Automatic measurement method for opening and closing time and contact surface of multi-break magnetic field circuit breaker of generator

Abstract

The present invention discloses a method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator, comprising: step 1: installing a dot matrix thin film pressure sensor; step 2: installing and testing a shunt; step 3: measuring the closing time and timing of each break of the magnetic field circuit breaker; step 4: acquiring a mechanical signal of the thin film pressure sensor; step 5: calculating the area of ​​the break contact surface; step 6: judging whether the break contact pressure and contact area meet the requirements; step 7: calculating the opening time and timing of the magnetic field circuit breaker; step 8: judging whether the breaking time and timing of each break of the magnetic field circuit breaker meet the requirements. The method of the present invention can accurately measure the opening and closing time of the magnetic field circuit breaker break, the contact surface area and pressure distribution of the contact surface without untying the connecting wires.

Description

Technical Field

[0001] The present invention relates to the technical field of generator magnetic field circuit breakers, in particular to an automatic measurement method for the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator. Background Art

[0002] The generator field breaker is a crucial device connecting the excitation rectifier cabinet to the generator rotor. The tripping time of a multi-break field breaker must meet certain logical relationships. The main break must be shorter than the arc break, ensuring the field breaker transfers energy from the generator rotor's inductive load. Furthermore, the field breaker contacts are the current-carrying components of the switch, and inspection of the contact surface between the moving and stationary contacts is a crucial component of switch maintenance. Generally, the effective overlap area between the moving and stationary contacts must be no less than two-thirds of the total contact surface, and the contact pressure must meet standard pressure values.

[0003] Defects and shortcomings of existing technology:

[0004] Currently, when testing the opening and closing timing of a magnetic field circuit breaker, an oscilloscope is used to apply voltage signals to both ends of the break. Since the breakers are connected in series and parallel, a large number of switch connecting wires must be untied during the test, which is inconvenient to operate.

[0005] Furthermore, there is no effective method for accurately measuring contact area and contact pressure. The carbon paper method is a common method. Carbon paper is placed between the contacts. When the contacts close, an indentation is left on the paper. The color distribution of the indentation is used to estimate the contact area and surface area, and the depth of the indentation is used to estimate the pressure distribution. This method can roughly measure the contact area, but it cannot accurately measure the contact pressure. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator to solve the problems raised in the background technology.

[0007] To solve the above technical problems, the present invention adopts a technical solution: a method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator, which comprises the following steps:

[0008] Step 1: Install the dot matrix thin film pressure sensor: Before the test, the thin film pressure sensor needs to be calibrated to determine the relationship between the resistance and pressure of the thin film pressure sensor; the thin film pressure sensor is installed between the moving and static contacts of the magnetic field circuit breaker;

[0009] Step 2: Shunt meter installation and testing: Shunt meters are installed at both ends of the six breaks of the magnetic field circuit breaker. The shunt meter measurement signal is connected to the wave recording module of the signal acquisition and processing system for processing. The signal generator is a DC current source. When each break of the magnetic field circuit breaker is open, the current passes through the shunt meters connected in parallel at each break to form a current path. At this time, the shunt meter can measure a voltage value as the initial voltage. When each break of the magnetic field circuit breaker is closed, the current passes through each break and the parallel shunt meter to form a current path. At this time, the shunt meter measures a voltage value as the initial voltage.

[0010] Step 3: Measure the closing time and timing of each break of the magnetic field circuit breaker: Set the pre-recording time of the signal acquisition and processing system; after starting the test, the signal acquisition and processing system sends a closing command to the bus and starts command recording. The signal acquisition and processing system receives the voltage drop signal on both sides of the shunt through recording. The moment of voltage jump is the moment of the corresponding break action response; the closing command moment is the starting point of the closing moment of the magnetic field circuit breaker t 起点 The moment of shunt voltage jump is the closing moment of magnetic field circuit breaker. 终点 , magnetic field circuit breaker closing time = magnetic field circuit breaker closing time starting point t 起点 -End point of closing time of magnetic field circuit breaker t 终点 ;

