Dynamic simulation method for hinge wear fault of operating mechanism of electrically-driven high-voltage circuit breaker

Abstract

The invention relates to an electrically-driven high-voltage circuit breaker operating mechanism hinge wear fault dynamics simulation method, and belongs to the technical field of high-voltage circuit breaker fault diagnosis, and the method comprises the following steps: S1, building a high-voltage circuit breaker kinematics model based on servo motor driving; s2, an initial state is determined, and hinge gap stress is calculated; s3, a servo motor is started, and coordinates of all points at the current moment are calculated according to the stress conditions of the crank arm, the transmission connecting rod and the open range stage / overtravel stage and a kinematical equation of a servo motor operating mechanism; s4, updating r1 and r2 according to the coordinates of each point at the current moment, calculating delta 1 and delta 2, and calculating the contact force and friction force of the hinge gap to obtain the stress condition at the next moment; s5, repeating the steps S3-S4, and carrying out iteration to obtain the stress and movement conditions of the circuit breaker which is directly driven and operated by the motor at each moment; and S6, the change condition of the collision angle of the hinged shaft and the reaming hole in one movement period is analyzed, and a gap value after the abrasion fault is established.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-voltage circuit breaker fault diagnosis, and relates to a method for simulating wear failure of hinges of an operating mechanism of an electric-driven high-voltage circuit breaker, Background Art

[0002] High-voltage circuit breakers use motor-driven operating mechanisms. Compared with traditional spring, electromagnetic, and hydraulic operating mechanisms, they have fewer parts and simpler structures. In addition, they can rely on the motor control system to adjust the output of the operating mechanism to match the load during the opening and closing process. They have higher reliability and intelligence, and are an important development direction for high-voltage circuit breakers that adapt to new power systems. High-voltage circuit breakers are the only control and protection equipment in the primary equipment of the power system. They are important control equipment for connecting and disconnecting circuits, cutting off and isolating faults. If a fault occurs, it will cause great harm to the power grid. The short-term load during the opening and closing process of high-voltage circuit breakers is large, often accompanied by severe transient shocks, which can easily cause wear at the hinge joints of the operating mechanism rods. The hinge wear fault of the servo-driven high-voltage circuit breaker operating mechanism is difficult to simulate and diagnose. Therefore, it is crucial to invent a hinge wear state simulation method for circuit breaker fault analysis and early diagnosis research.

[0003] Currently, the fault status data of most circuit breakers are obtained through simulated fault experiments. Although this method is more realistic and reliable in obtaining fault data, the cost of setting up the experimental platform is high, the process is cumbersome, the sample data is insufficient, and most of the experiments are fault manifestations such as loose frame bolts and mechanism jamming. It is difficult to simulate and explore the fault mechanism caused by hinge wear defects, and there is a lack of modeling and analysis of such faults in circuit breakers.

[0004] In summary, the short-term load of high-voltage circuit breakers during the opening and closing process is large, often accompanied by severe transient impacts, which can easily lead to wear failures at the hinge joints of the rods. The data used for existing circuit breaker fault diagnosis comes from experimental tests, which is costly and the fault simulation is constrained by space, resulting in a small amount of sample data; and the hinge wear failure of the servo-driven high-voltage circuit breaker operating mechanism is difficult to simulate and diagnose. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a dynamic simulation method for the hinge wear fault of the operating mechanism of an electrically driven high-voltage circuit breaker. By establishing a fault model of the hinge wear state of the circuit breaker through a dynamic model, simulation model data can be obtained to solve the problems of high experimental cost and insufficient sample size. In addition, the establishment of the fault model is more conducive to the analysis of the fault mechanism.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for dynamic simulation of hinge wear failure of an operating mechanism of an electric-driven high-voltage circuit breaker comprises the following steps:

[0008] S1: Establish kinematic model of high voltage circuit breaker based on servo motor drive;

[0009] S2: Determine the initial state and calculate the hinge gap force in the initial state;

[0010] S3: Start the servo motor, and calculate the coordinates of each point at the current moment according to the force conditions of the crank arm, the transmission connecting rod, the force conditions in the opening stage and the overtravel stage, and the kinematic equation of the servo motor operating mechanism;

