Intelligent anti-three-error monitoring system for secondary current loop of transformer substation

Abstract

The application discloses a substation secondary current loop intelligent anti-three-mistake monitoring system and belongs to the field of secondary equipment monitoring of a power system. The system comprises an electromagnetic induction monitoring module, a continuous piece state detection module, a three-mistake analysis and judgment module, a logic locking module and a pre-power transmission checking module. The electromagnetic induction monitoring module non-contact collects current values of each loop through an open high-precision micro current transformer; the continuous piece state detection module detects the on-off state of the test terminal continuously; the three-mistake analysis and judgment module executes mistake touch judgment, mistake connection judgment and mistake setting judgment; the logic locking module sends a locking instruction to a five-prevention system when detecting a three-mistake event; and the pre-power transmission checking module automatically verifies the continuous piece state of all current loops before power transmission. The application can monitor the state of the secondary current loop in real time, effectively prevent CT open circuit damage to primary equipment caused by human being's failure to combine the continuous pieces, and guarantee the safe and stable operation of the substation.

Description

Technical Field

[0001] This invention relates to the monitoring of secondary equipment in power systems, and more particularly to an intelligent monitoring system for preventing three types of errors in the secondary current circuit of a substation. Background Technology

[0002] The secondary current circuit of a substation is a crucial signal channel for relay protection, measurement and metering, and automation devices, and its integrity directly affects the safe and stable operation of the power grid. In recent years, the State Grid Corporation has experienced several equipment tripping incidents caused by secondary circuit maintenance work, exposing prominent problems such as weakened skills among maintenance personnel and insufficient technical prevention measures. In substation secondary work, relay protection "three errors" (accidental contact, accidental connection, and accidental setting) accidents occur frequently, among which the continuous leakage restoration of secondary current circuits is a typical hidden danger: during maintenance, for safety reasons, the current circuit is disconnected in a continuous manner. If it is not restored in time before energizing, it will cause the secondary side of the current transformer (CT) to open, generating high voltage and damaging primary equipment. In severe cases, it can cause arcing short circuits and equipment burnout.

[0003] In existing technologies, monitoring of secondary current loops mainly focuses on fault detection. For example, Chinese patent CN117269843A discloses an online monitoring method for the neutral line operating status of a secondary current loop. This method uses a high-precision sensor to collect the neutral line current, processes it using a composite filtering algorithm to obtain the fundamental component, and combines outlier deviation linearity and continuous dynamic trend deviation to detect neutral line breaks or loose connections. However, this method only monitors the operating status of a single conductor in the neutral line, failing to cover the status of all conductors in the current loop, and cannot prevent accidents caused by human error from a maintenance perspective.

[0004] Chinese patent CN113671233B discloses a method for judging the operating status of the secondary circuit based on the harmonic characteristics of a current transformer. By measuring the fluctuation amplitudes of the third and fifth harmonics in the secondary current, it determines whether the secondary circuit of the current transformer has an open circuit or saturation. This method can only identify open circuit faults that have already occurred, and is a post-event detection method. It cannot detect or prevent three types of faults during maintenance in advance, nor does it have the interlocking capability to be linked with a five-prevention system.

[0005] Chinese patent CN121385726A discloses a distributed monitoring device and method for locating anomalies in the secondary circuit of the protection current in a substation. It uses distributed small current transformers to collect the current of the A / B / C / N / grounding wires in real time, and incorporates multiple fault criteria for online diagnosis of faults such as CT phase line open circuit, winding-side grounding, load-side grounding, two-point grounding of the N line, and N line open circuit. This device focuses on fault location and diagnosis, but does not address the prevention of human error during maintenance operations, nor does it propose pre-energization verification or logic interlocking mechanisms.

[0006] Existing secondary current loop monitoring technologies mainly focus on detection and location after a fault occurs, lacking the ability to prevent three types of errors throughout the entire maintenance process, and failing to achieve a complete protection chain of "prevention before the event, interlocking during the event, and power-on verification". Summary of the Invention

[0007] Purpose of the invention: The purpose of this invention is to provide an intelligent monitoring system for preventing human error in the secondary current circuit of a substation, which aims to solve the technical problem that existing monitoring technologies cannot prevent human error accidents during maintenance operations, and to realize real-time monitoring and logic interlocking protection of the status of the secondary current circuit.

