Alternating current test set with protection against reverse line feed

Abstract

The utility model relates to the field of electric power test equipment, concretely is a kind of AC test instrument with anti-line reverse power protection, including voltage regulating unit, step-up transformer, adjustable reactor, measurement and control component, output connecting component and anti-line reverse power protector, voltage regulating unit and step-up transformer are connected, step-up transformer is connected with output connecting component through anti-line reverse power protector, adjustable reactor is parallelly connected with the output end of step-up transformer, anti-line reverse power protector includes switch executor and voltage detection sensor, and the voltage of the output end of step-up transformer is collected in real time by voltage detection sensor, when the voltage of the output end of step-up transformer reaches user set threshold value, measurement and control component judges that reverse power fault occurs in the line to be measured, and measurement and control component controls switch executor to disconnect the connection of step-up transformer and output connecting component, to realize the protection of the circuit element of instrument and operation and maintenance personnel, improve the safety of AC test test.

Description

Technical Field

[0001] This utility model relates to the field of power testing equipment, and in particular to an AC test instrument with protection against reverse power transmission from power lines. Background Technology

[0002] The AC tester is a device used for troubleshooting faults in medium and low voltage power system lines. Its operating voltage is adjustable from 0 to 35kV. It mainly works by inputting high AC voltage into the line and then collecting and diagnosing the AC voltage and current of the line, which can quickly detect faults such as short circuits, grounding, and insulation defects in the line.

[0003] Existing AC power transmitters lack protection against reverse power transmission from the line. Because AC power transmitters detect line faults in a segmented manner, and the AC high voltage input to the line is usually much lower than the line's operating voltage (e.g., for a 10kV line, the output voltage of the AC power transmitter is usually 0-6kV), if the line is energized due to human error or maintenance personnel moving to the wrong section, accidents such as electric shock and equipment burnout can easily occur, causing personal injury and economic property damage.

[0004] In view of this, the present invention proposes an AC test instrument with protection against reverse power transmission to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this utility model is to provide an AC tester with protection against reverse power transmission from the line, so as to solve the technical problem in the background art that the AC tester lacks the protection against reverse power transmission from the line, and when the line is accidentally energized when the AC tester is used to connect the line, it is easy to cause damage to the instrument and personal injury.

[0006] To achieve the above objectives, this utility model provides an AC test instrument with protection against reverse power transmission, comprising:

[0007] The system includes a voltage regulating unit, a step-up transformer, an adjustable reactor, a measurement and control component, an output connection component, and a line reverse power transmission protection device. The line reverse power transmission protection device includes a switch actuator and a voltage detection sensor. The step-up transformer is connected to the output connection component via the switch actuator. The voltage detection sensor is located at one end of the switch actuator. The switch actuator and the voltage detection sensor are respectively connected to the measurement and control component.

[0008] The voltage regulating unit is connected to the input terminal of the step-up transformer, the output of the step-up transformer is connected in parallel with the adjustable reactor, and the voltage regulating unit is connected to the measurement and control component.

[0009] Preferably, in the above technical solution, the switch actuator includes a first conductive rod, a second conductive rod, a flame-retardant corrugated tube, a sleeve, and a lifting mechanism. The first and second conductive rods are both disposed inside the sleeve. One end of the first conductive rod is connected to the output terminal of the step-up transformer. The voltage detection sensor is disposed on the first conductive rod. The flame-retardant corrugated tube is sleeved on the second conductive rod. One end of the second conductive rod extends through the sleeve and is connected to the lifting mechanism and the output connection component, so that the second conductive rod can be driven to move up and down inside the sleeve by the lifting mechanism. The lifting mechanism is connected to the measurement and control component.

[0010] Preferably, in the above technical solution, the lifting mechanism includes a motor and a connecting rod, the connecting rod is connected to the second conductive rod, the connecting rod is provided with a rack, and the output end of the motor is connected to the rack via a gear.

[0011] Preferably, in the above technical solution, the connecting rod is an insulating rod.

[0012] Preferably, in the above technical solution, the output connection component includes a high-voltage connection line and a connector. One end of the high-voltage connection line is connected to the second conductive rod, and the other end is connected to the connector. The connector includes a hook and a high-voltage detector. The hook is connected to the high-voltage connection line.

