2751results about "Emergency protection detection" patented technology

The invention discloses an intelligent control system for a current transformer, and particularly relates to the technical field of power system monitoring, which comprises a fluctuation identification unit, a redundancy acquisition unit, an error fitting unit, a protection delay unit and a fault response unit, realizes real-time identification and classification of current fluctuation, and has standby path high-speed sampling and fusion signal construction capabilities. The fluctuation trend is judged through error regression, a protection strategy is dynamically set, response is delayed to avoid misoperation, finally, a high-level protection instruction is triggered and a fault event is output when offset overruns or alignment fails, and the data accuracy and the system response stability in the power supply switching process are guaranteed; according to the method, accurate identification of current fluctuation is realized through multi-dimensional feature extraction, data reliability is enhanced by using redundant sampling and error fitting, and by combining delay control and a hierarchical response mechanism, the risk of misoperation is effectively reduced, the fault judgment accuracy and the system protection stability are improved, and the method is suitable for a complex power supply switching scene.

The invention relates to the technical field of power system automation, in particular to a real-time monitoring and fault positioning system for a vehicle-mounted mobile substation. The system comprises a signal acquisition and processing unit which monitors and acquires line parameters and environmental parameters of a transformer substation and traveling wave signals generated when a fault occurs in real time; the fault type identification unit calculates the confidence coefficient of each fault type based on the traveling wave signal so as to judge the fault type generated by the traveling wave signal, and marks the arrival time of the traveling wave head; an algorithm fusion positioning unit preliminarily positions a fault point according to the fault type and the arrival time of a traveling wave head, and then constructs a fitness function through a particle swarm optimization algorithm in combination with line topology and environmental parameters to correct a preliminary positioning error; according to the system, high-precision fault positioning and rapid isolation recovery are realized, the accuracy of fault section division in the complex power distribution network is ensured by modeling switch state and branch change, and misjudgment caused by topological change or equipment overload is effectively avoided.

The invention relates to the technical field of power distribution protection cabinet fault diagnosis, and discloses an intelligent fault diagnosis and rapid isolation method for a power distribution protection cabinet, and the method comprises the steps: synchronously collecting electrical parameters, environment states and equipment motion signals in the cabinet as multi-source monitoring data when the power distribution protection cabinet operates; parameter fluctuation, state change and action time sequence features are extracted after preprocessing, cross-data association analysis is carried out through a multi-dimensional association model to generate an association feature set, a fault diagnosis information set is formed based on the identified abnormal types, fault positions and development trends, an isolation strategy is formulated according to severity levels and influence ranges, and a fault diagnosis result is obtained. And generating a rapid isolation instruction and dynamically adjusting along with fault evolution. According to the method, multi-source data fusion analysis is realized, faults can be accurately diagnosed and rapidly isolated, the operation safety and reliability of the power distribution protection cabinet are improved, and the method is suitable for fault processing of the power distribution protection cabinet in a power system.

The invention belongs to the technical field of fault analysis and monitoring, and particularly relates to an intelligent monitoring and fault isolation method and system for a branch box, and the method comprises the steps: carrying out the multi-physical field data fusion collection of the branch box, and obtaining a spatial-temporal feature matrix; performing dynamic feature extraction on the multi-physical field data of the branch box, and outputting a fused dynamic feature vector of the branch box; obtaining a branch box topological graph structure, and obtaining a branch box node fault probability matrix; building a physically constrained fault propagation model based on the branch box node fault probability matrix, obtaining a pre-isolation set, and outputting a dynamic blocking instruction; taking the pre-isolation set as an initial solution space constraint, outputting a fault type and obtaining an isolation instruction; and setting a branch box topology reconstruction constraint, and performing closed-loop control on each branch box node in combination with the isolation instruction to obtain a switching action sequence of each branch box node and a reconstructed power supply path. Precise monitoring, rapid isolation and intelligent reconstruction of the fault of the branch box can be realized, and the operation and maintenance efficiency of the power distribution network is remarkably improved.

