A current loop monitoring device based on acquisition parameter difference comparison method

Abstract

The present invention relates to a current loop monitoring device based on a method of comparing differences in acquired parameters, and belongs to the technical field of current loop monitoring. The device includes an acquisition module, an analysis and control module, a multi-point grounding alarm module, a display and input module, a dot matrix division module, a non-contact infrared temperature measurement sensor, an audio-visual alarm module, and other structures. The device of the present invention accurately identifies the abnormal situation of multi-point grounding in the current secondary circuit based on the characteristic differences in the current phase and amplitude on the N circuit and the grounding circuit when the secondary current circuit is operating normally and when multi-point grounding occurs; it uses partitioned infrared temperature measurement technology to monitor the temperature of the current terminal in real time, and identifies the abnormal situation of the current loop being disconnected through temperature discrimination; the present invention can flexibly configure monitoring parameters according to the characteristics of different power systems, adapt to a variety of working environments, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of current loop monitoring, and in particular relates to a current loop monitoring device based on an acquisition parameter difference comparison method. Background Art

[0002] The secondary current of the substation is used for protection, measurement, control, and metering devices within the station. The accuracy and reliability of its sampling are very important, especially the current used by the protection device, which is a necessary physical quantity for the implementation of various protection principles and logic within the protection device. To ensure the normal operation of the current loop, it is stipulated that the loop has one and only one grounding point. If the loop has grounding points other than this grounding point, such as artificial grounding or circuit insulation damage, it will cause the protection device to malfunction or refuse to operate. A break in the secondary current circuit is also called an open circuit. When the secondary current circuit is open, a very high voltage will be induced at the secondary open circuit, causing the current terminal to heat up and burn. Real-time monitoring of the secondary current circuit will effectively solve the problem of malfunction and refusal to operate of the protection device, and can also prevent personnel and equipment safety issues caused by circuit problems.

[0003] At present, there is no mature, systematic and effective monitoring principle and technical means for the two major factors of circuit abnormality (broken wires and multi-point grounding). The conventional approach is as follows:

[0004] 1. The protection device uses its CT disconnection detection logic to monitor circuit disconnections. Because the protection device can only monitor disconnections for the current group it is designed for, it cannot effectively monitor disconnections in other windings. Currently, most protection devices respond to CT disconnections with an alarm signal, such as a device abnormality. After receiving this signal, maintenance personnel still need to conduct an on-site inspection to determine the disconnection status, resulting in a time lag between the maintenance personnel's prediction of the cause of the abnormality.

[0005] 2. Daily inspections and scheduled inspections. Operations and maintenance personnel will conduct scheduled temperature measurements on the circuit terminals. Due to the large number of sites and equipment within them, temperature measurements are performed intermittently and periodically, which cannot guarantee real-time and full coverage. Regular inspections are conducted at longer intervals, and circuit anomalies caused by these inspections cannot be avoided.

[0006] 3. Maintenance personnel use clamp meters to determine the presence of multiple grounding points in the current loop based on experience. This situation often occurs when operation and maintenance personnel discover that the three-phase current of the protection device is unbalanced or there is a zero-sequence current, and they inform the maintenance personnel to go to the site for inspection and analysis. There is a probability that such a problem will be discovered, because as long as the protection device does not alarm, the imbalance of the three-phase current of the device or the presence of zero-sequence current may not be discovered. When the load current is not large or the primary equipment is not at fault, the current imbalance caused by multiple grounding points in the secondary current loop is not enough to cause the device to alarm. Moreover, the on-site inspection of the maintenance personnel generally draws the conclusion of multiple grounding points by comparing the currents in the three phases and N circuits of the secondary current, and has never come up with an effective and practical method.

[0007] Therefore, how to overcome the shortcomings of the existing technology is an urgent problem to be solved in the technical field of current loop monitoring devices based on the acquisition parameter difference comparison method. Summary of the Invention

[0008] The purpose of the present invention is to solve the deficiencies of the prior art and to provide a current loop monitoring device based on a collection parameter difference comparison method.

[0009] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A current loop monitoring device based on a collection parameter difference comparison method, comprising:

[0011] The acquisition module is used to collect the current I of the N circuit of the current secondary circuit to be detected. N and the ground loop current I J ;

[0012] The analysis control module is connected to the acquisition module and is used to analyze the current I of the N circuit collected by the acquisition module. N and the ground loop current I J , perform logical judgment and difference judgment to determine whether multiple grounding occurs;

[0013] The multi-point grounding alarm module is connected to the analysis and control module. When the analysis and control module determines that a multi-point grounding occurs, the analysis and control module controls the multi-point grounding alarm module to sound an alarm.

