, a human-machine interaction unit, a cloud interaction unit, and a power management unit. This invention solves the problem of existing electronic circuit breaker protection schemes considering only a single factor. By using a dynamic thermal balance equation and a modified inverse-time action expression, it comprehensively considers the effects of ambient temperature, conductor aging, power grid harmonics, and load type, reducing protection action errors. In nonlinear load scenarios, the protection action error is small, avoiding false tripping or failure to trip, and balancing speed and power supply selectivity.

The present application belongs to the technical field of switching power supply, and particularly relates to a switching power supply which is ejected when overheating, and more particularly to a suspension type switching power supply and a use method thereof, wherein the suspension type switching power supply comprises a suspension plugboard, and a power supply body with a base in which a slot is formed for the insertion of the suspension plugboard; wherein the suspension plugboard is provided with plug-in blocks on both sides in a sliding manner; the suspension plugboard is further provided with elastic trigger members; and the elastic trigger members are provided with heat shrink members at the positions corresponding to the plug-in blocks. When the temperature of the power supply body rises to exceed the limit working temperature of the power supply body, the heat shrink members automatically shrink, triggering the plug-in blocks to shrink, so that the elastic trigger members are ejected, the power supply body is ejected from the suspension position, physical isolation is achieved, and the power supply body is prevented from continuing to heat up and igniting surrounding equipment after overheating. Meanwhile, a pure mechanical structure is adopted, the aging or malfunction problems of electronic sensors are avoided, and the failure rate and maintenance frequency are reduced.

A high-pressure straight-through plate-type manual throttle valve adopts the overall structural design of a high-pressure stemless, rising-stem plate valve. A gate throttling component is installed within the valve cavity of the valve body. A valve cover component is fixed above the valve body using sealing gaskets and evenly distributed studs and nuts. Above the valve cover component, a support component and a handwheel drive component are fixed via threads and set screws. A valve stem indicator component passes through the center of the valve cover component, support component, and handwheel drive component, connecting with the gate throttling component within the valve cavity. The handwheel drives the valve stem indicator component and the gate, which houses the valve core, to move up and down, changing the number of throttling orifices in the valve core relative to the fixed valve seat channels on both sides, thus regulating the flow rate. Because both the valve core and valve seat are made of hard alloy material, equipped with a composite elastic sealing ring, and a hard alloy wear-resistant layer is welded onto the outlet channel wall of the valve body, this valve becomes a new type of throttle valve characterized by high pressure resistance, low resistance, low energy consumption, accurate metering, long service life, and ease of production.

The utility model relates to the technical field of terminal blocks, in particular to an anti-maloperation compact terminal block, which comprises a base, the upper end of the base is fixedly connected with a cover plate through bolts, two sides of the base are fixedly connected with side seats through bolts, the two groups of side seats are positioned at the lower end of the cover plate, and a plurality of groups of wiring grooves are formed between the base and the side seats. Wiring bolts are in threaded connection with the interiors of the multiple sets of wiring grooves, terminals and wires are clamped to the side walls of the wiring bolts, the terminals are electrically connected with the wires, multiple sets of reciprocating lead screws are in threaded connection with the lower end of the cover plate, and fastening plates are in threaded connection with the side walls of the multiple sets of reciprocating lead screws; after a wire is connected with the terminal, the cover plate is installed, the reciprocating screw rod is screwed, the fastening plate extrudes the wire, and the side wall of the wire is fixed between the fastening plate and the inner wall of the wiring groove, so that the wire is prevented from being easily loosened from being connected with the wiring assembly under the action of external tension, and maloperation during maintenance of the connector bar is prevented.

This invention discloses a multi-branch area protection method for a DC power supply system in extreme scenarios, comprising: S1: determining the main branch unit from each branch unit in the submarine DC power supply network, deploying a measuring device on the main branch unit, and defining the area between every two adjacent main branch units as the protection area; S2: after determining that a fault has occurred, collecting data after the fault. T w Internal main branch unit m and n Initial fault current IFC: i mn and i nm ,in i mn express m Flow direction n The initial fault current, i nm express n Flow direction m The initial fault current was calculated separately. i mn and i nm The average value of the derivative is used to determine the protection zone where the fault is located based on a preset average value threshold; S3: Calculation i mn and i nm The trend of the derivative, and according to i mn and i nm The initial rise time and rise amplitude of the derivative are used to calculate the fault probability, and the fault location is determined based on the trend and fault probability.