[0008] Technical solution: Intelligent anti-misoperation monitoring system for secondary current circuits in substations, including: The electromagnetic induction monitoring module is installed on the current loop conductors in the terminal boxes, control cabinets and protection panels of the secondary current loop in the substation. It includes an open-type high-precision miniature current transformer for non-contact real-time acquisition of the current value of each loop conductor. A joint status detection module is installed on the test terminal joint of the current loop. It includes a miniature position sensor, which is fixed on the joint base. When the joint is in the insertion position, it outputs a first level signal, and when the joint is in the withdrawal position, it outputs a second level signal. The three-error analysis and judgment module is connected to the electromagnetic induction monitoring module and the continuous state detection module respectively, and performs three-error analysis: The accidental contact judgment is based on the system operating conditions and work ticket information to build a desired current model. The real-time current value is compared with the desired current value. When the current deviation exceeds the preset threshold and the duration exceeds the preset duration, it is judged as an accidental contact event. The system detects incorrect connections by constructing the current circuit topology matrix based on the connected and unconnected status of the circuit, comparing it with the authorized configuration topology matrix, and determining that a misconnection event occurs when there is a discrepancy. The system for determining incorrect settings involves reading the protection device's setting parameters through the communication interface and comparing them with the authorized setting values. If the deviation exceeds the allowable range, it is determined to be an incorrect setting event. The logic interlocking module is connected to the three-error analysis and judgment module and the substation five-prevention system. When the three-error event is detected, it sends an interlocking command to the five-prevention system. The pre-power-on verification module is connected to the electromagnetic induction monitoring module and the interconnection status detection module. Before the power-on operation, it automatically traverses all monitoring nodes to verify that all interconnections of each circuit are in the working state and that there are no open circuits in the current circuit.

[0009] Furthermore, the electromagnetic induction monitoring module also includes: The signal conditioning circuit is connected to the open-type high-precision miniature current transformer and is used to amplify and filter the acquired current signal to remove DC and harmonic components. An analog-to-digital converter, connected to the signal conditioning circuit, is used to convert analog signals into digital signals; A communication interface, connected to the analog-to-digital converter, is used to upload digitized current data to the three-error analysis and judgment module.

[0010] Furthermore, the continuous-piece status detection module also includes: Hall effect sensors, placed near the rotating shaft of the continuous sheet, are used to detect changes in the mechanical position of the continuous sheet. The status coding circuit is connected to the Hall sensor, assigns a unique address code to each connected piece, and uploads the connection status of the connected piece to the address code to the error analysis and judgment module.

[0011] Furthermore, in the accidental contact determination, the method for constructing the expected current model is as follows: Based on the current system operation mode, obtain the primary load current and calculate the expected secondary current value Ie by combining the current transformer ratio; The current deviation is determined by the condition that |Ia-Ie|>k×Ie and lasts for a time t0, where Ia is the real-time current value, k is the deviation coefficient with a value range of 0.1~0.3, and t0 is the duration threshold with a value range of 50ms~200ms.

[0012] Furthermore, in the misconnection judgment, the method for constructing the current loop topology matrix is ​​as follows: The status of each monitoring node's continuous deployment and withdrawal is encoded into binary values, with deployment being 1 and withdrawal being 0, forming a status vector S; Based on the pre-stored loop connection table, the state vector S is mapped to the topology matrix T, where the element Tij represents the connection state between node i and node j. The authorized configuration topology matrix is ​​the standard topology matrix corresponding to the current work ticket.

[0013] Furthermore, the logic interlocking module is linked with the five-prevention system through both hard contact output and communication messages; When a triple fault event is detected, the logic interlocking module simultaneously outputs a hard contact interlocking signal to the operation circuit of the relevant equipment, and sends the interlocking reason and location information to the backend of the five-prevention system via communication messages.

