On-line state diagnosis method and system for on-load capacity-regulating switch of permanent magnetic mechanism of transformer

Abstract

The invention relates to the technical field of transformers, in particular to an on-line state diagnosis method and system for an on-load capacity-regulating switch of a permanent magnetic mechanism of a transformer. A travel switch is arranged at the large and small capacity position of the capacity regulating switch; a Hall current sensor is arranged on an operation coil power supply loop; a voltage and current transformer is arranged on the incoming and outgoing line side of the transformer; the clamping stagnation state of the switch is judged by detecting the state of the travel switch and an operation coil current curve; the vacuum degree reduction degree is evaluated by analyzing the vacuum tube operation coil current change curve length; monitoring the current maximum value change of the operation coil power supply loop to diagnose the coil burning loss state; detecting the length increase condition of the current change curve to evaluate the capacity loss of the energy storage capacitor; and calculating a transition resistance value by using total loss, no-load loss and current according to the type of the transformer to judge the burning loss degree. According to the invention, comprehensive on-line diagnosis is carried out on key components of the capacity-regulating switch, the equipment reliability is improved, predictive maintenance is realized, the maintenance cost and the power failure risk are reduced, and powerful support is provided for intelligent management of a power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and in particular to an online state diagnosis method and system for an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer. Background Art

[0002] In urban commercial areas, development zones, industrial areas where the load changes greatly during the day and night, and in rural areas where the seasonal load changes greatly, the distribution transformer will experience the phenomenon of "a big horse pulling a small cart" during the period of less load, resulting in more power loss. The capacity-adjusting transformer can be switched to large and small capacities. When the transformer is under light load, it switches to small capacity to save energy. The key component of the capacity-adjusting transformer is its matching on-load capacity-adjusting switch. The performance of the transformer on-load capacity-adjusting switch directly determines whether the capacity-adjusting transformer can adjust the capacity normally. Therefore, it is necessary to test the performance of the on-load capacity-adjusting switch.

[0003] At present, the performance of on-load capacity-adjusting switches is tested before the capacity-adjusting switches are installed on the transformer or before they are put into operation after being installed on the transformer. The testing instruments are mainly mechanical property testers. The testing methods are mainly to test the synchronization consistency of the three-phase break during the capacity-adjusting process of the switch without high voltage in the main circuit of the capacity-adjusting switch and the resistance value of the transition resistor. Once the capacity-adjusting transformer is installed in the power system, the performance status is no longer monitored. However, the transformer on-load capacity-adjusting switch may also be stuck, the vacuum degree of the vacuum tube is reduced, the operating coil is burned, the energy storage capacitor capacity is reduced, and the transition resistor is burned. Only when the capacity-adjusting transformer fails, the capacity-adjusting switch is removed and tested without power to determine the fault point. This will inevitably cause the capacity-adjusting transformer to suddenly exit operation and cause unplanned power outages.

[0004] Therefore, the current performance detection method of the transformer on-load capacity-adjusting switch cannot perform performance detection on the on-load capacity-adjusting switch in operation, and cannot accurately manage the capacity-adjusting transformer. A method and system for online performance diagnosis of the transformer on-load capacity-adjusting switch is needed to detect possible problems of the transformer on-load capacity-adjusting switch in operation as early as possible. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the problem to be solved by the present invention is how to solve the problem that the current transformer on-load capacity-adjusting switch performance detection method cannot monitor the performance of the on-load capacity-adjusting switch in operation and cannot accurately manage the capacity-adjusting transformer. A method and system for online performance diagnosis of the transformer on-load capacity-adjusting switch is needed to detect possible problems of the transformer on-load capacity-adjusting switch in operation as early as possible.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, an embodiment of the present invention provides an online state diagnosis method for an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer, which includes deploying a travel switch and detecting the state of the travel switch and the current curve of the operating coil, and determining whether the switch is stuck and the stuck position;

[0009] Analyze the length of the current change curve of the vacuum tube operating coil, compare the normal and leaking states, and detect the maximum value change of the operating coil power supply circuit current;

[0010] Monitor the increase in the length of the current change curve of the operating coil power supply circuit. According to the type of transformer, use the total loss, no-load loss and current to calculate the transition resistance value to determine the degree of burnout.

[0011] The controller processes diagnostic data in real time, stores and uploads the information via 4G / 5G.

[0012] As a preferred solution of the online status diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer described in the present invention, wherein: the travel switch is installed at the large and small capacity positions of the capacity-adjusting switch, the Hall current sensor is installed in the power supply circuit of the operating coil, and the voltage and current transformer is installed on the input and output line sides of the transformer. The online status diagnosis mainly includes the stuck state of the on-load capacity-adjusting switch, the reduced vacuum degree state of the vacuum tube, the burned state of the operating coil, the loss state of the energy storage capacitor capacity, and the burned state of the transition resistor.

