Insulation resistance and capacitance measurement circuit and method based on single pulse double-edge analysis

Abstract

The application discloses an insulation resistance and capacitance measuring circuit and method based on single-pulse double-edge analysis, relates to the related field of electrical insulation online monitoring technology, and the circuit comprises a detected object and an insulation detection circuit. The insulation detection circuit comprises a controlled pulse voltage source, a coupling resistance network, a current sensor, a switch control module, a signal modulation circuit and a processor. The measuring method realized based on the circuit comprises the following steps: a pulse emitter is used to inject a common-mode voltage pulse to a transmission line of a power transmission system; pulse current response is collected in real time, a current waveform diagram is drawn, a three-point sampling method is introduced to record current values for insulation impedance parameter calculation; according to a load condition, a double-edge check method is applied based on pulse current attenuation characteristics, insulation impedance parameters, including resistive components and capacitive components, are independently calculated by analyzing a rising edge and a falling edge of the pulse current. The application realizes non-invasive synchronous monitoring of resistive and capacitive components of line-to-ground impedance, and improves detection precision.

Description

Technical Field

[0001] This application relates to the field of online monitoring technology for electrical insulation, and in particular to a circuit and method for measuring insulation resistance and capacitance based on single-pulse dual-edge analysis. Background Technology

[0002] Insulation resistance and capacitance measurement are important aspects of electrical equipment maintenance and operation management, and are widely used in electric vehicle charging systems, photovoltaic power generation, energy storage equipment, and AC / DC power transmission scenarios. Insulation resistance refers to the ratio between the voltage applied between two electrodes in the insulation structure of a power transmission system and the leakage current flowing through that pair of electrodes. It is an important parameter for measuring the insulation of electrical equipment. Capacitors are components that store electrical energy, and their capacitance determines the energy storage capacity of a circuit.

[0003] By regularly measuring insulation resistance, problems such as aging, moisture absorption, and damage to insulation materials can be detected in advance. Corresponding measures can be taken in a timely manner to achieve equipment failure prediction and health management, thereby avoiding faults such as short circuits and leakage in electrical equipment. By measuring the capacitance parameters of capacitors, the quality of capacitors can be evaluated, and problems such as dielectric aging and internal short circuits can be identified. Timely replacement can ensure the reliability of the circuit.

[0004] Traditional measurement methods employ the unbalanced bridge method, which obtains the voltage and leakage current detection results for each output branch by controlling the switching of the balanced and unbalanced bridges in the detection circuit, and calculates the insulation impedance based on the detection results. This method requires switching to form an asymmetrical grounding impedance, establishing a two-equation solution to solve for the resistive component of the impedance to ground, and cannot measure the capacitive component. Moreover, it is only applicable to DC isolation systems and cannot be extended to AC scenarios. It also requires multiple switching operations and has a slow response speed. Summary of the Invention

[0005] To address the technical problems of the prior art, this application provides an insulation resistance and capacitance measurement circuit and method based on single-pulse dual-edge analysis. By introducing a single pulse and combining the current attenuation characteristics of the pulse rising and falling edges, it achieves non-intrusive synchronous monitoring of the line-to-ground impedance, including resistive and capacitive components, compatible with AC and DC systems, and achieving millisecond-level response.

[0006] This application provides an insulation resistance and capacitance measurement circuit based on single-pulse double-edge analysis, comprising the object under test and an insulation detection circuit. The object under test is the resistive component of the impedance of a power transmission line to ground, specifically the first resistance. Second resistor First capacitor of capacitive component Second capacitor The insulation detection circuit includes: a controlled pulse voltage source, a coupling resistor network, a current sensor, a switch control module, a signal modulation circuit, and a processor. The object being tested and the insulation detection circuit are connected in series. The processor in the insulation detection circuit branches off and is connected in series with the controlled pulse voltage source, the coupling resistor network, the current sensor, the switch control module, and the signal modulation circuit, respectively. The branches are connected in parallel.