[0014] The display and input module is connected to the analysis and control module and is used to display whether the secondary current circuit to be detected has multiple grounding points;

[0015] The dot matrix division module is used to divide the monitoring panel to be tested into multiple square dot matrices. When dividing, it is necessary to ensure that each terminal on the monitoring panel is only within one square.

[0016] The non-contact infrared temperature sensor is connected to the dot matrix division module and the analysis and control module respectively, and is used to collect the temperature of each square divided by the dot matrix division module, thereby obtaining the temperature of each terminal; and then transmits the temperature value to the analysis and control module;

[0017] The display and input module is also used for users to set temperature thresholds;

[0018] The analysis and control module is used to compare the temperature of each terminal with the temperature threshold, and determine whether the temperature value of each terminal exceeds the temperature threshold. If it exceeds the temperature threshold, it is considered that there is a disconnection, and then the sound and light alarm module is controlled to sound and light alarm;

[0019] The sound and light alarm module is used to sound and light alarm when the temperature value of the terminal exceeds the temperature threshold.

[0020] Furthermore, preferably, the acquisition module is a current transformer.

[0021] Furthermore, preferably, the specific method of logical judgment is:

[0022] Set the multi-point ground current threshold I qd , only when the collected I N and I J Both greater than I qd , triggers the difference judgment.

[0023] Furthermore, preferably, the specific method of difference determination is:

[0024] Calculate the absolute value of the sum of the N-loop and ground loop currents and compare it with the set error current value. If it is less than the error current value, it is considered that there is a multi-point grounding anomaly and the multi-point grounding alarm module is triggered to alarm; otherwise, it is recorded as a normal operating state.

[0025] Furthermore, preferably, the error current ΔI is set to three cases, and the specific calculation formula is as follows:

[0026]

[0027] Further, preferably, the temperature threshold includes an upper temperature limit and a lower temperature limit.

[0028] Furthermore, preferably, when the temperature value of the connection terminal is greater than the upper temperature limit, or less than the lower temperature limit, an audible and visual alarm is performed.

[0029] Furthermore, preferably, a dynamic adjustment module is further included, which is connected to the analysis and control module and is used to dynamically adjust the temperature threshold according to different working environment temperatures.

[0030] Furthermore, preferably, the display and input module is further configured to display a judgment result obtained by the analysis and control module as to whether the temperature value of each terminal exceeds a temperature threshold.

[0031] Furthermore, preferably, the display and input module is also used to set a multi-point grounding current threshold value and an error current value.

[0032] The acquisition module of the present invention uses a high-precision CT (current transformer) to collect the loop current through cable extraction.

[0033] The dynamic adjustment module of the present invention can be configured to implement dynamic temperature threshold adjustment according to different working environment temperatures to adapt to changes in the working environment, improve monitoring reliability, and avoid false alarms.

[0034] The present invention has the following specific features:

[0035] ① Clear alarm information for abnormal current loops: This invention accurately identifies abnormal conditions with multiple grounding in the secondary current loop based on the characteristic differences in current phase and amplitude between normal operation of the secondary current loop and that of the N loop and ground loop when multiple grounding occurs. It also uses zoned infrared temperature measurement technology to monitor the temperature of the current terminals in real time, and identifies abnormal conditions with current loop disconnections through temperature discrimination. The alarm information issued by this invention is a clear signal of multiple grounding and loop disconnection.

[0036] ② Real-time monitoring of circuit operation: Provides an effective monitoring method for abnormal situations such as multiple grounding points and circuit disconnection in the secondary circuit of the current transformer, which can issue an alarm when a fault occurs, helping maintenance personnel take timely measures to avoid the expansion of system and equipment faults;

[0037] ③ Reduce the risk of false operation and refusal to operate: By promptly handling circuit abnormalities after they are discovered, the phenomenon of false operation and refusal to operate caused by current circuit abnormalities can be reduced, thereby improving the reliability of protection devices and ensuring the safe and stable operation of the power system;

[0038] ④ Improve operation and maintenance efficiency: Realize automated monitoring of current circuits, reduce the workload of manual inspections, improve equipment maintenance efficiency, and enable operation and maintenance personnel to manage and maintain the power system more effectively.