[0013] As a preferred solution of the online state diagnosis method of the permanent magnet mechanism on-load capacity-adjusting switch of the transformer of the present invention, the judgment of the action stagnation state of the on-load capacity-adjusting switch includes:

[0014] The controller detects the status of the travel switch at the large and small capacity positions after the capacity adjustment command is issued to determine whether the inherent action time has been exceeded;

[0015] Detect the position of the sudden change point of the current in the operating coil power supply circuit to determine the travel position of the switch stagnation point; when there is no abnormality in the operating circuit current but it exceeds the inherent action time, it is judged that the travel switch is damaged.

[0016] As a preferred solution of the online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer of the present invention, the judgment of the vacuum degree reduction state of the vacuum tube includes: detecting the length of the current change curve of the power supply circuit of the vacuum tube operating coil;

[0017] When the current change curve becomes longer when the switch is closed and becomes shorter when the switch is opened, it is judged that the vacuum degree of the vacuum tube is reduced;

[0018] The degree of vacuum tube leakage can be determined by comparing the length of the current change curve under normal state and complete leakage state.

[0019] As a preferred solution of the online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer of the present invention, the judgment of the burning state of the operating coil includes:

[0020] Detect the change of the maximum current in the current change curve of the operating coil power supply circuit; when the maximum current exceeds the preset threshold, it is determined that the operating coil is short-circuited and burned.

[0021] As a preferred solution of the online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer of the present invention, the judgment of the capacity loss state of the energy storage capacitor includes:

[0022] Detect the length of the current change curve of the operating coil power supply circuit; when the current change curve becomes longer during the bidirectional opening and closing of the switch, it is judged that the capacitor capacity begins to lose;

[0023] When the length of the change curve is close to the length of the current change curve corresponding to the minimum drivable operating coil energy storage capacitor, it is determined that the capacitor failure value has been reached.

[0024] As a preferred solution of the online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer of the present invention, the judgment of the burning state of the transition resistor includes:

[0025] For the high-voltage coil star-angle conversion type capacity regulating transformer, suppose the direct resistance ratio of the high-voltage coil to the low-voltage coil after the low-voltage coil is converted to the high-voltage side is k, then R is calculated using the following formula:

[0026]

[0027] Among them, R is the total resistance of the high-low voltage transition resistor after the high-voltage side, P0 is the no-load loss, P G is the total loss in the transition state, k is the direct resistance ratio of the high and low voltage coils, and I is the current on the high voltage side;

[0028] For high-voltage coil series-parallel conversion type capacity-adjusting transformer, R is calculated using the following formula:

[0029]

[0030] The degree of damage to the transition resistor is directly related to the R value. The degree of burnout of the transition resistor can be determined by judging the difference between R and the normal value.

[0031] In a second aspect, an embodiment of the present invention provides an online state diagnosis system for an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer, which includes a construction module, deploys a travel switch and detects the state of the travel switch and the current curve of the operating coil, and determines whether the inherent action time is exceeded;

[0032] The comparison module analyzes the length of the current change curve of the vacuum tube operating coil, compares the normal and leaking states, and detects the maximum value change of the operating coil power supply circuit current;

[0033] The judgment module monitors the increase in the length of the current change curve of the operating coil power supply circuit, and calculates the transition resistance value based on the total loss, no-load loss and current according to the transformer type to judge the degree of burning;

[0034] Output module, the controller processes diagnostic data in real time, stores and uploads information via 4G / 5G.

[0035] In a third aspect, an embodiment of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, the steps of the online status diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer as described in the first aspect of the present invention are implemented.

[0036] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, the steps of the online status diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer as described in the first aspect of the present invention are implemented.

[0037] The beneficial effects of the present invention are as follows: the present invention can realize online diagnosis of various key information such as the stuck state of the on-load capacity regulating switch of the permanent magnet mechanism, the reduced vacuum degree state of the vacuum tube, the burned state of the operating coil, the capacity loss state of the energy storage capacitor, and the burned state of the transition resistor.

[0038] It can realize the storage and upload of capacity regulating switch status data, thus assisting transformer managers to plan power outages in advance to replace or repair capacity regulating transformers. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 It is a flow chart of an online state diagnosis method of an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer;

[0041] Figure 2 A computer device diagram for an online state diagnosis method of an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer;

[0042] Figure 3It is a schematic diagram of a current curve of an operating coil power supply circuit when the switch is stuck in an online state diagnosis method of an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer;

[0043] Figure 4 It is a schematic diagram of the current curve of the operating coil power supply circuit when the vacuum degree of the vacuum switch of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer is reduced;

[0044] Figure 5 It is a schematic diagram of the current curve of the power supply circuit when the operating coil of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer is burned out;

[0045] Figure 6 It is a schematic diagram of the current curve of the power supply circuit when the capacity of the energy storage capacitor decreases in the online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer;

[0046] Figure 7 The schematic diagram of the high-voltage coil star-angle conversion type capacity-adjusting transformer for the online state diagnosis method of the on-load capacity-adjusting switch of the transformer permanent magnet mechanism;

[0047] Figure 8 The schematic diagram of the high-voltage coil series-parallel conversion type capacity-adjusting transformer is provided for the online status diagnosis method of the on-load capacity-adjusting switch of the transformer permanent magnet mechanism. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0049] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0050] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or selective embodiment that is mutually exclusive with other embodiments.