[0014] Furthermore, the verification process of the pre-power-on verification module is as follows: Upon receiving the power supply operation command, a status query command is sent to all connected status detection modules; Collect the status information of all connected areas within a preset time to verify whether they are all in the operational state; Simultaneously, the current data of the electromagnetic induction monitoring module is read to verify whether there is an open circuit. If all verifications pass, a verification pass signal is output, allowing power-on operation; if an abnormality is found, an alarm message is output and power-on operation is blocked.

[0015] Furthermore, it also includes a self-diagnostic module for: The electromagnetic induction monitoring module is periodically checked for operation, and an alarm is issued when a sensor disconnection or abnormal signal is detected. Monitor the communication status of the continuous area status detection module and issue an alarm when the communication is interrupted for more than a preset time; Record all alarms and event information to form an operation log.

[0016] This invention also provides an intelligent anti-malfunction monitoring method for secondary current circuits in substations, comprising the following steps: S1: Install electromagnetic induction monitoring modules on the current loop conductors at the terminal boxes, control cabinets and protection panels of the secondary current loop in the substation, and install a connection status detection module on the test terminal connection of the current loop. S2: The electromagnetic induction monitoring module collects the current value of each circuit conductor in real time through an open-type high-precision miniature current transformer in a non-contact manner. The joint status detection module detects the connection status of each joint in real time through a miniature position sensor and uploads the current value and joint connection status data to the three error analysis and judgment module. S3: The error analysis and judgment module performs error analysis: Accidental contact judgment: Construct a desired current model based on the current system operating conditions and work order information, compare the real-time current value with the desired current value, and determine an accidental contact event when the current deviation exceeds a preset threshold and the duration exceeds a preset duration; Misconnection detection: Construct the current circuit topology matrix based on the connected circuit activation / deactivation status, compare it with the authorized configuration topology matrix, and determine the misconnection event when they are inconsistent; Error setting judgment: The protection device setting parameters are read through the communication interface and compared with the authorized setting values. When the deviation exceeds the allowable range, it is judged as an error setting event. S4: When a three-error event is detected, the logic interlocking module sends an interlocking command to the five-prevention system through hard contact output and communication messages to prevent dangerous operation of the relevant equipment; S5: Before the power-on operation, the pre-power-on verification module automatically traverses all monitoring nodes to verify that all circuit connections are in the working state and that there are no open circuits in the current circuit, and generates a verification report.

[0017] Beneficial effects: (1) Achieve full protection against three errors: Through dual sensing of electromagnetic induction monitoring and continuous status detection, combined with the analysis and judgment of three errors and logical interlocking, a complete protection chain of "prevention before the event, interlocking during the event, and power-on verification" is constructed to fundamentally solve the problem of preventing human error accidents during maintenance operations.

[0018] (2) Non-contact real-time monitoring: Using an open-type high-precision miniature current transformer, the current value can be collected in real time without disconnecting the current loop, without affecting the normal protection function, and at the same time, abnormal current changes can be detected in a timely manner.

[0019] (3) Automatic verification before power supply: Before power supply operation, all monitoring nodes are automatically traversed to verify the connection status and integrity of the current loop, so as to avoid the CT open circuit due to leakage connection and ensure power supply safety.

[0020] (4) Five-prevention linkage interlock: It is linked with the five-prevention system through hard contacts and communication messages. When the risk of three errors is detected, the relevant operation is immediately locked to prevent dangerous operation from being performed.

[0021] (5) Self-diagnostic capability: The system has a complete self-diagnostic function, which can detect sensor faults and communication anomalies in a timely manner, ensuring the reliable operation of the monitoring system. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall architecture of the intelligent anti-three-error monitoring system for substation secondary current circuits of the present invention; Figure 2 This is a flowchart illustrating the analysis logic of the error analysis and judgment module of this invention. Figure 3 This is a flowchart of the verification process for the pre-power-on verification module of this invention. Detailed Implementation

[0023] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1

[0025] like Figure 1 As shown, this embodiment provides an intelligent anti-malfunction monitoring system for secondary current loops in substations, applied to the monitoring of secondary current loops in relay protection of a 220kV substation. The substation comprises four line bays and two main transformer bays, with a total of six protection devices. Each protection device has an independent current loop, which needs to be disconnected from the main circuit during maintenance and restored before energization.

