A grounding electromagnetic lock

Abstract

This invention provides a grounding electromagnetic lock, comprising a housing, an electromagnetic actuation component, and a control circuit board. Both the electromagnetic actuation component and the control circuit board are housed within the housing. The lock also includes a connector and a grounding rod fixing mechanism. The grounding rod fixing mechanism includes a connecting rod body, a fixing nut, a first gear, and a second gear. The fixing nut is located on the connecting rod body. A universal connector is detachably provided at the bottom of the connecting rod body for connecting the grounding rod. When the connecting rod body is inserted into the connector, the first and second fixing handles are used to tightly contact the bottom surface of the fixing nut after rotation. This invention fully considers interference types and volume requirements, and specifically designs each component of the electromagnetic lock to prevent electromagnetic interference. This ensures that the entire chain of wireless signal power supply, acquisition, processing, and transmission can effectively cope with switch operation surges, power frequency magnetic fields, and high-frequency radiation within substations, guaranteeing the reliability and stability of wireless signal transmission.

Description

Technical Field

[0001] This invention belongs to the field of grounding electromagnetic lock technology, specifically relating to improvements in the ease of installation of grounding electromagnetic locks. Background Technology

[0002] Grounding electromagnetic locks are widely used devices in the maintenance of substations and high-voltage equipment. During operation, the operator inserts the grounding rod head into the grounding electromagnetic lock to ensure that the grounding rod or grounding wire is used at the correct time, avoiding dangerous operations such as hanging the grounding wire while it is energized or closing the circuit with the grounding wire connected, and preventing safety accidents caused by misoperation in the power system.

[0003] Existing grounding electromagnetic locks have the following problems in practical use: (1) When maintenance personnel are inspecting the grounding electromagnetic lock, because there are many lock body manufacturers and the grounding rod heads of different manufacturers cannot be interchanged, they need to carry a large number of grounding rod heads of different shapes and sizes in order to operate smoothly. If they mistakenly take or take too few grounding rod heads, they need to return to the equipment room to take them again, which increases maintenance time and reduces work efficiency.

[0004] (2) When installing, repairing, or replacing grounding electromagnetic locks, a large number of signal lines need to be laid out and connected. On the one hand, there is a risk of misconnection or incorrect connection. On the other hand, it is also easy to cause DC grounding faults, which pose safety hazards. If wireless communication is simply introduced to replace wired communication, due to the special nature of the usage scenario, it is necessary to face a series of interference sources such as switch operation interference, lightning overvoltage interference, power frequency electromagnetic field interference, reactor and capacitor bank interference, and power electronic equipment interference. This can easily cause a series of problems such as power supply damage, interface chip burnout, control component crashes, abnormal resets, relay malfunctions, and protection malfunctions. There is no complete and reliable wireless signal transmission scheme for grounding electromagnetic locks in the existing technology.

[0005] The above problems make the installation and use of existing grounding electromagnetic locks cumbersome, and there is an urgent need to design a grounding electromagnetic lock that is easy to install and has reliable communication. Summary of the Invention

[0006] To address the above technical problems, this invention provides a grounding electromagnetic lock that is compatible with various types of grounding rod heads and considers signal interference issues throughout the entire chain, ensuring the reliability of signal transmission of the grounding electromagnetic lock.

[0007] The technical solution of the present invention is: a grounding electromagnetic lock, comprising a housing, an electromagnetic actuation component, and a control circuit board, wherein the electromagnetic actuation component and the control circuit board are both disposed within the housing, the electromagnetic actuation component is electrically connected to the control circuit board, and the lock further comprises a connector and a grounding rod fixing mechanism; the connector is electrically connected to the control circuit board. The grounding rod fixing mechanism includes a connecting rod body, a fixing nut, a first gear, and a second gear. The fixing nut is located on the connecting rod body. A universal connector is detachably provided at the bottom of the connecting rod body for connecting the grounding rod. The first gear and the second gear are rotatably located inside the outer shell and mesh with each other. A first fixing handle is located below the first gear, and a second fixing handle is located below the second gear. A first elastic component is sleeved on the first fixing handle between the first gear and the outer shell. A first stop is provided on the first fixing handle, which is used to press tightly against the outer wall of the outer shell when pulled by the first elastic component. A second elastic component is fitted onto the second fixed handle between the second gear and the housing. The second fixed handle is provided with a second stop, which is used to press tightly against the outer wall of the housing when pulled by the second elastic component. With the connecting rod inserted into the connector, the first and second fixing handles are used to fit tightly against the bottom surface of the fixing nut after rotation.

