A method and system for rapid short-circuit current detection and alarm in feeder terminals

Abstract

This invention provides a method and system for rapid short-circuit current identification and alarm for feeder terminals, relating to the field of cable line monitoring technology. The method includes: real-time acquisition of instantaneous sampled data of the feeder current, calculation of the current amplitude change rate, phasor extraction, calculation of the current phase value, construction of a phase transient characteristic quantity using the phase difference of continuous time sampling points, coupling analysis of the first-order amplitude change quantity and the phase transient characteristic quantity to construct a short-circuit characteristic coupling indicator, triggering an abnormal reporting command for a short-circuit event when the short-circuit characteristic coupling indicator exceeds a preset coupling threshold, determining the rapid alarm level of the short-circuit event based on the trigger time and the duration of the phase transient characteristic quantity, and issuing alarm information to the main station. This solves the technical problem of low accuracy and reliability in short-circuit current identification of feeder terminals in existing technologies. It achieves rapid identification and alarm of short-circuit current events in feeder terminals while improving the accuracy and reliability of the identification.

Description

Technical Field

[0001] This invention relates to the field of cable line monitoring technology, specifically to a method and system for rapid short-circuit current identification and alarm for feeder terminals. Background Technology

[0002] Feeder terminals are key equipment in distribution network automation, mainly used for measuring and monitoring electrical parameters such as current and voltage, as well as detecting and controlling fault events. Feeders are the main carriers of load and power supply tasks in the distribution network, used to transmit electrical energy from substations to the user end.

[0003] With the integration of distributed power sources, rapid load changes, and the increasing complexity of distribution network structures, feeder current fluctuations exhibit short-term, drastic changes and frequent disturbances. Current technologies for feeder short-circuit current detection primarily rely on fixed thresholds or single characteristic quantities. By setting a current amplitude threshold, a short-circuit fault is identified when the detected current exceeds the threshold. This approach, based on a single threshold characteristic, lacks a comprehensive analysis of fault characteristics, cannot accurately distinguish short-circuit events from other disturbances, and is prone to misjudgments and missed detections, thus reducing the accuracy and reliability of the detection.

[0004] The existing technology for determining the short-circuit current of feeder terminals suffers from low accuracy and reliability. Summary of the Invention

[0005] The purpose of this application is to provide a method and system for rapid short-circuit current identification and alarm for feeder terminals, in order to solve the technical problems of low accuracy and reliability in the short-circuit current identification of feeder terminals in the prior art.

[0006] In view of the above problems, this application provides a method and system for rapid short-circuit current identification and alarm for feeder terminals.

[0007] The first aspect of this application provides a method for rapid short-circuit current detection and alarm for feeder terminals. The method includes: acquiring instantaneous sampling data of feeder current in real time; calculating the rate of change of current amplitude based on adjacent sampling points of the instantaneous sampling data to obtain a first-order amplitude change quantity used to characterize the degree of current abrupt change; extracting phasors from the instantaneous sampling data within the same sampling period to calculate the current phase value; constructing a phase transient characteristic quantity using the phase difference of continuous time sampling points, the phase transient characteristic quantity including the maximum amplitude of phase jump, the short-window phase mean square error, and the phase jump direction; performing coupling analysis on the first-order amplitude change quantity and the phase transient characteristic quantity to construct a short-circuit characteristic coupling indicator, the short-circuit characteristic coupling indicator being used to characterize the synchronicity of amplitude jump and phase shift caused by impedance drop due to short circuit; when the short-circuit characteristic coupling indicator exceeds a preset coupling threshold, triggering an abnormal reporting command for a short-circuit event; determining the rapid alarm level of the short-circuit event based on the trigger time and the duration of the phase transient characteristic quantity; and issuing alarm information to the main station.

[0008] Optionally, the original phase sequence of continuous time sampling points is subjected to phase expansion processing to eliminate the backtracking from -π to π, making the phase sequence continuous; the phase difference between adjacent sampling points of the expanded phase sequence is calculated to form a basic transient phase change sequence; a sliding short window statistical analysis is performed on the basic transient phase change sequence, the maximum amplitude of the phase jump is generated based on the maximum phase difference within the sliding short window, the root mean square value of the phase difference within the sliding short window is generated to form the short window phase mean square error, and the phase jump direction is generated based on the sign of the phase difference before and after the maximum amplitude point; a phase transient feature quantity is constructed based on the maximum amplitude of the phase jump, the short window phase mean square error, and the phase jump direction.

[0009] Optionally, the first-order amplitude change is normalized to establish an amplitude jump feature; the phase transient feature is weighted and calibrated, and the maximum amplitude of the phase jump, the short-window phase mean square error, and the phase jump direction are mapped to normalized feature components to establish a unified transient feature vector; a coupling discriminant function is constructed based on the synchronicity of the amplitude jump feature and the transient feature vector, and the instantaneous peak value of the amplitude change is matched with the corresponding time point of the transient feature vector to calculate the coupling score; the coupling score is output as a short-circuit feature coupling indicator.

[0010] Optionally, a temporal stability evaluation is performed on transient feature vectors within three or more consecutive sampling periods. If the direction of change of the transient feature vector remains consistent at the moment corresponding to the peak amplitude jump, and the time alignment offset of the amplitude change and phase change does not exceed the preset stability range, it is recorded as a stable period, and the coupling discrimination function is allowed to output a coupling score.

[0011] Optionally, if the change direction of the amplitude jump peak and the time alignment offset of the amplitude change and phase change do not meet the requirements, it is recorded as an unstable period and will not enter the short circuit event triggering process.

[0012] Optionally, based on the trigger time, instantaneous sampling data and half-cycle synchronous sampling data within the same period are extracted simultaneously, and the corresponding phase difference and amplitude change amount are calculated respectively to form a verification sampling pair; the verification sampling pair is used to construct a time delay consistency index, and the differences between instantaneous sampling and synchronous sampling in phase change direction, phase jump amplitude, and amplitude rise degree are compared by time alignment; a micro-time delay consistency index is calculated based on the phase change direction, a difference index is established based on the phase jump amplitude, and a response consistency index is calculated based on the amplitude rise degree; the validity judgment and management of short-circuit events are performed based on the micro-time delay consistency index, difference index, and response consistency index.

