Non-contact high-voltage equipment live detection and safety locking device

Abstract

The application discloses a kind of non-contact high-voltage equipment live detection and safety locking device, including electric field induction sensor module, for sensing the electric field signal of three-phase high-voltage live body, and input protection circuit, for filtering high-frequency noise and limiting input signal amplitude;Signal amplification circuit, filter and direct current separation circuit, for filtering high-frequency interference noise, removing direct current component;Detection circuit, comparison judgment and threshold adjustment circuit, live display and output locking circuit, control logic module, interlocking signal output module;Control logic module controls live display and output locking circuit to display the live state of three-phase high-voltage live body, and controls the knife gate of three-phase high-voltage live body through interlocking signal output module;The application can realize reliable detection and fast locking of high-voltage equipment live state, with strong anti-interference, good environmental adaptability, high safety characteristics, especially suitable for offshore wind power and other harsh working conditions under high-voltage equipment maintenance safety protection.

Description

Technical Field

[0001] This invention relates to the field of electrical safety detection and protection technology, specifically to a non-contact live-line detection and safety interlocking device for high-voltage equipment. Background Technology

[0002] Before installation, inspection, and maintenance of high-voltage equipment, it is essential to reliably verify its energization status. This is a mandatory requirement to ensure the safety of personnel. Non-contact high-voltage live-line display and interlocking devices determine the energization status of high-voltage equipment by sensing the electric field around it and outputting an interlocking signal to prevent misoperation. They have become important safety protection equipment in power systems.

[0003] Existing non-contact high-voltage live-line detection technologies are primarily based on the principle of capacitive induction. Typical domestic products include the BDXN3E inductive high-voltage live-line indicator, which uses an inductive sensor and controller to achieve live-line indication and interlocking; the GSN2 series uses a capacitive sensor with high sensitivity; and the DXNQ series utilizes the principle of capacitive voltage division for signal transmission. Foreign products such as the Kries CAPDISS2+ series, ABB VisiVolt™ series, and Siemens SITRANS series offer advantages in signal processing, self-testing, and communication interfaces. These devices generally meet the requirements for use in typical indoor environments.

[0004] However, when faced with special application scenarios such as offshore wind power and offshore platforms, existing technical solutions reveal significant shortcomings in environmental adaptability and reliability. First, they lack tolerance to extreme environments: the offshore environment is characterized by high humidity, high salt spray, strong wind vibration, and biofouling corrosion. Most existing devices are designed indoors, and their sealing performance, the corrosion resistance of the outer casing materials, and the three-proof treatment of the internal circuit boards generally do not meet the requirements for long-term stable operation at sea. For example, salt spray can easily lead to connector corrosion and circuit moisture absorption, resulting in performance degradation or failure. Second, they suffer from poor reliability under complex electromagnetic interference: offshore wind power platforms experience broadband electromagnetic interference generated by wind turbine inverters and high-power transformers, as well as mechanical vibration noise caused by wave impact. The signal processing circuits of existing devices often use fixed-threshold comparators or simple filter networks, which have weak resistance to pulse interference and transient fluctuations. Under strong interference, they are prone to false triggering (false blocking) or missed detection, posing a safety hazard during maintenance. Secondly, the level of functional integration and intelligence is low: most existing devices only realize local energization indication and hard contact interlocking output, lacking self-diagnosis of sensor health status, adaptive compensation of environmental parameters (such as salt spray concentration, temperature and humidity), and remote status monitoring and data management functions, which cannot meet the needs of intelligent operation and maintenance of modern power systems.

[0005] In summary, there is an urgent need for a non-contact high-voltage live detection and safety interlocking device that can adapt to harsh environments with high humidity, high salt spray, and strong electromagnetic interference, has high reliability, strong anti-interference capabilities, and a certain level of intelligence, in order to ensure the safety of high-voltage equipment maintenance operations in emerging fields such as offshore wind power.

[0006] With the global energy structure transformation and the rapid development of the offshore wind power industry, the scale of offshore high-voltage power systems is constantly expanding, and equipment installation, inspection, and maintenance operations are becoming increasingly frequent. Before inspecting high-voltage equipment, it is essential to accurately determine whether it is energized to ensure the safety of personnel. Traditional voltage detection methods mostly use contact voltage detectors, which suffer from problems such as complex operation, low efficiency, and the risk of electric shock. Non-contact high-voltage live-line display devices, based on the principle of electric field induction, determine the energized state by detecting the electric field strength around the high-voltage equipment. They offer advantages of safety and convenience and are gradually becoming the mainstream technology. Summary of the Invention

[0007] The purpose of this invention is to provide a non-contact high-voltage equipment live-line detection and safety interlocking device, which is suitable for harsh environments such as high salt spray, strong electromagnetic interference, and extreme temperature and humidity at sea, ensuring detection accuracy and operational stability.

[0008] To achieve the above functions, this invention designs a non-contact high-voltage equipment live detection and safety interlocking device, including an electric field induction sensor module, an input protection circuit, a signal amplification circuit, a filtering and DC blocking circuit, a detection circuit, a comparison judgment and threshold adjustment circuit, a live display and output interlocking circuit, a control logic module, and an interlocking signal output module.

[0009] The electric field induction sensor modules correspond to the three-phase high-voltage live conductors, specifically to phases A, B, and C. They are used to sense the electric field signals of the live conductors and output three-phase alternating voltage signals. Each phase's alternating voltage signal is input to the control logic module's input terminal and its corresponding input protection circuit. The input protection circuit filters out high-frequency noise and limits the input signal amplitude. The output terminals of each corresponding input protection circuit are electrically connected to the input terminals of their respective signal amplification circuits. The output terminals of each corresponding signal amplification circuit are electrically connected to the input terminals of their respective filtering and DC blocking circuits. The filtering and DC blocking circuits further filter out high-frequency noise. High-frequency interference noise is removed, and the DC component in the signal is eliminated. The output terminals of the corresponding filtering and DC blocking circuits are electrically connected to the input terminals of the corresponding detection circuits. The output terminals of the corresponding detection circuits are electrically connected to the output terminals of the corresponding comparison judgment and threshold adjustment circuits. The output terminals of the corresponding comparison judgment and threshold adjustment circuits are electrically connected to the input terminals of the control logic module. The output terminals of the control logic module are electrically connected to the live display and output interlocking circuit. The live display and output interlocking circuits are used to display the live status of the three-phase high-voltage live conductors. The output terminals of the control logic module are connected to the interlocking signal output module to control the disconnectors of the three-phase high-voltage live conductors.