[0026] The system includes an electromagnetic induction monitoring module, a continuous status detection module, a three-error analysis and judgment module, a logic interlocking module, a pre-power-on verification module, and a self-diagnosis module.

[0027] The electromagnetic induction monitoring module uses open-type high-precision miniature current transformers (accuracy class 0.2, rated ratio 5A / 5mA), installed on the A, B, and C three-phase current loop conductors and the N line in the terminal box of each bay. Each monitoring point has four transformers (one each for A, B, C, and N), and the entire substation has a total of 6 bays × 4 transformers × 6 monitoring points (one each in the terminal box, control cabinet, and protection panel) = 144 transformers. The output signal of each transformer is processed by a signal conditioning circuit (gain amplified 20 times, bandpass filtered 20Hz~1kHz to remove DC and high-frequency harmonics), then converted into a digital signal by a 16-bit ADC at a 4kHz sampling rate, and uploaded to the three-phase error analysis and judgment module via an RS-485 bus.

[0028] The interconnection status detection module uses Hall effect sensors (model SS49E, linear output type) installed near the rotating shaft of each test terminal interconnection. When the interconnection is in the engaged position (closed), the Hall effect sensor detects the magnetic field of the magnet and outputs a high level (3.3V); when the interconnection is disengaged (open), it outputs a low level (0V). The status encoding circuit assigns an 8-bit address code to each interconnection (the first 4 bits are the interval number, and the last 4 bits are the interconnection sequence number), and uploads the interconnection address and engaged / disengaged status to the error analysis and judgment module via the CAN bus. A total of 96 interconnection status detection points are set up throughout the substation.

[0029] The three-error analysis and judgment module uses an ARM Cortex-M7 microcontroller (480MHz main frequency) to receive current data from the electromagnetic induction monitoring module and status data from the interconnection status detection module in real time, and performs three-error analysis. The false contact judgment uses the expected current model: it obtains the current primary load current from the SCADA system (e.g., the load current of phase A of the line is 240A), and calculates the expected secondary current value Ie = 240 / 120 = 2.0A based on the CT ratio (600 / 5 = 120); it sets the deviation coefficient k = 0.2 and the duration threshold t0 = 100ms, then the judgment condition is |Ia - 2.0| > 0.4A and lasts for 100ms. The false connection judgment uses topology matrix comparison: the status of 96 interconnections is encoded into a 96-dimensional binary vector S, mapped to a 96×96 topology matrix T according to the pre-stored loop connection relationship, and compared with the standard matrix corresponding to the current work order; if they are inconsistent, an alarm is triggered. The system detects incorrect settings by reading the protection device settings through the communication interface (IEC61850-9-2 protocol) and comparing them with the authorized setting database. If the deviation exceeds ±5%, an alarm is triggered.

[0030] The logic interlocking module is linked to the five-prevention system in two ways: the hard contact output uses a normally closed relay, which de-energizes and disconnects when three false events are detected, directly cutting off the operating power of the relevant equipment; the communication message uses IEC 61850 GOOSE message, which sends the interlocking reason code (01=false contact, 02=false connection, 03=false setting) and location information (interval number + equipment number) to the five-prevention backend.

[0031] Upon receiving the power-on operation command, the pre-power-on verification module sends a status query command to all 96 interconnected status detection modules via the CAN bus. Within 500ms, it collects the status of all interconnected modules to verify whether they are all in the active state. Simultaneously, it reads the current data of 144 electromagnetic induction transformers to verify whether there is an open circuit (the current in one phase is zero, but there is current in the adjacent phase). If all verifications pass, it outputs a verification pass signal (relay closed) to allow the power-on operation. If an abnormality is found, it outputs an alarm message and blocks the power-on operation.

[0032] The self-diagnostic module checks the working status of the electromagnetic induction monitoring module every 10 seconds (checking whether communication is normal and whether the current value is within a reasonable range), and checks the communication status of the continuous status detection module every 5 seconds. When communication is interrupted for more than 3 seconds, an alarm is issued. All alarm and event information is recorded on the SD card to form a timestamped operation log.

[0033] Example 2

[0034] like Figure 2 As shown in the figure, this embodiment details the accidental collision judgment logic of the three-error analysis and judgment module.

