Method for simulating hinge wear failure of operating mechanism of electric drive high voltage circuit breaker

Abstract

The present application relates to a kind of electric drive high-voltage circuit breaker operating mechanism hinge wear fault dynamics simulation method, belong to high-voltage circuit breaker fault diagnosis technical field, comprising the following steps: S1: establish the kinematics model of high-voltage circuit breaker based on servo motor driving;S2: determine initial state, calculate the stress of hinge gap;S3: start servo motor, according to the stress condition of crank arm, transmission connecting rod, open distance stage / overtravel stage, the kinematics equation of servo motor operating mechanism, the coordinates of each point at current time are calculated;S4: according to the coordinates of each point at current time, update r1, r2, calculate δ1, δ2, calculate the contact force and friction of hinge gap clearance, obtain the stress condition of next time;S5: repeat steps S3-S4, iteration obtains the stress and movement of each time motor direct drive operating circuit breaker;S6: analyze the collision angle variation of hinge shaft and hinge hole in a movement cycle, establish the clearance value after wear failure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-voltage circuit breaker fault diagnosis, and relates to a kind of electric drive high-voltage circuit breaker operating mechanism hinge wear fault dynamics simulation method, BACKGROUND

[0002] High-voltage circuit breakers use motor direct drive operating mechanism, compared with traditional spring, electromagnetic, hydraulic operating mechanism, it has less parts, simple structure, and in the process of opening and closing, it can rely on motor control system to adjust the operating mechanism output to match the load, has higher reliability and intelligent degree, is the important development direction of high-voltage circuit breaker adapting to new power system. High-voltage circuit breaker is the only control and protection equipment in power system primary equipment, is an important control equipment to connect and disconnect the circuit, remove and isolate faults, if a fault occurs, it will cause great harm to the power grid. High-voltage circuit breaker has a large short-time load during opening and closing, often accompanied by severe transient impact, which can easily cause wear at the hinge joint of the operating mechanism rod. Therefore, it is difficult to simulate and diagnose the hinge wear fault of the servo electric drive high-voltage circuit breaker operating mechanism. Therefore, it is very important to develop a hinge wear state simulation method for fault analysis and early diagnosis of circuit breakers.

[0003] At present, the fault state data of most circuit breakers is obtained through simulation fault experiment, although this method can obtain more reliable fault data, but the experimental platform has high cost and complex process, and the sample data is insufficient. Moreover, the experiment is mainly for fault phenomena such as rack bolt loosening and mechanism jamming, which is difficult to simulate and analyze the fault mechanism caused by hinge wear defect, and lacks modeling analysis of this kind of fault of circuit breaker.

[0004] In summary, high-voltage circuit breaker has a large short-time load during opening and closing, often accompanied by severe transient impact, which can easily cause wear at the hinge joint of the operating mechanism rod. The data used in the existing circuit breaker fault diagnosis is obtained by experiment, which has high cost and is space-constrained, and the sample data is insufficient. Moreover, it is difficult to simulate and diagnose the hinge wear fault of the servo electric drive high-voltage circuit breaker operating mechanism. SUMMARY

[0005] Therefore, the purpose of the application is to provide a kind of electric drive high-voltage circuit breaker operating mechanism hinge wear fault dynamics simulation method, through the establishment of hinge wear state fault model of circuit breaker by dynamics model, simulation model data can be obtained, solve the problem of high experimental cost and insufficient sample size, and the establishment of fault model is more conducive to analyzing the fault mechanism.

[0006] To achieve the above purpose, the application provides the following technical scheme:

[0007] A kind of electric drive high-voltage circuit breaker operating mechanism hinge wear fault dynamics simulation method, comprising the following steps:

[0008] S1: Establish a kinematic model of a 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 based on 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 equations of the servo motor operating mechanism;

[0011] S4: Update r1 and r2 based on 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 reaming hole center point B′, 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 reaming hole center point C; 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 situation at the next moment;

[0012] S5: Repeat steps S3-S4 to iteratively obtain the force and motion of the circuit breaker under direct motor drive at each moment;

[0013] S6: Analyze the change in the collision angle between the hinge shaft and the reaming hole in a hinge motion cycle, and establish the gap 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 link, 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 link, respectively; C is the bottom of the insulating rod, and points C′ and C are the hinge axis and the center of the reaming hole of the hinge between the transmission link and the insulating 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] 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 gap vector angle at 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 link and the insulating rod.

[0019] Furthermore, 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 positions of each point are calculated by formula (1); and δ1 and δ2 are known, so the hinge gap force can be calculated.

