On-line monitoring device for mechanical characteristics of circuit breaker and monitoring method thereof

Abstract

The invention discloses a circuit breaker mechanical characteristic on-line monitoring device and a monitoring method thereof, and the device comprises a sound signal obtaining module which is used for collecting an action sound signal in the opening and closing operation process of a circuit breaker, and a microprocessor unit starts a vibration signal obtaining module, a displacement resistance obtaining module and a current signal obtaining module based on the sound signal; the vibration signal acquisition module is used for acquiring vibration signals in the opening and closing process of the circuit breaker; the displacement resistance acquisition module comprises a linear potentiometer connected with a circuit breaker pull rod; the current signal acquisition module is used for acquiring a current signal of the circuit breaker operating mechanism; according to the online monitoring device and method for the mechanical characteristics of the circuit breaker, indexes such as the opening and closing speed, the total stroke, the opening distance, the overtravel, the opening and closing time, the energy storage driving motor coil current and the opening and closing driving electromagnet coil current of the circuit breaker can be monitored on line, and then the running state of the circuit breaker is obtained, so that safe running of the circuit breaker is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of power technology, and in particular to an online monitoring device and method for the mechanical characteristics of circuit breakers. Background Technology

[0002] In recent years, the State Grid Corporation of China has continued to increase investment in the construction of a digital and intelligent robust power grid to promote the green and low-carbon transformation of energy, and has proposed the construction goal of a "digital and intelligent robust power grid." A digital and intelligent power grid requires the digitalization and informatization of equipment operating status, improving the level of equipment status prediction and the accuracy of fault diagnosis. Among these requirements, the intelligentization of switchgear is an important prerequisite for building a ubiquitous power Internet of Things. Intelligent switchgear allows maintenance personnel to use equipment operating information to diagnose faults.

[0003] The mechanical characteristics of a circuit breaker are a crucial indicator of its performance. These characteristics primarily include opening and closing speeds, total travel, opening distance, overtravel, opening and closing time, energy storage drive motor coil current, and opening and closing drive electromagnet coil current. Currently, there is a lack of monitoring devices specifically designed for circuit breaker mechanical characteristics, making accurate and timely monitoring of circuit breaker operation difficult. Therefore, this invention proposes an online monitoring device and method for circuit breaker mechanical characteristics. Summary of the Invention

[0004] Purpose of the invention: To provide an online monitoring device and method for the mechanical characteristics of a circuit breaker, which can monitor online indicators such as the opening and closing speed, total stroke, opening distance, overtravel, opening and closing time, energy storage drive motor coil current, and opening and closing drive electromagnet coil current of the circuit breaker, thereby obtaining the operating status of the circuit breaker to ensure its safe operation.

[0005] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0006] In the first aspect, an online monitoring device for the mechanical characteristics of a circuit breaker is provided, including a monitoring signal acquisition unit and a microprocessor unit;

[0007] The monitoring signal acquisition unit includes:

[0008] The sound signal acquisition module is used to collect the sound signals of the circuit breaker's opening and closing operations.

[0009] The vibration signal acquisition module is used to collect vibration signals during the opening and closing process of the circuit breaker;

[0010] The displacement resistance acquisition module is used to collect the displacement resistance value of the circuit breaker rod during the opening and closing process of the circuit breaker.

[0011] The current signal acquisition module is used to acquire the current signal of the circuit breaker operating mechanism;

[0012] The microprocessor unit is configured as follows:

[0013] In response to receiving the sound signal, the vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module are activated.

[0014] Based on the acquired vibration signal, the execution status of the circuit breaker's opening and closing actions is determined;

[0015] Based on the change in the obtained displacement resistance value, the total stroke of the moving and stationary contacts of the circuit breaker arc extinguishing chamber is obtained.

[0016] Based on the characteristics of the current signal changing over time, a current-time curve is generated, and the operating status of the circuit breaker operating mechanism is determined according to the current-time curve.

[0017] In some possible embodiments, the sound signal acquisition module includes a microphone;

[0018] The microphone is installed at the lever and sends the collected sound signal to the microprocessor unit, so that the microprocessor unit sends a monitoring command;

[0019] The microprocessor unit identifies the start and end times of the sound signal relative to a preset threshold, and calculates the switching time of the circuit breaker opening and closing based on the time difference between the start and end times.

[0020] In a further embodiment, the microprocessor unit includes a first time module, a second time module, and a time calculation module arranged sequentially;

[0021] The first time module is used to obtain the start time, the second time module is used to obtain the end time, and the time calculation module is used to calculate the time difference.

[0022] In a further embodiment, the vibration signal acquisition module includes a vibration sensor and a dual-T 50Hz notch filter circuit, with the vibration sensor installed at the pull rod.

[0023] The output terminal of the vibration sensor is connected to the input terminal V1 of the double-T type 50Hz notch filter.

[0024] In a further embodiment, the displacement resistance acquisition module includes a linear potentiometer connected to the pull rod, and the microprocessor unit obtains the total stroke of the moving and stationary contacts of the circuit breaker arc extinguishing chamber based on the resistance value change of the linear potentiometer caused by the movement of the pull rod.

[0025] The resistance value of the linear potentiometer changes linearly with the displacement stroke, and the resistance value is 0-10kΩ within the full stroke range of 0-50mm.

