A high-power dc appliance detection method

Abstract

The application relates to the technical field of high-power direct-current electrical equipment detection, and discloses a high-power direct-current electrical equipment detection method, which comprises the following steps: calculating the track boundary and track speed of a construction worker when the worker is maintaining equipment based on a three-dimensional coordinate system; performing a space hierarchical sharpness modeling strategy, dividing a plurality of concentric spherical layers on the equipment according to a center point, identifying a sharp end based on a set area threshold, and calculating the sharpness of the sharp end; performing a main electric arc field control guiding strategy, calculating the field control risk of each sharp end based on the track boundary, the sharpness of the sharp end and a unit vector; performing an electric arc offset safety protection strategy, monitoring the distribution and diffusion speed of the electric arc boundary in real time, judging whether the electric arc is offset, and immediately cutting off the power supply when the electric arc is offset and it is predicted that the electric arc will cause danger to the construction worker; and performing an electric arc dispersion risk prediction strategy, predicting the dispersion of the electric arc in a future period, and starting safety measures based on the dispersion, so that the safety level of the construction worker's work is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-power direct-current electrical equipment detection, in particular to a high-power direct-current electrical equipment detection method. BACKGROUND

[0002] High-power direct-current electrical equipment is prone to produce rapid spreading body arcs when it fails in the enclosed space of the power distribution cabinet. Due to the narrow space and insufficient lighting, it is difficult for construction personnel to timely perceive the arc position, which poses a serious safety hazard. It is of great significance to effectively monitor and control the arc spread and ensure the safety of construction personnel.

[0003] In an enclosed or insufficiently lit environment, high-power direct-current electrical equipment often produces penetrating arcs when it fails. Since direct-current arcs have no zero-crossing point, the arc is persistent and prone to unstable spread, posing a serious safety threat to the equipment and construction personnel. Existing technologies rely on fixed magnetic field structures or physical devices to guide and stabilize the arc path, but lack dynamic response to the actual moving trajectory of construction personnel and do not optimize the arc initiation strategy in combination with the structural characteristics of the equipment. They cannot reflect the spatial relationship between the arc and the personnel position in real time, and there is a safety blind area. Existing detection methods mostly focus on single-point or local signals, lack continuous tracking and dynamic analysis of arc boundary spread and speed changes, and cannot synchronize with the moving direction and speed of construction personnel. When the moving direction of personnel and the spreading direction of arc tend to be the same, traditional methods are difficult to discover the risk in time; especially the tiny arc that is difficult to detect with the naked eye, its instantaneous spread may also cause human body injury without warning. Therefore, in the maintenance of high-power direct-current equipment, the existing technology is difficult to achieve coordinated protection of personnel trajectory and arc dynamics.

[0004] The present application provides a high-power direct-current electrical equipment detection method to solve the problems in the background art. SUMMARY

[0005] The present application provides a high-power direct-current electrical equipment detection method to facilitate solving the problems mentioned in the background art.

[0006] The present application provides the following technical solution: a high-power direct-current electrical equipment detection method, comprising:

[0007] When high-power direct-current electrical equipment fails to produce a body arc phenomenon, a magnetic field deflection force is applied to the equipment to maintain the arc within a predetermined area, specifically:

[0008] A three-dimensional coordinate system is established in the space where the equipment is located;

[0009] The trajectory boundary and trajectory speed of the construction personnel when maintaining the equipment are calculated based on the three-dimensional coordinate system;

[0010] The center point of the equipment is obtained;

[0011] The spatial hierarchical sharpness modeling strategy is executed to divide multiple concentric spherical layers on the device according to a center point, identify a tip based on a set area threshold, and calculate the sharpness of the tip;

[0012] A unit vector corresponding to the trajectory direction of the construction personnel when maintaining the device is obtained;

[0013] The main arc field control guidance strategy is executed to calculate the field control risk of each tip based on the trajectory boundary and the tip sharpness and the unit vector, and determine a target tip;

[0014] The field control risk is the probability of failure to maintain the arc within a predetermined area;

[0015] A magnetic field deflection force is applied to the device to maintain the arc within a predetermined area formed by the target tip;

[0016] When the construction personnel maintain the device:

[0017] The arc offset safety protection strategy is executed to monitor the distribution and diffusion speed of the arc boundary in real time, determine whether the arc is offset, and immediately power off when the arc is offset and is predicted to pose a danger to the construction personnel;

[0018] When the arc is offset and does not pose a danger to the construction personnel:

[0019] The arc dispersion risk prediction strategy is executed to predict the dispersion of the arc in a future period, and based on the dispersion, initiate safety measures including the main arc field control guidance and power off.

[0020] Optionally, the trajectory boundary and trajectory speed of the construction personnel when maintaining the device are calculated based on a three-dimensional coordinate system, including:

[0021] Optionally, one coordinate axis in the three-dimensional coordinate system is taken as a reference axis, and multiple equidistant parallel lines are divided on the surface of the device in a direction perpendicular to the reference axis;

[0022] For any construction personnel, the moving trajectory area of the construction personnel when maintaining the device is collected, and the moving trajectory area intersects each parallel line to obtain two intersection points on each parallel line;

[0023] The two outermost intersection points on each parallel line are named as boundary point one and boundary point two, respectively;

[0024] Boundary point one on all parallel lines is connected to form a trajectory boundary curve one, and boundary point two on all parallel lines is connected to form a trajectory boundary curve two;

[0025] The trajectory boundary curve one and the trajectory boundary curve two on the surface of the device are taken as the trajectory boundary of the construction personnel when maintaining the device;

[0026] Record the time length of each construction personnel moving along the moving track area, and calculate the mean value of the time length to obtain t; Obtain the number of parallel lines And the distance between adjacent parallel lines ;

[0027] Calculate the trajectory speed of the construction personnel : .