[0020] Furthermore, 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 the 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] vs v0 is the critical speed of static friction; v d v0 is the maximum critical speed of dynamic friction; μ s μ is the coefficient of static friction; μ d μ is the coefficient of sliding friction; sign(v t ) is the sign function;

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

[0033] F t = -μ(v t )F N (5).

[0034] Further, in step S3, the force equation of the crank arm is shown in equation (6):

[0035]

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

[0037] The load torque T L on the motor shaft is calculated as shown in equation (7), and the direction is clockwise:

[0038]

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

[0040]

[0041] where G2 is the gravity of the transmission connecting rod, F n2 x, F t2 y are the contact force and friction force of the hinge gap at point C';

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

[0043] where F close is the self-closing force of the arc extinguishing chamber, F e is the electric repulsion, G3, G4, G spr are the gravities of the insulating pull rod, the moving contact, and the overtravel spring, respectively, F N is the normal contact force at point C, f C is the friction force at point C;

[0044] The over-travel stage insulation pull rod and the moving contact are discussed separately, assuming that the spring is uniformly stretched, and the force equation is shown as equation (10):

[0045]

[0046] where F spr is the over-travel spring force, F n3 is the collision contact force of the moving and static contacts;

[0047] The kinematic equation of the servo motor operating mechanism is shown as equation (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 in the d-axis and q-axis respectively, ω e is the motor electric angular velocity, ψ f is the motor permanent magnet flux linkage, 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 and T f are the load torque and friction torque respectively;

[0050] According to the force condition and equations (6)-(11), the accelerations of points B, B', C', C and D are obtained, the velocities are obtained by integration, and the coordinates of points B, B', C', C and D are obtained by further integration.

[0051] Further, in step S4, r1 and r2 are updated according to the coordinates of each point at the current time, then δ1 and δ2 are obtained through equation (2), and the hinge gap contact force and friction are calculated according to equations (3)-(5), and the force condition at the next time is obtained.

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

[0053] Let the angle when the hinge shaft contacts the hinge hole be θ c , which is called the contact angle, and the value range is [-π, π]; the gap value C is a constant, and the gap value after the hinge wears is a function C(θ c ) that changes with the contact angle θ c , which is defined as shown in equation (12):

[0054] C(θ c ) = C o [k c P(θc )+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 value, the more serious the wear condition; P(θ c ) is the contact angle θ c The probability of contact angle; suppose the total number of samples of contact angle statistics 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 situation under the opening and closing movement of the motor-driven circuit breaker, and the distribution of different contact angles is sought. According to formula (13), the probability formula of different contact angles is established, and the gap function C(θ c ), through C(θ c ) to replace the gap value C, and obtain the hinge failure dynamics simulation considering the actual wear situation.

[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 levels;

[0060] (2) The contact angle between the hinge shaft and the reaming hole in the actual opening and closing process 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) that varies with the contact angle based on the probability distribution of the contact angle between the hinge shaft and the reaming hole in the opening and closing process. c ), which can better reflect the clearance characteristics of the hinge after actual wear;

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

[0062] Additional advantages, objects, and features of the application will be apparent to those skilled in the art upon examination of the following specification. It is intended to cover by such BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to make the objects, technical solutions and advantages of the present application clearer, the preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings, in which:

[0064] Figure 1 Structure diagram of high-voltage circuit breaker driven by servo motor;

[0065] Figure 2 Structure diagram of hinge;

[0066] Figure 3 Kinematics model of circuit breaker with gap;

[0067] Figure 4 Force conditions of hinge gap, wherein (a) is that the hinge shaft is aligned with the center of the hinge hole, (b) is that the hinge shaft does not contact the hinge hole, and (c) is that the hinge shaft collides with the hinge hole;

[0068] Figure 5 Force condition of crank arm;

[0069] Figure 6 Force condition of transmission connecting rod;

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

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

[0072] Figure 9 Contact angle probability distribution P(θ c ) of crank arm hinge in the opening process of a circuit breaker;

[0073] Figure 10 Crank arm hinge gap C(θ c ) of a circuit breaker;

[0074] Figure 11 Moving contact stroke before and after the wear of the crank arm hinge;

[0075] Figure 12 Moving contact speed before and after the wear of the crank arm hinge;

[0076] Figure 13 Motor output torque before and after the wear of the crank arm hinge;

[0077] Figure 14 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 means of 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 are only schematic illustrations of the basic concept of the present invention, 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 merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not 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 complex.