[0026] In a further embodiment, the current signal acquisition module includes an energy storage measurement module, the operating mechanism includes an energy storage drive motor, the energy storage measurement module is used to acquire the energy storage current signal of the energy storage drive motor coil, and the microprocessor unit generates an energy storage current-time curve based on the characteristics of the energy storage current signal changing with time to determine the operating status of the energy storage drive motor.

[0027] The energy storage measurement module includes a Hall current sensor for the energy storage drive motor coil.

[0028] In a further embodiment, the current signal acquisition module further includes an electromagnetic measurement module, and the operating mechanism further includes a circuit breaker drive electromagnet. The electromagnetic measurement module is used to acquire the electromagnetic current signal of the circuit breaker drive electromagnet coil. The microprocessor unit generates an electromagnetic current-time curve based on the characteristics of the electromagnetic current signal changing with time, and determines the operating status of the circuit breaker action.

[0029] The electromagnetic measurement module includes a Hall current sensor for the electromagnet coil used for opening and closing the circuit breaker.

[0030] In a further embodiment, a power supply unit is also included, the power supply unit comprising an open-type CT power extraction module;

[0031] The open-type CT power supply module includes:

[0032] The power-collecting CT submodule acquires electrical energy from the cable and outputs alternating voltage;

[0033] The power conversion submodule is electrically connected to the power CT submodule and is used to convert the alternating voltage into a direct current voltage and supply power to the microprocessor unit.

[0034] In a further embodiment, the power conversion submodule includes a power supply circuit, a stabilization circuit, and a protection circuit;

[0035] The power supply circuit includes a rectifier bridge D1, a resistor R4, an electrolytic capacitor C10, a tantalum capacitor C11, a Zener diode D3, a tantalum capacitor C12, a voltage monitoring chip S80848, a diode D4, a current-limiting resistor R6, a ceramic capacitor C13, and a MOSFET Q1. The rectifier bridge D1, the electrolytic capacitor C10, and the tantalum capacitor C11 are connected in parallel. The resistor R4 is connected in series between the rectifier bridge D1 and the electrolytic capacitor C10. The Zener diode D3 is connected in series with the tantalum capacitor C12 and then in parallel with the tantalum capacitor C11. The input terminal of the voltage monitoring chip S80848 is connected in series with the Zener diode D3 and the tantalum capacitor C12. The output terminal is connected in series with the diode D4, the current-limiting resistor R6, and the MOSFET Q1. The drain and source of the MOSFET Q1 are connected in parallel with the ceramic capacitor C13.

[0036] The stabilizing circuit includes a diode D5 and a resistor R5. One end of the diode D5 is connected in series between the diode D4 and the current-limiting resistor R6, and the other end is connected in series with the resistor R5.

[0037] The protection circuit includes a high-voltage capacitor C8, a high-voltage capacitor C9, a bidirectional TVS transient suppression transistor D2, a resistor R7, and a resistor R8. The high-voltage capacitor C8 is connected in parallel with the rectifier bridge D1, the high-voltage capacitor C9 is connected in parallel with the bidirectional TVS transient suppression transistor D2, and the resistors R7 and R8 are connected in series with the resistor R4.

[0038] Secondly, a method for online monitoring of the mechanical characteristics of a circuit breaker is provided, employing the aforementioned online monitoring device. The method includes the following steps:

[0039] Acquire the sound signals of the circuit breaker during the opening and closing process;

[0040] Based on the sound signal, the microprocessor unit activates the vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module to execute online monitoring commands on the mechanical characteristics of the circuit breaker.

[0041] The vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module feed back various mechanical characteristic data during the monitoring process to the microprocessor unit;

[0042] The microprocessor unit processes and analyzes the various mechanical characteristic data to complete the online monitoring of the circuit breaker's mechanical characteristics.

[0043] The beneficial effects of this invention are as follows: A vibration sensor is used to assist in determining whether the circuit breaker has operated. During the opening and closing process, the circuit breaker operating mechanism generates strong vibration information. If a vibration signal is collected, it indicates that the circuit breaker has performed the opening and closing operation. Simultaneously, an audio signal is used as the command signal for collecting the circuit breaker's opening and closing operation information, eliminating the need to connect the auxiliary contacts of the circuit breaker's opening and closing buttons to the device. A Hall current sensor is used to collect the current of the energy storage drive motor coil and the current of the opening and closing drive electromagnet coil. The opening and closing operation time is determined based on the initial change in the current curve of the opening and closing drive electromagnet coil. This method is more accurate than the traditional method of determining the circuit breaker's opening and closing operation time using the change time of the opening and closing status switch, overcoming the time measurement error caused by the delay of the opening and closing buttons relying on relay contacts. A displacement sensor installed at the lower end of the circuit breaker vacuum bulb is used to measure the total stroke of the circuit breaker. Combined with the vibration sensor's measurement of the abrupt change points during the circuit breaker's opening and closing operation, the points of initial opening and closing are determined, and the opening distance and overtravel are calculated. Attached Figure Description

[0044] Figure 1 This is a circuit principle block diagram of an online monitoring device for the mechanical characteristics of a circuit breaker provided in one embodiment of the present invention.

[0045] Figure 2 This is a circuit diagram of a double-T notch filter provided in one embodiment of the present invention.

[0046] Figure 3 This is a schematic diagram illustrating the change of sound intensity over time, provided in one embodiment of the present invention.