The invention discloses a primary and secondary fusion pole-mounted intelligent circuit breaker. The primary and secondary fusion pole-mounted intelligent circuit breaker comprises a fault detection module, a protection action module, a reclosing module and an information reporting module, the fault detection module collects multi-dimensional electrical quantity through a current transformer and a voltage transformer, and judges a fault and identifies the type in combination with a dynamic normal range and a duration threshold. The protection action module calculates the fault distance based on the correction impedance, judges whether to act or not by combining the current flow direction and the protection range, and selects a protection level according to the fault severity; the reclosing module dynamically sets an observation time window, distinguishes instantaneous or permanent faults through a retest verification mechanism, and adaptively adjusts a reclosing strategy; and the information reporting module uploads fault related information. According to the method, the problems of high misjudgment rate, poor protection selectivity, rigid reclosing logic and the like of a traditional circuit breaker are solved, and the accuracy, quickness and self-healing capability of power distribution network fault processing are remarkably improved.

The present disclosure comprises: a semiconductor switch unit including a first semiconductor switch having a drain terminal connected to a power grid, a second semiconductor switch having a drain terminal connected to a load, and first and second diodes each having a positive electrode and a negative electrode respectively connected to a source terminal and the drain terminal of each semiconductor switch; a bypass circuit which connects the drain terminal of the first semiconductor switch to the source terminal of the second semiconductor switch; and a control unit which, when the power grid is connected to the semiconductor circuit breaker, supplies a current to the load through the bypass circuit and the second diode by closing the bypass circuit while the first and second semiconductor switches are turned off, and which, when preset conditions are met, turns on the first and second semiconductor switches so as to open the bypass circuit so that a current is supplied to the load through the semiconductor switch unit.

The invention discloses a multi-end line pilot protection method and system based on time domain model identification, and relates to the technical field of electrical engineering, and the method comprises the steps: obtaining a three-phase voltage sampling value, a three-phase current sampling value and a switching value of each end of a multi-end line; judging whether each end of the multi-end line meets a protection starting condition or not; if yes, differential voltage variation and differential current are calculated, and correlation coefficients of the differential voltage variation and the differential current are calculated; judging whether the correlation coefficient is within a preset fault threshold range or not; if the correlation coefficient is not within the preset fault threshold range, determining that the multi-terminal line has an external fault, and enabling the protection device not to act; and if the correlation coefficient is within a preset fault threshold range, determining that the multi-terminal line has an internal fault, and enabling the protection device to act to remove the fault. According to the invention, the influence of capacitive current and a power electronic power supply on pilot protection performance is overcome, the operating characteristics of a relay protection device are improved, and safe and stable operation of a power system is ensured.

The invention relates to the technical field of protection device testing, in particular to a verification method of an intelligent comprehensive protection device, which comprises the following steps of: extracting starting time and response time in a tripping state transition sequence of the protection device, calculating execution delay and action segment length, and comparing and identifying an abnormal link based on a state number sequence; the method comprises the following steps: realizing analysis and standard reconstruction of a state logic structure, forming an ordered tripping path, introducing a long short-term memory neural network to carry out time alignment on a state change sequence and a current signal segment, identifying a potential mismatch or abnormal change trend in a state chain through linkage analysis of a state-current abrupt change position, and reconstructing a state path. According to the method, path continuity and dynamic adaptability are enhanced, a random forest is adopted to take device numbers, the number of jump segments and response residual errors as multiple inputs for training modeling, device scores are output through an integrated tree voting mechanism, and recognition sorting of abnormal frequency significant devices is achieved.

The invention relates to the technical field of leakage protection, and provides a self-adaptive mining low-voltage leakage protection method based on working conditions, which comprises the following steps: detecting leakage resistance in real time, and determining the operation condition of a power grid; according to the power grid operation condition, matching a target detection algorithm in preset detection algorithms; wherein the preset detection algorithm comprises an integrated zero-sequence current break variable method, a zero-sequence current and zero-sequence voltage phase method and a zero-sequence current size phase comparison method; according to a target detection algorithm, establishing a unified criterion to coordinate the action logic of the main switch and each branch switch, and determining the electric leakage degree of the electric leakage resistor; and according to the electric leakage degree, performing switch locking on the electric leakage branches in sequence.

The invention relates to the technical field of battery management, and discloses a battery management system with an active monitoring function, which comprises a processor, a battery state monitoring module, an active equalization control module, a performance evaluation module and a fault early warning module. The battery state monitoring module collects various parameters of a battery at different stages, and generates an abnormal signal by using a dynamic threshold algorithm. The active equalization control module adjusts an equalization strategy based on a fuzzy logic algorithm, and a fuzzy rule base can be updated. And the performance evaluation module tracks and evaluates an equalization process, analyzes equalization efficiency and quality, and optimizes an equalization strategy accordingly. The fault early warning module displays abnormal signals in a grading mode and carries out early warning, and the processor is further connected with the aging feature extraction module and the thermal runaway prediction module to achieve battery life prediction and thermal runaway early warning. According to the invention, comprehensive monitoring, efficient equalization control, accurate performance evaluation and reliable fault early warning of the battery are realized, the safety of the battery is improved, and the service life of the battery is prolonged.

