Primary and secondary fusion complete ring main unit fault diagnosis method and system and ring main unit

Abstract

The invention relates to the technical field of power system power distribution equipment detection, in particular to a primary and secondary fusion complete ring main unit fault diagnosis method and system, a ring main unit and a computer readable storage medium. According to the method, a transient exclusion time window is established by using operation anchor point signals of a primary fusion terminal and a secondary fusion terminal, and a thermal inertia model containing a thermal time constant is introduced to perform unified characterization and theoretical trajectory deduction on load resistance heating and discharge heating; the candidate discharge events can obtain verifiable verification through temperature rise trend consistency and the reference deviation degree under the working conditions of operation disturbance and thermal response lag; therefore, the judgment consistency of non-operation related insulation discharge faults and contact degradation overheating faults is improved, false alarm and missing alarm are reduced, and the online diagnosis stability and conclusion credibility of the complete ring main unit under complex electromagnetic environment and dynamic load conditions are enhanced.

Description

Technical Field

[0001] This invention relates to the field of power system distribution equipment testing technology, specifically to a method, system, ring network box, and computer-readable storage medium for fault diagnosis of integrated primary and secondary ring network boxes. Background Technology

[0002] With the advancement of intelligent distribution networks and condition-based maintenance, integrated ring main units (RMS) are key node equipment in distribution networks. They typically integrate primary switching units with secondary measurement, control, protection, and communication terminals into a single unit to achieve online sensing, alarming, and maintenance support of operational status. To reduce the risk of power outages caused by sudden faults, online monitoring and fault diagnosis of critical electrical connections within the RMS have become a common requirement.

[0003] In existing technologies, monitoring methods for early-stage potential hazards in ring main units typically include partial discharge detection and temperature rise monitoring. Partial discharge detection uses methods such as ultra-high frequency, ultrasound, or electrical transients to acquire discharge-related signals, reflecting early signs of insulation degradation. Temperature rise monitoring often uses temperature sensors at joints, busbars, or cable connections to obtain temperature information, indicating risks such as increased contact resistance and current-carrying heating. Some solutions further superimpose load current and environmental parameters, using thresholds or rules for alarm and grading judgments.

[0004] However, in the actual operation of integrated ring main units, the opening and closing operations of circuit breakers, load switches, or grounding switches are accompanied by sudden changes in coil current, contact bounce, and transient electromagnetic pulses, which can easily introduce pulse-type interference into the partial discharge monitoring channel. This type of interference may be similar to partial discharge signals in the time or frequency domain. Existing solutions that rely solely on fixed thresholds, simple filtering, or coarse-grained timestamp alignment often cannot reliably distinguish between "operation-induced interference" and "real insulation defect discharge," thus generating frequent false alarms and increasing ineffective inspections.

[0005] Meanwhile, existing temperature rise monitoring systems mostly use fixed temperature thresholds or fixed temperature rise thresholds for judgment, failing to fully consider the resistance heating effect caused by load current fluctuations and the impact of ambient temperature changes on the base temperature rise. Under low load conditions, weak temperature rises caused by contact degradation may be masked and lead to missed alarms; under high load or high ambient temperature conditions, normal current-carrying heating may trigger false alarms, resulting in a decrease in alarm reliability.

[0006] Furthermore, ring main units are mostly deployed in outdoor or semi-outdoor environments, where condensation and contamination are common due to temperature and humidity variations. Condensation-related surface discharges and intermittent insulation defects often exhibit characteristics such as intermittent occurrence, large amplitude fluctuations, and persistent instability, making it difficult to characterize a single event. In situations where there may be inconsistencies or asynchrony between partial discharge signals and temperature rise changes, existing fault diagnosis conclusions are prone to instability or contradictions, leading to difficulties in accurately identifying fault types and insufficient alarm reliability.

[0007] Therefore, there is an urgent need in this field for a fault diagnosis solution for integrated primary and secondary ring main units, which can reliably identify candidate discharge events and achieve stable output of fault conclusions under complex operating conditions such as transient interference from switch operation, load and environmental disturbances, and condensation / intermittent defects, so as to improve the effectiveness and usability of online diagnosis. Summary of the Invention

[0008] (I) The technical problem to be solved by the present invention is that when existing integrated primary and secondary ring network boxes are monitored online, they usually rely on fixed thresholds of partial discharge or joint temperature for independent alarms. However, when transient pulse interference is generated by switch opening and closing or grounding operations, and when changes in load and environmental conditions cause partial discharge signals and temperature rise responses to lag or become asynchronous, the existing technology has difficulty in reliably distinguishing between operation-related interference and non-operation-related discharge, and it is difficult to take into account the judgment of discharge hazards and contact deterioration heat generation. This results in low diagnostic accuracy and frequent false alarms and missed alarms.

[0009] (II) Technical Solution To address the aforementioned technical problems, this invention provides a fault diagnosis method for a primary and secondary integrated ring network enclosure, comprising the following steps: S1. Collect partial discharge pulse signals, joint temperature signals, ambient temperature signals, and load current signals of the target electrical connection parts; and obtain the operation anchor point signals representing the time of grounding operation or opening and closing operation from the primary and secondary fusion terminal. S2. Monitor the partial discharge pulse signal, and when a candidate discharge event that meets the preset triggering conditions is identified, lock the triggering time of the candidate discharge event; S3. Based on the operation anchor signal, construct an operation rejection time window defined by a preset duration before operation and a preset duration after operation; determine whether the triggering time falls within the operation rejection time window: if it falls within, determine the candidate discharge event as an operation interference event and record the characteristics of the candidate discharge event; if it does not fall within, determine the candidate discharge event as an event to be verified. S4. Construct a thermal inertia lag time window based on the triggering time; within the thermal inertia lag time window, generate an actual temperature rise trajectory based on the joint temperature signal and the ambient temperature signal; and deduce the theoretical temperature rise trajectory based on the resistance heating effect of the load current signal and the discharge heating effect of the event to be verified, combined with the preset thermal inertia model. S5. Calculate the trend consistency index between the actual temperature rise trajectory and the theoretical temperature rise trajectory, and calculate the deviation of the actual temperature rise trajectory from the reference temperature rise trajectory derived solely from the load current signal; perform a graded judgment based on the trend consistency index and the deviation: when the trend consistency index meets the preset matching condition and the event to be verified persists within the thermal inertia hysteresis time window, output a non-operation-related real partial discharge fault conclusion; when the trend consistency index does not meet the preset matching condition and the deviation exceeds the preset overheating threshold, output a contact degradation overheating fault conclusion; otherwise, output an observation anomaly event conclusion.

