Three-phase inconsistent protection loop sensitivity verification device and method

Abstract

The invention relates to a three-phase inconsistent protection loop sensitivity verification device and method, and the device comprises a main control unit which is connected with an output control unit and a voltage collection circuit, and achieves the closed-loop control of voltage measurement and output control through the output control unit and the voltage collection circuit. The main control unit is respectively connected with the switching value acquisition circuit and the voltage acquisition circuit, and searches the lower limit of the operating voltage of the tested relay according to the test results of the switching value acquisition circuit and the voltage acquisition circuit; the main control unit is respectively connected with the voltage acquisition circuit and the current acquisition circuit, and calculates an action power curve of the tested relay according to measurement results of the voltage acquisition circuit and the current acquisition circuit; the method has the advantages of automatic pressurization, contact state recovery, accurate searching of action voltage, calculation of action power and evaluation of action characteristics.

Description

Technical Field

[0001] This invention belongs to the field of power system relay protection technology, specifically relating to a sensitivity verification device and method for a three-phase inconsistency protection circuit. Background Technology

[0002] High-voltage transmission lines generally use circuit breakers with phase-by-phase operation. To prevent circuit breaker maloperation or failure to operate due to inconsistent three-phase positions, the circuit breaker should be equipped with protection against inconsistency in its three-phase position. Figure 1 The wiring diagram for the three-phase inconsistency relay protection shown involves connecting the normally open and normally closed auxiliary contacts of phases A, B, and C in parallel and then in series. A time relay K16 is then activated. When a phase loss, phase failure, or three-phase voltage fluctuation occurs, the intermediate output relay activates after a delay caused by time relay K16. This relay contacts then connect the three-phase trip coil K61 to disconnect other operating phase circuit breakers. To ensure safe power production, the reliability of the three-phase inconsistency relay needs to be tested regularly to improve equipment stability. Traditional testing methods involve manually applying voltage to the test circuit and calculating the operating time of the tested time relay and intermediate relay to ensure that the operating parameters and conditions meet design requirements. Current testing methods have several problems: manually applying voltage is complex, requiring repeated manual voltage adjustments, resulting in a complicated process and insufficient measurement accuracy; manual timing introduces large errors; and manual testing limits the number of test items, making it difficult to detect some hidden problems. Therefore, it is essential to provide a sensitivity verification device and method for a three-phase inconsistency protection circuit that automatically applies voltage, tracks contact status, accurately locates the operating voltage, calculates the operating power, and evaluates the operating characteristics. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a three-phase inconsistency protection circuit sensitivity verification device and method that automatically pressurizes, recovers contact status, accurately finds the operating voltage, calculates the operating power, and evaluates the operating characteristics.

[0004] The purpose of the present application is achieved in that: in the first aspect, a three-phase inconsistent protection circuit sensitivity checking device, comprising a master control unit, the master control unit is connected with output control unit and voltage acquisition circuit respectively, through output control unit and voltage acquisition circuit to realize voltage measurement, output control closed loop control; the master control unit is connected with switch value acquisition circuit and voltage acquisition circuit respectively, through switch value acquisition circuit and voltage acquisition circuit to find the lower limit of the action voltage of the measured relay; the master control unit is connected with voltage acquisition circuit and current acquisition circuit respectively, through voltage acquisition circuit and current acquisition circuit to measure the action power curve of the measured relay; the master control unit starts timing after applying action voltage, pauses timing when the switch value signal measures the action signal, calculates the action time of the measured relay, compares the action time with the expected time, and calibrates the time relay action parameters.

[0005] The master control unit is connected with the output control unit, the output control unit is connected with the program-controlled power supply, and the master control unit regulates the output range of the program-controlled power supply through the output control unit to provide working power for the tested relay coil.

[0006] The master control unit is connected with the voltage acquisition circuit, the voltage acquisition circuit is connected with the positive and negative poles of the output end of the program-controlled power supply, and the master control unit measures the output voltage of the program-controlled power supply through the voltage acquisition circuit to provide basis for the master control unit to regulate the target voltage of the program-controlled power supply through the output control unit.

[0007] The master control unit is connected with the current acquisition circuit, the current acquisition circuit is connected with the positive pole of the output end of the program-controlled power supply, and the master control unit measures the output current of the program-controlled power supply through the current acquisition circuit, that is, the current size of the tested relay coil, to provide basis for the master control unit to calculate the action power of the tested relay.