[0011] Step 4: Obtain the mechanical signal of the thin film pressure sensor;

[0012] Step 5: Calculation of fracture contact surface area;

[0013] Step 6: Determine whether the fracture contact pressure and contact area meet the requirements;

[0014] Step 7: Calculation of the magnetic field circuit breaker opening time and sequence: Set the pre-recording time of the signal acquisition and processing system. After the test starts, the signal acquisition and processing system sends an opening command to the bus and starts command recording. The signal acquisition and processing system receives the voltage drop signal on both sides of the shunt through recording. The moment of voltage jump is the moment of the corresponding breaker action response. The opening command moment is the starting point of the opening moment of the magnetic field circuit breaker t 起点 The moment when the shunt voltage jumps is the end point of the opening of the magnetic field circuit breaker t 终点 , magnetic field circuit breaker opening time = magnetic field circuit breaker opening time starting point t 起点 - The end point of the opening moment of the magnetic field circuit breaker t 终点 ;

[0015] Step 8: Determine whether the breaking time and timing of each break of the magnetic field circuit breaker meet the requirements.

[0016] Preferably, in step 2, when each break of the magnetic field circuit breaker is disconnected, the voltage U1 across shunt 1 is the sum of the voltage U3 across shunt 3 and the voltage U4 across shunt 4, that is, U1=U3+U4; the voltage U2 across shunt 2 is the sum of the voltage U5 across shunt 5 and the voltage U6 across shunt 6, that is, U2=U5+U6; when a break of the magnetic field circuit breaker is closed, the current is shunted through the break, and the voltage across the shunt changes suddenly.

[0017] Preferably, step 3 includes the following process:

[0018] 3.1. Measure the closing start and end times of the main break 1 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by shunt meter 1;

[0019] 3.2. Measure the closing start and end times of the main break 2 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by shunt meter 2;

[0020] 3.3. Measure the closing start and end times of the arc breaker 1 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 3;

[0021] 3.4. Measure the closing start and end times of the arc breaker 2 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 4;

[0022] 3.5. Measure the closing start and end times of the arc breaker 3 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 5;

[0023] 3.6. Measure the closing start and end times of the arc breaker 4 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 6;

[0024] 3.7. Based on the calculation, the closing time of each break of the magnetic field circuit breaker is obtained to obtain the break closing timing sequence.

[0025] Preferably, in step 4, before obtaining the mechanical signal of the thin film pressure sensor, it is ensured that all the fractures of the magnetic field circuit breaker have been closed. Specifically, the starting time of obtaining the mechanical signal of the thin film pressure sensor must be greater than the maximum closing time of the magnetic field circuit breaker to form a contact surface pressure distribution.

[0026] Preferably, in step 5, when calculating the fracture contact surface area, the contact surface pressure distribution diagram is first gridded, and then the fracture contact surface area is calculated by summing up.

[0027] Preferably, the specific process of step 6 is: Condition 1: the fracture contact pressure is within the pressure setting standard value range, and the pressure distribution is within the set range, and the contact pressure is considered to meet the requirements; Condition 2: the contact area is greater than 2 / 3 of the contact area; when both conditions are met, go directly to the next step. If any one condition does not meet the requirements, it is prompted to adjust the magnetic field circuit breaker fracture.

[0028] Preferably, step 7 includes the following process:

[0029] 7.1. Measure the start and end times of the opening of the main break 1 of the magnetic field circuit breaker. The start time is the time when the signal acquisition and processing system issues the opening command, and the end time is the time of the voltage mutation measured by shunt meter 1.