[0010] Beneficial effects: Compared with the prior art, the advantages of the present invention include:

[0011] This invention utilizes the principle of electric field induction combined with a mixed-signal circuit design to achieve high-precision monitoring and forced interlocking of high-voltage energized states at sea, and possesses strong resistance to salt spray corrosion, moisture, and electromagnetic interference. The non-contact safety interlocking device described in this invention can be adapted to the extreme operating environment of three-phase high-voltage circuits in offshore wind power, effectively solving the problems of insufficient reliability, large size, and susceptibility to interference in detection accuracy of traditional devices under harsh marine conditions. At the same time, through adaptive delay adjustment and high-density integrated design, it improves operational safety and portability, and reduces maintenance costs. Attached Figure Description

[0012] Figure 1 This is an application diagram of a non-contact high-voltage equipment live-line detection and safety interlocking device according to an embodiment of the present invention;

[0013] Figure 2 This is a circuit diagram of an electric field sensing sensor module provided according to an embodiment of the present invention;

[0014] Figure 3 This is a circuit diagram of an input protection circuit provided according to an embodiment of the present invention;

[0015] Figure 4 This is a circuit diagram of a signal amplification circuit provided according to an embodiment of the present invention;

[0016] Figure 5 This is a circuit diagram of a filtering and DC blocking circuit provided according to an embodiment of the present invention;

[0017] Figure 6 This is a circuit diagram of a detection circuit provided according to an embodiment of the present invention;

[0018] Figure 7 This is a circuit diagram of the comparison judgment and threshold adjustment circuit provided in an embodiment of the present invention;

[0019] Figure 8 This is a circuit diagram of a live display and output latching circuit provided according to an embodiment of the present invention;

[0020] Figure 9 This is a circuit diagram of an interlocking signal output module provided according to an embodiment of the present invention;

[0021] Figure 10 This is a circuit diagram of the control logic module and self-test module provided according to an embodiment of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0023] This invention provides a non-contact high-voltage equipment live-line detection and safety interlocking device, referring to... Figure 1 It includes an electric field induction sensor module, an input protection circuit, a signal amplification circuit, a filtering and DC blocking circuit, a detection circuit, a comparison and threshold adjustment circuit, a live display and output interlocking circuit, a control logic module, and an interlocking signal output module;

[0024] The electric field induction sensor modules correspond to the three-phase high-voltage live conductors, specifically to phases A, B, and C. They are used to sense the electric field signals of the live conductors and output three-phase alternating voltage signals. Each phase's alternating voltage signal is input to the control logic module's input terminal and its corresponding input protection circuit. The input protection circuit filters out high-frequency noise and limits the input signal amplitude. The output terminals of each corresponding input protection circuit are electrically connected to the input terminals of their respective signal amplification circuits. The output terminals of each corresponding signal amplification circuit are electrically connected to the input terminals of their respective filtering and DC blocking circuits. The filtering and DC blocking circuits further filter out high-frequency noise. High-frequency interference noise is removed, and the DC component in the signal is eliminated. The output terminals of the corresponding filtering and DC blocking circuits are electrically connected to the input terminals of the corresponding detection circuits. The output terminals of the corresponding detection circuits are electrically connected to the output terminals of the corresponding comparison judgment and threshold adjustment circuits. The output terminals of the corresponding comparison judgment and threshold adjustment circuits are electrically connected to the input terminals of the control logic module. The output terminals of the control logic module are electrically connected to the live display and output interlocking circuit. The live display and output interlocking circuits are used to display the live status of the three-phase high-voltage live conductors. The output terminals of the control logic module are connected to the interlocking signal output module to control the disconnectors of the three-phase high-voltage live conductors.

[0025] Reference Figure 2 The electric field sensing sensor module includes three identical electric field sensing sensors, each corresponding to a one-to-one configuration of a three-phase high-voltage live conductor. Through spatial electric field coupling between the sensor electrodes and the high-voltage live conductor, it senses alternating voltage signals and outputs weak voltage signals. It maintains a preset safe distance from the high-voltage live conductor and adopts a non-contact electric field coupling design to avoid insulation risks caused by direct contact with the high-voltage live conductor, making it suitable for offshore outdoor installation scenarios.

[0026] Each electric field sensing sensor's equivalent circuit includes a sensing capacitor and a detection circuit equivalent resistance. Through electric field coupling, it senses the alternating voltage signal from the high-voltage charged body, outputting three-phase alternating voltage signals Ua, Ub, and Uc, corresponding to phases A, B, and C of the three-phase high-voltage charged body, respectively. Based on the principle of circuit impedance matching, the induced voltage and the high-voltage circuit voltage have a fixed proportional relationship, ensuring the linearity and accuracy of the signal sensing. Simultaneously, the sensor electrodes employ a corrosion-resistant and insulated design, adapting to the high-salt-spray corrosive environment of the sea.

[0027] In this embodiment, the capacitive electric field sensing sensor is model FSC01. The sensor electrodes are made of stainless steel with a polytetrafluoroethylene (PTFE) anti-corrosion coating, making it suitable for high-salt-spray marine environments. The sensor's equivalent capacitance is 10pF~100pF, the equivalent resistance of the detection circuit is 100kΩ, and the response frequency range is 50Hz~1MHz, meeting the 50Hz power frequency signal detection requirements for offshore wind power. Three sensors correspond to the three-phase high-voltage live conductors (A, B, and C), respectively, and are installed on insulating brackets near the disconnect switches on the inlet / outlet side of the high-voltage equipment. The distance between the front of the sensor electrodes and the high-voltage live conductor is controlled at 8cm (a preset safe distance of 5-10cm) to ensure stable electric field coupling. The insulating brackets are made of epoxy resin with a withstand voltage rating ≥35kV to prevent creepage.

[0028] The sensor's signal output is led out through a high-temperature and corrosion-resistant fluororubber cable, with a cable length not exceeding 1.5m to reduce signal attenuation; both ends of the cable are fixed with waterproof connectors (model: M12-2P) to prevent seawater from seeping in.