[0013] Optionally, when the micro-latency consistency index is within a preset directional consistency range, the difference index is lower than a set amplitude deviation threshold, and the response consistency index exceeds the lower limit threshold of response consistency, the short circuit event is determined to be valid; after determining the rapid alarm level of the short circuit event, an alarm message is sent to the main station.

[0014] Optionally, if any one of the micro-latency consistency index, difference index, and response consistency index fails, the short-circuit event is deemed invalid. A suspicious short-circuit event identifier is configured based on the degree of suspicion of the index, and the suspicious short-circuit event identifier is used to trigger a secondary sampling verification within a short time window.

[0015] Optionally, an early warning verification window is established based on the alarm information; alarm processing verification of short circuit events is performed in the early warning verification window, and verification management is executed.

[0016] A second aspect of this application provides a rapid short-circuit current detection and alarm system for feeder terminals. The system includes: a data calculation module for acquiring instantaneous sampled data of the feeder current in real time, calculating the rate of change of current amplitude based on adjacent sampling points of the instantaneous sampled data, and obtaining a first-order amplitude change quantity characterizing the degree of current abrupt change; and a feature quantity construction module for extracting phasors from the instantaneous sampled data within the same sampling period, calculating the current phase value, and constructing a phase transient feature quantity using the phase difference between continuous time sampling points, wherein the phase transient feature quantity includes the maximum phase jump. The system includes: an amplitude, short-window phase mean square error, and phase jump direction; a coupling analysis module, used to perform coupling analysis on the first-order amplitude change and the phase transient characteristic, to construct a short-circuit characteristic coupling indicator, which characterizes the synchronicity of the amplitude jump and phase shift caused by the impedance drop due to a short circuit; and an anomaly alarm module, used to trigger an anomaly reporting command for a short-circuit event when the short-circuit characteristic coupling indicator exceeds a preset coupling threshold, determine the rapid alarm level of the short-circuit event based on the trigger time and the duration of the phase transient characteristic, and issue alarm information to the main station.

[0017] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0018] The method provided in this application acquires instantaneous sampling data of feeder current in real time, calculates the rate of change of current amplitude based on adjacent sampling points of the instantaneous sampling data, and obtains a first-order amplitude change quantity to characterize the degree of current abrupt change; within the same sampling period, phasor extraction is performed on the instantaneous sampling data to calculate the current phase value, and a phase transient characteristic quantity is constructed using the phase difference of continuous time sampling points. The phase transient characteristic quantity includes the maximum amplitude of phase jump, the short-window phase mean square error, and the phase jump direction; the first-order amplitude change quantity and the phase transient characteristic quantity are coupled and analyzed to construct a short-circuit characteristic coupling indicator. The short-circuit characteristic coupling indicator is used to characterize the synchronicity of amplitude jump and phase shift caused by impedance drop due to short circuit; when the short-circuit characteristic coupling indicator exceeds a preset coupling threshold, an abnormal reporting command for a short-circuit event is triggered. Based on the trigger time and the duration of the phase transient characteristic quantity, the rapid alarm level of the short-circuit event is determined, and alarm information is issued to the main station. This achieves the technical effect of rapidly identifying and alarming short-circuit current events in feeder terminals while improving the accuracy and reliability of the identification.

[0019] The above description is merely an overview of the technical solution of this application. To enable a clearer understanding of the technical means of this application and to facilitate its implementation according to the description, and to make the above and other objects, features, and advantages of this application more apparent, specific embodiments of this application are described below. It should be understood that the content described in this section is not intended to identify key or important features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent through the following description. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a flowchart illustrating the method for rapid short-circuit current detection and alarm for feeder terminals provided in this application.

[0022] Figure 2 This is a schematic diagram of the structure of the short-circuit current rapid identification and alarm system for feeder terminals provided in this application.

[0023] Figure labeling: Data calculation module 11, feature quantity construction module 12, coupling analysis module 13, anomaly alarm module 14. Detailed Implementation

[0024] This application provides a method and system for rapid short-circuit current identification and alarm for feeder terminals, addressing the technical problems of low accuracy and reliability in short-circuit current identification of feeder terminals in existing technologies. It achieves the technical effect of rapidly identifying and alarming short-circuit current events in feeder terminals while improving the accuracy and reliability of the identification.

[0025] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be understood that the present invention is not limited to the exemplary embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. It should also be noted that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, not all of them.

[0026] Example 1, as Figure 1As shown, this application provides a method for rapid short-circuit current determination and alarm for feeder terminals, the method comprising:

[0027] Real-time sampling data of feeder current is acquired, and the rate of change of current amplitude is calculated based on adjacent sampling points of the instantaneous sampling data to obtain a first-order amplitude change quantity used to characterize the degree of current abrupt change.

[0028] Specifically, the feeder current is acquired in real time through a current transformer and an analog-to-digital converter (ADC) built into the feeder terminal. The current transformer is installed at key nodes of the feeder, such as the feeder outlet and branch points, to convert large currents in the feeder into smaller currents according to a certain ratio, accurately reflecting the current data at the acquisition location. The ADC is used to convert the analog current signal output by the current transformer into a digital signal. For example, the feeder current is acquired through the current transformer using a sampling frequency of 4kHz-20kHz, and the data is converted by the ADC to obtain instantaneous sampling data, which includes the instantaneous current value and the sampling timestamp.

[0029] Based on instantaneous sampling data, the current amplitude at adjacent sampling points is differentially calculated to determine the rate of change of current amplitude. Adjacent sampling points refer to the data points corresponding to two closely connected sampling times in the instantaneous sampling data time series; for example, at time t... n The current sampling value at time I n , t n+1 The current sampling value at time I n+1 The difference between the current amplitudes of these two adjacent sampling points is calculated using I. n+1 -I n The rate of change of current amplitude is obtained and used as a first-order amplitude change quantity to characterize the degree of current abrupt change, reflecting the drastic change of current in a short period of time. When a short-circuit fault occurs in the feeder, the current jumps sharply, and the first-order amplitude change quantity will increase significantly.

[0030] Within the same sampling period, phasor extraction is performed on the instantaneous sampled data to calculate the current phase value. The phase transient characteristic is constructed using the phase difference of continuous time sampling points. The phase transient characteristic includes the maximum amplitude of phase jump, the short-window phase mean square error, and the phase jump direction.