[0011] S4: Update r according to the coordinates of each point at the current moment 1 With r 2 , where r 1 is the clearance vector from the hinge axis center point B at the hinge connection between the crank arm and the transmission connecting rod to the reaming hole center point B′, r 2 is the clearance vector from the hinge axis center point C′ to the reaming hole center point C at the hinge connection between the transmission connecting rod and the insulating pull rod; calculate δ 1 With δ 2 , where δ 1 is the clearance collision vector at the hinge connection between the crank arm and the transmission link, δ 2 is the gap collision vector at the hinge connection between the transmission connecting rod and the insulating pull rod; and the hinge gap contact force and friction force are calculated to obtain the force condition at the next moment;

[0012] S5: repeat steps S3-S4, iteratively obtain the force and motion conditions of the circuit breaker directly driven by the motor at each moment;

[0013] S6: Analyze the change of the collision angle between the hinge shaft and the reaming hole in a motion cycle of the hinge, and establish the clearance value after wear failure based on the change distribution of the collision angle.

[0014] Furthermore, the kinematic model of the high-voltage circuit breaker driven by the servo motor is as follows:

[0015] Let AB be the crank arm, B′C′ be the transmission connecting rod, points B and B′ are the hinge axis and the center of the reaming hole of the hinge between the crank arm and the transmission connecting rod respectively, C is the bottom of the insulating pull rod, points C′ and C are the hinge axis and the center of the reaming hole of the hinge between the transmission connecting rod and the insulating pull rod respectively;

[0016] The coordinate relationship of each point is as shown in formula (1). By taking the first and second order derivatives of the coordinates, the velocity and acceleration of translational motion along the x-axis and y-axis can be obtained;

[0017]

[0018] θ 1 is the angle between the crank arm and the horizontal line, and its value is consistent with the motor rotor position angle; θ c1is the clearance vector angle at the hinge connection between the crank arm and the transmission connecting rod, θ 2 is the angle between the transmission link B′C′ and the positive direction of the x-axis, θ c2 is the gap vector angle at the hinge connection between the transmission connecting rod and the insulating pull rod.

[0019] Furthermore, in the initial state, θ 1 is the initial angle of the motor rotor, which is determined by the opening distance and overtravel of the circuit breaker during opening and closing; B coincides with B′, C′ coincides with C, r 1 With r 2 are all 0, and the position of each point is calculated by formula (1); and δ 1 With δ 2 It is known that the hinge gap force can be calculated.

[0020] Further, the stress condition of the hinge gap is described as follows:

[0021] (a) Ideally, the hinge axis is aligned with the center of the reaming hole, and C is the clearance value;

[0022] (b) When the hinge axis moves in the reaming hole but does not move with the reaming hole, the clearance vector is from the hinge axis point P to the reaming hole point P′. Gap Collision Vector The calculation is shown in formula (2):

[0023]

[0024] At this time, the position relationship between the shaft and the reaming hole and In the opposite direction, there is no interaction force between the hinge shaft and the reaming hole;

[0025] (c) When the hinge shaft collides with the reaming hole, and In the same direction, the hinge axis is subjected to a normal contact force F n The tangential friction force F t , and at the same time the reaming is subjected to a reaction force.

[0026] Furthermore, the normal contact force F N The calculation adopts the LN nonlinear spring damping model considering hysteresis damping, as shown in formula (3):

[0027]

[0028] K is the contact stiffness coefficient of the material; the index n is 1.5 for metal contact; c e is the material recovery coefficient, which is determined according to the energy loss; is the initial collision velocity between the hinge shaft and the reaming hole; is the collision velocity between the hinge shaft and the reaming hole, is the clearance collision vector The derivative with respect to time t;

[0029] Tangential friction force F t The modified Coulomb friction model is used, in which the friction coefficient is related to the tangential sliding velocity v t As shown in formula (4):

[0030]

[0031] v s is the critical speed of static friction; v d is the critical speed of maximum dynamic friction; μ s is the static friction coefficient; μ d is the sliding friction coefficient; sign(v t ) is a symbolic function;

[0032] F t The calculation formula is shown in formula (5):

[0033] F t =-μ(v t )F N (5).

