Transformer winding health state on-line monitoring method and system based on branch connection conductance

Abstract

The invention relates to the technical field of transformer fault monitoring, in particular to a transformer winding health state online monitoring method and system based on branching conductance, and the method comprises the steps: determining a T-shaped equivalent circuit of a transformer winding and a branching conductance formula of the T-shaped equivalent circuit; testing the transformer, and drawing a transformer fault severity and branch connection conductance relation curve graph according to a test result; collecting data in the real-time operation process, and determining a branching conductivity value in the real-time operation process according to a branching conductivity formula; the branch connection conductance value is compared with an alarm threshold value and a tripping threshold value for judgment, and the working state of the transformer is determined; and executing corresponding response measures on the transformer according to the working state of the transformer in the real-time operation process. The current state of the transformer is judged by calculating the conductance of the branch and combining the change characteristics of the conductance of the branch in the T-type equivalent circuit of the transformer during the fault, equipment outage detection is not needed, the health condition of the transformer winding can be monitored on line in real time, and the fault development state of the transformer winding can be predicted.

Description

Technical Field

[0001] The present invention relates to the technical field of transformer fault monitoring, and in particular to a method and system for online monitoring of the health status of transformer windings based on branch conductance. Background Art

[0002] The stability and reliability of power equipment operation play a vital role in the development of the power system. It is the core of the power system and accounts for 60% to 70% of the investment in power system engineering projects. Power equipment is the foundation of power supply reliability and an important guarantee for power safety. Once a power equipment fails, it may cause power outages in some areas at the least, or cause large-scale power paralysis at the worst, and even threaten the safety of people's lives and property, causing huge economic losses.

[0003] With the increasing proportion of renewable energy in the power system and the application of a large number of nonlinear power electronic equipment, the operating environment of transformers is becoming more and more complex. When subjected to large current shocks or a large number of harmonics, transformer windings are prone to minor inter-turn short-circuit faults, which are not easily detected by current protection methods and have significant accumulation characteristics. As the fault continues to accumulate, minor inter-turn short-circuit faults will gradually escalate into serious inter-turn short-circuit faults, causing huge economic losses.

[0004] Most existing detection methods for turn-to-turn short-circuit faults require the equipment to be taken out of service and tested offline within a fixed maintenance cycle. Online monitoring methods are easily affected by complex field environments and, due to their low repeatability in field applications, require experienced maintenance personnel to interpret test results, making detection accuracy dependent on their experience. Furthermore, they are unable to quantitatively assess the health of the transformer windings online. Therefore, a highly sensitive and reliable online detection method is urgently needed to address the need for online monitoring of minor turn-to-turn short-circuit faults in transformer windings.

[0005] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method and system for online monitoring of the health status of transformer windings based on branch conductance. The branch conductance is calculated by the voltage and current on both sides of the transformer, and the change characteristics of the branch conductance in the transformer T-type equivalent circuit during a fault are combined. The current state of the transformer winding can be judged without equipment shutdown for detection. The system is immune to the influence of excitation inrush current and can monitor the health status of the transformer winding online in real time and predict its fault development state without adding any measuring equipment.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: a method for online monitoring of the health status of transformer windings based on branch conductance, comprising the following steps:

[0008] Determine a T-type equivalent circuit of the transformer winding and determine a branch conductance formula of the T-type equivalent circuit;

[0009] Test the transformer and draw a curve showing the relationship between transformer fault severity and transformer branch conductance based on the test results;

[0010] Collecting data during the real-time operation of the transformer, and determining the branch conductance value during the real-time operation of the transformer according to the branch conductance formula;

[0011] Comparing the branch conductance value with the alarm threshold and the trip threshold to determine the working state of the transformer during real-time operation;

[0012] According to the working status of the transformer during real-time operation, corresponding response measures are executed on the transformer.

[0013] Furthermore, determining the T-type equivalent circuit of the transformer winding and determining the branch conductance formula of the T-type equivalent circuit includes the following steps:

[0014] Determine the type of transformer and convert the transformer windings into the corresponding T-type equivalent circuit;

[0015] According to the branch conductance of the transformer in a normal state and an internal fault state, based on Kirchhoff's voltage and current law analysis, the circuit equation corresponding to the T-type equivalent circuit is determined, and the branch conductance formula of the T-type equivalent circuit is determined based on the circuit equation.

[0016] Furthermore, the branch conductance G of the transformer when it is in a normal state is T Obtained by the following formula:

[0017] G T =G m

[0018] Among them, G m It represents the excitation conductance of the transformer;

[0019] The transformer is in internal fault state. T Obtained by the following formula:

[0020]

[0021] Among them, G m Represents the transformer's magnetizing conductance, K r, K1 is an intermediate variable, N1 represents the number of turns of the transformer primary coil; N2 represents the number of turns of the transformer secondary coil; N f Indicates the number of turns of the transformer primary side short-circuit fault coil; R 1σ Indicates the transformer primary side leakage circuit, X 1σ represents the primary side leakage reactance of the transformer, and r represents the short-circuit fault resistance.

[0022] Furthermore, the circuit equation corresponding to the T-type equivalent circuit is:

[0023]

[0024] Determine the branch conductance G of the T-type equivalent circuit based on the circuit equation T The formula is:

[0025]

[0026] Among them, Z T1 Indicates the transformer primary side branch impedance; Z T2 Indicates the transformer secondary side branch impedance; Z T Indicates transformer branch impedance; Indicates the phasor value of the transformer primary side voltage; Indicates the phasor value of the transformer secondary voltage; Indicates the phasor value of the primary side current of the transformer; Indicates the secondary side current phasor value; Indicates the differential current phasor value; Y T represents the transformer branch admittance, real represents the transformer branch admittance Y T Take the real part.