[0031] Furthermore, phase transient feature quantities are constructed using the phase difference of continuous time sampling points, including: performing phase expansion processing on the original phase sequence of continuous time sampling points to eliminate the reflection from -π to π, making the phase sequence continuous; calculating the phase difference between adjacent sampling points of the expanded phase sequence to form a basic transient phase change sequence; performing sliding short-window statistical analysis on the basic transient phase change sequence, generating the maximum amplitude of the phase jump based on the maximum phase difference within the sliding short window, generating the root mean square error of the short-window phase based on the root mean square value of the phase difference within the sliding short window, and determining the phase jump direction based on the sign of the phase difference before and after the maximum amplitude point; and constructing phase transient feature quantities based on the maximum amplitude of the phase jump, the root mean square error of the short-window phase, and the phase jump direction.

[0032] Specifically, within the same sampling period, a discrete-time sequence is constructed from consecutive instantaneous sampling points according to the sampling time. Using a Fast Fourier Transform or an instantaneous vector extraction algorithm based on digital orthogonal demodulation, the discrete-time sequence is mapped to a complex phasor of the fundamental frequency component, including its real and imaginary parts. The current phase value is calculated using the relationship between the complex phasor amplitude and the real and imaginary parts through an arctangent function. This current phase value corresponds to the current phasor phase angle in the current sampling period and reflects the instantaneous offset of the current relative to the reference.

[0033] During phasor extraction, the phase value is limited to the range of -π to π. When the actual phase change exceeds this range, a foldback phenomenon occurs, leading to a discontinuity in the phase sequence. Phase expansion processing is performed on the original phase sequence of continuous-time sampling points to restore the true continuous change of phase over time. This prevents abrupt changes in the phase sequence due to envelope limitations, eliminates the foldback from -π to π, and achieves a continuous phase sequence. The expanded phase sequence accurately reflects the continuous change of the current phase. The phase expansion processing can eliminate foldback based on the accumulation of phase differences. For example, if the phase of the previous sampling point is π - 0.1, and the phase of the next sampling point becomes -π + 0.1 due to the actual phase increase, after phase expansion, the original phase difference between the two is (-π + 0.1) - (π - 0.1) = -2π + 0.2. Since the actual phase is increasing, the phase difference is corrected to a value that matches the actual phase change trend and is within a reasonable range. The actual phase increase is close to 2π, so the corrected phase difference is taken as a reasonable approximation of 2π. The phase of the previous sampling point is added to the corrected phase difference, i.e., (π - 0.1) + 2π = π + 0.1, and the phase of the next sampling point is corrected to π + 0.1, ensuring the continuity of the phase sequence. The phase difference between adjacent sampling points in the expanded phase sequence is calculated by subtracting the phase of the previous sampling point from the phase of the next sampling point, and the phase differences of all adjacent sampling points are sorted sequentially to form a basic transient phase change sequence. This basic transient phase change sequence reflects the change of the current phase at adjacent sampling times.

[0034] The basic transient phase change sequence is input into a sliding short window for statistical analysis. The sliding short window, with a fixed length, slides sequentially across the sequence, and statistical analysis is performed on the data within the window. The maximum phase jump amplitude is generated based on the maximum phase difference within the sliding short window. This maximum phase jump amplitude refers to the maximum value of the current phase change within a certain window, reflecting whether a drastic abrupt change in the current phase has occurred. Simultaneously, the root mean square (RMS) value of the phase difference within the sliding short window is calculated to generate the short-window phase MMS value. The short-window phase MMS value reflects the dispersion of the phase change within the sliding short window; a large MMS value indicates unstable phase change. Furthermore, by comparing the sign of the phase difference before and after the sampling point corresponding to the maximum amplitude point, the positive or negative direction of the phase shift is determined, generating the phase jump direction. The phase jump direction reflects whether the phase change is positive or negative.

[0035] Phase transient characteristic quantities are constructed based on the maximum amplitude of phase jump, the mean square error of short window phase, and the direction of phase jump. These instantaneous phase changes describe the characteristics of current phase changes from different perspectives, providing an accurate and comprehensive basis for determining whether a short circuit fault has occurred in the feeder, thereby improving the speed and accuracy of short circuit determination at the feeder terminal.

[0036] The first-order amplitude change and the phase transient characteristic are coupled and analyzed to construct a short-circuit characteristic coupling indicator. The short-circuit characteristic coupling indicator is used to characterize the synchronicity of amplitude jump and phase shift caused by impedance drop due to short circuit.

[0037] Specifically, after obtaining the first-order amplitude change and phase transient characteristic of the feeder current, a coupling analysis is performed on the first-order amplitude change and phase transient characteristic to construct a synchronicity index for characterizing the amplitude jump and phase shift caused by the impedance drop due to a short circuit, namely the short-circuit characteristic coupling index. The short-circuit characteristic coupling index indicates that a short circuit event has occurred at the feeder terminal only when the current amplitude jump and phase shift occur synchronously in time and direction. It can effectively distinguish short-circuit disturbances from other loads or harmonic interferences, and achieve rapid and accurate determination of short-circuit events.

[0038] Furthermore, the first-order amplitude change and the phase transient characteristic are coupled and analyzed to construct a short-circuit characteristic coupling indicator, including: normalizing the first-order amplitude change to establish an amplitude jump feature; weighting the phase transient characteristic, mapping the maximum amplitude of the phase jump, the short-window phase mean square error, and the phase jump direction to normalized characteristic components to establish a unified transient characteristic vector; constructing a coupling discriminant function based on the synchronicity of the amplitude jump feature and the transient characteristic vector, matching the instantaneous peak value of the amplitude change with the corresponding time point of the transient characteristic vector, and calculating a coupling score; and outputting the coupling score as a short-circuit characteristic coupling indicator.

[0039] Specifically, the first-order amplitude change is normalized, for example, by using the max-min normalization method. Let the original sequence of the first-order amplitude change be x1, x2, x3…x n The maximum value is x. max The minimum value is x min The normalized sequence is y i =(x i -x min ) / (x max -x min (i=1, 2, 3…n). After normalization to eliminate the influence of dimensions, the amplitude jump characteristics are obtained.