[0039] The present invention integrates current and temperature acquisition, simplifying the detection and access process. At the same time, the design takes into account the independence of normal operation and abnormality monitoring functions to ensure that the normal operation of the current loop is not affected.

[0040] The present invention uses a collection parameter difference comparison method to analyze current and temperature signals, thereby accurately identifying abnormal conditions such as multiple grounding points and disconnection in the current secondary circuit.

[0041] The present invention can simultaneously access and monitor multiple windings, has an independent abnormality judgment function, and provides status monitoring of multiple windings through alarm output.

[0042] The present invention divides the monitoring area into a grid matrix for detailed temperature mapping and anomaly location, which improves monitoring accuracy and fault detection capabilities.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) Accurate fault identification: By acquiring current signal information in real time, it can quickly identify abnormal conditions in the current loop, including multi-point grounding and cable damage, significantly improving the accuracy and timeliness of fault detection.

[0045] (2) Real-time monitoring and early warning: The present invention can realize continuous monitoring of the current loop and issue fault early warning information in a timely manner. Operation and maintenance personnel can be reminded in time at the early stage of the problem to avoid accidents.

[0046] (3) Improving protection reliability: The device of the present invention is based on the collection quantity difference comparison method, which can effectively reduce the false operation and refusal of protection equipment, ensure that the protection device can operate accurately when a real fault occurs, thereby improving the overall reliability and safety of the power system.

[0047] (4) Information integration and analysis: The device of the present invention can be integrated with the power dispatching and management system to realize the centralized management and analysis of monitoring data, provide a basis for decision-making, and optimize the operation and maintenance strategy of the power system.

[0048] (5) Reduced Operation and Maintenance Costs: This invention reduces human resource input and operation and maintenance costs through automated monitoring, thereby improving the economic benefits of the power system. Furthermore, the ability to detect problems early will extend the life of the equipment, thereby reducing the frequency of replacement and repair.

[0049] (6) Highly adaptable monitoring scheme: The present invention can flexibly configure monitoring parameters according to the characteristics of different power systems, adapt to various working environments, and has wide application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is the normal operation schematic diagram;

[0051] Figure 2 This is the phase line grounding principle diagram;

[0052] Figure 3 This is the N circuit grounding schematic diagram;

[0053] Figure 4 This is the schematic diagram of the phase line and N loop grounding at the same time;

[0054] Figures 1 to 4 In the figure, A, B, C, and N represent the three-phase circuits ABC and N of the secondary current transformer, respectively; J represents the ground circuit; I A , I B , I C , I N The corresponding current transformers are the secondary ABC three-phase current and the N loop current, I J represents the ground loop current; V is the potential difference between the two grounding points, I l It is the circulating current caused by the potential difference between the two grounding points; P represents the secondary system device; I A1 , I A2 They represent the shunt current when the phase A loop is grounded; I A21 , I A22 Indicates that when the A and N phase circuits are grounded at the same time, I A2 Shunt current when flowing back through the N loop; I A23 , I A24 Represents the case where the A and N phase circuits are grounded at the same time. A2 Shunt current when flowing back through the ground;

[0055] Figure 5 This is the logic block diagram of multi-point grounding;

[0056] Figure 6 A schematic structural diagram of a current loop monitoring device based on a collection parameter difference comparison method according to the present invention;

[0057] Figure 7 This is another structural diagram of the current loop monitoring device based on the acquisition parameter difference comparison method of the present invention. DETAILED DESCRIPTION

[0058] The present invention is described in further detail below with reference to the embodiments.

[0059] Those skilled in the art will understand that the following examples are intended to illustrate the present invention only and should not be construed as limiting the scope of the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in the art or in the product specifications were used. Materials or equipment used without manufacturer identification are commercially available conventional products.

[0060] Example 1

[0061] like Figure 6 As shown, a current loop monitoring device based on the acquisition parameter difference comparison method includes:

[0062] The acquisition module 101 is used to acquire the current I of the N-loop of the current secondary loop to be detected. N and the ground loop current I J;

[0063] The analysis control module 102 is connected to the acquisition module 101 and is used to analyze the current I of the N circuit collected by the acquisition module 101. N and the ground loop current I J , perform logical judgment and difference judgment to determine whether multiple grounding occurs;

[0064] The multi-point grounding alarm module 103 is connected to the analysis and control module 102. When the analysis and control module 102 determines that a multi-point grounding occurs, the analysis and control module 102 controls the multi-point grounding alarm module 103 to issue an alarm.