[0035] The core idea of ​​accidental contact detection is that during maintenance work, if a worker accidentally touches a live conductor in a current loop, the current in that loop will suddenly change (either increase suddenly or drop suddenly to zero). The system constructs a model of the expected current and compares the actual current with the expected current in real time to detect anomalies promptly.

[0036] The method for constructing the desired current model is as follows: Step 1: Obtain the current operating mode (e.g., double busbar operation, single busbar operation, etc.) and the primary load current (active power P, reactive power Q, line voltage U) of each bay from the substation SCADA system. .

[0037] Step 2: Obtain the CT ratio n (e.g., 600 / 5=120) based on the parameters on the current transformer nameplate, and calculate the expected secondary current value Ie=I1 / n.

[0038] Step 3: Determine which bays are under maintenance based on the current work order information. For bays under maintenance, the current loop connection has been disconnected, and the expected current is zero; for bays in normal operation, the expected current is Ie.

[0039] Step 4: Collect the current value Ia of each circuit in real time and calculate the deviation ΔI=|Ia-Ie|.

[0040] Step 5: Determine if the false collision condition is met: ΔI > k × Ie and lasts for t0 seconds. Where k is the deviation coefficient, which is taken as 0.1~0.3 based on field operation experience (0.2 in this embodiment), and t0 is the duration threshold, which is taken as 50ms~200ms (100ms in this embodiment), used to filter out transient interference.

[0041] Step 6: If the accidental contact condition is met, immediately trigger an alarm, record the accidental contact time, interval number, phase, and current surge amplitude, and simultaneously send a lockout command to the logic lockout module.

[0042] Taking a specific scenario as an example: A 220kV line bay is operating normally, with a primary side load current of 360A and a CT ratio of 600 / 5=120. Therefore, the expected secondary side current Ie=360 / 120=3.0A. During a test of an adjacent bay, maintenance personnel accidentally touched the A-phase current loop conductor of this line, causing the A-phase current to suddenly drop to zero. The system detected an A-phase current deviation ΔI=|0-3.0|=3.0A>0.2×3.0=0.6A, which lasted for 100ms. This was determined to be a false contact event, and an alarm was immediately issued, locking related operations.

[0043] The following special cases should also be considered when determining accidental touches: (1) Load fluctuations during normal system operation: When a short-circuit fault occurs or a large load is switched on, the primary current will change significantly. At this time, the system obtains the latest primary current value from SCADA and dynamically updates the expected current model to avoid misjudgment.

[0044] (2) Current loop of maintenance interval: When the connecting piece of a certain interval has been removed, the expected current of the interval is zero. If current is detected in the interval at this time (which may be caused by induced current or incorrect wiring), it is judged as abnormal.

[0045] (3) Simultaneous changes of multiple phases: If the three phase currents change by the same proportion at the same time, it may be a change in system load rather than a false alarm. In this case, the alarm level should be reduced or no alarm should be issued.

[0046] Example 3

[0047] This embodiment details the error detection logic and error setting logic of the three error analysis and judgment module.

[0048] The core idea behind misconnection detection is that during maintenance work, operators need to either disconnect or engage specific interconnects. If the disconnection / engagement operation is inconsistent with the work order requirements (e.g., disconnections that should have been disconnected were not, or engagements that should have been engaged were not), then it is considered a misconnection.

[0049] The method for identifying incorrect connections uses a topology matrix comparison, and the specific steps are as follows: Step 1: Pre-establish the loop connection table for each bay. Taking a certain line bay as an example, its current loop includes the following nodes: CT secondary winding output terminals S1 and S2, A connecting piece K1, B connecting piece K2, C connecting piece K3, N line connecting piece K4 on the test terminal block, and protection device current input terminals IA, IB, IC, and IN. The normal connection relationship is: S1→K1→IA, S2→K4→IN, K2→IB, K3→IC.

[0050] Step 2: Encode the status of the connected sections into binary values. Each connected section is 1 when engaged and 0 when withdrawn. For example, during normal operation, all connected sections are engaged, and the status vector is S=[1,1,1,1]; during maintenance, K1~K4 are withdrawn, and the status vector is S=[0,0,0,0].