The invention belongs to the technical field of electrical safety, and particularly relates to a human body electric shock protection method and system based on multi-parameter fusion, multi-dimensional characteristic parameters are formed by extracting a high-frequency harmonic component, a voltage abrupt change slope and a magnetic field intensity fluctuation value of a residual current waveform, and the weight is dynamically adjusted according to the instantaneous change rate of each characteristic, so that the human body electric shock protection is realized. Generating a weighted feature vector; and a comprehensive criterion value is calculated in combination with a preset rule base and is compared with a dynamic threshold value, so that whether the circuit breaker is triggered to act or not is determined. According to the method, through fusion analysis of a plurality of physical characteristics, the identification capability of the system in a complex electromagnetic environment is improved, the probability of misoperation caused by external interference is effectively reduced, the action accuracy and stability of the circuit breaker are improved, and the power utilization safety and the power supply continuity are guaranteed.

The invention relates to the technical field of motor temperature intelligent control, and particularly discloses a motor temperature monitoring and regulation method and system based on intelligent control and a storage medium, and the method comprises the steps: carrying out data collection circulation: judging whether a sampling period is reached, if yes, reading multi-mode sensing data, and outputting a calibrated temperature value T, and if not, outputting a calibrated temperature value T; if yes, vibration noise is eliminated, the environment temperature is compensated, multimode sensing data is added, and then the calibrated temperature value T is output; intelligent analysis is conducted on the calibrated temperature value T obtained through data collection circulation, if the temperature is normal, data analysis and prediction are conducted, and if the temperature is abnormal, the calibrated temperature value T is analyzed, fault self-diagnosis is conducted, abnormal reasons are judged, the system is controlled to conduct self-adjustment, and temperature early warning is conducted. The problems that in the prior art, monitoring is delayed, regulation and control are rigid, and maintenance is passive, so that energy efficiency is wasted, the failure rate is high, and operation and maintenance cost rises are solved; and a real-time temperature monitoring means and an intelligent control system are lacked.

The invention discloses a voltage acquisition circuit and power supply equipment, the circuit comprises a voltage acquisition end, a near-end sampling unit, a far-end sampling unit, a voltage selection unit and an anomaly detection unit, and the voltage acquisition end is used for acquiring voltage signals. The near-end sampling unit is connected with an output port of the power supply equipment, and the near-end sampling unit is used for collecting the voltage of the output port of the power supply equipment to obtain a first voltage. The far-end sampling unit is connected with the power port of the load and is used for collecting the voltage of the power port of the load to obtain a second voltage. The voltage selection unit is connected with the near-end sampling unit, the voltage selection unit is connected with the far-end sampling unit, the voltage selection unit is connected with a voltage acquisition end, and the voltage selection unit is used for transmitting a target voltage to the voltage acquisition end. The abnormity detection unit is connected with the far-end sampling unit, and the abnormity detection unit is used for detecting a reverse connection fault or a disconnection fault of the far-end sampling unit.

The invention discloses a power supply system of a server, a control method of the power supply system and the server, and relates to the technical field of servers, and the method comprises the steps that a detection control unit is integrated in a power converter, and the detection control unit collects current data of the output end of the power converter and amplifies the current data; whether the output end of the power converter is short-circuited or not is judged according to the amplified current data, so that weak abnormal current signals at the early stage of short circuit are easier to capture, the amplified current data can reach an overcurrent protection point more quickly, and the power converter is turned off before the actual short-circuit current at the output end of the power converter reaches a higher value. Instantaneous current generated by the input end of the power converter is reduced, the risk of triggering power failure of the preceding-stage first electronic fuse is reduced, the technical problem that normal operation of other functions of the server can be affected when the output end of the power brick is short-circuited is solved, and the technical effect that other functions of the server can normally operate when the output end of the power brick is short-circuited is achieved.