[0008] Preferably, the control circuit board includes a microprocessor, a power supply circuit, an insertion detection circuit, a wireless communication interface, and an electromagnetic detection interface, and the microprocessor is electrically connected to the power supply circuit, the insertion detection circuit, the wireless communication interface, and the electromagnetic detection interface, respectively. The microprocessor is used to execute instructions and process data; the power supply circuit is used to connect to a power source and supply power to the components; the insertion detection circuit is used to detect whether the connecting rod is inserted; the wireless communication interface is used to connect to a wireless communication component; the electromagnetic detection interface is used to connect to an electromagnetic detection component. The connector is located inside the housing, and the housing has a corresponding inlet. The connector has several contacts inside, and all contacts are electrically connected to the insertion detection circuit. The inlet is used to connect the rod body to the connector. The control circuit board is also equipped with a switch for the electromagnetic actuator, and the housing is equipped with a button corresponding to the switch.

[0009] Preferably, the electromagnetic detection component includes a magnetoresistive sensor, a calibration drive circuit, a signal amplification and filtering conditioning circuit, and an interface protection circuit, wherein the magnetoresistive sensor is connected in series with the calibration drive circuit, the signal amplification and filtering conditioning circuit, and the interface protection circuit. The calibration drive circuit is used to calibrate the signal, the signal amplification and filtering conditioning circuit is used to amplify and purify the signal, and the interface protection circuit is used to prevent power surges.

[0010] Preferably, the wireless communication interface is connected to the LoRa module, and a Schmitt trigger is connected in series between the wireless communication interface and the microprocessor. The LoRa module and the Schmitt trigger have independent power inputs. Several grounded high-frequency filter capacitors are connected in parallel between the wireless communication interface and the microprocessor.

[0011] Preferably, the control circuit board is further provided with a plurality of indicator units, and the housing is provided with a plurality of clearance holes corresponding to the indicator units.

[0012] Preferably, the control circuit board is equipped with a wired communication circuit interface and an early warning unit.

[0013] Preferably, the electromagnetic actuator is further provided with a manual unlocking mechanism, the unlocking port of which is located outside the housing.

[0014] Preferably, the power supply circuit includes an EMI filter circuit consisting of an X capacitor, a common-mode inductor, and several Y capacitors. The EMI filter circuit is connected in series between the microcontroller and the power supply port and is used to suppress electromagnetic interference.

[0015] Preferably, it also includes a grounding stake, one end of which is connected to the plug connector, and the other end of which is used for grounding.

[0016] Preferably, the telescopic iron core of the electromagnetic actuation component is located above the second gear, and the second gear is provided with a locking hole that matches the telescopic iron core; the locking hole is used to prevent the second gear from rotating. The telescopic iron core is fitted with a third elastic component, one end of which abuts against the telescopic iron core and the other end of which abuts against the mounting plate of the electromagnetic actuation component.

[0017] The beneficial effects of this invention are: the use of a gear spring clamping device to fix the connecting rod with a universal connector can adapt to grounding rod heads of different shapes and sizes, which facilitates operation and maintenance, reduces maintenance time, and improves work efficiency.