[0010] The fault diagnosis method provided by this invention uses partial discharge pulse signals, joint temperature signals, ambient temperature signals, and load current signals from key electrical connections of a ring main unit as multi-source physical observations. It also utilizes grounding or switching operation anchor point signals provided by a primary and secondary fusion terminal to establish event timing references. First, during continuous monitoring of partial discharge pulse signals, when a candidate discharge event meets preset triggering conditions, its triggering time is locked. An operation exclusion time window is constructed based on the time relationship between this triggering time and the operation anchor point signal. This achieves priority identification and feature retention of pulse events during the transient phase of switch operation, naturally coupling the diagnostic process with the actual operation of the equipment in terms of timing. For candidate events that do not fall into the exclusion time window, they are treated as events to be verified and introduced into a thermal inertia hysteresis time window. Within this lag time window, the actual temperature rise trajectory and the theoretical temperature rise trajectory, which is superimposed on the load resistance thermal effect and the discharge thermal effect and constrained by a preset thermal inertia model, are formed respectively. This incorporates the lag relationship between transient discharge and temperature rise response into the same verification framework. Furthermore, by calculating the trend consistency index between the actual temperature rise trajectory and the theoretical temperature rise trajectory, and combining it with the deviation of the actual temperature rise from the pure load reference temperature rise trajectory, a graded judgment is made. This allows candidate events to converge to the conclusions of non-operation-related real partial discharge faults, contact degradation overheating faults, or observed abnormal events under verifiable physical consistency conditions such as "consistent trend and continuous discharge" and "inconsistent trend and deviation exceeding the threshold". This results in a more stable, interpretable, and verifiable online diagnostic output under dynamic load and complex electromagnetic conditions.

[0011] Furthermore, the operation anchor signal includes at least one of the following signals: the abrupt change time of the opening and closing coil current waveform of the circuit breaker or load switch; the change time of the auxiliary contact of the grounding switch or disconnecting switch; the jump time of the switch position indication signal; and the operation command timestamp output by the relay protection device or the primary and secondary fusion terminal.

[0012] By setting the operation anchor signal as at least one of the following: the moment of sudden change in the current waveform of the opening and closing coil, the moment of change in the auxiliary contact, the moment of jump in the switch position indication signal, or the timestamp of the operation command, this invention enables the timing of the switch operation to be directly determined by the existing observable signals on the secondary side of the ring main unit. This provides a clear and quantifiable timing reference for constructing the operation exclusion time window, reduces the impact of timing deviations caused by manual calibration or coarse-grained timestamps on interference discrimination, and improves the stability and consistency of operation-related transient interference identification. Furthermore, when two or more of these signals are used as anchor sources simultaneously, mutual verification and validity judgment of the anchors can be further achieved, thereby enhancing the timing reliability under signal loss, delay, or jitter conditions.

[0013] Furthermore, to determine the candidate discharge event as an operational interference event, the following waveform characteristic conditions must be met simultaneously: the duration of the pulse cluster of the candidate discharge event is less than a preset pulse width threshold; and the proportion of the preset high-frequency band energy obtained by frequency domain analysis of the pulse signal of the candidate discharge event to the total energy is lower than a preset spectral energy proportion threshold; if the candidate discharge event falls within the operational rejection time window but does not simultaneously meet the above waveform characteristic conditions, it is determined as an event to be verified.

[0014] By introducing a dual constraint of "pulse cluster duration threshold" and "preset high-frequency band energy proportion threshold" on the basis of time window discrimination, this invention elevates the judgment of operation-related interference from simple time-series correlation to a joint discrimination that combines time-domain morphology and spectral distribution characteristics. This ensures that candidate discharge events classified as operation interference events simultaneously meet the waveform characteristics of "transient" and "low high-frequency energy proportion", thereby reducing the probability of falsely rejecting real partial discharges when they occur close to the operation time. At the same time, for events that fall within the operation rejection time window but do not meet the above waveform characteristic conditions, they are transferred to the verification path, avoiding premature rejection of potential real defect events under the background of operation disturbance. This allows subsequent thermal inertial verification to still verify their physical consistency, thereby improving the stability and credibility of the diagnostic conclusions.

[0015] Furthermore, the method also includes the steps of constructing an operation interference fingerprint database and fallback identification: establishing an operation interference fingerprint database, and storing the waveform feature parameters of events identified as operation interference events as fingerprint samples in the operation interference fingerprint database, wherein the waveform feature parameters include at least the duration of the pulse cluster and the proportion of the energy of the preset high-frequency band to the total energy; in subsequent monitoring, when the operation anchor signal is not obtained or the operation anchor signal does not meet the preset validity criteria, the waveform feature parameters of newly identified candidate discharge events are matched with the fingerprint samples in the operation interference fingerprint database; if the matching similarity exceeds a preset similarity threshold, the candidate discharge event is identified as an operation interference event.