[0051] Step 3: Construct the topology matrix T based on the state vector S and the loop connection relationships. The matrix element Tij represents the connectivity state between node i and node j (1 = connected, 0 = disconnected). Taking the normal operation state as an example, the connection between S1 and IA in T is 1, and the connection between S1 and IB is 0 (because S1 and IB are not connected when K2 is disconnected).

[0052] Step 4: Obtain the standard topology matrix T0 corresponding to the current work order. The work order clearly specifies which connected areas need to be withdrawn and which need to be put into operation, and generates the standard state vector S0 and the standard topology matrix T0 accordingly.

[0053] Step 5: Compare the real-time status matrix T with the standard matrix T0. If T=T0, the interconnection operation is correct; if T≠T0, find the difference element, locate the incorrectly connected interconnection number and phase, and issue an alarm.

[0054] For example, consider a specific scenario: A maintenance work order for a certain line bay requires the removal of connector K1 (phase A) and connector K4 (phase N), while keeping connectors K2 (phase B) and K3 (phase C) engaged. The standard state vector is S0 = [0,1,1,0]. However, the actual detected state vector is S = [0,1,0,0] (K3 is also removed). A comparison reveals an inconsistency in K3's state, leading the system to determine that K3 has been mistakenly removed and issue an alarm prompting the maintenance personnel to check connector K3.

[0055] The core principle of error setting judgment is that the setting parameters of the protection device must be consistent with the authorized setting values ​​issued by the dispatching department. If maintenance personnel modify the setting values ​​during the commissioning process but fail to restore them, or if the settings are incorrectly set, it will lead to malfunction or failure of the protection to operate.

[0056] The specific methods for judging incorrect settings are as follows: Step 1: Read the current setting parameters of the protection device (such as overcurrent protection setting Iset, time setting Tset, zero-sequence current setting I0set, etc.) through the IEC 61850-9-2 communication interface.

[0057] Step 2: Obtain the standard setting parameters of the device from the authorized setting database.

[0058] Step 3: Compare item by item and calculate the deviation rate δ = |Iset_current - Iset_auth| / Iset_auth × 100%.

[0059] Step 4: If any deviation rate exceeds the allowable range (set to ±5% in this embodiment), it is determined to be an incorrect setting event and an alarm is issued.

[0060] For example, in a specific scenario: the overcurrent protection setting authorization value of a certain line is 4.0A. During maintenance and debugging, it was mistakenly changed to 3.5A. The deviation rate δ=|3.5-4.0| / 4.0×100%=12.5%>5%. The system judges it as an incorrect setting event, issues an alarm and blocks the power supply operation.

[0061] Example 4

[0062] like Figure 3 As shown in the figure, this embodiment details the verification process of the pre-power-on verification module.

[0063] Pre-energization verification is a crucial step in preventing open circuits in current transformers (CTs). After maintenance work is completed, before restoring power, it must be ensured that all current circuit connections are correctly engaged and that the current circuits are complete and free of open circuits. Traditional methods rely on manual inspection, which is prone to omissions; this invention, through automated verification, fundamentally eliminates the risk of human error.

[0064] The specific procedure for pre-power-on verification is as follows: Step 1: The operator initiates a power supply operation application through the five-prevention system backend, and the system automatically triggers the verification process.

[0065] Step 2: Before powering on, the verification module sends a status query command to all connected status detection modules via the CAN bus (broadcast address 0xFF, command code 0x01).

[0066] Step 3: After receiving the query command, each cluster status detection module packages and sends back the address code and current deployment / retraction status of its cluster. The verification module collects the status information of all 96 clusters within 500ms.

[0067] Step 4: The verification module checks whether all connected sections are in the active state. If a connected section is found to be in the deactivated state, its address code (interval number + connected section number) is recorded, indicating that the connected section has not been restored. An alarm message is output: "Connected section XX in interval XX is not in the active state", and the power supply operation is blocked.

[0068] Step 5: Simultaneously, the verification module reads the current data from the electromagnetic induction monitoring module to verify whether there is an open circuit in each loop. The judgment method is as follows: For the four wires A / B / C / N in each interval, if the current in a certain wire is zero while the adjacent wire has current, then the wire is determined to be open; if the current in all four wires is not zero and the vector sum is zero (|IA+IB+IC+IN|<0.05A), then the loop is determined to be normal.