[0029] The input protection circuit includes a filtering unit and a limiting unit. Designed to address the high-frequency transient voltages, surges, and peak overvoltages that are prone to occur in offshore wind power systems, it employs a dual protection logic of "filtering + limiting." The filtering unit is an RC filter structure that filters out high-frequency noise in the sensor's induced signal by appropriately matching resistor and capacitor parameters. The limiting unit uses a reverse-parallel silicon diode structure, utilizing the diode's forward voltage characteristics to clamp the output signal amplitude within a safe range, preventing overvoltage surges from damaging subsequent circuit components and ensuring the circuit's shock resistance under complex voltage environments.

[0030] Reference Figure 3 The filtering unit includes a resistor R1 and a capacitor C1 connected in parallel, and the limiting unit includes diodes D1 and D2 connected in reverse parallel.

[0031] One end of resistor R1 is connected to the output terminal of one of the electric field sensing sensors in the electric field sensing sensor module, and is also connected to one end of capacitor C1, the anode of diode D2, and the cathode of diode D1. The other end of capacitor C1 is connected to the other end of resistor R1 and serves as the output terminal of the input protection circuit. The anode of diode D1 and the cathode of diode D2 are both connected to the output terminal of the input protection circuit. Furthermore, the anode of diode D1 and the cathode of diode D2 are grounded. The cathode of diode D1 is connected to a +0.7V reference voltage, and the anode of diode D2 is connected to a -0.7V reference voltage, forming a reverse parallel limiting structure. The reference voltage is provided by a DC ±12V power supply through a voltage divider resistor (10kΩ).

[0032] In this embodiment, resistor R1 is a metal film resistor (model: RJ12-1 / 4W-100kΩ±1%), which has high precision, low temperature drift, and strong corrosion resistance; the resistance of resistor R1 is 100Ω; capacitor C1 is an NP0 ceramic capacitor (model: CC0603N103J500NT), with a temperature range of -55℃ to 125℃, suitable for marine temperature difference environments; the capacitance of capacitor C1 is 0.01nF; diodes D1 and D2 are silicon switching diodes (model: 1N4148), with a forward voltage of 0.7V, a reverse withstand voltage of 100V, fast response speed, and the ability to quickly clamp overvoltage.

[0033] The signal amplification circuit adopts an inverting proportional amplification architecture, with a high-stability operational amplifier as the core. By precisely matching the ratio of the feedback resistor to the input resistor, a fixed amplification factor is set to achieve linear amplification of weak voltage signals and meet the amplitude requirements of subsequent signal processing. A phase compensation element is added to the circuit to compensate for the phase shift of the amplification circuit, suppress self-excited oscillation under high-frequency signals, and ensure amplification stability in a strong electromagnetic interference environment at sea.

[0034] Reference Figure 4 The signal amplification circuit includes a first operational amplifier U1, resistors R2, R3, and R4, and capacitors C2 and C3; capacitors C2 and C3 are phase compensation capacitors used to compensate for the phase shift of the signal amplification circuit.

[0035] In this configuration, the first operational amplifier U1 is an inverting proportional operational amplifier. One end of resistor R3 is connected to the output of the input protection circuit, and the other end of resistor R3 is connected to the inverting input of the first operational amplifier U1, one end of capacitor C2, and one end of resistor R2. The other ends of capacitor C2 and resistor R2 are connected to the output of the first operational amplifier U1, which serves as the output of the signal amplification circuit. The non-inverting input of the first operational amplifier U1 is connected to one end of resistor R4 and one end of capacitor C3. The other ends of resistor R4 and capacitor C3 are grounded. The positive and negative power supply terminals of the first operational amplifier U1 are respectively input with +12V and -12V voltages. A 100Ω current-limiting resistor and a 0.1μF decoupling capacitor are connected in series on the power supply pins to reduce power supply noise.

[0036] In this embodiment, the first operational amplifier U1 uses an industrial-grade general-purpose operational amplifier LM741CN, with an operating voltage of ±5V~±18V, low input bias current, and temperature drift ≤6μV / ℃, making it suitable for harsh marine environments. Resistors R4 and R2 are 10.0kΩ, and resistor R3 is 100Ω, all of which are metal film resistors (RJ12-1 / 4W) with an accuracy of ±1%, ensuring accurate amplification. The circuit amplification factor is the ratio of R2 to R3, i.e., 100 times. Capacitors C2 (99.8nF) and C3 (97.8nF) are X7R ceramic capacitors (model: GRM188R61A104KA38D), which have high capacitance stability and can effectively suppress self-oscillation.

[0037] Reference Figure 5 The filtering and DC blocking circuit includes a second operational amplifier U2, resistors R5, R6, R7, R8, and R9, and capacitors C4, C5, and C6; the positive and negative power supply terminals of the second operational amplifier U2 are respectively input with +12V and -12V voltages.

[0038] In this circuit, one end of resistor R5 is connected to the output of the signal amplifier circuit, and the other end of resistor R5 is connected to one end of capacitors C4 and C5. The other end of capacitor C5 is connected to one end of resistors R6 and R7. The other ends of capacitor C4 and resistor R6 are grounded. The other end of resistor R7 is connected to the non-inverting input of the second operational amplifier U2. The non-inverting input of the second operational amplifier U2 is connected to one end of resistor R8, and the other end of resistor R8 is grounded. The output of the second operational amplifier U2 is connected to one end of resistor R9, and the other end of resistor R9 is connected to one end of capacitor C6. The other end of capacitor C6 serves as the output of the filtering and DC blocking circuit.

[0039] In this embodiment, the second operational amplifier U2 is a 741C model, which shares a power supply with the signal amplification circuit to simplify the circuit structure; the resistance of resistor R5 is 20kΩ, the resistance of resistor R6 is 100kΩ, and metal film resistors (RJ12-1 / 4W±1%) are selected; the capacitance of capacitor C4 is 97.0nF, the capacitance of capacitor C5 is 0.01nF, and NPO ceramic capacitors are selected to ensure stable filtering parameters; the resistance of resistor R7 is 2 kΩ, and the resistance of resistor R8 is 5.1 kΩ.

[0040] Capacitors C4 and C5, resistors R5 and R6, and the second operational amplifier U2 form a second-order active bandpass filter circuit. Designed for the characteristics of offshore wind power power frequency signals, it precisely filters out high-frequency interference noise other than power frequency signals by optimizing resistor and capacitor parameters and setting a specific cutoff frequency, while retaining effective signal components.

