A method and apparatus for intelligent monitoring and fault diagnosis of control loops

Abstract

This invention relates to a method for intelligent monitoring and fault diagnosis of control circuits, including monitoring of switches with voltage levels of 110kV and below and monitoring of switches with voltage levels of 220kV and above. Monitoring of switches with voltage levels of 110kV and below includes the following steps: opening and closing operation; current acquisition; waveform recording and analysis; and termination. Monitoring of switches with voltage levels of 220kV and above includes the following steps: opening and closing operation; current and voltage acquisition; waveform recording and analysis; disconnection of control power supply; and termination. The device of this invention includes a current acquisition unit, a voltage acquisition unit, an intelligent waveform recording unit, a control unit disconnection unit, and a wireless communication unit. This invention addresses the lack of a comprehensive monitoring mechanism for control circuits in substations. By adding control circuit monitoring functionality, more comprehensive monitoring and fault diagnosis of control circuits can be achieved without altering the original control circuit.

Description

Technical Field

[0001] This invention relates to the field of maintenance technology, specifically to a method and apparatus for intelligent monitoring and fault diagnosis of control loops. Background Technology

[0002] A high-voltage pulse DC control technology is used to plot the V / A characteristic curve of the tested electromagnet coil and output the results for comparison. The device employs high-voltage pulse time control output technology, ensuring that the high-voltage pulse output is controlled within milliseconds for each test. This guarantees that the total output power will not exceed the short-circuit withstand capability of the tested coil, thus ensuring test safety and preventing the tested control coil's state from being affected by the test. The circuit breaker control coil inter-turn insulation fault detection device includes a high-voltage signal output device, a control detection output device, and connecting wires. The control detection output device is the core control component of the system, responsible for input signal control and measurement result output. The principle of the circuit breaker control coil inter-turn insulation fault detection system is as follows: Figure 1 As shown.

[0003] High-voltage pulse control technology is used to plot the V / A characteristic curve of the electromagnet coil under test. By comparing it with the V / A characteristic curve of a standard electromagnet coil, when the V / A characteristic curve of the measured coil at the same frequency and voltage is found to be abnormal, it can be determined that the overall magnetic flux and magnetic reluctance of the electromagnet coil under test are reduced, that is, there is an inter-turn insulation fault.

[0004] Using standard coil data commonly used in actual working environments, standard coil waveforms are plotted, and these are used as a basis to judge the quality of other coils. Finally, the device is set up with multiple standard waveforms pre-stored based on standard coils in the field, and test experiments are conducted. The tests reveal shortcomings in existing technology:

[0005] 1) The above method requires removing the coil from the mechanism for testing in conjunction with maintenance and testing, which is cumbersome and not feasible.

[0006] 2) The above method cannot be used to monitor switches in operation;

[0007] 3) The control circuit has many components and many types of faults. This method only tests the insulation of the opening and closing coils and cannot test all the components of the control circuit or determine the cause of the fault based on the fault condition. There are no relevant technical means to deal with the faults that occur during the maintenance and testing process and minimize the impact of the faults. Summary of the Invention

[0008] The purpose of this invention is to provide a method and apparatus for intelligent monitoring and fault diagnosis of control circuits to reduce the adverse effects of coil burnout on switching mechanisms, and to reduce the increase in equipment maintenance time or forced power outages caused by control circuit failures.

[0009] The technical solution of this invention:

[0010] A method for intelligent monitoring and fault diagnosis of control loops, including non-contact monitoring of switches with voltage levels of 110kV and below and multi-analog monitoring of switches with voltage levels of 220kV and above.

[0011] Monitoring and fault diagnosis of switches with voltage levels of 110kV and below includes the following steps: opening and closing operations; current acquisition; waveform recording and analysis; and termination.

[0012] Monitoring and fault diagnosis of switches with voltage levels of 220kV and above includes the following steps: opening and closing operations; current and voltage acquisition; waveform recording and analysis; disconnection of control power supply; and termination. Preferably, monitoring and fault diagnosis of switches with voltage levels of 110kV and below specifically includes the following steps: long-term monitoring using a current acquisition device and an intelligent waveform recorder. The acquired current is transmitted wirelessly to the intelligent waveform recorder. The intelligent waveform recorder monitors the current waveform of each switch opening and closing operation and compares it with a standard waveform. Based on changes in the current waveform, potential hazards in the control circuit components are identified, and alarm thresholds are set. Once the current exceeds the limit, the intelligent waveform recorder automatically alarms, reminding maintenance personnel to schedule time to address the hazard.