[0065] The display and input module 104 is connected to the analysis and control module 102 and is used to display whether the secondary current circuit to be detected has multiple grounding points;

[0066] The dot matrix division module 106 is used to divide the monitoring panel to be inspected into a plurality of square dot matrices; when dividing, it is necessary to ensure that each terminal on the monitoring panel is within only one square;

[0067] The non-contact infrared temperature sensor 105 is connected to the dot matrix division module 106 and the analysis and control module 102, and is used to collect the temperature of each square divided by the dot matrix division module 106, thereby obtaining the temperature of each terminal; and then transmits the temperature value to the analysis and control module 102;

[0068] The display and input module 104 is also used for the user to set the temperature threshold;

[0069] The analysis control module 102 is used to compare the temperature of each terminal with the temperature threshold, and determine whether the temperature value of each terminal exceeds the temperature threshold. If it exceeds, it is considered that there is a disconnection, and then the sound and light alarm module 107 is controlled to sound and light alarm;

[0070] The sound and light alarm module 107 is used to generate a sound and light alarm when the temperature value of the connection terminal exceeds a temperature threshold.

[0071] Example 2

[0072] like Figure 6 As shown, a current loop monitoring device based on the acquisition parameter difference comparison method includes:

[0073] The acquisition module 101 is used to acquire the current I of the N-loop of the current secondary loop to be detected. N and the ground loop current I J ;

[0074] The analysis control module 102 is connected to the acquisition module 101 and is used to analyze the current I of the N circuit collected by the acquisition module 101.N and the ground loop current I J , perform logical judgment and difference judgment to determine whether multiple grounding occurs;

[0075] The multi-point grounding alarm module 103 is connected to the analysis and control module 102. When the analysis and control module 102 determines that a multi-point grounding occurs, the analysis and control module 102 controls the multi-point grounding alarm module 103 to issue an alarm.

[0076] The display and input module 104 is connected to the analysis and control module 102 and is used to display whether the secondary current circuit to be detected has multiple grounding points;

[0077] The dot matrix division module 106 is used to divide the monitoring panel to be inspected into a plurality of square dot matrices; when dividing, it is necessary to ensure that each terminal on the monitoring panel is within only one square;

[0078] The non-contact infrared temperature sensor 105 is connected to the dot matrix division module 106 and the analysis and control module 102, and is used to collect the temperature of each square divided by the dot matrix division module 106, thereby obtaining the temperature of each terminal; and then transmits the temperature value to the analysis and control module 102;

[0079] The display and input module 104 is also used for the user to set the temperature threshold;

[0080] The analysis control module 102 is used to compare the temperature of each terminal with the temperature threshold, and determine whether the temperature value of each terminal exceeds the temperature threshold. If it exceeds, it is considered that there is a disconnection, and then the sound and light alarm module 107 is controlled to sound and light alarm;

[0081] The sound and light alarm module 107 is used to generate a sound and light alarm when the temperature value of the connection terminal exceeds a temperature threshold.

[0082] The acquisition module 101 is a current transformer.

[0083] The specific method of logical judgment is:

[0084] Set the multi-point ground current threshold I qd , only when the collected I N and I J Both greater than I qd , triggers the difference judgment.

[0085] The specific method of difference judgment is:

[0086] The absolute value of the sum of the N-loop and ground loop currents is calculated and compared with the set error current value. If it is less than the error current value, it is considered that there is a multi-point grounding anomaly, and the multi-point grounding alarm module 103 is triggered to alarm; otherwise, it is recorded as a normal operating state.

[0087] There are three settings for the error current ΔI. The specific calculation formula is as follows:

[0088]

[0089] The temperature threshold includes an upper temperature limit and a lower temperature limit.

[0090] When the temperature value of the terminal is greater than the upper temperature limit or less than the lower temperature limit, an audible and visual alarm will be triggered.

[0091] Example 3

[0092] like Figure 7 As shown, a current loop monitoring device based on the acquisition parameter difference comparison method includes:

[0093] The acquisition module 101 is used to acquire the current I of the N-loop of the current secondary loop to be detected. N and the ground loop current I J ;

[0094] The analysis control module 102 is connected to the acquisition module 101 and is used to analyze the current I of the N circuit collected by the acquisition module 101. N and the ground loop current I J , perform logical judgment and difference judgment to determine whether multiple grounding occurs;

[0095] The multi-point grounding alarm module 103 is connected to the analysis and control module 102. When the analysis and control module 102 determines that a multi-point grounding occurs, the analysis and control module 102 controls the multi-point grounding alarm module 103 to issue an alarm.

