Relay protection transmission verification method and device based on potential monitoring

Abstract

The invention discloses a relay protection transmission verification method and device based on potential monitoring, and relates to the technical field of power system relay protection, and the method comprises the following steps: selecting a potential monitoring point between a relay protection tripping outlet pressing plate and a breaker tripping coil; under the condition that the circuit breaker is switched on and actual switching-off is forbidden, a tripping outlet pressing plate is put in, and a reference potential is collected; a relay protection tripping action signal is triggered, so that a tripping outlet loop forms a controlled electrical conduction state and does not drive the circuit breaker to be mechanically opened; potential changes of the potential monitoring points are collected, and action potential characteristics are obtained; and judging the conduction state from the tripping outlet to the circuit breaker tripping coil loop based on the corresponding relation between the reference potential and the action potential characteristic. According to the invention, on the premise of zero mechanical wear and no need of power failure, complete and reliable conductivity verification is carried out on the whole secondary loop from the protection outlet to the tripping coil, so that the hidden danger of protection operation refusal is effectively eliminated, and the test safety and the operation and maintenance economy are remarkably improved.

Description

A verification method and device for relay protection drive based on potential monitoring Technical Field

[0001] This invention relates to the field of power system relay protection technology, and more specifically, to a relay protection transmission verification method and device based on potential monitoring. Background Technology

[0002] Relay protection systems are the core guarantee for the safe and stable operation of power systems. To ensure the reliability and accuracy of relay protection device operation, transmission tests must be conducted before circuit breakers are officially put into operation or after routine inspections and upgrades of protection equipment. Traditional methods require actually driving the circuit breaker to open for each test to observe its operational behavior. However, frequent opening and closing operations will lead to accelerated wear of the circuit breaker's mechanical components, and long-term use may cause fatigue of mechanical components, affecting their service life and reliability. Frequent operations also increase the frequency of maintenance and component replacement, thereby increasing maintenance costs. In addition, during power system operation, there are often situations where some circuit breakers cannot be shut down due to power supply continuity requirements. When the protection devices and monitoring and control devices related to this circuit breaker need to be upgraded or verified, traditional transmission methods cannot be implemented because they involve the actual opening and closing of the circuit breaker.

[0003] To address the aforementioned issues, existing technologies have attempted to reduce the number of actual trips. For example, when verifying different protection functions, an actual trip is only performed on the first trip, with subsequent tests only checking whether the protection device internally issues an action signal. However, this method only verifies the protection device's own logical function and cannot verify the integrity of the secondary circuit (including pressure plate contact, wiring, relay contact condition, etc.) between the protection device's output relay contacts and the circuit breaker's trip coil. If this section of the circuit has defects such as open circuits or poor contact, the protection action command will not be able to truly reach the circuit breaker, posing a serious risk of protection failure to operate. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a relay protection transmission verification method and device based on potential monitoring. By actively establishing a controlled electrical conduction state in the trip output circuit under the condition that the actual tripping of the circuit breaker is prohibited, and simultaneously monitoring the potential characteristic changes of the potential monitoring points in the circuit under this state, a reliable conduction verification of the complete secondary circuit from the protection output to the circuit breaker trip coil can be achieved without mechanical wear or power outage. This solves the technical problems of high equipment loss, limited application, and safety hazards caused by incomplete verification in traditional methods.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a relay protection transmission verification method based on potential monitoring, comprising the following steps: selecting a secondary circuit node as a potential monitoring point between the relay protection trip output pressure plate and the circuit breaker trip coil; under the condition that the circuit breaker is closed and actual tripping is prohibited, engaging the trip output pressure plate and collecting the reference potential at the non-conductive potential monitoring point; triggering the relay protection trip action signal to form a controlled electrical conduction state in the trip output circuit without driving the circuit breaker to mechanically trip; collecting the potential change at the potential monitoring point during the trip action signal output period to obtain the action potential characteristics; and determining the conduction state of the circuit from the trip output to the circuit breaker trip coil based on the correspondence between the reference potential and the action potential characteristics, thus completing the transmission state verification.