[0007] The object being tested also includes the power supply voltage. First switch Second switch and load resistance By controlling the different states of two switches, multi-scenario expansion can be achieved:

[0008] When the first switch Second switch When both are disconnected, the power supply voltage and load resistance With the branch disconnected, the detection circuit is connected to both the resistive and capacitive components of the impedance to ground, used to detect the pure line impedance, and includes a first resistor. Second resistor First capacitor Second capacitor ; When the first switch Close, second switch When disconnected, the power supply voltage Branch circuit connected, load resistance Branch circuit disconnected, detection circuit and power supply voltage The resistive and capacitive components of the impedance to ground are connected to realize the voltage at the power supply terminals. Total insulation resistance Total insulation capacitance The joint testing, including total insulation resistance It is the first resistor Second resistor Parallel value, total insulation capacitance It is the first capacitor Second capacitor Parallel values; When the first switch Disconnect, second switch When closed, the power supply voltage Branch circuit disconnected, load resistance Branch connection, detection circuit and load resistor The resistive and capacitive components of the impedance to ground are connected to realize the load terminal voltage and the total insulation resistance. Total insulation capacitance Joint testing.

[0009] The controlled pulse voltage source is controlled by a processor to inject common-mode voltage into the power transmission line. The amplitude is 10-100V, the pulse width is adjustable, and the amplitude is adjustable. The injection point is located between the positive and negative busbars and the protective ground. between.

[0010] The coupling resistor network includes a first coupling resistor. Second coupling resistor This isolates the object being tested from the insulation detection circuit, limits the current in the detection circuit, and protects the detection circuit from damage. The switch control module includes a first control switch. Second control switch To control the on / off state of the insulation detection circuit; First current sensor Second current sensor Used to detect the current value in the circuit, providing real-time data for subsequent plotting of the current waveform, and to analyze the rising and falling edges of the current; The signal modulation circuit includes three The module performs current / voltage conversion, filtering, and amplification. The module is located between the current sensor and the processor. Located in the first coupling resistor On the processor branch, Located in the second coupling resistor On the processor branch; The processor is used to receive current sensor and The module's measurement data is used to calculate the resistive and capacitive components of the power transmission line's impedance to ground based on the three-point sampling method and the double-edge test method, and a warning signal is sent.

[0011] Based on the above insulation resistance and capacitance measurement circuit, this application provides a method for measuring insulation resistance and capacitance based on single-pulse dual-edge analysis, the method comprising: (1) A common-mode voltage pulse is injected into the transmission line of the power transmission system using a pulse transmitter, and then applied to the positive and negative busbars through a coupling resistor; (2) Real-time acquisition of pulse current response, plotting current waveform, and calculation of time constant using three-point sampling method. Record the current values ​​at three different times to measure the insulation resistance parameter; (3) Based on the load conditions, the dual-edge verification method is applied based on the pulse current attenuation characteristics. The insulation impedance parameters, including resistive and capacitive components, are calculated independently by analyzing the rising and falling edges of the pulse current.

[0012] The present invention discloses the following technical effects: This invention proposes a circuit and method for measuring insulation resistance and capacitance based on single-pulse dual-edge analysis. By constructing an insulation detection circuit and introducing a common-mode voltage pulse, it simultaneously measures the insulation impedance and parasitic capacitance of power transmission lines based on a three-point sampling method and a single-pulse dual-edge verification method. This overcomes the limitation of traditional measurement methods that can only measure resistive impedance, enhances the system safety assessment dimension, and provides data support for power system fault prediction and health management. Furthermore, the common-mode pulse injection mechanism proposed in this invention is compatible with both DC and AC power systems, expanding the application scenarios of the measurement method. The insulation detection circuit adopts a non-intrusive design, achieving millisecond-level response without power interruption. The introduction of a dual-edge redundancy verification method improves measurement accuracy by independently calculating resistance and capacitance parameters through analysis of the rising and falling edges of a single pulse. To reduce the computing power requirements of the microcontroller unit, a three-point sampling method is used instead of exponential fitting, improving measurement efficiency. This invention incorporates a dual-switch mechanism, flexibly controlling the detection range of the circuit through different combinations of switch states, achieving switching detection at the line end, power supply end, and load end. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. Flowcharts are used in this application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed precisely in sequence. Instead, various steps can be processed in reverse order or simultaneously as needed. Furthermore, other operations can be added to these processes, or one or more steps can be removed from these processes.