[0008] The master control unit is connected with the switch value acquisition circuit, the switch value acquisition circuit is connected with the outgoing node of the tested relay, and the closing state of the node is measured to provide judgment basis for the master control unit to judge the relay action.

[0009] The master control unit is also connected with the display unit, and controls the display unit to output display information.

[0010] The master control unit is also connected with the USB interface, and the test record information of the device can be exported through the USB interface.

[0011] The current acquisition circuit includes a resistor R14 and an operational amplifier U4. The first end of the resistor R14 is connected to the positive output line of the programmable power supply, and the second end is connected to the positive power supply of the relay coil under test. The negative input terminal of the operational amplifier U4 is connected to the first end of the resistor R14 through a resistor R10, and is grounded through a parallel resistor R9 and a capacitor C2. The positive input terminal is connected to the second end of the resistor R14 through a resistor R12, and is grounded through a capacitor C5. The negative power supply terminal of the operational amplifier U4 is grounded, the positive power supply terminal is connected to a 3.3V external voltage VCC, and is grounded through a capacitor C1. The positive input terminal of the operational amplifier U4 is connected to the output terminal of the operational amplifier U4 through a resistor R13. The output terminal of the operational amplifier U4 is connected to the main control unit through a resistor R11, and is grounded through a capacitor C6.

[0012] The voltage acquisition circuit includes: a voltage divider sampling module, a first isolation operational amplifier circuit, and a first differential operational amplifier circuit; the voltage divider sampling module is connected to the positive and negative terminals of the programmable voltage output terminal, the first isolation operational amplifier circuit is connected to the voltage divider sampling module, and the first differential operational amplifier circuit is connected to the first isolation operational amplifier circuit.

[0013] Secondly, a method for verifying the sensitivity of a three-phase inconsistency protection circuit, the method comprising the following steps: Step 1: Initial preparation: Connect the relay to be tested to the designated test point to establish the basic connection for subsequent voltage output, action detection and other operations; Step 2: Voltage Output and Action Detection: First, output voltage, then determine if the relay activates: if the relay does not activate, perform the "increase power supply voltage" operation and try to trigger the relay again, repeating this process until the relay activates; if the relay activates, proceed to the subsequent data acquisition and parameter calibration stage. Step 3: Data Collection and Analysis By collecting voltage and current data: voltage and current information is collected synchronously when the relay operates; Generate relay power curve: Based on the collected voltage and current data, the power change curve of the relay is plotted through power calculation to intuitively present its power characteristics; Step 4: Calculation and calibration of motion parameters Apply relay operating voltage: Determine and apply the voltage value that will cause the relay to operate; Calculate relay operating time: Measure the time interval from the application of the operating voltage to the actual operation of the relay; Compare the actual operating time with the expected operating time of the relay to ensure that the relay meets the usage requirements.

[0014] The beneficial effects of this invention are as follows: This invention is a sensitivity verification device and method for a three-phase inconsistency protection circuit. In use, this invention automatically applies pressure, samples the relay contact status, accurately locates the relay operating voltage, calculates the relay operating power, evaluates the relay operating characteristics, and analyzes whether the relay performance meets the three-phase inconsistency control requirements. After locating the relay operating voltage, this invention applies a working voltage above the operating voltage, tests the time relay operating delay error, automatically analyzes whether the time relay meets the three-phase inconsistency control requirements in terms of delay parameters, and performs calibration. This invention has the advantages of automatic pressure application, sampling of contact status, accurate location of operating voltage, calculation of operating power, and evaluation of operating characteristics. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a traditional three-phase inconsistent relay trip control circuit.

[0016] Figure 2 This is a schematic diagram illustrating the structural composition and testing principle of the present invention.

[0017] Figure 3 This is a schematic diagram of the current acquisition circuit of the present invention.

[0018] Figure 4 This is a schematic diagram of the voltage acquisition circuit of the present invention.

[0019] Figure 5 This is a schematic diagram of the switch quantity acquisition circuit of the present invention.