[0027] Furthermore, the step of testing the transformer and drawing a curve showing the relationship between transformer fault severity and transformer branch conductance according to the test results includes the following steps:

[0028] Assume that the transformer is in normal working condition and several inter-turn short-circuit working conditions, wherein the several inter-turn short-circuit working conditions at least include the inter-turn short-circuit ratio N f,p The turn-to-turn short circuit conditions are 0.3%, 0.45%, 0.59%, 0.75%, 0.83%, 1.0%, 1.5% and 2.0%;

[0029] The transformer is tested to obtain the branch conductance G corresponding to the transformer in normal working condition and several short-circuit working conditions. T ;

[0030] With the transformer's working state as the horizontal coordinate and the transformer's branch conductance as the vertical coordinate, a coordinate axis is established for the relationship between transformer fault severity and transformer branch conductance.

[0031] The branch conductance G obtained by the test T Plotted on the relational coordinate axis, a curve diagram showing the relationship between transformer fault severity and transformer branch conductance is formed.

[0032] Furthermore, the step of comparing the branch conductance value with the alarm threshold and the trip threshold to determine the working state of the transformer during real-time operation includes the following steps:

[0033] When the branch conductance value of the transformer in real-time operation is lower than the alarm threshold G Tset1 When , it is determined that the transformer is currently in normal working condition;

[0034] When the branch conductance value of the transformer in real-time operation reaches the alarm threshold G Tset1 , and is at the alarm threshold G Tset1 and trip threshold G Tset2 When the transformer is in a minor fault state,

[0035] When the branch conductance value of the transformer in real-time operation reaches the tripping threshold G Tset2 When the transformer is in a serious fault state.

[0036] Furthermore, executing corresponding response measures on the transformer according to the working status of the transformer during real-time operation includes the following steps:

[0037] When it is determined that the transformer is currently in a normal working state, the transformer does not perform response measures;

[0038] When it is determined that the transformer is currently in a minor fault state, the control transformer sends an alarm signal;

[0039] When it is determined that the transformer is currently in a serious fault state, the transformer is controlled to trip directly.

[0040] The present invention also provides an online monitoring system for transformer winding health status based on branch conductance, comprising:

[0041] A circuit confirmation module is used to determine a T-type equivalent circuit of a transformer winding and determine a branch conductance formula of the T-type equivalent circuit;

[0042] An image generation module is used to test the transformer and draw a curve showing the relationship between transformer fault severity and transformer branch conductance based on the test results;

[0043] A real-time acquisition module is used to collect data during the real-time operation of the transformer and determine the branch conductance value during the real-time operation of the transformer according to the branch conductance formula;

[0044] A status detection module is used to compare the branch conductance value with the alarm threshold and the trip threshold to determine the working status of the transformer during real-time operation;

[0045] The action response module is used to execute corresponding response measures on the transformer according to the working status of the transformer during real-time operation.

[0046] Furthermore, determining the T-type equivalent circuit of the transformer winding and determining the branch conductance formula of the T-type equivalent circuit includes the following steps:

[0047] Determine the type of transformer and convert the transformer windings into the corresponding T-type equivalent circuit;

[0048] According to the branch conductance of the transformer in a normal state and an internal fault state, based on Kirchhoff's voltage and current law analysis, the circuit equation corresponding to the T-type equivalent circuit is determined, and the branch conductance formula of the T-type equivalent circuit is determined based on the circuit equation.

[0049] Furthermore, the step of testing the transformer and drawing a curve showing the relationship between transformer fault severity and transformer branch conductance according to the test results includes the following steps:

[0050] Assume that the transformer is in normal working condition and several inter-turn short-circuit working conditions, wherein the several inter-turn short-circuit working conditions at least include the inter-turn short-circuit ratio N f,p The turn-to-turn short circuit conditions are 0.3%, 0.45%, 0.59%, 0.75%, 0.83%, 1.0%, 1.5% and 2.0%;

[0051] Test the transformer to obtain the branch conductance GT corresponding to the transformer in normal working conditions and several short-circuit working conditions;

[0052] With the transformer's working state as the horizontal coordinate and the transformer's branch conductance as the vertical coordinate, a coordinate axis is established for the relationship between transformer fault severity and transformer branch conductance.

[0053] The branch conductance G obtained by the test T Plotted on the relational coordinate axis, a curve diagram showing the relationship between transformer fault severity and transformer branch conductance is formed.

[0054] Furthermore, the step of comparing the branch conductance value with the alarm threshold and the trip threshold to determine the working state of the transformer during real-time operation includes the following steps:

[0055] When the branch conductance value of the transformer in real-time operation is lower than the alarm threshold G Tset1 When , it is determined that the transformer is currently in normal working condition;

[0056] When the branch conductance value of the transformer in real-time operation reaches the alarm threshold G Tset1 , and is at the alarm threshold G Tset1 and trip threshold G Tset2 When the transformer is in a minor fault state,

[0057] When the branch conductance value of the transformer in real-time operation reaches the tripping threshold G Tset2 When the transformer is in a serious fault state.

[0058] Furthermore, executing corresponding response measures on the transformer according to the working status of the transformer during real-time operation includes the following steps:

[0059] When it is determined that the transformer is currently in a normal working state, the transformer does not perform response measures;

[0060] When it is determined that the transformer is currently in a minor fault state, the control transformer sends an alarm signal;

[0061] When it is determined that the transformer is currently in a serious fault state, the transformer is controlled to trip directly.

[0062] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and runnable on the processor. When the processor executes the program, the steps of the online monitoring method for the health status of a transformer winding based on branch conductivity as described in any one of the above items are implemented.

[0063] The present invention also provides a computer-readable storage medium, characterized in that a computer program is stored on the storage medium, and when the computer program is executed by a processor, the steps of the online monitoring method of the health status of the transformer winding based on branch conductivity as described in any one of the above items are implemented.

