Traction transformer fault identification method, system, product, equipment and medium

Abstract

The invention discloses a fault identification method and system for a traction transformer, a product, equipment and a medium, and relates to the field of rail transit traction equipment, and the method comprises the steps: obtaining the secondary side network voltage of the traction transformer and the AC side voltage of a traction converter; the alternating current side of the traction converter is connected with a secondary winding of the traction transformer; determining a state equation corresponding to the traction transformer, wherein the state equation is obtained based on an equivalent circuit of the traction transformer and takes primary side current and secondary side current of the traction transformer as state variables; obtaining a winding current estimation value corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation; and determining an actual state of the traction transformer based on the winding current estimation value and the winding current actual value, wherein the actual state is a fault state or a normal state. Real-time detection, early warning and protection can be achieved in advance in the train running process, the response speed is high, additional sensors are not needed, and the hardware cost of fault detection is reduced.

Description

Technical Field

[0001] The present invention relates to the field of rail transit traction equipment, and particularly to a method, system, product, device and medium for fault identification of a traction transformer. Background Art

[0002] In the field of rail transit traction equipment, a traction transformer is an important part of a train traction system. It converts high-voltage alternating current into lower-voltage alternating current for use by the train traction converter. In actual operation, the traction transformer may have faults such as inter-turn short circuit of the winding and winding grounding. Specifically, it is manifested as a change in the inductance parameter of the transformer body. If the number of shorted turns is large, the current of the transformer may be larger than that in the normal condition when the same power is exerted, and in severe cases, it may cause an overcurrent fault, triggering the protection of the system and affecting the normal use of the train.

[0003] At present, the fault detection of the traction transformer includes off-line detection and on-line detection. Among them, off-line detection is to judge the inter-turn short circuit fault of the transformer by applying certain excitations (such as low-voltage test pulses, frequency sweeping by a frequency sweeper) to the ports of the transformer after the train returns to the depot. This method has a significant lag because it is an off-line method. The off-line troubleshooting and testing are carried out only after the transformer fault has a greater impact on the train operation, and it cannot give early warnings. On-line detection is to detect faults through the vibration signals collected by vibration sensors. This scheme not only requires additional configuration of vibration sensors, but also the law of vibration signals is closely related to the mechanical structure of the train. The test results on one train may not have good universality on other models of trains.

[0004] Therefore, how to provide a solution to the above technical problems is an issue that those skilled in the art need to solve currently. Summary of the Invention

[0005] The object of the present invention is to provide a method, system, product, device and medium for fault identification of a traction transformer, which can perform real-time detection during the train operation, give early warnings and protection in advance, have a fast response speed, do not require additional new sensors, and reduce the hardware cost of fault detection.

[0006] To solve the above technical problems, the present invention provides a method for fault detection of a traction transformer, including:

[0007] Obtain the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter; the AC side of the traction converter is connected to the secondary side winding of the traction transformer, and the secondary side network voltage is obtained by converting according to the primary side network voltage and the voltage ratio of the traction transformer;

[0008] Determine the state equation corresponding to the traction transformer, where the state equation is obtained based on the equivalent circuit of the traction transformer and takes the primary side current and secondary side current of the traction transformer as state variables;

[0009] Obtain the estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage, and the state equation;

[0010] Determine the actual state of the traction transformer based on the estimated value of the winding current and the actual value of the winding current, where the actual state is a fault state or a normal state.

[0011] Optionally, the process of obtaining the AC side voltage of the traction converter includes:

[0012] During the operation of the traction converter, obtain the intermediate DC voltage of the traction converter and the drive signals for controlling each switching tube in the traction converter;

[0013] Calculate the AC side voltage of the traction converter according to the drive signals and the intermediate DC voltage.

[0014] Optionally, the fault detection method for the traction transformer further includes:

[0015] Obtain the equivalent circuit of the traction transformer;

[0016] Determine the mathematical model of the traction transformer according to the equivalent circuit;

[0017] Obtain the state equation taking the primary side current and secondary side current of the traction transformer as state variables based on the mathematical model.

[0018] Optionally, the process of obtaining the equivalent circuit of the traction transformer includes:

[0019] Determine the equivalent type of the traction transformer;

[0020] Determine the equivalent circuit of the traction transformer according to the equivalent type.

[0021] Optionally, the process of obtaining the estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage, and the state equation includes:

[0022] Determine the numerical solution algorithm corresponding to the traction transformer and the solution time step;

[0023] Solve the state equation according to the numerical solution algorithm, the solution time step, the AC side voltage, and the secondary side network voltage to obtain the estimated value of the winding current corresponding to the traction transformer.

[0024] Optionally, the estimated winding current includes the estimated primary current and the estimated secondary current, and the actual winding current includes the actual primary current and the actual secondary current;

[0025] The process of determining the actual state of the traction transformer based on the estimated winding current and the actual winding current includes:

[0026] Obtain the estimated exciting current based on the estimated primary current and the estimated secondary current;

[0027] Obtain the actual exciting current based on the actual primary current and the actual secondary current;

[0028] Determine the actual state of the traction transformer according to the estimated exciting current and the actual exciting current.

