132results about How to "Improve safe and stable operation" patented technology

The invention discloses a denitration operation optimization method for an SCR (Selective Catalytic Reduction) system of a tangential firing pulverized coal boiler. The denitration operation optimization method comprises the special steps of using a numerical simulation method; obtaining a velocity of flue gas, an NOx concentration distribution uniformity and a deviation of an outlet of the boiler by means of considering the structure and the operation condition of the boiler as a boundary condition of an inlet of the SCR system; obtaining the velocity of the flue gas, an NH3 / NOx distribution uniformity and a deviation inside the SCR reactor; optimizing and adjusting an ammonia spraying flow of an ammonia spraying nozzle on a flue of the SCR system according to the velocity of the flue gas and the NH3 / NOx; increasing the ammonia spraying flow of the ammonia spraying nozzle corresponding to an area with the larger velocity of the flue gas, and decreasing the ammonia spraying flow of the ammonia spraying nozzle corresponding to an area with the smaller velocity of the flue gas; and increasing the ammonia spraying flow of the ammonia spraying nozzle corresponding to an area with the smaller NH3 / NOx, and decreasing the ammonia spraying flow of the ammonia spraying nozzle corresponding to an area with the larger NH3 / NOx. The denitration operation optimization method provided by the invention can be used for optimizing and adjusting by comprehensively considering the structures and the operation conditions of the boiler and the SCR system, so that the denitration efficiency of the SCR system is improved; the spraying amount and the release rate of ammonia can be reduced; the security, the economical efficiency and the environmental friendliness of the operation of the boiler unit can be improved.

The invention relates to an electric power system line weakness evaluation system and method based on multi-attribute analysis. The system comprises an EMS information obtaining module, a line topology importance degree calculation module, a line correlation coefficient calculation module, an economic loss calculation module, a hidden failure rate calculation module, a line integral weakness calculation module and a weak line screening module. The method comprises the following steps of obtaining trend information and historical information of each line in an electric power system; obtaining the topology importance degree index of each line, the correlation coefficient index of each line, the hidden fault rate index of each line and the economic loss index of each line due to line breaking according to the trend information and the historical information of the line; building an integral weakness index function; performing calculation by using the topology importance degree index, the correlation coefficient index, the economic loss index and the hidden fault rate index of the line as input data of the integral weakness index function to obtain the integral weakness index of each line; and obtaining the weak line in the electric power system through setting the critical weakness index.

The invention discloses an environment meteorological monitoring system for an electric power iron tower based on Internet of things. The system comprises a data acquisition module, a monitoring main unit, a power module, a data transmission module, a client and a server, and is characterized in that the data acquisition module comprises a displacement sensor, an inclination sensor, a torque sensor, an icing detector, a data acquisition instrument, a small observatory and a camera; the small observatory comprises a temperature and humidity measuring module, a wind speed measuring module and a wind direction measuring module; a third generation (3G) and second generation (2G) transmission combined mode is adopted by the data transmission module; and the power module comprises a solar power generation module, a wind power generation module and a storage battery. Based on the idea of an Internet of things technology, the physical state of the iron tower is acquired by the sensors, maintenance personnel timely find the potential safety hazard of the iron tower conveniently, and the fine, preventive and intelligent maintenance of the iron tower is realized; and meanwhile, wind-solar complementary power generation is adopted, so that the stability of the system is ensured.

The invention relates to a safety measure demonstration simulation display method and apparatus for current loop operation of a substation. The method comprises the steps of determining a display caseaccording to a safety measure of normalized current loop operation of the substation; according to the display case, collecting field materials, and according to the field materials, building a substation three-dimensional model required for the whole process of the normalized current loop operation by using specific three-dimensional modeling software; importing the substation three-dimensionalmodel to a virtual reality simulation display platform generated based on a Unity3D virtual reality engine, and based on the substation three-dimensional model, realizing a scene loading and scene resource management function, a scene stereo display and real-time rendering function, a function of man-machine interaction with a virtual reality hardware interaction device, and a safety measure demonstration process simulation display function; and performing safety measure simulation display for the display case on the virtual reality simulation display platform by utilizing a virtual reality simulation display device. Based on a VR technology, various operation process trainings are efficiently finished.