[0064] The beneficial effects of the present invention are as follows: the present invention provides a basis for realizing online monitoring of short-circuit faults between transformer winding turns by constructing a T-type equivalent circuit of the transformer; when a short-circuit fault occurs between the winding turns, the change in transformer loss causes a change in the branch conductance of the equivalent circuit, thereby realizing accurate monitoring of the health status of the transformer winding, meeting the sensitivity and reliability requirements of online monitoring, and not requiring operation and maintenance personnel to have rich experience to analyze the detection results; meeting the real-time status monitoring requirements of various types of transformers, and is not affected by the operating environment of the transformer, ensuring the accuracy of the real-time monitoring results, and thus responding in a timely manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0066] Figure 1 Schematic diagram of a flow chart of a method for online monitoring of transformer winding health status based on branch conductance in an embodiment of the present invention;

[0067] Figure 2 Schematic diagram of the process of confirming the branch conductance formula of the T-type equivalent circuit in an embodiment of the present invention;

[0068] Figure 3 Schematic diagram of the structure of a T-type equivalent circuit in an embodiment of the present invention;

[0069] Figure 4 Schematic diagram of the process of forming a curve diagram showing the relationship between transformer fault severity and transformer branch conductance according to an embodiment of the present invention;

[0070] Figure 5 A curve diagram showing the relationship between transformer fault severity and transformer branch conductance in an embodiment of the present invention;

[0071] Figure 6 Schematic diagram of the process of determining the working state of a transformer during real-time operation according to an embodiment of the present invention;

[0072] Figure 7 Schematic diagram of the change of branch conductance under different working conditions of the transformer in an embodiment of the present invention;

[0073] Figure 8 A schematic diagram of a process for executing response measures in an embodiment of the present invention;

[0074] Figure 9 Schematic diagram of the structure of the online monitoring system for the health status of transformer windings based on branch conductance in an embodiment of the present invention. DETAILED DESCRIPTION

[0075] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0076] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0077] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0078] like Figures 1 to 8 The online monitoring method for transformer winding health status based on branch conductance shown includes the following steps:

[0079] Determine the T-type equivalent circuit of the transformer winding and determine the branch conductance formula of the T-type equivalent circuit;

[0080] Test the transformer and draw a curve showing the relationship between transformer fault severity and transformer branch conductance based on the test results;

[0081] Collect data during the real-time operation of the transformer and determine the branch conductance value during the real-time operation of the transformer according to the branch conductance formula;

[0082] Compare the branch conductance value with the alarm threshold and trip threshold to determine the working status of the transformer during real-time operation;

[0083] According to the working status of the transformer during real-time operation, corresponding response measures are taken on the transformer.

[0084] The present invention provides a basis for online monitoring of short-circuit faults between transformer winding turns by constructing a T-type equivalent circuit of the transformer. When a short-circuit fault occurs between the winding turns, changes in transformer loss cause changes in the branch conductance of the equivalent circuit to accurately monitor the health status of the transformer winding, meeting the sensitivity and reliability requirements of online monitoring, and not requiring operation and maintenance personnel to have rich experience to interpret the detection results. It meets the real-time status monitoring needs of various types of transformers, is not affected by the operating environment of the transformer, and ensures the accuracy of the real-time monitoring results, thereby enabling timely response.

[0085] The present invention proposes an online monitoring method for the health status of transformer windings based on branch conductance. The relationship between branch admittance and the health status of transformer windings is obtained in conjunction with a finite element simulation model, thereby realizing online monitoring of the health status of transformer windings. Furthermore, the health status of the windings can provide a reference for maintenance arrangements, ensuring the safe and stable operation of the transformer. By accurately calculating branch conductance and combining the changing characteristics of branch conductance in the transformer T-type equivalent circuit, the solution can sensitively detect minor turn-to-turn short-circuit faults in transformer windings without requiring equipment shutdown, thereby improving the continuity and timeliness of monitoring. The solution is immune to the effects of magnetizing inrush currents and can maintain monitoring accuracy even in complex operating environments. By promptly detecting and handling minor turn-to-turn short-circuit faults in transformer windings, the solution helps improve the power supply reliability of the power system and reduce economic losses caused by power equipment failures. The solution is applicable to various operating environments and helps improve the stability and safety of the power system.

[0086] It should be noted that the solution proposed in this embodiment is mainly for detecting minor inter-turn short-circuit faults in the power transformer winding. Since the branch admittance is only related to the structural parameters of the transformer winding and has nothing to do with the operating environment of the transformer, it can be extended to various types of transformers such as converter transformers and busbar transformers. During the implementation of other types of transformers, adaptive adjustments can be made based on the contents proposed in this solution, and it is not limited to this embodiment.

[0087] Based on the above embodiment, determining the T-type equivalent circuit of the transformer winding and determining the branch conductance formula of the T-type equivalent circuit includes the following steps:

[0088] Determine the type of transformer and convert the transformer winding into the corresponding T-type equivalent circuit. The T-type equivalent circuit of the transformer is the basic equivalent circuit of the transformer, and its branch parameters can reflect the internal health status of the transformer. Compared with the impedance form, the use of equivalent circuit branch admittance parameters to reflect the health status of the transformer is clearer and more intuitive. Specifically, the structure of the T-type equivalent circuit can be set to Figure 3 The structural form shown in;

[0089] According to the branch conductance of the transformer in normal state and internal fault state, based on Kirchhoff's voltage and current law analysis, the circuit equation corresponding to the T-type equivalent circuit is determined, and the branch conductance formula of the T-type equivalent circuit is determined based on the circuit equation.