[0096] The display and input module 104 is connected to the analysis and control module 102 and is used to display whether the secondary current circuit to be detected has multiple grounding points;

[0097] The dot matrix division module 106 is used to divide the monitoring panel to be inspected into a plurality of square dot matrices; when dividing, it is necessary to ensure that each terminal on the monitoring panel is within only one square;

[0098] The non-contact infrared temperature sensor 105 is connected to the dot matrix division module 106 and the analysis and control module 102, and is used to collect the temperature of each square divided by the dot matrix division module 106, thereby obtaining the temperature of each terminal; and then transmits the temperature value to the analysis and control module 102;

[0099] The display and input module 104 is also used for the user to set the temperature threshold;

[0100] The analysis control module 102 is used to compare the temperature of each terminal with the temperature threshold, and determine whether the temperature value of each terminal exceeds the temperature threshold. If it exceeds, it is considered that there is a disconnection, and then the sound and light alarm module 107 is controlled to sound and light alarm;

[0101] The sound and light alarm module 107 is used to generate a sound and light alarm when the temperature value of the connection terminal exceeds a temperature threshold.

[0102] The acquisition module 101 is a current transformer.

[0103] The specific method of logical judgment is:

[0104] Set the multi-point ground current threshold I qd , only when the collected I N and I J Both greater than I qd , triggers the difference judgment.

[0105] The specific method of difference judgment is:

[0106] The absolute value of the sum of the N-loop and ground loop currents is calculated and compared with the set error current value. If it is less than the error current value, it is considered that there is a multi-point grounding anomaly, and the multi-point grounding alarm module 103 is triggered to alarm; otherwise, it is recorded as a normal operating state.

[0107] There are three settings for the error current ΔI. The specific calculation formula is as follows:

[0108]

[0109] The temperature threshold includes an upper temperature limit and a lower temperature limit.

[0110] When the temperature value of the terminal is greater than the upper temperature limit or less than the lower temperature limit, an audible and visual alarm will be triggered.

[0111] The system further includes a dynamic adjustment module 108 , which is connected to the analysis and control module 102 and is configured to dynamically adjust the temperature threshold according to different working environment temperatures.

[0112] The display and input module 104 is further configured to display the determination result obtained by the analysis and control module 102 as to whether the temperature value of each terminal exceeds a temperature threshold.

[0113] The display and input module 104 is further used to set a multi-point ground current threshold value and an error current value.

[0114] Example 4

[0115] The present invention develops a device that can be implemented and effectively monitor the secondary current circuit - a current circuit monitoring device based on the acquisition parameter difference comparison method, which can issue an alarm when a circuit abnormality is detected. The device of the present invention targets the characteristics revealed by the two common abnormal conditions of the secondary current circuit (multiple-point grounding and circuit disconnection), and uses the characteristic differences as the basis for diagnosing the abnormality. When multiple-point grounding and circuit disconnection occur in the circuit, the signal acquisition is completed by acquisition modules based on different principles. The collected physical quantities are finally handed over to the host processor for judgment. The judged abnormality will be displayed on the display of the device and transmitted to the measurement and control device in the form of electrical signals to complete the alarm.

[0116] 1. Multi-point grounding:

[0117] 1. Methods and principles

[0118] Based on Kirchhoff's current law (also known as the node current law, which states that the sum of the currents flowing into any node in a circuit at any time is equal to zero), this paper analyzes the currents in the secondary N-loop and grounding loop of a current transformer, and derives the characteristic differences between the loop under multi-point grounding and normal operation. This is used to identify multi-point grounding. The analysis method and conclusions are as follows:

[0119] ①Normal operation

[0120] The normal operating principle diagram is as follows Figure 1 As shown;

[0121] I J =0;

[0122] I N =I A +I B +I C =0;

[0123] This shows that when the current secondary circuit is operating normally, the current in the N circuit and the ground circuit is zero.

[0124] ②Phase line grounding

[0125] Phase line grounding principle diagram Figure 2 shown.

[0126] ∵I N =I A1 +I B +I C =-I A2 ,I J =I A2

[0127] ∴I N +I J =0

[0128] When the phase line is grounded, there is a certain amount of current in the N circuit and the ground circuit, and the sum of the two is zero.

[0129] ③N circuit is grounded

[0130] The schematic diagram of the grounding of the N circuit is as follows Figure 3 shown.