The invention discloses an island dividing method for a power distribution network comprising distribute generation (DG). The island dividing method relates to the field of power supply technologies. The island dividing method implements the optimal island system formation method under the condition of considering output of the DG and load demand uncertainty, can determining the maximum possible island according to real-time situation, and has higher reliability when compared with an island under the condition of certainty. The island dividing method comprises the steps of: establishing a probability model of the DG and loads while considering output of the DG and load demand uncertainty, adopting a Monte Carlo method to carry out sampling tests, and predicting power supply output and load demand; simplifying a topological structure of the power distribution network into an undirected weighted graph while considering importance of the loads; solving an island dividing model by adopting an improved firefly algorithm to obtain a preliminary island; and adjusting and verifying the preliminary island by adopting a probabilistic power flow and sensitivity verification algorithm.

The invention discloses a denitrification operation optimization method of a SCR (selective catalytic reduction) system of a W flame boiler. The denitrification operation optimization method particularly comprises the following steps: acquiring the smoke flow speed and the NOx concentration distribution uniformity and deviation at an outlet of a boiler by considering the structure and the running working condition of a W flame boiler so as to act as inlet boundary conditions of a rear-stage SCR system; adjusting the ammonia spraying flow rate corresponding to the region at which the flue flow speed is slightly high and the NH3 / NOx is slightly low to be low, increasing the number of ammonia spraying nozzles, and adjusting the ammonia spraying flow rate corresponding to a region at which the flue flow speed is slightly slow and the NH3 / NOx is slightly high to be low when the standard criterion that the ammonia spraying flow rate at the upper layer is higher than that at the lower layer, and the ammonia spraying flow rate at the middle is higher than that at two sides is met. According to the invention, the structures and the running situation of the boiler and the SCR system are optimized and adjusted, the denitrification efficiency of the SCR system is improved; the spraying-in quantity and the escape rate of ammonia are reduced.

The invention relates to a disassembling tool table for disassembling an engine brake. The disassembling tool table comprises an upper fixed working table plate, a lower fixed base, jacks, an electric pressure testing pump, a shunt and a hydraulic pipeline, wherein the four jacks are arranged between the upper fixed working table plate and the lower fixed base; a quick coupling is arranged at the lower end of one side of each jack; the four corners of the lower fixed seat are respectively provided with a horizontal adjusting bolt; the electric pressure testing pump is communicated with the shunt by a pipeline; the pipeline is provided with a throttle valve; the hydraulic pipeline is arranged at one side of the shunt; and the hydraulic pipeline is connected with the quick couplings. The disassembling tool table is simple in structure, convenient to assemble and disassemble and safe and reliable to use, and can be used for replacing and maintaining faulty components in a narrow space without maintenance condition, so that the overhauling work load is greatly saved, the faulty components can be maintained in time, the overhauling quality of a maintainer can be improved, and the safe and stable running of a unit can be greatly improved.

The invention discloses a coal blocking early warning and automatic processing device and method for a medium-speed coal mill. The device comprises a first pressure sensor and a flow sensor which are arranged on an inlet pipeline of the coal mill, and a second pressure sensor arranged on an outlet pipeline of the coal mill; the first pressure sensor and the flow sensor are used for collecting the pressure and the flow of an inlet of the coal mill and transmitting the pressure and the flow to a controller; the second pressure sensor is used for collecting the pressure of an outlet of the coal mill and transmitting the pressure to the controller; the controller is connected with an early warning device; the controller is used for comparing the flow and the pressure difference of the inlet and outlet of the coal mill with corresponding threshold values, and if at least one signal is not within a corresponding normal threshold range, a coal blocking signal is output to the early warning device; and the controller is further used for adjusting a hot air adjusting valve to increase the volume of air entering the coal mill or adjusting a cold air adjusting valve to reduce the temperature of the outlet of the coal mill.

The invention discloses a Monte-Carlo simulation based small interference probability risk analysis and simulation method. According to the invention, a corresponding probability distribution model is built so as to be used for studying the small interference probability stability. A large number of operating scenarios are generated by adopting a Monte-Carlo method, and certainty small interference stability analysis is performed at different cross sections, wherein the certainty small interference stability analysis specifically comprises system state space linearization, eigenvalue analysis, key oscillation mode recognition, damping ratio sensitivity calculation and the like. Through performing simulation, calculation and analysis on difference scenarios, a probability density distribution function of the key modal damping ratio is formed by using a mathematical statistics method, and thus the probability of small interference safe and stable operations of a system is acquired by calculation. On the basis, risk evaluation is performed on the system by a risk index based on the damping ratio sensitivity. According to the analysis and simulation method, the small interference probability stability of the system can be evaluated effectively, effectively risk evaluation is performed on the system, and a decision-making basis can be provided for safe and stable operations of the system.