[0040] The phase transient characteristics, including the maximum phase jump amplitude, short-window phase mean square error, and phase jump direction, are weighted and normalized. These characteristics are then mapped to normalized feature components, establishing a unified transient feature vector. The weighting is determined based on the importance of each feature in feeder terminal short-circuit fault identification. For example, through expert experience and statistical analysis, the weights for the maximum phase jump amplitude, short-window phase mean square error, and phase jump direction are determined as w1, w2, and w3, respectively, with the sum of w1, w2, and w3 being 1. Normalization of each feature yields z1, z2, and z3, resulting in a transient feature vector of (w1z1, w2z2, w3z3). By converting the transient eigenvectors into normalized eigencomponents through weighted mapping, the amplitude, direction, and fluctuation intensity can all participate in the coupled analysis at the same scale, thereby improving the accuracy of the analysis results.

[0041] A coupling discriminant function is constructed based on the synchronicity of amplitude jump characteristics and transient characteristic vectors. Synchronicity refers to the temporal consistency between the amplitude jump and phase shift caused by the impedance surge due to a short-circuit fault, i.e., whether the instantaneous peak of the amplitude change matches the time point at which the phase transient characteristic vector undergoes a significant change. The coupling discriminant function is used to quantify the temporal synchronicity and directional consistency between the amplitude jump characteristics and the phase transient characteristic vectors. By identifying the instantaneous peak point in the amplitude jump feature and using its time coordinate as a reference, the corresponding transient feature vector is extracted at the same time point. Correlation coefficients are calculated between the amplitude jump feature and each component of the transient feature vector using a correlation coefficient calculation algorithm, such as the Pearson correlation coefficient formula. This matches the instantaneous peak of the amplitude change with the corresponding time point of the transient feature vector. Different weights are assigned to each component based on their importance in reflecting short-circuit characteristics, and the correlation coefficients are weighted and summed. The weighted summation integrates the matching results of the normalized amplitude of the amplitude jump feature, the maximum amplitude of the phase jump, the short-window phase mean square error, and the phase jump direction. The integrated result is used as a coupling score, which serves as a short-circuit feature coupling indicator. This short-circuit feature coupling indicator characterizes the synchronicity of the amplitude jump and phase shift caused by the impedance drop due to a short circuit. A higher coupling score indicates better synchronicity between the instantaneous peak and the transient feature vector, and a higher probability of a short-circuit fault.

[0042] By comprehensively analyzing and calculating short-circuit characteristic coupling indicators, the synchronicity of amplitude jump and phase shift can be reflected, providing a basis for the accurate identification and diagnosis of short-circuit faults, thereby improving the accuracy and reliability of short-circuit event identification.

[0043] Furthermore, a short-circuit feature coupling indicator is constructed, which previously included: performing a time-series stability evaluation on transient feature vectors within three or more consecutive sampling periods; when the direction of change of the transient feature vector remains consistent at the moment corresponding to the peak amplitude jump, and the time alignment offset of the amplitude change and phase change does not exceed the preset stability range, it is recorded as a stable period, and the coupling discrimination function is allowed to output a coupling score.

[0044] Specifically, the sampling period refers to the time interval for data acquisition. Transient feature vectors are obtained over three or more consecutive sampling periods. Each transient feature vector includes the phase jump direction, phase jump amplitude, and short-window phase mean square error corresponding to the peak amplitude rise. Temporal stability is evaluated on the transient feature vectors over three or more consecutive sampling periods. This evaluation includes the direction of change of the instantaneous feature vector at the moment corresponding to the peak amplitude rise, as well as the time alignment offset of amplitude and phase changes. The peak amplitude rise refers to the maximum value in the amplitude rise feature obtained after normalization of the first-order amplitude change, reflecting the severity of amplitude changes caused by short-circuit faults. The phase jump direction corresponding to the peak amplitude rise in consecutive sampling periods is compared. If the direction remains consistent across three or more periods (e.g., showing an increasing or decreasing trend), it indicates good consistency in the phase transient feature at that moment.

[0045] Time alignment offset refers to the difference between the moments when amplitude surge characteristics and phase transient characteristics undergo significant changes on the time axis. Since short-circuit faults cause impedance drops, leading to amplitude surges and phase shifts, a preset stability range is set. If the time alignment offset of amplitude and phase changes does not exceed this preset stability range (e.g., within milliseconds), it indicates that the two exhibit good temporal synchronization.

[0046] When the transient feature vector maintains the same direction of change at the moment corresponding to the peak amplitude jump, and the time alignment offset of the amplitude change and phase change does not exceed the preset stability range, it is recorded as a stable period. Only when it is in a stable period is the coupling discrimination function allowed to output a coupling score to avoid incorrect fault judgment due to data instability or abnormal fluctuations.

[0047] By evaluating the timing stability, coupling scoring is ensured to be triggered only when real short-circuit disturbances exist and have consistent characteristics, thereby improving the accuracy and reliability of short-circuit characteristic coupling indicators. This enables rapid determination of feeder short-circuit events while improving the accuracy and reliability of short-circuit identification.

[0048] Furthermore, if the direction of change of the amplitude jump peak and the time alignment offset of the amplitude change and phase change do not meet the requirements, it is recorded as an unstable period and will not enter the short circuit event triggering process.

[0049] Specifically, a temporal stability evaluation is performed on transient feature vectors within three or more consecutive sampling periods. The consistency between the direction of amplitude change and the direction of phase change in each amplitude rise peak and its corresponding phase transient feature vector within the consecutive sampling periods is determined, as well as the time offset between the amplitude peak and the phase transient peak. If any of the indicators does not meet the requirements, i.e., the direction of change of the amplitude rise peak is inconsistent with the direction of amplitude change and phase change, or the time alignment offset between the amplitude peak and the phase peak exceeds the preset stability range, then the current sampling period is determined to be an unstable period, and the short-circuit event triggering process is not initiated.

[0050] By filtering and judging, unstable cycles are eliminated, reducing false alarms or missed short circuit events. This ensures that only stable data that truly reflects the characteristics of short circuit faults is used for coupled scoring analysis, improving the accuracy and reliability of short circuit fault identification and achieving high-precision, low-false-alarm, fast and reliable short circuit detection.