[0028] Optionally, the execution space hierarchical sharpness modeling strategy is to divide a plurality of concentric spherical layers on the device according to the center point, identify the sharp end based on a set area threshold, and calculate the sharpness of the sharp end, comprising:

[0029] Select a plurality of discrete points on the surface of the device, and obtain the coordinates of each discrete point in a three-dimensional coordinate system;

[0030] Calculate the mean value of the x-axis coordinate value, the mean value of the y-axis coordinate value, and the mean value of the z-axis coordinate value of each discrete point as the coordinate value of the center point of the device in the three-dimensional coordinate system;

[0031] Divide a plurality of concentric spherical layers on the device with the center point of the device as the center of the sphere, and the interval between each concentric spherical layer is the layer interval;

[0032] The discrete points on the surface of the device are intercepted by the concentric spherical layers to form a plurality of spatially separated segment regions;

[0033] Calculate the area of each segment region, specifically:

[0034] Calculate the mean value of each coordinate axis coordinate of all discrete points in the segment region in the three-dimensional coordinate system to obtain the coordinate value of the center point of the segment region;

[0035] Calculate the Euclidean distance from the center point of the segment region to each discrete point on the segment region, and calculate the mean value of all Euclidean distances, denoted as ;

[0036] Calculate , wherein is the area of the segment region;

[0037] Set an area threshold ;

[0038] If , the segment region is a sharp end structure region of the sharp end structure intercepted by the concentric spherical layer of the sharp end structure.

[0039] Optionally, the execution space hierarchical sharpness modeling strategy is to divide a plurality of concentric spherical layers on the device according to the center point, identify the sharp end based on a set area threshold, and calculate the sharpness of the sharp end, further comprising:

[0040] obtaining a center point of each tip structure region, and establishing a normal vector of the tip structure region;

[0041] The normal vector is determined by a center point of the device and a center point of the tip structure region, and the center point of the device points to the center point of the tip structure region;

[0042] The normal vectors of the optional two tip structure regions and ;

[0043] Calculate the included angle of the normal vectors , wherein, is the dot product of the normal vectors, is the length of the normal vector;

[0044] Set the included angle threshold , if , the two tip structure regions correspond to the same tip;

[0045] Calculate the sharpness of the tip , wherein, is the total number of tip structure regions corresponding to the tip.

[0046] Optionally, the execution of the main electric arc field control guidance strategy, based on the trajectory boundary and the tip sharpness and the unit vector, calculates the field control risk of each tip, and determines the target tip, comprising:

[0047] For each tip:

[0048] Obtain the normal vectors of all tip structure regions corresponding to the tip, calculate the average value of the normal vectors, and record the average value as the tip structure vector ;

[0049] Obtain the unit vector corresponding to the moving direction of all maintenance personnel when maintaining the device, calculate the average value of the unit vector, and record the result as the moving vector ;

[0050] Calculate the included angle of the tip structure vector and the moving vector , wherein, is the dot product, is the length;

[0051] Obtain the tip structure region farthest from the center point of the device in all tip structure regions corresponding to the tip, obtain the center point of the tip structure region, and record it as the tip point;

[0052] Optionally, a plurality of boundary points on the trajectory boundary curve one and the trajectory boundary curve two of the trajectory boundary;

[0053] Calculate the Euclidean distance of the cusp and each boundary point, and record the minimum Euclidean distance as ;

[0054] Normalize the cusp sharpness, included angle and Euclidean distance, and update them to normalized values;

[0055] Calculate the field control risk of the cusp , , wherein, are the weights of the cusp sharpness, included angle and Euclidean distance , respectively, is a positive number for preventing the denominator from being 0;

[0056] Record the cusp with the lowest field control risk as the target cusp, and construct the space tubular domain where the target cusp is located as the predetermined area, taking the cusp structure region corresponding to the largest area of the target cusp as the reference.

[0057] Optionally, the electric arc deviation safety protection strategy is executed, the distribution and diffusion speed of the electric arc boundary are monitored in real time, it is judged whether the electric arc deviates, and when the electric arc deviates and it is predicted that the construction personnel is in danger, power is immediately cut off, including:

[0058] When it is detected that the electric arc is not maintained in the predetermined area, it is determined that the electric arc deviates;

[0059] On the electric arc boundary, a plurality of detection points are optionally arranged, and for any one detection point:

[0060] The diffusion speed of the detection point is monitored in real time , and a power-off test experiment is performed:

[0061] Record the acceleration of the detection point when the power is cut off as ;

[0062] Calculate the time length when the diffusion speed of the detection point decreases to 0 , ;

[0063] Calculate the displacement of the detection point when the diffusion speed decreases from to 0 , ;

[0064] Obtain the displacement of the detection point caused by the residual electric energy after the power is cut off , and and are equal in direction;

[0065] Calculate as the diffusion displacement of the detection point after the power is cut off;

[0066] Calculate the time length Displacement of the inner construction worker movement , ;

[0067] Map the diffusion displacement of the detection point to the displacement of the construction worker Get the mapping displacement parallel to the displacement direction of the construction worker ;

[0068] Get the end position of the displacement Get the end position of the mapping displacement and the distance between the two end positions, and record the smallest distance as ;

[0069] Set the distance threshold ;

[0070] If , the arc offset is dangerous to the construction worker, and the power is immediately turned off

[0071] If , the arc offset is not dangerous to the construction worker

[0072] Optionally, the arc dispersion risk prediction strategy is executed to predict the dispersion of the arc in the future period, and safety measures are started based on the dispersion, including:

[0073] Get the arc intensity at each discrete point on the surface of the device ;

[0074] Calculate the Euclidean distance of each discrete point from the boundary point on the arc boundary, and get the minimum distance as the nearest distance of each discrete point from the arc boundary ;

[0075] Calculate , where is the dispersion of the arc at the current time

[0076] Calculate the change rate of dispersion , where is the change amount of dispersion in length

[0077] If the change rate , the dispersion shows an increasing trend

[0078] If the change rate , the dispersion shows a weakening trend

[0079] Optionally, the arc dispersion risk prediction strategy is executed to predict the dispersion of the arc in the future period, and safety measures are started based on the dispersion, further including: ​​

[0080] Real-time monitoring of the diffusion acceleration of detection points on the arc boundary ;

[0081] Calculate the distance of the detection point diffusion in the future period of time from the current time backwards in time ;

[0082] , calculate the mean distance to obtain ;

[0083] If and , then immediately power off;

[0084] If and , then execute the main arc field control guidance;

[0085] If and , then execute the main arc field control guidance;

[0086] If and , then maintain the status quo.

[0087] The present application has the following advantages:

[0088] 1. The high-power DC electrical equipment detection method, by applying a magnetic field deflection force when an arc fault occurs in the high-power DC equipment, limits the arc to a predetermined area, and combines personnel trajectory, sharpness modeling and field control guidance in a three-dimensional coordinate system, to realize full-link safety protection from spatial positioning, risk calculation to dynamic control. Predict the risk position at an early stage of arc formation, and actively intervene in the arc direction through the magnetic field to reduce the probability of out-of-control diffusion. The moving direction and speed of the construction personnel are coupled with the real-time analysis of the arc spatial distribution, so as to prevent the personnel from entering the danger zone, thereby significantly reducing the risk of personal injury and improving the operation safety level and continuous operation ability of the high-power DC equipment.

[0089] 2. The high-power DC electrical equipment detection method, by parallel line segmentation and intersection extraction in a three-dimensional coordinate system, accurately obtains the activity boundary and average moving speed of the construction personnel on the surface of the equipment. Compared with the scheme of only using camera or single-point positioning, it has higher anti-shielding and stability. The advantages are: ① The distance relationship between the construction personnel and the specific part of the equipment can be quantified, which is convenient for subsequent risk prediction; ② The moving speed data can provide reaction time evaluation for emergency power-off or magnetic field guidance; ③ The boundary curve can be directly compared with the arc space range to realize real-time collision risk judgment. It is suitable for complex equipment surfaces and multiple construction personnel parallel operation scenes, and guarantees data accuracy and real-time performance.

[0090] 3、The high-power DC electrical equipment detection method uses the center point of the equipment as the reference, adopts concentric spherical layer segmentation and area threshold screening, quickly identifies the structural tip, and quantifies the sharpness. The high-risk discharge position is extracted efficiently. The advantages include: ① The sharpness quantification can be directly associated with the arc field control risk model, improving the accuracy of risk calculation; ② The concentric spherical layer segmentation avoids the shape misjudgment caused by the misalignment of the local coordinate system; ③ The model can be extended to different equipment shapes and sizes, and has universality. It provides accurate spatial input parameters for main arc position prediction and control. Through the construction and angle determination of the normal vector of the tip, multiple local tip structure regions are merged into the same tip entity, and the sharpness is calculated based on the number of tip corresponding structure regions. Compared with judging the sharpness only by local curvature or single segment area, this strategy based on spatial vector and global merging can reduce false detection and repeated counting.

[0091] 4、The high-power DC electrical equipment detection method, the arc offset safety protection strategy can accurately determine whether the offset is a threat to the construction personnel and decide whether to immediately power off when the arc deviates from the predetermined area through diffusion speed, acceleration and personnel displacement mapping. Compared with the simple "offset power off", this scheme avoids unnecessary downtime, reduces false actions, and improves system stability. By predicting the future collision point of the arc and the personnel trajectory, measures are taken in advance, and the power-off judgment is based on the quantitative spatial distance and speed relationship, which is scientific and verifiable; it ensures personal safety, and also considers the continuity and efficiency of equipment operation.

[0092] 5、The high-power DC electrical equipment detection method, the arc dispersion risk prediction strategy quantifies the diffusion degree of the arc on the equipment surface by calculating the nearest distance and intensity distribution of the arc boundary, and analyzes the trend of dispersion to judge the future risk. The dispersion index can reflect whether the arc is concentrated or diffused, which helps to judge the potential range of contact; trend analysis provides early warning capability in the time dimension, supporting the deployment of preventive measures in advance; it can be used as an auxiliary decision basis for field control strategy and power-off strategy, improving the initiative and accuracy of protection. When the prediction result shows that the arc will approach the personnel trajectory in the future period, power-off or guided measures are triggered immediately. Action can be taken before danger occurs, maximizing reaction time; accurate quantification of future risk reduces frequent intervention due to misjudgment; it provides intelligent and dynamic safety management capability for high-power DC equipment operation and maintenance, significantly improving the safety level of operation. BRIEF DESCRIPTION OF DRAWINGS

[0093] Figure 1 The figure is a flowchart of the method of the present application.