[0020] Figure 6 This is a flowchart illustrating the operation of the present invention. Detailed Implementation

[0021] The main technical problems solved by this invention are: 1. Solving the problem of complex traditional testing operations: Traditional methods require manual repeated pressurization of the test circuit, which is cumbersome and inefficient; this invention automatically applies pressure and collects data on the relay contact status, accurately finding the relay operating voltage and calculating the relay operating power; 2. Solving the problem of large errors in manual timing: Traditional methods rely on manual observation and recording of operating time, which has a large human error; this invention improves the accuracy of time measurement through an automated timing mechanism; 3. Solving the problems of limitations in manual testing items and difficulty in detecting hidden faults: This invention expands the test scenarios and parameters to achieve more comprehensive and in-depth performance verification of three-phase inconsistent relays, improving the reliability of equipment operation; The main problem solved by this invention is to address the shortcomings of traditional testing methods for three-phase inconsistent relays in high-voltage transmission line circuit breakers, providing a more efficient, accurate, and comprehensive testing solution.

[0022] The present invention will be further described below with reference to the embodiments and / or accompanying drawings. Example 1

[0023] like Figures 1-5 As shown, a sensitivity verification device for a three-phase inconsistency protection circuit includes a main control unit. The main control unit is connected to an output control unit and a voltage acquisition circuit, respectively, to achieve voltage measurement and closed-loop output control. It is also connected to a switch quantity acquisition circuit and a voltage acquisition circuit, respectively, to find the lower limit of the operating voltage of the relay under test using the test results from these circuits. Furthermore, it is connected to a voltage acquisition circuit and a current acquisition circuit, respectively, to calculate the operating power curve of the relay under test using the measurement results from these circuits. The main control unit starts timing after applying the operating voltage and pauses timing when the switch quantity signal detects the operating signal, calculating the operating time of the relay under test. By comparing the operating time with the expected time, the operating parameters of the time relay are calibrated.

[0024] The main control unit is connected to the output control unit, which is connected to the programmable power supply. The main control unit adjusts the output range of the programmable power supply through the output control unit to provide working power to the relay coil under test.

[0025] The main control unit is connected to the voltage acquisition circuit, which is connected to the positive and negative terminals of the output of the programmable power supply. The main control unit measures the output voltage of the programmable power supply through the voltage acquisition circuit, providing a basis for the main control unit to regulate the output target voltage of the programmable power supply through the output control unit.

[0026] The main control unit is connected to the current acquisition circuit, which is connected to the positive terminal of the programmable power supply output. The main control unit measures the output current of the programmable power supply through the current acquisition circuit, which is the current of the relay coil under test. This provides a basis for the main control unit to calculate the operating power of the relay under test.

[0027] The main control unit is connected to the switch quantity acquisition circuit, which is connected to the output terminal of the relay under test. By measuring the closed state of the terminal, the main control unit provides a basis for judging the relay operation.

[0028] The main control unit is also connected to the display unit, controlling the display unit to output display information.

[0029] The main control unit is also connected to a USB interface, through which test record information of the device can be exported.

[0030] The current acquisition circuit includes a resistor R14 and an operational amplifier U4. The first end of the resistor R14 is connected to the positive output line of the programmable power supply, and the second end is connected to the positive power supply of the relay coil under test. The negative input terminal of the operational amplifier U4 is connected to the first end of the resistor R14 through a resistor R10, and is grounded through a parallel resistor R9 and a capacitor C2. The positive input terminal is connected to the second end of the resistor R14 through a resistor R12, and is grounded through a capacitor C5. The negative power supply terminal of the operational amplifier U4 is grounded, the positive power supply terminal is connected to a 3.3V external voltage VCC, and is grounded through a capacitor C1. The positive input terminal of the operational amplifier U4 is connected to the output terminal of the operational amplifier U4 through a resistor R13. The output terminal of the operational amplifier U4 is connected to the main control unit through a resistor R11, and is grounded through a capacitor C6.

[0031] In this embodiment, as Figure 3 As shown, the current passing through resistor R14 generates a voltage drop, which is differentially amplified by operational amplifier U4. The amplified voltage signal is then sent to the MCU to complete the conversion from "current to voltage to digital quantity" for subsequent processing by the MCU in the system.

[0032] Specifically, the current acquisition circuit includes a first resistor R14, a second resistor R10, a third resistor R9, a fourth resistor R12, a fifth resistor R13, and a sixth resistor R11; a first capacitor C2, a second capacitor C1, a third capacitor C5, and a fourth capacitor C6; and a first operational amplifier U4. The first end of the first resistor R14 is connected to the positive output line of the programmable power supply, and the second end of the first resistor R14 is connected to the positive power supply of the relay coil under test.