[0047] Figure 4 This is a schematic diagram of the theoretical curve of the closing moving contact stroke provided in one embodiment of the present invention.

[0048] Figure 5 This is a schematic diagram of the theoretical curve of the tripping moving contact provided in one embodiment of the present invention.

[0049] Figure 6 This is a schematic diagram of the theoretical curve of the drive current of the energy storage drive motor provided in one embodiment of the present invention.

[0050] Figure 7 This is an equivalent circuit diagram of the opening and closing drive electromagnet coil provided in one embodiment of the present invention.

[0051] Figure 8 This is a schematic diagram of the theoretical curve of the iron core movement process and its driving current provided in one embodiment of the present invention.

[0052] Figure 9 This is a circuit diagram of a communication module provided in one embodiment of the present invention.

[0053] Figure 10This is a circuit diagram of a display module provided in one embodiment of the present invention.

[0054] Figure 11 This is a TF card storage circuit diagram provided in one embodiment of the present invention.

[0055] Figure 12 This is a circuit diagram of a microprocessor unit provided in one embodiment of the present invention.

[0056] Figure 13 This is a circuit diagram of an open-type CT power supply module provided in one embodiment of the present invention. Detailed Implementation

[0057] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0058] The present invention will be further described in detail below with reference to the accompanying drawings.

[0059] Example 1: Refer to Figure 1 This embodiment discloses an online monitoring device for the mechanical characteristics of a circuit breaker; it includes a sound signal acquisition module, a vibration signal acquisition module, a displacement resistance acquisition module, and a current signal acquisition module electrically connected to a microprocessor unit. The microprocessor unit processes the monitoring information fed back from the sound signal acquisition module, vibration signal acquisition module, displacement resistance acquisition module, and current signal acquisition module and outputs it to the display module so that the operator can observe the monitoring situation online in real time.

[0060] Optionally, the microprocessor unit uses an STM32F407ZGT6 as the microprocessor. This chip supports floating-point arithmetic (FPU) and DSP instructions, and can perform FFT spectrum transformation processing. It also has 114 I / O ports, including three 12-bit AD converters, six UART serial ports, and one SDIO interface. These abundant port resources are sufficient for the centralized data receiver to connect peripherals. The minimum system circuit for the centralized data receiver is as follows: Figure 12 As shown, the system circuit includes an external RTC clock, ADC reference voltage, download interface, crystal oscillator, and reset circuit.

[0061] The input terminal of the display module is connected to the output I / O port of the microprocessor unit, such as... Figure 10 As shown, optionally, the display module uses a TJC4827K043_011 type 4.3-inch programmable touch serial screen to realize human-computer interaction, and communicates data with the receiver's microprocessor through the UART serial port.

[0062] Specifically, the sound signal acquisition module is used to collect the sound signals of the circuit breaker's opening and closing operation process and input the sound signals into the microprocessor unit. After the sound signals are acquired, the microprocessor unit starts the vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module, so that the vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module perform monitoring.

[0063] The sound signal acquisition module includes a microphone, and the output of the microphone is connected to the A / D port of the microprocessor unit input.

[0064] The microphone is installed at the lever and sends the collected sound signal to the microprocessor unit, so that the microprocessor unit sends a monitoring command.

[0065] The microprocessor unit identifies the start and end times of the sound signal relative to a preset threshold, and calculates the switching time of the circuit breaker opening and closing based on the time difference between the start and end times.

[0066] The microprocessor unit includes a first time module, a second time module, and a time calculation module arranged sequentially.

[0067] The first time module is used to obtain the start time;

[0068] Specifically, when the sound signal output by the microphone exceeds the threshold for the first time, the current timing operation state of the microprocessor unit is interrupted, and a delay period is started. When the delay period expires and the sound signal falls back below the threshold, the moment is confirmed as the start time T1.

[0069] The second time module is used to obtain the termination time;

[0070] Specifically, after the first time module confirms that the start time is valid, it starts the second monitoring of the sound signal. When the sound signal detected in the second monitoring exceeds the threshold, it interrupts the current timing operation state of the microprocessor unit and starts a delay period. When the delay period expires and the sound signal falls back below the threshold, it confirms that the time is the termination time T2.

[0071] The first time module and the second time module both use the same delay configuration module, which includes a delay configuration register and a timer, so that the two time modules have the same time confirmation standard.

[0072] The time calculation module obtains the start time T1 and the end time T2, and calculates the time difference T0 between the start time T1 and the end time T2, and uses the time difference T0 as the switching time for the circuit breaker to open and close.

[0073] like Figure 3 As shown, when the signal output by the microphone first exceeds the threshold and triggers a microprocessor interrupt, after waiting to record the next potential action time point (e.g., T1), the microprocessor does not immediately confirm it as the final T1. Instead, it starts a timer, ignoring any threshold fluctuations that may be caused by mechanical reverberation or transient interference during the next 10-20ms delay. Only after this brief delay, if the signal stably falls back below the threshold, is the initial trigger moment confirmed as the true T1. The same strategy is used to determine T2. This method effectively filters out noise interference caused by mechanical rebound before and after the switching action, making the extracted feature time points T1 and T2 more accurately correspond to the main pulse of the mechanical action, thus making the final calculated switching action time T0 = T2 - T1 more realistic and reliable.