[0090] Analyze the physical structure and electrical characteristics of the transformer, including the configuration of its windings. According to the type and characteristics of the transformer, select a T-type equivalent circuit model to simulate the electrical behavior of the transformer. Convert the actual winding parameters of the transformer into parameters in the equivalent circuit, such as resistance, inductance, capacitance, etc. Analyze the circuit behavior of the transformer in normal state and internal fault state, such as inter-turn short circuit, and then determine the change process of the transformer's branch conductance in these states, thereby determining the corresponding circuit equation and branch conductance formula.

[0091] Based on the above embodiment, the branch conductance G of the transformer in normal state T Obtained by the following formula:

[0092] G T =G m

[0093] Among them, G m Indicates the excitation conductance of the transformer; the excitation conductance is the conductance generated in the transformer winding due to the change of magnetic flux, which is related to the magnetic circuit characteristics of the transformer;

[0094] The branch conductance G of the transformer when it is in internal fault state T Obtained by the following formula:

[0095]

[0096] Among them, G m Represents the transformer's magnetizing conductance, K r , K1 is an intermediate variable, N1 represents the number of turns of the transformer primary coil; N2 represents the number of turns of the transformer secondary coil; N f Indicates the number of turns of the transformer primary side short-circuit fault coil; R 1σ Indicates the transformer primary side leakage circuit, X 1σ represents the primary side leakage reactance of the transformer, and r represents the short-circuit fault resistance.

[0097] Branch conductivity G T It reflects the loss of the transformer. When there is an internal fault in the transformer, such as a turn-to-turn short circuit, the transformer loss will change. Therefore, by comparing the branch conductance of the transformer in normal and fault states, it is possible to qualitatively analyze the branch conductance G in normal and fault states. T The difference between the branch conductance G T As the severity of the fault increases, it is possible to determine whether the transformer has an internal fault, providing a theoretical basis for determining the specific type of fault. Through analysis, it can be found that the transformer branch conductance G under internal fault conditions T Obviously greater than the normal state, the more serious the fault, the greater the G T The bigger.

[0098] Based on the above embodiment, the circuit equation corresponding to the T-type equivalent circuit is:

[0099]

[0100] Determine the branch conductance G of the T-type equivalent circuit based on the circuit equation T The formula is:

[0101]

[0102] Among them, Z T1 Indicates the transformer primary side branch impedance; Z T2 Indicates the transformer secondary side branch impedance; Z T Indicates transformer branch impedance; Indicates the phasor value of the transformer primary side voltage; Indicates the phasor value of the transformer secondary voltage; Indicates the phasor value of the transformer primary side current; Indicates the secondary side current phasor value; Indicates the differential current phasor value; Y T represents the transformer branch admittance, real represents the transformer branch admittance Y T Take the real part.

[0103] When constructing the branch conductance formula of the T-type equivalent circuit of the transformer, it is necessary to determine the circuit equation corresponding to the T-type equivalent circuit based on the structural form and specific parameters of the formed T-type equivalent circuit, and then describe the relationship between the primary and secondary voltages and currents of the transformer. Through the above circuit equation, the branch conductance G of the transformer can be derived. T The formula provides key indicators for subsequent real-time monitoring of transformers. By collecting the voltage and current data of the primary and secondary sides of the transformer in real time, the real-time branch conductance value of the transformer can be calculated, and then the transformer fault can be diagnosed in the subsequent process, and timely response actions can be taken, which helps to prevent and reduce the fault risks of the power system.

[0104] Based on the above embodiment, testing the transformer and drawing a curve diagram of the relationship between transformer fault severity and transformer branch conductance based on the test results includes the following steps:

[0105] Assume that the transformer is in normal working condition and several inter-turn short-circuit working conditions, wherein the several inter-turn short-circuit working conditions at least include the inter-turn short-circuit ratio N f,p The turn-to-turn short circuit conditions are 0.3%, 0.45%, 0.59%, 0.75%, 0.83%, 1.0%, 1.5% and 2.0%;

[0106] The transformer is tested to obtain the branch conductance G corresponding to the transformer in normal working condition and several short-circuit working conditions. T ;

[0107] With the transformer's working state as the horizontal coordinate and the transformer's branch conductance as the vertical coordinate, a coordinate axis is established for the relationship between transformer fault severity and transformer branch conductance.

[0108] The branch conductance G obtained by the test T Plotted on the relational coordinate axis, a curve diagram showing the relationship between transformer fault severity and transformer branch conductance is formed.

[0109] The relationship curve between transformer fault severity and transformer branch conductance is shown in the figure below: Figure 5 As shown in the figure, by simulating the transformer's operating state under normal conditions and inter-turn short-circuit conditions in advance, the transformer's branch conductance G can be measured and recorded under each set condition. T , forming a performance curve that can reflect the different working conditions of the transformer. By observing the changing trend of the curve, the changing relationship between the branch conductance and the severity of the fault can be determined, which provides a theoretical basis for the subsequent setting of specific thresholds for branch conductance. When the corresponding threshold is exceeded, it indicates that the transformer may have a fault, thereby predicting the potential development of the transformer fault and taking preventive measures in time.

[0110] Based on the above embodiment, comparing the branch conductance value with the alarm threshold and the trip threshold to determine the working status of the transformer during real-time operation includes the following steps:

[0111] When the branch conductance value of the transformer in real-time operation is lower than the alarm threshold G Tset1 When , it is determined that the transformer is currently in normal working condition;

[0112] When the branch conductance value of the transformer in real-time operation reaches the alarm threshold G Tset1 , and is at the alarm threshold G Tset1 and trip threshold G Tset2 When the transformer is in a minor fault state,

[0113] When the branch conductance value of the transformer in real-time operation reaches the tripping threshold G Tset2 When the transformer is in a serious fault state.