The invention provides a power grid fault positioning and intelligent relay protection selective control method and system, and relates to the technical field of intelligent power grids, and the method comprises the steps: collecting the multi-point electrical data of a power grid, adjusting a sampling window and a filtering threshold value according to the operation state of the power grid, and carrying out the data processing; after eliminating the end effect, performing empirical mode decomposition to obtain a fault feature component; inputting the characteristic component into a fault diagnosis model, calculating a fault initial probability based on a Bayesian network, generating multiple groups of fault prediction data in combination with a time sequence evolution rule, and taking a position corresponding to a minimum information entropy value as a fault positioning result; determining a fault area according to a positioning result, establishing a local communication network of relay protection devices in the area, obtaining the operation state of each device, calculating a protection sensitivity coefficient, determining a protection range and a tripping time sequence, generating and sending a control instruction, and realizing selective isolation of the fault area.

A circuit may comprise an electronic switch with a load current path, which is switched between an output node and a supply node and is designed to connect or disconnect the output node to or from the supply node in accordance with a control signal. The circuit further comprises a control circuit which is designed to generate the control signal based on an input signal, and a current monitoring circuit which is designed to receive a current measurement signal that represents the load current flowing through the load current path, and to generate a protective signal, based on the current measurement signal, which indicates whether the output node should be disconnected from the supply node. The circuit further comprises a reverse current detection circuit, which is designed to detect that the load current is flowing in the reverse direction, namely from the output node to the supply node.

Solid-state circuit breakers (SSB) have a fault current limiting function that limit the fault current in power applications. It allows sustained overcurrent for a certain period while preventing the fast fault current increase in dc systems. For the conventional method of using switches alone to limit the current, the high loss results in a short withstand time and low current limiting capability of the SSCBs. Disclosed are various embodiments for a control strategy to use one or more energy absorption components to handle the major part of the energy during a current limiting stage to increase the current limiting capability for series-connected SSCB switching cells.

The invention belongs to the technical field of low-voltage switch cabinet operation control, and particularly discloses an intelligent low-voltage switch cabinet system based on a building intelligent function, which comprises an operation sensing module, a spatial topology module, a fusion diagnosis module, a fault positioning module and a dynamic protection module, current and insulation resistance are synchronously detected at a circuit wiring terminal of the low-voltage switch cabinet, temperature and humidity distribution data of the surrounding environment are collected, and then coupling characteristics between the current and temperature rise are fused. And carrying out visual display of coupling and time sequence correlation in the built three-dimensional heat-electricity correlation topological graph in the switch cabinet by utilizing the time sequence correlation between the insulation resistance and the humidity change, so as to realize comprehensive identification of potential faults. According to the method, the sensitivity and the accuracy of fault identification are effectively improved, early fault symptoms such as poor contact and insulation degradation can be found earlier, the early warning capability of the system is enhanced, and the safety and the stability of operation of the switch cabinet are guaranteed.

An electrical power network employing fault location, isolation and system restoration. The system includes a plurality of switching devices electrically coupled along a power line downstream of a fault interrupting device. The switching devices each have current and voltage sensing capability and the capability to provide pulse tests for detecting fault presence. The fault interrupting device performs reclosing operations, and when the plurality of switching devices detect fault presence a predetermined number of times in coordination with reclosing operations performed by the fault interrupting device and detect loss of voltage, each switching device opens. The fault interrupting device closes when the switching devices open, and the switching devices sequentially pulse test and close from a furthest upstream switching device when detecting return of voltage and no fault presence until a switching device closest to the fault pulse tests and detects fault presence and locks open.

The invention discloses a stator winding grounding fault arc extinction method and system based on grounding transition resistance. The method comprises the following steps: S1, acquiring fundamental voltage of a neutral point and a machine end after normal operation and a grounding fault in real time; s2, calculating a fault phase potential EA1, and calculating a phase angle delta between the fault phase potential EA1 and the neutral point ground voltage UN1; s3, constructing a generator stator winding grounding fundamental wave fault analysis positioning equation, and substituting the measurement and calculation amount to complete fundamental wave fault positioning; s4, if multiple solutions occur in fundamental wave fault positioning, introducing a low-frequency injection quantity check criterion, and screening out a unique correct transition resistance value; and S5, carrying out arc extinction on the fault point of the neutral point of the generator in a high-resistance grounding mode. According to the method, the accuracy and reliability of fault positioning are remarkably improved, the possibility of misjudgment is eliminated, and an accurate compensation basis is provided for arc extinction.