[0013] Preferably, for switches with voltage levels of 220kV and above, intelligent monitoring and fault diagnosis devices are installed only during power outage maintenance.

[0014] Preferably, the monitoring and fault diagnosis of switches with voltage levels of 220kV and above specifically includes the following steps: a current acquisition device is mounted on the opening and closing circuit behind the protection panel for non-contact current acquisition during the opening and closing process; a voltage acquisition device acquires the voltage across the auxiliary contacts of the switch during the opening and closing process; the acquired voltage and current are transmitted wirelessly to an intelligent waveform recording device; the intelligent waveform recording device records the acquired analog quantity information and sets overcurrent and overtime thresholds; once the current exceeds the limit, an alarm command can be quickly issued and transmitted wirelessly to the control power cut-off device; the control power cut-off device is mounted on the circuit breaker; once the cut-off device receives the alarm command, it quickly opens the circuit breaker and cuts off the control power.

[0015] Preferably, the coil burnout generally takes more than 10 seconds, and an alarm message can be issued as long as the current continues for 0.1 seconds. The control switch can be turned off within 3 seconds via wireless transmission of instructions. After the control power is turned off, the intelligent waveform recording device combines the collected voltage and current to intelligently analyze and determine the cause of the fault. Based on the analysis results, maintenance personnel take measures to deal with the problem.

[0016] A device for intelligent monitoring and fault diagnosis of control loops includes a current acquisition unit, a voltage acquisition unit, an intelligent waveform recording unit, a control unit disconnection unit, and a wireless communication unit.

[0017] The current acquisition unit and voltage acquisition unit transmit signals to the intelligent waveform recording unit via a wireless communication unit; the intelligent waveform recording unit transmits signals to the control unit's cutoff unit via a wireless communication unit.

[0018] Preferably, the current acquisition unit adopts a passive magneto-optical glass-type electronic current transformer, and calculates the control loop current by combining Faraday's law of magneto-optical induction.

[0019] The voltage acquisition unit is implemented by connecting a 200V DC voltmeter in series in the circuit. The analog voltage measured by the voltmeter is converted into a digital value by an A / D converter. The result is then stored locally and wirelessly transmitted to the intelligent waveform recording unit through electronic counter technology. The locally stored digital value can be directly accessed and displayed on the local display screen.

[0020] Preferably, the intelligent waveform recording unit acquires voltage and current through wireless transmission technology; the intelligent waveform recording unit stores standard waveforms and automatically compares them with test waveforms to intelligently analyze potential problems in the control circuit;

[0021] The intelligent waveform recording unit can send a command to the control unit to cut off the device at the same time as the device alarms.

[0022] Preferably, the control unit cuts off the overcurrent information and converts it into a wireless command to receive and control the auxiliary element, which then synchronously drives the control switch to open via a mechanical latch.

[0023] Preferably, the wireless communication unit adopts 5G technology;

[0024] Alternatively, SIM cards can be placed in each unit, and network cards required for 5G communication can be integrated to enable wireless communication between devices.

[0025] The beneficial effects of this invention are:

[0026] This invention addresses the lack of a comprehensive monitoring mechanism for the control circuits within substations. By adding monitoring functions to the control circuits, more comprehensive monitoring can be achieved without altering the original control circuits. It allows for early prediction of potential control circuit hazards and automatic, rapid response and handling during fault occurrences. This effectively reduces the frequency of accidents such as "coil burnout" and "closing / opening resistor burnout" during switching operations, minimizes the adverse effects of coil burnout on the switching mechanism, and significantly reduces the increase in equipment maintenance time or forced power outages caused by control circuit faults.