[0114] Alarm threshold G Tset1 and trip threshold G Tset2 These are two values ​​set manually based on the transformer branch conductivity relationship curve, where the alarm threshold G Tset1 Should be below the trip threshold G Tset2When the real-time voltage and current data of the transformer in the current operating state are collected, the branch conductance G of the T-type equivalent circuit can be substituted. T Calculate in the formula to obtain the real-time branch conductance G of the transformer T , and when the collected branch conductivity value is lower than the alarm threshold G Tset1 When the transformer is in normal working state, it is determined that the transformer is in normal working state. When the transformer fails, the real-time branch conductance G is obtained by taking the transformer no-load closing, closing with 0.5% turn-to-turn short-circuit fault, and 0.5% turn-to-turn short-circuit fault as examples. T Data and alarm threshold G Tset1 and trip threshold G Tset2 The relationship between Figure 7 As shown, according to different image states, the fault type and severity of the transformer can be determined, thereby providing a data basis for whether response measures need to be taken later and ensuring response efficiency and accuracy.

[0115] Based on the above embodiment, according to the working status of the transformer during real-time operation, corresponding response measures are executed on the transformer, including the following steps:

[0116] When the transformer is determined to be in normal working condition, the transformer does not perform any response measures. Although no immediate action is required for a transformer in normal condition, the transformer's operating parameters should continue to be monitored to ensure that the branch conductance remains normal.

[0117] When the transformer is determined to be in a minor fault state, the control transformer sends an alarm signal; the alarm signal should notify maintenance personnel so that they can check the transformer and perform necessary diagnosis;

[0118] When it is determined that the transformer is currently in a serious fault state, the transformer is controlled to trip directly; the tripping operation will cut off the power supply to the transformer to prevent the fault from further spreading and protect the transformer and the connected power system from damage; when the tripping operation occurs, the system should automatically notify maintenance personnel and relevant management personnel so that further action can be taken immediately.

[0119] It should be noted that no matter which response measures are taken, the system should record all relevant operations and events in detail, including time, branch conductance value, response measure type, etc., so as to facilitate regular analysis of relevant data records, identify fault modes, evaluate the effectiveness of response measures, and optimize future monitoring and response strategies; the transformer maintenance plan can also be formulated or adjusted based on the recorded fault events and analysis results; if it is found that the existing threshold settings are inaccurate or inapplicable, the alarm threshold and tripping threshold should be adjusted to improve the response efficiency and accuracy of the system.

[0120] like Figure 9As shown, the present invention also provides an online monitoring system for transformer winding health status based on branch conductance, comprising:

[0121] A circuit confirmation module is used to determine the T-type equivalent circuit of the transformer winding and determine the branch conductance formula of the T-type equivalent circuit;

[0122] An image generation module is used to test the transformer and draw a curve showing the relationship between transformer fault severity and transformer branch conductance based on the test results;

[0123] A real-time acquisition module is used to collect data during the real-time operation of the transformer and determine the branch conductance value during the real-time operation of the transformer according to the branch conductance formula;

[0124] The status detection module is used to compare the branch conductance value with the alarm threshold and trip threshold to determine the working status of the transformer during real-time operation;

[0125] The action response module is used to execute corresponding response measures on the transformer according to the working status of the transformer during real-time operation.

[0126] The present invention provides a basis for online monitoring of short-circuit faults between transformer winding turns by constructing a T-type equivalent circuit of the transformer. When a short-circuit fault occurs between the winding turns, changes in transformer loss cause changes in the branch conductance of the equivalent circuit to accurately monitor the health status of the transformer winding, meeting the sensitivity and reliability requirements of online monitoring, and not requiring operation and maintenance personnel to have rich experience to interpret the detection results. It meets the real-time status monitoring needs of various types of transformers, is not affected by the operating environment of the transformer, and ensures the accuracy of the real-time monitoring results, thereby enabling timely response.

[0127] Based on the above embodiment, determining the T-type equivalent circuit of the transformer winding and determining the branch conductance formula of the T-type equivalent circuit includes the following steps:

[0128] Determine the type of transformer and convert the transformer windings into the corresponding T-type equivalent circuit;

[0129] According to the branch conductance of the transformer in normal state and internal fault state, based on Kirchhoff's voltage and current law analysis, the circuit equation corresponding to the T-type equivalent circuit is determined, and the branch conductance formula of the T-type equivalent circuit is determined based on the circuit equation.

[0130] Analyze the physical structure and electrical characteristics of the transformer, including the configuration of its windings. According to the type and characteristics of the transformer, select a T-type equivalent circuit model to simulate the electrical behavior of the transformer. Convert the actual winding parameters of the transformer into parameters in the equivalent circuit, such as resistance, inductance, capacitance, etc. Analyze the circuit behavior of the transformer in normal state and internal fault state, such as inter-turn short circuit, and then determine the change process of the transformer's branch conductance in these states, thereby determining the corresponding circuit equation and branch conductance formula.

[0131] Specifically, the branch conductance G when the transformer is in normal state T Obtained by the following formula:

[0132] G T =G m

[0133] Among them, G m Indicates the excitation conductance of the transformer; the excitation conductance is the conductance generated in the transformer winding due to the change of magnetic flux, which is related to the magnetic circuit characteristics of the transformer;

[0134] The branch conductance G of the transformer when it is in internal fault state T Obtained by the following formula:

[0135]

[0136] Among them, G m Represents the transformer's magnetizing conductance, K r , K1 is an intermediate variable, N1 represents the number of turns of the transformer primary coil; N2 represents the number of turns of the transformer secondary coil; N f Indicates the number of turns of the transformer primary side short-circuit fault coil; R 1σ Indicates the transformer primary side leakage circuit, X 1σ represents the primary side leakage reactance of the transformer, and r represents the short-circuit fault resistance.

[0137] By comparing the branch conductance of the transformer in normal and fault conditions, the branch conductance G in normal and fault conditions can be qualitatively analyzed. T The difference between the branch conductance G T As the severity of the fault increases, it is possible to determine whether the transformer has an internal fault, providing a theoretical basis for determining the specific type of fault. Through analysis, it can be found that the transformer branch conductance G under internal fault conditions T Obviously greater than the normal state, the more serious the fault, the greater the G T The bigger.

