AC / DC continuous voltage trigger protection device

Abstract

An AC / DC continuous voltage trigger protection device comprises a voltage division circuit which is connected with a breaker to be detected, and further comprises a detection module which is connected with the voltage division circuit and comprises a DC output module, a signal transmission module and a judgment execution module, the direct current output module is used for uniformly converting voltage on the voltage division circuit into direct current signals, the signal transmission module continuously transmits signals to the judgment execution module when the direct current signals exist on the direct current output module, and the judgment execution module cuts off a power supply on the circuit breaker to be tested when the existence duration of the signals exceeds a set threshold value. The beneficial effects of the utility model are that the detection module monitors the voltage change in the test process of the to-be-tested circuit breaker in real time, especially the holding time of the arcing voltage when the moving and static contacts are broken, and can automatically judge the safety of the test process.

Description

Technical Field

[0001] The utility model relates to a protection device, in particular to an AC / DC continuous voltage trigger protection device. Background Art

[0002] AC / DC continuous voltage trigger protection devices are widely used in photovoltaic power generation systems, electric vehicle charging infrastructure, and industrial power equipment to ensure the safe operation of the system in an AC / DC hybrid voltage environment. In these scenarios, the device continuously monitors the input voltage. When the detected voltage exceeds the preset safety threshold (such as overvoltage or undervoltage), it immediately triggers a protection mechanism, such as driving a circuit breaker to break the circuit, to prevent equipment overload, short circuit, or insulation failure. During the testing of photovoltaic inverters or the verification of circuit breakers, this device is often used to simulate grid fluctuations or fault conditions to help evaluate the tolerance of the equipment. The typical usage process includes connecting the test equipment, setting the voltage range, starting the monitoring module, and automatically performing protection actions in case of abnormalities. The whole process emphasizes fast response and reliability to ensure the stable operation of high-value test platforms such as laboratory simulation systems.

[0003] However, the existing technology has significant defects, especially when conducting critical current breaking tests on photovoltaic circuit breakers under conditions of large voltage spans and multiple rated voltage ranges. Due to the insufficient response accuracy of the device under a wide voltage spectrum (such as from low-voltage DC to high-voltage AC) and limited dynamic adjustment ability, triggering delays or misoperations are likely to occur during the test. This results in the inability to break the circuit in a timely manner at the critical current point, leading to continuous arcing, overheating and burning of the test equipment, which not only increases the test failure rate and maintenance costs, but also may pose safety hazards. Summary of the Utility Model

[0004] In view of the deficiencies of the existing technology, the utility model provides an AC / DC continuous voltage trigger protection device that can continuously monitor the voltage change during the circuit breaker test and timely break the circuit.

[0005] To achieve the above object, the technical solution of the utility model is as follows: An AC / DC continuous voltage trigger protection device includes a voltage dividing circuit connected to the circuit breaker to be tested. It also includes a detection module connected to the voltage dividing circuit. The detection module includes a DC output module, a signal transmission module, and a judgment and execution module. The DC output module is used to uniformly convert the voltage on the voltage dividing circuit into a DC signal. The signal transmission module continuously transmits signals to the judgment and execution module when there is a DC signal on the DC output module. The judgment and execution module cuts off the power supply on the circuit breaker to be tested when the duration of the signal presence exceeds the set threshold.

[0006] The beneficial effects of the present utility model are as follows: By means of the detection module, the voltage change during the test of the circuit breaker to be tested is monitored in real time, especially the holding time of the arcing voltage when the moving and static contacts are separated, and the safety of the test process can be automatically judged. When the duration of the arcing voltage exceeds the preset safety threshold, the device immediately cuts off the power supply on the circuit breaker to be tested, thereby protecting the test equipment from arc damage and avoiding equipment failures caused by overvoltage or continuous arcing. As a preferred method, the DC output module can adopt a bridge rectifier structure to uniformly convert the AC-DC mixed signal output by the voltage division circuit into a stable DC voltage. This structure realizes polarity self-adaptation through a diode network, ensuring that the output is a unidirectional DC regardless of the polarity of the input voltage, which is convenient for subsequent signal processing. At the same time, the signal transmission module can be designed as an optoelectronic isolation unit, using a light-emitting element and a light-receiving element to achieve electrical isolation. When the DC signal exists, the light-emitting element activates the light-receiving element to output a continuous signal, effectively preventing high-voltage interference from affecting the judgment accuracy. The judgment execution module integrates a programmable timing function, measures the signal duration through an internal timer, and triggers the cut-off mechanism once it exceeds the limit, improving the response speed and reliability of the system and ensuring stable operation in a complex test environment. This solution not only simplifies the voltage monitoring process but also enhances the versatility and safety of the device, and is applicable to various circuit breaker test scenarios.

[0007] Furthermore, the DC output module includes a rectifier bridge.