[0018] By adopting wireless signal transmission, the occurrence of signal line misconnection, incorrect connection, and DC grounding fault during on-site installation is fundamentally eliminated. In terms of structure, the power supply circuit adopts an EMI filter circuit composed of X capacitors, common-mode inductors, and several Y capacitors. The microprocessor section adopts a combination of multi-stage ferrite beads and capacitor filters. The electromagnetic detection section adopts a combination of ferrite beads, capacitors, and active filters. The grounding rod detection section adopts a combination of RC filters and Schmitt triggers. The wireless signal transmission section adopts a combination of Schmitt triggers, multi-stage filters, and ferrite beads. The status indicator light section adopts a combination of TVS diodes and RC filters. Taking into full account the types of interference and the volume occupied, each component of the electromagnetic lock is specifically designed to prevent electromagnetic interference. This ensures that the entire link of power supply, acquisition, processing, and transmission of wireless signals can effectively cope with the surges of switch operations, power frequency magnetic fields, and high-frequency radiation in the substation, guaranteeing the accuracy of wireless signal acquisition and processing, as well as the reliability and stability of transmission. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 2 This is a bottom view of the grounding electromagnetic lock of the present invention. Figure 3 This is a schematic diagram of the internal structure of the present invention. Figure 4 This is a schematic diagram of the structure with the grounding rod inserted. Figure 5 This is a circuit diagram of the control section in the embodiment. Figure 6 This is a circuit diagram of the power supply section in the embodiment. Figure 7 In this embodiment, the grounding stake head is connected to the detection line. Figure 8 This is a circuit diagram of the wireless communication section in the embodiment. Figure 9 This is a circuit diagram of the 485 communication interface section in the embodiment. Figure 10 This is a circuit diagram of the electromagnetic detection section in the embodiment. Figure 11 This is a circuit diagram of the status indication in the embodiment. Figure 12 This is a circuit diagram of the upgrade interface in the embodiment. In the diagram, 1 is the outer casing, 11 is the button, 12 is the limit stop, 2 is the electromagnetic actuator, 21 is the telescopic iron core, 22 is the manual unlocking mechanism, 23 is the third elastic component, 3 is the control circuit board, 31 is the switch, 32 is the status indicator light, 4 is the connector, 5 is the grounding rod fixing mechanism, 51 is the connecting rod body, 52 is the fixing nut, 53 is the first gear, 54 is the second gear, 541 is the locking hole, 55 is the universal connector, 56 is the first fixed handle, 561 is the first stop, 57 is the second fixed handle, 571 is the second stop, 58 is the first elastic component, and 59 is the second elastic component. 6 is the grounding stake, 7 is the waterproof cover, and 8 is the power connector. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "vertical," "horizontal," "inner," "outer," "front," and "back," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] Figures 1 to 4 The middle is a grounding electromagnetic lock, including a shell 1, an electromagnetic actuation component 2 and a control circuit board 3. In this embodiment, the control circuit board 3 is connected to the mains power through a power supply 8. This is a conventional technology, and the specific structure will not be described in detail. The electromagnetic actuation component 2 and the control circuit board 3 are both located inside the shell 1. The electromagnetic actuation component 2 and the control circuit board 3 are electrically connected. It also includes a connector 4 and a grounding rod fixing mechanism 5. The grounding rod fixing mechanism 5 includes a connecting rod body 51, a fixing nut 52, a first gear 53, and a second gear 54. The fixing nut 52 is disposed on the connecting rod body 51. The bottom of the connecting rod body 51 is detachably connected to a universal connector 55 via a threaded connection. The universal connector 55 is used to connect the grounding rod. The first gear 52 and the second gear 53 are rotatably disposed inside the outer casing 1. The first gear 52 and the second gear 53 mesh. A first fixing handle 56 is disposed below the first gear 52. In this embodiment, the first fixing handle 56 is provided with a push rod for easy pushing. A second fixing handle 57 is disposed below the second gear 54. A first elastic component 58 is sleeved on the first fixing handle 56 between the first gear 54 and the inner wall of the outer casing 1. A first stop 561 is provided on the first fixing handle 56. The first stop 561 is tightly attached to the outer wall of the outer casing 1 under the pull of the first elastic component 58. A limiting stop 12 is also provided on the outer casing 1. In this embodiment, the first elastic component 58 is a spring.

[0023] A second elastic member 59 is sleeved on the second fixed handle 57 between the second gear 54 and the inner wall of the outer casing 1. The second fixed handle 57 is provided with a second stop 571, which is tightly pressed against the outer wall of the outer casing 1 under the pull of the second elastic member 59. The telescopic iron core 21 of the electromagnetic actuation assembly 2 is located above the second gear 54. The second gear 54 is provided with a locking hole 541 that matches the telescopic iron core 21. In this embodiment, the second elastic member 59 is a spring.

[0024] The connector 4 is located inside the housing 1, and the housing 1 has a corresponding inlet. In this embodiment, the housing is also provided with a waterproof cover 7, which is used to seal the connector 4 in the idle state to prevent moisture from entering. The connector 4 has several contacts, all of which are electrically connected to the control circuit board 3.

[0025] With the connecting rod 51 inserted into the connector 4, the first fixing handle 56 and the second fixing handle 57 rotate and come into close contact with the bottom surface of the fixing nut 52. Under the push of the spring, the two fixing handles can firmly press against the fixing nut 52. Then, press the button 11 to telescopically insert the iron core 21 into the locking hole 541, so that the connecting rod 51 is firmly fixed in the connector 4. Next, install the universal connector 55 on the connecting rod 51. The universal connector 55 can be matched with various types of grounding rods, so that the lock body can also be matched with different grounding rods. Even if a special type of grounding rod appears, only a small detachable connector needs to be carried, which greatly improves the work efficiency.

[0026] The control circuit board 3 is equipped with a microprocessor, a power supply circuit, an insertion detection circuit, a wireless communication interface, and an electromagnetic detection interface. The microprocessor is electrically connected to the power supply circuit, the insertion detection circuit, the wireless communication interface, and the electromagnetic detection interface, respectively. The wireless communication interface is electrically connected to the wireless communication component, and the electromagnetic detection interface is electrically connected to the electromagnetic detection component. The control circuit board 3 is also equipped with a switch for the electromagnetic actuation component, and the housing is equipped with a button corresponding to the switch.

[0027] The control circuit board 3 is also equipped with a switch 31 for the electromagnetic actuator 2, and the housing 1 is equipped with a button 11 corresponding to the switch 31.