[0014] Figure 1 A schematic diagram of an insulation resistance and capacitance measurement circuit based on single-pulse dual-edge analysis provided in an embodiment of this application.

[0015] Figure 2 A flowchart of an insulation resistance and capacitance measurement method based on single-pulse dual-edge analysis provided in an embodiment of this application.

[0016] Figure 3 This is a schematic diagram of pulse signal injection for the insulation resistance and capacitance measurement circuit based on single-pulse dual-edge analysis provided in an embodiment of this application.

[0017] Figure 4 The first capacitor of the system provided in the embodiments of this application under light load With the first resistor A schematic diagram of the current loop.

[0018] Figure 5 The pulse voltage provided in the embodiments of this application With the first pulse current A schematic diagram of the rising edge waveform.

[0019] Attached chart label: Red line represents pulse voltage Waveform, green line represents the first pulse current. Waveform.

[0020] Figure 6 The first resistor provided in the embodiments of this application under heavy load Second resistor First capacitor Second capacitor A schematic diagram of a circuit that is forced into parallel connection.

[0021] Figure 7 This is a schematic diagram of the pulse current falling edge model provided in an embodiment of this application.

[0022] Figure 8 The first pulse current provided for the embodiments of this application Current waveform at the falling edge.

[0023] Figure 9 This is a schematic diagram illustrating the effect of differential mode current on pulse current sampling, provided in an embodiment of this application. Detailed Implementation

[0024] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application.

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description of this application will be provided in conjunction with the accompanying drawings. The described embodiments should not be considered as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] In the following description, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or modules not explicitly listed or inherent to such processes, methods, products, or devices. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used herein is for the purpose of describing embodiments of this application only.

[0027] Example 1: This application provides a circuit and method for measuring insulation resistance and capacitance based on single-pulse dual-edge analysis. The detailed structure of the circuit is as follows: Figure 1 As shown, it includes the object being tested and the insulation detection circuit.

[0028] The object being tested is the resistive component of the impedance of the power transmission line to ground, specifically the first resistance. Second resistor First capacitor of capacitive component Second capacitor The insulation detection circuit includes: a controlled pulse voltage source. First coupling resistor Second coupling resistor First current sensor Second current sensor First control switch Second control switch Signal modulation circuit and processor.

[0029] Based on the above insulation resistance and capacitance measurement circuit, this application provides a method for measuring insulation resistance and capacitance based on single-pulse dual-edge analysis, such as... Figure 2 As shown, the method includes: Step S10: A common-mode voltage pulse is injected into the power transmission line using a pulse transmitter, and then applied to the positive and negative busbars via a coupling resistor.

[0030] In this embodiment, the pulse signal injection method is as follows: Figure 3 As shown: Injecting common-mode voltage pulses into the power transmission system Close the first control switch Second control switch First pulse current With the second pulse current Through coupling resistor Acting on the power supply terminal and Then, they pass through the first resistor. With the second resistor Return to pulse Common-mode voltage pulse injection avoids interference with the power supply circuit and ensures power supply voltage. Stability, enabling non-invasive measurement; coupling resistor The injected common-mode voltage pulses are distributed to the positive and negative buses to ensure that the pulse signals act uniformly on the buses.

[0031] Step S20: Real-time acquisition of pulse current response, plotting of current waveform, and calculation of time constant using the three-point sampling method. The current values ​​at three different times are recorded to measure the insulation resistance parameter.

[0032] In this embodiment, a three-point sampling method is used to achieve engineering perfection. In actual engineering, the voltage at the initial moment... The voltage oscillates; measure the first pulse current at the start moment. There are difficulties; at the same time, in engineering applications, microcontroller units are generally used as computing units, making it difficult to fit the time constant.