[0131] ∵I N =-I l ,I J =I l

[0132] ∴I N +I J =0

[0133] When the N line loop is grounded, the focus is on the circulating current formed by the potential difference between the two grounding points. There are currents of a certain magnitude in the N loop and the ground loop, and the sum of the two is zero.

[0134] ④The phase line and N circuit are grounded at the same time

[0135] The principle diagram of phase line and N circuit grounding at the same time is as follows Figure 4 shown.

[0136] ∵I N =-I A21 +I A23 ,I J =-I A22 +I A24 -I A2 =-I A21 +(-I A22 ),I A2 =I A23 +I A24

[0137] ∴I N +I J =-I A21 +(-I A22 )+I A23 +I A24

[0138] =-I A2 +I A2 =0

[0139] When both the phase line and the neutral loop are grounded, the circulating current caused by the neutral loop grounding is the same as in Case 3, and its result does not affect the conclusion. Focusing on the current flow in the grounded phase when both the phase line and the neutral loop are grounded, the conclusion remains that a certain amount of current flows in the neutral loop and the ground loop, and the sum of the two is zero.

[0140] The general conclusion is: when the current secondary circuit operates normally, the current in the N circuit and the grounding circuit is zero; when multiple point grounding occurs, there is a certain amount of current in the N circuit and the grounding circuit, and the sum of the two is zero.

[0141] 2. Signal acquisition

[0142] The real-time current collection is completed by the acquisition module, which uses a high-precision current transformer to collect the current of the current transformer secondary N loop and the ground loop. The acquisition module can simultaneously access multiple current transformer secondary winding loops, and each winding loop can be connected in sequence corresponding to the actual winding number.

[0143] 3. Logical reasoning

[0144] 1. Current threshold judgment: First, determine whether the current of the N loop and the ground loop exceeds the set multi-point grounding current threshold. If both exceed, the multi-point grounding judgment logic is entered.

[0145] 2. Current difference calculation: Calculate the absolute value of the sum of the N loop and ground loop currents and compare it with the set error current value.

[0146] 3. Alarm triggering: If the absolute value of the sum is less than the error current value, it is considered that there is a multi-point grounding anomaly and the alarm is triggered; otherwise, the normal operation status is recorded.

[0147] 4. Theoretical basis: Kirchhoff's current law shows that the sum of the current flowing into the node should be zero. Therefore, under normal circumstances, the current in the N loop and the ground loop of the current secondary loop should be zero. It can be expressed as:

[0148] ∑I in =0;

[0149] Among them, I in is the current flowing into the node;

[0150] 5. Logical judgment formula: In order to eliminate minor interference in normal operation (such as small current fluctuations caused by capacitive current), set the multi-point grounding current threshold value I qd , only when the collected I N and I J Both greater than I qd When the voltage is 0.001V, the multi-point grounding detection logic (i.e., difference judgment) will be triggered. For example, the initial value is set to 5mA:

[0151] I N >I qd , and I J >I qd ;

[0152] The threshold value can be adjusted based on field experimental data to improve detection accuracy.

[0153] 6. Difference judgment: According to the difference comparison method, the abnormality is judged by calculating the absolute value of the sum of the N loop current and the ground loop current. When the sum of the two meets the following conditions, it is judged that multiple grounding has occurred:

[0154] |I N +I J |>ΔI

[0155] Where ΔI represents the error current value. This value is set based on field experience and test data. For example, the error current range can be set using the following formula.

[0156]

[0157] The logic block diagram of the above logic judgment and difference judgment is as follows Figure 5 shown.

[0158] 7. In actual operation, data collected through experiments show that the multi-point grounding phenomenon will exhibit specific numerical characteristics under different current environments.

[0159] The following is example data:

[0160] Under normal circumstances: the current in the N loop and the ground loop remains at a level close to zero, usually not exceeding a tiny noise fluctuation of 5mA.

[0161] In abnormal situations: When multiple points are grounded, the measured N-loop current and ground current can exceed 5mA, and in some extreme cases, can even reach hundreds of mA. To address this, an adjustable threshold value is designed to ensure accurate abnormality detection in different operating environments. This is illustrated below using 5mA as an example, as shown in Table 1.

[0162] Table 1

[0163] state N loop current (mA) Ground loop current (mA) Whether to enter the fault program Normal operation <5 <5 no Multi-point grounding >5 >5 yes critical cases 5 5 no

[0164] Through multiple experimental verifications, it is shown that this threshold setting can effectively screen out normal fluctuations and real multi-point grounding faults, thereby improving the reliability of judgment.