[0028] The electromagnetic detection component includes a magnetoresistive sensor, a calibration drive circuit, a signal amplification and filtering conditioning circuit, and an interface protection circuit. The magnetoresistive sensor and the calibration drive circuit are electrically connected, and the magnetoresistive sensor is connected in series with the calibration drive circuit, the signal amplification and filtering conditioning circuit, and the interface protection circuit.

[0029] The control circuit board 3 is also provided with 3 indicator units, namely the unit status indicator light 32 in this embodiment, and the housing 1 is provided with several clearance holes corresponding to the status indicator light 32.

[0030] The control circuit board 3 is equipped with a wired communication circuit interface and a buzzer. If the electromagnetic detection component detects interference exceeding the threshold, it triggers the buzzer alarm and connects to the wired communication circuit for communication.

[0031] The wireless communication component sends information to relevant devices (such as mobile terminals and the main control room) via wireless signals. At the same time, the corresponding status indicator light 32 illuminates to remind on-site personnel that the action signal has been received. No signal cable is required, which eliminates the possibility of incorrect or faulty signal cable connection during on-site installation, as well as DC grounding faults.

[0032] The electromagnetic actuator 2 is also equipped with a manual unlocking mechanism 22, the unlocking port of which is located outside the housing 1. The manual unlocking mechanism 22 has a conventional structure and will not be described in detail.

[0033] The grounding electromagnetic lock also includes a grounding stake 6, one end of which is connected to the connector 4, and the other end of which is used to connect to the grounding equipment.

[0034] The telescopic core 21 is fitted with a third elastic component 23. One end of the third elastic component 23 abuts against the telescopic core 21, and the other end abuts against the mounting plate of the electromagnetic actuator 2. This allows the telescopic core 21 to be stably inserted into the locking hole 54 even when the power is off. In this embodiment, the third elastic component 23 is a spring.

[0035] See Figure 5In this embodiment, the microprocessor uses an STM32F103C8T6 as the system controller. Based on the standard minimum system, the power supply filtering, reset management, and anti-interference design are enhanced to ensure stable operation in complex electromagnetic environments. Figure 5 Other unused interfaces are also shown.

[0036] The power supply and filtering system employs multi-stage power supply filtering: All VDD pins are connected to a π-type filter network consisting of ferrite beads L4, L5, L8, L10 and capacitors to effectively suppress high-frequency interference and power supply noise.

[0037] The analog power supply VDDA is filtered separately by ferrite bead L7 and capacitors C40 / C41 to ensure ADC sampling accuracy.

[0038] VBAT power supply: The VBAT pin is powered by 3V3 through the L4 ferrite bead, which is used to maintain the RTC and backup registers when the main power is off.

[0039] The reset management uses a dedicated reset chip U12: model: IMP809REUR / T, which monitors the 3V3 power supply voltage. When the voltage is lower than the reset threshold, a reliable low-level reset signal is generated to ensure that the system can reset stably when the power supply fluctuates, thus solving the problem of program crashes caused by power fluctuations.

[0040] For substation scenarios, multi-stage ferrite beads and capacitor filters are used to solve high-frequency interference and surges on power lines, effectively dealing with lightning strikes, switching operation surges, power frequency magnetic fields, and high-frequency radiation within the substation.

[0041] See Figure 6 The power supply line hardware in this embodiment is as follows: Fuse (FU1): 2A / 250VAC slow-blow fuse, used as primary overcurrent protection to prevent serious faults caused by short circuits in subsequent stages.

[0042] Surge suppression (MOV1): 14D561K varistor, used to absorb grid surge voltage and protect downstream circuits from instantaneous high voltage impacts caused by lightning strikes or switching operations.

[0043] Discharge resistor (R12): 1MΩ resistor, which discharges the X capacitor after power is off to prevent the plug from becoming live, in accordance with safety regulations.

[0044] X capacitor (X2): 0.22μF / 275Vac capacitor, used to filter out differential mode interference.

[0045] Common mode inductor (U3): 3mH common mode inductor, which, when used in conjunction with a Y capacitor, effectively suppresses common mode interference and improves EMC performance.

[0046] Y capacitors (X3, C16, C19): 0.1μF / 275Vac and 472M / 250 / 400V capacitors, connected between the primary and ground, are used to discharge common-mode interference while meeting safety requirements.

[0047] Power Module (U1,FA6-220S): This is an AC-DC isolated power module that blocks the direct electrical connection between the primary side (AC220V) and the secondary side (DC5V), eliminating common-mode interference caused by the potential difference between the two places (ground loop), effectively suppressing spike pulses, harmonics and common-mode noise in the power grid, and providing a "clean" power supply for the subsequent circuits.

[0048] Self-resetting fuse (F1): 200mA self-resetting fuse, used as secondary overcurrent protection, automatically disconnects in case of overload and can be restored to conduction after the fault is cleared.