[0033] Three-point sampling method, i.e., recording , and The first pulse current at time 1 , and ,set up The time constant is obtained by recording the current value. The derivation process is as follows: For any time , All satisfy the following formula:

[0034] make Its physical meaning is the total attenuation amplitude of the first pulse current; ,in Indicates common-mode pulse voltage amplitude, You can wait a sufficiently long time before taking direct measurements, therefore Given the quantities, the above equation can be simplified to:

[0035] right and The times are respectively:

[0036]

[0037] and Decrease amplitude at time and Represented as:

[0038]

[0039] Dividing the two equations above, we get:

[0040] Take the natural logarithm of the above expression:

[0041] Therefore, the time constant Represented as:

[0042] Based on the physical meaning of the above equation, it is only necessary to... and The instantaneous first pulse current was measured at each moment. and The steady-state current of the first pulse current was measured. The time constant can then be calculated. This method is used for subsequent calculations of resistance and capacitance, eliminating the need for complex function fitting and reducing the difficulty of engineering applications. It is also applicable to the calculation of the second pulse current. time constant The calculation.

[0043] Step S30: Based on the load conditions, the dual-edge verification method is applied according to the pulse current attenuation characteristics. The insulation impedance parameters, including resistive and capacitive components, are calculated independently by analyzing the rising and falling edges of the pulse current.

[0044] In this embodiment, the rising edge of the pulse current is analyzed first: When the power transmission system is unloaded or lightly loaded, i.e., when the load resistance is... , Indicates the first resistor With the second resistor Parallel connection, first resistor With the second resistor Through load resistance The parallel circuit impedance is relatively large, with the first pulse current Taking the circuit as an example, such as Figure 4 As shown, the circuit includes a pulse voltage source. The voltage value is Coupling resistor First resistor First capacitor and voltage At this point, the first pulse current can be observed. The waveform was analyzed to obtain the first resistance. With the first capacitor , Waveform and Current waveform as follows Figure 5 As shown: from The moment begins According to time constant It shows an exponential trend from decay to Select , and The first resistance was calculated using the three-point sampling method at the sampling time point. With the first capacitor : Given coupling resistance and voltage ,from Read the current value from the current waveform , and In steady state At the moment, the capacitor is equivalent to an open circuit, and the current no longer changes and remains in the horizontal range. Measurements are taken after a sufficiently long time following the end of the pulse. Calculate the total resistance :

[0045] Therefore, the first resistance can be solved. :

[0046] Based on the read current value , and The first resistance obtained by combining the calculation and known coupling resistance Further calculations yielded the first capacitor. Coupling resistor and the first resistor Parallel pair Discharge, time constant Represented as:

[0047] Substituting the time constant calculated in step S20, we can obtain:

[0048] After sorting, we can obtain:

[0049] Substitute We can obtain:

[0050] Similarly, the three-point sampling method is used to measure the second pulse current. exist , and Current value at time , and By combining the known quantities, the second resistance can be calculated. With the second capacitor :

[0051]

[0052] When the power transmission system is heavily loaded or the internal resistance of the power supply is very small, i.e., the load resistance is low... hour, and pass Forced parallel connection, such as Figure 6 As shown, and , and A parallel connection is automatically established, at which point the total loop current can be observed. The total insulation impedance was obtained through analysis. Total insulation capacitance ,in , .

[0053] When the power transmission system is under heavy load, the total current analysis method is used. After injecting a common-mode pulse, the total loop current is detected. At this point, the coupling resistors are also in parallel, so the coupling resistance is... ,right The three-point sampling method is used to measure the current value. , and Calculate the total insulation resistance directly Total insulation capacitance :

[0054]

[0055] To improve measurement accuracy, after performing pulse current rising edge analysis, falling edge analysis is performed on the pulse current to achieve redundancy verification, divided into light load and heavy load cases: When the power transmission system is unloaded or lightly loaded, i.e., when the load resistance is... The falling edge model of the pulse current is as follows: Figure 7 As shown, the pulse source is in At any moment, the voltage from Reduce to 0V, Equivalent to a short circuit, coupling resistor With the first resistor Parallel connection to the first capacitor Discharge, discharge current curve as shown Figure 8As shown, the first pulse steady-state current before the transition. The first pulse steady-state current after the transition .