[0033] The negative input terminal of the first operational amplifier U4 is connected to the first terminal of the first resistor R14 through the second resistor R10. The negative input terminal of the first operational amplifier U4 is grounded through the third resistor R9 and the first capacitor C2 connected in parallel. The positive input terminal of the first operational amplifier U4 is connected to the second terminal of the first resistor R14 through the second resistor R12. The positive input terminal of the first operational amplifier U4 is grounded through the third capacitor C5.

[0034] The negative power supply terminal of the first operational amplifier is grounded, and the positive power supply terminal of the first operational amplifier is connected to an external voltage VCC of 3.3V. The positive power supply terminal of the first differential amplifier is grounded through the second capacitor C1, and the positive input terminal of the first operational amplifier is connected to the output terminal of the first operational amplifier through the fifth resistor R13.

[0035] The output of the first operational amplifier is connected to the main control unit through the sixth resistor R11, and the output of the first differential amplifier is grounded through the fourth capacitor C6.

[0036] In summary, the current acquisition circuit uses a high-precision operational amplifier to sample the positive output bus current of the programmable power supply. The acquired analog signal is converted into a digital signal by a 16-bit A / D converter and then transmitted to the main control unit, ensuring that the current measurement range covers 0-10A and the accuracy reaches ±0.5%. After the positive output bus of the programmable power supply is sampled by voltage division by the first resistor R14, it is processed by the first operational amplifier GS8331. The output analog signal is converted into a digital signal by a 16-bit A / D converter and then transmitted to the main control unit for processing.

[0037] The voltage acquisition circuit includes: a voltage divider sampling module, a first isolation operational amplifier circuit, and a first differential operational amplifier circuit; the voltage divider sampling module is connected to the positive and negative terminals of the programmable voltage output terminal, the first isolation operational amplifier circuit is connected to the voltage divider sampling module, and the first differential operational amplifier circuit is connected to the first isolation operational amplifier circuit.

[0038] In this embodiment, as Figure 4 As shown, the voltage acquisition circuit is designed with 4 resistors, with a total resistance exceeding 10MΩ. After the voltage is divided by a high-impedance current-limiting voltage divider at the front end, an optocoupler is designed to isolate and amplify the high voltage. Then, it is differentially amplified by an operational amplifier and finally acquired by the MCU.

[0039] Specifically, the voltage acquisition circuit includes: a voltage divider sampling module 11, a first isolation operational amplifier circuit 22, and a first differential operational amplifier circuit 33; the voltage divider sampling module 11 is connected to the positive and negative terminals of the programmable voltage output terminal, the first isolation operational amplifier circuit 22 is connected to the voltage divider sampling module 11, and the first differential operational amplifier circuit 33 is connected to the first isolation operational amplifier circuit 22.

[0040] ①Among them, such as Figure 4 As shown, the voltage divider sampling module 11 includes a first resistor R133, a second resistor R136, a third resistor R138, a fourth resistor R140, a first capacitor C137, and a second capacitor C138. The first end of the first resistor R133 is connected to the positive output line of the programmable power supply. The first end of the first capacitor C137 is connected to the second end of the first resistor R133. The first end of the first capacitor C137 is connected to the first end of the second resistor R136. The second end of the first capacitor C137 is connected to the negative output bus of the programmable power supply. The second end of the second resistor R136 is connected to the negative output bus of the programmable power supply through the third resistor R138 and the fourth resistor R140. The second end of the second resistor R136 is connected to the negative output bus of the programmable power supply through the second capacitor C138. The second end of the second resistor R136 is connected to the first end of the fifth resistor R8.

[0041] ② The first isolation operational amplifier circuit 22 includes a first isolation amplifier U1 of model AMC1200. The first isolation operational amplifier circuit 22 also includes a third capacitor C3, a fourth capacitor C4, a fifth capacitor C7, a fifth resistor R8, a first inductor L1, and a second inductor L3. The first power supply port VDD1 of the first isolation amplifier U1 is grounded through the third capacitor C3, and the first power supply port VDD1 of the first isolation amplifier U1 is connected to the external voltage VCC1.