[0013] Preferably, in the above technical solution, the high-voltage detector includes a probe, a signal processing circuit, and an alarm circuit. The probe is located near the hook and is used to detect the high-voltage AC voltage flowing into the hook. The probe, the signal processing circuit, and the alarm circuit are connected in sequence.

[0014] Preferably, in the above technical solution, the voltage regulating unit includes a voltage regulating circuit and an autotransformer, the voltage regulating circuit is connected to the autotransformer and the measurement and control components respectively, and the autotransformer is connected to the step-up transformer.

[0015] Preferably, in the above technical solution, the measurement and control component includes a microcontroller, a measurement circuit, a button circuit, an automatic discharge circuit, and a display and alarm circuit. The measurement circuit, button circuit, automatic discharge circuit, display and alarm circuit are all connected to the microcontroller, and the measurement circuit and automatic discharge circuit are both connected to the output terminal of the step-up transformer.

[0016] Compared with existing technologies, this utility model has the following beneficial effects.

[0017] 1. This utility model provides a reverse current protection device by installing it at the output end of the step-up transformer and the output connection component. The reverse current protection device includes a switch actuator and a voltage detection sensor. The output connection component is connected to the line under test. The voltage detection sensor collects the voltage value at the output end of the step-up transformer in real time. When the measurement and control component detects that the voltage value collected by the voltage detection sensor exceeds a set threshold, the measurement and control component controls the switch actuator to disconnect the connection between the step-up transformer and the output connection component, thereby cutting off the connection between the line under test and the step-up transformer. This prevents the high voltage of the line under test from being input to the front circuit of the instrument through the step-up transformer, which could cause the instrument to burn out and personnel to be electrocuted, thus improving the safety of the AC test instrument.

[0018] 2. The output connection component of this utility model consists of a high-voltage connection line and a connector. The connector includes a hook and a high-voltage detector. The hook is connected to the high-voltage connection line. In use, the hook is connected to the metal part of the circuit under test. The high-voltage detector is used to detect whether there is high voltage in the circuit under test when the hook approaches or touches the circuit under test. When the high-voltage detector detects that the voltage at the hook exceeds the set threshold, it outputs an audible and visual alarm to remind maintenance personnel to disconnect the circuit under test in time, thereby improving the safety of the test. Attached Figure Description

[0019] Figure 1 This is the overall electrical schematic diagram of this utility model.

[0020] Figure 2 This is a partial sectional view of the switch actuator of this utility model.

[0021] Figure 3 This is a schematic diagram of the output connection component of this utility model.

[0022] In the diagram: 1—Busket, 2—First conductive rod, 3—Flame-retardant corrugated pipe, 4—Second conductive rod, 5—Connecting rod, 6—Motor, 7—Hook, 8—High-voltage detector, 9—Gear, 10—Rack, 100—Voltage regulating unit, 101—Voltage regulating circuit, 102—Measuring circuit, 103—Automatic discharge circuit, 104—Button circuit, 105—Display and alarm circuit, 106—Microcontroller, 107—Switch actuator, 108—Output connection component, 109—Voltage detection sensor, T1—Autotransformer, T2—Step-up transformer, L1—Adjustable reactor; Detailed Implementation

[0023] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. However, it should be understood that the scope of protection of this utility model is not limited to the specific embodiments.

[0024] refer to Figures 1 to 3An AC tester with protection against reverse power transmission from power lines includes a voltage regulating unit 100, a step-up transformer T2, a measurement and control component, a reverse power transmission protection device, an output connection component 108, and an adjustable reactor L1.

[0025] The voltage regulating unit 100 includes a voltage regulating circuit 101 and an autotransformer T1. The voltage regulating circuit 101 is connected to the autotransformer T1, and the autotransformer T1 is connected to the step-up transformer T2. The output terminal of the step-up transformer T2 is connected in parallel with the adjustable reactor L1. The step-up transformer T2 is connected to the output connection component 108 via the switch actuator 107. The voltage regulating circuit 101 is connected to the measurement and control component. By connecting an AC 220V power supply to the input terminal of the voltage regulating circuit 101, the measurement and control component drives the voltage regulating circuit 101 to regulate the input AC voltage and output an AC voltage of 0-220V to the autotransformer T1 for amplification. Finally, the step-up transformer T2 performs a secondary step-up to output a high AC voltage of 0-6kV, with a maximum current output of 70mA. By connecting in parallel with the adjustable reactor L1, the reactance value of the adjustable reactor L1 is set to be close to that of the circuit under test. This compensates for the capacitive current of the cable capacitive test specimen in the circuit under test, reducing the current consumption of the instrument by the capacitive test specimen, reducing the power of the instrument, and making the instrument lighter. In this embodiment, the voltage regulating circuit 100 consists of a single-phase bridge IGBT module and an SPWM wave generator circuit. The measurement and control component drives the single-phase bridge IGBT module to regulate the input AC 220V voltage by driving the SPWM wave generator circuit.