[0027] 1) High feasibility. Using photoelectric current transformers for current monitoring in the relay protection room not only does not affect the normal operation of the original control circuit, but also has the characteristics of convenient installation, strong anti-interference ability, high measurement accuracy, safety, and is not affected by environmental factors such as switch vibration;

[0028] 2) Online monitoring. Given the automatic opening and closing characteristics of 110kV and below switches, it enables non-contact continuous monitoring without power interruption, and can record the current waveform during the opening and closing process, compare it with standard waveforms, and predict control circuit faults in advance.

[0029] 3) Timely handling methods. Considering the characteristics of 220kV and above switches, multiple analog quantities are monitored during the pre-testing process. If overcurrent or over-time is detected in the control circuit, immediate corrective measures are taken to avoid adverse effects from prolonged excitation of the control circuit.

[0030] 4) Intelligent analysis of fault causes. By monitoring the current waveform during the opening and closing process and the voltage of several important nodes in the 500kV and 220kV switch control circuits, the cause of the fault can be quickly determined. Attached Figure Description

[0031] Figure 1 Background technology: Schematic diagram of an inter-turn insulation fault detection system for circuit breaker control coils;

[0032] Figure 2 This is a general implementation diagram of the present invention;

[0033] Figure 3 This is a simplified flowchart of the implementation process of the 110kV and below voltage level switch of the present invention.

[0034] Figure 4 This is a simplified flowchart of the implementation process of the 220kV and above voltage level switch according to Embodiment 2 of the present invention;

[0035] Figure 5 This is a schematic diagram illustrating the principle of a passive magneto-optical glass-type electronic current transformer according to an embodiment of the present invention.

[0036] Figure 6This is a schematic diagram of Faraday's law of magneto-optical induction according to an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the voltage acquisition unit according to an embodiment of the present invention;

[0038] Figure 8 The voltage measurement method in this embodiment of the invention adopts a measurement principle diagram similar to that of a multimeter;

[0039] Figure 9 This invention relates to a combined gate control circuit and a two-group gate control circuit as described in Embodiment 1.

[0040] Figure 10 This is a diagram illustrating a method for obtaining Td according to an embodiment of the present invention;

[0041] Figure 11 This is a diagram illustrating a method for synchronizing sampling times according to an embodiment of the present invention.

[0042] Figure 12 This is a schematic diagram of the power supply cut-off unit according to an embodiment of the present invention;

[0043] Figure 13 This is the analog message structure for the 5G control loop. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] There are currently three main methods used to inspect the insulation of the opening and closing coils:

[0046] 1) During the pre-testing of maintenance, remove the opening and closing coils and conduct an insulation test on the opening and closing coils to check whether the coil insulation is in good condition;

[0047] 2) To add a temperature sensor inside the mechanism, the excitation state of the coil can be identified from the side by monitoring the temperature of the opening and closing coil;

[0048] 3) Modify the opening and closing control circuit, and cut off the control circuit through a time relay to avoid the coil being energized for a long time.

[0049] However, methods 1 and 2 mentioned above did not solve the problem of coil burnout, and they were difficult to implement. Method 3, which modifies the control circuit, violates the requirements of the relay protection regulations. Therefore, the above solutions are not currently used in substations for burnout accidents.

[0050] This invention primarily addresses the operational status of equipment in ultra-high voltage (UHV) substations, employing targeted methods to reduce the frequency of coil or switching resistor burnout. The specific problems solved are as follows.

[0051] 1) The 110kV and below low-voltage side of the station is only responsible for voltage regulation and automatic switching according to the load. Therefore, the low-voltage side switches are opened and closed many times and short-term faults have little impact on the overall operation of the substation. Based on the above characteristics, this patent uses photoelectric current transformers to realize long-term monitoring of the opening and closing control circuit. By recording and analyzing the instantaneous current waveform of opening and closing, potential problems in the control circuit can be predicted in advance.

[0052] 2) For 220kV and above switches in the station, which do not open or close during normal operation, and are only opened or closed after the maintenance period is met, the maintenance period is generally 6 years. Based on the above characteristics, it was decided to monitor only during the maintenance test. Moreover, as the years increase, the components of the equipment are at risk of aging, and the failure of the control circuit components may occur suddenly. Relying solely on prediction is not enough to meet the requirements. Therefore, it is necessary to take automatic measures when a fault occurs to avoid accidents. At the same time, the cause of the fault should be automatically determined through monitoring, and corresponding measures should be taken to deal with it.