[0094] Figure 2 The figure is a schematic diagram of the end position relationship. DETAILED DESCRIPTION

[0095] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0096] Embodiment one, refer to Figure 1 A high-power DC electrical equipment detection method, comprising:

[0097] When a high-power DC electrical equipment fails to generate a body arc phenomenon, a magnetic field deflection force is applied to the equipment to maintain the arc in a predetermined area, specifically:

[0098] Existing statistics show that about 15%-20% of the safety accidents of construction personnel in the environment of sealed DC electrical equipment such as power distribution cabinets are caused by arc faults, and more than 60% of the accidents occur in areas with insufficient lighting and narrow space, and the accident consequences are often aggravated because the arc diffusion is not discovered in time. The existing arc guiding structure is designed for open space or specific guiding channel, and it is difficult to effectively adapt to the actual construction situation of limited personnel activity and limited vision in a sealed environment, lack of real-time risk assessment and magnetic field active guiding control of the trajectory of the construction personnel and the sharp structure of the equipment, and it is difficult to meet the urgent needs of maintenance safety of high-power DC equipment in sealed space power distribution cabinets.

[0099] Considering that the environment of high-power DC electrical equipment such as power distribution cabinets is usually a sealed space, the moving path of the construction personnel is relatively stable and limited by space during maintenance, and the lighting conditions inside the power distribution cabinet are generally dim, and the construction personnel cannot observe the arc conditions of all positions of the equipment. Under such circumstances, the body arc generated at the time of failure is prone to local small arc diffusion, and the construction personnel often have difficulty in discovering and judging the actual diffusion range of the arc in time. Even a very small arc deviation or diffusion may cause serious safety accidents, causing burns, electric shock of construction personnel, and even secondary damage to equipment and power failure accidents.

[0100] The diffusion speed of the body arc generated by high-power DC electrical equipment is extremely fast, and a large range of deviation is often completed within milliseconds, making it difficult for manual and traditional monitoring methods to achieve timely and accurate identification and response, and there is obvious hysteresis.

[0101] A three-dimensional coordinate system is established in the space where the equipment is located;

[0102] The trajectory boundary and trajectory speed of the construction personnel when maintaining the equipment are calculated based on the three-dimensional coordinate system, including:

[0103] The construction personnel wear gloves with IMU sensors, combined with the camera in the cabinet to collect data, and the system fuses the positioning information of the two to generate high-precision three-dimensional trajectory points. The system performs spatial layering and boundary extraction on the trajectory points to form a trajectory boundary curve. Combined with the timestamp, the average trajectory length and speed are calculated for subsequent risk assessment and field control guidance strategy.

[0104] Optionally, one coordinate axis in the three-dimensional coordinate system is taken as the reference axis, and 6 equidistant parallel lines are divided on the surface of the equipment in the direction perpendicular to the reference axis, and the distance between each parallel line is 0.2m;

[0105] For any construction personnel, the moving trajectory area of the construction personnel when maintaining the equipment is collected, and two intersection points are obtained by intersecting the moving trajectory area and each parallel line;

[0106] The two outermost intersection points on each parallel line are named as boundary point one and boundary point two, respectively. The moving trajectories of multiple construction personnel are different, and in order to protect the construction personnel to the greatest extent, the widest trajectory boundary is considered;

[0107] Connecting all the boundary points one on the parallel lines forms a trajectory boundary curve one; connecting all the boundary points two on the parallel lines forms a trajectory boundary curve two;

[0108] The trajectory boundary curve one and the trajectory boundary curve two on the surface of the equipment are taken as the trajectory boundary of the construction personnel when maintaining the equipment.

[0109] For the high-power DC electric appliance equipment fault arc problem generated by the construction personnel using arms for maintenance operation in the closed space such as power distribution cabinet. The construction personnel mainly stretch, move and operate the equipment in the narrow space, resulting in that the activity trajectory has strong spatial limitation and path stability.

[0110] In view of this feature, the three-dimensional trajectory model of the arm operation of the construction personnel is established, the trajectory boundary and speed change of the arm movement are accurately captured, and the spatial hierarchical modeling of the sharp structure of the equipment surface is combined to realize dynamic assessment and accurate prediction of the arc risk.

[0111] The unit vector corresponding to the trajectory direction of the arm action of the construction personnel is used to calculate the field control risk in cooperation with the normal vector of the sharp end structure, to guide the active regulation of the arc position by the magnetic field deflection force, and to ensure that the arc is maintained in the predetermined area outside the safe distance of the construction personnel.

[0112] Obtaining the center point of the equipment;

[0113] Performing a spatial hierarchical sharpness modeling strategy, dividing a plurality of concentric spherical layers on the equipment according to the center point, identifying the sharp end based on a set area threshold, and calculating the sharpness of the sharp end;

[0114] The specific implementation combines point cloud processing, spatial clustering, distance calculation and real-time data fusion of the prior art, and specific details can be implemented using an existing open source point cloud processing library (such as PCL) or a self-developed algorithm.

[0115] The embodiment selects a discrete point cloud on the surface of the device, and if an existing open source point cloud processing library (such as PCL) is used, spatial clustering is performed through Euclidean Cluster Extraction or DBSCAN algorithm to separate the point cloud into a tip candidate region; then the normal vector of each region is estimated by a neighborhood method or calculated by PCA, which is used for subsequent tip sharpness evaluation and arc guiding control.