[0026] The reverse current protection device includes a switch actuator 107 and a voltage detection sensor 109. The switch actuator 107 includes a first conductive rod 2, a bushing 1, a flame-retardant corrugated pipe 3, the voltage detection sensor 109, a second conductive rod 4, and a lifting mechanism. Both the first conductive rod 2 and the second conductive rod 4 are housed within the bushing 1, with one end of the second conductive rod 4 extending through the bushing 1 and connecting to the lifting mechanism and the output connection component 108. The lifting mechanism drives the second conductive rod 4 to move up and down within the bushing 1. The flame-retardant corrugated pipe 3 is fitted onto the second conductive rod 4. The first conductive rod 2 is connected to the output terminal of the step-up transformer T2. The voltage detection sensor 109 is mounted on the first conductive rod 2. Both the voltage detection sensor 109 and the lifting mechanism are connected to the measurement and control component. When the first conductive rod 2 and the second conductive rod 4 are in contact, the switch actuator 107 is in the closed position; when the first conductive rod 2 and the second conductive rod 4 are separated, the switch actuator 107 is in the open position. The lifting mechanism includes a connecting rod 5 and a motor 6. The connecting rod 5 is an insulated rod body. The connecting rod 5 is connected to the second conductive rod 4. The connecting rod 5 is provided with a rack 9. The output end of the motor 6 is connected to the rack 9 through a gear 10. After the instrument is connected to the circuit under test, the measurement and control component collects the voltage value at the output terminal of the step-up transformer T2 in real time through the voltage detection sensor 109. When the measurement and control component detects that the voltage at the output terminal of the step-up transformer T2 suddenly rises to the set threshold (when the circuit under test is a 10kV circuit, the threshold is 10kV), it indicates that the circuit has experienced reverse power transmission. The measurement and control component controls the motor 6 of the lifting mechanism to rotate. The motor 6 drives the connecting rod 5 to rotate. The connecting rod 5 drives the second conductive rod 4 to separate from the first conductive rod 2, realizing the tripping of the switch actuator 1071, cutting off the connection between the step-up transformer T2 and the circuit, preventing high voltage from the circuit from being transmitted to the instrument's front-end circuit through the step-up transformer T2 and burning out the instrument. In this embodiment, the bushing 1 is made of insulating material, and its interior is either a vacuum or filled with inert gas, thereby extinguishing the high voltage arc when the second conductive rod 4 separates from the first conductive rod 2. The voltage detection sensor 109 is a VSV701-G150T02 photoelectric voltage sensor.

[0027] The output connection component 108 includes a high-voltage connection cable and a connector. One end of the high-voltage connection cable is connected to the switch actuator 107, and the other end is connected to the connector. The connector includes a hook 7 and a high-voltage detector 8. In use, maintenance personnel connect the connector via a link bar, and then hook the hook 7 of the connector onto the metal part of the circuit under test. The high-voltage detector 8 consists of a probe, a signal processing circuit, and an alarm circuit, which are connected in sequence. The probe collects the magnetic field strength in the circuit under test when the hook 7 is connected to or near the circuit under test. The signal processing circuit amplifies and processes the data. When the magnetic field strength collected by the probe reaches a set threshold, the signal processing circuit controls the alarm circuit to issue an audible and visual alarm to remind maintenance personnel that the circuit is energized or there is reverse power feeding. The hook 7 should be quickly removed from the circuit. In this embodiment, the probe of the high-voltage detector 8 is a Hall sensor.