[0030] 7.2. Measure the start and end times of the opening of the main break 2 of the magnetic field circuit breaker; the start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the time of the voltage mutation measured by shunt meter 2;

[0031] 7.3. Measure the start and end times of the arc-breaking opening of the magnetic field circuit breaker 1; the start time is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 3;

[0032] 7.4. Measure the start and end times of the arc-breaking opening of the magnetic field circuit breaker 2; the start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 4;

[0033] 7.5. Measure the start and end times of the arc-breaking opening of the magnetic field circuit breaker 3; the start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the time of the voltage mutation measured by the shunt meter 5;

[0034] 7.6. Measure the start and end times of the arc-breaking opening of the magnetic field circuit breaker 4; the start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 6;

[0035] 7.7. Based on the calculated opening time of each break of the magnetic field circuit breaker, the break opening timing sequence is obtained.

[0036] Preferably, the specific process of step 8 is: Condition 1: the breaking time of the break is within the set standard value range; Condition 2: the breaking sequence requires that the arc break is later than the main break time; if the above conditions are met, the test is completed; if not, it is prompted to adjust the magnetic field circuit breaker break, and the test is restarted after the adjustment.

[0037] Beneficial effects of the present invention:

[0038] (1) The present invention does not require untying the switch connection cable during testing. It can accurately measure the opening and closing time of the magnetic field circuit breaker and the contact surface area and pressure distribution of the contact without untying the connection line;

[0039] (2) The present invention solves the problem of difficult contact surface measurement. This method is currently the most accurate digital method for measuring the contact surface of magnetic field circuit breaker contacts.

[0040] (3) The method of the present invention can be promoted and applied in the maintenance of magnetic field circuit breakers in power plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The present invention is a flow chart of a method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator;

[0042] Figure 2 This is a schematic diagram of the installation of the thin film pressure sensor;

[0043] Figure 3 This is a schematic diagram of the structure where shunt meters are installed at both ends of the six fractures of the magnetic field circuit breaker;

[0044] Figure 4 This is a structural diagram of the wave recording module;

[0045] Figure 5 Schematic diagram of measurement of closing time and timing of each break;

[0046] Figure 6 Schematic diagram of pressure measurement distribution on the fracture contact surface;

[0047] Figure 7 This is a schematic diagram of the measurement of the opening time and timing of each break;

[0048] Figure 8 Design diagram for thin film pressure sensor array;

[0049] Figure 9 This is a schematic diagram of an automatic measuring device for the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator;

[0050] Figure 10 Pressure map for the sensor array and pressure measurement effects. DETAILED DESCRIPTION

[0051] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0052] Example 1: Figure 1 As shown, a method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator includes the following steps:

[0053] Step 1: Install the dot matrix thin film pressure sensor. Table 1 shows the parameter design of the dot matrix thin film pressure sensor. Figure 8 This is the design diagram of the thin film pressure sensor array. Before the test, the thin film pressure sensor needs to be calibrated to determine the relationship between the resistance of the thin film pressure sensor and the pressure. The measured relationship is: , where is the surface pressure value of the thin film pressure sensor; Test the resistance value kΩ for the thin film pressure sensor. The sensor is installed on Figure 2 Between the moving and static contacts of the demagnetization switch shown.

[0054] Table 1 Thin film pressure sensor parameter design

[0055]

[0056] Step 2: Install and test the shunt meter. Figure 3 As shown, shunt meters are installed at both ends of the six fractures of the magnetic field circuit breaker. The measurement signal of the shunt meter is connected to the recording module of the signal acquisition and processing system for processing. The recording module is as follows Figure 4 As shown, the wave recording module is integrated into the signal acquisition and processing system;

[0057] The signal generator is a DC current source capable of providing a DC current range of 0-500A. The current-limiting resistor is internal to the signal generator. To ensure accurate testing of the field circuit breaker's opening and closing times, currents exceeding 300A are used during measurement. When the field circuit breaker's terminals are open, the current forms a current path through the shunts connected in parallel at each terminal. At this point, the shunts measure a voltage value, which serves as the initial voltage.