[0116] A plurality of discrete points are selected on the surface of the device, and the coordinates of each discrete point in a three-dimensional coordinate system are obtained;

[0117] The mean value of the x-axis coordinate value, the mean value of the y-axis coordinate value and the mean value of the z-axis coordinate value of each discrete point are calculated as the coordinate values of the center point of the device in the three-dimensional coordinate system;

[0118] A plurality of concentric spherical layers are divided on the device with the center point of the device as the center, and the interval between each concentric spherical layer is a layer interval;

[0119] The discrete points on the surface of the device are intercepted by the concentric spherical layers to form a plurality of spatially separated segment regions;

[0120] The area of each segment region is calculated, specifically:

[0121] The mean value of the coordinates of all discrete points in the segment region on each coordinate axis in the three-dimensional coordinate system is calculated to obtain the coordinate values of the center point of the segment region;

[0122] The Euclidean distance from the center point to each discrete point in the segment region is calculated, and the mean value of all Euclidean distances is calculated, and the result is recorded as ;

[0123] The Euclidean distance from the center point to each discrete point in the segment region is calculated, and the mean value of all Euclidean distances is calculated, and the result is recorded as , wherein is the area of the segment region;

[0124] An area threshold is set;

[0125] The segment region is a tip structure region of the tip structure intercepted by the concentric spherical layer

[0126] The center point of any tip structure region is obtained, and the normal vector of the tip structure region is established;

[0127] The normal vector is determined by the center point of the device and the center point of the tip structure region, and points from the center point of the device to the center point of the tip structure region;

[0128] Normal vector of optional two tip structure regions ;

[0129] Calculate the included angle of normal vectors , wherein, is the dot product of normal vectors, is the length of the normal vector;

[0130] Set the included angle threshold , then the two tip structure regions correspond to the same tip;

[0131] Calculate the sharpness of the tip , wherein, is the total number of tip structure regions corresponding to the tip, the more the total number of tip structure regions corresponding to the tip, the higher the tip, and the smaller the total area of the tip structure region, the sharper the tip;

[0132] Because the situation of generating a whole arc due to equipment failure is not the shape of lightning similar to closing on high-voltage lines, but the range is small, and the arc flame is not high, so concentrating the arc to the tip area can concentrate the dispersed small arcs, and will not form an arc similar to lightning with very high concentration and very strong instability, plus the structure of the device itself can greatly protect the safety of construction personnel, avoid the harm of small arcs to construction personnel in a closed and dark space;

[0133] Get the unit vector corresponding to the trajectory direction of the construction personnel when maintaining the equipment, in this embodiment, the normal vector corresponding to the trajectory direction is the normal vector determined by the connecting line from the starting point to the ending point of the construction personnel movement trajectory region, and the starting point points to the ending point, which is to facilitate modeling the movement behavior of the construction personnel.

[0134] Execute the main arc field control guidance strategy, calculate the field control risk of each tip based on the trajectory boundary and the tip sharpness and the unit vector, and determine the target tip;

[0135] For each tip:

[0136] Get the normal vector of all tip structure regions corresponding to the tip, calculate the average value of the normal vector, and record the average value as the tip structure vector ;

[0137] Get all the unit vectors corresponding to the moving direction of the construction personnel when maintaining the equipment, calculate the average value of the unit vectors, and record the result as the moving vector ;

[0138] Calculate the included angle of the tip structure vector and the moving vector​​​​ , ,in, For dot product, For the module length;

[0139] Obtain the tip structure region furthest from the device center point among all tip structure regions corresponding to the tip, and obtain the center point of the tip structure region, denoted as the tip point;

[0140] Choose any number of boundary points on the trajectory boundary curve one and trajectory boundary curve two;

[0141] Calculate the Euclidean distance between the cusp and each boundary point, and denote the minimum Euclidean distance as . ;

[0142] Normalize the tip sharpness, included angle, and Euclidean distance, and update them to the normalized values;

[0143] Computational cutting-edge field control risks , ,in, These are respectively the sharpness of the tip and the included angle. Euclidean distance The weight, This is to prevent positive numbers with a denominator of 0;

[0144] The tip with the lowest field control risk is designated as the target tip. Based on the target tip and the largest tip structure region, a spatial tubular domain is constructed in which it is located as the predetermined region. The spatial tubular domain is cylindrical in shape, and the area of ​​the bottom surface of the cylinder is the area of ​​the largest tip structure region. In fact, the cylindrical spatial tubular domain wraps the largest tip structure region, concentrating the electric arc in the cylindrical spatial tubular domain.

[0145] When the electric arc is concentrated at the tip of the target to form the main arc, the arc is like a lighter flame and does not rely on a fixed structure, so it is unstable. The smaller the angle, the higher the probability that the arc's vector at the tip of the target will move to the vector of the worker's movement. Moreover, the arc has the ability to extend and may develop in the direction of the worker's movement vector as the worker moves, eventually injuring the worker. Therefore, the smaller the angle, the greater the risk of field control. The sharper the tip, the more concentrated the arc, and the smaller the dispersed tiny arcs, so the lower the risk of field control. The smaller the Euclidean distance between the tip and each boundary point, the more likely it is to affect the worker.

[0146] The existing arc guiding technology focuses more on deflecting the arc away from the operator to reduce the risk of personal injury, often ignoring the influence of the device structure itself, resulting in high actual guiding cost and unsatisfactory effect. For example, the existing arc guiding calculation determines the optimal main arc position on the device structure which is a flat plane, but the structure connected to this plane is a protruding cylindrical structure, and only a slight arc deflection is needed to achieve a more stable main arc. Therefore, the fixed magnetic field layout fails to combine the complex three-dimensional sharp structure of the device surface, making it difficult to achieve effective aggregation and stable control of the arc.

[0147] The present scheme models the three-dimensional concentric spherical layer sharpness of the device and actively guides the arc to the area where the device surface sharpness is prominent. The sharp area converges higher density of arc energy due to its geometric characteristics, enhancing the aggregation of the arc, thereby forming a more stable main arc.

[0148] By combining the real-time trajectory data of the operator, the optimal target tip for arc guiding is dynamically calculated, ensuring that the arc is away from the operator and effectively utilizing the structural advantages of the device itself, reducing the waste of magnetic field energy, reducing the guiding cost, and improving the precision and safety of arc control.