[0165] First, to ensure the accuracy and stability of the entire monitoring device, we conduct a preliminary assessment of the currents in the N-loop and ground loops to determine whether they exceed a preset threshold. This preset value is typically adjusted based on actual project requirements to ensure sensitivity while minimizing the probability of false alarms. If the current in any loop exceeds this threshold, the device automatically enters the multi-point ground fault detection logic to further analyze the abnormal condition. After confirming that the current exceeds the threshold, the device calculates the absolute value of the sum of the N-loop and ground loop currents. This difference is calculated to the milliampere (mA) level and compared with a preset error current value. This error current value is set to account for the inevitable current fluctuations in the measuring instrument and cable during operation, allowing for a certain degree of deviation to prevent the device from misjudging normal operation. If the absolute value of the sum does not exceed the set error current, the condition is considered a multi-point ground fault and the device immediately triggers the alarm mechanism. Alarm information is recorded in the monitoring log for subsequent analysis. This logical judgment structure, implemented through multi-level analysis modules, not only improves the accuracy of current loop anomaly identification but also significantly enhances the reliability and real-time performance of the monitoring device. By performing real-time calculations and processing on the data from each acquisition module layer by layer, the device eliminates unnecessary interference, enabling more accurate identification of abnormal conditions and preventing false alarms caused by current fluctuations.

[0166] In practical applications, considering current measurement accuracy and potential interference between acquisition modules, the multi-point grounding current threshold is typically set to 5mA (adjustable), and this setting can be further adjusted based on actual collected current data. When the device detects that the average current of the N-loop and ground loop exceeds 5mA, it activates the multi-point grounding alarm module. The error current value is dynamically adjusted in real time based on the collected current. Lower operating currents result in lower braking currents, while higher operating currents result in proportionally higher braking currents. This setting not only prevents misidentification of faults but also improves fault detection sensitivity. Through this layered analysis, the current anomaly discrimination model is continuously optimized to achieve more accurate multi-point grounding fault detection capabilities.

[0167] 4. Response and signal transmission

[0168] The multi-point grounding alarm is transmitted to the substation backstage or remotely via a pair of cables in the form of electrical signals. On the other hand, the device display and input module show which winding circuit has a fault.

[0169] 2. Disconnection

[0170] The present invention uses a non-contact infrared temperature sensor to capture the infrared spectrum radiated by each terminal on the monitoring panel in real time. The detector integrated inside the infrared temperature sensor is based on the infrared energy radiated by the target object. According to the blackbody radiation law, the temperature of the object is proportional to its ability to radiate heat energy. It can emit infrared radiation of a specific wavelength. The higher the temperature, the stronger the radiation intensity. The received radiation intensity is converted into a corresponding temperature value. Compared with traditional contact temperature measurement methods, non-contact technology can effectively avoid measurement errors caused by poor thermal contact between the thermocouple and the object being measured, thereby improving the accuracy and real-time performance of the measurement.

[0171] To further improve the accuracy of temperature monitoring, the present invention utilizes dot matrix partitioning technology, dividing the monitoring panel into multiple, finely detailed grids. Each terminal corresponds to a corresponding grid grid. This high-resolution spatial partitioning ensures localized and detailed temperature data collection. This method not only achieves precise temperature mapping but also precisely locates abnormal temperature distributions, providing richer and more reliable information for subsequent data processing. Each grid not only independently monitors temperature changes within it, but also generates a rich data set across the entire monitoring panel, enabling more accurate temperature mapping. The present invention incorporates a flexible threshold setting function, allowing users to customize temperature monitoring thresholds based on actual application scenarios and device characteristics. On the display and input module, users can conveniently enter specific upper and lower temperature limits, which the device uses as a baseline for real-time monitoring. If the monitored temperature exceeds these set thresholds, the analysis and control module promptly identifies the abnormal condition. This process relies on complex signal processing algorithms that rapidly analyze and compare temperature data from each grid, ensuring efficient and accurate identification of any deviations from the normal operating range. Furthermore, the device of the present invention can also be configured to dynamically adjust the threshold value according to different temperature change rates and fluctuation amplitudes to adapt to changes in the working environment and improve the reliability of monitoring.

[0172] Upon identifying an anomaly, the analysis and control module responds quickly. First, an audible and visual alarm alerts the operator, alerting them to the abnormal equipment status so they can take timely action. This alarm mechanism not only increases the vigilance of on-site operators but also effectively shortens fault response time, thereby reducing the risk of equipment damage and safety hazards.