[0058] When the switch is off, Figure 3 As shown, the voltage U1 across shunt 1 is the sum of the voltage U3 across shunt 3 and the voltage U4 across shunt 4, that is, U1=U3+U4; the voltage U2 across shunt 2 is the sum of the voltage U5 across shunt 5 and the voltage U6 across shunt 6, that is, U2=U5+U6;

[0059] When a certain break of the magnetic field circuit breaker is closed, the current is shunted through the break, and the voltage across the shunt meter suddenly changes;

[0060] The signal acquisition and processing system is equipped with 8 recording channels for measurement, which can automatically set the recording frequency, pre-recording time and recording time. The time difference of the 8-channel recording board synchronous recording does not exceed 6 microseconds;

[0061] After the measurement signal enters the filter, it is converted into AD and stored in RAM. The coordination of commands is controlled by the CPU. The CPU receives the instructions from the upper computer and processes the AD conversion data through the filter amplification circuit and the signal acquisition and processing system. Figure 5 This is a schematic diagram of the recording circuit structure.

[0062] Step 3: Measure the closing time and timing of each field circuit breaker break. To ensure accurate testing of the field circuit breaker's opening and closing times, use a current greater than 300A. When each break of the field circuit breaker is open, the current forms a current path through the shunts connected in parallel at each break. At this point, the shunts measure a voltage value that serves as the initial voltage.

[0063] When the switch is off, the voltage U1 across shunt 1 is the sum of the voltage U3 across shunt 3 and the voltage U4 across shunt 4, that is, U1=U3+U4; the voltage U2 across shunt 2 is the sum of the voltage U5 across shunt 5 and the voltage U6 across shunt 6, that is, U2=U5+U6;

[0064] When a certain break of the magnetic field circuit breaker is closed, the current is shunted through the break, and the voltage at both ends of the shunt meter changes suddenly. The pre-recording time of the signal acquisition and processing system is set to 5s. After the test starts, the signal acquisition and processing system sends a closing command to the bus and starts command recording. The signal acquisition and processing system receives the voltage drop signal on both sides of the shunt through recording. The moment of voltage jump is the moment when the corresponding break responds. The closing command moment is the starting point of the closing moment of the magnetic field circuit breaker break, t 起点 The moment of shunt voltage jump is the closing moment of magnetic field circuit breaker. 终点 , magnetic field circuit breaker closing time = magnetic field circuit breaker closing time starting point t 起点 -End point of closing time of magnetic field circuit breaker t 终点 .

[0065] Step 3.1: Calculate the start and end time of closing the main breaker 1 of the magnetic field circuit breaker. The closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 1, such as Figure 5 As shown, the main breaker closing time t1 = 274ms;

[0066] Step 3.2: Calculate the start and end time of closing the main breaker 2 of the magnetic field circuit breaker. The closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 2, such as Figure 5As shown, the main breaker closing time t2 = 275ms;

[0067] Step 3.3: Calculate the closing start and end time of the arc breaker 1. The closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 3, such as Figure 5 As shown, the main breaker closing time t3 = 261ms;

[0068] Step 3.4: Calculate the start and end time of closing the arc breaker 2 of the magnetic field circuit breaker. The closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 4, such as Figure 5 As shown, the main breaker closing time t4 = 262ms;

[0069] Step 3.5: Calculate the start and end time of closing the arc breaker 3 of the magnetic field circuit breaker. The closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 5, such as Figure 5 As shown, the main breaker closing time t5 = 262ms;

[0070] Step 3.6: Calculate the start and end time of closing of the arc breaker 4 of the magnetic field circuit breaker. The closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 6, such as Figure 5 As shown, the main breaker closing time t6 = 263ms;

[0071] Step 3.7: Based on the calculated closing time of each break of the magnetic field circuit breaker, you can use Figure 5 The method shown represents the break closing sequence;

[0072] Step 4: Obtain the sensor mechanical signal. Before obtaining the mechanical signal, ensure that all the breakers of the magnetic field circuit breaker have been closed. That is, the starting time of obtaining the mechanical signal must be greater than the maximum closing time of the magnetic field circuit breaker (t>t1-t6). Form the contact surface pressure distribution, such as Figure 6 shown.