[0074] The vibration signal acquisition module is used to collect vibration signals during the opening and closing process of the circuit breaker, and the microprocessor unit determines the execution status of the opening and closing action of the circuit breaker based on the vibration signals.

[0075] The vibration signal acquisition module includes a vibration sensor and a dual-T type 50Hz notch filter circuit. The vibration sensor is located at the lower end of the circuit breaker's pull rod. Optionally, the vibration sensor is a PVE piezoelectric film sensor, installed at the lower end of the circuit breaker's pull rod position, used to determine whether the circuit breaker's opening and closing actions are responsive. Simultaneously, it measures the point of contact or disconnection of the moving and stationary contacts in the arc-extinguishing chamber during circuit breaker operation. Combined with a linear potentiometer, the opening distance and overtravel are obtained. Based on the changes in overtravel, the wear condition of the contacts is determined. Since the moving and stationary contacts of the circuit breaker are sealed inside the arc-extinguishing chamber, the wear of the moving and stationary contacts becomes directly visible, instead of being invisible. Furthermore, based on the vibration information obtained from the vibration sensor during the circuit breaker's opening and closing process, it is determined whether the circuit breaker's opening and closing commands are executed, indirectly determining whether there are faults in the circuit breaker's opening and closing switches and actuators, and whether there is a failure to operate during opening and closing. The opening and closing action time T0 can be calculated based on the vibration duration.

[0076] As a high-performance vibration sensing device, the PVE piezoelectric thin film sensor's core characteristic lies in its ability to extremely sensitively convert mechanical vibration into corresponding electrical signal output. The sensor's output voltage changes in real time with the changes in the frequency and intensity of external vibration. This high sensitivity allows it to capture subtle vibration characteristics generated during the opening and closing of circuit breakers, providing complete and reliable raw data for subsequent mechanical condition analysis.

[0077] In practical engineering applications, vibration signal acquisition faces a common challenge: 50Hz power frequency interference. This interference primarily originates from electromagnetic field radiation from the power system and the coupling effects of various electrical devices. Because the 50Hz power frequency and its harmonic components are widespread in industrial environments, a significant 50Hz harmonic component appears in the spectrum of each acquired vibration signal. These interference signals are not only difficult to eliminate but also mask effective vibration characteristic information and severely impact the accuracy of spectrum analysis, particularly potentially obscuring low-frequency characteristic components associated with early mechanical faults.

[0078] To effectively eliminate interference, the output of the vibration sensor is connected to the input V1 of the dual-T 50Hz notch filter, and the output of the dual-T 50Hz notch filter circuit is connected to the A / D port of the microprocessor unit. The dual-T 50Hz notch filter circuit employs a symmetrical passive network structure, achieving deep attenuation at a specific 50Hz frequency through precise resistor-capacitor matching. The unique advantage of the dual-T 50Hz notch filter lies in its ability to selectively filter 50Hz power frequency interference while keeping other frequency signals largely unaffected. Its filtering characteristic curve exhibits a sharp notch characteristic at 50Hz, while maintaining a flat response in the frequency band where the useful vibration signal is located (typically several hundred Hz to several kHz). This effectively eliminates interference while preserving valuable vibration characteristic information to the maximum extent.

[0079] The design scheme, combining a PVE piezoelectric thin-film sensor and a dual-T 50Hz notch filter, fully leverages the sensor's high sensitivity and effectively overcomes environmental interference through targeted filtering, providing a reliable technical guarantee for ensuring the quality and usability of vibration signal acquisition. This hardware-level optimization design lays a solid foundation for future accurate spectrum analysis and condition diagnosis.

[0080] The displacement resistance acquisition module includes a linear potentiometer connected to the circuit breaker lever. The microprocessor unit is used to obtain the total stroke of the moving and stationary contacts of the circuit breaker arc extinguishing chamber based on the change in resistance value of the linear potentiometer when the lever moves.

[0081] The resistance value of the linear potentiometer changes linearly with the displacement stroke, and the resistance value is 0-10kΩ within the full stroke range of 0-50mm;

[0082] The lower end of the linear potentiometer is reliably fixed on the circuit breaker chassis. The slider of the linear potentiometer is connected to the lower end of the circuit breaker pull rod. As the circuit breaker opens and closes, the pull rod drives the slider of the linear potentiometer to move up and down. Based on the change in the resistance value of the linear potentiometer, the total stroke H of the moving and stationary contacts of the circuit breaker arc-extinguishing chamber can be measured.

[0083] Reference Figure 4 and Figure 5 Excessive or insufficient opening and closing speeds can impair the arc-extinguishing and breaking capacity of a circuit breaker. The opening and closing speeds can be obtained from the spindle rotation stroke signal via the opening and closing time. The total stroke is the total displacement of the moving contact, which can be subdivided into overtravel and opening distance. The dividing point between the two is called the closing point and the opening point. When the moving contact in the circuit breaker's vacuum interrupter chamber begins to move, it will contact the stationary contact after reaching the opening distance, thereby connecting the high-voltage circuit and inducing vibration. To ensure a tight connection between the moving and stationary contacts, the spring device equipped with the contacts continues to compress after the moving contact reaches the opening distance, ensuring a tight connection between the moving and stationary contacts. After the spring device is fully compressed, it will generate another strong vibration, causing the moving contact to return to the position of the total stroke.