[0051] Example 1

[0052] Reference Figure 1-2 , which is the first embodiment of the present invention, provides an online state diagnosis method for an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer, comprising:

[0053] S100: deploy the travel switch and detect the travel switch state and the operating coil current curve to determine whether the switch is stuck and the stuck position;

[0054] S200: Analyze the length of the current change curve of the vacuum tube operating coil, compare the normal and leaking states, and detect the maximum value change of the current in the operating coil power supply circuit;

[0055] S300: Monitor the increase in the length of the current change curve of the operating coil power supply circuit, and calculate the transition resistance value based on the type of transformer using the total loss, no-load loss and current to determine the degree of burnout;

[0056] S400: The controller processes diagnostic data in real time, stores and uploads the information via 4G / 5G.

[0057] A travel switch is installed at the large and small capacity positions of the capacity regulating switch, a Hall current sensor is installed in the operating coil power supply circuit, and a voltage and current transformer is installed on the input and output line sides of the transformer. The online status diagnosis mainly includes the stuck state of the on-load capacity regulating switch, the reduced vacuum degree of the vacuum tube, the burned state of the operating coil, the loss state of the energy storage capacitor capacity, and the burned state of the transition resistor.

[0058] The above-mentioned on-load capacity regulating switch action stuck state can be solved by the following steps:

[0059] The controller of the on-load capacity-adjusting switch determines whether a jam occurs by detecting whether the travel switches at the large-capacity position and the small-capacity position of the capacity-adjusting switch exceed the inherent action time range of the capacity-adjusting switch after issuing the capacity-adjusting command;

[0060] By detecting the position of the current mutation point in the power supply circuit of the capacitance regulating switch operating coil, the travel position of the switch stagnation point can be determined. When there is no abnormality in the operating circuit current, it can be determined that the travel switch is damaged.

[0061] The vacuum degree of the vacuum tube is reduced by the following steps:

[0062] By detecting the length of the current change curve of the power supply circuit of the vacuum tube switch operating coil in the capacity regulating switch, if the current change curve becomes longer when the vacuum tube is closed and becomes shorter when the vacuum tube is opened, it is judged that the vacuum degree of the vacuum tube is reduced;

[0063] By comparing the two situations when the vacuum tube is normal and when the vacuum tube is completely leaking, the length of the current change curve when the vacuum tube is opened and closed can determine the degree of leakage of the vacuum tube.

[0064] The operating coil burnout state can be checked by the following steps:

[0065] By detecting the maximum current value in the current variation curve of the power supply circuit of each operating coil of the capacitance regulating switch, it is determined whether the operating coil is in a short-circuit burnout state.

[0066] The energy storage capacitor capacity loss state can be determined by the following steps:

[0067] By detecting the length of the current change curve of each operating coil power supply circuit in the capacitance adjustment switch, if the current change curve becomes longer during the opening and closing process of the switch, it means that the capacitance begins to lose;

[0068] When the length of the variation curve is close to the length of the current variation curve corresponding to the minimum drivable operating coil energy storage capacitor, the capacitor failure value is reached.

[0069] The transition resistor burnout state can be checked by the following steps:

[0070] If the no-load loss of the transformer is P0 in the large capacity state, the total loss is P D， The total loss of the transition resistor in series with the high and low voltage coils during the transformer capacity adjustment process is P G， The current on the high-voltage side is I, and after converting the low-voltage transition resistance to the high-voltage side, the total resistance of the high- and low-voltage transition resistance is R;

[0071] For the high-voltage coil star-angle conversion type capacity regulating transformer, suppose the direct resistance ratio of the high-voltage coil to the low-voltage coil after the low-voltage coil is converted to the high-voltage side is k, then R is calculated using the following formula:

[0072]

[0073] For high-voltage coil series-parallel conversion type capacity-adjusting transformer, R is calculated using the following formula:

[0074]

[0075] The degree of damage to the transition resistor is directly related to the R value. The degree of burnout of the transition resistor can be determined by judging the difference between R and the normal value.