[0008] The rectifier bridge can uniformly rectify the AC-DC input signal into a unidirectional DC signal, which is convenient for providing a stable working power supply for the entire detection module, eliminating the compatibility problem caused by the polarity difference of the input voltage, and reducing the signal processing error. As a preferred method, the rectifier bridge can be designed as a full-wave bridge rectifier circuit, which consists of four diodes to form a symmetric structure. When the AC is input, both the positive and negative half-cycles are converted into a forward DC; when the DC is input, the output direction is automatically adjusted according to the polarity. This structure ensures that the current only flows in a predetermined direction through the one-way conduction characteristic of the diode, avoiding reverse voltage impact, and at the same time cooperating with filtering elements (such as capacitors) to smooth the output voltage ripple, improving the stability of the DC signal. This not only reduces the risk of mis-triggering of subsequent modules but also enhances the adaptability of the device in an AC-DC mixed environment, simplifies the circuit design, and prolongs the component life.

[0009] Furthermore, the DC output module also includes two unidirectional conduction circuits connected to the output end of the voltage division circuit, and each unidirectional conduction circuit is provided with several diodes with the same current flow direction.

[0010] This structure realizes three key functions: polarity adaptation to ensure compatibility with positive and negative connections of AC and DC; overvoltage protection, limiting the voltage amplitude through diode clamping; auxiliary rectification, suppressing reverse spikes to improve signal stability. As a preferred method, a unidirectional conduction circuit can use a multi-stage series diode group, with 3-5 diodes in series in each path to form a voltage clamping path. When the input voltage exceeds the rated value, the diode forward conducts to limit the voltage within a safe range to prevent overvoltage from damaging subsequent circuits. At the same time, the diode group works in conjunction with the rectifier bridge to strengthen directional constraints when AC input is applied, block reverse transient voltages, and absorb spike noise through forward conduction characteristics; provide additional rectification layers when DC input is applied to reduce ripple interference. This improves the smoothness of signal transmission, reduces the probability of false triggering of sensitive components such as optocouplers, and ensures reliable operation of the device in a voltage fluctuation environment.

[0011] Furthermore, the signal transmission module includes a photoelectric coupler and a filter capacitor located between the photoelectric coupler and the DC output module. The light source of the photoelectric coupler is connected to the DC output module, and the light receiver is connected to the judgment execution module.

[0012] The photocoupler realizes the isolated conversion from voltage to switch signal, provides electrical isolation to avoid high-voltage interference; the filter capacitor suppresses the ripple and noise in the DC signal, ensures the voltage is stable, and reduces false triggering. As a preferred method, the photocoupler can use a photoisolator structure, in which the light source is a light-emitting diode (LED) and the light receiver is a phototransistor. When the DC signal is input, the LED emits light to activate the phototransistor to output the switch signal, realizing complete isolation of the high and low voltage areas. The filter capacitor uses an electrolytic capacitor in parallel at the rectifier output end, with a capacity of 10-100μF. It absorbs high-frequency ripple and instantaneous spikes through the charge and discharge characteristics, so that the voltage of the input photocoupler remains smooth. This solution not only improves the accuracy of signal transmission, but also enhances the anti-interference ability, ensuring that the subsequent modules will only be triggered under a stable DC signal, avoiding false operations caused by voltage fluctuations.

[0013] Furthermore, the judgment execution module includes a test power supply, a relay and a PLC for powering the judgment execution module, the two ends of the relay are respectively connected to the two input ends of the PLC, the relay includes contacts that change the on-off state when power is turned on, and when the time after the contact changes state is set to a threshold, the PLC cuts off the power supply to the circuit breaker to be tested through an actuator.

[0014] This structure allows for precise control of the cutting-off logic. The relay converts the voltage signal into a switch state input to the PLC. The PLC determines the arc-burning duration based on the time threshold and executes the cut-off to ensure a quick response to protect the equipment. As a preferred method, the relay can be designed as an electromagnetic relay, whose contacts are connected to the input port of the PLC. When a DC signal exists, the contacts close or open to transmit the switch signal to the PLC. The PLC internally integrates a timer function and sets a threshold (such as 1 - 10 ms). Once the duration of the change in the contact state exceeds the threshold, the PLC outputs a control signal to the power actuator (such as an AC contactor). This actuator drives the main circuit breaker through a coil to achieve a quick disconnection of high current or high voltage. This improves the intelligent level of the system. Combining with the programmability of the PLC, the threshold parameters can be flexibly adjusted to adapt to different test conditions and ensure that the protection action is timely and reliable. Description of the Drawings

[0015] Figure 1 It is the circuit schematic diagram of the detection module in the embodiment of the present utility model;

[0016] Figure 2 It is the circuit schematic diagram of the voltage-dividing circuit in the embodiment of the present utility model;

[0017] Figure 3 It is the circuit schematic diagram of the connection between the PLC and the relay in the embodiment of the present utility model. Detailed Embodiment