[0051] When the short-circuit characteristic coupling indicator exceeds the preset coupling threshold, an abnormal reporting command for the short-circuit event is triggered. Based on the triggering time and the duration of the phase transient characteristic quantity, the rapid alarm level of the short-circuit event is determined, and alarm information is issued to the main station.

[0052] Specifically, after obtaining the short-circuit characteristic coupling indicators, the short-circuit characteristic coupling index is compared with a preset coupling threshold. When the short-circuit characteristic coupling index is greater than or equal to the preset coupling threshold, it indicates that the synchronization of the current amplitude jump and phase transient characteristics has reached the short-circuit event judgment condition, triggering an abnormal reporting command for the short-circuit event. The preset coupling threshold is determined based on historical data. A large amount of historical data is collected, including electrical quantity data under normal operating conditions and short-circuit fault conditions, including current amplitude and phase information. Multiple historical data are analyzed to extract key features such as first-order amplitude change and phase transient characteristics, and the corresponding short-circuit characteristic coupling indicators are calculated. Statistical analysis methods, such as normal distribution analysis and average value calculation, are used to determine the distribution range and typical value of the short-circuit characteristic coupling indicators under normal operating conditions. The mean of the short-circuit characteristic coupling indicators under normal operating conditions plus ±2 standard deviations is selected as the preset coupling threshold. Simultaneously, adaptive correction is performed based on the current magnitude and impedance characteristics of different feeders to adapt to different operating conditions. The coupling threshold represents the critical score for the synchronization of amplitude jump and phase transient characteristics reaching the short-circuit judgment standard.

[0053] Simultaneously with triggering the abnormal reporting command for a short-circuit event, the rapid alarm level of the short-circuit event is determined by combining the trigger time and the duration of the phase transient characteristic quantity within a continuous sampling period. The trigger time refers to the specific point in time when the short-circuit characteristic coupling indicator exceeds a preset coupling threshold, reflecting the start time of the short-circuit fault. The duration reflects the duration of the phase transient after the short-circuit fault occurs. Different duration intervals and alarm levels are pre-defined. By monitoring the duration of the phase transient characteristic quantity in real time and matching it with the preset intervals, the corresponding rapid alarm level is determined. The alarm level includes multiple levels, such as minor, moderate, and severe, to indicate the urgency of the short-circuit event. The longer the trigger time and the duration of the phase transient characteristic quantity, the higher the alarm level. After determining the rapid alarm level of the short-circuit event, the alarm information containing the trigger time, short-circuit characteristic coupling indicator, and alarm level is released to the main station to support remote monitoring and rapid dispatch of the distribution network, improving the real-time performance and security of the distribution network's short-circuit response.

[0054] By judging the coupled indicators of short-circuit characteristics, rapid detection and graded alarm of short-circuit events in feeder terminals can be achieved. At the same time, the reliability and accuracy of alarms are improved by jointly judging the threshold and duration. The system can classify and process short-circuit events according to their severity, enabling maintenance personnel to take corresponding measures according to different alarm levels, thereby improving the pertinence and efficiency of fault handling and effectively improving the real-time performance and security of short-circuit response in the distribution network.

[0055] Furthermore, based on the trigger time and the duration of the phase transient characteristic, the rapid alarm level of the short-circuit event is determined, and alarm information is issued to the main station. This includes: simultaneously extracting instantaneous sampling data and half-cycle synchronous sampling data within the same period based on the trigger time, calculating the corresponding phase difference and amplitude change amount respectively, and forming a verification sampling pair; constructing a delay consistency index using the verification sampling pair, and comparing the differences between instantaneous sampling and synchronous sampling in terms of phase change direction, phase jump amplitude, and amplitude rise degree through time alignment; calculating a micro-delay consistency index based on the phase change direction, establishing a difference index based on the phase jump amplitude, and calculating a response consistency index based on the amplitude rise degree; and managing the validity of the short-circuit event based on the micro-delay consistency index, difference index, and response consistency index.

[0056] Specifically, when the short-circuit characteristic coupling indicator exceeds a preset coupling threshold, triggering a short-circuit event abnormal reporting command and determining the trigger time, instantaneous sampling data and half-cycle synchronous sampling data within the same sampling cycle are simultaneously extracted based on the trigger time. The corresponding phase difference and amplitude mutation are calculated to form corresponding verification sampling pairs. Half-cycle synchronous sampling data refers to sampling at intervals of half a power frequency cycle to obtain the overall change characteristics of the current within half a cycle. The phase difference and amplitude mutation corresponding to the instantaneous sampling data and half-cycle synchronous sampling data within the same cycle are calculated separately. The phase difference refers to the difference in phase between the phasor of the instantaneous sampling data and the synchronous sampling phasor of the half-cycle synchronous sampling data within the same cycle, reflecting the phase relationship between the currents. The amplitude mutation is obtained by differentially calculating the sampling current amplitude in the instantaneous sampling data and the amplitude of the half-cycle synchronous sampling data at the same time point.

[0057] A latency consistency index is constructed using validation sampling pairs. A timestamp-based matching algorithm is used to time-align the differences between instantaneous and synchronously sampled data in terms of phase change direction, phase jump amplitude, and amplitude rise degree. Differences are compared, and a micro-latency consistency index is calculated based on the deviation of the phase change direction between instantaneous and synchronous samples, reflecting the degree of consistency between them in the phase change direction. A difference index is established based on the phase jump amplitude, reflecting the degree of deviation between instantaneous and synchronous samples in phase amplitude; the smaller the difference, the more accurate the phase jump amplitude. An amplitude response consistency index is calculated based on the amplitude rise degree, reflecting the response of instantaneous and synchronous samples to amplitude rises. If the responses are consistent, the extraction of amplitude rise features is accurate and reliable.

[0058] Then, based on the calculated micro-delay consistency index, difference index, and response consistency index, the validity of short-circuit events is determined and managed. When all three types of indicators meet the set conditions, the short-circuit event is determined to be valid. Combined with the trigger time and the duration of the phase transient characteristic quantity, the rapid alarm level of the short-circuit event is determined and an alarm message is issued to the main station.

[0059] By forming verification sampling pairs and performing multi-index verification, the validity of short-circuit events is judged, improving the accuracy and effectiveness of short-circuit event judgment in feeder terminals and reducing false positives and false negatives. For short-circuit events determined to be valid, the rapid alarm level is determined by combining the trigger time and the duration of phase transient characteristics, thereby improving the authenticity and reliability of alarm information.