[0034] Furthermore, in step S3, the arm force equation is as shown in formula (6):

[0035]

[0036] Among them, F RAx 、F Ray are the components of the reaction force of the transmission shaft on the crank arm on the x-axis and y-axis, respectively, n1 、F t1 are the hinge gap contact force and friction force on point B respectively;

[0037] Load torque T calculated on the motor shaft L As shown in formula (7), the direction is clockwise:

[0038]

[0039] The force equation of the transmission connecting rod is shown in formula (8):

[0040]

[0041] Among them G 2 is the weight of the transmission connecting rod, F n2 、F t2 are the hinge gap contact force and friction force on point C′ respectively;

[0042] In the opening stage, the insulating pull rod and the moving contact are regarded as a whole, and the motion force equation is shown in formula (9):

[0043] Among them, F close is the arc extinguishing chamber self-closing force, F e is the electrokinetic repulsion, G 3 , G 4 , G spr are the gravity of the insulating pull rod, the moving contact, and the overtravel spring, respectively. N is the pressure of the arc extinguishing chamber wall at point C, f C is the friction force on point C;

[0044] In the overtravel stage, the insulating pull rod and the moving contact are discussed separately. Assuming that the spring is uniformly extended, the force equation is shown in formula (10):

[0045]

[0046] Among them, F spr is the overtravel spring force, F n3 is the collision contact force between the moving and static contacts;

[0047] The kinematic equation of the servo motor actuator is shown in formula (11):

[0048]

[0049] u d 、u q are the stator voltages of the d-axis and q-axis respectively, i d 、i q are the stator currents of the d-axis and q-axis respectively, L d , L q are the components of the stator inductance on the d-axis and q-axis, ω e is the motor electrical angular velocity, ψ f is the permanent magnet flux of the motor, ω m is the motor mechanical angular velocity, J is the motor rotor and load moment of inertia, B is the friction factor, T L With T f are load torque and friction torque respectively;

[0050] According to the force conditions and equations (6) to (11), the accelerations of points B, B′, C′, C, and D are obtained, the velocities are obtained by integration, and the coordinate values ​​of B, B′, C′, C, and D are obtained by further integration.

[0051] Further, in step S4, r is updated according to the coordinates of each point at the current moment. 1 With r 2 , and then use formula (2) to find δ 1 With δ 2 , and calculate the hinge gap contact force and friction force according to equations (3) to (5) to obtain the force condition at the next moment.

[0052] Further, step S5 specifically includes the following steps:

[0053] Assume that the angle between the hinge shaft and the reaming hole is θ c , which is called the contact angle, and its value range is [-π,π]; the clearance value C is a constant, and the clearance value after hinge wear changes with the contact angle θ c The function C(θ c ), which is defined as shown in formula (12):

[0054] C(θ c )=C o [k c P(θ c )+1] (12)

[0055] In formula (12), C o is the clearance value of the hinge in the initial healthy state; k c is the hinge wear coefficient, k c ≥0, and k c The larger the wear, the more serious the wear; P(θ c ) is the contact angle θ c The probability of; Assume that the total number of samples of contact angles in a closing and opening cycle is N, and θ c Divided into n intervals, falling within the interval The sample size on is N m , then P(θ c ) is calculated as shown in formula (13):

[0056]

[0057] First, the dynamic model with gap is established to simulate the hinge gap contact collision under the opening and closing movement of the motor-driven circuit breaker, and the distribution of different contact angles is sought. The probability formula of different contact angles is established according to formula (13), so as to obtain the gap function C(θ c ), through C(θ c ) replaces the gap value C to obtain the hinge failure dynamics simulation taking into account the actual wear conditions.

[0058] The beneficial effects of the present invention are:

[0059] (1) A dynamic model of high-voltage circuit breaker opening and closing driven by a servo motor with hinge gap was established to simulate the dynamic characteristics under different hinge wear degrees;

[0060] (2) In the actual opening and closing process, the collision contact angle between the hinge shaft and the reaming hole inside the hinge is not uniformly distributed. Therefore, simply increasing the gap value cannot accurately simulate the hinge wear failure. The present invention proposes a gap function C(θ c ), which can better reflect the gap characteristics of the hinge after actual wear;

[0061] (3) The gap function C(θ c ) is brought into the dynamic model simulation with gap, and the motion characteristics of the high-voltage circuit breaker driven by servo motor under different hinge wear fault degrees as well as the speed and current of the motor can be obtained, which is convenient for studying the fault characteristics and mechanism and also provides data support for fault diagnosis.