[0006] In a preferred embodiment, the selection of the potential monitoring point specifically includes: injecting an auxiliary current signal with identifiable characteristics into the trip output circuit when the relay protection device is not activated; simultaneously measuring the voltage response of the lower terminal of the trip output pressure plate and the inlet terminal of the trip circuit to the auxiliary current signal; calculating the equivalent impedance of the circuit from each measurement point to the trip coil based on the voltage response; and selecting the node with the highest matching degree between the equivalent impedance of the circuit and the nominal impedance of the trip coil as the potential monitoring point.

[0007] In a preferred embodiment, the acquisition of the reference potential of the non-conductive potential monitoring point specifically includes: continuously sampling the potential of the potential monitoring point within a preset time period after the trip output pressure plate is engaged and before the protection action is triggered to obtain a reference potential sequence; performing statistical analysis on the reference potential sequence to extract its noise characteristics; coupling the noise characteristics with the system rated voltage to establish a dynamic reference potential range; and setting the upper boundary of the dynamic reference potential range as a dynamic judgment threshold for identifying a valid trip action.

[0008] In a preferred embodiment, establishing a dynamic reference potential interval specifically includes: performing sliding window sampling on the reference potential sequence within a preset time period, and performing a fast Fourier transform on the sampling points within each window to separate the power frequency component and the high-frequency noise component; calculating the noise intensity characteristic quantity within each window based on the high-frequency noise component, wherein the noise intensity characteristic quantity is the weighted average of the standard deviation and peak-to-peak value of the high-frequency noise component within that window; and inputting the system rated voltage and the noise intensity characteristic quantity into a predetermined interval generation function to calculate and generate the dynamic reference potential interval.

[0009] In a preferred embodiment, the process of forming a controlled electrical conduction state without driving the circuit breaker to mechanically trip includes: connecting a high-impedance injection unit in parallel to the branch where the potential monitoring point is located, and injecting a trigger signal lower than the minimum operating current threshold of the circuit breaker into the branch; simultaneously sending a blocking control signal to the circuit breaker operating mechanism to prohibit it from mechanically tripping during the trigger signal injection period; during the duration of the trigger signal, simultaneously acquiring the current signal flowing through the branch and the electromagnetic field change signal generated by the relay operation; when both the current signal and the electromagnetic field change signal meet the preset action criteria, determining that the trip output circuit has formed a controlled electrical conduction state.

[0010] In a preferred embodiment, the method for determining whether both the current signal and the electromagnetic field change signal satisfy the preset action criteria specifically includes: extracting the rate of change of current and the rate of change of magnetic field from the current signal and the electromagnetic field change signal, respectively; calculating the ratio between the rate of change of current and the rate of change of magnetic field as a dynamic physical coupling coefficient; comparing the dynamic physical coupling coefficient with a pre-stored standard coupling coefficient reference value that characterizes the standard operating state of the trip output relay; and determining that both the current signal and the electromagnetic field change signal satisfy the preset action criteria if the deviation between the dynamic physical coupling coefficient and the standard coupling coefficient is within a preset error range.

[0011] In a preferred embodiment, obtaining the action potential feature specifically includes: triggering and capturing the potential change waveform of the potential monitoring point based on the dynamic determination threshold; extracting at least one time-domain feature parameter from the potential change waveform to characterize its change relative to the reference potential, as the action potential feature; the time-domain feature parameter includes the absolute change amount and the change duration of the potential change waveform.

[0012] In a preferred embodiment, determining the conduction state of the circuit from the trip output to the circuit breaker trip coil specifically includes: calculating an action energy evaluation value characterizing the integrity of the current action process based on the absolute change and duration of the change in the action potential characteristics; comparing the action energy evaluation value with a pre-stored standard action energy threshold; and if the deviation between the action energy evaluation value and the standard action energy threshold is within the allowable range, then the circuit action process is preliminarily determined to be complete.

[0013] In a preferred embodiment, based on the preliminary determination, the event timing logic verification is further included: based on the synchronously acquired current signal, electromagnetic field change signal, and potential change waveform, the following state switching timing logic is verified: the start time of the electromagnetic field change signal is earlier than the start time of the rising edge of the potential change waveform; the effective establishment time of the current signal is synchronized with the start time of the rising edge of the potential change waveform; the time when the potential change waveform falls back to the steady-state platform is later than the end time of the trigger signal; when the action energy evaluation value meets the requirements and the event timing logic is verified, it is determined that the circuit from the trip output to the circuit breaker trip coil has formed an effective conducting state.