[0060] Furthermore, the validity determination management of short-circuit events is based on the micro-latency consistency index, difference index, and response consistency index, including: when the micro-latency consistency index is within a preset directional consistency range, the difference index is lower than a set amplitude deviation threshold, and the response consistency index exceeds the response consistency lower limit threshold, the short-circuit event is determined to be valid; after determining the rapid alarm level of the short-circuit event, an alarm message is issued to the main station.

[0061] Furthermore, if any one of the micro-latency consistency index, difference index, or response consistency index fails the test, the short-circuit event is deemed invalid. A suspicious short-circuit event identifier is configured based on the degree of suspicion of the index, and the suspicious short-circuit event identifier is used to trigger a secondary sampling verification within a short time window.

[0062] Specifically, the validity management of short-circuit events is achieved using micro-delay consistency indicators, difference indicators, and response consistency indicators. The micro-delay consistency indicator is compared with a preset directional consistency range to determine the synchronicity of amplitude jumps and phase transitions in time and direction. Simultaneously, the amplitude difference indicator is compared with a set amplitude deviation threshold to assess the deviation of the transient amplitude peak between instantaneous sampling and half-cycle synchronous sampling. The response consistency indicator is also compared with a lower limit threshold for response consistency. When the micro-delay consistency indicator is within the preset directional consistency range, the difference indicator is below the set amplitude deviation threshold, and the response consistency indicator exceeds the lower limit threshold for response consistency—that is, when all three indicators meet the preset conditions—the short-circuit event is determined as a valid event. The duration of the phase transient characteristic is then combined to determine the rapid alarm level, and an alarm message is issued to the main station. The preset conditions for each indicator can be calculated based on historical data, including the mean and standard deviation, with the mean multiplied by a factor such as 2 times the standard deviation. Alternatively, they can be set based on expert experience.

[0063] If any one of the micro-latency consistency index, difference index, or response consistency index fails the judgment, the short-circuit event is determined to be an invalid event, and a suspicious short-circuit event identifier is generated based on the degree of deviation of each index from the preset conditions. The degree of deviation of each index from the threshold is calculated, and each index is assigned a weight to form a comprehensive suspicion score. Based on the comprehensive suspicion score, a suspicious short-circuit event identifier is generated within a predefined grade range to indicate the suspicion level of the event, such as low level and high level. A secondary sampling verification is triggered in a short time window based on the suspicious short-circuit event identifier. During the secondary sampling verification process, instantaneous sampling data and half-cycle synchronous sampling data are collected again, and the corresponding phase difference and amplitude mutation amount are calculated to form a verification sampling pair. The micro-latency consistency index, difference index, and response consistency index are recalculated to further determine whether the event is a real short-circuit event. If the secondary sampling verification result meets the valid judgment conditions, the previous invalid judgment is corrected, and the subsequent rapid alarm level judgment is performed according to the processing procedure for valid short-circuit events, and alarm information is issued to the main station. If the valid judgment conditions are still not met, the event is confirmed as an invalid event, effectively suppressing false alarms and false triggers.

[0064] By employing index verification and secondary sampling mechanisms, high-reliability short-circuit event determination is achieved, ensuring that alarm information is reported only when a genuine short-circuit event exists, reducing false positives and incorrect judgments, and effectively improving the accuracy and reliability of short-circuit detection in feeder terminals.

[0065] Furthermore, after issuing alarm information to the main station, the process also includes: establishing an early warning verification window based on the alarm information; verifying the alarm processing of short circuit events in the early warning verification window, and performing verification management.

[0066] Specifically, after issuing a short-circuit event alarm to the main station, an early warning verification window is established based on the issued alarm information. This early warning verification window is a specific time interval, with the alarm trigger time as the starting point. The length of the early warning verification window is set according to the duration of the short-circuit characteristics and the sampling period, for example, several to dozens of sampling periods, to ensure coverage of the complete transient process of the short-circuit event. Within the early warning verification window, instantaneous sampling data of the feeder is continuously collected, and the amplitude constraints, first-order amplitude changes, and phase transient characteristics are monitored and compared in real time to verify the alarm processing of the short-circuit event and to perform verification management. Verification management includes: comparing the continuous sampling points collected within the early warning verification window with the characteristics at the time of alarm triggering; calculating the duration, direction consistency, and amplitude deviation of amplitude and phase characteristics; determining whether the short-circuit event characteristics remain stable; and for unstable or deviating short-circuit events, triggering secondary sampling verification to correct or cancel the previously issued alarm, and taking corresponding corrective and processing measures.

[0067] By establishing an early warning verification window to verify alarm processing, real-time confirmation and correction of issued short-circuit alarms can be achieved, ensuring that only continuous events that meet the characteristics of short circuits are recognized by the main station. This improves the reliability, accuracy, and anti-false alarm capability of rapid short-circuit alarms, and reduces unnecessary resource waste and operational risks caused by false alarms.

[0068] In summary, the short-circuit current rapid identification and alarm method for feeder terminals provided in this application has the following technical effects:

[0069] 1. By acquiring current data in real time and quickly calculating the first-order amplitude change and phase transient characteristics, the sudden change characteristics of the current can be captured in a short time. Combined with coupling analysis and stability evaluation, it can quickly determine whether a short circuit event has occurred in the feeder, thereby improving the fault response speed.

[0070] 2. Feature information is extracted from both amplitude and phase dimensions and coupled analysis is performed. This comprehensively considers the synchronicity of amplitude jump and phase shift caused by impedance surge due to short circuit, avoiding the limitations of single-feature discrimination. Simultaneously, through timing stability evaluation and validity determination management, interference factors and misjudgments are further eliminated, improving the accuracy and reliability of feeder short-circuit event determination.

[0071] 3. The rapid alarm level of a short circuit event is determined based on the trigger time and the duration of the phase transient characteristic quantity. This allows for graded processing according to the severity of the short circuit event, enabling maintenance personnel to take corresponding measures based on different alarm levels, thereby improving the pertinence and efficiency of fault handling.