[0076] Furthermore, this embodiment also provides an online status diagnosis system for an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer, comprising:

[0077] Build a module, deploy the travel switch and detect the travel switch status and the operating coil current curve to determine whether the inherent action time has been exceeded;

[0078] The comparison module analyzes the length of the current change curve of the vacuum tube operating coil, compares the normal and leaking states, and detects the maximum value change of the operating coil power supply circuit current;

[0079] The judgment module monitors the increase in the length of the current change curve of the operating coil power supply circuit, and calculates the transition resistance value based on the total loss, no-load loss and current according to the transformer type to judge the degree of burning;

[0080] Output module, the controller processes diagnostic data in real time, stores and uploads information via 4G / 5G.

[0081] This embodiment also provides a computer device, which is suitable for the case of an online status diagnosis method of an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer, and includes a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute computer-executable instructions to implement the online status diagnosis method of the on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer as proposed in the above embodiment.

[0082] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0083] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer is implemented as proposed in the above embodiment.

[0084] In summary, by installing a travel switch at the large and small capacity positions of the capacitance adjustment switch and combining it with the detection of the operating coil current curve, real-time monitoring of the switch stuck state is achieved. This method can not only determine whether a stuck state has occurred, but also accurately locate the stuck point, which helps to timely discover and solve potential problems and improve the reliability and safety of the system.

[0085] By analyzing the length of the current change curve of the vacuum tube operating coil and comparing the normal and leaking states, accurate diagnosis of the vacuum tube vacuum reduction state is achieved. This non-invasive detection method avoids the tedious process of traditional disassembly inspection, greatly improves diagnostic efficiency, and reduces maintenance costs.

[0086] By monitoring the maximum current change of the operating coil power supply circuit, an early warning of the burning state of the operating coil is achieved. This method can detect problems in time before the coil is seriously damaged, effectively preventing equipment failures caused by coil burning and extending the service life of the equipment.

[0087] By detecting the increase in the length of the current change curve of the operating coil power supply circuit, dynamic monitoring of the capacity loss state of the energy storage capacitor is achieved. This method can accurately evaluate the remaining life of the capacitor, provide a scientific basis for equipment maintenance, and avoid sudden failures caused by capacitor failure.

[0088] According to the transformer type, the transition resistance value is calculated using the total loss, no-load loss and current, realizing a quantitative assessment of the degree of transition resistance burnout. This diagnostic method based on mathematical models improves the accuracy of diagnosis and provides a reliable basis for equipment management decisions.

[0089] By processing diagnostic data in real time through the controller and uploading information via 4G / 5G, remote real-time monitoring and data analysis are realized. This intelligent diagnostic system greatly improves equipment management efficiency, realizes predictive maintenance, and reduces operation and maintenance costs.

[0090] In summary, the online status diagnosis method and system provided by the present invention realizes a comprehensive diagnosis of the key components of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer through multi-dimensional real-time monitoring and intelligent analysis. This innovative diagnostic method not only improves the reliability and safety of the equipment, but also realizes predictive maintenance, greatly reducing maintenance costs and power outage risks. At the same time, the remote monitoring function of the system provides strong support for the intelligent management of the power grid, which is of great significance to improving the operating efficiency and reliability of the entire power system.

[0091] Example 2

[0092] Reference Figure 2 - Figure 8 , which is the second embodiment of the present invention, provides an online status diagnosis method for an on-load capacity-adjusting switch of a permanent magnet mechanism of a transformer. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0093] The following specifically describes the methods for online diagnosis of the stuck state of the on-load capacity regulating switch, the reduced vacuum degree of the vacuum tube, the burned state of the operating coil, the loss state of the energy storage capacitor, and the burned state of the transition resistor.

[0094] The transformer on-load capacity adjustment switch can adjust the transformer to a large capacity or small capacity state. Correspondingly, the capacity adjustment switch has a large capacity position and a small capacity position.

[0095] When the capacity regulating switch is adjusted from the large capacity position to the small capacity position or from the small capacity position to the large capacity position, once it becomes stuck, the normally open travel switches installed at the large capacity position and the small capacity position in the capacity regulating switch will both be in the open state.

[0096] Therefore, the controller of the on-load capacity-adjusting switch determines whether a jam has occurred by detecting whether the travel switches at the large and small capacity positions of the capacity-adjusting switch exceed the inherent action time range of the capacity-adjusting switch after issuing the capacity-adjusting command.

[0097] The characteristic of the permanent magnet mechanism is that the operating coil has a large inductance in the open and closed states, and the inductance is the smallest in the middle position. Therefore, the normal current curve flowing through the operating coil during its operation is Figure 3 , Figure 6 , Figure 7 , Figure 8 The solid line part shows the characteristic of first getting bigger and then getting smaller.