[0073] Step 5: Calculate the fracture contact surface area. Figure 5 As shown in the figure, the contact surface pressure distribution diagram is meshed, that is, ; .

[0074] Step 6: Determine whether the contact pressure and contact area meet the requirements. If the contact pressure is within the set pressure range (maximum and minimum pressure values ​​can be set), and the pressure distribution is within the set range, the contact pressure is considered to meet the requirements; the contact area is greater than 2 / 3 of the contact area. If both conditions are met, proceed directly to the next step. If either condition is not met, a prompt is issued to adjust the magnetic field circuit breaker.

[0075] Step 7: Calculate the time and sequence of the magnetic field circuit breaker opening. Figure 3 and 4 To ensure accurate testing of the field circuit breaker's opening and closing times, a signal generator provides a DC current greater than 300A. When the field circuit breaker's openings are closed, current flows through each opening and the parallel shunt, forming a current path. The shunt then measures a voltage value, which serves as the initial voltage.

[0076] When the switch is disconnected, the current at the magnetic field circuit breaker is transferred to the parallel shunt, and the voltage at both ends of the shunt changes suddenly. The pre-recording time of the signal acquisition and processing system is set to 5s. After the test starts, the signal acquisition and processing system sends a trip command to the bus and starts command recording. The signal acquisition and processing system receives the voltage drop signal on both sides of the shunt through recording. The moment of voltage jump is the moment of the corresponding break action response. The trip command moment is the starting point of the trip moment of the magnetic field circuit breaker t 起点 The moment when the shunt voltage jumps is the end point of the opening of the magnetic field circuit breaker t 终点 , magnetic field circuit breaker opening time = magnetic field circuit breaker opening time starting point t 起点 - The end point of the opening moment of the magnetic field circuit breaker t 终点 ;

[0077] Step 7.1: Calculate the start and end time of the opening of the main break of the magnetic field circuit breaker 1. The opening start time is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 1, such as Figure 7 As shown, the main breaker 1 opening time t1 = 29ms;

[0078] Step 7.2: Calculate the start and end time of the opening of the main break 2 of the magnetic field circuit breaker. The opening start time is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 2, such as Figure 7 As shown, the main breaker 2 opening time t2 = 29ms;

[0079] Step 7.3: Calculate the start and end time of the arc-breaking opening of the magnetic field circuit breaker 1. The start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 3, such as Figure 7As shown, the arc-break 1 opening time t3 = 35ms;

[0080] Step 7.4: Calculate the start and end time of the arc-breaking opening of the magnetic field circuit breaker 2. The start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 4, such as Figure 7 As shown, the arc-break 2 opening time t4 = 35ms;

[0081] Step 7.5: Calculate the start and end time of the arc break of the magnetic field circuit breaker 3. The start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 5, such as Figure 7 As shown, the arc break 3 opening time t4 = 35ms;

[0082] Step 7.6: Calculate the start and end time of the arc-breaking opening of the magnetic field circuit breaker 4. The start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 6, such as Figure 7 As shown, the arc breaker 4 opening time t4 = 35ms.

[0083] Step 7.7: If Figure 7 As shown, the opening time of each break of the magnetic field circuit breaker is obtained according to the calculation, and the break opening timing sequence is obtained.

[0084] Step 8: Determine whether the interruption time and timing sequence of each magnetic field circuit breaker meet the requirements. If the interruption time is within the set standard value range (maximum and minimum interruption time standard values ​​can be set), the interruption time is considered to meet the requirements. The interruption timing requires that the arc interruption time be later than the main interruption time, that is, t3, t4, t5, and t6 are all greater than t1 and t2. If these conditions are met, the test is completed; if not, the switch adjustment prompt is prompted, and the test is restarted after the adjustment.

[0085] Example 2: A device for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator, such as Figure 9 As shown in FIG, the device consists of three parts: a signal generator, a thin film pressure sensor, a shunt meter, and a signal acquisition and processing system.