[0072] 4. By establishing an early warning verification window to verify and manage alarm processing, the accuracy and reliability of alarm information are ensured, avoiding false alarms and missed alarms, and improving the overall stability and reliability of feeder terminal operation.

[0073] Example 2, based on the same inventive concept as the short-circuit current rapid identification and alarm method for feeder terminals in the foregoing examples, such as... Figure 2 As shown, this application provides a fast short-circuit current detection and alarm system for feeder terminals, wherein the fast short-circuit current detection and alarm system for feeder terminals includes:

[0074] The data calculation module 11 is used to acquire instantaneous sampling data of the feeder current in real time, calculate the rate of change of current amplitude based on adjacent sampling points of the instantaneous sampling data, and obtain a first-order amplitude change quantity used to characterize the degree of current abrupt change; the feature quantity construction module 12 is used to extract phasors from the instantaneous sampling data within the same sampling period, calculate the current phase value, and construct a phase transient feature quantity using the phase difference of continuous time sampling points. The phase transient feature quantity includes the maximum amplitude of phase jump, the short-window phase mean square error, and the phase jump direction; the coupling analysis module 13 is used to perform coupling analysis on the first-order amplitude change quantity and the phase transient feature quantity to construct a short-circuit characteristic coupling indicator. The short-circuit characteristic coupling indicator is used to characterize the synchronicity of amplitude jump and phase shift caused by impedance drop due to short circuit; the abnormal alarm module 14 is used to trigger an abnormal reporting command for short-circuit events when the short-circuit characteristic coupling indicator exceeds a preset coupling threshold, determine the rapid alarm level of the short-circuit event based on the trigger time and the duration of the phase transient feature quantity, and issue alarm information to the main station.

[0075] Furthermore, the feature quantity construction module 12 is also used to: perform phase expansion processing on the original phase sequence of continuous time sampling points to eliminate the back-and-forth from -π to π, making the phase sequence continuous; calculate the phase difference between adjacent sampling points of the expanded phase sequence to form a basic transient phase change sequence; perform sliding short-window statistical analysis on the basic transient phase change sequence, generate the maximum amplitude of the phase jump based on the maximum phase difference within the sliding short window, generate the root mean square error of the short-window phase based on the root mean square value of the phase difference within the sliding short window, and determine the phase jump direction based on the sign of the phase difference before and after the maximum amplitude point; and construct phase transient feature quantities based on the maximum amplitude of the phase jump, the root mean square error of the short-window phase, and the phase jump direction.

[0076] Furthermore, the coupling analysis module 13 is also used to: normalize the first-order amplitude change to establish amplitude jump characteristics; weight the phase transient characteristics, mapping the maximum amplitude of the phase jump, the short-window phase mean square error, and the phase jump direction to normalized characteristic components to establish a unified transient characteristic vector; construct a coupling discrimination function based on the synchronicity of the amplitude jump characteristics and the transient characteristic vector, matching the instantaneous peak value of the amplitude change with the corresponding time point of the transient characteristic vector to calculate the coupling score; and output the coupling score as a short-circuit characteristic coupling indicator.

[0077] Furthermore, the coupling analysis module 13 is also used to: perform time-series stability evaluation on transient feature vectors within three or more consecutive sampling periods; when the direction of change of the transient feature vector remains consistent at the moment corresponding to the peak amplitude jump, and the time alignment offset of amplitude change and phase change does not exceed the preset stability range, it is recorded as a stable period, and the coupling discrimination function is allowed to output a coupling score.

[0078] Furthermore, the coupling analysis module 13 is also used to: if the change direction of the amplitude jump peak and the time alignment offset of the amplitude change and phase change do not meet the requirements, it is recorded as an unstable period and will not enter the short circuit event triggering process.

[0079] Furthermore, the anomaly alarm module 14 is also used to: simultaneously extract instantaneous sampling data and half-cycle synchronous sampling data within the same period according to the trigger time, calculate the corresponding phase difference and amplitude change amount respectively, and form a verification sampling pair; construct a time delay consistency index using the verification sampling pair, and compare the differences between instantaneous sampling and synchronous sampling in phase change direction, phase jump amplitude and amplitude rise degree by time alignment; calculate the micro-time delay consistency index according to the phase change direction, establish a difference index according to the phase jump amplitude, and calculate the response consistency index according to the amplitude rise degree; and perform validity judgment management of short-circuit events based on the micro-time delay consistency index, difference index and response consistency index.

[0080] Furthermore, the abnormal alarm module 14 is also used to: determine that the short circuit event is valid when the micro-latency consistency index is within the preset directional consistency range, the difference index is lower than the set amplitude deviation threshold, and the response consistency index exceeds the response consistency lower limit threshold; and after determining the fast alarm level of the short circuit event, issue alarm information to the main station.

[0081] Furthermore, the anomaly alarm module 14 is also used to: determine that the short circuit event is invalid when any one of the micro-latency consistency index, difference index, and response consistency index fails the test; configure a suspicious short circuit event identifier according to the degree of suspicion of the index; and trigger a secondary sampling verification for a short time window using the suspicious short circuit event identifier.

[0082] Furthermore, the abnormal alarm module 14 is also used to: establish an early warning verification window based on the alarm information; perform alarm processing verification of short circuit events in the early warning verification window, and perform verification management.

[0083] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The method and specific examples for rapid short-circuit current identification and alarm for feeder terminals in the foregoing embodiment 1 are also applicable to the rapid short-circuit current identification and alarm system for feeder terminals in this embodiment. Through the foregoing detailed description of the rapid short-circuit current identification and alarm method for feeder terminals, those skilled in the art can clearly understand the rapid short-circuit current identification and alarm system for feeder terminals in this embodiment. Therefore, for the sake of brevity, it will not be described in detail here.

[0084] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0085] Obviously, those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of this application.