[0080] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the embodiments of the present invention.

[0081] The structure of high voltage circuit breaker based on servo motor drive is as follows Figure 1 As shown, the servo motor rotor is connected to the circuit breaker body via a drive shaft. The servo motor's output torque drives the circuit breaker. The circuit breaker body is primarily composed of hinged components, including a crank arm, a transmission connecting rod, and an insulating pull rod. Rotation of the crank arm drives the transmission connecting rod, which in turn drives the insulating pull rod vertically, ultimately driving the overtravel spring and moving contact.

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

[0083] Figure 1 The kinematic model of the circuit breaker is as follows Figure 3As 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. 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 r1 is the clearance 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; θ c1 is the gap vector angle at 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 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 shaft is aligned with the center of the reaming hole, and C is the clearance value; (b) is the case where the hinge shaft 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) is and In the reverse 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 the normal contact force F n 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 exponent 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, 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 Related, 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. F 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 in the figure, l1 is the length of the crank arm, S1 is the center of mass of the crank arm, and p1 is the distance from the center of mass of the crank arm to the end point. θ1 is the angle between the crank arm and the horizontal line, and its value is consistent with the position angle of the motor rotor. G1 is the weight of the crank arm, 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 Bt are the normal velocity and tangential velocity at point B, 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 on the transmission connecting rod is as follows Figure 6 As shown, l2 is the length of the transmission connecting rod, S2 is the center of mass of the transmission connecting rod, p2 is the distance from the center of mass of the crank arm to the end point, G2 is the gravity of the transmission connecting rod, V C′n 、V C′tare 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 phase, the insulating rod and the moving contact are considered as a whole, and the force acting on them is as follows: Figure 7 As shown. close is the arc extinguishing chamber self-closing force, F e For electric repulsion, G3, G4, G spr are the gravity of the insulating rod, the moving contact, and the overtravel spring, respectively. N is the normal contact force 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 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 operating mechanism 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.

[0108]

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

[0110] ①Determine the initial state: θ1 is the initial angle of the motor rotor, which is determined by the opening and closing distance of the circuit breaker and the overtravel; B and B' coincide, C' and C coincide, r1 and r2 are both 0, and the positions of various points can be obtained according to formula (1), wherein r1 is the gap vector of the hinge shaft center point B of the crank arm and the hinge connection of the transmission connecting rod pointing to the hinge hole center point B', and r2 is the gap vector of the hinge shaft center point C' of the transmission connecting rod and the hinge connection of the insulating pull rod pointing to the hinge hole center point C. And δ1 and δ2 are known, the hinge gap force can be obtained, the hinge gap force can be divided into the normal contact force F N and the tangential friction force F t , which can be obtained through formulas (3)-(5); wherein δ1 is the gap collision vector of the hinge connection of the crank arm and the transmission connecting rod, and δ2 is the gap collision vector of the hinge connection of the transmission connecting rod and the insulating pull rod

[0111] ②According to the force condition and formulas (6)-(11), the accelerations of points B, B', C', C and D can be obtained, the speeds can be obtained by integration, and the coordinate values can be obtained by further integration;

[0112] ③Update r1 and r2 according to the coordinates of B, B', C' and C at this moment, obtain δ1 and δ2 through formula (2), calculate the hinge gap contact force and friction force according to formulas (3)-(5), and obtain the force condition at the next moment;

[0113] Repeat steps ② and ③ to obtain the force and motion conditions of the motor direct drive circuit breaker 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 the wear condition at the hinge is often not uniformly distributed, but concentrated at some angles, therefore, the hinge gap value after wear failure is established according to the change of the collision angle of the hinge shaft and the hinge hole in a movement cycle through the circuit breaker dynamic model. The angle of the hinge shaft and the hinge hole when in contact is θ c , which is called the contact angle, and the value range is [-π, π]. Generally, the gap value C is a constant, and the gap value after hinge wear is a function C(θ c ) that changes with the contact angle 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 value, the more serious the wear condition; P(θ c ) is the contact angle θ c Assume that the total number of contact angle samples 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 situation under the opening and closing movement of the motor-driven circuit breaker, and the distribution of different contact angles is sought. According to formula (13), the probability formula of different contact angles is established, and the gap function C(θ c ), through C(θ c ) instead of the clearance value C, a hinge failure dynamics simulation considering actual wear conditions can be obtained.