[0016] By establishing an operational interference fingerprint database and continuously accumulating waveform feature parameters of events identified as operational interference as fingerprint samples, this invention forms a reusable interference feature "baseline" when the operational anchor signal is available. In subsequent monitoring, even when the operational anchor signal is not obtained or does not meet the preset validity criteria, it can still perform similarity matching and fallback discrimination on newly identified candidate discharge events based on quantifiable features such as pulse cluster duration and preset high-frequency band energy ratio. This allows interference identification to no longer solely rely on anchor timing input and possess a "degraded usable" identification path. Consequently, it can maintain stable filtering of operational interference under conditions such as communication link jitter, timing alignment failure, or anchor missing points, reduce the spread of misjudgments caused by abnormal inputs, and improve the continuity and consistency of online diagnosis during long-term operation.

[0017] Furthermore, the steps for deriving the theoretical temperature rise trajectory specifically include: performing square integration on the load current signal within the thermal inertia lag time window to generate a resistance heat source component; performing energy accumulation or amplitude integration on the partial discharge pulse signal of the event to be verified to generate a discharge heat source component; weighting and superimposing the resistance heat source component and the discharge heat source component, and inputting them into a preset thermal inertia model containing a thermal time constant for inertial processing to output the theoretical temperature rise trajectory.

[0018] By representing the load current signal as a resistive heat source component through square integration within the thermal inertia hysteresis time window, and representing the partial discharge pulse signal of the event to be verified as a discharge heat source component through energy accumulation or amplitude integration, this invention unifies the two types of heat contributions—current-induced heat and discharge-induced heat—which have different sources and scales, into a combinable heat source input. Furthermore, weighted superposition is used to achieve equivalence processing under the same thermal power benchmark. The equivalent heat source input is further processed by an inertial model incorporating a thermal time constant, which can mechanistically characterize the hysteresis and smoothing characteristics of the "heating-heat transfer-temperature rise" process at the connection point, thereby forming a theoretical temperature rise trajectory that is comparable to the actual temperature rise response in terms of temporal morphology. This reduces the ambiguity in temperature rise interpretation caused by load fluctuations, thermal inertia hysteresis, and the transient nature of pulse events, providing a stable and repeatable reference baseline for subsequent judgments based on trajectory consistency and deviation, and improving the interpretability and consistency of diagnostic conclusions.

[0019] Further, the calculation of the trend consistency index includes: within the thermal inertia lag time window, after time alignment and normalization of the actual temperature rise trajectory and the theoretical temperature rise trajectory, calculating the cross-correlation coefficient or normalized residual between the actual temperature rise trajectory and the theoretical temperature rise trajectory to obtain the trend consistency index; the preset matching condition is that the cross-correlation coefficient is greater than a preset correlation threshold or the normalized residual is less than a preset residual threshold; the deviation is the maximum absolute difference between the actual temperature rise trajectory and the reference temperature rise trajectory within the thermal inertia lag time window.

[0020] By first aligning and normalizing the actual and theoretical temperature rise trajectories within a time window defined by thermal inertia hysteresis, this invention establishes comparability between the two trajectories under the same time reference and amplitude scale. This allows the trend consistency index to primarily reflect the trajectory shape and phase relationship rather than the absolute temperature rise level difference. Based on this, the trend consistency index is calculated using cross-correlation coefficients or normalized residuals. Using "cross-correlation coefficient greater than a preset correlation threshold" or "normalized residual less than a preset residual threshold" as matching conditions, "whether the trend is consistent" can be transformed into a calculable and reproducible criterion, thus providing a stable quantitative basis for grading. Simultaneously, the deviation is characterized by the maximum absolute difference between the actual temperature rise trajectory and the benchmark temperature rise trajectory within the time window. This can characterize the amplitude deviation of temperature rise anomalies within the same reference frame, allowing trend consistency and deviation to constrain the temperature rise response from two dimensions: "shape consistency" and "amplitude deviation," respectively. This reduces reliance on a single indicator and improves the consistency and interpretability of the conclusions.

[0021] Furthermore, the method also includes evidence accumulation and diagnostic correction steps for the observed abnormal event: constructing a sliding counting time window, counting the cumulative number of times the conclusion of the observed abnormal event is output within the sliding counting time window; acquiring the ambient humidity signal inside the ring network box, and calculating the dew point temperature based on the ambient temperature signal and the ambient humidity signal, obtaining the difference between the ambient temperature and the dew point temperature; performing a secondary judgment based on the cumulative number and the difference: when the cumulative number exceeds a preset frequency threshold and the difference is less than a preset condensation risk threshold, outputting a conclusion of condensation-related discharge hazard; when the cumulative number exceeds a preset frequency threshold and the difference is greater than or equal to the preset condensation risk threshold, outputting a conclusion of intermittent insulation defect.

[0022] By accumulating the number of observed anomalies within a sliding counting time window and introducing the dew point temperature difference calculated from ambient temperature and humidity as an environmental constraint, this invention elevates single, difficult-to-determine anomalies from "occasional" to "repeated events with statistical evidence," while also incorporating the environmental boundaries of the event occurrence into the discrimination. Thus, when the accumulated number exceeds a preset frequency threshold, the anomaly can be secondary attributed based on the relationship between the dew point temperature difference and a preset condensation risk threshold, enabling the output conclusion to form a stable shunting between condensation-related discharge hazards and intermittent insulation defects, thereby improving the convergence of the observed conclusions and the directionality of operation and maintenance.