[0053] like Figure 2 As shown, this embodiment is improved to prepare a device for intelligent monitoring and fault diagnosis of control loops, including a current acquisition unit, a voltage acquisition unit, an intelligent waveform recording unit, a control unit cutoff unit, and a wireless communication unit; the current acquisition unit and the voltage acquisition unit transmit signals to the intelligent waveform recording unit through the wireless communication unit; the intelligent waveform recording unit transmits signals to the control unit cutoff unit through the wireless communication unit.

[0054] I. Current Acquisition Unit

[0055] Passive magneto-optical glass-type electronic current transformers have advantages such as requiring no power supply, strong anti-interference capability, convenient installation, and high measurement accuracy. Therefore, passive magneto-optical glass-type electronic current transformers are used, such as... Figure 5 As shown, combining Faraday's law of magneto-optical induction, the control loop current can be calculated. The Faraday magneto-optical effect is as follows: Figure 6 As shown.

[0056] II. Voltage Acquisition Unit

[0057] The DC voltage unit of the control circuit adopts a DC voltage measurement principle similar to that of a multimeter, and has been modified to meet actual usage requirements. Its schematic diagram is shown below. Figure 7 As shown,

[0058] As shown in the figure, this device can simultaneously measure and record four sets of voltages, and the measurement results can be displayed locally on the screen. Based on the characteristics of the control loop voltage, a voltage range of 220V can be selected.

[0059] III. Intelligent Waveform Recording Unit

[0060] The intelligent waveform recording unit is similar to a traditional fault waveform recorder, but with further improvements.

[0061] The main differences are as follows:

[0062] 1) Traditional waveform recorders collect information through fiber optic or cable connections, while intelligent waveform recorders collect voltage and current data through wireless transmission technology.

[0063] 2) Traditional waveform recorders can only compare two waveforms manually, while intelligent waveform recording units store standard waveforms and automatically compare them with test waveforms to intelligently analyze potential problems in the control loop;

[0064] 3) Traditional waveform recorders can only receive information and issue alarms, but cannot send commands. Intelligent waveform recorders can send commands to the control unit to cut off the device at the same time as the device issues an alarm.

[0065] The principles for recording, storing, displaying, and alarming voltage and current are basically the same.

[0066] IV. Control Unit Cut-off Unit

[0067] Drawing on the principles of residual current circuit breakers or current limiting control switches, and further improving upon them, the original overcurrent and other information quantities are changed to wireless command reception to control the action of auxiliary components, which are then synchronously driven to open the control switch through a mechanical latch.

[0068] V. Wireless Communication Unit

[0069] All four units mentioned above require wireless communication units to communicate. With the continuous development of substation technology, future substations will achieve full coverage of 5G technology. Therefore, adopting 5G communication will be more in line with the development needs of future substations.

[0070] The SIM card can be placed in each unit, and the network card required for 5G communication can be integrated to enable wireless communication between devices.

[0071] The root cause of coil burnout is prolonged excitation of the opening and closing coils. However, there is a lack of effective monitoring methods for the magnitude and duration of the control circuit current. In general, it is not permissible to modify or add instruments that are in direct contact with the control circuit for monitoring in operating equipment. If monitoring methods can be adopted to monitor the control circuit, the monitoring methods for the control circuit can be optimized, which is highly feasible.

[0072] Based on the operational status of ultra-high voltage and extra-high voltage substation equipment, switches can be divided into two categories:

[0073] 1) Switches at voltage levels of 110kV and below are generally used to connect reactive power equipment in the substation. Reactive power equipment is automatically switched on and off as the load changes, and the switching is opened and closed relatively frequently. However, short-term faults of the switch have little impact on the operation of the power grid.

[0074] 2) Switches of voltage levels of 220kV and above are generally only opened and closed during maintenance and testing. The general maintenance period is 6 years. The components that make up the control circuit are at risk of aging. The control circuit failure often occurs suddenly, rather than as a gradual process. The control circuit only has current during the opening and closing of the switch. It is difficult to solve the corresponding problems by current monitoring and analysis alone. However, the switch failure has a significant impact on the power grid, and the normal operation of equipment is often affected during maintenance and testing.