[0014] The apparatus for a relay protection transmission verification method based on potential monitoring includes: a monitoring point optimization unit, used to select a secondary circuit node as a potential monitoring point between the relay protection trip output pressure plate and the circuit breaker trip coil; a reference learning unit, used to engage the trip output pressure plate and collect the reference potential of the non-conductive potential of the potential monitoring point under the condition that the circuit breaker is closed and actual tripping is prohibited; a safety excitation unit, used to trigger the relay protection trip action signal to form a controlled electrical conduction state in the trip output circuit without driving the circuit breaker to mechanically trip; a feature extraction unit, used to collect the potential change of the potential monitoring point during the trip action signal output to obtain the action potential characteristics; and a decision output unit, used to determine the conduction state of the circuit from the trip output to the circuit breaker trip coil based on the correspondence between the reference potential and the action potential characteristics, thus completing the transmission state verification.

[0015] The technical effects and advantages of the relay protection transmission verification method and device based on potential monitoring of the present invention are as follows: 1. The present invention enables the trip output circuit to form a controlled electrical conduction state without driving the circuit breaker to mechanically open under the condition that the circuit breaker is closed and actual opening is prohibited. This allows the transmission verification to be completed without actually disconnecting the circuit breaker, avoiding the wear and fatigue of mechanical parts caused by actually driving the circuit breaker to open in the traditional method, extending the service life of the equipment, reducing maintenance costs, and making it possible to perform uninterrupted transmission verification under the condition that the circuit breaker is closed. This solves the problem that traditional transmission tests cannot be carried out under the requirement of power supply continuity.

[0016] 2. This invention establishes a correspondence between the non-conductive reference potential of the potential monitoring point and the action potential characteristics obtained by collecting the potential changes of the potential monitoring point during the trip action signal output. Based on this, the continuity status of the circuit from the trip output to the circuit breaker trip coil is determined. It does not rely on the external mechanical action of the circuit breaker, but directly verifies its continuity by monitoring and analyzing the potential changes of key nodes inside the secondary circuit. This effectively detects the continuity status of all secondary circuits (including pressure plates, wiring, and contacts) from the trip output to the trip coil, solving the defect of existing methods that only check the protection device signal and cannot verify the integrity of the secondary circuit, thus eliminating the hidden danger of protection failure to operate. Attached Figure Description

[0017] Figure 1 is a flowchart illustrating a relay protection transmission verification method based on potential monitoring according to the present invention; Figure 2 is a schematic diagram illustrating the device structure of a relay protection transmission verification method based on potential monitoring according to the present invention; Figure 3 is a simplified diagram of the control circuit of the protection device; Figure 4 is a flowchart illustrating the selection of potential monitoring points. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1, Figure 1 shows a relay protection transmission verification method based on potential monitoring according to the present invention, including the following steps: S1, selecting a secondary circuit node as a potential monitoring point between the relay protection trip output pressure plate and the circuit breaker trip coil; it should be noted that, in this embodiment, in order to achieve effective monitoring of the conduction state of the trip output circuit, it is first necessary to determine an optimal potential monitoring point in the circuit. This potential monitoring point should be located between the relay protection trip output pressure plate and the circuit breaker trip coil to ensure that the circuit potential change caused by the protection action can be accurately captured. In order to overcome the problem that the traditional method of selecting the monitoring point based on experience may lead to signal attenuation or distortion (e.g., due to abnormal contact resistance in the circuit), the present invention provides a selection method, the process of which is shown in Figure 4.

[0020] In this embodiment, the selection of the potential monitoring point specifically includes: S11, when the relay protection device does not operate, injecting an auxiliary current signal with identifiable characteristics into the trip output circuit; under the safe premise of ensuring that the relay protection device does not operate and the circuit breaker is in the closed state, injecting an auxiliary current signal with identifiable characteristics into the trip output circuit to be tested. The signal is preferably a DC pulse signal with a constant amplitude (e.g., 5mA), a frequency different from the power frequency (e.g., 125Hz), or a specific coded sequence, to facilitate extraction from complex background noise. In practice, the signal can be injected through a high-precision programmable current source, whose output is connected in parallel to a conveniently accessible test point in the trip output circuit.

[0021] Simultaneously, using two high-input-impedance voltage measuring devices (such as differential probes), the voltage response between the lower terminal of the trip output pressure plate and the trip circuit inlet terminal of the circuit breaker operating box to the common reference ground is measured, and recorded as follows: and Measurements are performed within the same time window to ensure data comparability.