[0023] This invention also provides a fault diagnosis system for a primary and secondary integrated ring network enclosure, comprising: The signal acquisition module is configured to acquire partial discharge pulse signals, joint temperature signals, ambient temperature signals and load current signals of the target electrical connection parts, and to obtain operation anchor point signals representing the time of grounding operation or opening and closing operation from the primary and secondary fusion terminal. The event monitoring and locking module is configured to monitor the partial discharge pulse signal and lock the trigger time of the candidate discharge event when a candidate discharge event that meets the preset triggering conditions is identified. The interference discrimination module is configured to construct an operation rejection time window based on the operation anchor signal, which is defined by a preset duration before the operation and a preset duration after the operation, and to determine whether the triggering time falls within the operation rejection time window: if it falls within the window, the candidate discharge event is determined as an operation interference event and the characteristics of the candidate discharge event are recorded; if it does not fall within the window, the candidate discharge event is determined as an event to be verified. The thermal inertia extrapolation module is configured to construct a thermal inertia lag time window based on the triggering time, generate an actual temperature rise trajectory based on the joint temperature signal and the ambient temperature signal within the thermal inertia lag time window, and extrapolate the theoretical temperature rise trajectory based on the resistance heating effect of the load current signal and the discharge heating effect of the event to be verified, combined with a preset thermal inertia model. The grading and determination module is configured to calculate the trend consistency index between the actual temperature rise trajectory and the theoretical temperature rise trajectory, and to calculate the deviation of the actual temperature rise trajectory from the reference temperature rise trajectory derived solely from the load current signal. Based on the trend consistency index and the deviation, a grading and determination module is executed to output a non-operation-related real partial discharge fault conclusion, a contact deterioration overheating fault conclusion, or an anomaly event to be observed conclusion.

[0024] The fault diagnosis system of this invention achieves modular and collaborative implementation of functions such as partial discharge, temperature and current multi-source physical quantity acquisition, event trigger locking, operation interference discrimination, thermal inertia inference, and graded judgment within the same system. This enables key timing references, window construction, and trajectory inference in the method to be implemented in a closed loop under a unified data standard and processing link. As a result, it provides stable signal access, computing capacity, and conclusion output interfaces for online operation scenarios, reduces dependence on manual interpretation and external computing environment, and facilitates engineering deployment and continuous operation in the primary and secondary fusion terminal or its associated computing units.

[0025] The present invention also provides a primary and secondary integrated ring network box, comprising: The ring main body has a primary device installed inside, and the primary device includes a target electrical connection part; A sensing component is provided corresponding to the target electrical connection part, and is used to collect the partial discharge pulse signal, connector temperature signal, ambient temperature signal and load current signal of the target electrical connection part; A primary and secondary fusion terminal is communicatively connected to the sensing component. The primary and secondary fusion terminal includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, it implements the steps of the fault diagnosis method for the primary and secondary fusion complete ring network box described above.

[0026] The integrated primary and secondary ring main unit of this invention integrates the sensing and acquisition of key operating quantities such as discharge, temperature, environment, and load current of the target electrical connection parts with the storage and processing capabilities of the primary and secondary fusion terminal within the same complete set of equipment. This enables the fault diagnosis method to achieve local data closed-loop and online calculation execution based on the existing primary equipment structure and secondary measurement and control terminal. This reduces the risks of interface inconsistency and data timing drift caused by external acquisition and decentralized deployment, improves on-site installability and operational continuity, and provides direct equipment carrier support for real-time output of diagnostic conclusions, alarm linkage, and operation and maintenance applications.

[0027] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the fault diagnosis method for the primary and secondary integrated ring network box described in any of the above claims.

[0028] (III) Beneficial effects of the present invention: The present invention establishes a transient rejection time window by utilizing the operation anchor point signal of the primary and secondary fusion terminal, and introduces a thermal inertia model containing thermal time constant to uniformly characterize and theoretically deduce the load resistance heating and discharge heating. This allows candidate discharge events to be verified by the consistency of temperature rise trend and the deviation from the benchmark under operation disturbance and thermal response lag conditions. This improves the consistency of the judgment of non-operation-related insulation discharge faults and contact deterioration overheating faults, reduces false alarms and missed alarms, and enhances the stability and reliability of the online diagnosis of complete ring network boxes under complex electromagnetic environment and dynamic load conditions. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 A flowchart illustrating the fault diagnosis method for a primary and secondary integrated ring network box provided in an embodiment of the present invention; Figure 2 The figure shows a schematic diagram of the system hardware structure and fault diagnosis logic architecture of the primary and secondary integrated ring network box provided in an embodiment of this application. Detailed Implementation

[0031] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Specific Implementation

[0032] This embodiment provides a fault diagnosis method, fault diagnosis system, ring main unit, and computer-readable storage medium for a primary and secondary integrated ring main unit. It is applicable to scenarios where the ring main unit in a distribution network is used for long-term online operation to monitor the status of key electrical connections and trigger alarms. Addressing the issue of fluctuating diagnostic conclusions due to transient pulse interference introduced by switch opening / closing or grounding operations, and the potential lag or asynchrony between partial discharge signals and temperature rise responses caused by changes in load and environmental conditions, this embodiment aims to provide verifiable, graded judgment results for candidate discharge events within a unified time-series reference and thermal inertia verification framework. This provides a stable output for on-site online diagnosis and maintenance. The following section elaborates on the fault diagnosis method and its implementation in the system, ring main unit, and computer-readable storage medium.

[0033] like Figure 2 As shown, the integrated primary and secondary ring main unit provided in this embodiment adopts an integrated structure of primary equipment and secondary intelligent unit. The whole includes two parts: the ring main unit body and the fault diagnosis system. The two are integrated and implemented through the mapping relationship of "physical acquisition front end - terminal input interface - processor logic module". The ring main unit body can adopt a fully insulated and fully enclosed gas-insulated cabinet or solid-insulated cabinet structure, and the internal primary equipment such as circuit breakers, load switches, disconnect switches, and grounding switches are arranged. The target electrical connection parts correspond to the connection nodes that are most sensitive to current carrying and insulation boundaries in the primary circuit. In this embodiment, this can be specifically reflected in the cable terminal connection structure in the cable room (such as the cable terminal cone bracket and its connection position with the conductor), the busbar lap surface in the gas chamber or busbar chamber, and the meshing contact position of the moving and stationary contacts in the switch unit. These positions are convenient for installing sensors and can better reflect the early signs of insulation degradation and poor contact.