[0042] The first positive signal input port VIN+ of the first isolation amplifier U1 is connected to the second end of the fifth resistor R8. The first positive signal input port VIN+ is grounded through the fifth capacitor C7. The first negative signal input port VIN- of the first isolation amplifier U1 is connected to the negative output bus of the programmable power supply. The first negative signal input port VIN- of the first isolation amplifier U1 is grounded.

[0043] The second power supply port VDD2 of the first isolation amplifier U1 is grounded through the fourth capacitor C4, and the second power supply port VDD2 of the first isolation amplifier U1 is connected to the +5V external voltage VCC through the second inductor L3; the first positive signal output port VOUT+ of the first isolation amplifier U1 is grounded.

[0044] ③ The first differential operational amplifier circuit 33 includes an AD8552 first differential amplifier U3B, a sixth resistor R5, a seventh resistor R4, an eighth resistor R13, a ninth resistor R11, a tenth resistor R3, an eleventh resistor R1, a twelfth resistor R9, a sixth capacitor C15, a ninth capacitor C1, and a tenth capacitor C13; the positive input terminal of the first differential amplifier U3B is connected to the first positive signal output port VOUT+ of the first isolated amplifier through the sixth resistor R5, the positive input terminal of the first differential amplifier U3B is connected to a 2.5V reference power supply through the seventh resistor R4, and the positive input terminal of the first differential amplifier U3B is grounded through the parallel eighth resistor R13 and the sixth capacitor C15.

[0045] The negative input terminal of the first differential amplifier U3B is connected to the first negative signal output port VOUT- of the first isolation amplifier through the ninth resistor R11. The negative input terminal of the first differential amplifier U3B is connected to the output terminal of the first differential amplifier U3B through the tenth resistor R3, the eleventh resistor R1 and the ninth capacitor C1 connected in parallel.

[0046] The output of the first differential amplifier U3B is connected to the main control unit through the twelfth resistor R9, and the output of the first differential amplifier U3B is grounded through the tenth capacitor C13.

[0047] In summary, the voltage acquisition circuit uses a high-precision isolation operational amplifier to isolate and sample the positive and negative bus voltages of the programmable power supply output. The acquired analog signals are converted into digital signals by a 16-bit A / D converter and then transmitted to the main control unit, ensuring that the voltage measurement range covers 0-300V with an accuracy of ±0.2%. The programmable power supply output bus voltage is sampled by voltage divider through resistors R133, R136, R138, and R140. After electrical isolation by the first isolation amplifier AMC1200, it is processed by the first differential operational amplifier. The output analog signal is converted into a digital signal by a 16-bit A / D converter and then transmitted to the main control unit for processing.

[0048] As one possible specific implementation, such as Figure 5 As shown, the switch signal acquisition circuit is designed with a logical hierarchy of “signal acquisition → protection conditioning → level conversion → electrical isolation → MCU acquisition”, which ensures that the switch signal can still be stably recognized by the MCU in complex environments (such as electromagnetic interference and surges).

[0049] Specifically, the switching signal acquisition circuit includes: a first varistor Rv, a second resistor R1, a third resistor R2, a fourth resistor R3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first capacitor C1, a second capacitor C5, a third capacitor C4, a first bidirectional diode TVS1, a second diode D1, a third diode D2, a first transistor Q1, a second field-effect transistor Q2, a third transistor Q3, and a fourth field-effect transistor Q4; wherein the first varistor Rv and the first bidirectional diode TVS1 are connected in parallel and connected to the output node of the relay under test; the first terminal of the first bidirectional diode TVS1 is connected to the anode of the second diode D1; the cathode of the second diode D1 is connected to the base of the first transistor Q1 through the second resistor R1; the cathode of the second diode D1 is connected to the first terminal of the first capacitor C1; the second terminal of the first capacitor C1 is connected to the second terminal of the first bidirectional diode TVS1; and the base of the first transistor Q1 is grounded through the third resistor R2 and connected to the second terminal of the first bidirectional diode TVS1.

[0050] The emitter of the first transistor Q1 is grounded, the collector of the first transistor Q1 is connected to the gate of the second field-effect transistor Q2, the gate of the second field-effect transistor Q2 is connected to the drain through the fourth resistor R3, and is connected to the 3.3V external voltage VCC; the drain of the second field-effect transistor Q2 is grounded through the fifth resistor R5 and the second capacitor C5 connected in parallel.