[0056] When the pulse voltage from When it jumps to 0V, the first capacitor Through the first resistor and coupling resistor Discharge, first pulse current satisfy:

[0057] Among them, the instantaneous first pulse current of the jump The first resistance is calculated using the same three-point sampling method. and the first capacitor : Select before the falling edge time Measure the first pulse current at all times , Selected and At that moment, and Measure the value of the first pulse current and ; According to known and Solve for the first resistance. :

[0058] Further calculation of time constant :

[0059] Based on time constant Calculate the first capacitor :

[0060] Similarly, the three-point sampling method is used to measure the second pulse current. At the falling edge , and Current value at time , and By combining the known quantities, the second resistance can be calculated. With the second capacitor :

[0061]

[0062] When the power transmission system is heavily loaded or the internal resistance of the power supply is very small, i.e., the load resistance is low... hour, and pass Forced parallel connection is achieved using the total current analysis method. After injecting a common-mode pulse, the total loop current is detected. At this point, the coupling resistors are in a parallel relationship. ,right Using the three-point sampling method, the falling edge time is selected. , and Measure current value , and Calculate the total insulation resistance directly Total insulation capacitance :

[0063]

[0064] Measuring the impedance component during the falling edge of the pulse current avoids the instantaneous oscillation when the power is turned on, which helps improve the signal-to-noise ratio. Cross-validation by combining the results of the rising and falling edges of the pulse current reduces measurement errors.

[0065] In practical circuits, such as Figure 9 As shown, due to the two coupling resistors The access will be Introduce a differential mode current The calculation formula is:

[0066] For a steady-state system, It is also in a steady state; The presence of this will affect the first pulse current. Second pulse current Sampling, direction and Same as, with Conversely, considering the influence of differential-mode current on the three-point sampling method, the calculation formulas for the resistive and capacitive components of the impedance are revised as follows: Rising edge phase:

[0067]

[0068] Falling edge phase:

[0069]

[0070] For total insulation resistance Total insulation capacitance ,because For vector sums, the summation process eliminates... The formula remains unchanged despite the influence of [the formula].

[0071] Example 2: This application provides an insulation resistance and capacitance measurement circuit and method based on single-pulse dual-edge analysis, using an electric vehicle charging station as an application example. Figure 1 The detection circuit shown, combined with the measurement process described in Embodiment 1, measures the total insulation impedance and capacitive reactance within the charging pile: According to the national standard GB / T 18487.1-201, the insulation impedance requirements for charging piles are shown in Table 1.

[0072] Table 1. Insulation impedance requirements for charging piles as specified in National Standard GB / T 18487.1-201

[0073] In this embodiment, the pulse power supply voltage is known. Coupling resistor , respectively in , and Measure the total loop current value at all times The measurement data are shown in Table 2.

[0074] Table 2 Measurement data of charging piles in Example 2

[0075] Calculate the total insulation resistance based on the measurement data. Total insulation capacitance :

[0076]

[0077] The total insulation resistance is obtained by calculation Compared with national standards, it can be concluded that the current power transmission system of the charging pile is in the interval alarm stage, sending a warning signal through the processor in the detection circuit. The following is an error analysis of the measurement data; the error between the actual and measured values ​​is shown in Table 3.

[0078] Table 3 Error Analysis of Charging Pile Measurement Data in Example 2

[0079] Error analysis reveals that at steady state... pulse current With total insulation resistance A linear relationship exists. The measurement error is relatively easy to control within ±2%; calculation hour, With time The relationship is exponential; even a slight time deviation in measurement can lead to a large systematic error. By optimizing the time deviation during measurement, the error can be controlled within ±5%.