The present invention discloses a photovoltaic power station direct current boosting collection access system and a control and protection method thereof. The system comprises a generation unit and acollection transmission unit, the generation unit formed by a photovoltaic array module and a DC / DC converter outputs a direct current, the direct current is subjected to direct current boosting through a boosting converter, is collected in a combiner box for uniform output and is converted to an alternating current through an inversion converter to be merged into a large power grid. The system fully employs the controllability of the DC / DC converter, the inversion converter and the boosting converter and the reliability of the protection device to avoid the problems in an alternating currentmode so as to improve the safe and stable operation capacity of the photovoltaic power station direct current boosting collection access system. The control and protection method performs control andprotection segmentation and control and protection layering processing of the system to perform accurate control and protection of the system through coordination between the system control and protection subareas and the system control and protection layers so as to achieve safe, stable and reliable operation when the photovoltaic power station accesses the large power grid in the direct currentboosting collection mode.

The invention belongs to the electric power system field, and particularly relates to a generator overspeed protection electric power system electromechanical transient state simulation modeling method. Aiming at generator overspeed protection, a generator overspeed protection model suitable for electric power system electromechanical transient state simulation is built combined with electric power system simulation analysis, action logic judgment of overspeed protection, simulation of a high pressure regulating valve and a middle pressure regulating valve of a steam turbine in a steam turbine model, improvement of a speed regulator and the like are achieved, and a whole generator overspeed protection model is formed so as to achieve the purpose of achieving overspeed protection simulation in electric power system electromechanical transient state simulation software.

The invention relates to a microgrid real-time voltage control method considering micro power source reactive output balance degree. The microgrid real-time voltage control method comprises the steps of establishing a piecewise linear mathematic model at the micro power reactive output upper limit for a universal inverter interface; by considering the micro power source reactive output balance degree, enabling all micro power sources in the microgrid to keep certain adjusting margin so as to better suit voltage deviations caused by random fluctuations of wind power, photo-electricity and load in the micro power sources so as to establish an operating restraint reactive optimized mathematical model including alternating current power flow, node voltage upper and lower limits, and micro power source reactive output upper and lower limits and the like; taking the micro power source reactive output as the control variable and taking the node voltage as the state variable; performing linear approximation on stable running points of an alternating current power flow constraint equation in a system based on a sensitivity relation; removing the state variable from the optimized model; and converting the non-convexity optimizing problem into a series of standard secondary planning sub problems for realizing rapid solving for the model, so that requirement on solving rapidness by real-time control is satisfied.

The invention discloses an intelligent comparison method for main channel information and standby channel information of a power dispatching automation system. The method is characterized by comprising the following steps: first, acquiring the main channel information and the standby channel information in the same set time period in a network mirror port monitoring mode; second, performing shift-reduce parsing on the acquired main channel information and the standby channel information in real time to form events about a main channel and a standby channel, and storing the events of the main channel and the standby channel in a database; third, automatically comparing the events of the main channel and the standby channel to generate a comparison result, if the comparison result is abnormal, triggering to generate an alarm event, storing the alarm event in the database and displaying the alarm event in real time. By the method, the availability of channel data can be improved greatly, and the abnormity of the channel data can be discovered in time, so that the hot standby state of the standby channel is really in an available state at any time, and finally, a powerful guarantee is provided for improving the safe and stable operation of the power dispatching automation system.

The invention discloses a method for optimally controlling influences among a plurality of harmonic sources and the power quality of a smart grid. In the method, for the phenomena of resonance and harmonic amplification among a plurality of power supplies in the smart grid, and the characteristics of the diversity, attenuation property, correlation and the like of harmonic waves, current is represented as a function for a voltage distortion factor and is adjusted according to the characteristics of the harmonic sources to restrict the voltage distortion factor, and the optimal distribution ofpower quality adjustment devices is determined in terms of security, economical efficiency and environmental protection based on a dynamic current plan model to eliminate harmonic superposition and voltage fluctuation so as to realize the optimization of system performance and obtain expected stability and power quality. The method has the advantages of effectively improving the harmonic pollution of the smart grid and providing required power quality for the establishment of the strong smart grid, and also can be applied in the fields of metallurgy enterprises, electric locomotives, aerospace, shipping and the like to promote the industry upgrading of the whole society.