[0098] By detecting the current in the power supply circuit of the capacitance switch operating coil, the position of the sudden change point of the current curve during normal operation can be distinguished. Figure 3 For example, this mutation point occurs 16ms after the coil is powered on. According to the current curve during normal operation, the corresponding stroke measured at the time of switch production in the no-power state, and the corresponding relationship data controller, the controller can determine the stroke position of the switch stagnation point. If the operating circuit current is compared with the normal operating current and there is no abnormality, it can be determined that the travel switch is damaged.

[0099] When the capacity-adjusting switch uses a vacuum tube, when the vacuum degree of the vacuum tube decreases, its self-closing force will also decrease, which will make the corresponding vacuum tube open faster and close slower relative to the normal vacuum degree, thus increasing the length of the current change curve of the power supply circuit of the vacuum tube switch operating coil. By detecting the length of the current change curve of the power supply circuit of the vacuum tube switch operating coil in the capacity-adjusting switch, if the current change curve becomes longer due to the slower speed when the vacuum tube closes, such as Figure 2 The midpoint line and the vacuum tube opening speed become faster and the current change curve becomes shorter. Figure 2 By comparing the length of the current change curve when the vacuum tube is open and closed under the two conditions of normal vacuum tube and complete vacuum tube leakage, the degree of vacuum tube leakage can be determined.

[0100] When the operating coil of the capacitance switch is burned out, it is mostly due to insulation damage first, resulting in a short circuit between turns. A few short circuits between turns develop into a majority of short circuits between turns, until the coil is completely burned out or the current is too large to burn out the relay in the controller that controls the power supply to the coil. When the coil turns are short-circuited, the coil resistance and reactance values ​​will decrease accordingly, and the current flowing through the coil will show an increasing trend, such as Figure 3 Therefore, by detecting the maximum current in the current change curve of the power supply circuit of each operating coil of the capacitance regulating switch, it can be determined whether the operating coil is in a short-circuit burnout state.

[0101] As the energy storage capacitor in the adjustable capacity switch controller increases with the increase of service life, its capacitance will gradually lose and decrease. The decrease in the capacity of the energy storage capacitor will slow down the opening and closing speed of the switch, resulting in a longer opening and closing time, until it will not operate. Therefore, by detecting the length of the current change curve of the power supply circuit of each operating coil in the adjustable capacity switch, if the current change curve of the switch becomes longer during the opening and closing process, it means that the capacitance begins to lose. When the length of the change curve is close to the length of the current change curve corresponding to the minimum drivable operating coil energy storage capacitor, it reaches the capacitor failure value, and the capacitor must be replaced or the entire controller must be replaced.

[0102] The three-phase symmetry of the three-phase capacity regulating transformer is only taken as an example of one phase. Figure 7 This is the A-phase principle diagram of the high-voltage coil star-delta conversion type capacity-adjusting transformer, in which the tail of the high-voltage coil AX can be connected in delta or star, that is, through the capacity-adjusting switch contact 103 or 104, "Y" is connected for star connection, and "D" is connected for delta connection; the low-voltage coil ax is composed of ax1, ax2 and ax3, ax1 and ax2 can be connected in parallel through contacts 203 and 205, and in series through 204; the high-voltage capacity-adjusting transition circuit is composed of transition contact 101 in series with high-voltage transition resistor 102, and the low-voltage capacity-adjusting transition circuit is composed of transition contact 201 in series with low-voltage transition resistor 202. The principle of this capacity-adjusting transformer is: when the capacity is large, the high-voltage winding of the transformer is delta-connected, and the series-parallel parts of the low-voltage winding are connected in parallel to form Dyn 11 Connection method: When the capacity is small, the high-voltage winding of the transformer is star-connected, and the series-parallel part of the low-voltage winding is connected in series Yyn0. When the main contact of the capacity adjustment changes from a large capacity state to a small capacity state, or from a small capacity to a large capacity, the transition circuit is connected to the circuit in advance and exits the circuit after the main contact is adjusted, so as to maintain the power supply continuity during the transformer capacity adjustment process. The transition resistor limits the internal circulation of the transformer during this process.

[0103] When the transformer capacity changes from large to small, the high-voltage coil changes from delta connection to star connection. According to circuit knowledge, the voltage ratio of the high-voltage coil terminal voltage when the capacity is large is 3:1 compared to that when the capacity is small; the turns ratio of the series-parallel part ax1 and ax2 to ax3 on the low-voltage side is (3-1):(2-3). When the series-parallel part ax1 and ax2 are connected in parallel, the turns ratio of the entire low-voltage coil is 1:3 compared to that when they are connected in series. Therefore, the output voltage of the low-voltage side of the transformer remains unchanged after it is adjusted to a small capacity. Since the voltage of a single turn of the transformer coil becomes lower after it is adjusted to a small capacity, the transformer core loss is reduced, thereby reducing the transformer no-load loss and achieving energy saving when the transformer is lightly loaded or no-loaded.