[0119] To verify the effect, the initial value of the hinge gap at the hinge 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 Figure 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 the range of -1.6 to -0.8 rad, so the hinge wear in this range is more serious. The clearance function C(θ c )like Figure 10 As shown in the figure, 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 formation of the moving contact before and after the wear of the crank arm hinge, the displacement of the moving contact, the output torque of the servo motor, and the motor phase current are as follows: Figures 11-14 As shown in the figure, wear increases the total displacement of the moving contact due to the increased gap, and the moving contact oscillates more severely. There is also significant rebound during movement, and the moving contact opening speed decreases after wear. Furthermore, the motor's output torque and phase current increase after the hinge arm wears. The hinge wear state simulation fault model based on the present invention, which includes a hinge gap, can effectively obtain moving contact travel information and electrical information about the motor operating mechanism.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. 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 solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for dynamic simulation of hinge wear failure in an operating mechanism of an electrically driven high-voltage circuit breaker, characterized by: The following steps are involved: S1: Establish a kinematic model of a 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 based on 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 equations of the servo motor operating mechanism; S4: Update the coordinates of each point according to the current moment r 1 and r 2, among which 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 and δ 2, among which 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; the hinge gap contact force and friction force are calculated to obtain the force situation at the next moment; S5: Repeat steps S3-S4 to iteratively obtain the force and motion of the circuit breaker under direct motor drive at each moment; S6: Analyze the change in the collision angle between the hinge shaft and the reaming hole in a hinge motion cycle, and establish the gap value after wear failure based on the change distribution of the collision angle.

2. The dynamic simulation method for hinge wear failure of the 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 link, 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 link, respectively; C is the bottom of the insulating rod, and points C′ and C are the hinge axis and the center of the reaming hole of the hinge between the transmission link and the insulating 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; (1)； 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 c1 is the clearance vector angle at the hinge connection between the crank arm and the transmission link, 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 rod.

3. The dynamic simulation method for hinge wear failure of the operating mechanism of an electrically driven high-voltage circuit breaker according to claim 2 is characterized in that: 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; B coincides with B', C' coincides with C, r 1 and r 2 are all 0, and the position of each point is calculated by formula (1); and δ 1 and δ 2 is known, 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' , the gap collision vector The calculation is shown in formula (2): (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 normal contact force F n Tangential friction 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, 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): (3) K is the contact stiffness coefficient of the material; the index n For metal contacts, take 1.5; 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 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): (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): (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, characterized in that: In step S3, the arm force equation is shown in formula (6): (6) in F RAx 、 F Ray are the components of the reaction force of the transmission shaft on the crank arm in the x-axis and y-axis respectively, F n1 、 F t1 are the hinge gap contact force and friction force at point B respectively; Load torque calculated on the motor shaft T L As shown in formula (7), the direction is clockwise: (7) The force equation of the transmission connecting rod is shown in formula (8): (8) in G 2 is the weight of the transmission connecting rod, F n2 、 F t2 are the hinge gap contact force and friction force at point C′ respectively; In the opening stage, the insulating rod and the moving contact are regarded as a whole, and the motion force equation is shown in formula (9): (9) in 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 rod, moving contact and overtravel spring respectively. F N is the normal contact force at point C, f C is the friction force at point C; The insulating rod and the moving contact are discussed separately in the overtravel stage. Assuming that the spring is uniformly extended, the force equation is shown in formula (10): (10) in 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 operating mechanism is shown in formula (11): (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 respectively, 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 moment of inertia of the motor rotor and load, B is the friction factor, T L and 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, characterized in that: In step S4, the coordinates of each point at the current moment are updated r 1 and r 2, and then use formula (2) to find δ 1 and δ 2, and calculate the hinge gap contact force and friction force according to equations (3) to (5) to obtain the force situation 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, 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 the hinge wears changes with the contact angle θ c The changing function C( θ c ), which is defined as shown in formula (12): (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 bigger it is, the more serious the wear and tear will be; P ( θ c ) is the contact angle θ c The probability of; suppose the total number of samples of contact angles in a closing and opening cycle is N ,Will θ c Divided into n interval, falls within the interval m The sample size on N m ,but P ( θ c ) is calculated as shown in formula (13): (13) First, the dynamic model with gap is established to simulate the hinge gap contact collision under the opening and closing motion of the motor-driven circuit breaker, and the distribution of different contact angles is sought. According to formula (13), the probability formula of different contact angles is established, and the gap function C( θ c ), through C( θ c ) replaces the gap value C to obtain the hinge failure dynamics simulation considering the actual wear situation.

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