[0084] The current signal acquisition module is used to collect the current signal of the circuit breaker operating mechanism. The operating mechanism includes an energy storage drive motor and a tripping drive electromagnet. The microprocessor unit generates a current-time curve based on the changing characteristics of the current signal over time, and determines the operating status of the energy storage drive motor and the tripping drive electromagnet based on the current-time curve.

[0085] The current signal acquisition module includes an energy storage measurement module, which is used to acquire the energy storage current signal of the energy storage drive motor coil. The microprocessor unit generates an energy storage current-time curve based on the characteristics of the energy storage current signal changing over time, and determines the operating status of the energy storage drive motor.

[0086] The energy storage measurement module includes a Hall current sensor for the energy storage drive motor coil, and the output terminal of the Hall current sensor for the energy storage drive motor coil is connected to the A / D port of the microprocessor unit.

[0087] The Hall current sensor for the energy storage drive motor coil uses a 5A rated current through-hole Hall current transformer to measure the current of the energy storage drive motor coil and plot the current-time curve. Based on the current-time curve of the energy storage drive motor coil, the complete process of the operating mechanism can be intuitively reflected, and indirectly, it can be reflected whether there are phenomena such as jamming or wire breakage in the operating mechanism.

[0088] In electric spring operating mechanisms, the energy storage drive motor is responsible for providing energy to the closing spring. As a crucial component of the operating mechanism, any malfunction of the energy storage drive motor will prevent the opening and closing operations from being completed. When the transmission mechanism jams, the energy storage drive motor will be powered on but unable to operate normally, increasing the risk of the motor coil burning out and threatening the safe operation of the equipment. Therefore, monitoring and diagnosing the current signal of the energy storage drive motor is essential to prevent its failure. The theoretical curve of the drive current of the energy storage drive motor is shown below. Figure 6 As shown.

[0089] Specifically, in During this period, the DC energy storage drive motor is When the power is constantly applied, the current rises rapidly and... Peak current is obtained at all times. This refers to the starting current of the motor. If the transmission mechanism malfunctions and seizes up during this stage, the energy storage drive motor is essentially in a short-circuit state between resistance and inductance. Prolonged high current flow will generate heat, causing the motor to burn out. During this period, the energy storage drive motor starts to rotate, and the current drops rapidly to ;exist During this period, the energy storage drive motor continues to rotate, the energy storage spring does not change significantly, and the current of the energy storage drive motor remains essentially constant. ;exist During this period, the shape of the energy storage spring changes significantly, it begins to stretch, the load torque of the energy storage drive motor increases, and the current increases to [a certain value]. ;exist During this period, the energy storage spring continues to stretch, the motor load torque decreases, and the current begins to decrease. When energy storage is complete, the energy storage drive motor is de-energized. The time is 0.

[0090] The sensor's through-hole structure facilitates online detection without damaging the coil circuit, allowing it to acquire the current signal when the coil is operating.

[0091] The current signal acquisition module also includes an electromagnetic measurement module, which is used to collect the electromagnetic current of the electromagnet coil driving the opening and closing. The microprocessor unit generates an electromagnetic current-time curve based on the characteristics of the electromagnetic current signal changing with time, and determines the operating status of the opening and closing action.

[0092] The electromagnetic measurement module includes a Hall current sensor for the opening and closing drive electromagnet coil, and the output terminal of the Hall current sensor for the opening and closing drive electromagnet coil is connected to the A / D port of the microprocessor unit input terminal.

[0093] The Hall current sensor of the opening and closing drive electromagnet coil sends the collected continuous operating time t5 of the opening and closing drive electromagnet coil to the microprocessor unit, and the average opening and closing speed of the circuit breaker is calculated as follows:

[0094] V=2H / (T0+t5);

[0095] In the formula, H is the total stroke of the moving and stationary contacts of the circuit breaker's arc-extinguishing chamber.

[0096] The Hall current sensor for the opening and closing drive electromagnet coil uses a 5A rated current through-hole Hall current transformer to measure the current of the opening and closing drive electromagnet coil, establishing an electromagnetic current-time curve. Based on the electromagnet coil current-time curve, the complete process of opening and closing operation can be intuitively reflected. By calculating the continuous working time of the electromagnet coil current, the opening and closing operation time t5 of the circuit breaker can be obtained. The average value of the circuit breaker opening and closing operation time t5 obtained by the current curve method and the circuit breaker opening and closing operation time T0 obtained by the vibration method is used as the time to calculate the average speed of the circuit breaker opening and closing operation. Then, based on the measured total stroke H of the moving and stationary contacts of the circuit breaker arc extinguishing chamber, the average opening and closing speed is obtained. The average opening and closing speed is an important indicator reflecting the performance of the circuit breaker; it should not be too high or too low.

[0097] After the opening and closing command is initiated, the opening and closing drive electromagnet coil is energized to generate electromagnetic force to drive the iron core and overcome the elastic force of the spring and the frictional resistance caused by friction, resulting in linear motion. After the iron core hits the limit switch of the opening and closing, it will cause the opening and closing energy storage spring to release energy to drive the transmission mechanism, thereby realizing the separation of the moving and stationary contacts in the arc extinguishing chamber of the load switch of the gas-filled ring main unit.