[0086] (1) The signal generator mainly provides 300A high current for the circuit;

[0087] (2) The shunt meter is mainly used to measure the voltage of each break of the magnetic field circuit breaker and to identify the closing and opening of the break of the magnetic field circuit breaker;

[0088] (3) Using customized dedicated flexible thin film pressure sensor arrays, such as Figure 10The sensor parameters are listed in Table 1. When unstressed, the thin-film pressure sensor has a resistance of 2 MΩ, and its resistance varies linearly with contact pressure. The thin sensor element and high sensor array density allow measurement of not only flat contacts but also curved surfaces. The force measurement accuracy can be enhanced by selecting an appropriate analog-to-digital converter. For example, a 12-bit ADC can achieve 4096 levels of pressure sensing.

[0089] (4) Signal processing system includes front-end conditioning circuit, digitizing circuit, wave recording system, embedded processor data processing software, LCD display, power management circuit, etc. Mainly responsible for test process management, such as Figure 2 As shown, the data is aggregated and processed, and finally the contact surface and pressure distribution diagram of the magnetic field circuit breaker are presented on the screen, as shown in Figure 10 shown.

[0090] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator, characterized by: It includes the following steps: Step 1: Install the dot matrix thin film pressure sensor: Before the test, the thin film pressure sensor needs to be calibrated to determine the relationship between the resistance and pressure of the thin film pressure sensor; The thin film pressure sensor is installed between the moving and static contacts of the magnetic field circuit breaker; Step 2: Shunt meter installation and testing: Shunt meters are installed at both ends of the six breaks of the magnetic field circuit breaker. The shunt meter measurement signal is connected to the wave recording module of the signal acquisition and processing system for processing. The signal generator is a DC current source. When each break of the magnetic field circuit breaker is open, the current passes through the shunt meters connected in parallel at each break to form a current path. At this time, the shunt meter can measure a voltage value as the initial voltage. When each break of the magnetic field circuit breaker is closed, the current passes through each break and the parallel shunt meter to form a current path. At this time, the shunt meter measures a voltage value as the initial voltage. Step 3: Measure the closing time and timing of each break of the magnetic field circuit breaker: Set the pre-recording time of the signal acquisition and processing system; after starting the test, the signal acquisition and processing system sends a closing command to the bus and starts command recording. The signal acquisition and processing system receives the voltage drop signal on both sides of the shunt through recording. The moment of voltage jump is the moment of the corresponding break action response; the closing command moment is the starting point of the closing moment of the magnetic field circuit breaker t 起点 The moment of shunt voltage jump is the closing moment of magnetic field circuit breaker. 终点 , magnetic field circuit breaker closing time = magnetic field circuit breaker closing time starting point t 起点 -End point of closing time of magnetic field circuit breaker t 终点 ; Step 4: Obtain the mechanical signal of the thin film pressure sensor; Step 5: Calculation of fracture contact surface area; Step 6: Determine whether the fracture contact pressure and contact area meet the requirements; Step 7: Calculation of the magnetic field circuit breaker opening time and sequence: Set the pre-recording time of the signal acquisition and processing system. After the test starts, the signal acquisition and processing system sends an opening command to the bus and starts command recording. The signal acquisition and processing system receives the voltage drop signal on both sides of the shunt through recording. The moment of voltage jump is the moment of the corresponding breaker action response. The opening command moment is the starting point of the opening moment of the magnetic field circuit breaker t 起点 The moment when the shunt voltage jumps is the end point of the opening of the magnetic field circuit breaker t 终点 , magnetic field circuit breaker opening time = magnetic field circuit breaker opening time starting point t 起点 - The end point of the opening moment of the magnetic field circuit breaker t 终点 ; Step 8: Determine whether the breaking time and timing of each break of the magnetic field circuit breaker meet the requirements.