[0062] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0064] Figure 1 The structure diagram of the high voltage circuit breaker based on servo motor drive;

[0065] Figure 2 It is the hinge structure diagram;

[0066] Figure 3 is the kinematic model of the circuit breaker with gap;

[0067] Figure 4 The force condition of the hinge gap, where (a) is the hinge shaft aligned with the center of the reaming hole, (b) is the hinge shaft not contacting the reaming hole, and (c) is the hinge shaft colliding with the reaming hole;

[0068] Figure 5 is the force condition of the crank arm;

[0069] Figure 6 is the force condition of the transmission connecting rod;

[0070] Figure 7 The force conditions of the transmission connecting rod and the moving contact in the opening stage;

[0071] Figure 8 The force conditions of the transmission connecting rod (a) and the moving contact (b) in the overtravel stage;

[0072] Fig. 9 is the probability distribution P(θ) of the contact angle of the hinge of the arm during the opening process of a circuit breaker c );

[0073] Fig.10 is the hinge clearance C(θ c );

[0074] Fig.11 The travel of the moving contact before and after the wear of the crank arm hinge;

[0075] Fig.12 The speed of the moving contact before and after the arm hinge is worn;

[0076] Fig.13 The motor output torque before and after the crank arm hinge is worn;

[0077] Fig.14 It is the motor phase current before and after the arm hinge is worn. DETAILED DESCRIPTION

[0078] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0079] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0080] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0081] The structure of high voltage circuit breaker based on servo motor drive is as follows Figure 1As shown, the servo motor rotor is connected to the circuit breaker body through a transmission shaft, and the servo motor output torque drives the circuit breaker to move. The circuit breaker body is mainly a moving part composed of a crank arm, a transmission connecting rod, an insulating pull rod and other rods connected by hinges. The rotation of the crank arm drives the transmission connecting rod to move, thereby driving the insulating pull rod to move vertically, and finally drives the overtravel spring and the moving contact to move.

[0082] Hinge structure such as Figure 2 As shown, it consists of a hinge shaft and a reaming hole. The hinge shaft is usually fixed in the reaming hole and transmits force to the two connected rods. There is always a gap between the hinge shaft and the reaming hole. The gap value is very small under normal circumstances, but it will increase as the hinge wears. P and P' are the centers of the hinge shaft and the reaming hole respectively.

[0083] Figure 1 The kinematic model of the circuit breaker is as follows: Figure 3 As shown, AB is the crank arm, B′C′ is the transmission connecting rod, and points B and B′ are the hinge axis and the center of the reaming hole of the hinge between the crank arm and the transmission connecting rod respectively, and C is the bottom of the insulating pull rod, and points C′ and C are the hinge axis and the center of the reaming hole of the hinge between the transmission connecting rod and the insulating pull rod respectively.

[0084] The coordinate relationship of each point is as shown in formula (1). By taking the first-order and second-order derivatives of the coordinates, the velocity and acceleration of the translational motion along the x-axis and y-axis can be obtained.

[0085]

[0086] where r 1 is the clearance vector from the hinge axis center point B at the hinge connection between the crank arm and the transmission connecting rod to the reaming hole center point B′; θ c1 is the clearance vector angle at the hinge connection between the crank arm and the transmission connecting rod, θ 2 is the angle between the transmission link B′C′ and the positive direction of the x-axis, θ c2 is the gap vector angle at the hinge connection between the transmission link and the insulating pull rod. The force condition of the hinge gap is described as follows: Figure 4 As shown in the figure, (a) is the ideal case where the hinge axis is aligned with the center of the reaming hole, and C is the clearance value; (b) is the case where the hinge axis moves in the reaming hole but does not move with the reaming hole, and the clearance vector from point P to point P′ is Gap Collision Vector The calculation method is shown in formula (2): Figure 4 As shown, it is the gap vector Subtract the clearance value. It can be seen that the positional relationship between the hinge shaft and the reaming hole shown in (b) and In the opposite direction, there is no interaction force between the hinge shaft and the reaming hole; (c) is when the hinge shaft collides with the reaming hole. and In the same direction, the hinge axis is subjected to a normal contact force Fn The tangential friction force F t , and at the same time the reaming is subjected to a reaction force.

