Current loop monitoring device based on acquired parameter difference comparison method

Abstract

The invention relates to a current loop monitoring device based on an acquisition parameter difference comparison method, and belongs to the technical field of current loop monitoring. The device comprises an acquisition module, an analysis 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, a sound-light alarm module and the like. According to the device, the abnormal condition of multi-point grounding of the current secondary circuit is accurately identified according to the characteristic difference of current phases and amplitudes on the N circuit and the grounding circuit when the secondary current circuit is in normal operation and multi-point grounding occurs; the temperature of a current terminal is monitored in real time by adopting a partitioned infrared temperature measurement technology, and the abnormal condition of disconnection of a current loop is identified through temperature discrimination; the system can flexibly configure monitoring parameters according to the characteristics of different power systems, is suitable for various working environments, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of current loop monitoring, and in particular relates to a current loop monitoring device based on a collection 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 correctness and reliability of its sampling are very important, especially the current used by the protection device, which is a necessary physical quantity based on which the protection principles and logic implementations in the protection device are based. In order to ensure the normal operation of the current loop, it is stipulated that the loop has one and only one grounding point. If there are other grounding points caused by other reasons besides this grounding point, such as artificial grounding and circuit insulation damage, it will cause the protection device to malfunction or refuse to operate. The secondary current circuit is broken, 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 of the protection device, and can also prevent personnel and equipment safety problems 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 abnormal circuit (broken wire and multi-point grounding). The conventional practices are as follows:

[0004] 1. Use the CT disconnection judgment logic of the protection device to monitor the circuit disconnection. Since the protection device can only monitor the disconnection of the current group it uses, it cannot effectively monitor when other windings are disconnected. At present, most protection devices send out alarm signals such as device abnormalities in response to CT disconnection. After receiving the signal, the operation and maintenance personnel still need to go to the site for inspection to know the disconnection result. There is a time difference in the middle and the maintenance personnel's expectation of the cause of the device abnormality.

[0005] 2. Daily inspections and scheduled inspections. The operation and maintenance personnel will carry out planned temperature measurement work on the circuit terminals. Due to the large number of sites and equipment in the stations, the temperature measurement work is carried out intermittently and periodically, and real-time and full coverage cannot be guaranteed. The time interval for scheduled inspections is longer, and it cannot avoid circuit abnormalities caused by this scheduled inspection work.

[0006] 3. Maintenance personnel use clamp meters to determine the situation of multiple grounding points in the current loop based on experience. This situation often occurs when the operation and maintenance personnel find 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 three-phase current imbalance or the existence of zero-sequence current in the device may not be discovered, and when the load current is not large or the primary equipment is not faulty, 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-phase 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 prior art 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 purpose, 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 point 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] A display and input module, connected to the analysis and control module, is used to display whether the current secondary 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 in 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, so as to obtain the temperature of each terminal; and then transmit 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 control module is used to compare the temperature of each wiring terminal with the temperature threshold value, and determine whether the temperature value of each wiring 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 is controlled to sound and light alarm;

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

[0020] Further, 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 judgment is:

[0024] Calculate the absolute value of the sum of the currents of the N loop and the ground loop, 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, triggering the multi-point grounding alarm module to alarm; otherwise, it is recorded as a normal operating state.

[0025] Further, preferably, the error current ΔI is set to three conditions, 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] Further, 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] Further, preferably, the display and input module is also used to display the judgment result of whether the temperature value of each terminal obtained by the analysis control module exceeds the temperature threshold.

[0031] Further, 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 lead-out.

[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 the reliability of monitoring, and avoid false alarms.

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

[0035] ① Clearly identify abnormal alarm information of current loop: The present invention accurately identifies abnormal situations of multi-point grounding in the current secondary loop based on the characteristic differences of the current phase and amplitude on the N loop and the ground loop when the secondary current loop is operating normally and when multi-point grounding occurs; the partitioned infrared temperature measurement technology is used to monitor the temperature of the current terminal in real time, and the abnormal situation of disconnection in the current loop is identified by temperature discrimination; the alarm information issued by the present invention is a clear signal of multi-point grounding and loop disconnection;

[0036] ② Real-time monitoring of circuit operation: Provides an effective monitoring method for abnormal situations such as multi-point grounding and circuit disconnection in the secondary circuit of the current transformer, which can issue an alarm when a fault occurs, helping maintenance personnel to 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 abnormal circuit conditions after discovery, the phenomenon of false operation and refusal to operate caused by abnormal current circuits 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 automatic monitoring of current circuits, reduce the workload of manual inspections, improve the efficiency of equipment maintenance, and enable operation and maintenance personnel to manage and maintain the power system more effectively.