[0028] The measurement and control components include a measurement circuit 102, an automatic discharge circuit 103, a key circuit 104, a display and alarm circuit 105, and a microcontroller 106. The measurement circuit 102, automatic discharge circuit 103, key circuit 104, and display and alarm circuit 105 are all connected to the microcontroller 106. The measurement circuit 102 is connected to the output terminal of the step-up transformer T2 and is used to detect the current and voltage values ​​at the output terminal of the step-up transformer T2. These values ​​are displayed through the display and alarm circuit 105. The key circuit 104 is used to set the output voltage of the instrument. The microcontroller 106 acquires data from the step-up transformer T2 through the measurement circuit 102. The voltage at the output terminal is compared with the input value of the button circuit 104 for closed-loop feedback adjustment. The automatic discharge circuit 103 is connected to the output of the step-up transformer T2 and is used for automatic discharge after the instrument test ends, abnormal power failure, or fault detection. In specific implementation, the measurement circuit 102 consists of a voltage measurement circuit composed of a voltage divider sampling circuit composed of a sampling resistor and an operational amplifier circuit, and a current measurement circuit composed of a Rogowski coil and an operational amplifier circuit. The automatic discharge circuit 103 consists of a thyristor switch and a discharge resistor connected in series. The microcontroller 106 is an STM32F103C8T6 microcontroller.

[0029] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. An AC test instrument with protection against reverse power transmission from the line, comprising a voltage regulating unit, a step-up transformer, an adjustable reactor, a measurement and control component, and an output connection component, characterized in that, Also includes: A line reverse power transmission protection device includes a switch actuator and a voltage detection sensor. The step-up transformer is connected to the output connection component via the switch actuator. The voltage detection sensor is located at one end of the switch actuator. The switch actuator and the voltage detection sensor are respectively connected to the measurement and control component. The voltage regulating unit is connected to the input terminal of the step-up transformer, the output of the step-up transformer is connected in parallel with the adjustable reactor, and the voltage regulating unit is connected to the measurement and control component. The switch actuator includes a first conductive rod, a second conductive rod, a flame-retardant corrugated tube, a sleeve, and a lifting mechanism. Both the first and second conductive rods are disposed within the sleeve. One end of the first conductive rod is connected to the output terminal of the step-up transformer. The voltage detection sensor is disposed on the first conductive rod. The flame-retardant corrugated tube is sleeved on the second conductive rod. One end of the second conductive rod extends through the sleeve and is connected to the lifting mechanism and the output connection component, so that the second conductive rod can be moved up and down within the sleeve by the lifting mechanism. The lifting mechanism is connected to the measurement and control component.

2. The AC test instrument with anti-reverse power transmission protection according to claim 1, characterized in that, The lifting mechanism includes a motor and a connecting rod. The connecting rod is connected to the second conductive rod. The connecting rod is provided with a rack. The output end of the motor is connected to the rack via a gear.

3. The AC test instrument with anti-reverse power transmission protection according to claim 2, characterized in that, The connecting rod is an insulating rod.

4. The AC test instrument with anti-reverse power transmission protection according to claim 1, characterized in that, The output connection component includes a high-voltage connection line and a connector. One end of the high-voltage connection line is connected to the second conductive rod, and the other end is connected to the connector. The connector includes a hook and a high-voltage detector. The hook is connected to the high-voltage connection line.

5. The AC test instrument with anti-reverse power transmission protection according to claim 4, characterized in that, The high-voltage detector includes a probe, a signal processing circuit, and an alarm circuit. The probe is located near the hook and is used to detect the high-voltage AC voltage flowing into the hook. The probe, the signal processing circuit, and the alarm circuit are connected in sequence.

6. The AC test instrument with anti-reverse power transmission protection according to claim 1, characterized in that, The voltage regulating unit includes a voltage regulating circuit and an autotransformer. The voltage regulating circuit is connected to the autotransformer and the measurement and control components, respectively. The autotransformer is connected to the step-up transformer.

7. The AC test instrument with anti-reverse power transmission protection according to claim 1, characterized in that, The measurement and control component includes a microcontroller, a measurement circuit, a key circuit, an automatic discharge circuit, and a display and alarm circuit. The measurement circuit, key circuit, automatic discharge circuit, and display and alarm circuit are all connected to the microcontroller, and the measurement circuit and automatic discharge circuit are both connected to the output terminal of the step-up transformer.

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