[0022] Simultaneously measure the voltage response of the lower terminal of the trip output pressure plate and the inlet terminal of the trip circuit to the auxiliary current signal; S12, based on the voltage response, calculate the equivalent circuit impedance from each measurement point to the trip coil, the specific steps are as follows: according to the circuit principle, the equivalent circuit impedance from the measurement point to the trip coil direction... The equivalent impedance of the circuit for the lower terminal of the trip outlet pressure plate can be calculated using Ohm's law. :

[0023] Similarly, the equivalent impedance of the circuit at the inlet terminal of the trip circuit can be calculated. .

[0024] It should be noted that the calculation in this embodiment... and It is the magnitude of the complex impedance, which includes not only the DC resistance of the trip coil, but also the sum of the contact resistances of all connecting wires, terminals, and auxiliary switch contacts from the measurement point to the coil, as well as the influence of distributed parameters. Under DC or low-frequency injection conditions, the equivalent impedance of the circuit can be approximated as a real impedance.

[0025] S13, select the node with the highest matching degree between the circuit equivalent impedance and the nominal impedance of the trip coil as the potential monitoring point.

[0026] Obtain the nominal impedance of the circuit breaker's trip coil (This is typically the DC resistance value of the coil, which can be obtained from the equipment nameplate or technical manual.) Calculate the equivalent impedance of each circuit. and With nominal impedance The matching degree M is used to select nodes with higher matching degrees as the final potential monitoring points. The matching degree can be measured by the reciprocal of the relative error or by setting an error function. A preferred and simple calculation method is:

[0027] This invention, by actively injecting an auxiliary current signal and calculating the equivalent impedance of the circuit, can identify and avoid abnormally high resistance points (such as poorly contacted pressure plates or terminals) in the circuit, ensuring that the electrical connection between the selected potential monitoring point and the trip coil is the most direct and has the lowest impedance, thus laying the optimal measurement foundation for subsequent high-fidelity acquisition of action potential characteristics.

[0028] S2, Under the condition that the circuit breaker is closed and actual opening is prohibited, the trip output pressure plate is engaged, and the reference potential of the non-conductive potential monitoring point is collected. In this embodiment, the collection of the reference potential of the non-conductive potential monitoring point specifically includes: S21, within a preset time period after the trip output pressure plate is engaged and before the protection action is triggered, the potential of the potential monitoring point is continuously sampled to obtain a reference potential sequence; Under the condition that the circuit breaker is closed and actual opening is prohibited, the trip output pressure plate is engaged, and the potential to ground of the potential monitoring point is continuously sampled using a high-precision analog-to-digital converter (ADC). The sampling frequency should be much higher than the possible interference frequency (e.g., not less than 10 kS / s). The sampling is continuously performed for a preset time period. (e.g., 2-5 seconds) to obtain a reference potential sequence .

[0029] S22, perform statistical analysis on the reference potential sequence to extract its noise characteristics; the reference potential sequence can be divided into multiple time-continuous sliding windows, each containing a fixed number of sampling points, and perform Fast Fourier Transform (FFT) on the reference potential data in each sliding window to decompose the potential signal into power frequency components and high-frequency noise components, wherein the high-frequency noise components mainly reflect on-site electromagnetic interference, measurement system noise and small circuit disturbances.

[0030] Based on the high-frequency noise components, their statistical characteristic parameters, including but not limited to standard deviation, are calculated respectively. and peak value The parameters are then weighted and combined to obtain the noise intensity feature of the corresponding window. .

[0031] S23, couple noise characteristics with system rated voltage to establish a dynamic reference potential range; combine power system rated voltage and noise intensity characteristic quantity The dynamic reference potential range is calculated using a predetermined interval generation function. A preferred function form is:

[0032]

[0033] in, and The tolerance factor is set according to the system's immunity requirements, typically .

[0034] S24, the upper boundary of the calculated dynamic reference potential range. It is directly set as a dynamic threshold for subsequent determination of whether a tripping action has occurred. ,Right now .