[0098] When the opening and closing drive electromagnet coil is working, it is equivalent to an inductive load, so its equivalent circuit is as follows: Figure 7 As shown, its loop voltage satisfies:

[0099] (1);

[0100] (2);

[0101] In equation (2), i is the excitation coil current and R is the excitation coil resistance. Then the voltage across the inductor L is:

[0102] (3);

[0103] When the magnetic flux of the iron core is unsaturated, the excitation coil acts as a linear element, and the self-induction chain of the inductor coil... for:

[0104] (4);

[0105] The combined equations (3) and (4) are:

[0106] (5);

[0107] The current in inductor L is not affected by the current i flowing through the excitation coil, but rather by the change in the thickness of the air gap between the inductor and the iron core, i.e., by the displacement x of the iron core. Therefore, the loop voltage of the inductor is:

[0108] (6);

[0109] The theoretical curve of the current signal of the electromagnet coil driving the opening and closing circuit is as follows: Figure 8 As shown.

[0110] Depend on Figure 8 It can be seen that, in ~ When the electromagnet coil is energized, the current increases, and the iron core experiences both spring force and frictional force. At this point, the resistance force on the iron core equals the electromagnetic force, and it remains stationary. Meanwhile, the inductance... Minimum current:

[0111] (7);

[0112] The current increase rate is:

[0113] (8);

[0114] As the current further increases, until Its value reaches at time At this point, the electromagnetic force applied to the iron core exceeds the resistance caused by friction, and the iron core begins to move in a straight line. ~ During this period, after the iron core moves, its velocity v gradually increases, and as the displacement x of the iron core changes continuously, its inductance also changes accordingly. In this dynamic process, the equation of the circuit is expressed as:

[0115] (9);

[0116] In equation (9), as the speed increases, This manifests as a back electromotive force, which causes the current in the electromagnet coil to decrease, when it reaches... At time t, the value of the current in the electromagnet coil is At this moment, the iron core collides with the locking mechanism for opening and closing the circuit breaker. ~ In the interim, assuming the iron core's instantaneous velocity decreases to 0 due to the collision, ignore... Due to the influence of this, and because it needs to drive the rotation of the subsequent mechanism, the current in the electromagnet coil at this time is:

[0117] (10);

[0118] In equation (10), i2 is the instantaneous value of the current in the electromagnet coil;

[0119] exist At time 1, the current increases to Electromagnetic force drives the iron core to move, causing the opening and closing switches to disengage, and the energy-storing spring releases energy to complete the opening and closing operation. Meanwhile... ~ During this period, the coil core almost reaches its maximum displacement, at which point the current in the electromagnet coil is equivalent to... The current essentially no longer changes; ~ In between, due to Once the load switch is opened or closed, the electromagnet coil will be disconnected from the power supply circuit or the preset power supply time will be reached, stopping the power supply and causing the current to drop sharply to 0.

[0120] The online monitoring device also includes a power supply unit, which includes an open-type CT power supply module;

[0121] The open-type CT power supply module includes a power supply CT submodule and a power conversion submodule. The power supply CT submodule is installed on the cable in the cable room to obtain electrical energy from the cable and outputs alternating voltage. The power conversion submodule is electrically connected to the power supply CT submodule and is used to convert the alternating voltage into DC voltage and supply power to the microprocessor unit.

[0122] The power conversion submodule includes a power supply circuit, a stabilization circuit, and a protection circuit;

[0123] The power supply circuit includes a rectifier bridge D1, a resistor R4, an electrolytic capacitor C10, a tantalum capacitor C11, a Zener diode D3, a tantalum capacitor C12, a voltage monitoring chip S80848, a diode D4, a current-limiting resistor R6, a ceramic capacitor C13, and a MOSFET Q1.

[0124] Specifically, the rectifier bridge D1, the electrolytic capacitor C10, and the tantalum capacitor C11 are connected in parallel in sequence. The resistor R4 is connected in series between the rectifier bridge D1 and the electrolytic capacitor C10. The Zener diode D3 is connected in series with the tantalum capacitor C12 and then in parallel with the tantalum capacitor C11. The input terminal of the voltage monitoring chip S80848 is connected in series with the Zener diode D3 and the tantalum capacitor C12. The output terminal is connected in series with the diode D4, the current limiting resistor R6, and the MOSFET Q1. The drain and source of the MOSFET Q1 are connected in parallel with the ceramic capacitor C13.

[0125] The stabilizing circuit includes a diode D5 and a resistor R5. One end of the diode D5 is connected in series between the diode D4 and the current-limiting resistor R6, and the other end is connected in series with the resistor R5.

[0126] The protection circuit includes a high-voltage capacitor C8, a high-voltage capacitor C9, a bidirectional TVS transient suppression transistor D2, a resistor R7, and a resistor R8. The high-voltage capacitor C8 is connected in parallel with the rectifier bridge D1, the high-voltage capacitor C9 is connected in parallel with the bidirectional TVS transient suppression transistor D2, and the resistors R7 and R8 are connected in series with the resistor R4.