[0034] To achieve operational status awareness of the aforementioned key nodes, the ring main unit is equipped with sensing components. These components are positioned at the corresponding electrical connection points and converge signals to the secondary instrument room. At the system architecture level, the sensing components and the input interface circuit of the primary and secondary fusion terminal together constitute the signal acquisition module of the fault diagnosis system. Specifically, the sensing components are responsible for acquiring electrical signals from on-site physical quantities, while the terminal input interface performs isolation, conditioning, and sampling. Regarding partial discharge pulse signals, the sensing components can employ ultra-high frequency (UHF) sensors or transient ground voltage sensors. UHF sensors can achieve antenna-like pickup near cable end caps or cable terminals using a built-in coupling structure and are led out via shielded coaxial cables. Transient ground voltage sensors can use capacitively coupled electrodes or surface-mounted probes on the grounded metal surface of the cabinet to acquire transient pulses caused by operation or discharge. Regarding joint temperature signals, the sensing components can employ passive wireless temperature sensors to achieve high- and low-voltage isolated temperature measurement. For example, a surface acoustic wave (SAW) sensor unit can be used as the temperature-sensitive device, and data can be transmitted back to the terminal-side read / write module via a read / write antenna. Alternatively, a local temperature probe can be used and connected via an isolated sampling link. Regarding the ambient temperature signal, this embodiment can arrange an integrated temperature and humidity sensor in a typical airflow zone within the cabinet. The ambient temperature is directly output by this sensor and sent to the terminal sampling channel. The load current signal can be multiplexed from the current transformer output at the bushing or primary circuit, and sent to the terminal after secondary sampling and isolation. The current transformer can be a measurement-grade or protection-grade transformer, specifically determined by the existing configuration of the ring main unit. Through the above arrangement, partial discharge, connector temperature, ambient temperature, and load current all have clearly defined sensor types, installation locations, and signal access paths, meeting the engineering feasibility requirements for input signals in subsequent diagnostic calculations.

[0035] In addition to the primary-side multi-source signals, the signal acquisition module also obtains operation anchor signals representing the timing of grounding or opening / closing operations from the primary and secondary fusion terminal. In this embodiment, these anchor signals can be obtained from the terminal's digital input channel or control loop current sampling channel. The digital input channel can employ optocoupler isolation or relay isolation hard-contact acquisition methods to access auxiliary switch contact change signals, switch position indication jump signals, etc. The control loop current sampling channel can obtain the abrupt change characteristics of the coil drive current through the sampling resistor of the opening / closing coil circuit, a Hall current sensor, or an equivalent current detection circuit. Simultaneously, the terminal can also read the operation command timestamp from its internal bus, relay protection device interface, or its own recorded information as the anchor source. All anchor signals from these different sources are time-marked using the terminal's unified clock and are on the same time base as the trigger time of the partial discharge pulse event, thus ensuring that the "operation timing reference" has an alignable and verifiable implementation basis at the structural and interface levels.

[0036] The primary and secondary fusion terminal, as the core intelligent unit, is installed in the instrument room. It communicates with the sensing components and carries the computing and storage resources of the fault diagnosis system. The terminal's hardware architecture includes a processor and a memory. The memory can be composed of non-volatile memory and runtime memory to store programs, parameters, and runtime cache, respectively. The processor can be a general-purpose processor with real-time sampling and event processing capabilities, and can be used in conjunction with dedicated logic units as needed. When the computer program in the memory is executed by the processor, it logically forms an event monitoring and locking module, an interference discrimination module, a thermal inertia inference module, and a hierarchical judgment module. It also forms a corresponding relationship with the terminal sampling, time stamping, buffer area, and communication interface in the data path. Specifically, the event monitoring and locking module can continuously monitor the partial discharge pulse channel using the terminal's interrupt mechanism, comparison logic, or programmable logic circuits. When the triggering conditions are met, it calls a unified clock to lock the trigger time and writes waveform segments or characteristic quantities before and after the trigger into the buffer for subsequent analysis. The interference discrimination module calls the operation anchor signal and trigger time to complete the time window-related discrimination logic and writes the waveform characteristics that need to be retained into the event record area or fingerprint database area of ​​the memory. The thermal inertia inference module calls temperature, current, and discharge characteristic related data and reads model parameters such as thermal time constant and weighting coefficient from the parameter area to form repeatable inference input. The graded judgment module completes the calculation of trend consistency and deviation related quantities under the same data caliber and publishes diagnostic conclusions and associated event identifiers through the terminal's communication interface, human-machine interface, or alarm output interface, facilitating on-site linkage and maintenance traceability. Based on the above hardware structure and system carrying relationship, the online execution and result output of the fault diagnosis method can be completed without relying on external computing devices.

[0037] Furthermore, this embodiment also involves a computer-readable storage medium, which can be at least one of a terminal built-in memory, a pluggable memory, or a remote storage space, used to store a computer program and its parameter files; after the computer program is loaded and executed by the processor, it implements the above-mentioned fault diagnosis method for the integrated primary and secondary ring network enclosure. Based on the above correspondence between hardware structure, signal access, and module carrying, the processing procedure of the fault diagnosis method will be described in detail below.

[0038] like Figure 1 As shown, in this embodiment, the fault diagnosis process uses the unified clock of the primary and secondary fusion terminals as the time base for the entire process. It synchronously collects, timestamps, and manages the partial discharge pulse signal, connector temperature signal, ambient temperature signal, and load current signal output by the sensing components, and introduces the timing reference of the switching operation on the same time axis.