[0039] The present invention integrates current acquisition and temperature acquisition, simplifies the detection and access process. At the same time, the design takes into account the independence of normal operation and abnormal 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 multi-point grounding and disconnection of 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 abnormality 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 is possible to quickly identify abnormal conditions in the current loop, including multi-point grounding, cable damage, etc., 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) Reduce operation and maintenance costs: The present invention reduces human resource investment and operation and maintenance costs through automated monitoring methods, thereby improving the economic benefits of the power system. At the same time, the ability to detect problems early will extend the service 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 schematic diagram of grounding of N loop;

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

[0054] Figure 1 to Figure 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 grounding circuit; I A ,I B ,I C ,I N The corresponding current transformer secondary ABC three-phase current and 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 two grounding points; P represents the secondary system device; I A1 ,I A2 They represent the shunt current when the A phase 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 when the A and N phase circuits are grounded at the same time. A2 Shunt current when flowing back through the ground;

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

[0056] Figure 6 It is a structural schematic diagram of a current loop monitoring device based on the acquisition parameter difference comparison method of the present invention;

[0057] Figure 7 It is another structural schematic 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 further described in detail below in conjunction with embodiments.

[0059] Those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product specifications are used. If the manufacturer of the materials or equipment used is not specified, they are all conventional products that can be purchased.

[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 circuit of the current secondary circuit 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 point 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 sound 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 current secondary circuit to be detected has multiple grounding points;

[0066] The dot matrix division module 106 is used to divide the monitoring panel to be detected 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 respectively, and is used to collect the temperature of each square divided by the dot matrix division module 106, so as to obtain the temperature of each terminal; and then transmit 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 circuit of the current secondary circuit 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 point 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 sound 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 current secondary circuit to be detected has multiple grounding points;

[0077] The dot matrix division module 106 is used to divide the monitoring panel to be detected 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 respectively, and is used to collect the temperature of each square divided by the dot matrix division module 106, so as to obtain the temperature of each terminal; and then transmit 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 currents of the N loop and the ground loop 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, triggering the multi-point grounding alarm module 103 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 given.

[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 circuit of the current secondary circuit 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 point 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 sound 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 current secondary circuit to be detected has multiple grounding points;

[0097] The dot matrix division module 106 is used to divide the monitoring panel to be detected 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 respectively, and is used to collect the temperature of each square divided by the dot matrix division module 106, so as to obtain the temperature of each terminal; and then transmit 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 currents of the N loop and the ground loop 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, triggering the multi-point grounding alarm module 103 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 given.

[0111] The system further includes 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.

[0112] The display and input module 104 is also used to display the judgment result of whether the temperature value of each terminal obtained by the analysis control module 102 exceeds the temperature threshold.

[0113] The display and input module 104 is also used to set the multi-point grounding current threshold value and the error current value.

[0114] Example 4

[0115] The present invention develops a device that can implement 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 uses the characteristic differences as the basis for diagnosing the abnormality in view of the characteristics revealed by the two common abnormal conditions of the secondary current circuit (multiple-point grounding and circuit disconnection). When multiple-point grounding and circuit disconnection occur in the circuit, 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 abnormal conditions 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] The present invention analyzes the current of the secondary N loop and the grounding loop of the current transformer according to Kirchhoff's current law (Kirchhoff's current law is also called the node current law, which states that the sum of the currents flowing into any node in the circuit at any time is equal to zero.), and obtains the characteristic difference between the multi-point grounding and normal operation of the loop, which is used to distinguish multi-point grounding. The analysis method and conclusion are as follows:

[0119] ①Normal operation

[0120] The normal operation schematic 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 loop current formed by the potential difference between the two grounding points is considered. There is a certain amount of current in the N loop and the grounding loop, and the sum of the two is zero.

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

[0135] The schematic diagram of the 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 the phase line and N loop are grounded at the same time, the circulating current caused by the grounding of the N loop is the same as in case ③, and its result will not affect the conclusion. Focusing on the analysis of the current flow direction on the grounded phase when the phase line and N loop are grounded at the same time, the conclusion is still that there is a certain amount of current in the N loop and the grounding 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 collection module, which uses a high-precision current transformer to collect the current of the current transformer secondary N loop and the ground loop. The collection 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, judge whether the current of the N loop and the ground loop exceeds the set multi-point grounding current threshold. If both exceed, enter the multi-point grounding judgment logic.

[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 an alarm is triggered; otherwise, the normal operating 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, so 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 under 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 The multi-point grounding detection logic (i.e., difference judgment) will be triggered only when 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 and the ground loop current. When the sum of the two meets the following conditions, it is judged that multiple point grounding occurs:

[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 segment setting can be performed according to 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, the data collected through experiments show that the multi-point grounding phenomenon will exhibit specific numerical characteristics under different current environments.