Claims

1. A method for rapid short-circuit current detection and alarm for feeder terminals, characterized in that, The method includes: Real-time acquisition of instantaneous sampling data of feeder current; calculation of current amplitude change rate based on adjacent sampling points of the instantaneous sampling data; obtaining a first-order amplitude change quantity used to characterize the degree of current abrupt change. Within the same sampling period, phasor extraction is performed on the instantaneous sampled data to calculate the current phase value. The phase transient characteristic is constructed using the phase difference of continuous time sampling points. The phase transient characteristic includes the maximum amplitude of phase jump, the short window phase mean square error, and the phase jump direction. The first-order amplitude change and the phase transient characteristic are coupled and analyzed to construct a short-circuit characteristic coupling indicator. The short-circuit characteristic coupling indicator is used to characterize the synchronicity of amplitude jump and phase shift caused by impedance drop due to short circuit. When the short-circuit characteristic coupling indicator exceeds the preset coupling threshold, an abnormal reporting command for the short-circuit event is triggered. Based on the triggering time and the duration of the phase transient characteristic quantity, the rapid alarm level of the short-circuit event is determined, and alarm information is issued to the main station. Phase transient characteristics are constructed using the phase difference between consecutive time sampling points, including: The original phase sequence of continuous time sampling points is subjected to phase expansion processing to eliminate the reflection from -π to π, so that the phase sequence is continuous; Calculate the phase difference between adjacent sampling points of the expanded phase sequence to form the basic transient phase change sequence; The basic transient phase change sequence is subjected to sliding window statistical analysis. The maximum amplitude of the phase jump is generated based on the maximum phase difference within the sliding window, and the root mean square error of the phase difference within the sliding window is generated based on the root mean square value of the phase difference. The direction of the phase jump is determined based on the sign of the phase difference before and after the maximum amplitude point. Phase transient characteristic quantities are constructed based on the maximum amplitude of the phase jump, the mean square error of the short window phase, and the direction of the phase jump. The first-order amplitude change and the phase transient characteristic are coupled and analyzed to construct short-circuit characteristic coupling indicators, including: The first-order amplitude change is normalized to establish amplitude jump characteristics; The phase transient features are weighted and calibrated, and the maximum amplitude of the phase jump, the root mean square error of the short window phase, and the direction of the phase jump are mapped to normalized feature components to establish a unified transient feature vector. Based on the synchronicity of the amplitude jump feature and transient feature vector, a coupling discrimination function is constructed, and the instantaneous peak value of the amplitude change is matched with the corresponding time point of the transient feature vector to calculate the coupling score. The coupling score is output as a short-circuit feature coupling indicator.

2. The method for rapid short-circuit current determination and alarm for feeder terminals as described in claim 1, characterized in that, Constructing short-circuit feature coupling indicators, previously including: Perform temporal stability evaluation on transient feature vectors within three or more consecutive sampling periods; When the transient eigenvector maintains the same direction of change at the moment corresponding to the peak amplitude jump, and the time alignment offset of the amplitude change and phase change does not exceed the preset stability range, it is recorded as a stable period, and the coupling discrimination function is allowed to output a coupling score.

3. The method for rapid short-circuit current identification and alarm for feeder terminals as described in claim 2, characterized in that, If the direction of change of the amplitude jump peak and the time alignment offset of the amplitude change and phase change do not meet the requirements, it is recorded as an unstable period and will not enter the short circuit event triggering process.

4. The method for rapid short-circuit current identification and alarm for feeder terminals as described in claim 1, characterized in that, Based on the triggering time and the duration of the phase transient characteristic, a rapid alarm level for the short-circuit event is determined, and an alarm message is sent to the main station, including: Based on the trigger time, instantaneous sampling data and half-cycle synchronous sampling data within the same period are extracted simultaneously, and the corresponding phase difference and amplitude change amount are calculated respectively to form a verification sampling pair. The aforementioned verification sampling is used to construct a time delay consistency index, and the differences between instantaneous sampling and synchronous sampling in terms of phase change direction, phase jump amplitude, and amplitude jump degree are compared in time alignment. The micro-delay consistency index is calculated based on the direction of phase change, the difference index is established based on the phase jump amplitude, and the response consistency index is calculated based on the magnitude of the amplitude jump. The validity of short-circuit events is determined and managed based on the aforementioned micro-latency consistency index, difference index, and response consistency index.

5. The method for rapid short-circuit current determination and alarm for feeder terminals as described in claim 4, characterized in that, The validity management of short-circuit events is based on the aforementioned micro-latency consistency index, difference index, and response consistency index, including: When the micro-delay consistency index is within the preset directional consistency range, the difference index is lower than the set amplitude deviation threshold, and the response consistency index exceeds the response consistency lower limit threshold, the short circuit event is determined to be valid. After determining the rapid alarm level of the short circuit event, an alarm message is sent to the main station.

6. The method for rapid short-circuit current determination and alarm for feeder terminals as described in claim 5, characterized in that, If any one of the micro-latency consistency index, difference index, or response consistency index fails, the short-circuit event is deemed invalid. A suspicious short-circuit event identifier is configured based on the degree of suspicion of the index, and the suspicious short-circuit event identifier is used to trigger a secondary sampling verification within a short time window.

7. The method for rapid short-circuit current determination and alarm for feeder terminals as described in claim 1, characterized in that, After sending an alert to the main site, it also includes: Establish an early warning verification window based on the alarm information; The alarm processing verification for short circuit events is performed in the warning verification window, and verification management is executed.

8. A short-circuit current rapid identification and alarm system for feeder terminals, characterized in that, The steps for implementing the short-circuit current rapid discrimination alarm method for feeder terminals according to any one of claims 1 to 7 include: The data calculation module is used to acquire instantaneous sampling data of the feeder current in real time, calculate the rate of change of current amplitude based on adjacent sampling points of the instantaneous sampling data, and obtain the first-order amplitude change quantity used to characterize the degree of current abrupt change. The feature construction module is used to extract phasors from the instantaneous sampled data within the same sampling period, calculate the current phase value, and construct phase transient feature quantities using the phase difference of continuous time sampling points. The phase transient feature quantities include the maximum phase jump amplitude, the short window phase mean square error, and the phase jump direction. The coupling analysis module is used to perform coupling analysis on the first-order amplitude change and the phase transient characteristic to construct a short-circuit characteristic coupling indicator. The short-circuit characteristic coupling indicator is used to characterize the synchronicity of the amplitude jump and phase shift caused by the impedance drop caused by the short circuit. The abnormal alarm module is used to trigger an abnormal reporting command for a short circuit event when the short circuit characteristic coupling indicator exceeds a preset coupling threshold. Based on the triggering time and the duration of the phase transient characteristic quantity, the module determines the rapid alarm level of the short circuit event and issues alarm information to the main station.

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