[0075] Example 1

[0076] like Figure 3 As shown, based on the operation of the switch, the following measures are taken:

[0077] 1) For voltage switches of 110kV and below, since they are opened and closed many times and are all automatically switched, long-term current monitoring is of certain significance. By recording and analyzing the current waveform, potential problems in the control circuit can be predicted in advance and handled in conjunction with power outage operations.

[0078] For switches with voltage levels of 110kV and below, a current acquisition device and an intelligent waveform recorder are used for long-term monitoring. The acquired current is transmitted wirelessly to the intelligent waveform recorder. The intelligent waveform recorder monitors the current waveform of each switch opening and closing and compares it with a standard waveform. As the current waveform changes, it identifies potential problems in the control circuit components and sets alarm thresholds. Once the current exceeds the limit, the intelligent waveform recorder automatically alarms, reminding maintenance personnel to schedule time to address the problem.

[0079] By developing an intelligent monitoring and fault diagnosis device for the control circuit, it is possible to continuously track, monitor and record the trip and close circuit current without changing the original control circuit or moving any mechanical components, effectively preventing coil and plug-in burnout.

[0080] Example 2

[0081] like Figure 4 As shown, based on the operation of the switch, the following measures are taken:

[0082] For switches with voltage levels of 220kV and above, current monitoring is conducted during the pre-testing and maintenance process, and the current waveform is recorded and analyzed. At the same time, a mechanical locking device is used to instantly disconnect the control power supply in case of overcurrent or over-time abnormalities in the control circuit, so that the current in the control circuit can be reduced to zero instantly, thus preventing burn-out accidents. In addition, a voltage monitoring device is added to the control circuit, and the collected data is recorded. Combined with voltage and current data, the fault point can be quickly analyzed, and targeted measures can be taken immediately on site.

[0083] For switches with voltage levels of 220kV and above, the aforementioned devices are installed only during power outage maintenance. The current acquisition device is mounted on the closing / opening circuit behind the protection panel to collect current data during the closing / opening process. The voltage acquisition device collects the voltage across the auxiliary contacts of the switch during the closing / opening process. The collected voltage and current values ​​are transmitted wirelessly to an intelligent waveform recorder. The intelligent waveform recorder records the collected analog information and sets overcurrent and over-time thresholds. Once the current exceeds the limit, an alarm command is quickly issued and transmitted wirelessly to the control power disconnection device. The control power disconnection device is mounted on the circuit breaker. Once the disconnection device receives the alarm command, it quickly opens the circuit breaker, disconnecting the control power. Generally, coil burnout typically takes more than 10 seconds, and an alarm message is issued if the current persists for 0.1 seconds. Through wireless transmission, the control switch can disconnect the control power within 3 seconds. After disconnecting the control power, the intelligent waveform recorder, combined with the collected voltage and current values, intelligently analyzes and determines the cause of the fault. Based on the analysis results, maintenance personnel can quickly take measures to address the issue.

[0084] By developing an intelligent online monitoring device for the control circuit, it is possible to continuously track, monitor, and record the trip and close circuit current without changing the original control circuit or moving any mechanical components, effectively preventing coil and plug-in burnout.

[0085] Example 3

[0086] The hardware in this invention includes the following:

[0087] I. Current Acquisition Unit

[0088] For voltage levels of 110kV and below, there is one combined switch and one set of switch control circuits, with corresponding wire core numbers 7 and 37. For voltage levels of 220kV and above, there is one combined switch control circuit and two sets of switch control circuits, with corresponding wire core numbers 107A, 107B, 107C, 137A, 137B, 137C, 237A, 237B, and 237C.

[0089] The current acquisition unit consists of magneto-optical glass, optical fiber, light source, and processing system. The processing system uses a photoelectric conversion module to convert the output optical signal into an electrical signal, and after data processing, the electrical signal is converted into data, which is finally output wirelessly.