[0087]

[0088] Normal contact force F n The calculation adopts the LN nonlinear spring damping model considering hysteresis damping, as shown in formula (3). K is the contact stiffness coefficient of the material; the index n is generally taken as 1.5 for metal contact; c e is the material recovery coefficient, which is determined according to the energy loss;

[0089] is the initial collision velocity between the hinge shaft and the reaming hole, is the collision velocity between the hinge shaft and the reaming hole, and the clearance collision vector The derivative with respect to time t.

[0090]

[0091] Tangential friction force F t Using the modified Coulomb friction model, the friction coefficient is not a constant, but is related to the tangential sliding velocity v t As shown in formula (4). s is the critical speed of static friction; v d is the critical speed of maximum dynamic friction; μ s is the static friction coefficient; μ d is the sliding friction coefficient; sign(v t ) is the sign function. t The calculation formula is shown in formula (5).

[0092]

[0093] F t =-μ(v t )F N (5)

[0094] The force on the crank arm is as follows Figure 5 As shown, 1 is the length of the crank arm, S 1 is the center of mass of the crank arm, p 1 θ is the distance from the center of mass of the crank to the end point. 1 G is the angle between the crank arm and the horizontal line, and its value is consistent with the motor rotor position angle. 1 is the weight of the crank, F RA 、F RAx 、F Ray are the reaction force of the transmission shaft on the crank arm and its components on the x-axis and y-axis, V Bn 、V Btare the normal velocity and tangential velocity at point B, respectively, and F n1 、F t1 are the hinge gap contact force and friction force at point B respectively.

[0095] Figure 5 The force equation is shown in formula (6).

[0096]

[0097] Load torque T calculated on the motor shaft L As shown in formula (7), the direction is clockwise.

[0098]

[0099] The force of the transmission connecting rod is as follows Figure 6 As shown, 2 is the length of the transmission connecting rod, S 2 is the mass center of the transmission connecting rod, p 2 G is the distance from the center of mass of the crank arm to the end point, 2 is the weight of the transmission connecting rod, V C′n 、V C′t are the normal velocity and tangential velocity of point C′, F n2 、F t2 are the hinge gap contact force and friction force at point C′ respectively.

[0100] Figure 6 The force equation is shown in formula (8).

[0101]

[0102] During the opening stage, the insulating pull rod and the moving contact are considered as a whole, and the force on their movement is as follows: Figure 7 As shown. close is the arc extinguishing chamber self-closing force, F e is the electrokinetic repulsion, G 3 , G 4 , G spr are the gravity of the insulating pull rod, the moving contact, and the overtravel spring, respectively. N is the pressure of the arc extinguishing chamber wall at point C, f C is the friction force at point C.

[0103] Figure 7 The force equation is shown in formula (9).

[0104] During the overtravel stage, the insulating pull rod and the moving contact are discussed separately. The stress conditions are as follows Figure 8 As shown in (a) and (b). spr is the overtravel spring force, F n3 It is the collision contact force between the moving and static contacts.

[0105] Assuming the spring stretches uniformly, Figure 8 The force equation is shown in formula (10).

[0106]

[0107] The kinematic equation of the servo motor actuator is shown in equation (11), u d 、u q are the stator voltages of the d-axis and q-axis respectively, i d 、i q are the stator currents of the d-axis and q-axis respectively, L d , L q are the components of the stator inductance on the d-axis and q-axis, ω e is the motor electrical angular velocity, ψ f is the permanent magnet flux of the motor, ω m is the motor mechanical angular velocity, J is the motor rotor and load moment of inertia, B is the friction factor, T L With T f are load torque and friction torque respectively.