[0104] Figure 7 (a) shows that the capacity-adjusting transformer is in a large capacity state. In the figure, 103, 104, 203, 204, and 205 are all in a small capacity state when they are shifted. Figure 7In the state (b), in this state, the transition circuits 101 and 201 are closed, and 103, 104, 203, 204, and 205 are all disconnected. Because the action time of the capacity adjustment switch is short, it is assumed that the load current converted to the high-voltage side I before, after, and during the capacity adjustment remains unchanged, and the transformer terminal voltage remains unchanged. Compared with (a) and (b), the transition resistance is small, and the impact on the transformer coil terminal voltage is negligible. At this time, the number of turns of the high and low voltage coils connected to the circuit in Figures (a) and (b) remains unchanged. From the transformer knowledge, it can be known that the transformer no-load loss P0 remains unchanged when the number of coil turns and the form of the connected circuit remain unchanged. Figure (a) is the large-capacity state of the transformer, that is, when the large-capacity no-load loss of the transformer is P0, Figure 7 (b) The no-load loss of the transformer in the transient state is also P0. Assume that the ratio of the direct resistance of the high-voltage coil of the transformer to the direct resistance of the low-voltage coil multiplied by the square of the transformer ratio is k:1 after conversion to the high-voltage side. Then the transformer load loss, that is, the ratio of the high-voltage and low-voltage coil losses in the coil loss is also k:1. Assume Figure 7 The total transformer loss in (a) is P D but Figure 7 (a) The losses of medium and low voltage coils are:

[0105]

[0106] The turns ratio of the low-voltage coils ax1, ax2 and ax3 is (3-1): (3-1): (2-3). Since the diameter of each turn of the coils ax1 and ax2 is half of that of ax3, their direct resistance ratio, i.e., the loss ratio when the same current flows through them, is 2*(3-1): 2*(3-1): (2-3). Figure 7 (a) and Figure 7 (b) It can be seen that the total resistance ratio of the low-voltage coil in the two states is 1:3. When the current I flows through the coil part connected to the circuit Figure 7 The loss of state (b) is only increased compared to state 2(a) as shown below:

[0107]

[0108] Assume that the total resistance of the high voltage transition resistor 102 and the low voltage side transition resistor 202 in series after being converted to the high voltage side is R, then Figure 7 The total transformer loss in (b) is P G， According to the above analysis, the following active power balance equation can be listed:

[0109]

[0110] From formula (1), we can get

[0111] Figure 8This is the A-phase circuit diagram of the three-phase capacity-adjusting transformer with high-voltage coil series-parallel conversion. The high-voltage coil of the transformer consists of windings AX1 and AX2, which can be connected in parallel through the capacity-adjusting switch contacts 303 and 305, and in series through 304; the low-voltage coil consists of windings ax1 and ax2, which can be connected in parallel through contacts 403 and 405, and in series through 404; the high-voltage capacity-adjusting transition circuit is composed of a transition contact 301 in series with a high-voltage transition resistor 302, and the low-voltage capacity-adjusting transition circuit is composed of a transition contact 401 in series with a low-voltage transition resistor 402. The principle of this capacity-adjusting transformer is: when the capacity is large, the high-voltage and low-voltage coil windings of the transformer are connected in parallel to form Dyn 11 The connection method is that the three phases of the high voltage coil are connected in delta connection, and the low voltage coil is connected in star connection. When the capacity is small, the high voltage and low voltage coil windings of the transformer are connected in series to form a Dyn 11 Connection method. When the main contact of the capacity adjustment changes from a large capacity state to a small capacity state, or from a small capacity to a large capacity, the transition circuit is connected to the circuit in advance and exits the circuit after the main contact is adjusted, so as to maintain the power supply continuity during the transformer capacity adjustment process. The transition resistor limits the internal circulating current of the transformer during this process.

[0112] The transformer is Dyn for both large and small capacity. 11 The connection method is simple, and because the number of turns of the high and low voltage coils of the transformer becomes twice that of the large capacity after the large capacity is changed to the small capacity, the output voltage on the low voltage side remains unchanged. Since the voltage of the transformer coil per turn becomes 1 / 2 of that of the large capacity after the small capacity is adjusted, the transformer core loss is reduced, thereby reducing the transformer no-load loss and realizing energy saving when the transformer is lightly loaded or no-loaded.