[0090] When a beam of plane-polarized light passes through a magneto-optical medium placed in a magnetic field, the plane of polarization of the light rotates with the magnetic field parallel to the direction of the light. This rotation angle is called the Faraday rotation angle, and the phenomenon is known as the Faraday effect. The magneto-optical effect refers to various optical phenomena caused by the interaction between magnetized matter and light. This effect originates from the magnetization of matter and profoundly reflects the close relationship between light and the magnetism of matter. When a beam of linearly polarized light emitted from a light source passes through magneto-optical glass placed in a set magnetic field, the plane of polarization of the linearly polarized light rotates linearly with the magnitude of the magnetic field parallel to the direction of the light. By using a suitable analyzer to convert the angle information into light intensity information, and a photoelectric conversion module to convert the light intensity signal into an electrical signal, the primary current passing through the conductor can be calculated after data processing.

[0091] II. Voltage Acquisition Unit

[0092] Switches at voltage levels of 220kV and above involve one combined tripping control circuit and two combined tripping control circuits, with corresponding conductor numbers of 107A, 107B, 107C, 137A, 137B, 137C, 237A, 237B, and 237C, respectively. Taking the A-phase tripping control circuit of the switch as an example, as follows: Figure 9 As shown:

[0093] In the diagram, 52A is the auxiliary contact of the switch. When the switch is in the open position, its normally open auxiliary contact is open. After closing, the normally open contact 52A closes. If the switch is in the closed position, 52A is conducting. When the control box receives the closing command from the protection or monitoring device, the closing node in the control box closes, the control circuit is connected, the tripping coil in the operating mechanism is energized, and after the switch trips, the auxiliary contact 52A of the switch separates, cutting off the control circuit.

[0094] If the 52A node fails to perform the operation from closed to open during the opening process, or if the mechanism jams, causing the control circuit to remain open, the opening coil of the operating mechanism may burn out when the current flowing through the circuit exceeds 20 seconds.

[0095] When the switch is closed, node 52A is closed. At this time, the potentials of 137A and 137a should both be -110V. At the moment of opening, the potentials of 137A and 137a should be +110V. After the opening operation is completed, the potential of 137A should be 0V or +110V, while the potential of 137a should be -110V. By monitoring the potentials of 137A and 137a, the switch can be opened. By monitoring the voltages of 137A and 137a, control circuit faults can be identified and the location of the fault point can be determined.

[0096] The principle of coil burnout in the closing control circuit and the method for fault point identification are similar to those in the opening control circuit. Since voltage monitoring is required on both sides of the switch auxiliary contacts, a total of 18 wiring terminals and 1 grounding terminal are needed. Figure 7 As shown, the voltage measurement method adopts a measurement principle similar to that of a multimeter. It measures the DC voltage of each circuit, converts the analog voltage into a digital value using a digital-to-analog converter, records the value, and displays it on a screen. Figure 8 .

[0097] III. Intelligent Waveform Recording Unit

[0098] The device's hardware system mainly consists of a wireless acquisition module, a processor, and a background analysis module.

[0099] The wireless acquisition unit collects voltage and current data respectively and outputs the collected data to the processor via the internal bus. Since the voltage and current data are taken from different locations, and vector acquisition requires that the collected current and voltage data be from the same moment, a delay inevitably occurs during wireless transmission. According to the characteristics of power frequency quantities, a 1ms delay error corresponds to an 18° phase error. Before the processor calculates the phase difference using the zero-crossing detection method, it needs to eliminate the delay.

[0100] The data synchronization function is implemented in the synchronization modulation module. The prerequisite for wireless transmission and data comparison between the main table and the auxiliary table is that the relative time of the two tables is zero, the sampling frequency of the main and auxiliary tables is the same, and the sampling time corresponding to each sampling point is also the same. Only in this way can the data sampled by the two tables be meaningful for comparison. The phase synchronization between the main table and the auxiliary table is similar to the synchronization principle of fiber optic differential protection in relay protection.

[0101] The current and voltage acquisition units and the intelligent waveform recording unit transmit data wirelessly. As long as the acquisition unit and the waveform recording unit are stably connected, their transmission delay Td is a fixed constant. Time synchronization means accurately calculating Td and compensating for it when comparing the sampled data of the main and secondary tables. Figure 10 This is the method to obtain Td. Figure 11 It is a method for correcting the synchronization of sampling time.