A power management circuit is disclosed that includes a boost converter, a pass transistor, and an overcurrent detect circuit. The boost converter is configured to convert an input voltage into a first power supply voltage. The pass transistor is configured to transfer the first power supply voltage as a second power supply voltage after a predetermined time from a time point at which the first power supply voltage is activated. The overcurrent detect circuit is configured to perform an overcurrent detect operation by sensing a current flowing through the pass transistor. A display device is also disclosed that includes the power management circuit.

According to the SiC MOSFET global short circuit and overcurrent protection circuit and the control method thereof provided by the invention, when a short circuit fault occurs in the SiC MOSFET, the drain current ID is more than several times of the rated current of the SiC MOSFET. When a short circuit occurs, a transistor QDZ of the short circuit detection circuit is switched on by node voltage Vr of the resistance-capacitance filter circuit, a fault signal VFAULT is converted into a low level, grid voltage VGS output by the grid control unit is gradually converted into zero voltage from negative driving voltage VEE, and soft turn-off is performed on the SiC MOSFET; when an over-current fault occurs in the SiC MOSFET, drain current ID is higher than rated current, node voltage Vo of the resistance-capacitance filter circuit lasts for a long time, the maximum value of capacitor voltage Vch of the over-current detection circuit is higher than reference voltage Vref2, a fault signal VFAULT is converted into low level, grid voltage VGS output by the grid control unit is gradually converted into zero voltage from negative driving voltage VEE, and soft turn-off is performed on the SiC MOSFET. According to the invention, high-speed short circuit and over-current fault protection of the SiC MOSFET in all inductance regions of a commutation loop can be realized.

The invention provides a remote intelligent control distribution box, which belongs to the technical field of distribution boxes and comprises a control chip, a wireless communication device, a current monitoring device, a voltage monitoring device, a temperature monitoring device, a leakage protection device, a circuit breaker state monitoring device, a grounding state monitoring device, a humidity monitoring device and a power management device. A control module is arranged in the control chip and is used for acquiring output data of the current monitoring device, constructing a linear temperature rise prediction model, identifying potential fault types by using a decision tree algorithm, operating a lightweight power distribution network sensing model to process dimension-reduced time sequence data and realizing low-calculation-amount feature extraction by adopting a sparse attention mechanism; and when the system health state risk score exceeds a threshold value, a protection strategy is adjusted, and fault precursor characteristics are recorded. The technical problem that early warning of the abnormal state of the power distribution system is difficult to realize in a low-computing-resource environment is solved.

The invention relates to the technical field of electrical fault identification and response, in particular to a relay protection fault identification and response system, which comprises a fault propagation path tracking module, a regional fault monitoring module, a misoperation cumulative effect calculation module, a protection level adjustment module and a fault response module. According to the method, based on the triggering sequence and the triggering interval time of the relay protection device, a malfunction propagation mode is extracted, cascade malfunction associated devices are screened, regional power grid fault risk scores are combined, protection level setting is optimized, the malfunction accumulation trend is calculated through malfunction triggering frequency, and high-malfunction devices are identified. The method comprises the following steps: calculating a protection level adjustment factor, optimizing a relay protection level according to a power grid state, enabling a protection strategy to adapt to different operation conditions, calculating power grid operation state parameters in combination with the adjusted protection level, analyzing stability change, optimizing a relay protection response strategy, enabling a relay protection system to have adaptive adjustment capability, and reducing the sudden fault influence range.

The invention provides a photovoltaic DC circuit breaker fault diagnosis method and system, and relates to the technical field of fault diagnosis, and the method specifically comprises the steps: obtaining key parameters of equipment, calculating the instantaneous power, the current change rate, the temperature change rate and the energy consumption in unit time based on the key parameters, and carrying out the calculation of the instantaneous power when the instantaneous power is calculated, introducing a total harmonic distortion correction power factor; analyzing the correlation between each key index and the fault evaluation index by using a Pearson's correlation coefficient method, and calculating to obtain the fault evaluation index; and a dynamic threshold adjustment mechanism is introduced to judge whether the photovoltaic direct-current circuit breaker has a fault or not. Through a dynamic threshold adjustment mechanism and Pearson's correlation coefficient analysis, the fault diagnosis capability of the photovoltaic DC circuit breaker is improved. Compared with a traditional method, the scheme realizes high-frequency data acquisition and real-time analysis, ensures accurate evaluation of the operation state, effectively identifies potential fault risks, and reduces the probability of equipment damage.