[0159] The following is sample data:

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

[0161] Under abnormal conditions: When multiple points are grounded, the measured N loop current and ground current will exceed 5mA, and may even reach hundreds of mA in some extreme cases. To this end, an adjustable threshold value is designed to ensure accurate abnormality discrimination in different operating environments. The following takes 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 make a preliminary judgment on the current of the N loop and the ground loop to evaluate whether it exceeds the preset threshold range. This preset value is usually debugged based on actual engineering needs to ensure sensitivity while minimizing the probability of false alarms. Once the current value of any set of loops exceeds the threshold value, the device will automatically enter the multi-point grounding judgment logic to further analyze the abnormal state. After confirming that the current exceeds the threshold, the device will calculate the absolute value of the sum of the current of the N loop and the ground loop. This difference is calculated accurately to the milliampere (mA) level and compared with the preset error current value. The original intention of setting this error current value is to allow a certain degree of deviation to exist in consideration of the inevitable current fluctuations of the measuring instrument and cable during operation, so as to avoid the device from misjudging the normal working state. If the absolute value of the sum does not exceed the set error current, we will regard this situation as multi-point grounding, and the device will immediately trigger the alarm mechanism. The alarm information will be recorded in the monitoring log for subsequent analysis; the above logic judgment structure is implemented through multi-level analysis modules, which not only improves the accuracy of current loop abnormality identification, but also significantly enhances the reliability and real-time performance of the monitoring device. The device calculates and processes the data of the acquisition module layer by layer in real time to eliminate unnecessary interference, thereby more accurately identifying abnormal conditions and preventing false alarms caused by current fluctuations.

[0166] In practical applications, considering the current measurement accuracy and potential interference between acquisition modules, the multi-point grounding current threshold is usually set to 5mA (adjustable), and the setting can be further adjusted based on the actual current data collected. When the device detects that the current average of the N loop and the grounding loop exceeds 5mA, the device will activate the multi-point grounding alarm module, and the error current value can be adjusted dynamically in real time according to the collected current. The smaller the action current, the smaller the braking current, and the larger the action current, the larger the braking current. Such setting considerations not only prevent the misjudgment of faults, but also improve the sensitivity of fault discrimination. Through such hierarchical analysis, the current anomaly discrimination model is continuously optimized to obtain a more accurate multi-point grounding fault discrimination capability.

[0167] 4. Response and signal transmission

[0168] The multi-point grounding alarm is transmitted to the backstage of the substation or a remote location in the form of an electrical signal through a pair of cables. 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 the traditional contact temperature measurement method, the non-contact technology can effectively avoid the measurement error 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] In order to further improve the accuracy of temperature monitoring, the present invention adopts a dot matrix division technology to divide the monitoring panel into a plurality of fine square dot matrices. Each terminal corresponds to the corresponding square dot matrix, and this high-resolution spatial division ensures the localization and refinement of temperature data acquisition. Through this method, not only can the accurate mapping of temperature be achieved, but also the abnormal temperature distribution can be accurately located, providing more abundant and reliable information for subsequent data processing. Each square can not only independently monitor the temperature changes inside it, but also form a rich data set on the overall monitoring panel to help achieve more accurate temperature mapping. The present invention designs a flexible threshold setting function, allowing users to customize the threshold of temperature monitoring according to actual application scenarios and equipment characteristics. On the display and input module, users can conveniently enter specific upper and lower temperature limits, and the device uses it as a benchmark for real-time monitoring. If the monitored temperature exceeds these set thresholds, the analysis and control module will promptly identify the abnormal state. This process relies on a complex signal processing algorithm, which ensures that any deviation from the normal working range can be efficiently and accurately identified by quickly analyzing and comparing the temperature data of each square. 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] Response and Information Transmission After identifying an abnormality, the analysis and control module will respond quickly. First, the operator will be alerted through the sound and light alarm module to remind him to pay attention to the abnormal state of the equipment so that timely measures can be taken. This alarm mechanism not only improves the vigilance of on-site operators, but also effectively shortens the 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 the detector inside the non-contact infrared temperature sensor receives infrared energy, it converts it into a temperature value according to the black body 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 square dot matrices. Each terminal corresponds to only one square area, thus realizing the localized and detailed collection of temperature data.

[0177] d. The analysis and control module receives temperature data from the non-contact infrared temperature sensor. The user sets the upper and lower temperature limits as temperature thresholds through the display and input module. The analysis and control module quickly analyzes and compares the temperature data of each grid to determine whether it exceeds the temperature 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 situations of the current secondary circuit, and 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 above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A current loop monitoring device based on acquisition parameter difference comparison method, characterized in that: include: A collection module (101) 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 ; An 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 point grounding occurs; A 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 generate an alarm. A display and input module (104), connected to the analysis and control module (102), is used to display whether a current secondary circuit to be detected has multiple grounding points; 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 measuring sensor (105) is respectively 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 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 wiring terminal with a temperature threshold value, and determine whether the temperature value of each wiring 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.

2. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 1 is 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 is characterized in that: 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 , triggers the difference judgment.

4. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 3 is characterized in that: The specific method of difference judgment is: The absolute value of the sum of the currents of the N loop and the ground loop 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.

5. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 3 is characterized in that: There are three settings for the error current ΔI. The specific calculation formula is as follows:

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

7. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 6 is 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 given.

8. The current loop monitoring device based on the acquisition parameter difference comparison method according to claim 7 is characterized in that: It also includes 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.

9. 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 display the judgment result of whether the temperature value of each connection terminal obtained by the analysis control module (102) exceeds the temperature threshold.

10. 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.

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