The invention belongs to the fields of power secondary system abnormal state recognition and misoperation prevention and particularly relates to an error prevention system and method for secondary system anomaly recognition of a substation under multiple associated scenes. According to the method, based on normalization of substation information description and normalization of an operation process, an integrated error-prevention function and an error prevention strategy are deployed and configured in devices at all levels of a secondary system comprising devices, a station server and a scheduling server, and information modeling and recognition are performed on the running states of the secondary devices and the secondary system in the substation; and meanwhile, before primary operation and secondary operation on the substation, whether the operation can cause a system anomaly or misoperation is judged through rehearsal according to a power grid topological structure and the running setting state of the secondary devices, and if the system anomaly or the misoperation is caused, warning or forbidding or prompting is actively sent out through analysis, error prevention and remedy are performed on the misoperation or the abnormal running state occurring in the system, and therefore forward intervention on field operation and maintenance work is realized.

The invention relates to the technical field of electric power, in particular to a wind power and photovoltaic consumption prediction and early warning method. The method comprises the following steps: constructing a new energy consumption evaluation model; constructing a new energy installation planning model; and obtaining a calculation result through example simulation. According to the method,factors such as fluctuation of system load and new energy, a power supply structure, power grid peak shaving capability and influence of new energy access to the power grid on the peak shaving capability are comprehensively considered, and the admitting capability of the power grid on the new energy is quantitatively evaluated. On the premise of giving consideration to company benefits and socialbenefits, the situation that blind newly-added installation for increasing the consumption pressure or planning is too conservative and cannot achieve full utilization of clean energy is avoided, thegovernment requirements for energy conservation, environmental protection, clean energy admission and the like in China can be met, reasonable new energy planning is formulated, and the safe and stable operation capacity of the power grid is improved.

The invention discloses a turbonator cooling system provided with a water cooling stator and an inner fan type rotor and relates to a field of motors. According to the invention, by adding an in-stator loop type water channel and an out-of-stator loop type water channel at a tooth top part and a yoke back part of an iron core segment of the stator respectively, arranging a rotor axial ventilating duct in rotor teeth and arranging rotor self-cooling fan blades in the rotor axial ventilating duct, the heat dissipation capability of a rotor area and a stator area is enhanced effectively, the utilization rate of cooling fluid in the turbonator is improved, the highest temperature of the stator area and the stator area are reduced substantially and the capability of safe and stable operation of the turbonator is improved.

The invention discloses a coordinated control method for a wind power DC transmission system under a single pole blocking fault. The method is characterized in that control of a rectifier station non-faulty pole converter, a matched converter station reactive power compensation device, a doubly-fed wind turbine network side converter and a machine side converter is referred, the control strategy of the doubly-fed wind turbine network side converter is that calculated ird and irq are respectively sent to an inner loop control link of a rotor side converter to obtain a control voltage under a synchronous speed rotating coordinate system, the control voltage is subjected to coordinate transformation to be a control voltage under a static two-phase alpha and beta coordinate axis system, the control voltage and a DC bus voltage are subjected to space vector modulation to generate a rotor-side converter PWM driving signal to suppress a machine terminal overvoltage. The method is advantaged in that when a system has a single-pole blocking fault, a transmission end converter station, the reactive power compensation device and a DFIG wind farm make full use of the reactive power adjustmentcapability to minimize the fault overvoltages at a common connection point of a transmission end and a DFIG wind farm machine terminal to improve system security, stability and fault traversal capabilities.

The invention discloses a method and a device for controlling a virtual synchronous generator of a photovoltaic power station. Firstly, load shedding control is carried out on each photovoltaic generation unit participating in virtual synchronous generator control inside the photovoltaic power station; then, voltage, current and frequency signals at a grid-connected point of the photovoltaic power station are acquired; a virtual synchronous generator controller is used for realizing photovoltaic power station virtual synchronous generator control, and active and reactive power reference values of each photovoltaic generation unit are acquired; a power instruction obtained by the virtual synchronous generator controller is issued to each photovoltaic generation unit through a fiber network; and each photovoltaic generation unit receives the power instruction, the power reference value is tracked, and power control on the photovoltaic power station is realized. The above method realizes the photovoltaic power station virtual synchronous generator function, the safe and stable operation ability of the photovoltaic power station is enhanced, and the voltage and frequency control ability of the photovoltaic power station can be exerted.