[0035] S3 triggers a relay protection trip signal, causing the trip output circuit to form a controlled electrical conduction state without driving the circuit breaker to mechanically open. In this embodiment, forming a controlled electrical conduction state specifically includes: S31, connecting a high-impedance injection unit in parallel in the branch where the potential monitoring point is located. This unit can be composed of a high-power, high-resistance resistor (e.g., 100kΩ) and a high-speed solid-state relay connected in series. Through the high-impedance injection unit, a trigger signal with an amplitude lower than the minimum operating current threshold of the circuit breaker is injected into the branch where the potential monitoring point is located. .

[0036] Sending a trigger signal At the same time, a forced interlocking control signal is sent to the circuit breaker's operating mechanism, driving an interlocking electromagnet to physically prevent the circuit breaker's tripping mechanism from operating during the trigger signal injection period, thus achieving double safety protection.

[0037] Trigger signal During the continuous operation, the current signal flowing through the branch is acquired by a high-precision shunt or closed-loop Hall sensor connected in series in the branch. By attaching a high-frequency magnetoresistive sensor to the surface of the trip relay housing, the electromagnetic field change signal generated by the relay operation is collected. The potential of the potential monitoring point is collected. .

[0038] S32, to ensure the data collection and If the interference is indeed generated by the target relay (rather than external interference), verification is required, specifically: [The following is a list of steps to be performed] and Perform first-order differential operations to extract the rate of change, calculate the real-time ratio of the rate of change, and obtain the dynamic physical coupling coefficient. :

[0039] Dynamic physical coupling coefficient The average value during the operating period and the pre-stored standard coupling coefficient reference value that characterizes the standard operating state of the trip output relay. If the deviation between the dynamic physical coupling coefficient and the standard coupling coefficient is within a preset error range, then it is determined that both the current signal and the electromagnetic field change signal meet the preset action criteria, and the trigger signal is confirmed. The physical action of the target relay was actually triggered, and the trip output circuit formed a controlled electrical conduction state.

[0040] The standard coupling coefficient reference value Electromagnetic calculations can be performed based on the coil inductance, core material, and geometry of this relay model, or multiple standard operation tests can be conducted on a sample of this health relay model in the laboratory to statistically analyze its performance. The average value is obtained.

[0041] S4, during the tripping action signal output, the potential change at the potential monitoring point is collected to obtain the action potential characteristics; in this embodiment, obtaining the action potential characteristics specifically includes: using a dynamic determination threshold. As a triggering condition, when the potential First time from below leap up and surpass At that time, lock that moment as the starting point of the action. Using this as the center, extend the waveform forward and backward by a predefined time interval (e.g., 5ms before and 20ms after) to capture the potential change waveform that includes the complete rise edge and steady-state process. .

[0042] From the potential change waveform In this process, at least one time-domain feature parameter characterizing its change relative to the reference potential is extracted, including the absolute change amount and the duration of the change in the potential change waveform. The absolute change amount... Waveform of potential change Midpoint maximum value and reference potential (reference potential sequence can be selected) The difference between the median or mean of the two values, and the duration of the change. ,in, It is the first decrease and stabilization below the dynamic judgment threshold after the potential falls from its maximum value. At that moment.

[0043] From absolute change and duration of change This constitutes the characteristics of an action potential.

[0044] S5, based on the correspondence between the reference potential and the operating potential characteristics, determines the conduction state of the circuit from the trip output to the circuit breaker trip coil circuit, and completes the transmission state verification.

[0045] In this embodiment, determining the conduction state of the circuit from the trip output to the circuit breaker trip coil specifically includes: This embodiment uses the absolute change... and duration of change By integrating these components, an equivalent evaluation quantity (action energy evaluation value) is constructed to characterize the integrity of the action process. This evaluation value is not physical energy in the strict sense, but a quantitative indicator used to reflect the level of integrity of the loop conduction process.

[0046] S51, the motion energy evaluation value The calculation formula is:

[0047] in, This is an estimated value of the equivalent resistance of the circuit viewed from the potential monitoring point towards the trip coil. It can be obtained by calculating the equivalent impedance of the circuit. The actual part is obtained.

[0048] Motion energy evaluation value With a pre-stored standard motion energy threshold (This can be obtained through theoretical calculations or statistical analysis of calibration tests on healthy circuits) A comparison should be made to set an allowable range of relative error. (For example, ±20%), if the following conditions are met:

[0049] Therefore, it can be preliminarily determined that the operation process from the trip output to the circuit breaker trip coil circuit is complete.