[0049] Output filtering (C17, C18): 330μF / 25V electrolytic capacitor and 0.1μF ceramic capacitor, used to smooth the 5V output voltage and reduce ripple.

[0050] TVS diode (D4): P6KE6A transient voltage suppressor diode, used to suppress transient overvoltage at the output terminal caused by power grid surges, and protect the subsequent circuits.

[0051] LC filter (U6,C20): An LC filter network consisting of a 100μH inductor and a 0.1μF capacitor further purifies the output and provides a clean +5V power supply to the system.

[0052] 3.6V Regulator (U4, MH7240-3V / 6): Linearly regulates the +5V input to 3.6V. The output is equipped with 100μF and 0.1μF filter capacitors to power the LoRa module and ensure its stable and reliable operation.

[0053] 3.3V regulator (U5, MH7240-3V3): Linearly regulates the +5V input to 3.3V, and is also equipped with 100μF and 0.1μF filter capacitors to power the microcontroller and other digital chips.

[0054] Designed for substation scenarios, it features high safety by employing a multi-layered protection mechanism comprised of fuses, varistors, resettable fuses, and TVS diodes. Safety capacitors and isolated power modules are also used to ensure the safety of personnel and equipment.

[0055] Excellent EMC performance: The front-end EMI filtering circuit (X capacitor, common-mode inductor, Y capacitor) effectively suppresses power grid interference, ensuring stable operation of the system in complex electromagnetic environments.

[0056] Multi-stage voltage regulation, from the isolated 5V output to the system +5V, and then to 3.6V and 3.3V, adopts a graded power supply method to provide precise power for different loads.

[0057] High power supply safety: A multi-layered protection mechanism is constructed through fuses, varistors, resettable fuses and TVS diodes, while safety capacitors and isolated power modules are used to ensure personal and equipment safety.

[0058] Excellent EMC performance: The front-end EMI filtering circuit (X capacitor, common mode inductor, Y capacitor) effectively suppresses power grid interference, ensuring stable operation of the system in complex electromagnetic environments.

[0059] Multi-stage voltage regulation: From the isolated 5V output to the system +5V, and then to 3.6V and 3.3V, a graded power supply method is adopted to provide precise power for different loads.

[0060] See Figure 12 It also features an upgrade interface U11 for software upgrades.

[0061] See Figure 7 Grounding stake insertion detection section (KEY1-KEY4): Detection contacts: KEY1-KEY4 are 4 independent mechanical contacts. When the grounding terminal is inserted, the contacts close and pull the input signal low; when not inserted, the contacts open and the signal is high.

[0062] RC filter network: Each input is connected in series with a 1kΩ current-limiting resistor (R18-R21) to prevent short circuits or overcurrent; two 0.1μF capacitors (C1 / C27, C2 / C3, C4 / C28, C29 / C30) are connected in parallel to form a two-stage RC filter, which effectively filters out high-frequency electromagnetic interference and mechanical contact jitter in the substation environment.

[0063] Signal shaping and interference suppression (CD40106S): By utilizing the hysteresis characteristic of the Schmitt trigger, the contact detection signal after RC filtering is shaped into a clean, jitter-free digital level, completely eliminating false triggering caused by interference.

[0064] Power supply processing: A 1μF (C31) and a 10μF (C32) decoupling capacitor, as well as a 600Ω@100MHz ferrite bead (L1), are connected in parallel at the power supply end to further purify the power supply and improve anti-interference capability.

[0065] For substation scenarios, it has the following characteristics: With strong anti-interference capabilities, the combination of RC filtering and Schmitt trigger can effectively cope with switching operation surges, power frequency magnetic fields and high frequency radiation in substations.

[0066] High reliability; eliminates jitter and interference through hardware, avoiding logical flaws that may occur with software anti-shake.

[0067] See Figure 8 The wireless communication section of this embodiment: The wireless communication interface is connected to the LoRa module. A Schmitt trigger is connected in series between the wireless communication interface and the microprocessor. The LoRa module and the Schmitt trigger use independent power inputs. Several grounded high-frequency filter capacitors are connected in parallel between the wireless communication interface and the microprocessor.

[0068] Interface and signal processing: LoRa interface (LoRa1): Provides connection to LoRa modules; Current limiting resistors (R13-R17): 1kΩ resistors are connected in series in the signal line to limit the current and prevent short circuits or overvoltage from damaging the device.

[0069] Schmitt trigger (U7, CD40106S): Shapes the LORARX and LORATX signals, using its hysteresis characteristics to eliminate signal jitter and glitches caused by interference.

[0070] It also provides two auxiliary signals, M0, M1 and AUX, for configuring the LoRa module's operating mode and read status.