[0080] The three-point sampling algorithm and single-pulse dual-edge verification method proposed in this invention can simultaneously measure the insulation impedance and parasitic capacitance of a line, and can achieve ±2% impedance error and ±5% capacitive reactance error, which has strong practical value.

[0081] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application. In some cases, the actions or steps described in this application can be performed in a different order than that shown in the embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

Claims

1. An insulation resistance and capacitance measurement circuit based on single-pulse dual-edge analysis, characterized in that, The circuit includes the object being tested and an insulation detection circuit; the object being tested is the resistive component of the impedance to ground of the power transmission line, specifically the first resistance. Second resistor First capacitor of capacitive component Second capacitor The insulation detection circuit includes: a controlled pulse voltage source, a coupling resistor network, a current sensor, a switch control module, a signal modulation circuit, and a processor. The object being detected and the insulation detection circuit are connected in series. The processor in the insulation detection circuit branches off and is connected in series with the controlled pulse voltage source, the coupling resistor network, the current sensor, the switch control module, and the signal modulation circuit, respectively. The branches are connected in parallel. The controlled pulse voltage source is controlled by a processor to inject common-mode voltage into the power transmission line. The amplitude is 10-100V, the pulse width is adjustable, and the amplitude is adjustable. The injection point is located between the positive and negative busbars and the protective ground. between; The coupling resistor network includes a first coupling resistor. Second coupling resistor This isolates the object being tested from the insulation detection circuit, limits the current in the detection circuit, and protects the detection circuit from damage. The switch control module includes a first control switch. Second control switch To control the on / off state of the insulation detection circuit; The current sensor includes a first current sensor. Second current sensor It is used to detect the current value in the circuit and provide real-time data for subsequent plotting of current waveforms to analyze the rising and falling edges of the current. The signal modulation circuit includes three The module performs current / voltage conversion, filtering, and amplification. The module is located between the current sensor and the processor. Located in the first coupling resistor On the processor branch, Located in the second coupling resistor On the processor branch; The processor is used to receive current sensor and The module's measurement data is used to calculate the resistive and capacitive components of the power transmission line's impedance to ground based on the three-point sampling method and the double-edge test method, and a warning signal is sent.

2. The insulation resistance and capacitance measurement circuit based on single-pulse dual-edge analysis as described in claim 1, characterized in that, The object being tested also includes the power supply voltage. First switch Second switch and load resistance Power supply voltage Load resistance The resistive component of the impedance to ground and the capacitive component of the impedance to ground are connected in parallel; the first switch Second switch Control the power supply voltage separately and load resistance The opening and closing of the branch circuit is achieved by controlling the different states of two switches, enabling expansion into multiple scenarios: When the first switch Second switch When both are disconnected, the power supply voltage and load resistance With the branch disconnected, the detection circuit is connected to both the resistive and capacitive components of the impedance to ground, used to detect the pure line impedance, and includes a first resistor. Second resistor First capacitor Second capacitor ; When the first switch Close, second switch When disconnected, the power supply voltage Branch circuit connected, load resistance Branch circuit disconnected, detection circuit and power supply voltage The resistive and capacitive components of the impedance to ground are connected to realize the voltage at the power supply terminals. Total insulation resistance Total insulation capacitance The joint testing, including total insulation resistance It is the first resistor Second resistor Parallel value, total insulation capacitance It is the first capacitor Second capacitor Parallel values; When the first switch Disconnect, second switch When closed, the power supply voltage Branch circuit disconnected, load resistance Branch connection, detection circuit and load resistor The resistive and capacitive components of the impedance to ground are connected to realize the load terminal voltage and the total insulation resistance. Total insulation capacitance Joint testing.