[0050] S52, based on the preliminary judgment, in order to further eliminate misjudgments caused by interference, sporadic signals or non-real actions, this embodiment introduces event timing logic verification across physical quantities.

[0051] Logic 1: Electromagnetic field change signal The start of the transition It must be earlier than the potential. rising edge start time This is used to verify that the physical response of a relay electromagnetic actuator occurs before the change in circuit potential.

[0052] Logic 2: Current signal Effective establishment time (defined as) (the moment when it rises to 90% of its steady-state value) must be compared with... The phases are basically synchronized, with a difference of no more than 2ms between the start and end times, which is used to verify that the current establishment and potential change have a causal synchronous relationship.

[0053] Logic 3: Potential The moment when, after falling from the peak, it first stabilizes at a certain plateau value. It must be later than the trigger signal. The end time This is used to verify that the circuit potential change completely covers the trigger signal's action period.

[0054] The circuit from the trip output to the circuit breaker trip coil is determined to be in an effective conducting state if and only if the action energy evaluation value meets the requirements and the event timing logic is verified, and the transmission state verification is passed.

[0055] Example 2, Figure 2 shows an apparatus for a relay protection transmission verification method based on potential monitoring, comprising: a monitoring point optimization unit, used to select a secondary circuit node as a potential monitoring point between the relay protection trip output pressure plate and the circuit breaker trip coil; a reference learning unit, used to engage the trip output pressure plate and collect the reference potential of the non-conductive potential monitoring point when the circuit breaker is closed and actual tripping is prohibited; a safety excitation unit, used to trigger the relay protection trip action signal to form a controlled electrical conduction state in the trip output circuit without driving the circuit breaker to mechanically trip; a feature extraction unit, used to collect the potential change of the potential monitoring point during the trip action signal output to obtain the action potential characteristics; and a decision output unit, used to determine the conduction state of the circuit from the trip output to the circuit breaker trip coil based on the correspondence between the reference potential and the action potential characteristics, thus completing the transmission state verification.

[0056] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0057] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0058] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0059] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0060] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0061] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A relay protection transmission verification method based on potential monitoring, characterized in that, Includes the following steps: A secondary circuit node is selected as a potential monitoring point between the relay protection trip output pressure plate and the circuit breaker trip coil; under the condition that the circuit breaker is closed and actual tripping is prohibited, the trip output pressure plate is engaged, and the reference potential of the potential monitoring point is collected when it is not conducting; the relay protection trip action signal is triggered, so that the trip output circuit forms a controlled electrical conduction state without driving the circuit breaker to mechanically trip. During the tripping action signal output, the potential change at the potential monitoring point is collected to obtain the action potential characteristics; Based on the correspondence between the reference potential and the operating potential characteristics, the conduction state of the circuit from the trip output to the circuit breaker trip coil is determined, and the transmission state verification is completed.

2. The relay protection transmission verification method based on potential monitoring according to claim 1, characterized in that, The selection of the potential monitoring point specifically includes: injecting an auxiliary current signal with identifiable characteristics into the trip output circuit when the relay protection device does not operate; simultaneously measuring the voltage response of the lower terminal of the trip output pressure plate and the inlet terminal of the trip circuit to the auxiliary current signal; calculating the equivalent impedance of the circuit from each measurement point to the trip coil based on the voltage response, and selecting the node with the highest matching degree between the equivalent impedance of the circuit and the nominal impedance of the trip coil as the potential monitoring point.

3. The relay protection transmission verification method based on potential monitoring according to claim 2, characterized in that, The acquisition of the reference potential of the non-conductive potential monitoring point specifically includes: continuously sampling the potential of the potential monitoring point within a preset time period after the trip output pressure plate is engaged and before the protection action is triggered to obtain a reference potential sequence; performing statistical analysis on the reference potential sequence to extract its noise characteristics; coupling the noise characteristics with the system rated voltage to establish a dynamic reference potential range; and setting the upper boundary of the dynamic reference potential range as a dynamic judgment threshold for identifying valid trip actions.

4. The relay protection transmission verification method based on potential monitoring according to claim 3, characterized in that, The establishment of the dynamic reference potential interval specifically includes: sampling the reference potential sequence through a sliding window within a preset time period, and performing a fast Fourier transform on the sampling points within each window to separate the power frequency component and the high-frequency noise component; calculating the noise intensity characteristic quantity within each window based on the high-frequency noise component, wherein the noise intensity characteristic quantity is the weighted average of the standard deviation and peak-to-peak value of the high-frequency noise component within that window; and inputting the system rated voltage and the noise intensity characteristic quantity into a predetermined interval generation function to calculate and generate the dynamic reference potential interval.