[0018] An AC / DC continuous voltage trigger protection device in an embodiment of the present utility model is as Figures 1-3 shown: The device includes a voltage-dividing circuit 2. The voltage-dividing circuit 2 has an interface 21 for connecting to a circuit breaker under test (not shown in the figure), and is used to divide the voltage under test during the test of the circuit breaker under test (not shown in the figure), so as to reduce the high voltage to a level suitable for detection. The voltage-dividing circuit 2 uses a common resistor voltage-dividing network or other existing technologies to achieve the voltage-dividing function. The detection module 3 is connected to the output end of the voltage-dividing circuit 2. The detection module 3 includes a DC output module 31, a signal transmission module 32, and a judgment and execution module 33. The DC output module 31 is used to uniformly convert the voltage on the voltage-dividing circuit 2 into a DC signal, and it includes a rectifier bridge 311, and the rectifier bridge 311 can rectify an AC or DC input signal into a unidirectional DC signal. The DC output module 31 also includes two unidirectional conduction circuits 312. Each unidirectional conduction circuit 312 is connected to the output end of the voltage-dividing circuit 2. Each path includes a plurality of diodes 3121 with the same current flow direction. These diodes 3121 ensure the unidirectional flow of current and provide functions such as polarity self-adaptation, overvoltage clamping, and auxiliary rectification.

[0019] The signal transmission module 32 is connected to the output end of the DC output module 31, and includes an optocoupler 321 and a filter capacitor 322. The filter capacitor 322 is located between the optocoupler 321 and the DC output module 31, and is used to filter the rectified DC voltage to suppress ripples and spike voltages. The light-emitting source of the optocoupler 321 is connected to the DC output module 31, and the light-receiving device is connected to the judgment and execution module 33 to realize the isolation conversion of voltage signals into switch signals. The judgment and execution module 33 includes a test power supply 331, a relay 332, and a PLC 333. The test power supply 331 provides working power for the judgment and execution module 33. Both ends of the relay 332 are respectively connected to two input ends of the PLC 333. The relay 332 has a contact 3321, and when energized, the on-off state of the contact 3321 is changed. The PLC 333 is configured to monitor the change duration of the state of the contact 3321.

[0020] During the breaker test, the voltage divider circuit 2 continuously outputs the voltage change between the moving and static contacts (not shown in the figure) of the breaker under test, especially the arcing voltage. When the moving and static contacts (not shown in the figure) are separated to generate a voltage, the voltage divider circuit 2 outputs a voltage-divided signal to the DC output module 31. The DC output module 31 converts the input voltage into a stable DC signal through a rectifier bridge 311 and a unidirectional conduction circuit 312. At the same time, the diode 3121 realizes polarity self-adaptation (compatible with AC / DC forward and reverse connection), overvoltage protection (clamping excessive voltage), and auxiliary rectification (suppressing reverse spikes and ripples). This DC signal is input to the signal transmission module 32. The filter capacitor 322 smooths the voltage fluctuation. The optocoupler 321 is activated when the DC signal exists, and the lighting of the light-emitting source causes the light-receiving device to conduct, generating a continuous switch signal and transmitting it to the judgment and execution module 33. In the judgment and execution module 33, after the relay 332 receives the switch signal, it changes the contact state, and the PLC 333 detects this state and times; if the signal existence duration exceeds a preset safety threshold (such as corresponding to the arcing time limit), the PLC 333 immediately triggers an instruction to cut off the test main power supply on the breaker under test (not shown in the figure) through the connected actuator (not shown in the figure), thereby protecting the test equipment from arc damage.

[0021] The above embodiments are only one of the preferred specific embodiments of the present invention, and the general changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are included in the protection scope of the present invention.

Claims

1. An AC / DC continuous voltage trigger protection device, including a voltage dividing circuit, the voltage dividing circuit is connected to the circuit breaker to be measured, and is characterized in that: It further includes a detection module connected to the voltage dividing circuit. The detection module includes a DC output module, a signal transmission module, and a judgment and execution module. The DC output module is used to uniformly convert the voltage on the voltage dividing circuit into a DC signal. The signal transmission module continuously transmits a signal to the judgment and execution module when there is a DC signal on the DC output module. The judgment and execution module cuts off the power supply of the circuit breaker under test when the duration of the signal presence exceeds a set threshold.

2. The AC-DC continuous voltage trigger protection device according to claim 1, wherein: The DC output module includes a rectifier bridge.

3. The AC / DC continuous voltage trigger protection device according to claim 2, wherein: The DC output module further includes two unidirectional conduction circuits connected to the output end of the voltage dividing circuit. Each unidirectional conduction circuit is provided with a plurality of diodes with the same current flow direction.

4. The AC / DC continuous voltage trigger protection device according to claim 1, characterized in that: The signal transmission module includes an optocoupler and a filter capacitor located between the optocoupler and the DC output module. The light emitting source of the optocoupler is connected to the DC output module, and its light receiving device is connected to the judgment and execution module.

5. The AC / DC continuous voltage trigger protection device according to claim 4, characterized in that: The judgment and execution module includes a test power supply for powering the judgment and execution module, a relay, and a PLC. The two ends of the relay are respectively connected to two input ends of the PLC. The relay includes a contact whose on-off state changes when it is energized. When the contact changes its state and lasts for a set threshold time, the PLC cuts off the power supply of the circuit breaker under test through an actuator.

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