The provided are a method, system, and medium for active arc-extinguishing voltage-current conversion in distribution networks. The method includes: detecting a single-phase-to-ground fault in the distribution network and identifying the target faulty phase; injecting compensating currents into the target faulty phase to reduce its voltage; measuring the residual current at the fault point during the injection of compensating currents and the zero-sequence voltage of the target faulty phase; determining a critical zero-sequence voltage threshold based on the residual current at the fault point and assessing whether this critical value exceeds the present zero-sequence voltage; if so, ceasing the injection of compensating currents into the target faulty phase and instead injecting active arc-extinguishing currents at the neutral point of the distribution network to mitigate ground currents at the grounding points of the distribution network. The objective is to enhance the applicability of arc-extinguishing methods for ground faults in distribution networks.

The invention relates to the technical field of circuit breakers, in particular to a leakage protection action alarm method based on an intelligent circuit breaker, and the alarm method comprises the following steps: collecting a leakage signal of a main loop through a zero-sequence coil, carrying out the dynamic gain adjustment and noise filtering processing of the leakage signal, and generating a preprocessing signal; performing frequency band screening on the preprocessed signal, extracting an electric leakage characteristic signal in a preset frequency band, and obtaining an electric leakage effective value based on the electric leakage characteristic signal; obtaining load classification through the microcontroller unit based on a power signal of a temporary power utilization scene; based on the load classification result, combined with environmental parameters, a dynamic protection threshold is generated through a multi-objective optimization algorithm, and the dynamic protection threshold is used for adjusting leakage protection sensitivity in real time; and when the electric leakage effective value exceeds the dynamic protection threshold value, executing a hierarchical tripping control strategy.

The invention discloses a primary and secondary collaborative planning method based on a novel power distribution system, and relates to the technical field of power system optimization, and the method comprises the following specific steps: constructing a power distribution network model and fault feature analysis, designing an adaptive protection mechanism, realizing a rapid fault processing mechanism, and performing primary and secondary system collaborative planning. And implementing and verifying: implementing a planning method in the power distribution network, installing and debugging related equipment, carrying out field test, and verifying the effectiveness of an adaptive protection mechanism and a fault rapid processing mechanism, the running state of the power distribution network is monitored in real time, and the protection constant value is automatically adjusted according to the monitored fault characteristic parameters, so that the reliability of the power distribution network is improved. Therefore, the adaptive capacity of the system to a complex and changeable operation environment is remarkably improved, the dynamic adjustment mechanism can quickly respond to dynamic factors of new energy output fluctuation and load change, it is ensured that a protection strategy is always matched with the operation state of the system, and the problem of protection maloperation or operation refusal caused by rigid setting of a fixed value is effectively prevented.

The invention discloses a self-adaptive intelligent current limiting and managing method, and relates to the technical field of current limiting. Comprising the steps of collecting real-time current data, historical current data and a system load state of a node, performing feature extraction on the real-time current data and the historical current data of the node, performing analysis and prediction on the collected current data by using an intelligent algorithm, and predicting current according to a current state analysis result; performing risk assessment on the current state in combination with historical current data of the node and a system load condition, analyzing predicted current data, and judging whether the current state has a short circuit risk or not; according to a short-circuit risk judgment result, determining a short-circuit risk node, selecting a current limit strategy, and adjusting current limit by setting a current limit protection value; and continuously monitoring the current state of the short-circuit risk node, adding the node which frequently causes an abnormal state into a blacklist, and carrying out key monitoring or regular maintenance.

The invention belongs to the field of electronic circuits, and provides a zero-cross detection circuit with an anti-crash function, a switching power supply and electronic equipment. The circuit comprises a current output module, a capacitor module, a switch module, a comparison module and a logic module, the capacitor module is connected with the current output module, the switch module and the comparison module, the current output module is connected with the switch module and a power module, and the logic module is connected with the switch module and the comparison module. And the current output module, the capacitor module and the switch module are also grounded. The logic module determines the working state of the circuit through the zero-crossing signal output by the comparison module, when the zero-crossing detection circuit enters a dead halt state, the reset signal is output according to the clock signal and the zero-crossing signal, and the switch module is controlled to be switched on periodically, so that the capacitor module is discharged periodically, the zero-crossing detection threshold value is reduced slowly, and the zero-crossing detection efficiency is improved. Finally, the zero-cross detection circuit can normally trigger zero-cross detection, and the reliability and efficiency of the switching power supply are improved.