[0071] Power supply and filtering design: Dual power input: 3V6: Powers the RF section of the LoRa module, filtered by a ferrite bead L1 (600Ω@100MHz) and filter capacitors C51 (0.1μF) and C52 (10μF).

[0072] 3V3: Powers the Schmitt trigger U7, filtered by the ferrite bead L2 (600Ω@100MHz) and filter capacitors C55 (0.1μF) and C56 (10μF).

[0073] High-frequency filter capacitors (C53, C54): 10pF capacitors are connected in parallel between the signal line and ground to filter out high-frequency interference and improve signal integrity.

[0074] For substation scenarios, it has the following characteristics: Strong anti-interference: The combination of Schmitt trigger, multi-stage filtering and ferrite bead effectively suppresses the impact of switching operation surges, power frequency magnetic fields and high-frequency radiation on communication signals.

[0075] High reliability: Signal shaping is performed in hardware, avoiding logical loopholes that may occur in software processing.

[0076] See Figure 9In this embodiment, wired communication uses a 485 circuit.

[0077] Among them, the interface and protection circuit: Gas discharge tube (D1, GDTSIP3): As the first level of surge protection, it is used to discharge lightning strikes or operational overvoltages from the cable and clamp the surge to a lower level.

[0078] Self-resetting fuses (F3, F4, SMD0603-010-24): provide overcurrent protection, automatically disconnect in case of bus short circuit or overcurrent, and automatically reset after the fault is cleared.

[0079] Common-mode inductor (L61, FACT4532-510-2P-T): Suppresses common-mode interference, improves signal integrity, and prevents interference from coupling on lines A and B.

[0080] TVS diodes (D6, D7, D8, SMAJ6.8CA): As a second-stage surge protection, they clamp the remaining surge voltage to 6.8V, protecting the RS485 chip in the subsequent stage.

[0081] Bus matching and termination: Termination resistor (R61, 120Ω): Connected in parallel between lines A and B to match bus impedance, reduce signal reflection, and improve the stability of long-distance communication.

[0082] Pull-up / pull-down resistors (R64, R65, 4.7kΩ): Pull line A to 3V3 and line B to GND to maintain a stable differential level when the bus is idle, avoiding misjudgment caused by interference.

[0083] Series resistors (R62, R63, 20Ω): Connected in series between lines A and B, used for current limiting and suppressing high-frequency oscillations, protecting the driving capability of the RS485 chip.

[0084] RS485 transceiver (U60, SP3485EN-L / TR).

[0085] Power supply filtering: The VCC pin is purified by a ferrite bead (L60) and filter capacitors (C68, 10μF; C69, 47μF) to improve anti-interference capability.

[0086] For substation scenarios, it features multi-level surge protection: a combination of gas discharge tube and TVS tube, effectively dealing with lightning strikes and switching operation surges in substations.

[0087] Strong anti-interference: The design of common-mode inductor + termination matching + pull-up / pull-down resistors significantly improves the bus's anti-interference capability and communication stability.

[0088] High reliability: The self-resetting fuse and TVS diode provide comprehensive overcurrent and overvoltage protection, ensuring long-term stable operation of the equipment in harsh environments.

[0089] See Figure 10 In this embodiment, the closed-loop magnetic field detection system based on the HMC1001-RC magnetoresistive sensor is designed for application scenarios with strong electromagnetic interference and wide dynamic range in substations. It integrates four core functions: sensor driving, setting and resetting calibration, differential signal conditioning, and anti-interference protection. The output standard analog quantity can be directly connected to the ADC port of the MCU.

[0090] Magnetoresistive sensing core (U74: HMC1001-RC).

[0091] Device characteristics: Single-axis magnetoresistive sensor, suitable for detecting transient magnetic fields generated by power frequency (50Hz) and switching operations, with set / reset (S / R) calibration function, which can eliminate hysteresis and temperature drift.

[0092] Key circuit design: Differential output matching: R75 and R76 (4.99kΩ precision resistors) provide impedance matching for the sensor's OUT+ and OUT- differential signals to ensure signal transmission integrity.

[0093] Single-ended conversion network: R73, R78, and R71 form a differential-to-single-ended circuit, which converts the millivolt-level differential signal from the sensor into a single-ended voltage suitable for operational amplifier acquisition, adapting to the single-ended input characteristics of the LM321.

[0094] The core purpose of the set / reset (S / R) calibration drive circuit is to periodically apply pulse current to calibrate the HMC1001-RC and eliminate hysteresis errors in magnetic field detection, which is crucial for long-term stable monitoring of substations.

[0095] Circuit principle: Drive switches: Q1A (IRF7105N) and Q2 (IRF7105P) form a complementary MOS transistor drive, which is controlled by the pulse signal output from the MCU-P pin to turn on / off.