[0051] In addition, the first terminal of the first bidirectional diode TVS1 is connected to the cathode of the third diode D2. The anode of the third diode D2 is connected to the base of the third transistor Q3 through the sixth resistor R6. The emitter of the third transistor Q3 is grounded, and the collector is connected to the gate of the fourth field-effect transistor Q4. The gate of the fourth field-effect transistor Q24 is connected to the drain through the ninth resistor R9 and connected to the 3.3V external voltage VCC. The gate of the fourth field-effect transistor Q4 is grounded through the eighth resistor R8, and the drain of the fourth field-effect transistor Q4 is grounded through the parallel tenth resistor R10 and the third capacitor C4.

[0052] Meanwhile, the drains of the second field-effect transistor Q2 and the fourth field-effect transistor Q4 are connected to the main control unit.

[0053] This invention relates to a sensitivity verification device and method for a three-phase inconsistency protection circuit. In use, this invention automatically applies pressure, samples the relay contact status, accurately locates the relay operating voltage, calculates the relay operating power, evaluates the relay operating characteristics, and analyzes whether the relay performance meets the three-phase inconsistency control requirements. After locating the relay operating voltage, this invention applies a working voltage above the operating voltage, tests the time relay operating delay error, automatically analyzes whether the time relay meets the three-phase inconsistency control requirements in terms of delay parameters, and performs calibration. This invention has the advantages of automatic pressure application, sampled contact status, accurate location of operating voltage, calculation of operating power, and evaluation of operating characteristics. Example 2

[0054] like Figure 6 As shown, a method for verifying the sensitivity of a three-phase inconsistency protection circuit is as follows: Step 1: Initial preparation: Connect the relay to be tested to the designated test point to establish the basic connection for subsequent voltage output, action detection and other operations.

[0055] Step 2: Voltage Output and Action Detection: First, output voltage, then determine if the relay operates: if the relay does not operate, perform the "increase power supply voltage" operation and try to trigger the relay again, repeating this process until the relay operates; if the relay operates, proceed to the subsequent data acquisition and parameter calibration stage, in which voltage and current data are acquired in real time.

[0056] Step 3: Data Collection and Analysis By collecting voltage and current data: When the relay operates, the voltage and current information collected synchronously is the basis for subsequent power calculation and performance analysis; Generate relay power curve: Based on the collected voltage and current data, the power change curve of the relay is plotted through power calculation (P=UI) to intuitively present its power characteristics.

[0057] Step 4: Calculation and calibration of motion parameters Apply relay operating voltage: Determine and apply the voltage value that will cause the relay to operate; Calculate relay operating time: Measure the time interval from the application of the operating voltage to the actual operation of the relay; Compare the actual operating time with the expected operating time of the relay to ensure that the relay meets the usage requirements.

[0058] This invention relates to a sensitivity verification device and method for a three-phase inconsistency protection circuit. In use, this invention automatically applies pressure, samples the relay contact status, accurately locates the relay operating voltage, calculates the relay operating power, evaluates the relay operating characteristics, and analyzes whether the relay performance meets the three-phase inconsistency control requirements. After locating the relay operating voltage, this invention applies a working voltage above the operating voltage, tests the time relay operating delay error, automatically analyzes whether the time relay meets the three-phase inconsistency control requirements in terms of delay parameters, and performs calibration. This invention has the advantages of automatic pressure application, sampled contact status, accurate location of operating voltage, calculation of operating power, and evaluation of operating characteristics.

Claims

1. A sensitivity verification device for a three-phase inconsistency protection circuit, comprising a main control unit, characterized in that: The main control unit is connected to the output control unit and the voltage acquisition circuit, respectively, and realizes voltage measurement and output control closed-loop control through the output control unit and the voltage acquisition circuit. The main control unit is also connected to the switch quantity acquisition circuit and the voltage acquisition circuit, respectively, and finds the lower limit of the operating voltage of the relay under test through the test results of the switch quantity acquisition circuit and the voltage acquisition circuit. The main control unit is also connected to the voltage acquisition circuit and the current acquisition circuit, respectively, and calculates the operating power curve of the relay under test through the measurement results of the voltage acquisition circuit and the current acquisition circuit. The main control unit starts timing after applying the operating voltage, and stops timing when the switch quantity signal measures the operating signal, calculates the operating time of the relay under test, and calibrates the operating parameters of the time relay by comparing the operating time with the expected time.