The invention discloses an AGC control method for an asynchronous power grid with multiple DC lines. When an AGC control model of a provincial control area is established, DC converter stations and matching units under the jurisdiction of a power dispatching control sub-center inside a provincial power grid are used as AGC internal equipment of the provincial control area, and the units and DC lines under the jurisdiction of the power dispatching control sub-center are not considered as connecting line borders. The invention aims at reducing the influence of the measurement quality on the AGCof the provincial control area after the number of equipment of the power dispatching control sub-center increases day by day. The problem that the failure of the equipment of the power dispatching control sub-center may lead to the reverse regulation of AGC in the provincial control area is solved. Through coordinated control on the power dispatching control sub-center and the AGC of the provincial control area, two-level dispatching integrated coordinated control is ensured, and the daily operation pressure of dispatchers is reduced. Therefore, the operation efficiency of the power grid is improved, and the safe and stable operation ability of the power grid is enhanced.

An apparatus monitors the state of charge (SOC) of a flow battery system. The monitoring method include determining SOCs of at least two pairs of different monitoring positions. A pair of monitoring position may be located inside of an anode electrolyte storage tank (2) and inside of a cathode electrolyte storage tank (3), or inside of an anode electrolyte outlet pipeline (6) of a stack and inside of a cathode electrolyte outlet pipeline (7) of the stack, or inside of an anode electrolyte inlet pipeline (8) of the stack and inside of a cathode electrolyte inlet pipeline (9) of the stack. The SOCsum of the flow battery system is acquired according to the SOCs corresponding to different pair of monitoring positions, respectively. The method ensures acquiring an SOC monitoring result timely and accurately.

The invention provides an AC-DC hybrid power grid dynamic reactive power optimization control method based on voltage sensitivity, and relates to the technical field of power system reactive voltage control. Directed at an AC-DC hybrid power grid in a certain region in China, a dynamic voltage stable state model is established for a new energy power supply and matched dynamic equipment thereof, and the dynamic reactive voltage characteristic of a large grid frame is analyzed by using a decentralized continuous reactive power optimization decoupling calculation and particle swarm optimization calculation voltage sensitivity method. According to the invention, two forms of an optimization algorithm and software state analysis are provided to analyze the voltage sensitivity of the power grid, so that the optimization process of the dynamic reactive voltage is realized from two perspectives of a distributed phase modifier and local reactive power compensation equipment, and the optimal distribution of the reactive power compensation equipment and the operation solution of weak points of the voltage sensitivity are realized; the voltage robustness of the system and the operation efficiency of reactive power equipment are improved, the voltage characteristics of the AC-DC hybrid power grid are reflected more accurately, and the method has important significance for improving the safe and stable operation of the power grid.

The invention discloses a VSG control method under a grid voltage symmetrical drop fault, which includes the following steps: S1, grid voltage information at a tie line is collected and transmitted to a local controller of a VSG in a micro grid; S2, active and reactive power reference instructions and a voltage reference instruction are calculated when a grid voltage symmetrical drop fault is detected; S3, a grid-connection small signal cable at the operation point of the fault is established, control parameters satisfying given dynamic performance and stability performance indexes are calculated, active power and voltage rated values are synchronously switched to the active power and voltage reference instructions, and the control parameters are switched; S4, the local collector collects local voltage and current information and establishes a voltage loop control model, a fault current limiting control model and a current loop control model; and S5, when the fault is detected to be eliminated, smooth transition from a fault state to a normal state is realized by adjusting the phase angle. Smooth and fast transition of the VSG from a fault operation state to a normal operation state after recovery of grid voltage can be realized.

The invention discloses a capacity allocation method of a wind power plant dynamic reactive power compensation device based on low voltage ride through. The method sequentially includes the following steps that n fault combination conditions are made according to a set wind power plant low voltage ride through requirement; three-phase shortcircuit faults are set in a power grid, grid connection points sequentially operate under the n fault combination conditions made in the step S1, and the minimum dynamic reactive power compensation capacities Q1 used for enabling a wind power plant to return to operate normally after faults happen are acquired respectively; the maximum value of the Q1 is chosen as the wind power plant dynamic reactive power compensation allocation capacity. The capacity allocation method of the wind power plant dynamic reactive power compensation device based on low voltage ride through is suitable for existing grid connection wind power plant planning, and beneficial to improving the transient voltage stability of a regional power grid of the wind power plant and the low voltage ride through capacity of the wind power plant.