5. The relay protection transmission verification method based on potential monitoring according to claim 4, characterized in that, The process of establishing a controlled electrical conduction state without driving the circuit breaker to mechanically trip includes: connecting a high-impedance injection unit in parallel to the branch where the potential monitoring point is located, and injecting a trigger signal lower than the minimum operating current threshold of the circuit breaker into the branch; simultaneously sending a blocking control signal to the circuit breaker operating mechanism to prohibit it from mechanically tripping during the trigger signal injection period; during the duration of the trigger signal, simultaneously acquiring the current signal flowing through the branch and the electromagnetic field change signal generated by the relay operation; when both the current signal and the electromagnetic field change signal meet the preset action criteria, determining that the trip output circuit has formed a controlled electrical conduction state.

6. The relay protection transmission verification method based on potential monitoring according to claim 5, characterized in that, The method for determining whether both the current signal and the electromagnetic field change signal meet the preset action criteria specifically includes: extracting the rate of change of current and the rate of change of magnetic field from the current signal and the electromagnetic field change signal respectively; calculating the ratio between the rate of change of current and the rate of change of magnetic field as a dynamic physical coupling coefficient; comparing the dynamic physical coupling coefficient with a pre-stored standard coupling coefficient reference value that characterizes the standard operating state of the trip output relay; if the deviation between the dynamic physical coupling coefficient and the standard coupling coefficient is within a preset error range, then determining that both the current signal and the electromagnetic field change signal meet the preset action criteria.

7. The relay protection transmission verification method based on potential monitoring according to claim 6, characterized in that, The acquisition of action potential features specifically includes: triggering and capturing the potential change waveform of the potential monitoring point based on the dynamic determination threshold; extracting at least one time-domain feature parameter from the potential change waveform to characterize its change relative to the reference potential, as the action potential feature; the time-domain feature parameter includes the absolute change amount and the change duration of the potential change waveform.

8. The relay protection transmission verification method based on potential monitoring according to claim 7, characterized in that, The determination of the conduction status of the circuit from the trip output to the circuit breaker trip coil specifically includes: calculating the action energy evaluation value characterizing the integrity of the current action process based on the absolute change and duration of the change in the action potential characteristics; comparing the action energy evaluation value with the pre-stored standard action energy threshold; if the deviation between the action energy evaluation value and the standard action energy threshold is within the allowable range, the circuit action process is initially determined to be complete.

9. The relay protection transmission verification method based on potential monitoring according to claim 8, characterized in that, Based on the preliminary judgment, the event timing logic verification is further included: based on the synchronously acquired current signal, electromagnetic field change signal and potential change waveform, the following state switching timing logic is verified: the start time of the electromagnetic field change signal is earlier than the start time of the rising edge of the potential change waveform; the effective establishment time of the current signal is synchronized with the start time of the rising edge of the potential change waveform. The moment when the potential change waveform falls back to the steady-state platform is later than the end time of the trigger signal; when the action energy evaluation value meets the requirements and the event timing logic is verified, it is determined that the circuit from the trip output to the circuit breaker trip coil has formed an effective conduction state.

10. An apparatus for verifying relay protection transmission based on potential monitoring as described in any one of claims 1-9, characterized in that, include: The monitoring point optimization unit is used to select a secondary circuit node as a potential monitoring point between the relay protection trip output pressure plate and the circuit breaker trip coil. The reference learning unit is used to engage the trip output pressure plate and collect the reference potential when the potential monitoring point is not conducting under the condition that the circuit breaker is closed and actual tripping is prohibited. The safety excitation unit is used to trigger the relay protection trip action signal, so that the trip output circuit forms a controlled electrical conduction state without driving the circuit breaker to mechanically open. The feature extraction unit is used to collect the potential changes at the potential monitoring point during the trip action signal output to obtain the action potential characteristics; The decision output unit is used to determine the conduction state of the circuit from the trip output to the circuit breaker trip coil circuit based on the correspondence between the reference potential and the operating potential characteristics, and to complete the transmission state verification.

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