2. The method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator according to claim 1, characterized in that: In step 2, when the respective breaks of the magnetic field circuit breaker are disconnected, the voltage U1 across shunt 1 is the sum of the voltage U3 across shunt 3 and the voltage U4 across shunt 4, i.e., U1=U3+U4; the voltage U2 across shunt 2 is the sum of the voltage U5 across shunt 5 and the voltage U6 across shunt 6, i.e., U2=U5+U6; when a break of the magnetic field circuit breaker is closed, the current is shunted through the break, and the voltage across the shunt changes suddenly.

3. The method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator according to claim 2, characterized in that: Step 3 includes the following process: 3.

1. Measure the closing start and end time of the main break 1 of the magnetic field circuit breaker; The closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by shunt meter 1; 3.

2. Measure the closing start and end times of the main break 2 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by shunt meter 2; 3.

3. Measure the closing start and end times of the arc breaker 1 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 3; 3.

4. Measure the closing start and end times of the arc breaker 2 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 4; 3.

5. Measure the closing start and end times of the arc breaker 3 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 5; 3.

6. Measure the closing start and end times of the arc breaker 4 of the magnetic field circuit breaker; the closing start time is the time when the signal acquisition and processing system issues the closing command, and the end time is the voltage mutation time measured by the shunt meter 6; 3.

7. Based on the calculation, the closing time of each break of the magnetic field circuit breaker is obtained to obtain the break closing timing sequence.

4. The method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator according to claim 1, characterized in that: In step 4, before obtaining the mechanical signal of the thin film pressure sensor, ensure that all the fractures of the magnetic field circuit breaker have been closed. Specifically, the starting time of obtaining the mechanical signal of the thin film pressure sensor must be greater than the maximum closing time of the magnetic field circuit breaker to form a contact surface pressure distribution.

5. The method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator according to claim 1, characterized in that: In step 5, when calculating the fracture contact surface area, the contact surface pressure distribution diagram is first grid-divided, and then the fracture contact surface area is calculated by summing up.

6. The method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator according to claim 1, characterized in that: The specific process of step 6 is as follows: Condition 1: The fracture contact pressure is within the pressure setting standard value range, and the pressure distribution is within the set range, and the contact pressure is considered to meet the requirements; Condition 2: The contact area is greater than 2 / 3 of the contact area; when both conditions are met, directly proceed to the next step; if any condition does not meet the requirements, a prompt is given to adjust the magnetic field circuit breaker fracture.

7. The method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator according to claim 2, wherein step 7 comprises the following process: 7.

1. Measure the start and end times of the opening of the main break 1 of the magnetic field circuit breaker. The start time is the time when the signal acquisition and processing system issues the opening command, and the end time is the time of the voltage mutation measured by shunt meter 1. 7.

2. Measure the start and end times of the opening of the main break 2 of the magnetic field circuit breaker; the start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the time of the voltage mutation measured by shunt meter 2; 7.

3. Measure the start and end times of the arc-breaking opening of the magnetic field circuit breaker 1; the start time is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 3; 7.

4. Measure the start and end times of the arc-breaking opening of the magnetic field circuit breaker 2; the start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 4; 7.

5. Measure the start and end times of the arc-breaking opening of the magnetic field circuit breaker 3; the start time of the opening is the time when the signal acquisition and processing system issues the opening command, and the end time is the time of the voltage mutation measured by the shunt meter 5; 7.

6. Measure the start and end time of the arc-breaking 4-way trip of the magnetic field circuit breaker; The opening start time is the time when the signal acquisition and processing system issues the opening command, and the end time is the voltage mutation time measured by the shunt meter 6; 7.

7. Based on the calculated opening time of each break of the magnetic field circuit breaker, the break opening timing sequence is obtained.

8. The method for automatically measuring the opening and closing time and contact surface of a multi-break magnetic field circuit breaker of a generator according to claim 1, characterized in that: The specific process of step 8 is as follows: Condition 1: the breaking time of the break is within the set standard value range; Condition 2: the breaking sequence requires that the arc break is later than the main break; if the above conditions are met, the test is completed; if not, it is prompted to adjust the magnetic field circuit breaker break, and the test is restarted after the adjustment.

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