The invention discloses a statistical analysis system based on intelligent substation configuration data management and control, which comprises a data import module, which is used for storing the data information uploaded by users and carrying out classification management. The configuration file parsing module receives the calling command and the incoming calling parameter of the data importingmodule, executes the corresponding API interface, parses the ICD, CCD or SCD file, and converts the parsing result into the XML file of the standard format to store; the configuration file parsing module receives the calling command and the incoming calling parameter of the data importing module, executes the corresponding API interface, and parses the ICD, CCD or SCD file, and converts the parsing result into the XML file of the standard format. The process management module is used for defining and managing the execution process of the configuration data of the intelligent substation; a secondary equipment statistics module: take the secondary equipment in the system as the analysis object to count the proportion of secondary equipment of each manufacturer and the statistical informationof the damage rate of secondary equipment; intelligent substation distribution statistics module: used for substation geographical distribution data statistics; It realizes the organic combination ofintelligent substation process control and automation check, and the deep mining and effective utilization of control data.

The invention discloses a virtual synchronous generator control method of a direct current micro-grid energy storage unit DC-DC converter. The virtual synchronous generator control method comprises a signal measurement step, a direct current busbar voltage reference value calculation step, a double-closed loop control step, a duty ratio calculation step, and a PWM modulation step. By adopting the virtual synchronous generator control method, a voltage regulation capability of an energy storage unit is realized, and at the same time, by introducing the inertia and damping external characteristics of the conventional synchronous generators, the safe and stable operation of the direct current micro-grid is facilitated.

The invention relates to the technical field of electric power, in particular to a multi-energy system combined installation planning method based on global benefit maximization. The method comprisesthe steps of constructing a pumped storage power station joint planning model; solving the planning model by using a two-layer optimization method; and obtaining a system planning result by using a Cplex optimization software. According to the method, the wind power absorption capacity of the northern areas can be improved, the disturbance rejection capacity and the wind power absorption capacityof the system are improved on the premise of considering the company benefits and social benefits, and the peak regulation capacity of the system after wind power grid connection is improved. The method also consider the factors, such as the fluctuation of the system load and the wind power, a power supply structure, the power grid peak shaving capacity, the influence of the wind power on the peakshaving capacity after the power wind accesses in a power grid, etc., comprehensively, and can quantitatively evaluate the limitation degree of the power grid peak shaving on the wind power acceptance capacity. The method is helpful for meeting the energy-saving and environment-friendly, clean energy admission and other political demands in China, and can be used for improving the power grid power supply structure in China, reducing the power generation cost and improving the safe and stable operation capability of the power grid.

The invention provides a generalized driving energy analysis method for vibration coupling of a large regional power grid and provincial power grids. The method comprises the following steps: (1), building a static power flow model and a stable calculation model of an interconnected power grid, (2) scanning a small interfering frequency domain characteristic root, and screening a leading electromechanical oscillation mode of the extra-high voltage interconnected power grid and the provincial power grids, (3) determining a call wire between an extra-high voltage communication channel falling point power grid and other provincial power grids, (4) defining generalized driving energy of large-disturbance oscillation of the extra-high voltage power grid and the provincial power grids, (5) determining the relevance of the vibration coupling of the extra-high voltage power grid and the provincial power grids, and (6) analyzing factors which affect the generalized driving energy, and making relevant measures. By means of the method, the vibration coupling characteristics between the extra-high voltage power grid and the provincial power grids are analyzed, on the basis, the measure of reducing the generalized driving energy to relieve the relevant coupling effect is brought forward, and safe and stable operation capacity of the interconnected power grid crossing a large region can be improved.

Disclosed is an alternating current arc fault detection method and system based on multiple linear time-frequency conversions. Improved S transformation and one-dimensional rapid short-time Hartley transformation analysis are carried out on collected alternating current system loop current signals, and characteristic quantities related to arc faults are selected according to the consistency of normal state characteristic values and the difference between the normal state characteristic values and arc fault state characteristic values; redundant arc fault characteristic quantities are screenedout according to the characteristic change trend, the obtained time-frequency characteristic quantity set is input into a K-means clustering model with a binary clustering center, the current state ofthe system can be judged, and when an arc fault cut-off standard is triggered, an action signal for cutting off a corresponding fault branch is sent out, and an alarm is given out. Time-frequency information of the alternating-current arc fault is extracted through multi-linear time-frequency conversion, it is ensured that the alternating-current system arc fault under different nonlinear load conditions can be effectively removed, and the safe and stable operation capacity of the alternating-current system is improved.