[0041] The second-order active bandpass filter circuit has a cutoff frequency of 3.6kHz, ensuring that the 50Hz power frequency signal passes through without attenuation and filtering out high-frequency interference. It is suitable for the anti-interference requirements of complex electromagnetic environments at sea. Its transfer function is:

[0042]

[0043] In the formula, Let be the transfer function of a second-order active bandpass filter circuit. For complex variables;

[0044] Resistor R9 and capacitor C6 form a DC blocking circuit. The connection point between capacitor C6 and R9 is grounded through a 100kΩ resistor, forming a DC discharge loop to prevent the capacitor from accumulating charge and affecting the DC blocking effect. Resistor R9 has a resistance of 30kΩ and is a metal film resistor (RJ12-1 / 2W-30kΩ±1%), with sufficient power margin and good temperature resistance. Capacitor C6 has a capacitance of 1.007μF and is a tantalum capacitor (model: TAJB106K035RNJ), with a withstand voltage of 35V, low leakage current, and excellent DC blocking effect. The DC blocking circuit adopts a resistor-capacitor series structure, utilizing the characteristics of capacitors "passing AC and blocking DC" and resistors "passing DC and blocking AC" to block the transmission of DC components in the signal, avoid detection reference deviation caused by DC offset, and output a pure and effective AC signal, providing a reliable signal source for subsequent live state judgment. The entire circuit adopts a modular integrated design, and the selection of components for each module follows the principle of marine environment adaptability: priority is given to electronic components that are moisture-resistant, corrosion-resistant, and have a wide operating temperature range. The circuit as a whole has a sealed protection design and can be integrated into a sealed shell. Through waterproof, moisture-proof, and corrosion-resistant structural design, it is suitable for the harsh marine environment of high humidity, high salt spray, and extreme temperature difference, ensuring long-term stable operation.

[0045] The detection circuit is a key component of signal processing, used to convert the amplified and filtered AC signal into a stable DC signal, providing input for subsequent comparison and judgment. Ordinary detector diode circuits suffer from drawbacks such as low precision, susceptibility to distortion, and significant temperature sensitivity. However, the precision detection circuit constructed using operational amplifiers in this invention effectively overcomes these problems, exhibiting excellent temperature stability and signal reproduction capabilities.

[0046] Reference Figure 6 The detection circuit includes a third operational amplifier U3, resistors R10, R11, R12, R13, and R14, capacitors C7, C8, C9, C10, C11, C12, C13, C14, and C15, and diodes D3 and D4.

[0047] In this circuit, the non-inverting input of the third operational amplifier U3 is connected to one end of resistor R11, and the other end of R11 is connected to one end of capacitor C7, one end of resistor R10, and the cathode of diode D3. The other end of capacitor C7, the other end of resistor R10, and the anode of diode D4 are grounded. The cathode of diode D4 is connected to the anode of diode D3 and to the output of the filter and DC blocking circuit. The inverting input of the third operational amplifier U3 is connected to one end of resistors R13 and R14, and the other end of resistor R14 is grounded. The other end of resistor R13 is connected to the output of the third operational amplifier U3. The output terminal and one end of resistor R12 are connected, and the other end of resistor R12 serves as the output terminal of the detector circuit; the positive power supply terminal of the third operational amplifier U3 is +12V and connected to one end of capacitors C12, C13, C14, and C15, and the other end of capacitors C12, C13, C14, and C15 is grounded; the negative power supply terminal of the third operational amplifier U3 is -12V and connected to one end of capacitors C8, C9, C10, and C11, and the other end of capacitors C8, C9, C10, and C11 is grounded.

[0048] In this embodiment, the third operational amplifier U3 is an LM324AJ, serving as the core amplification unit. Utilizing its high input impedance and low output impedance characteristics, and in conjunction with the unidirectional conductivity of the diode, it achieves signal detection. Resistors R10 (200kΩ), R11 (10kΩ), R12 (10kΩ), R13 (100kΩ), and R14 (12kΩ) are used to construct the amplification circuit and bias circuit. The capacitance of capacitor C7 is 1.053nF. The capacitances of capacitors C8, C9, C10, and C11 are 96.5nF, 96.9nF, 97.6nF, and 96.5nF, respectively. The capacitances of capacitors C12, C13, C14, and C15 are 96.5nF, 96.1nF, 93.4nF, and 98.6nF, respectively. These capacitors serve as power supply filter capacitors to stabilize the power supply voltage and reduce the impact of power supply noise on detection accuracy.

[0049] The operating logic of the detection circuit is as follows:

[0050] 1. When the input voltage Ui < 0, diode D4 is turned on and D3 is turned off. At this time, the signal flows directly to the ground through D4. No current flows through resistors R10, R11 and capacitor C7, and the operational amplifier output voltage Uo is zero.

[0051] 2. When the input voltage Ui > 0, diode D4 is cut off and D3 is turned on. Resistor R10 and capacitor C7 form a filter circuit to filter out residual high-frequency noise in the signal, making the signal more stable.

[0052] 3. Utilizing the virtual short characteristic of the operational amplifier, the voltage at point A is input to the operational amplifier through the non-inverting input. By configuring the resistors R13 and R14 in a ratio, the signal is amplified by (1+R13 / R14), and finally a stable DC voltage Uo is output. This voltage signal is proportional to the amplitude of the input AC signal.

[0053] Through the above design, the detection circuit can accurately extract the effective components in the AC signal and convert them into a stable DC signal. It also has good temperature stability and anti-interference ability, providing a reliable input signal for subsequent comparison and threshold adjustment circuits.

[0054] The comparison and threshold adjustment circuit is used to analyze and judge the detected DC signal, and outputs a corresponding control signal according to the preset threshold voltage to drive the live display device and the lockout relay to operate. It is the core circuit for realizing the live detection and lockout functions of the device.

[0055] Reference Figure 7 The comparison and threshold adjustment circuit includes a fourth operational amplifier U4, resistors R15, R16, R17, R18, R19, and R20, capacitors C16, C17, C18, C19, C20, C21, C22, and C23, and Zener diodes D5 and D6.