3. A method for measuring insulation resistance and capacitance based on single-pulse dual-edge analysis, characterized in that, The method is implemented using the insulation resistance and capacitance measurement circuit based on single-pulse dual-edge analysis as described in any one of claims 1-2, including: (1) A common-mode voltage pulse is injected into the transmission line of the power transmission system using a pulse transmitter, and then applied to the positive and negative busbars through a coupling resistor; (2) Real-time acquisition of pulse current response, plotting current waveform, and calculation of time constant using three-point sampling method. Record the current values ​​at three different times to measure the insulation resistance parameter; (3) Based on the load conditions, the dual-edge verification method is applied based on the pulse current attenuation characteristics. The insulation impedance parameters, including resistive and capacitive components, are calculated independently by analyzing the rising and falling edges of the pulse current.

4. The insulation resistance and capacitance measurement method based on single-pulse dual-edge analysis as described in claim 3, characterized in that, In step (2), the three-point sampling method is used to calculate the time constant: Record , and The first pulse current at time 1 , and ,set up The time constant is obtained by recording the current value. Represented as: in, , , This is the voltage value of the common-mode pulse voltage. This is the coupling resistor.

5. The insulation resistance and capacitance measurement method based on single-pulse dual-edge analysis as described in claim 3, characterized in that, In step (3), when the power transmission system is unloaded or lightly loaded, the insulation impedance parameters are calculated based on the rising edge of the pulse current using the three-point sampling method: Given coupling resistance and common-mode pulse voltage From the first pulse current Read the current value from the waveform , and steady-state current ,according to Calculate the total resistance : Therefore, the first resistance can be solved. : Based on the read current value , and The first resistance obtained by combining the calculation and known coupling resistance Further calculations yielded the first capacitor. : Coupling resistor and the first resistor Parallel pair Discharge, time constant Represented as: The time constant calculated in step (2) Substituting into the formula, we can obtain: Similarly, the three-point sampling method is used to measure the second pulse current. exist , and Current value at time , and Based on the known quantities, the second resistance can be calculated. With the second capacitor : 。 6. The insulation resistance and capacitance measurement method based on single-pulse dual-edge analysis as described in claim 3, characterized in that, In step (3), when the power transmission system is under heavy load, the load resistance... hour, and pass Forced parallel connection, analysis of the rising edge of the pulse current: The total current analysis method is used to detect the total loop current after injecting a common-mode pulse. : , and Let represent the first pulse current and the second pulse current, respectively. At this time, the coupling resistors are also in parallel, therefore the coupling resistance is . ,right The three-point sampling method is used to measure the total loop current. exist , and Current value at time , and Combined with the time constant calculated in step (2) Directly calculate the total insulation resistance Total insulation capacitance : in, This is the voltage value of the common-mode pulse voltage.

7. The insulation resistance and capacitance measurement method based on single-pulse dual-edge analysis as described in claim 3, characterized in that, In step (3), when the power transmission system is unloaded or lightly loaded, the falling edge of the pulse current is analyzed based on the three-point sampling method, and the insulation impedance parameters are recalculated to verify the measurement data: Select before the falling edge time Measure the first pulse current at all times , Selected and At that moment, and Measure the first pulse current and ; Based on the known common-mode pulse voltage and coupling resistor Solve for the first resistance. and the first capacitor : Similarly, the three-point sampling method is used to measure the second pulse current. At the falling edge , and Current value at time , and By combining the known quantities, the second resistance can be calculated. With the second capacitor :

8. The insulation resistance and capacitance measurement method based on single-pulse dual-edge analysis as described in claim 3, characterized in that, In step (3), when the power transmission system is heavily loaded or the power supply internal resistance is very small, the total current analysis method is used to analyze the falling edge of the pulse current: After injecting a common-mode pulse, the total loop current is detected. At this time, the coupling resistors are in parallel relationship. ,right Using the three-point sampling method, the falling edge time is selected. , and current value , and Directly calculate the total insulation resistance Total insulation capacitance : in, The voltage value is the common-mode pulse voltage; the impedance component is measured during the falling edge of the pulse current to avoid the instantaneous oscillation when the power is turned on; the results of the rising and falling edges of the pulse current are combined for cross-verification to reduce measurement error.

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