[0039] In step S1, the partial discharge pulse signal can be obtained from the UHF or transient ground voltage pulse acquisition front end and input to the high-speed sampling / comparison channel of the terminal. The joint temperature signal is output by the temperature measuring element at the joint and forms a temperature sequence. The ambient temperature signal is output by the temperature and humidity sensor inside the cabinet and forms an ambient temperature sequence. The load current signal is sampled by the secondary side of the current transformer to form a current sequence. After these data enter the terminal, they are uniformly timestamped and written to the buffer according to the channel. In this embodiment, the operation anchor point signal can come from any of the following types of observable signals: the abrupt change time of the opening and closing coil current waveform, the change time of the auxiliary contact, the jump time of the switch position indication signal, and the operation command timestamp output by the relay protection device or the primary and secondary fusion terminal. When two or more types of anchor point sources are obtained at the same time, the consistency of each anchor point timestamp can be checked to form a validity criterion, thereby determining the operation time top (this symbol represents the reference time of the primary switch / grounding operation under the terminal time base) used for subsequent window construction.

[0040] In step S2, the terminal continuously monitors the partial discharge pulse signal to identify candidate discharge events and lock their trigger time ttrig (this symbol represents the timestamp when the candidate discharge event is triggered). The preset trigger conditions for the candidate discharge event can be given by engineering tuning, such as based on pulse peak amplitude, pulse energy, or pulse count per unit time. When the trigger conditions are met, the terminal freezes and caches waveform segments or feature data of a certain length before and after the trigger to support the data input required for subsequent interference discrimination, feature recording, and thermal inertia inference.

[0041] In step S3, the terminal constructs an operation exclusion time window based on the operation time *top* corresponding to the operation anchor point. Its time boundary can be represented as [*top-Tpre*, *top+Tpost*], where *Tpre* and *Tpost* represent the preset durations before and after the operation, respectively (which can be tuned based on different switch types, sampling link delays, and on-site transient duration characteristics). The terminal determines whether the trigger time *ttrig* falls within this time window; if it does, waveform characteristic conditions are further introduced for joint constraints to avoid mistakenly eliminating real defect events based solely on timing proximity. In this embodiment, the pulse cluster duration can be obtained from the time difference between the first and last pulses within the candidate event pulse cluster and compared with a preset pulse width threshold. Simultaneously, frequency domain analysis is performed on the pulse signal of the candidate event to calculate the proportion of preset high-frequency band energy to the total energy, *Rhf*, which can be calculated as follows: Rhf=Ehf / Eall Where Ehf represents the accumulated energy value within the preset high-frequency band in the frequency domain analysis results, and Eall represents the total accumulated energy value within the analysis frequency band; the frequency range of the high-frequency band and the analysis frequency band can be set according to the sensor bandwidth, sampling rate, and on-site interference spectrum characteristics. When a candidate discharge event falls within the operation rejection time window and simultaneously satisfies "pulse cluster duration less than the threshold" and "Rhf lower than the spectral energy percentage threshold", it is determined as an operation interference event and its event characteristics are recorded; if a candidate discharge event falls within the operation rejection time window but does not simultaneously meet the above waveform characteristic conditions, it is determined as an event to be verified and enters the subsequent thermal inertia verification path.

[0042] Meanwhile, to enhance usability under conditions of missing or insufficient anchor points, this embodiment establishes an operational interference fingerprint database. Feature parameters identified as operational interference events are used as fingerprint samples (including at least pulse cluster duration and Rhf). In subsequent monitoring, when no operational anchor point signal is obtained or the anchor point does not meet the validity criteria, the terminal calculates isomorphic feature vectors for newly identified candidate discharge events and performs similarity matching with the fingerprint database samples. The matching method can employ a normalized distance-based metric, for example: Sim = 1 / (1 + ||F - Fi||) Where F represents the feature vector of the current candidate event (which includes at least the pulse cluster duration and Rhf), Fi represents the feature vector of the i-th sample in the fingerprint database, and ||·|| represents the vector distance; when the similarity exceeds the preset similarity threshold, the candidate event is judged as an operation interference event, thus forming an interference identification closed loop of "anchor point discrimination as the main method and fingerprint database as the backup".

[0043] In step S4, the terminal constructs a thermal inertia hysteresis time window [ttrig, ttrig + Tlag] based on the trigger time ttrig, where Tlag represents the preset duration used to cover the hysteresis process of "discharge / heating - heat transfer - temperature rise response". Within this time window, the terminal generates both the actual temperature rise trajectory and the theoretical temperature rise trajectory: the actual temperature rise trajectory can be obtained from the difference between the junction temperature and the ambient temperature, for example: ΔTact[k] = Tjoint[k] - Tenv[k] Where ΔTact[k] represents the actual temperature rise at the k-th sampling point, Tjoint[k] represents the joint temperature sampling value, and Tenv[k] represents the ambient temperature sampling value. The input heat source of the theoretical temperature rise trajectory is characterized by both load resistance heating and discharge heating: the load resistance heating can be obtained by integrating the square of the load current to obtain the resistance heat source component, which can be discretized using: HR=Σ(I[k]^2*Δt) Wherein, HR represents the cumulative amount of resistive heat source within the thermal inertia lag time window, Σ represents the summation of the sampling points within the lag time window Wlag, I[k] represents the load current of the kth sampling point, and Δt represents the sampling period; discharge heating can be obtained by accumulating energy or integrating amplitude of the partial discharge pulse signal of the event to be verified to obtain the discharge heat source component (the specific use of energy accumulation or amplitude integration is determined by the sensor output form and calibration method). Subsequently, the resistive heat source component and the discharge heat source component are weighted and superimposed to form an equivalent heat source input. This input is then processed by a preset thermal inertial model containing the thermal time constant to output the theoretical temperature rise trajectory. In engineering implementation, the thermal inertial model can be discretized using a first-order inertial element, which means that "the current theoretical temperature rise is jointly determined by the theoretical temperature rise at the previous moment and the current equivalent heat source." The thermal time constant is used to characterize the hysteresis and smoothness of the heating and heat transfer at the connection point. The weights and thermal parameters can be tuned according to the voltage level, structural heat capacity, sensor calibration results, and typical load conditions to make the theoretical trajectory comparable to the actual temperature rise response in terms of time sequence.