[0056] In this configuration, the non-inverting input of the fourth operational amplifier U4 is connected to one end of resistors R15 and R18. The other end of resistor R15 is connected to one end of resistors R17 and R16. The other end of resistor R17 is grounded. The other end of resistor R16 is connected to the positive power supply terminal of the fourth operational amplifier U4, as well as one end of capacitors C16, C17, C18, and C19. The positive power supply terminal of the fourth operational amplifier U4 receives a +50V voltage. The other ends of capacitors C16, C17, C18, and C19 are grounded. The other end of capacitor C18 is connected to resistors R19 and R20. One end of resistor R19 is connected to the output of the fourth operational amplifier U4; the other end of resistor R20 serves as the output of the comparison judgment and threshold adjustment circuit, and is connected to the anode of Zener diode D5. The cathode of Zener diode D5 is connected to the cathode of Zener diode D6, and the anode of Zener diode D6 is grounded. The negative power supply terminal of the fourth operational amplifier U4 receives a -50V voltage and is connected to one end of capacitors C20, C21, C22, and C23. The other ends of capacitors C20, C21, C22, and C23 are grounded. The negative inverting input terminal of the fourth operational amplifier U4 is left floating.

[0057] In the comparison and threshold adjustment circuit, Zener diodes D5 and D6 are model 1N5233B, used to stabilize the threshold voltage reference and prevent power supply fluctuations from affecting the judgment accuracy. The fourth operational amplifier U4 serves as the core comparison unit; its inverting input receives the detected DC signal, and its non-inverting input obtains the adjustable threshold voltage through a sampling resistor. Resistors R17 have a resistance of 1kΩ, R15 has a resistance of 3kΩ, R16 has a resistance of 5.1kΩ, and R18 has a resistance of 200kΩ. The resistor R19 has a resistance of 2kΩ, the resistor R20 has a resistance of 20kΩ, and the capacitors C16, C17, C18, and C19 have capacitance values ​​of 96.5nF, 96.1nF, 93.4nF, and 98.6nF, respectively; the capacitors C20, C21, C22, and C23 have capacitance values ​​of 96.5nF, 96.9nF, 97.6nF, and 96.5nF, respectively. These multiple filter capacitors are used to filter out high-frequency noise in the signal, ensuring the stability of the comparison results.

[0058] The working principle of the comparison judgment and threshold adjustment circuit is as follows:

[0059] 1. Threshold Voltage Setting: By adjusting the resistance ratio of sampling resistors R16 and R17, the threshold voltage Vref at the non-inverting input of the operational amplifier can be flexibly set. The calculation formula is Vref = R17 × Vcc / (R17 + R16). In this embodiment, when Vcc is 50V, by appropriately selecting the resistance values ​​of R16 and R17, the threshold voltage corresponding to the high output level is set to 8.166V, and the threshold voltage corresponding to the low output level is set to 7.186V.

[0060] 2. Determining the state of being charged:

[0061] When the high-voltage system is energized, the detected DC voltage signal is input to the inverting input of the operational amplifier. If the voltage value is greater than the threshold voltage (8.166V) of the non-inverting input, the operational amplifier outputs a low level. This low-level signal is driven by the BJT tube and sent to the interlocking device to lock the relay and drive the red LED to light up, indicating that the equipment is energized.

[0062] When the high-voltage system is not energized, the DC voltage Ui input at the inverting terminal is 0 and less than the threshold voltage (7.186V) at the non-inverting terminal. The operational amplifier outputs a high level. This high-level signal is driven by the BJT tube, which unlocks the relay and drives the green LED to light up, indicating that the equipment is operable.

[0063] 3. Hysteresis Characteristic Implementation: The circuit achieves hysteresis characteristics through an internal feedback mechanism. When the input voltage at the inverting input is greater than 8.166V, the operational amplifier outputs a low level, and the threshold voltage is updated to 7.186V. As long as the input voltage is greater than or equal to 7.186V, the output remains low. When the input voltage decreases to below 7.186V, the output switches to a high level, and the threshold voltage returns to 8.166V. This characteristic effectively avoids device malfunctions caused by voltage fluctuations near the threshold, improving the reliability of the system.

[0064] Reference Figure 8 The live display and output interlocking circuit includes a reverse buffer U5, which has input pins 1A, 2A, 3A, 4A, 5A, and 6A; and output pins 1Y, 2Y, 3Y, 4Y, 5Y, and 6Y. 1A and 2A correspond to phase A display control, 3A and 4A to phase B display control, and 5A and 6A to phase C display control. Output pins 1Y and 2Y are connected to the anodes of the red and green LEDs in phase A, 3Y and 4Y to the red and green LEDs in phase B, and 5Y and 6Y to the red and green LEDs in phase C. The cathodes of all LEDs are grounded via a 220Ω current-limiting resistor to ensure the diode operating current remains stable at 10-20mA and to prevent overcurrent damage. The circuit includes a positive operating voltage pin (VDD) and a negative operating voltage pin (VSS). The live display and output latching circuit also includes capacitors C24, C25, C26, and C27; resistors R21, R22, R23, R24, R25, and R26; and LEDs D7, D8, D9, D10, D11, and D12. LEDs D7, D9, and D11 are red LEDs, while LEDs D8, D10, and D12 are green LEDs. The LEDs are high-brightness red and green dual-color LEDs with an operating voltage of 2.0-2.2V and a luminous intensity ≥5000mcd, ensuring clear visibility even in strong light conditions at sea. Waterproof packaging is also used to enhance environmental adaptability. LEDs are used to display the status of the three-phase high-voltage lines A, B, and C. A high-level signal drives the corresponding color LED (red or green) to conduct and emit light, ensuring that only one color LED is lit at a time, thus clearly distinguishing between the energized and de-energized states.

[0065] The control logic module's six output terminals are connected to the input pins 1A, 2A, 3A, 4A, 5A, and 6A of the inverting buffer U5, respectively. Input pins 1A, 3A, and 5A are connected to one end of capacitors C25, C26, and C27, respectively, while the other ends of capacitors C25, C26, and C27, as well as the negative voltage pin VSS, are grounded. The positive voltage pin VDD is connected to +12V and is also connected to one end of capacitor C27, with the other end of C27 grounded. Output pin 1Y is connected to input pin 1A and to one end of resistor R21, with the other end of resistor R21 connected to the anode of LED D7. Output pin 2Y is connected to one end of resistor R22, with the other end of resistor R22 connected to the anode of LED D8, and the cathodes of LEDs D7 and D8 are grounded.