[0108]

[0109] The calculation steps of the dynamic model of the motor-driven high-voltage circuit breaker considering the hinge gap are as follows:

[0110] ①Determine the initial state: θ 1 is the initial angle of the motor rotor, which is determined by the opening distance and overtravel of the circuit breaker during opening and closing; B coincides with B′, C′ coincides with C, r 1 With r 2 are all 0. According to formula (1), the position of each point can be obtained, where r 1 is the clearance vector from the hinge axis center point B at the hinge connection between the crank arm and the transmission connecting rod to the reaming hole center point B′, r 2 is the clearance vector from the hinge axis center point C′ to the reaming hole center point C at the hinge connection between the transmission connecting rod and the insulating pull rod. And δ 1 With δ 2 Knowing that, the hinge gap force can be obtained. The hinge gap force can be divided into the normal contact force F N The tangential friction force F t , can be obtained through equations (3)-(5); where δ 1 is the clearance collision vector at the hinge connection between the crank arm and the transmission link, δ 2 is the clearance collision vector at the hinge connection between the transmission link and the insulating rod

[0111] ② According to the force conditions and equations (6) to (11), the acceleration of points B, B′, C′, C, and D can be calculated. The velocity can be obtained by integration, and the coordinate value can be obtained by further integration.

[0112] ③ Update r according to the coordinates of B, B′, C′, and C at this moment 1 With r 2 , we can find δ by formula (2) 1 With δ 2 , and calculate the hinge gap contact force and friction force according to equations (3) to (5) to obtain the force condition at the next moment;

[0113] Repeat steps ② and ③ to iteratively obtain the force and motion conditions of the circuit breaker directly driven by the motor at each moment.

[0114] Considering the hinge wear caused by the opening and closing movement of the circuit breaker, the hinge gap will increase. And due to the limited angular movement of the circuit breaker arm, the wear at the hinge is often not evenly distributed, but concentrated at certain angles. Therefore, it is necessary to analyze the change of the collision angle between the hinge shaft and the reaming hole in a hinge movement cycle through the circuit breaker dynamics model, and establish the gap value after wear failure according to the change distribution of the collision angle. Assume that the angle when the hinge shaft contacts the reaming hole is θ c , which is called the contact angle, and its value range is [-π,π]. Usually the clearance value C is a constant, and the clearance value after hinge wear changes with the contact angle θ c The function C(θ c ), which is defined as shown in formula (12).

[0115] C(θ c )=C o [k c P(θ c )+1] (12)

[0116] In formula (12), C o is the clearance value of the hinge in the initial healthy state; k c is the hinge wear coefficient, k c ≥0, and k c The larger the wear, the more serious the wear; P(θ c ) is the contact angle θ c Assume that the total number of samples of contact angles in a closing and opening cycle is N, and θ c Divided into n intervals, falling within the interval The sample size on is N m , then P(θ c ) is calculated as shown in formula (13).

[0117]

[0118] First, the dynamic model with gap is established to simulate the hinge gap contact collision under the opening and closing movement of the motor-driven circuit breaker, and the distribution of different contact angles is sought. The probability formula of different contact angles is established according to formula (13), so as to obtain the gap function C(θ c ), through C(θ c ) instead of the clearance value C, the hinge failure dynamics simulation considering the actual wear conditions can be obtained.

[0119] To verify the effect, the initial value of the hinge gap at the turning arm of the high-voltage circuit breaker operating mechanism driven by the servo motor is set to 0.01 mm. According to the established dynamic model simulation, the probability distribution P(θ c ),like Fig. 9 As shown in the figure, it can be seen that the collision angle of the hinge during the opening process is mainly concentrated in -1.6~-0.8rad, so the hinge wear in this range is more serious. The clearance function C(θ c )like Fig.10 As shown, it can be seen that since the hinge wear is mainly concentrated at certain angles, the clearance values ​​at these angles are significantly larger than the clearance values ​​at other angles with lower wear probability.