[0149] The field control risk is the probability of failure to maintain the arc within the predetermined area;

[0150] Applying a magnetic field deflection force to the device to maintain the arc within the predetermined area of the target tip is the prior art;

[0151] When the operator is repairing the device:

[0152] An arc deviation safety protection strategy is executed to monitor the distribution and diffusion speed of the arc boundary in real time, and to determine whether the arc has deviated. When the arc deviates and is predicted to pose a danger to the operator, the power is immediately cut off;

[0153] When it is detected that the arc is not maintained in the predetermined area, it is determined that the arc has deviated;

[0154] Optionally, multiple detection points are detected on the arc boundary;

[0155] For any one detection point:

[0156] The diffusion speed of the detection point is monitored in real time , and a power-off test experiment is performed:

[0157] The acceleration of the detection point when the power is cut off is recorded as ;

[0158] The time length when the diffusion speed of the detection point decreases to 0 is calculated , ;

[0159] The diffusion speed of the detection point is calculated from The displacement of the moving point is reduced to 0 , ;

[0160] The displacement of the detection point caused by the residual energy after power-off is obtained , and and are equal in direction;

[0161] After the high-power DC electrical equipment is cut off from the main power supply, the arc will not disappear immediately. The residual amount of electricity stored in the equipment and the conductor will continue to provide energy for the arc, causing the arc boundary to remain diffused and moving for a certain period of time after the power-off moment. During this period, the arc is still dangerous, and if not taken into account, simply judging the arc to disappear based on the power-off moment may underestimate the arc diffusion range, leaving a safety hazard. Especially in a closed space, the arc diffusion caused by the residual amount of electricity may be short but the distance may be large, and the safety of the construction personnel and equipment is still threatened, which must be fully reflected in the safety protection strategy.

[0162] The specific calculation method is to measure the power-off experiment on the actual equipment or experimental device

[0163] Test: Apply an arc caused by a fault and record the power-off moment. Use a high-speed camera or an arc boundary sensor to capture the diffusion trajectory of the arc boundary after power-off. Calculate the distance moved by the arc boundary from the power-off moment to the final stable disappearance, which is recorded as the residual diffusion distance ; The diffusion displacement is not a constant, but is related to the power level of the equipment, the breaking speed, and the severity of the fault.

[0164] Increased equipment power → higher residual energy, corresponding increase in diffusion displacement;

[0165] Greater fault current → more intense energy release, possible increase in diffusion displacement;

[0166] Faster breaking speed (such as vacuum circuit breaker) → lower residual energy, reduced diffusion displacement value;

[0167] Calculate as the diffusion distance of the arc boundary after power-off;

[0168] Calculate the distance moved by the construction personnel within the time period , In this embodiment, the distance moved by the construction personnel refers to the actual displacement distance of the hands of the construction personnel within the predefined trajectory boundary, which is used to accurately reflect the dynamic changes of the risk of contacting the equipment during the construction operation. The overall trajectory of the construction personnel is limited in the trajectory boundary, which is protected by itself, and at this time only the distance of the hands along the moving direction needs to be considered;

[0169] the diffusion displacement of the detection point is mapped to the displacement of the construction worker the diffusion displacement of the detection point is mapped to the displacement of the construction worker the diffusion displacement of the detection point is mapped to the displacement of the construction worker the diffusion displacement of the detection point is mapped to the displacement of the construction worker

[0170] the diffusion displacement of the detection point is mapped to the displacement of the construction worker the diffusion displacement of the detection point is mapped to the displacement of the construction worker the diffusion displacement of the detection point is mapped to the displacement of the construction worker the diffusion displacement of the detection point is mapped to the displacement of the construction worker

[0171] In this embodiment, the diffusion displacement of the detection point is mapped to the displacement of the construction worker Figure 2 the diffusion displacement of the detection point is mapped to the displacement of the construction worker the diffusion displacement of the detection point is mapped to the displacement of the construction worker the diffusion displacement of the detection point is mapped to the displacement of the construction worker

[0172] The displacement is a vector, including the start point and the end point. Since the displacement direction of the detection point varies, the displacement of the detection point is mapped to the displacement of the construction worker The mapping of the vector is prior art. The purpose of the mapping is to unify the quantification of the diffusion of the detection point and the movement of the construction worker to the same direction. At this time represents the closest distance between the detection point and the construction worker in the time length under the opposite movement of the diffusion of the detection point and the movement of the construction worker. If the closest distance is greater than the distance threshold , it indicates that the construction worker may be close to the arc and be injured, and thus immediate power-off is required. The distance threshold here can be adjusted to limit the safety degree of protecting the construction worker.

[0173] The distance threshold is set as

[0174] If , the arc deviation poses a danger to the construction worker, and immediate power-off is required.

[0175] When a whole-body arc occurs in a high-power DC device, immediate power-off is not required because power-off can eliminate the arc but can cause system stability risks and production impacts. Meanwhile, the residual diffusion of the arc after power-off can bring additional dangers. In the face of a whole-body arc device, the construction worker will, under the premise of ensuring his / her safety, take scientific path planning and arc control measures to avoid blind power-off and ensure the continuity and safety of the maintenance work.

[0176] The construction worker can quickly evaluate the on-site safety condition and perform on-site fault diagnosis and maintenance on the whole-body arc device.

[0177] If , the arc offset does not pose a danger to the worker;

[0178] When the arc offset does not pose a danger to the worker:

[0179] An arc dispersion risk prediction strategy is executed to predict the dispersion of the arc in a future time period, and based on the dispersion, safety measures are initiated, including primary arc field control guidance and power-off.