[0138] Based on the above embodiment, the circuit equation corresponding to the T-type equivalent circuit is:

[0139]

[0140] Determine the branch conductance formula G of the T-type equivalent circuit based on the circuit equation T for:

[0141]

[0142] Among them, Z T1 Indicates the transformer primary side branch impedance; Z T2 Indicates the transformer secondary side branch impedance; Z T Indicates transformer branch impedance; Indicates the phasor value of the transformer primary side voltage; Indicates the phasor value of the transformer secondary voltage; Indicates the phasor value of the transformer primary side current; Indicates the secondary side current phasor value; Indicates the differential current phasor value; Y T represents the transformer branch admittance, real represents the transformer branch admittance Y T Take the real part.

[0143] When constructing the branch conductance formula of the T-type equivalent circuit of the transformer, it is necessary to determine the circuit equation corresponding to the T-type equivalent circuit based on the structural form and specific parameters of the formed T-type equivalent circuit, and then describe the relationship between the primary and secondary voltages and currents of the transformer. Through the above circuit equation, the branch conductance G of the transformer can be derived. T The formula provides key indicators for subsequent real-time monitoring of transformers. By collecting the voltage and current data of the primary and secondary sides of the transformer in real time, the real-time branch conductance value of the transformer can be calculated, and then the transformer fault can be diagnosed in the subsequent process, and timely response actions can be taken, which helps to prevent and reduce the fault risks of the power system.

[0144] Based on the above embodiment, testing the transformer and drawing a curve diagram of the relationship between transformer fault severity and transformer branch conductance based on the test results includes the following steps:

[0145] Assume that the transformer is in normal working condition and several inter-turn short-circuit working conditions, wherein the several inter-turn short-circuit working conditions at least include the inter-turn short-circuit ratio N f,p The turn-to-turn short circuit conditions are 0.3%, 0.45%, 0.59%, 0.75%, 0.83%, 1.0%, 1.5% and 2.0%;

[0146] Test the transformer to obtain the branch conductance GT corresponding to the transformer in normal working conditions and several short-circuit working conditions;

[0147] With the transformer's working state as the horizontal coordinate and the transformer's branch conductance as the vertical coordinate, a coordinate axis is established for the relationship between transformer fault severity and transformer branch conductance.

[0148] The branch conductance GT obtained from the test is plotted on the relational coordinate axis to form a curve showing the relationship between transformer fault severity and transformer branch conductance.

[0149] By simulating the transformer's normal operating state and inter-turn short-circuit operating state in advance, the transformer's branch conductance G can be measured and recorded under each set operating condition. T , forming a performance curve that can reflect the different working conditions of the transformer. By observing the changing trend of the curve, the changing relationship between the branch conductance and the severity of the fault can be determined, which provides a theoretical basis for the subsequent setting of specific thresholds for branch conductance. When the corresponding threshold is exceeded, it indicates that the transformer may have a fault, thereby predicting the potential development of the transformer fault and taking preventive measures in time.

[0150] Based on the above embodiment, comparing the branch conductance value with the alarm threshold and the trip threshold to determine the working status of the transformer during real-time operation includes the following steps:

[0151] When the branch conductance value of the transformer in real-time operation is lower than the alarm threshold G Tset1 When , it is determined that the transformer is currently in normal working condition;

[0152] When the branch conductance value of the transformer in real-time operation reaches the alarm threshold G Tset1 , and is at the alarm threshold G Tset1 and trip threshold G Tset2 When the transformer is in a minor fault state,

[0153] When the branch conductance value of the transformer in real-time operation reaches the tripping threshold G Tset2 When the transformer is in a serious fault state.

[0154] Alarm threshold G Tset1 and trip threshold G Tset2 These are two values ​​set manually based on the transformer branch conductivity relationship curve, where the alarm threshold G Tset1 Should be below the trip threshold G Tset2 When the real-time voltage and current data of the transformer in the current operating state are collected, the branch conductance G of the T-type equivalent circuit can be substituted. T Calculate in the formula to obtain the real-time branch conductance G of the transformer T , and when the collected branch conductivity value is lower than the alarm threshold G Tset1When the transformer is in normal working state, it is determined that the transformer is in normal working state. When the transformer fails, the real-time branch conductance G is obtained by taking the transformer no-load closing, closing with 0.5% turn-to-turn short-circuit fault, and 0.5% turn-to-turn short-circuit fault as examples. T Data and alarm threshold G Tset1 and trip threshold G Tset2 The relationship between Figure 7 As shown, according to different image states, the fault type and severity of the transformer can be determined, thereby providing a data basis for whether response measures need to be taken later and ensuring response efficiency and accuracy.

[0155] Based on the above embodiment, according to the working status of the transformer during real-time operation, corresponding response measures are executed on the transformer, including the following steps:

[0156] When the transformer is determined to be in normal working condition, the transformer does not perform any response measures. Although no immediate action is required for a transformer in normal condition, the transformer's operating parameters should continue to be monitored to ensure that the branch conductance remains normal.

[0157] When the transformer is determined to be in a minor fault state, the control transformer sends an alarm signal; the alarm signal should notify maintenance personnel so that they can check the transformer and perform necessary diagnosis;

[0158] When it is determined that the transformer is currently in a serious fault state, the transformer is controlled to trip directly; the tripping operation will cut off the power supply to the transformer to prevent the fault from further spreading and protect the transformer and the connected power system from damage; when the tripping operation occurs, the system should automatically notify maintenance personnel and relevant management personnel so that further action can be taken immediately.