[0127] like Figure 13 As shown, the circuit converts the output voltage from the secondary side of the power-taking current transformer (CT) into DC voltage through rectifier bridge D1. The DC voltage then charges the large-capacity electrolytic capacitor C10 and tantalum capacitor C11 after passing through resistor R4. When the voltage across electrolytic capacitor C10 and tantalum capacitor C11 increases to the reverse breakdown threshold of Zener diode D3, Zener diode D3 immediately conducts, causing electrolytic capacitor C10 and tantalum capacitor C11 to charge tantalum capacitor C12. Once the voltage to ground on tantalum capacitor C12 reaches the gate voltage of voltage monitoring chip S80848, the voltage monitoring chip S80848 will charge the parasitic capacitance of MOSFET Q1 through its OUT pin, using diode D4 and current-limiting resistor R6. Once the gate voltage of MOSFET Q1 reaches the 3V threshold, MOSFET Q1 conducts, providing power to the STM32F407ZGT6 microprocessor. After the STM32 is powered on, it controls the I / O port to a high level, charging the MOSFET Q1 through diodes D5 and R6. During this process, diodes D4 and D5 form an OR gate. When the STM32 chip is powered on, the release of front-end energy reduces the voltage to ground on the tantalum capacitor C12. Once this voltage drops below the gate voltage of the voltage monitoring chip S80848, the voltage monitoring chip S80848 will stop operating, causing the MOSFET Q1 to turn off, thus affecting the supply of working power to the online monitoring device. However, through the setting of the stabilization circuit, even when the voltage monitoring chip S80848 stops operating, the MOSFET Q1 can still be forcibly turned on through diode D5 to ensure the stability of the power supply. To prevent instantaneous overvoltage of the MOSFET Q1, a ceramic capacitor C13 is connected in parallel across its two ends.

[0128] Meanwhile, in the event of a short-term fault in the three-phase cable, the large current generated by the fault can be reduced to mitigate the power surge to the online monitoring device through resistors R4, high-voltage capacitors C8 and C9, and a bidirectional TVS transient suppression transistor D2, thus providing protection and limiting charging current. Resistor R5 can be used to force a low voltage level, preventing the MOSFET Q1 from prematurely turning on due to impedance mismatch during charging, which would affect energy collection. Resistors R7 and R8 are used in series for voltage division. When the voltage to ground of tantalum capacitor C12, acquired by the microprocessor's ADC pin, is lower than 5V, the control level is adjusted to pull resistor R5 low, causing the voltage monitoring chip S80848 and MOSFET Q1 to turn off, stopping the STM32 and allowing energy collection to continue. Simultaneously, the turn-off of MOSFET Q1 de-energizes subsequent circuits, eliminating power device losses and improving the low-power efficiency of the online monitoring device.

[0129] Furthermore, the online monitoring device also includes a communication module, a clock module, an address selection module, and a storage module.

[0130] The clock module output is connected to the microprocessor unit input I / O port; the clock module uses the DS1302 chip, which is used to record and monitor the time.

[0131] The input terminal of the communication module is connected to the communication interface corresponding to the microprocessor unit; such as Figure 9 As shown, the communication module adopts the RSM485PHT communication module. This model of RS485 transceiver has good electromagnetic radiation suppression characteristics and strong anti-electromagnetic interference performance, and can stably support the operation of up to 128 nodes.

[0132] The output of the address selection module is connected to the I / O port of the microprocessor unit; the address selection module uses a 10-bit DIP switch to set the device address, making it easy to distinguish which measuring device it is.

[0133] The input terminal of the storage module is connected to the output I / O port of the microprocessor unit, such as... Figure 11 As shown, the storage module uses a TF card to store the monitoring parameters.

[0134] Example 2: This example discloses an online monitoring method for the mechanical characteristics of a circuit breaker. The online monitoring device described in Example 1 is used to achieve online monitoring of the mechanical characteristics of the circuit breaker. The method includes the following steps:

[0135] Acquire the sound signals of the circuit breaker during the opening and closing process;

[0136] Acquire the sound signals of the circuit breaker during the opening and closing process;

[0137] Based on the sound signal, the microprocessor unit activates the vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module to execute online monitoring commands on the mechanical characteristics of the circuit breaker.

[0138] The vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module feed back various mechanical characteristic data during the monitoring process to the microprocessor unit;

[0139] The microprocessor unit processes and analyzes the various mechanical characteristic data to complete the online monitoring of the circuit breaker's mechanical characteristics.

[0140] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0141] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and all such equivalent transformations fall within the protection scope of the present invention.

Claims

1. An online monitoring device for the mechanical characteristics of a circuit breaker, characterized in that: Includes a monitoring signal acquisition unit and a microprocessor unit; The monitoring signal acquisition unit includes: The sound signal acquisition module is used to collect the sound signals of the circuit breaker's opening and closing operations. The vibration signal acquisition module is used to collect vibration signals during the opening and closing process of the circuit breaker; The displacement resistance acquisition module is used to collect the displacement resistance value of the circuit breaker rod during the opening and closing process of the circuit breaker. The current signal acquisition module is used to acquire the current signal of the circuit breaker operating mechanism; The microprocessor unit is configured as follows: In response to receiving the sound signal, the vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module are activated. Based on the acquired vibration signal, the execution status of the circuit breaker's opening and closing actions is determined; Based on the change in the obtained displacement resistance value, the total stroke of the moving and stationary contacts of the circuit breaker arc extinguishing chamber is obtained. Based on the characteristics of the current signal changing over time, a current-time curve is generated, and the operating status of the circuit breaker operating mechanism is determined according to the current-time curve.

2. The online monitoring device for the mechanical characteristics of a circuit breaker according to claim 1, characterized in that: The sound signal acquisition module includes a microphone; The microphone is installed at the lever and sends the collected sound signal to the microprocessor unit, so that the microprocessor unit sends a monitoring command; The microprocessor unit identifies the start and end times of the sound signal relative to a preset threshold, and calculates the switching time of the circuit breaker opening and closing based on the time difference between the start and end times.