[0180] Obtain the arc intensity at each discrete point on the surface of the device ;

[0181] Calculate the Euclidean distance of each discrete point from the boundary point on the arc boundary, and obtain the minimum distance as the nearest distance of each discrete point from the arc boundary ;

[0182] Calculate , wherein is the dispersion of the arc at the current time;

[0183] Calculate the rate of change of the dispersion , wherein is the change in dispersion in ;

[0184] If the rate of change , the dispersion shows an increasing trend;

[0185] Real-time monitoring of the diffusion acceleration of the detection point on the arc boundary ;

[0186] Calculate the distance of the arc boundary diffusion in the future time period from the current time ; ;

[0187] , calculate the mean distance to obtain ;

[0188] If and , power off immediately, this embodiment satisfies this condition;

[0189] If and , execute primary arc field control guidance;

[0190] If and , execute primary arc field control guidance, which is the previously mentioned application of a magnetic field deflection force to the device to maintain the arc within the predetermined region formed by the target tip;

[0191] If and If the arc is not adjusted, the current situation is maintained, and if the arc is adjusted, it may cause the arc to deviate and pose a danger to the construction personnel, and the purpose of adjusting the arc is to protect the safety of the construction personnel, and no additional action is needed when the construction personnel is already safe.

[0192] The prior art obtains arc boundary and intensity information in real time through high-speed images, infrared imaging, electromagnetic sensing, and electrical parameter measurement, and realizes dynamic identification and statistics of arc diffusion and intensity by combining image processing and signal analysis methods.

[0193] Sensor: IMU glove (accelerometer ± 16g, gyroscope ± 2000° / s);

[0194] Camera: high-frame-rate RGB-D camera inside the cabinet (30 fps, accuracy ± 1 cm);

[0195] Installation position: IMU glove on the back of the hand, camera arranged on the top and front inner wall of the cabinet;

[0196] Fusion algorithm: synchronize IMU and camera data based on timestamps;

[0197] Coordinate system: right-handed three-dimensional coordinate system;

[0198] Data fusion: existing technology weighted Kalman filter is used to calculate high-precision trajectory points;

[0199] Sampling frequency: IMU 100 Hz, camera 30 Hz, fused trajectory point output frequency 30 Hz;

[0200] The construction personnel does not immediately power off when approaching the equipment or when there is an initial fault, in order to avoid affecting the construction progress and equipment operation stability due to premature power-off. Only when the system confirms that the arc poses an actual threat to personnel through real-time monitoring and risk assessment, the power-off protection is started, realizing the best balance between safety and efficiency.

[0201] It should be noted that, in the present document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0202] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, several improvements and refinements can be made without departing from the technical principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method of detecting a high-power DC appliance, characterized by, The application relates to a method for guiding a high-power direct-current electric device, and belongs to the technical field of electric device safety. When a high-power direct-current electric device fails and generates a body arc, a magnetic field deflection force is applied to the device to maintain the arc in a predetermined area, specifically: A three-dimensional coordinate system is established in the space where the device is located; The trajectory boundary and trajectory speed of the construction personnel when repairing the device are calculated based on the three-dimensional coordinate system; The center point of the device is obtained; A spatial hierarchical sharpness modeling strategy is executed, a plurality of concentric spherical layers are divided on the device based on the center point, a sharp end is identified based on a set area threshold, and the sharpness of the sharp end is calculated, including: A plurality of discrete points are selected on the surface of the device, and the coordinates of each discrete point in the three-dimensional coordinate system are obtained; The mean value of the x-axis coordinate value, the mean value of the y-axis coordinate value, and the mean value of the z-axis coordinate value of each discrete point are calculated as the coordinate values of the center point of the device in the three-dimensional coordinate system; A plurality of concentric spherical layers are divided on the device with the center point of the device as the center, and the interval between each concentric spherical layer is the layering interval; The discrete points on the surface of the device are intercepted by the concentric spherical layers to form a plurality of spatially separated segment areas; The area of each segment area is calculated, specifically: The mean value of each coordinate axis coordinate of all discrete points in the segment area in the three-dimensional coordinate system is calculated to obtain the coordinate value of the center point of the segment area; The Euclidean distance from the segment region center point to each discrete point on the segment region is calculated, and the mean of all Euclidean distances is calculated, and the result is recorded as ; Computing wherein, is the area of the segment region; Setting an area threshold ; If , the segment region is a tip structure region of the concentric sphere layer intercepted by the tip structure region of the structure where the tip is located; The center point of any sharp end structure area is obtained, and the normal vector of the sharp end structure area is established; The normal vector is determined by the center point of the device and the center point of the sharp end structure area, and points from the center point of the device to the center point of the sharp end structure area; Normal vector of the optional two tip structure regions and ; Computing the angle between two vectors , where, is the dot product of the normal vectors, is the length of the normal vectors; Setting an angle threshold , if , the two tip structure regions correspond to the same tip; Sharpness of a computing tip , wherein, is the total number of tip corresponding tip structure areas; The unit vector corresponding to the trajectory direction of the construction personnel when repairing the device is obtained; A main arc field control guidance strategy is executed, the field control risk of each sharp end is calculated based on the trajectory boundary, the sharpness of the sharp end, and the unit vector, and a target sharp end is determined, including: For each sharp end: obtaining normal vectors of all tip structure regions corresponding to the tip, calculating an average value of the normal vectors, and recording the average value as a tip structure vector ; Obtain the unit vector corresponding to the moving direction when all the construction personnel maintain the equipment, calculate the mean value of the unit vector, and record the result as the moving vector ; Computing the angle between the tip structure vector and the movement vector , wherein, is the dot product, is the module length; Obtain the sharp end structure area farthest from the center point of the device among all sharp end structure areas corresponding to the sharp end, and obtain the center point of the sharp end structure area, denoted as the sharp point; A plurality of boundary points are selected on the trajectory boundary curve one and the trajectory boundary curve two of the trajectory boundary; The Euclidean distance of the cusp point and each boundary point is calculated, and the minimum Euclidean distance is recorded as ; The sharpness of the sharp end, the included angle, and the Euclidean distance are normalized and updated to normalized numerical values; Field control risk of computing tip , wherein, are weights of tip sharpness, included angle and Euclidean distance respectively, is a positive number for preventing denominator from being 0; The sharp end with the lowest field control risk is recorded as the target sharp end, and the sharp end structure area with the largest area corresponding to the target sharp end is taken as the reference to construct a spatial tubular domain where the target sharp end is located as the predetermined area; The field control risk is the probability of failure in maintaining the arc in the predetermined area; A magnetic field deflection force is applied to the device to maintain the arc in the predetermined area formed by the target sharp end; When the construction personnel repair the device: An arc offset safety protection strategy is executed to monitor the distribution and diffusion speed of the arc boundary in real time, and to determine whether the arc is offset. When the arc is offset and it is predicted that the construction personnel will be in danger, the power supply is immediately cut off; When the arc is offset and the construction personnel is not in danger: An arc dispersion risk prediction strategy is executed to predict the dispersion of the arc in the future period, and to start safety measures based on the dispersion, including the main arc field control guidance and power cut-off.