[0113] Figure 8 (a) shows that the capacity-adjusting transformer is in a large capacity state. When 303, 304, 403, 404, and 405 are all in a small capacity state, the capacity-adjusting process needs to go through Figure 8 In the state (b), in this state, transition circuits 301 and 401 are closed, and 303, 304, 403, 404, and 405 are all disconnected. Because the action time of the capacity adjustment switch is short, it is assumed that the load current converted to the high-voltage side I before, after, and during the capacity adjustment remains unchanged, and the transformer terminal voltage remains unchanged. Compared with (a) and (b), due to the small transition resistance, the impact on the transformer coil terminal voltage is negligible. At this time, the number of turns of the high and low voltage coils connected to the circuit in Figures (a) and (b) remains unchanged. From the transformer knowledge, it can be known that the transformer no-load loss P0 remains unchanged when the number of coil turns and the form of the connected circuit remain unchanged. Figure (a) is the large-capacity state of the transformer, that is, when the large-capacity no-load loss of the transformer is P0, Figure 8 (b) The no-load loss of the transformer in the transient state is also P0. Since the diameters of each turn of the coils ax1, ax2 and AX1, AX2 are usually equal, Figure 8 (a) and Figure 8(b) It can be seen that the total resistance ratio of the coil in the two states is 1:2, and the current I remains unchanged Figure 7 The coil loss in state (b) is twice that in state 2 (a). Assuming that the total resistance of the high-voltage transition resistor 302 and the low-voltage side transition resistor 402 in series after being converted to the high-voltage side is R, then Figure 8 The total transformer loss in (b) is P G， According to the above analysis, the following active power balance equation can be listed:

[0114] P G -P0=(P D -P0)×2+I 2 ×R (3)

[0115] From formula (3), we can get

[0116] The degree of damage to the transition resistor is directly related to the R value. The degree of difference between R and the normal value can determine the degree of burnout of the transition resistor. Although there are approximate assumptions in the calculation process of formulas (1) to (4), and the resistance will vary with different temperature values, the normal value of the transition resistor is corrected to the actual value after the rated temperature rise of the transformer and the capacity adjustment under the critical conversion current conditions, and the transition resistor burnout alarm threshold is set to 1.3 to 1.5 times the normal value to avoid judgment errors.

[0117] The above diagnostic method requires the on-off signal of the travel switch at the large and small capacity positions of the capacity regulating switch, so it is necessary to install the travel switch at the large and small capacity positions of the capacity regulating switch; it is necessary to monitor the current of the power supply circuit of each operating coil of the capacity regulating switch, because it is DC, so it is necessary to use a Hall current sensor installed in the above circuit; it is necessary to monitor the real-time active power on the incoming and outgoing sides of the capacity regulating transformer, and the difference is the total loss of the transformer, so it is necessary to install the voltage and current transformers on the incoming and outgoing sides of the capacity regulating transformer; and a controller of the permanent magnet mechanism on-load capacity regulating switch is needed to control the switch. The controller should also have one or more of the above-mentioned online status diagnostic methods, and have the function of storing and uploading diagnostic information through 4G or 5G. Therefore, an online status diagnosis system for an on-load capacity-adjusting switch of a transformer includes one or several online status diagnosis methods of the on-load capacity-adjusting switch; includes a travel switch installed at the large and small capacity positions of the capacity-adjusting switch to implement the above method, a Hall current sensor installed in the power supply circuit of each operating coil of the capacity-adjusting switch, and a voltage and current transformer installed on the incoming and outgoing sides of the capacity-adjusting transformer; includes a controller that can realize the control of the capacity-adjusting switch, online status diagnosis and storage, and upload diagnostic information via 4G or 5G.

[0118] Figure 7 and Figure 8 middle:

[0119] AX: two ends of transformer high-voltage coil AX; a, x: two ends of transformer low-voltage coil ax; X1~X7 are transformer high-voltage coil taps; AX: high-voltage coil; AX1, AX2: windings included in high-voltage coil; ax1, ax2, ax3: windings included in low-voltage coil; 101: high-voltage transition contact of star-angle conversion type capacity regulating switch; 102: high-voltage transition resistor of star-angle conversion type capacity regulating switch; 103: high-voltage angle-connected main contact of star-angle conversion type capacity regulating switch; 104: high-voltage star-connected main contact of star-angle conversion type capacity regulating switch; 201: low-voltage transition contact of star-angle conversion type capacity regulating switch; 202: low-voltage transition resistor of star-angle conversion type capacity regulating switch; 203: low-voltage parallel main contact 1 of star-angle conversion type capacity regulating switch; 204: star-angle conversion type capacity regulating switch Switch low-voltage series main contact; 205: star-angle conversion type regulating switch low-voltage parallel main contact 2; 301: series-parallel conversion type regulating switch high-voltage transition contact; 302: series-parallel conversion type regulating switch high-voltage transition resistor; 303: series-parallel conversion type regulating switch high-voltage parallel main contact 1; 304: series-parallel conversion type regulating switch high-voltage series main contact; 305: series-parallel conversion type regulating switch high-voltage parallel main contact 2; 401: series-parallel conversion type regulating switch low-voltage transition contact; 402: series-parallel conversion type regulating switch low-voltage transition resistor; 403: series-parallel conversion type regulating switch low-voltage parallel main contact 1; 404: series-parallel conversion type regulating switch low-voltage series main contact; 405: series-parallel conversion type regulating switch low-voltage parallel main contact 2.