[0044] In step S5, the terminal performs time alignment and normalization on the actual temperature rise trajectory and the theoretical temperature rise trajectory within the thermal inertia lag time window, so that the trend consistency assessment mainly reflects the trajectory shape and phase relationship rather than the absolute temperature rise level difference. The trend consistency index can be calculated using the cross-correlation coefficient, and one implementation of the cross-correlation coefficient is as follows: ρ=[Σ(ΔT_act_norm[k]*ΔT_th_norm[k])] / [√Σ(ΔT_act_norm[k]^2)*√Σ(ΔT_th_norm[k]^2)] Where ρ represents the trend consistency index, Σ represents the summation over all sampling points, and ΔT_act_norm[k] and ΔT_th_norm[k] represent the aligned and normalized actual temperature rise sequence and theoretical temperature rise sequence, respectively. The preset matching condition can correspond to "the cross-correlation coefficient is greater than the preset correlation threshold", or it can be achieved by the normalized residual being less than the preset residual threshold (the normalized residual can be obtained by ratioing the cumulative difference between the two normalized trajectories to the benchmark). The deviation is used to characterize the degree of deviation of the actual temperature rise from the pure load benchmark, where the benchmark temperature rise trajectory is derived by considering only the heating caused by the load current, and the deviation can be obtained by the maximum absolute difference between the two trajectories within the thermal inertia lag time window. To meet the criterion that "the event to be verified continues to exist within the thermal inertia lag time window", the terminal can count the number of effective pulses or the effective duty cycle of the partial discharge pulse signal exceeding the threshold within this time window to confirm that the event has a continuous contribution to the thermal response. Ultimately, the terminal performs a graded judgment and outputs conclusions on non-operation-related real partial discharge faults, contact deterioration overheating faults, or anomalies to be observed, based on whether the trend consistency index meets the preset matching conditions, whether the deviation exceeds the preset overheating threshold, and the persistence conditions. This ensures that the conclusions are established on a calculable and verifiable physical consistency verification link.

[0045] When the output is a conclusion of an observed anomaly event, this embodiment further enters the evidence accumulation and diagnostic correction process: the terminal constructs a sliding counting time window and counts the cumulative number of conclusions of the observed anomaly event within the window, which is used to elevate a single anomaly that is difficult to define into a recurring event with statistical evidence; at the same time, the ambient humidity signal inside the ring network box is acquired, and the dew point temperature is calculated in combination with the ambient temperature signal, and the difference between the ambient temperature and the dew point temperature is used as the environmental constraint quantity for condensation risk. The dew point temperature can be obtained by converting the ambient temperature and relative humidity using a dew point calculation model commonly used in engineering (the model parameters can be preset in the terminal and matched with the sensor range), thereby obtaining the "difference between the ambient temperature and the dew point temperature"; when the cumulative number exceeds the preset frequency threshold and the difference is less than the preset condensation risk threshold, the conclusion of condensation-related discharge hazard is output; when the cumulative number exceeds the preset frequency threshold and the difference is greater than or equal to the preset condensation risk threshold, the conclusion of intermittent insulation defect is output. By combining the cumulative number of observations with the dew point difference for secondary determination, the observed conclusions can achieve more stable attribution and diversion under the constraints of repeatability evidence and environmental boundaries, and provide clearer conclusions for subsequent operation and maintenance.

[0046] The above are preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A fault diagnosis method for a primary and secondary integrated ring network box, characterized in that, Includes the following steps: S1. Collect partial discharge pulse signals, joint temperature signals, ambient temperature signals, and load current signals of the target electrical connection parts; and obtain the operation anchor point signal representing the time of grounding operation or opening and closing operation from the primary and secondary fusion terminal. S2. Monitor the partial discharge pulse signal, and when a candidate discharge event that meets the preset triggering conditions is identified, lock the triggering time of the candidate discharge event; S3. Based on the operation anchor signal, construct an operation rejection time window defined by a preset time before operation and a preset time after operation; determine whether the triggering time falls within the operation rejection time window: if it does, then determine the candidate discharge event as an operation interference event and record the characteristics of the candidate discharge event. If the candidate discharge event does not fall into the category, it will be identified as an event to be verified. S4. Construct a thermal inertia hysteresis time window based on the triggering time; Within the thermal inertia hysteresis time window, an actual temperature rise trajectory is generated based on the joint temperature signal and the ambient temperature signal; and based on the resistance heating effect of the load current signal and the discharge heating effect of the event to be verified, the theoretical temperature rise trajectory is deduced in combination with the preset thermal inertia model. S5. Calculate the trend consistency index between the actual temperature rise trajectory and the theoretical temperature rise trajectory, and calculate the deviation of the actual temperature rise trajectory from the reference temperature rise trajectory derived solely from the load current signal; perform a graded judgment based on the trend consistency index and the deviation: when the trend consistency index meets the preset matching condition and the event to be verified persists within the thermal inertia hysteresis time window, output a non-operation-related real partial discharge fault conclusion; when the trend consistency index does not meet the preset matching condition and the deviation exceeds the preset overheating threshold, output a contact degradation overheating fault conclusion; otherwise, output an observation anomaly event conclusion.

2. The fault diagnosis method for the primary and secondary integrated ring network box according to claim 1, characterized in that, The operation anchor signal includes at least one of the following signals: the abrupt change time of the opening and closing coil current waveform of the circuit breaker or load switch; the change time of the auxiliary contact of the grounding switch or disconnecting switch; the jump time of the switch position indication signal; and the operation command timestamp output by the relay protection device or the primary and secondary fusion terminal.