2. The high-power DC appliance detection method of claim 1, wherein, The calculation of the trajectory boundary and the trajectory speed of the construction personnel when repairing the device based on the three-dimensional coordinate system includes: A coordinate axis in the three-dimensional coordinate system is selected as a reference axis, a plurality of equidistant parallel lines are divided on the surface of the device in a direction perpendicular to the reference axis, For any construction personnel, the moving track area of the construction personnel when repairing the equipment is collected, and the moving track area intersects with each parallel line to obtain two intersection points on each parallel line; The two intersection points on the outermost side of each parallel line are named as boundary point one and boundary point two respectively; Connecting all the boundary points one on the parallel lines forms a track boundary curve one, and connecting all the boundary points two on the parallel lines forms a track boundary curve two; The track boundary curve one and the track boundary curve two on the surface of the equipment are taken as the track boundary of the construction personnel when repairing the equipment; Record the time length of each construction personnel moving along the moving track area, and calculate the mean value of the time length to obtain t; obtain the number of parallel lines And the distance between adjacent parallel lines ; Calculating a construction worker's trajectory speed : .

3. The high-power DC appliance detection method of claim 2, wherein, The execution of the electric arc offset safety protection strategy, real-time monitoring of the distribution and diffusion speed of the electric arc boundary, judgment of whether the electric arc is offset, when the electric arc is offset and it is predicted that the construction personnel is in danger, power off immediately, including: When it is detected that the electric arc is not maintained in the predetermined area, it is determined that the electric arc is offset; On the electric arc boundary, a plurality of detection points are selected, and for any one detection point: Real-time monitoring of diffusion rates at detection points Performing a power-off test experiment: The acceleration of the detection point at the time of power-off is recorded as ; a length of time for which the diffusion velocity of the detection point decreases to zero , ; The diffusion velocity of the detection point is calculated from the displacement of the travel , ; Acquiring the residual power after power-off causes the displacement of the detection point to spread , and and the directions of which are equal Calculations Diffusion displacement as a detection point after power-off; Computing duration Displacement of the internal construction worker movement , ; Diffusion displacement of detection points Mapping to displacement of construction worker Obtaining displacement of construction worker Mapping displacement parallel to direction acquiring the displacement of the end position and mapping the displacement of the end position, and acquiring the distance of the two end positions, recording the smallest distance as ; Setting a distance threshold ; If then the arc offset is dangerous to the operator and the power is immediately disconnected. If then the arc drift does not pose a danger to the operator.

4. The high-power DC appliance detection method of claim 3, wherein, The execution of the electric arc dispersion risk prediction strategy, prediction of the dispersion of the electric arc in the future period, and based on the dispersion, the safety measures are started, including: Acquiring electrical arc intensity at each discrete point of a surface of a device ; calculating the Euclidean distance of each discrete point from the boundary points on the arc boundary and taking the minimum distance as the nearest neighbor distance of each discrete point from the arc boundary ; Computing wherein, is the dispersion of the arc at the current time instant; The rate of change of the dispersion is calculated wherein, is the change in dispersion over the length of time t. If the rate of change then the dispersion shows an increasing trend; If the rate of change then the dispersion shows a weakening trend.

5. The high-power DC appliance detection method of claim 4, wherein, The execution of the electric arc dispersion risk prediction strategy, prediction of the dispersion of the electric arc in the future period, and based on the dispersion, the safety measures are started, including: The execution of the electric arc dispersion risk prediction strategy, prediction of the dispersion of the electric arc in the future period, and based on the dispersion, the safety measures are started, including: Real-time monitoring of diffusion acceleration of detection points on arc boundary ; The distance of the point spread is detected over a future time period of a duration from the current time instant The distance of the point spread is detected over a future time period of a duration from the current time instant The distance of the point spread is detected over a future time period of a duration , the mean value of the distances is calculated to obtain ; If and then power off immediately; If and then execute main arc field controlled guidance; If and then execute main arc field controlled guidance; If and then the status quo is maintained.

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