3. The online monitoring device for the mechanical characteristics of a circuit breaker according to claim 2, characterized in that: The microprocessor unit includes a first time module, a second time module, and a time calculation module arranged sequentially. The first time module is used to obtain the start time, the second time module is used to obtain the end time, and the time calculation module is used to calculate the time difference.

4. The online monitoring device and method for the mechanical characteristics of circuit breakers according to claim 1, characterized in that: The vibration signal acquisition module includes a vibration sensor and a dual-T 50Hz notch filter circuit, and the vibration sensor is installed at the pull rod. The output terminal of the vibration sensor is connected to the input terminal V1 of the double-T type 50Hz notch filter.

5. The online monitoring device for the mechanical characteristics of a circuit breaker according to claim 1, characterized in that: The displacement resistance acquisition module includes a linear potentiometer connected to the pull rod. The microprocessor unit obtains the total stroke of the moving and stationary contacts of the circuit breaker arc extinguishing chamber based on the change in the resistance value of the linear potentiometer caused by the movement of the pull rod. The resistance value of the linear potentiometer changes linearly with the displacement stroke, and the resistance value is 0-10kΩ within the full stroke range of 0-50mm.

6. The online monitoring device and method for the mechanical characteristics of circuit breakers according to claim 1, characterized in that: The current signal acquisition module includes an energy storage measurement module, and the operating mechanism includes an energy storage drive motor. The energy storage measurement module is used to acquire the energy storage current signal of the energy storage drive motor coil. The microprocessor unit generates an energy storage current-time curve based on the characteristics of the energy storage current signal changing over time, and determines the operating status of the energy storage drive motor. The energy storage measurement module includes a Hall current sensor for the energy storage drive motor coil.

7. The online monitoring device for the mechanical characteristics of a circuit breaker according to claim 1, characterized in that: The current signal acquisition module also includes an electromagnetic measurement module, and the operating mechanism also includes a circuit breaker drive electromagnet. The electromagnetic measurement module is used to acquire the electromagnetic current signal of the circuit breaker drive electromagnet coil. The microprocessor unit generates an electromagnetic current-time curve based on the characteristics of the electromagnetic current signal changing with time, and determines the operating status of the circuit breaker action. The electromagnetic measurement module includes a Hall current sensor for the electromagnet coil used for opening and closing the circuit breaker.

8. The online monitoring device for the mechanical characteristics of a circuit breaker according to claim 1, characterized in that: It also includes a power supply unit, which includes an open-type CT power supply module; The open-type CT power supply module includes: The power-collecting CT submodule acquires electrical energy from the cable and outputs alternating voltage; The power conversion submodule is electrically connected to the power CT submodule and is used to convert the alternating voltage into a direct current voltage and supply power to the microprocessor unit.

9. The online monitoring device for the mechanical characteristics of a circuit breaker according to claim 8, characterized in that: The power conversion submodule includes a power supply circuit, a stabilization circuit, and a protection circuit; The power supply circuit includes a rectifier bridge D1, a resistor R4, an electrolytic capacitor C10, a tantalum capacitor C11, a Zener diode D3, a tantalum capacitor C12, a voltage monitoring chip S80848, a diode D4, a current-limiting resistor R6, a ceramic capacitor C13, and a MOSFET Q1. The rectifier bridge D1, the electrolytic capacitor C10, and the tantalum capacitor C11 are connected in parallel. The resistor R4 is connected in series between the rectifier bridge D1 and the electrolytic capacitor C10. The Zener diode D3 is connected in series with the tantalum capacitor C12 and then in parallel with the tantalum capacitor C11. The input terminal of the voltage monitoring chip S80848 is connected in series with the Zener diode D3 and the tantalum capacitor C12. The output terminal is connected in series with the diode D4, the current-limiting resistor R6, and the MOSFET Q1. The drain and source of the MOSFET Q1 are connected in parallel with the ceramic capacitor C13. The stabilizing circuit includes a diode D5 and a resistor R5. One end of the diode D5 is connected in series between the diode D4 and the current-limiting resistor R6, and the other end is connected in series with the resistor R5. The protection circuit includes a high-voltage capacitor C8, a high-voltage capacitor C9, a bidirectional TVS transient suppression transistor D2, a resistor R7, and a resistor R8. The high-voltage capacitor C8 is connected in parallel with the rectifier bridge D1, the high-voltage capacitor C9 is connected in parallel with the bidirectional TVS transient suppression transistor D2, and the resistors R7 and R8 are connected in series with the resistor R4.

10. A method for online monitoring of the mechanical characteristics of a circuit breaker, characterized in that: The method using the online monitoring device according to any one of claims 1-9 includes the following steps: Acquire the sound signals of the circuit breaker during the opening and closing process; Based on the sound signal, the microprocessor unit activates the vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module to execute online monitoring commands on the mechanical characteristics of the circuit breaker. The vibration signal acquisition module, the displacement resistance acquisition module, and the current signal acquisition module feed back various mechanical characteristic data during the monitoring process to the microprocessor unit; The microprocessor unit processes and analyzes the various mechanical characteristic data to complete the online monitoring of the circuit breaker's mechanical characteristics.

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