[0069] Step Six: If all connected sections are engaged and no current loops are open, the verification module outputs a verification pass signal (relay closes), allowing the power supply operation to continue. Simultaneously, a verification report is generated, including: verification time, all connected section statuses, current values ​​for each loop, and verification conclusions. This report is saved to an SD card and uploaded to the five-prevention backend.

[0070] Step 7: If the verification fails, the verification module outputs an alarm message and blocks the power supply operation. The operator needs to troubleshoot the problem based on the alarm message. After the problem is resolved, a new power supply application will be initiated, and the system will execute the verification process again.

[0071] Taking a specific scenario as an example: After maintenance of a 220kV line bay is completed, the operator requests power restoration. The verification module sends a query command to 96 interconnection status detection modules and receives responses from 95 interconnections within 500ms. Among them, the status of interconnection number 47 (phase B of bay 3) is "out of service". At the same time, data from the electromagnetic induction monitoring module is read, and it is found that the current of phase B of bay 3 is zero, while phases A and C have current, indicating that the current loop of phase B of bay 3 is open. The verification module outputs an alarm: "Interconnection of bay B of bay 3 not engaged, current loop open", blocking the power restoration operation. The operator checks and finds that the interconnection of bay B of bay 3 is indeed not restored. After engaging the interconnection, the operator re-applies for power restoration, and the verification passes.

[0072] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A substation secondary current circuit intelligent anti-three-error monitoring system, characterized in that, include: The electromagnetic induction monitoring module is installed on the current loop conductors in the terminal boxes, control cabinets and protection panels of the secondary current loop in the substation. It includes an open-type high-precision miniature current transformer for non-contact real-time acquisition of the current value of each loop conductor. A joint status detection module is installed on the test terminal joint of the current loop. It includes a miniature position sensor, which is fixed on the joint base. When the joint is in the insertion position, it outputs a first level signal, and when the joint is in the withdrawal position, it outputs a second level signal. The three-error analysis and judgment module is connected to the electromagnetic induction monitoring module and the continuous state detection module respectively, and performs three-error analysis: The accidental contact judgment is based on the system operating conditions and work ticket information to build a desired current model. The real-time current value is compared with the desired current value. When the current deviation exceeds the preset threshold and the duration exceeds the preset duration, it is judged as an accidental contact event. The system detects incorrect connections by constructing the current circuit topology matrix based on the connected and unconnected status of the circuit, comparing it with the authorized configuration topology matrix, and determining that a misconnection event occurs when there is a discrepancy. The system for determining incorrect settings involves reading the protection device's setting parameters through the communication interface and comparing them with the authorized setting values. If the deviation exceeds the allowable range, it is determined to be an incorrect setting event. The logic interlocking module is connected to the three-error analysis and judgment module and the substation five-prevention system. When the three-error event is detected, it sends an interlocking command to the five-prevention system. The pre-power-on verification module is connected to the electromagnetic induction monitoring module and the interconnection status detection module. Before the power-on operation, it automatically traverses all monitoring nodes to verify that all interconnections of each circuit are in the working state and that there are no open circuits in the current circuit.

2. The intelligent anti-malfunction monitoring system for substation secondary current circuits according to claim 1, characterized in that, The electromagnetic induction monitoring module also includes: The signal conditioning circuit is connected to the open-type high-precision miniature current transformer and is used to amplify and filter the acquired current signal to remove DC and harmonic components. An analog-to-digital converter, connected to the signal conditioning circuit, is used to convert analog signals into digital signals; A communication interface, connected to the analog-to-digital converter, is used to upload digitized current data to the three-error analysis and judgment module.

3. The intelligent anti-malfunction monitoring system for substation secondary current circuits according to claim 1, characterized in that, The continuous strip status detection module also includes: Hall effect sensors, placed near the rotating shaft of the continuous sheet, are used to detect changes in the mechanical position of the continuous sheet. The status coding circuit is connected to the Hall sensor, assigns a unique address code to each connected piece, and uploads the connection status of the connected piece to the address code to the error analysis and judgment module.