[0120] The moving contact formation, moving contact displacement, servo motor output torque, motor phase current before and after the arm hinge wears out. Figure 11-14 As shown. It can be seen that after wear, due to the increase in the gap, the total displacement of the moving contact increases, and the oscillation of the moving contact is more serious. There is also an obvious rebound phenomenon during the movement of the moving contact. After wear, the opening speed of the moving contact also decreases. After the arm hinge is worn, the output torque and phase current of the motor increase. The hinge wear state simulation fault model containing the hinge gap based on the present invention can well obtain the moving contact stroke information and the electrical information of the motor operating mechanism.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for dynamic simulation of hinge wear failure of an operating mechanism of an electrically driven high-voltage circuit breaker, characterized in that: The following steps are involved: S1: Establish kinematic model of high voltage circuit breaker based on servo motor drive; S2: Determine the initial state and calculate the hinge gap force in the initial state; S3: Start the servo motor, and calculate the coordinates of each point at the current moment according to the force conditions of the crank arm, the transmission connecting rod, the force conditions in the opening stage and the overtravel stage, and the kinematic equation of the servo motor operating mechanism; S4: Update r1 and r2 according to the coordinates of each point at the current moment, where r1 is the gap vector from the hinge axis center point B at the hinge connection between the crank arm and the transmission link to the center point B' of the reaming hole, and r2 is the gap vector from the hinge axis center point C' at the hinge connection between the transmission link and the insulating pull rod to the center point C of the reaming hole; calculate δ1 and δ2, where δ1 is the gap collision vector at the hinge connection between the crank arm and the transmission link, and δ2 is the gap collision vector at the hinge connection between the transmission link and the insulating pull rod; and calculate the hinge gap contact force and friction force to obtain the force condition at the next moment; S5: repeat steps S3-S4, iteratively obtain the force and motion conditions of the circuit breaker directly driven by the motor at each moment; S6: Analyze the change of the collision angle between the hinge shaft and the reaming hole in a motion cycle of the hinge, and establish the clearance value after wear failure based on the change distribution of the collision angle.

2. The method for dynamic simulation of hinge wear failure of an operating mechanism of an electrically driven high-voltage circuit breaker according to claim 1 is characterized in that: The kinematic model of the high-voltage circuit breaker based on servo motor drive is as follows: Let AB be the crank arm, B′C′ be the transmission connecting rod, points B and B′ are the hinge axis and the center of the reaming hole of the hinge between the crank arm and the transmission connecting rod respectively, C is the bottom of the insulating pull rod, points C′ and C are the hinge axis and the center of the reaming hole of the hinge between the transmission connecting rod and the insulating pull rod respectively; The coordinate relationship of each point is as shown in formula (1). By taking the first and second order derivatives of the coordinates, the velocity and acceleration of translational motion along the x-axis and y-axis can be obtained; θ1 is the angle between the crank arm and the horizontal line, and its value is consistent with the motor rotor position angle; θ c1 is the clearance vector angle of the hinge connection between the crank arm and the transmission link, θ2 is the angle between the transmission link B′C′ and the positive direction of the x-axis, θ c2 is the gap vector angle at the hinge connection between the transmission connecting rod and the insulating pull rod.

3. The method for dynamic simulation of hinge wear failure of an operating mechanism of an electrically driven high-voltage circuit breaker according to claim 2 is characterized in that: In the initial state, θ1 is the initial angle of the motor rotor, which is determined by the opening distance and overtravel of the circuit breaker during opening and closing; B coincides with B′, C′ coincides with C, r1 and r2 are both 0, and the position of each point is calculated by formula (1); and δ1 and δ2 are known, so the hinge gap force can be calculated.

4. The method for dynamic simulation of hinge wear failure of an operating mechanism of an electrically driven high-voltage circuit breaker according to claim 3 is characterized in that: The stress condition of the hinge gap is described as follows: (a) Ideally, the hinge axis is aligned with the center of the reaming hole, and C is the clearance value; (b) When the hinge axis moves in the reaming hole but does not move with the reaming hole, the clearance vector is from the hinge axis point P to the reaming hole point P′. Gap Collision Vector The calculation is shown in formula (2): At this time, the position relationship between the shaft and the reaming hole and In the opposite direction, there is no interaction force between the hinge shaft and the reaming hole; (c) When the hinge shaft collides with the reaming hole, and In the same direction, the hinge axis is subjected to a normal contact force F n The tangential friction force F t , and at the same time the reaming is subjected to a reaction force.