[0120] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An online state diagnosis method for a transformer permanent magnet mechanism on-load capacity regulating switch, characterized in that: include, Deploy the travel switch and detect the travel switch status and operating coil current curve to determine whether the switch is stuck and the stuck position; Analyze the length of the current change curve of the vacuum tube operating coil, compare the normal and leaking states, and detect the maximum value change of the operating coil power supply circuit current; Monitor the increase in the length of the current change curve of the operating coil power supply circuit. According to the type of transformer, use the total loss, no-load loss and current to calculate the transition resistance value to determine the degree of burnout. The controller processes diagnostic data in real time, stores and uploads the information via 4G / 5G.

2. The online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer according to claim 1 is characterized in that: The travel switch is installed at the large and small capacity positions of the capacitance regulating switch, a Hall current sensor is installed in the operating coil power supply circuit, and a voltage and current transformer is installed on the input and output line sides of the transformer. The online status diagnosis mainly includes the stuck state of the on-load capacitance regulating switch, the reduced vacuum degree of the vacuum tube, the burning state of the operating coil, the loss state of the energy storage capacitor capacity, and the burning state of the transition resistor.

3. The online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer according to claim 2, characterized in that: The determination of the stuck state of the on-load capacity regulating switch includes: The controller detects the status of the travel switch at the large and small capacity positions after the capacity adjustment command is issued to determine whether the inherent action time has been exceeded; Detect the position of the sudden change point of the current in the operating coil power supply circuit to determine the travel position of the switch stagnation point; when there is no abnormality in the operating circuit current but it exceeds the inherent action time, it is judged that the travel switch is damaged.

4. The online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer according to claim 3 is characterized in that: The determination of the vacuum degree reduction state of the vacuum tube includes: detecting the length of the current change curve of the power supply circuit of the vacuum tube operating coil; When the current change curve becomes longer when the switch is closed and becomes shorter when the switch is opened, it is judged that the vacuum degree of the vacuum tube is reduced; The degree of vacuum tube leakage can be determined by comparing the length of the current change curve under normal state and complete leakage state.

5. The online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer according to claim 4, characterized in that: The determination of the burning state of the operating coil includes: Detect the change of the maximum current in the current change curve of the operating coil power supply circuit; when the maximum current exceeds the preset threshold, it is determined that the operating coil is short-circuited and burned.

6. The online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer according to claim 5, characterized in that: The determination of the energy storage capacitor capacity loss state includes: Detect the length of the current change curve of the operating coil power supply circuit; when the current change curve becomes longer during the bidirectional opening and closing of the switch, it is judged that the capacitor capacity begins to lose; When the length of the change curve is close to the length of the current change curve corresponding to the minimum drivable operating coil energy storage capacitor, it is determined that the capacitor failure value has been reached.

7. The online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer according to claim 6, characterized in that: The determination of the burnout state of the transition resistor includes: For the high-voltage coil star-angle conversion type capacity regulating transformer, suppose the direct resistance ratio of the high-voltage coil to the low-voltage coil after the low-voltage coil is converted to the high-voltage side is k, then R is calculated using the following formula: Among them, R is the total resistance of the high-low voltage transition resistor after the high-voltage side, P0 is the no-load loss, P G is the total loss in the transition state, k is the direct resistance ratio of the high and low voltage coils, and I is the current on the high voltage side; For high-voltage coil series-parallel conversion type capacity-adjusting transformer, R is calculated using the following formula: The degree of damage to the transition resistor is directly related to the R value. The degree of burnout of the transition resistor can be determined by judging the difference between R and the normal value.

8. An online state diagnosis system for a transformer permanent magnet mechanism on-load capacity-adjusting switch, based on the online state diagnosis method for a transformer permanent magnet mechanism on-load capacity-adjusting switch according to any one of claims 1 to 7, characterized in that: Also includes, Build a module, deploy the travel switch and detect the travel switch status and the operating coil current curve to determine whether the inherent action time has been exceeded; The comparison module analyzes the length of the current change curve of the vacuum tube operating coil, compares the normal and leaking states, and detects the maximum value change of the operating coil power supply circuit current; The judgment module monitors the increase in the length of the current change curve of the operating coil power supply circuit, and calculates the transition resistance value based on the total loss, no-load loss and current according to the transformer type to judge the degree of burning; Output module, the controller processes diagnostic data in real time, stores and uploads information via 4G / 5G.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the online state diagnosis method of the on-load capacity-adjusting switch of the permanent magnet mechanism of the transformer according to any one of claims 1 to 7 are implemented.

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