[0102] Figure 10The black dots in the diagram represent sampling times, the interval between two adjacent dots characterizes the sampling frequency, and the vertical distance between two adjacent black dots represents the sampling time difference ΔTs between the primary and secondary tables. Although the sampling frequencies of the primary and secondary tables are the same, given the unpredictable power-on times of the two tables, it is impossible to achieve synchronous sampling times. The significance of synchronizing sampling times is to ensure that... Figure 11 ΔTs is adjusted to zero. The main meter terminal is the reference terminal, and the secondary meter terminal is the adjustment terminal.

[0103] During synchronization, the channel transmission delay Td must first be measured. The slave table sends a message to the master table at time tss, using its relative clock as a reference. The master table records the reception time tmr of this message, also using its relative clock as a reference. Then, at the next sampling time tms, it transmits the time difference tms - tmr as the message content to the slave table. The slave table then records the time tsr at which it receives the message from the master table, and can calculate the wireless transmission delay Td. After measuring Td, the slave table can calculate ΔTs by combining it with the time tsr. Subsequently, the slave table makes multiple small-step adjustments to the sampling time until the sampling time difference ΔTs reaches zero, at which point both ends synchronize sampling.

[0104] The processor is used for receiving, parsing, storing, recording fault waveforms, and sending alarm signals from the acquisition module. It employs a high-performance quad-core network processor with a 64-bit MIPS64 architecture. Through seamless multi-core collaboration, it achieves data reception, parsing, and storage speeds of 1Gbps-2Gbps, ensuring outstanding performance and reliability. This unit incorporates a high-speed hardware compression module, using a compression algorithm combining LZ77 and Huffman coding, achieving a compression efficiency of 3-6 times and a compression rate of up to 2.5Gbps.

[0105] Backend Analysis Module

[0106] This module is used to complete the human-machine interface of the system, provide real-time on-site display functions, and has functions such as waveform analysis, parameter setting, operation status monitoring, and automatic comparison and analysis with standard waveforms.

[0107] The selected display screen should meet the following conditions:

[0108] (1) It can intuitively display voltage and current waveforms, analysis results, and parameter settings;

[0109] (2) It has high human-computer interaction performance, which facilitates waveform expansion and contraction as well as the relative comparison of different waveforms.

[0110] The DMT80480T070 touchscreen is used as the display screen, and its installation process is as follows:

[0111] (1) Determine the interface content based on business needs and create each interface using Photoshop;

[0112] (2) Assemble the touch screen and build its working circuit. The touch screen consists of three parts: an LCD screen, a microcontroller, and a memory. The computer stores the various interfaces in the touch screen's memory.

[0113] (3) Use DGUS to write a touch screen graphic display program.

[0114] The touchscreen displays information including the device homepage, real-time waveform monitoring, alarm waveform selection, comparison with standard waveforms, and parameter setting interface.

[0115] IV. Wireless Communication Unit

[0116] 5G (Fifth Generation Mobile Communication Technology) is a new generation of broadband mobile communication technology characterized by high speed, low latency, and massive connectivity. It serves as the network infrastructure for realizing the interconnection of humans, machines, and things. In the power sector, energy production includes five stages: power generation, transmission, transformation, distribution, and consumption. Currently, 5G applications in the power sector mainly focus on four stages: transmission, transformation, distribution, and consumption. Application scenarios primarily cover data acquisition and monitoring services as well as real-time control services.

[0117] A method for transmitting 5G analog data based on a routable sample value mechanism is adopted. On the traditional SV message structure, transport layer and network layer information are added to enable message transmission through the 5G network; differential protection data transmission is achieved. The message format is as follows: Figure 13 As shown.

[0118] V. Power Cut-off Control Unit

[0119] like Figure 12 The controlled contact is a normally open contact. When an alarm command is received, the controlled contact closes, the lower rod of the electromagnetic trip unit moves up, the lever pushes the hook to rotate clockwise, and after the hook is released, the chain is driven by the spring tension, causing the main contacts to separate, thereby disconnecting the control power supply.