[0159] It should be noted that no matter which response measures are taken, the system should record all relevant operations and events in detail, including time, branch conductance value, response measure type, etc., so as to facilitate regular analysis of relevant data records, identify fault modes, evaluate the effectiveness of response measures, and optimize future monitoring and response strategies; the transformer maintenance plan can also be formulated or adjusted based on the recorded fault events and analysis results; if it is found that the existing threshold settings are inaccurate or inapplicable, the alarm threshold and tripping threshold should be adjusted to improve the response efficiency and accuracy of the system.

[0160] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor and the memory are connected to a communication bus via a communication interface, thereby completing communication between them. When the processor executes the program, the steps of the online monitoring method for the health status of a transformer winding based on branch conductance as described above are implemented, including determining a T-type equivalent circuit of the transformer winding and determining a branch conductance formula of the T-type equivalent circuit; testing the transformer and drawing a curve diagram of the relationship between the transformer fault severity and the transformer branch conductance according to the test results; collecting data during the real-time operation of the transformer and analyzing the results according to the test results. The branch conductance formula determines the branch conductance value of the transformer during real-time operation; the branch conductance value is compared with the alarm threshold and trip threshold to determine the working status of the transformer during real-time operation; according to the working status of the transformer during real-time operation, corresponding response measures are taken for the transformer; the branch conductance is calculated by the voltage and current electrical quantities on both sides of the transformer, and combined with the change characteristics of the branch conductance in the T-type equivalent circuit of the transformer during fault, the current status of the transformer can be judged without equipment shutdown for detection, and it is immune to the influence of excitation inrush current. Without adding any measuring equipment, the health status of the transformer winding can be monitored online in real time and its fault development status can be predicted.

[0161] The present invention also provides a computer-readable storage medium, characterized in that a computer program is stored on the storage medium, and the storage medium can be sold or used as an independent product. The storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the online monitoring method for the health status of a transformer winding based on branch conductance as described above are implemented, including determining a T-type equivalent circuit of the transformer winding and determining a branch conductance formula of the T-type equivalent circuit; testing the transformer and drawing a relationship curve between the transformer fault severity and the transformer branch conductance according to the test results; collecting data during the real-time operation of the transformer, and determining the branch conductance formula according to the branch conductance formula; The branch conductance formula determines the branch conductance value during the real-time operation of the transformer; the branch conductance value is compared with the alarm threshold and trip threshold to determine the working status of the transformer during real-time operation; according to the working status of the transformer during real-time operation, corresponding response measures are taken for the transformer; the branch conductance is calculated by the voltage and current electrical quantities on both sides of the transformer, and combined with the change characteristics of the branch conductance in the T-type equivalent circuit of the transformer during fault, the current status of the transformer can be judged without equipment shutdown for detection, and it is immune to the influence of excitation inrush current. Without adding any measuring equipment, the health status of the transformer winding can be monitored online in real time and its fault development status can be predicted.

[0162] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0163] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0164] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0165] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0166] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0167] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for online monitoring of transformer winding health status based on branch conductance, characterized in that: The following steps are involved: Determine a T-type equivalent circuit of a transformer winding, and determine a branch conductance formula of the T-type equivalent circuit; Test the transformer and draw a curve showing the relationship between transformer fault severity and transformer branch conductance based on the test results; Collecting data during the real-time operation of the transformer, and determining the branch conductance value during the real-time operation of the transformer according to the branch conductance formula; The branch connection conductivity value is compared with the alarm threshold and the tripping threshold to determine the working state of the transformer during real-time operation; According to the working status of the transformer during real-time operation, corresponding response measures are executed on the transformer.

2. The method for online monitoring of transformer winding health status based on branch conductance according to claim 1 is characterized in that: The method of determining a T-type equivalent circuit of a transformer winding and determining a branch conductance formula of the T-type equivalent circuit comprises the following steps: Determine the type of transformer and convert the transformer windings into the corresponding T-type equivalent circuit; According to the branch conductance of the transformer in a normal state and an internal fault state, based on Kirchhoff's voltage and current law analysis, the circuit equation corresponding to the T-type equivalent circuit is determined, and the branch conductance formula of the T-type equivalent circuit is determined based on the circuit equation.

3. The method for online monitoring of transformer winding health status based on branch conductance according to claim 2 is characterized in that: The branch conductance G when the transformer is in normal state T Obtained by the following formula: G T =G m Among them, G m It represents the excitation conductance of the transformer; The transformer is in an internal fault state. T Obtained by the following formula: Among them, G m Represents the transformer's magnetizing conductance, K r , K1 is an intermediate variable, N1 represents the number of turns of the primary coil of the transformer; N2 represents the number of turns of the secondary coil of the transformer; N f Indicates the number of turns of the transformer primary side short-circuit fault coil; R 1σ Indicates the transformer primary leakage circuit, X 1σ represents the primary side leakage reactance of the transformer, and r represents the short-circuit fault resistance.

4. The method for online monitoring of transformer winding health status based on branch conductance according to claim 3 is characterized in that: The circuit equation corresponding to the T-type equivalent circuit is: Determine the branch conductance G of the T-type equivalent circuit according to the circuit equation T The formula is: Among them, Z T1 Indicates the transformer primary side branch impedance; Z T2 Indicates the transformer secondary side branch impedance; Z T Indicates transformer branch impedance; Indicates the voltage phasor value of the primary side of the transformer; Indicates the voltage phasor value on the secondary side of the transformer; Indicates the current phasor value of the primary side of the transformer; Indicates the secondary side current phasor value; Indicates the differential current phasor value; Y T represents the transformer branch admittance, real represents the transformer branch admittance Y T Take the real part.