[0066] Output pin 3Y is connected to input pin 4A and to one end of resistor R23. The other end of resistor R23 is connected to the anode of LED D9. Output pin 4Y is connected to one end of resistor R24. The other end of resistor R24 ​​is connected to the anode of LED D10. The cathodes of LED D9 and LED D10 are grounded.

[0067] Output pin 5Y is connected to input pin 6A and to one end of resistor R25. The other end of resistor R25 is connected to the anode of LED D11. Output pin 6Y is connected to one end of resistor R26. The other end of resistor R26 is connected to the anode of LED D12. The cathodes of LEDs D11 and D12 are grounded.

[0068] In this embodiment, the inverting buffer U5 is a HEF4049BT, with an operating voltage range of 3-18V and a propagation delay time of less than 100ns, meeting the driving requirements of high-frequency signals and possessing good anti-electromagnetic interference capabilities, adapting to the complex electromagnetic environment at sea. In each display driving channel, the output pin of the previous channel is connected in series with the input pin of the next channel, so that after the input signal is inverted twice, the two sets of output pins output high and low level signals respectively, where the high level signal drives the corresponding color LED to conduct.

[0069] The capacitance values ​​of capacitors C24, C25, and C26 are 0.1μF, the capacitance value of capacitor C27 is 0.1F, the resistance values ​​of resistors R21, R23, and R25 are 5.36kΩ, and the resistance values ​​of resistors R22, R24, and R26 are 5.10kΩ.

[0070] Reference Figure 9The interlocking signal output module is configured with 3 sets of single-phase control nodes (A-phase control node, B-phase control node, and C-phase control node) and 2 sets of three-phase control nodes. Each set of single-phase control nodes is connected to a set of electromagnetic relays. The electromagnetic relays are of model HH52P, with a coil voltage of 12V and a contact capacity of AC220V / 5A and DC24V / 10A. They can be adapted to the control circuit voltage level of offshore wind power high-voltage equipment and have good anti-vibration and anti-salt spray performance. The positive terminal of each electromagnetic relay coil is connected to a +12V power supply via a 1kΩ current-limiting resistor. The negative terminal of each electromagnetic relay coil is connected to the three-way interlocking control output and two-way three-phase joint control output of the control logic module. The normally open and normally closed contacts of each electromagnetic relay are led out as external interfaces. The contacts of the three single-phase control nodes are connected to the control circuit of the corresponding phase grounding switch to monitor the energized status of the three-phase high-voltage line. The contacts of the two three-phase joint control nodes are connected to the control circuit of the bus grounding switch and the bay gate to jointly control the three phases A, B, and C.

[0071] The control logic module includes an integrated circuit chip. Its input terminal receives the live detection signals output by the corresponding comparison judgment and threshold adjustment circuits, and its output terminal drives the light-emitting diodes in the live display and output interlocking circuits and the electromagnetic relays in the interlocking signal output module to turn on and off.

[0072] Reference Figure 10 The control logic module uses an STC89C52 microcontroller, operating at 5V, with 8-bit data processing capability, fast instruction execution speed, and a built-in watchdog timer to effectively prevent program crashes, improve circuit anti-interference capabilities, and adapt to the complex electromagnetic environment at sea. The microcontroller receives a high-voltage energization detection signal (high level indicates energization, low level indicates de-energization) after being sensed, amplified, filtered, detected, compared, and adjusted by the front-end sensor. Based on preset logic, it outputs control commands: when any phase is detected to be energized, the corresponding red LED illuminates, and all relay coils are energized, with contacts switching to a locked state to prohibit operation; when all three phases are de-energized, green LEDs illuminate, relay coils are de-energized, and contacts switch to an unlocked state to allow operation; when the device has no power supply, the relay coils are de-energized, maintaining a forced locked state to prevent accidental operation in the absence of power.

[0073] It also includes a self-test module. This module triggers a self-test command via an external self-test button, outputting simulated live and de-energized signals to the live display and output interlocking circuit. Simultaneously, it sends an action command to the interlock signal output module, checking whether the red and green LEDs are lit correctly and whether the relays accurately respond to interlocking and unlocking actions. This allows for timely detection of device malfunctions and ensures its operational effectiveness. One end of the self-test button is grounded, and the other end is connected to the microcontroller's external interrupt pin. Pressing the button triggers the microcontroller to execute the self-test program.

[0074] In normal operating mode, when the front end detects high voltage energization in phase A, the control logic module receives the high-level detection signal from phase A and outputs a control signal to make pin 1A of the reverse buffer high. After two inversions, pin 1Y becomes low and pin 2Y becomes high, illuminating the red LED in phase A. Simultaneously, the microcontroller energizes the coil of the phase A relay, closing the normally open contacts and opening the normally closed contacts, locking the control circuit of the phase A disconnect switch and preventing operation. If multiple phases are energized simultaneously, the corresponding red LEDs will all light up, and the relevant relays will all activate to achieve locking. When all three phases detect low-level signals, the control logic module outputs a signal to make the input pins of each phase of the reverse buffer low. After inversion, the output pins corresponding to the green LEDs become high, illuminating all three phase green LEDs. The microcontroller then de-energizes all relay coils, opening the normally open contacts and closing the normally closed contacts, unlocking the control circuits of each operating mechanism and allowing normal operation. When the device loses power, both the reverse buffer and the microcontroller stop working, the LEDs turn off, the relay coils are de-energized, keeping normally closed contacts closed and normally open contacts open, and all operating mechanisms are forcibly locked to prevent misoperation. In self-test mode, pressing the self-test button triggers an external interrupt in the microcontroller, entering the self-test program. First, it outputs a simulated energized signal to control the red LEDs of each phase to light up, and simultaneously controls all relays to operate, simulating a locked state. After a 2-second delay, it outputs a simulated de-energized signal to control the green LEDs of each phase to light up, and the relays reset, simulating an unlocked state. If the LEDs light up normally and the relays respond promptly, the device is working normally. If there is an abnormality, the fault can be located by observing the corresponding LED status and relay operation.

[0075] In summary, the non-contact high-voltage equipment live-line detection and safety interlocking device designed in this invention solves the following technical problems in the prior art:

[0076] 1. Inappropriate sensor selection: Traditional contact sensors have limitations in insulation size, are prone to single-phase grounding faults and partial discharge, and are not suitable for marine outdoor environments; ordinary inductive sensors have weak anti-interference capabilities and are easily affected by the complex electromagnetic environment and dense wires at sea, resulting in confused detection signals and insufficient accuracy.