4. The intelligent anti-malfunction monitoring system for substation secondary current circuits according to claim 1, characterized in that, In the accidental contact detection, the method for constructing the expected current model is as follows: Based on the current system operation mode, obtain the primary load current and calculate the expected secondary current value Ie by combining the current transformer ratio; The current deviation is determined by the condition that |Ia-Ie|>k×Ie and lasts for a time t0, where Ia is the real-time current value, k is the deviation coefficient with a value range of 0.1~0.3, and t0 is the duration threshold with a value range of 50ms~200ms.

5. The intelligent anti-malfunction monitoring system for substation secondary current circuits according to claim 1, characterized in that, In the misconnection detection, the method for constructing the current loop topology matrix is ​​as follows: The status of each monitoring node's continuous deployment and withdrawal is encoded into binary values, with deployment being 1 and withdrawal being 0, forming a status vector S; Based on the pre-stored loop connection table, the state vector S is mapped to the topology matrix T, where the element Tij represents the connection state between node i and node j. The authorized configuration topology matrix is ​​the standard topology matrix corresponding to the current work ticket.

6. The intelligent anti-malfunction monitoring system for substation secondary current circuits according to claim 1, characterized in that, The logic interlocking module is linked with the five-prevention system through two methods: hard contact output and communication message; When a triple fault event is detected, the logic interlocking module simultaneously outputs a hard contact interlocking signal to the operation circuit of the relevant equipment, and sends the interlocking reason and location information to the backend of the five-prevention system via communication messages.

7. The intelligent anti-malfunction monitoring system for substation secondary current circuits according to claim 1, characterized in that, The verification process of the pre-power-on verification module is as follows: Upon receiving the power supply operation command, a status query command is sent to all connected status detection modules; Collect the status information of all connected areas within a preset time to verify whether they are all in the operational state; Simultaneously, the current data of the electromagnetic induction monitoring module is read to verify whether there is an open circuit. If all verifications pass, a verification pass signal is output, allowing power-on operation; if an abnormality is found, an alarm message is output and power-on operation is blocked.

8. The intelligent anti-malfunction monitoring system for substation secondary current circuits according to claim 1, characterized in that, It also includes a self-diagnostic module for: The electromagnetic induction monitoring module is periodically checked for operation, and an alarm is issued when a sensor disconnection or abnormal signal is detected. Monitor the communication status of the continuous area status detection module and issue an alarm when the communication is interrupted for more than a preset time; Record all alarms and event information to form an operation log.

9. A method for intelligent monitoring of secondary current circuits in substations to prevent three types of errors, characterized in that: Includes the following steps: S1: Install electromagnetic induction monitoring modules on the current loop conductors at the terminal boxes, control cabinets and protection panels of the secondary current loop in the substation, and install a connection status detection module on the test terminal connection of the current loop. S2: The electromagnetic induction monitoring module collects the current value of each circuit conductor in real time through an open-type high-precision miniature current transformer in a non-contact manner. The joint status detection module detects the connection status of each joint in real time through a miniature position sensor and uploads the current value and joint connection status data to the three error analysis and judgment module. S3: The error analysis and judgment module performs error analysis: Accidental contact judgment: Construct a desired current model based on the current system operating conditions and work order information, compare the real-time current value with the desired current value, and determine an accidental contact event when the current deviation exceeds a preset threshold and the duration exceeds a preset duration; Misconnection detection: Construct the current circuit topology matrix based on the connected circuit activation / deactivation status, compare it with the authorized configuration topology matrix, and determine the misconnection event when they are inconsistent; Error setting judgment: The protection device setting parameters are read through the communication interface and compared with the authorized setting values. When the deviation exceeds the allowable range, it is judged as an error setting event. S4: When a three-error event is detected, the logic interlocking module sends an interlocking command to the five-prevention system through hard contact output and communication messages to prevent dangerous operation of the relevant equipment; S5: Before the power-on operation, the pre-power-on verification module automatically traverses all monitoring nodes to verify that all circuit connections are in the working state and that there are no open circuits in the current circuit, and generates a verification report.

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