3. The fault diagnosis method for the primary and secondary integrated ring network box according to claim 2, characterized in that, To determine the candidate discharge event as an operational interference event, the following waveform characteristic conditions must be met simultaneously: the duration of the pulse cluster of the candidate discharge event is less than a preset pulse width threshold; and the proportion of the preset high-frequency band energy to the total energy obtained by frequency domain analysis of the pulse signal of the candidate discharge event is lower than a preset spectral energy proportion threshold; if the candidate discharge event falls into the operational rejection time window but does not simultaneously meet the above waveform characteristic conditions, it is determined as an event to be verified.

4. The fault diagnosis method for the primary and secondary integrated ring network box according to claim 3, characterized in that, The method further includes the steps of constructing an operation interference fingerprint database and fallback identification: establishing an operation interference fingerprint database, and storing the waveform feature parameters of events identified as operation interference events as fingerprint samples in the operation interference fingerprint database, wherein the waveform feature parameters include at least the duration of the pulse cluster and the proportion of the energy of the preset high-frequency band to the total energy; in subsequent monitoring, when the operation anchor signal is not obtained or the operation anchor signal does not meet the preset validity criteria, the waveform feature parameters of newly identified candidate discharge events are matched with the fingerprint samples in the operation interference fingerprint database; if the matching similarity exceeds the preset similarity threshold, the candidate discharge event is identified as an operation interference event.

5. The fault diagnosis method for the primary and secondary integrated ring network box according to claim 1, characterized in that, The steps for deriving the theoretical temperature rise trajectory specifically include: performing square integration on the load current signal within the thermal inertia lag time window to generate a resistance heat source component; performing energy accumulation or amplitude integration on the partial discharge pulse signal of the event to be verified to generate a discharge heat source component; weighting and superimposing the resistance heat source component and the discharge heat source component, and inputting a preset thermal inertia model containing a thermal time constant for inertial processing to output the theoretical temperature rise trajectory.

6. The fault diagnosis method for the primary and secondary integrated ring network box according to claim 1, characterized in that, The calculation of the trend consistency index includes: within the thermal inertia lag time window, after time alignment and normalization of the actual temperature rise trajectory and the theoretical temperature rise trajectory, calculating the cross-correlation coefficient or normalized residual between the actual temperature rise trajectory and the theoretical temperature rise trajectory to obtain the trend consistency index; the preset matching condition is that the cross-correlation coefficient is greater than a preset correlation threshold or the normalized residual is less than a preset residual threshold; the deviation is the maximum absolute difference between the actual temperature rise trajectory and the reference temperature rise trajectory within the thermal inertia lag time window.

7. The fault diagnosis method for the primary and secondary integrated ring network box according to any one of claims 1 to 6, characterized in that, The method further includes evidence accumulation and diagnostic correction steps for the observed abnormal event: constructing a sliding counting time window, counting the cumulative number of times the conclusion of the observed abnormal event is output within the sliding counting time window; acquiring the ambient humidity signal inside the ring network box, and calculating the dew point temperature based on the ambient temperature signal and the ambient humidity signal, obtaining the difference between the ambient temperature and the dew point temperature; performing a secondary judgment based on the cumulative number and the difference: when the cumulative number exceeds a preset frequency threshold and the difference is less than a preset condensation risk threshold, outputting a conclusion of condensation-related discharge hazard; when the cumulative number exceeds a preset frequency threshold and the difference is greater than or equal to the preset condensation risk threshold, outputting a conclusion of intermittent insulation defect.

8. A fault diagnosis system for a primary and secondary integrated ring network box, characterized in that, include: The signal acquisition module is configured to acquire partial discharge pulse signals, joint temperature signals, ambient temperature signals and load current signals of the target electrical connection parts, and to obtain operation anchor point signals representing the time of grounding operation or opening and closing operation from the primary and secondary fusion terminal. The event monitoring and locking module is configured to monitor the partial discharge pulse signal and lock the trigger time of the candidate discharge event when a candidate discharge event that meets the preset triggering conditions is identified. The interference discrimination module is configured to construct an operation rejection time window based on the operation anchor signal, which is defined by a preset time before the operation and a preset time after the operation, and to determine whether the triggering time falls within the operation rejection time window: if it falls within the window, the candidate discharge event is determined as an operation interference event and the characteristics of the candidate discharge event are recorded. If the candidate discharge event does not fall into the category, it will be identified as an event to be verified. The thermal inertia extrapolation module is configured to construct a thermal inertia lag time window based on the triggering time, generate an actual temperature rise trajectory based on the joint temperature signal and the ambient temperature signal within the thermal inertia lag time window, and extrapolate the theoretical temperature rise trajectory based on the resistive heating effect of the load current signal and the discharge heating effect of the event to be verified, combined with a preset thermal inertia model. The grading and determination module is configured to calculate the trend consistency index between the actual temperature rise trajectory and the theoretical temperature rise trajectory, and to calculate the deviation of the actual temperature rise trajectory from the reference temperature rise trajectory derived solely from the load current signal. Based on the trend consistency index and the deviation, a grading and determination module is executed to output a non-operation-related real partial discharge fault conclusion, a contact deterioration overheating fault conclusion, or an anomaly event to be observed conclusion.

9. A primary and secondary integrated ring network box, characterized in that, include: The ring main body has a primary device installed inside, and the primary device includes a target electrical connection part; A sensing component is provided corresponding to the target electrical connection part, and is used to collect the partial discharge pulse signal, connector temperature signal, ambient temperature signal and load current signal of the target electrical connection part; A primary and secondary fusion terminal is communicatively connected to the sensing component. The primary and secondary fusion terminal includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, it implements the steps of the fault diagnosis method for the primary and secondary fusion complete ring network box as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the fault diagnosis method for the primary and secondary integrated ring network box as described in any one of claims 1 to 7.

Images