[0096] Energy storage and current limiting: R72 (200Ω) limits current, C73 (22μF) stores energy and provides instantaneous high current pulses to the S / R pin.

[0097] Impedance matching: R70 (4.5Ω) matches the impedance of the sensor's S / R pin to avoid calibration failure caused by pulse reflection.

[0098] Gate protection: R713 and R714 (100Ω) are gate current limiting resistors for MOSFETs to prevent overcurrent damage to MCU pins.

[0099] Signal amplification and filtering conditioning circuit: Core component: U76 (LM321MF) low-noise single op-amp, designed for weak signal amplification.

[0100] Circuit configuration and function: Non-inverting amplifier: R761, R764 (10kΩ), and R769 (10kΩ) form an amplifier circuit. The voltage amplification factor Av = 1 + R769 / R764 = 2 times. The resistance value of R769 can be flexibly adjusted according to the magnetic field strength of the substation.

[0101] Active filter: C761 (10nF) and R719 form a low-pass filter with a cutoff frequency of about 1.6kHz, which filters out high-frequency electromagnetic interference in the substation (such as MHz-level spikes generated by switching operations).

[0102] Power supply anti-interference: L761 (600Ω@100MHz ferrite bead), C768, and C762 (100nF+100μF) form a π-type filter to provide a clean 3.3V power supply for the op-amp; D2 (LL4148) is the output clamp to prevent overvoltage from damaging the MCU's ADC pins.

[0103] Interface protection circuit: Core component: U78 (SMF05C) integrated TVS array.

[0104] Protection range: ESD and surge protection is provided for the S / R+, S / R-, OUT+, and OUT- pins of the sensor. The clamping voltage is 5V, which can resist electrostatic discharge and switching surges in substations and prevent damage to sensitive magnetoresistive sensors and conditioning circuits.

[0105] For substation scenarios, it features multi-stage filtering: ferrite beads + capacitors + active filters to effectively cope with lightning strikes, switching operation surges, power frequency magnetic fields, high-frequency radiation, etc. in substations.

[0106] See Figure 11 The status indicator drive circuit designed for strong electromagnetic environments in substations uses transistor amplification and integrates ESD protection to ensure reliable indication of equipment status under complex electromagnetic interference.

[0107] Core Drivers and Protection: Transistor driver (Q3, 2N3904): An NPN transistor used to amplify the control signal output from the MCU and drive an external LED indicator. The base is controlled by the MCU pin (LED1), the collector is connected to the LED through a current-limiting resistor R34, and the emitter is grounded.

[0108] ESD protection (D84, SMBJ3.3A): A TVS diode is connected in parallel between the LED1 pin and ground to clamp electrostatic discharge or surge voltage to 3.3V, protecting the MCU pin from damage.

[0109] Current-limiting resistor (R88, 1kΩ): Connected in series between 3V3 and LED1, it limits the base current and prevents the transistor from being damaged by overcurrent.

[0110] Filtering and decoupling: A 10pF capacitor C88 and a resistor R85 are connected in parallel between the base of the transistor and ground to form a low-pass filter, which filters out high-frequency interference and prevents the transistor from being falsely triggered.

[0111] For substation scenarios, it features strong anti-interference capabilities: the combination of TVS diode and RC filter effectively suppresses electrostatic discharge, switching surges and high-frequency radiation within the substation.

[0112] High reliability: The transistor driving method avoids the overcurrent risk caused by MCU pins directly driving LEDs.

[0113] How to use: When powered on, the corresponding status indicator 32 lights up. Press button 11 on the outer casing 1, and the telescopic iron core 21 will engage and retract from the locking hole 541. Open the waterproof cover 7 to expose the guide post hole of the connector 4. Insert the connecting rod 51 with the grounding rod into the guide post hole 13. Rotate the first fixed handle 56 to the limit stop 12 to press the bottom of the fixed nut 52. Press button 11 and the telescopic iron core 21 will fall into the locking hole 541. Then the wireless communication component will send information to the relevant equipment, and the corresponding status indicator 32 will light up to indicate that the action signal has been received.

[0114] A robust, system-wide design was implemented to address the extremely harsh electromagnetic environment of substations (high voltage, strong magnetic fields, and large surges). Mechanically, it overcomes the limitations of single-specification designs by employing universal connectors for universal compatibility of grounding rods. Architecturally, it successfully introduced wireless communication into the high-voltage safety domain, resolving interference issues and constructing a complete hardware protection chain from power input to signal termination (particularly Schmitt trigger shaping, active S / R calibration, and multi-stage surge discharge), ensuring stable operation of the equipment without system crashes, malfunctions, or damage.

[0115] This case significantly improves the safety, convenience, and reliability of grounding electromagnetic locks in smart grid operation and maintenance.