5. The method for online monitoring of transformer winding health status based on branch conductance according to claim 1 is characterized in that: The step of testing the transformer and drawing a curve diagram showing the relationship between transformer fault severity and transformer branch conductance according to the test results comprises the following steps: The transformer is assumed to be in normal working condition and several inter-turn short-circuit working conditions, wherein the several inter-turn short-circuit working conditions at least include the inter-turn short-circuit ratio N f,p The turn-to-turn short circuit conditions are 0.3%, 0.45%, 0.59%, 0.75%, 0.83%, 1.0%, 1.5% and 2.0%; The transformer is tested to obtain the branch conductance G corresponding to the transformer in normal working condition and several short-circuit working conditions. T ; With the transformer's working state as the horizontal coordinate and the transformer's branch conductance as the vertical coordinate, a coordinate axis of the relationship between the transformer's fault severity and the transformer's branch conductance is established; The branch conductance G obtained by the test T It is plotted in the relational coordinate axis to form a curve diagram of the relation between transformer fault severity and transformer branch conductance.

6. The method for online monitoring of transformer winding health status based on branch conductance according to claim 1 is characterized in that: Comparing the branch connection conductivity value with the alarm threshold and the tripping threshold to determine the working state of the transformer during real-time operation includes the following steps: When the branch conductivity value of the transformer in real-time operation is lower than the alarm threshold G Tset1 When , it is determined that the transformer is currently in normal working condition; When the branch connection conductivity value of the transformer reaches the alarm threshold G during real-time operation Tset1 , and is at the alarm threshold G Tset1 and trip threshold G Tset2 When the transformer is in the state of minor fault, When the branch connection conductivity value of the transformer in real-time operation reaches the tripping threshold G Tset2 When the transformer is in a serious fault state.

7. The method for online monitoring of transformer winding health status based on branch conductance according to claim 6 is characterized in that: The step of executing corresponding response measures on the transformer according to the working state of the transformer in the real-time operation process comprises the following steps: When it is determined that the transformer is currently in a normal working state, the transformer does not perform response measures; When it is determined that the transformer is currently in a minor fault state, the control transformer sends an alarm signal; When it is determined that the transformer is currently in a serious fault state, the transformer is controlled to trip directly.

8. An online monitoring system for transformer winding health status based on branch conductance, characterized in that: include: A circuit confirmation module, used to determine a T-type equivalent circuit of a transformer winding and determine a branch conductance formula of the T-type equivalent circuit; An image generation module is used to test the transformer and draw a curve diagram showing the relationship between transformer fault severity and transformer branch conductance according to the test results; A real-time acquisition module is used to collect data during the real-time operation of the transformer, and determine the branch conductance value during the real-time operation of the transformer according to the branch conductance formula; A state detection module is used to compare the branch connection conductivity value with the alarm threshold and the tripping threshold to determine the working state of the transformer during real-time operation; The action response module is used to execute corresponding response measures on the transformer according to the working status of the transformer during real-time operation.

9. The transformer winding health status online monitoring system based on branch conductance according to claim 8 is characterized in that: The method of determining a T-type equivalent circuit of a transformer winding and determining a branch conductance formula of the T-type equivalent circuit comprises the following steps: Determine the type of transformer and convert the transformer windings into the corresponding T-type equivalent circuit; According to the branch conductance of the transformer in a normal state and an internal fault state, based on Kirchhoff's voltage and current law analysis, the circuit equation corresponding to the T-type equivalent circuit is determined, and the branch conductance formula of the T-type equivalent circuit is determined based on the circuit equation.

10. The transformer winding health status online monitoring system based on branch conductance according to claim 8, characterized in that: The step of testing the transformer and drawing a curve diagram showing the relationship between transformer fault severity and transformer branch conductance according to the test results comprises the following steps: The transformer is assumed to be in normal working condition and several inter-turn short-circuit working conditions, wherein the several inter-turn short-circuit working conditions at least include the inter-turn short-circuit ratio N f,p The turn-to-turn short circuit conditions are 0.3%, 0.45%, 0.59%, 0.75%, 0.83%, 1.0%, 1.5% and 2.0%; Test the transformer to obtain the branch conductance GT corresponding to the transformer in normal working condition and several short-circuit working conditions; With the transformer's working state as the horizontal coordinate and the transformer's branch conductance as the vertical coordinate, a coordinate axis of the relationship between the transformer's fault severity and the transformer's branch conductance is established; The branch conductance GT obtained by the test is plotted on the relational coordinate axis to form a curve diagram showing the relation between transformer fault severity and transformer branch conductance.

11. The transformer winding health status online monitoring system based on branch conductance according to claim 8 is characterized in that: The step of comparing the branch connection conductivity value with the alarm threshold and the tripping threshold to determine the working state of the transformer during real-time operation comprises the following steps: When the branch conductivity value of the transformer in real-time operation is lower than the alarm threshold G Tset1 When , it is determined that the transformer is currently in normal working condition; When the branch connection conductivity value of the transformer reaches the alarm threshold G during real-time operation Tset1 , and is at the alarm threshold G Tset1 and trip threshold G Tset2 When the transformer is in the state of minor fault, When the branch connection conductivity value of the transformer in real-time operation reaches the tripping threshold G Tset2 When the transformer is in a serious fault state.

12. The transformer winding health status online monitoring system based on branch conductance according to claim 11 is characterized in that: The step of executing corresponding response measures on the transformer according to the working state of the transformer in the real-time operation process comprises the following steps: When it is determined that the transformer is currently in a normal working state, the transformer does not perform response measures; When it is determined that the transformer is currently in a minor fault state, the control transformer sends an alarm signal; When it is determined that the transformer is currently in a serious fault state, the transformer is controlled to trip directly.

13. An electronic device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the method for online monitoring the health status of transformer windings based on branch conductance as described in any one of claims 1 to 7 are implemented.

14. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by the processor, the steps of the method for online monitoring of the health status of transformer windings based on branch conductance as described in any one of claims 1 to 7 are implemented.

Images