[0120] The above description of the embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for intelligent monitoring and fault diagnosis of a control loop, characterized in that, This includes monitoring and fault diagnosis of switches with voltage levels of 110kV and below, and monitoring and fault diagnosis of switches with voltage levels of 220kV and above; non-contact monitoring of switches with voltage levels of 110kV and below, and multi-analog monitoring of switches with voltage levels of 220kV and above. Monitoring and fault diagnosis of switches with voltage levels of 110kV and below includes the following steps: Opening and closing operation; current acquisition; waveform recording and analysis; end; Monitoring and fault diagnosis of switches with voltage levels of 220kV and above includes the following steps: opening and closing operation; current and voltage acquisition; waveform recording and analysis; disconnection of control power supply; end; the current acquisition device is attached to the opening and closing circuit behind the protection panel for non-contact current acquisition during the opening and closing process. The monitoring of switches with voltage levels of 110kV and below specifically includes the following steps: long-term monitoring is carried out using a current acquisition device and an intelligent waveform recording device, and the acquired current is transmitted to the intelligent waveform recording device wirelessly. The intelligent waveform recording device monitors the current waveform of each switch opening and closing and compares it with the standard waveform. As the current waveform changes, it judges the potential hazards of the control circuit components and sets alarm thresholds. Once the current exceeds the limit, the intelligent waveform recording device will automatically alarm and remind maintenance personnel to arrange time to deal with the potential hazards. For switches with voltage levels of 220kV and above, intelligent monitoring devices are only installed during power outage maintenance. The monitoring and fault diagnosis of switches with voltage levels of 220kV and above specifically includes the following steps: The current acquisition device is installed on the opening and closing circuit behind the protection panel to collect current during the opening and closing process. The voltage acquisition device collects the voltage across the auxiliary contacts of the switch during the opening and closing process. The collected voltage and current are transmitted to the intelligent waveform recording device wirelessly. The intelligent waveform recording device records the collected analog quantity information and sets the overcurrent and overtime threshold. Once the current exceeds the limit, an alarm command can be quickly issued and transmitted wirelessly to the control power cut-off device. The control power cut-off device is installed on the circuit breaker. Once the cut-off device receives the alarm command, it quickly opens the circuit breaker and cuts off the control power. If the coil burns out for more than 10 seconds and the current continues for 0.1 seconds, an alarm message will be issued. The control switch will be activated to disconnect the power supply within 3 seconds via wireless transmission. After the power supply is disconnected, the intelligent waveform recording device will combine the collected voltage and current data to intelligently analyze and determine the cause of the fault. Based on the analysis results, maintenance personnel will take measures to handle the situation.

2. A device for intelligent monitoring and fault diagnosis of the control loop as described in claim 1, characterized in that, It includes a current acquisition unit, a voltage acquisition unit, an intelligent waveform recording unit, a control unit cutoff unit, and a wireless communication unit; The current acquisition unit and voltage acquisition unit transmit signals to the intelligent waveform recording unit via a wireless communication unit; the intelligent waveform recording unit transmits signals to the control unit's cutoff unit via a wireless communication unit.

3. The device for intelligent monitoring and fault diagnosis of control loops according to claim 2, characterized in that, The current acquisition unit uses a passive magneto-optical glass-type electronic current transformer and calculates the control loop current by combining Faraday's law of magneto-optical induction. The voltage acquisition unit is implemented by connecting a 200V DC voltmeter in series in the circuit. The analog voltage measured by the voltmeter is converted into a digital value by an A / D converter. The result is then stored locally and wirelessly transmitted to the intelligent waveform recording unit through electronic counter technology. The locally stored digital value can be directly accessed and displayed on the local display screen.

4. The device for intelligent monitoring and fault diagnosis of control loops according to claim 3, characterized in that, The intelligent waveform recording unit acquires voltage and current data through wireless transmission technology. The intelligent waveform recording unit stores standard waveforms and automatically compares them with test waveforms to intelligently analyze potential problems in the control loop; The intelligent waveform recording unit sends a command to the control unit to cut off the device at the same time as the device alarms.

5. The device for intelligent monitoring and fault diagnosis of control loops according to claim 4, characterized in that, The control unit cut-off unit converts the overcurrent information into wireless command reception to control the auxiliary components, which then synchronously drive the control switch to open via a mechanical latch.

6. The device for intelligent monitoring and fault diagnosis of control loops according to claim 5, characterized in that, The wireless communication unit adopts 5G technology; Alternatively, SIM cards can be placed in each unit, and network cards required for 5G communication can be integrated to enable wireless communication between devices.

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