[0077] 2. Insufficient input protection capability: Offshore wind power systems are prone to high-frequency transient voltages, surges, and spike overvoltages. Existing detection circuits lack effective input protection design and are unable to withstand such voltage surges, which can easily damage subsequent circuits.

[0078] 3. Poor signal amplification stability: The sensor output signal is usually a weak voltage signal, which needs to be amplified before subsequent analysis. Existing amplification circuits have problems such as unstable amplification factor and easy self-excited oscillation, which affect the signal transmission accuracy.

[0079] 4. Poor filtering and DC blocking performance. The electromagnetic interference in the marine environment is complex, with a lot of high-frequency noise. Existing filtering circuits have limited effectiveness in filtering out high-frequency interference. At the same time, DC components may be mixed into the signal. The lack of targeted DC blocking design leads to distortion of the detection signal and affects the accuracy of subsequent energized state judgment.

[0080] 5. Technical defects in offshore wind power applications include simple display logic, insufficient interlocking function, weak environmental adaptability, and lack of self-checking mechanism.

[0081] 6. Poor environmental adaptability: Offshore wind power platforms are subject to high humidity, high salinity, and frequent wind and wave impacts. The selection of existing circuit components and structural design have not fully considered such harsh environments, making them prone to corrosion, moisture, and other problems, which leads to decreased circuit reliability and shortened service life.

[0082] The 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 above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A non-contact live-line detection and safety interlocking device for high-voltage equipment, characterized in that, It includes an electric field induction sensor module, an input protection circuit, a signal amplification circuit, a filtering and DC blocking circuit, a detection circuit, a comparison and threshold adjustment circuit, a live display and output interlocking circuit, a control logic module, and an interlocking signal output module; The electric field induction sensor modules correspond to the three-phase high-voltage live conductors, specifically to phases A, B, and C. They are used to sense the electric field signals of the live conductors and output three-phase alternating voltage signals. Each phase's alternating voltage signal is input to the control logic module's input terminal and its corresponding input protection circuit. The input protection circuit filters out high-frequency noise and limits the input signal amplitude. The output terminals of each corresponding input protection circuit are electrically connected to the input terminals of their respective signal amplification circuits. The output terminals of each corresponding signal amplification circuit are electrically connected to the input terminals of their respective filtering and DC blocking circuits. The filtering and DC blocking circuits further filter out high-frequency noise. High-frequency interference noise is removed, and the DC component in the signal is eliminated. The output terminals of the corresponding filtering and DC blocking circuits are electrically connected to the input terminals of the corresponding detection circuits. The output terminals of the corresponding detection circuits are electrically connected to the output terminals of the corresponding comparison judgment and threshold adjustment circuits. The output terminals of the corresponding comparison judgment and threshold adjustment circuits are electrically connected to the input terminals of the control logic module. The output terminals of the control logic module are electrically connected to the live display and output interlocking circuit. The live display and output interlocking circuits are used to display the live status of the three-phase high-voltage live conductors. The output terminals of the control logic module are connected to the interlocking signal output module to control the disconnectors of the three-phase high-voltage live conductors.

2. The non-contact high-voltage equipment live-line detection and safety interlocking device according to claim 1, characterized in that, The electric field sensing sensor module includes three identical electric field sensing sensors, each corresponding to a one-to-one configuration of the three-phase high-voltage live conductors, and maintaining a preset safe distance from the high-voltage live conductors. The equivalent circuit of each electric field sensing sensor includes a sensing capacitor and a detection circuit equivalent resistance. It senses the alternating voltage signal of the high-voltage live conductor through electric field coupling and outputs three-phase alternating voltage signals Ua, Ub, and Uc, respectively, corresponding to phases A, B, and C of the three-phase high-voltage live conductors.

3. The non-contact high-voltage equipment live-line detection and safety interlocking device according to claim 2, characterized in that, The input protection circuit includes a filtering unit and a limiting unit; wherein the filtering unit includes a resistor R1 and a capacitor C1 connected in parallel, and the limiting unit includes diodes D1 and D2 connected in reverse parallel. One end of resistor R1 is connected to the output terminal of one of the electric field sensing sensors in the electric field sensing sensor module, and is also connected to one end of capacitor C1, the anode of diode D2, and the cathode of diode D1. The other end of capacitor C1 is connected to the other end of resistor R1 and serves as the output terminal of the input protection circuit. The anode of diode D1 and the cathode of diode D2 are both connected to the output terminal of the input protection circuit. Furthermore, the anode of diode D1 and the cathode of diode D2 are grounded, the cathode of diode D1 is connected to a +0.7V reference voltage, and the anode of diode D2 is connected to a -0.7V reference voltage.

4. The non-contact high-voltage equipment live-line detection and safety interlocking device according to claim 3, characterized in that, The signal amplification circuit includes a first operational amplifier U1, resistors R2, R3, and R4, and capacitors C2 and C3. In this configuration, the first operational amplifier U1 is an inverting proportional operational amplifier. One end of resistor R3 is connected to the output terminal of the input protection circuit, and the other end of resistor R3 is connected to the inverting input terminal of the first operational amplifier U1, one end of capacitor C2, and one end of resistor R2. The other end of capacitor C2 and the other end of resistor R2 are connected to the output terminal of the first operational amplifier U1, which serves as the output terminal of the signal amplification circuit. The non-inverting input terminal of the first operational amplifier U1 is connected to one end of resistor R4 and one end of capacitor C3. The other end of resistor R4 and the other end of capacitor C3 are grounded. The positive and negative power supply terminals of the first operational amplifier U1 are respectively input with +12V and -12V voltages.