[0116] This invention is not limited to the above embodiments. Based on the technical solutions disclosed in this invention, those skilled in the art can make some substitutions and modifications to some of the technical features without creative effort, and all such substitutions and modifications are within the protection scope of this invention.

Claims

1. A grounding electromagnetic lock, comprising a housing, an electromagnetic actuation component, and a control circuit board, wherein the electromagnetic actuation component and the control circuit board are both disposed within the housing, and the electromagnetic actuation component is electrically connected to the control circuit board, characterized in that, It also includes a connector and a grounding rod fixing mechanism; the connector is electrically connected to the control circuit board; The grounding rod fixing mechanism includes a connecting rod body, a fixing nut, a first gear, and a second gear. The fixing nut is located on the connecting rod body. A universal connector is detachably provided at the bottom of the connecting rod body for connecting the grounding rod. The first gear and the second gear are rotatably located inside the housing and mesh with each other. A first fixing handle is located below the first gear, and a second fixing handle is located below the second gear. A first elastic component is sleeved on the first fixing handle between the first gear and the housing. A first stop is provided on the first fixing handle. The first stop is used to press tightly against the outer wall of the housing when pulled by the first elastic component. A limiting stop is also provided on the housing. A second elastic component is fitted onto the second fixed handle between the second gear and the housing. The second fixed handle is provided with a second stop, which is used to press tightly against the outer wall of the housing when pulled by the second elastic component. With the connecting rod inserted into the connector, the first and second fixing handles are used to fit tightly against the bottom surface of the fixing nut after rotation.

2. The grounding electromagnetic lock according to claim 1, characterized in that, The control circuit board includes a microprocessor, a power supply circuit, an insertion detection circuit, a wireless communication interface, and an electromagnetic detection interface. The microprocessor is electrically connected to the power supply circuit, the insertion detection circuit, the wireless communication interface, and the electromagnetic detection interface, respectively. The microprocessor is used to execute instructions and process data; the power supply circuit is used to connect to a power source and supply power to the components; the insertion detection circuit is used to detect whether the connecting rod is inserted; the wireless communication interface is used to connect to a wireless communication component; the electromagnetic detection interface is used to connect to an electromagnetic detection component. The connector is located inside the housing, and the housing has a corresponding inlet. The connector has several contacts inside, and all contacts are electrically connected to the insertion detection circuit. The inlet is used to connect the rod body to the connector. The control circuit board is also equipped with a switch for the electromagnetic actuator, and the housing is equipped with a button corresponding to the switch.

3. A grounding electromagnetic lock according to claim 2, characterized in that, The electromagnetic detection component includes a magnetoresistive sensor, a calibration drive circuit, a signal amplification and filtering conditioning circuit, and an interface protection circuit, wherein the magnetoresistive sensor is connected in series with the calibration drive circuit, the signal amplification and filtering conditioning circuit, and the interface protection circuit. The calibration drive circuit is used to calibrate the signal, the signal amplification and filtering conditioning circuit is used to amplify and purify the signal, and the interface protection circuit is used to prevent power surges.

4. A grounding electromagnetic lock according to claim 2, characterized in that, The wireless communication interface is connected to the LoRa module, and a Schmitt trigger is connected in series between the wireless communication interface and the microprocessor. The LoRa module and the Schmitt trigger have independent power inputs. Several grounded high-frequency filter capacitors are connected in parallel between the wireless communication interface and the microprocessor.

5. A grounding electromagnetic lock according to claim 1, characterized in that, The control circuit board is also provided with several indicator units, and the housing is provided with several clearance holes corresponding to the indicator units.

6. A grounding electromagnetic lock according to claim 1, characterized in that, The control circuit board is equipped with a wired communication circuit interface and an early warning unit.

7. A grounding electromagnetic lock according to claim 1, characterized in that, The electromagnetic actuator is also provided with a manual unlocking mechanism, the unlocking port of which is located outside the housing.

8. A grounding electromagnetic lock according to claim 2, characterized in that, The power supply circuit is equipped with an EMI filter circuit consisting of an X capacitor, a common-mode inductor, and several Y capacitors. The EMI filter circuit is connected in series between the microcontroller and the power supply port and is used to suppress electromagnetic interference.

9. A grounding electromagnetic lock according to claim 2, characterized in that, It also includes a grounding stake, one end of which is connected to the plug connector, and the other end of which is used for grounding.

10. A grounding electromagnetic lock according to claim 1, characterized in that, The telescopic iron core of the electromagnetic actuation component is located above the second gear, and the second gear is provided with a locking hole that matches the telescopic iron core; the locking hole is used to prevent the second gear from rotating. The telescopic iron core is fitted with a third elastic component, one end of which abuts against the telescopic iron core and the other end of which abuts against the mounting plate of the electromagnetic actuation component.

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