[0173] Specifically:

[0174] a. The wiring terminals on the monitoring panel radiate infrared spectra, and the non-contact infrared temperature sensor is aimed at the monitoring panel to capture these infrared spectra in real time.

[0175] b. After receiving infrared energy, the detector inside the non-contact infrared temperature sensor converts it into a temperature value according to the blackbody radiation law. The converted temperature value is transmitted to the analysis and control module.

[0176] c. The dot matrix division module divides the monitoring panel into multiple grid dot matrices. Each terminal corresponds to only one grid area, thus realizing localized and detailed collection of temperature data.

[0177] d. The analysis and control module receives temperature data from the non-contact infrared temperature sensor. Users set upper and lower temperature thresholds through the display and input module. The analysis and control module quickly analyzes and compares the temperature data for each grid square to determine whether the temperature exceeds the threshold.

[0178] e. If the temperature exceeds the threshold, the sound and light alarm module is triggered, and the sound and light alarm module is controlled to sound and light alarm to warn the operator.

[0179] The device of the present invention analyzes the characteristics of the two major abnormal conditions of the current secondary circuit, and simultaneously collects the current and temperature physical signals into the device for comparison and analysis, thereby realizing comprehensive and reliable monitoring and alarm of the current secondary circuit.

[0180] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A current loop monitoring device based on acquisition parameter difference comparison method, characterized in that: include: The acquisition module (101) is used to acquire the current I of the N-loop of the current secondary loop to be detected. N and the ground loop current I J ; The analysis control module (102) is connected to the acquisition module (101) and is used to analyze the current I of the N circuit acquired by the acquisition module (101). N and the ground loop current I J , perform logical judgment and difference judgment to determine whether multiple grounding occurs; The multi-point grounding alarm module (103) is connected to the analysis and control module (102). When the analysis and control module (102) determines that a multi-point grounding occurs, the analysis and control module (102) controls the multi-point grounding alarm module (103) to issue an alarm. A display and input module (104), connected to the analysis and control module (102), is used to display whether a multi-point grounding occurs in the current secondary circuit to be detected; A dot matrix division module (106) is used to perform dot matrix division on the monitoring panel to be detected, dividing it into a plurality of square dot matrices; When dividing, you need to ensure that each terminal on the monitoring panel is only in one square; The non-contact infrared temperature sensor (105) is connected to the dot matrix division module (106) and the analysis and control module (102) respectively, and is used to collect the temperature of each square divided by the dot matrix division module (106), thereby obtaining the temperature of each terminal; and then transmitting the temperature value to the analysis and control module (102); The display and input module (104) is also used for the user to set the temperature threshold; The analysis control module (102) is used to compare the temperature of each terminal with a temperature threshold value, and determine whether the temperature value of each terminal exceeds the temperature threshold value. If it exceeds the temperature threshold value, it is considered that there is a disconnection, and then the sound and light alarm module (107) is controlled to sound and light alarm; The sound and light alarm module (107) is used to generate a sound and light alarm when the temperature value of the connection terminal exceeds a temperature threshold; The specific method of logical judgment is: Set the multi-point ground current threshold I qd , only when the collected I N and I J Both greater than I qd When , the difference judgment is triggered; The specific method of difference judgment is: Calculate the absolute value of the sum of the N loop and ground loop currents and compare it with the set error current value. If the absolute value is less than the error current value, it is considered that there is a multi-point grounding anomaly, and the multi-point grounding alarm module (103) is triggered to alarm; otherwise, it is recorded as a normal operating state; There are three settings for the error current ΔI. The specific calculation formula is as follows:

2. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 1, characterized in that: The acquisition module (101) is a current transformer.

3. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 1, characterized in that: The temperature threshold includes an upper temperature limit and a lower temperature limit.

4. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 3, characterized in that: When the temperature value of the terminal is greater than the upper temperature limit or less than the lower temperature limit, an audible and visual alarm will be triggered.

5. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 4, characterized in that: The system further comprises a dynamic adjustment module (108), which is connected to the analysis and control module (102) and is used to dynamically adjust the temperature threshold according to different working environment temperatures.

6. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 1, characterized in that: The display and input module (104) is further used to display the judgment result of whether the temperature value of each connection terminal obtained by the analysis control module (102) exceeds the temperature threshold.

7. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 1, characterized in that: The display and input module (104) is also used to set the multi-point grounding current threshold value and the error current value.

Images