2. The three-phase inconsistency protection circuit sensitivity verification device as described in claim 1, characterized in that: The main control unit is connected to the output control unit, which is connected to the programmable power supply. The main control unit adjusts the output range of the programmable power supply through the output control unit to provide working power to the relay coil under test.

3. The three-phase inconsistency protection circuit sensitivity verification device as described in claim 2, characterized in that: The main control unit is connected to the voltage acquisition circuit, which is connected to the positive and negative terminals of the output of the programmable power supply. The main control unit measures the output voltage of the programmable power supply through the voltage acquisition circuit, providing a basis for the main control unit to regulate the output target voltage of the programmable power supply through the output control unit.

4. The three-phase inconsistency protection circuit sensitivity verification device as described in claim 3, characterized in that: The main control unit is connected to the current acquisition circuit, which is connected to the positive terminal of the programmable power supply output. The main control unit measures the output current of the programmable power supply through the current acquisition circuit, which is the current of the relay coil under test. This provides a basis for the main control unit to calculate the operating power of the relay under test.

5. The three-phase inconsistency protection circuit sensitivity verification device as described in claim 4, characterized in that: The main control unit is connected to the switch quantity acquisition circuit, which is connected to the output terminal of the relay under test. By measuring the closed state of the terminal, the main control unit provides a basis for judging the relay operation.

6. The three-phase inconsistency protection circuit sensitivity verification device as described in claim 5, characterized in that: The main control unit is also connected to the display unit, controlling the display unit to output display information.

7. The three-phase inconsistency protection circuit sensitivity verification device as described in claim 6, characterized in that: The main control unit is also connected to a USB interface, through which test record information of the device can be exported.

8. The three-phase inconsistency protection circuit sensitivity verification device as described in claim 4, characterized in that: The current acquisition circuit includes a resistor R14 and an operational amplifier U4. The first end of the resistor R14 is connected to the positive output line of the programmable power supply, and the second end is connected to the positive power supply of the relay coil under test. The negative input terminal of the operational amplifier U4 is connected to the first end of the resistor R14 through a resistor R10, and is grounded through a parallel resistor R9 and a capacitor C2. The positive input terminal is connected to the second end of the resistor R14 through a resistor R12, and is grounded through a capacitor C5. The negative power supply terminal of the operational amplifier U4 is grounded, the positive power supply terminal is connected to a 3.3V external voltage VCC, and is grounded through a capacitor C1. The positive input terminal of the operational amplifier U4 is connected to the output terminal of the operational amplifier U4 through a resistor R13. The output terminal of the operational amplifier U4 is connected to the main control unit through a resistor R11, and is grounded through a capacitor C6.

9. The three-phase inconsistency protection circuit sensitivity verification device as described in claim 3, characterized in that: The voltage acquisition circuit includes: a voltage divider sampling module, a first isolation operational amplifier circuit, and a first differential operational amplifier circuit; the voltage divider sampling module is connected to the positive and negative terminals of the programmable voltage output terminal, the first isolation operational amplifier circuit is connected to the voltage divider sampling module, and the first differential operational amplifier circuit is connected to the first isolation operational amplifier circuit.

10. The method for verifying the sensitivity of a three-phase inconsistency protection circuit as described in claim 1, characterized in that: The verification method includes the following steps: Step 1: Initial preparation: Connect the relay to be tested to the designated test point to establish the basic connection for subsequent voltage output, action detection and other operations; Step 2: Voltage Output and Action Detection: First, output voltage, then determine if the relay activates: if the relay does not activate, perform the "increase power supply voltage" operation and try to trigger the relay again, repeating this process until the relay activates; if the relay activates, proceed to the subsequent data acquisition and parameter calibration stage. Step 3: Data Collection and Analysis By collecting voltage and current data: voltage and current information is collected synchronously when the relay operates; Generate relay power curve: Based on the collected voltage and current data, the power change curve of the relay is plotted through power calculation to intuitively present its power characteristics; Step 4: Calculation and calibration of motion parameters Apply relay operating voltage: Determine and apply the voltage value that will cause the relay to operate; Calculate relay operating time: Measure the time interval from the application of the operating voltage to the actual operation of the relay; Compare the actual operating time with the expected operating time of the relay to ensure that the relay meets the usage requirements.

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