5. A non-contact high-voltage equipment live-line detection and safety interlocking device according to claim 4, characterized in that, The filtering and DC blocking circuit includes a second operational amplifier U2, resistors R5, R6, R7, R8, and R9, and capacitors C4, C5, and C6; the positive and negative power supply terminals of the second operational amplifier U2 are respectively input with +12V and -12V voltages. In this circuit, one end of resistor R5 is connected to the output of the signal amplifier circuit, and the other end of resistor R5 is connected to one end of capacitors C4 and C5. The other end of capacitor C5 is connected to one end of resistors R6 and R7. The other ends of capacitor C4 and resistor R6 are grounded. The other end of resistor R7 is connected to the non-inverting input of the second operational amplifier U2. The non-inverting input of the second operational amplifier U2 is connected to one end of resistor R8, and the other end of resistor R8 is grounded. The output of the second operational amplifier U2 is connected to one end of resistor R9, and the other end of resistor R9 is connected to one end of capacitor C6. The other end of capacitor C6 serves as the output of the filtering and DC blocking circuit.

6. A non-contact high-voltage equipment live-line detection and safety interlocking device according to claim 5, characterized in that, The detection circuit includes a third operational amplifier U3, resistors R10, R11, R12, R13, and R14, capacitors C7, C8, C9, C10, C11, C12, C13, C14, and C15, and diodes D3 and D4. In this circuit, the non-inverting input of the third operational amplifier U3 is connected to one end of resistor R11, and the other end of R11 is connected to one end of capacitor C7, one end of resistor R10, and the cathode of diode D3. The other end of capacitor C7, the other end of resistor R10, and the anode of diode D4 are grounded. The cathode of diode D4 is connected to the anode of diode D3 and to the output of the filter and DC blocking circuit. The inverting input of the third operational amplifier U3 is connected to one end of resistors R13 and R14, and the other end of resistor R14 is grounded. The other end of resistor R13 is connected to the output of the third operational amplifier U3. The output terminal and one end of resistor R12 are connected, and the other end of resistor R12 serves as the output terminal of the detector circuit; the positive power supply terminal of the third operational amplifier U3 is +12V and connected to one end of capacitors C12, C13, C14, and C15, and the other end of capacitors C12, C13, C14, and C15 is grounded; the negative power supply terminal of the third operational amplifier U3 is -12V and connected to one end of capacitors C8, C9, C10, and C11, and the other end of capacitors C8, C9, C10, and C11 is grounded.

7. A non-contact high-voltage equipment live-line detection and safety interlocking device according to claim 6, characterized in that, The comparison and threshold adjustment circuit includes a fourth operational amplifier U4, resistors R15, R16, R17, R18, R19, and R20, capacitors C16, C17, C18, C19, C20, C21, C22, and C23, and Zener diodes D5 and D6. In this configuration, the non-inverting input of the fourth operational amplifier U4 is connected to one end of resistors R15 and R18. The other end of resistor R15 is connected to one end of resistors R17 and R16. The other end of resistor R17 is grounded. The other end of resistor R16 is connected to the positive power supply terminal of the fourth operational amplifier U4, as well as one end of capacitors C16, C17, C18, and C19. The positive power supply terminal of the fourth operational amplifier U4 receives a +50V voltage. The other ends of capacitors C16, C17, C18, and C19 are grounded. The other end of capacitor C18 is connected to resistors R19 and R20. One end of resistor R19 is connected to the output of the fourth operational amplifier U4; the other end of resistor R20 serves as the output of the comparison judgment and threshold adjustment circuit, and is connected to the anode of Zener diode D5. The cathode of Zener diode D5 is connected to the cathode of Zener diode D6, and the anode of Zener diode D6 is grounded. The negative power supply terminal of the fourth operational amplifier U4 receives a -50V voltage and is connected to one end of capacitors C20, C21, C22, and C23. The other ends of capacitors C20, C21, C22, and C23 are grounded. The negative inverting input terminal of the fourth operational amplifier U4 is left floating.

8. A non-contact high-voltage equipment live-line detection and safety interlocking device according to claim 7, characterized in that, The live display and output latching circuit includes an inverting buffer U5, which has input pins 1A, 2A, 3A, 4A, 5A, and 6A; output pins 1Y, 2Y, 3Y, 4Y, 5Y, and 6Y; a positive working voltage pin VDD; and a negative working voltage pin VSS. The live display and output latching circuit also includes capacitors C24, C25, C26, and C27; resistors R21, R22, R23, R24, R25, and R26; and LEDs D7, D8, D9, D10, D11, and D12. LEDs D7, D9, and D11 are red LEDs, and LEDs D8, D10, and D12 are green LEDs. The control logic module's six output terminals are connected to the input pins 1A, 2A, 3A, 4A, 5A, and 6A of the inverting buffer U5, respectively. Input pins 1A, 3A, and 5A are connected to one end of capacitors C25, C26, and C27, respectively, while the other ends of capacitors C25, C26, and C27, as well as the negative voltage pin VSS, are grounded. The positive voltage pin VDD is connected to +12V and is also connected to one end of capacitor C27, with the other end of C27 grounded. Output pin 1Y is connected to input pin 1A and to one end of resistor R21, with the other end of resistor R21 connected to the anode of LED D7. Output pin 2Y is connected to one end of resistor R22, with the other end of resistor R22 connected to the anode of LED D8, and the cathodes of LEDs D7 and D8 are grounded. Output pin 3Y is connected to input pin 4A and to one end of resistor R23. The other end of resistor R23 is connected to the anode of LED D9. Output pin 4Y is connected to one end of resistor R24. The other end of resistor R24 ​​is connected to the anode of LED D10. The cathodes of LED D9 and LED D10 are grounded. Output pin 5Y is connected to input pin 6A and to one end of resistor R25. The other end of resistor R25 is connected to the anode of LED D11. Output pin 6Y is connected to one end of resistor R26. The other end of resistor R26 is connected to the anode of LED D12. The cathodes of LEDs D11 and D12 are grounded.

9. A non-contact high-voltage equipment live-line detection and safety interlocking device according to claim 8, characterized in that, The interlocking signal output module includes three sets of electromagnetic relays, corresponding to phases A, B, and C of the three-phase high-voltage live conductor, respectively. The coil end of each set of electromagnetic relays is connected to the output end of the control logic module, and the contact end is connected in series with the control circuit of the external operating mechanism. The state of the contact switch is controlled by the on / off state of the coil.

10. A non-contact high-voltage equipment live-line detection and safety interlocking device according to claim 9, characterized in that, The control logic module includes an integrated circuit chip. Its input terminal receives the live detection signals output by the corresponding comparison judgment and threshold adjustment circuits, and its output terminal drives the light-emitting diodes in the live display and output interlocking circuits and the electromagnetic relays in the interlocking signal output module to turn on and off.

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