5. The method for dynamic simulation of hinge wear failure of an operating mechanism of an electrically driven high-voltage circuit breaker according to claim 4 is characterized in that: Normal contact force F N The calculation adopts the LN nonlinear spring damping model considering hysteresis damping, as shown in formula (3): K is the contact stiffness coefficient of the material; the index n is 1.5 for metal contact; c e is the material recovery coefficient, which is determined according to the energy loss; is the initial collision velocity between the hinge shaft and the reaming hole; is the collision velocity between the hinge shaft and the reaming hole, is the clearance collision vector The derivative with respect to time t; Tangential friction force F t The modified Coulomb friction model is used, in which the friction coefficient is related to the tangential sliding velocity v t As shown in formula (4): v s is the critical speed of static friction; v d is the critical speed of maximum dynamic friction; μ s is the static friction coefficient; μ d is the sliding friction coefficient; sign(v t ) is a symbolic function; F t The calculation formula is shown in formula (5): F t =-μ(v t )F N (5)。 6. The method for dynamic simulation of hinge wear failure of an operating mechanism of an electrically driven high-voltage circuit breaker according to claim 5 is characterized in that: In step S3, the arm force equation is shown in formula (6): Among them, F RAx 、F Ray are the components of the reaction force of the transmission shaft on the crank arm on the x-axis and y-axis, respectively, n1 、F t1 are the hinge gap contact force and friction force on point B respectively; Load torque T calculated on the motor shaft L As shown in formula (7), the direction is clockwise: The force equation of the transmission connecting rod is shown in formula (8): Where G2 is the weight of the transmission connecting rod, F n2 、F t2 are the hinge gap contact force and friction force on point C′ respectively; In the opening stage, the insulating pull rod and the moving contact are regarded as a whole, and the motion force equation is shown in formula (9): Among them, F close is the arc extinguishing chamber self-closing force, F e For electric repulsion, G3, G4, G spr are the gravity of the insulating pull rod, the moving contact, and the overtravel spring, respectively. N is the pressure of the arc extinguishing chamber wall at point C, f C is the friction force on point C; In the overtravel stage, the insulating pull rod and the moving contact are discussed separately. Assuming that the spring is uniformly extended, the force equation is shown in formula (10): where F spr is the overtravel spring force, F n3 is the collision contact force between the moving and static contacts; The kinematic equation of the servo motor actuator is shown in formula (11): u d 、u q are the stator voltages of the d-axis and q-axis respectively, i d 、i q are the stator currents of the d-axis and q-axis respectively, L d , L q are the components of the stator inductance on the d-axis and q-axis, ω e is the motor electrical angular velocity, ψ f is the permanent magnet flux of the motor, ω m is the motor mechanical angular velocity, J is the motor rotor and load moment of inertia, B is the friction factor, T L With T f are load torque and friction torque respectively; According to the force conditions and equations (6) to (11), the accelerations of points B, B′, C′, C, and D are obtained, the velocities are obtained by integration, and the coordinate values ​​of B, B′, C′, C, and D are obtained by further integration.

7. The method for dynamic simulation of hinge wear failure of an operating mechanism of an electrically driven high-voltage circuit breaker according to claim 6 is characterized in that: In step S4, r1 and r2 are updated according to the coordinates of each point at the current moment, and then δ1 and δ2 are calculated by equation (2), and the hinge gap contact force and friction force are calculated according to equations (3) to (5) to obtain the force condition at the next moment.

8. The method for dynamic simulation of hinge wear failure of an operating mechanism of an electrically driven high-voltage circuit breaker according to claim 7 is characterized in that: Step S5 specifically includes the following steps: Assume that the angle between the hinge shaft and the reaming hole is θ c , which is called the contact angle, and its value range is [-π,π]; the clearance value C is a constant, and the clearance value after hinge wear changes with the contact angle θ c The function C(θ c ), which is defined as shown in formula (12): C(θ c )=C o [k c P(θ c )+1] (12) In formula (12), C o is the clearance value of the hinge in the initial healthy state; k c is the hinge wear coefficient, k c ≥0, and k c The larger the wear, the more serious the wear; P(θ c ) is the contact angle θ c The probability of; Assume that the total number of samples of contact angles in a closing and opening cycle is N, and θ c Divided into n intervals, falling within the interval The sample size on is N m , then P(θ c ) is calculated as shown in formula (13): First, the dynamic model with gap is established to simulate the hinge gap contact collision under the opening and closing movement of the motor-driven circuit breaker, and the distribution of different contact angles is sought. The probability formula of different contact angles is established according to formula (13), so as to obtain the gap function C(θ c ), through C(θ c ) replaces the gap value C to obtain the hinge failure dynamics simulation taking into account the actual wear conditions.

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