[0029] Optionally, the estimated winding current includes the estimated primary current and the estimated secondary current, and the actual winding current includes the actual primary current and the actual secondary current;

[0030] The process of determining the actual state of the traction transformer based on the estimated winding current and the actual winding current includes:

[0031] Obtain the actual primary current of the traction transformer;

[0032] Calculate the primary current difference value between the actual primary current and the estimated primary current;

[0033] Determine whether the primary current difference value is greater than a first preset value;

[0034] If so, determine that the actual state of the traction transformer is the fault state;

[0035] And / or,

[0036] Obtain the actual secondary current of the traction transformer;

[0037] Calculate the secondary current difference value between the actual secondary current and the estimated secondary current;

[0038] Determine whether the secondary current difference value is greater than a second preset value;

[0039] If so, determine that the actual state of the traction transformer is the fault state.

[0040] Optionally, the process of obtaining the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter includes:

[0041] Obtain the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter in the current control period;

[0042] The process of obtaining the estimated value of the winding current corresponding to the traction transformer based on the AC-side voltage, the secondary-side network voltage, and the state equation includes:

[0043] Based on the AC-side voltage, the secondary-side network voltage, and the state equation of the current control period, the estimated value of the primary-side current and the estimated value of the secondary-side current corresponding to the traction transformer are obtained.

[0044] Optionally, the process of obtaining the actual value of the primary-side current of the traction transformer includes:

[0045] Taking the sampled value of the primary-side current of the traction transformer in the current control period as the actual value of the primary-side current of the traction transformer;

[0046] And / or,

[0047] The process of obtaining the actual value of the secondary-side current of the traction transformer includes:

[0048] Taking the sampled value of the secondary-side current of the traction transformer in the current control period as the actual value of the secondary-side current of the traction transformer.

[0049] Optionally, the process of obtaining the actual value of the primary-side current of the traction transformer includes:

[0050] Taking the sampled value of the primary-side current of the traction transformer in the next control period as the actual value of the primary-side current of the traction transformer;

[0051] And / or,

[0052] Taking the sampled value of the secondary-side current of the traction transformer in the next control period as the actual value of the secondary-side current of the traction transformer.

[0053] Optionally, the process of obtaining the actual value of the primary-side current of the traction transformer includes:

[0054] Taking the average value of the sampled value of the primary-side current of the traction transformer in the next control period and the sampled value of the primary-side current of the traction transformer in the current control period as the actual value of the primary-side current of the traction transformer;

[0055] And / or,

[0056] Taking the average value of the sampled value of the secondary-side current of the traction transformer in the next control period and the sampled value of the secondary-side current of the traction transformer in the current control period as the actual value of the secondary-side current of the traction transformer.

[0057] To solve the above technical problems, the present invention also provides a fault detection system for a traction transformer, including:

[0058] A first acquisition module, configured to acquire the secondary side network voltage of a traction transformer and the AC side voltage of a traction converter; the AC side of the traction converter is connected to the secondary side winding of the traction transformer, and the secondary side network voltage is obtained by converting according to the primary side network voltage and the turns ratio of the traction transformer;

[0059] A first determination module, configured to determine a state equation corresponding to the traction transformer, where the state equation is a state equation based on the equivalent circuit of the traction transformer and with the primary side current and the secondary side current of the traction transformer as state variables;

[0060] A first calculation module, configured to obtain an estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage, and the state equation;

[0061] A second determination module, configured to determine the actual state of the traction transformer based on the estimated value of the winding current and the actual value of the winding current, where the actual state is a fault state or a normal state.

[0062] To solve the above technical problems, the present invention also provides a computer program product, including a computer program / instructions, and when the computer program / instructions are executed by a processor, the steps of the fault detection method of the traction transformer described in any one of the above are implemented.

[0063] To solve the above technical problems, the present invention also provides an electronic device, including:

[0064] A memory, configured to store a computer program;

[0065] A processor, configured to implement the steps of the fault detection method of the traction transformer described in any one of the above when executing the computer program.

[0066] To solve the above technical problems, the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the fault detection method of the traction transformer described in any one of the above are implemented.

[0067] The present invention provides a fault detection method for a traction transformer. During the actual operation of a train, the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter are detected online. The secondary side of the traction transformer and the AC side voltage of the traction converter are substituted into a pre-established state equation with the primary side current and secondary side current of the traction transformer as state variables, and the estimated value of the winding current corresponding to the traction transformer is calculated by solving. Since when a fault occurs in the internal winding of the traction transformer, the current on the winding of the traction transformer will change significantly, therefore, according to whether the estimated value of the winding current of the traction transformer in the normal state matches the actual value of the winding current of the traction transformer, the actual state of the traction transformer can be determined. It is detected in real time during the train operation, with early warning and protection, fast response speed, no need to add additional sensors, and the hardware cost of fault detection is relatively low. The present invention also provides a fault detection system, a computer program product, an electronic device and a computer-readable storage medium for the traction transformer, which have the same beneficial effects as the above-mentioned fault detection method for the traction transformer. Description of the Drawings

[0068] In order to more clearly illustrate the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0069] Figure 1 It is a flowchart of the steps of a fault identification method for a traction transformer provided by the present invention;

[0070] Figure 2 It is a waveform diagram of the actual value and estimated value of the primary side current of a traction transformer in a normal state provided by the present invention;

[0071] Figure 3 It is a waveform diagram of the actual value and estimated value of the secondary side current of a traction transformer in a normal state provided by the present invention;

[0072] Figure 4 It is a waveform diagram of the actual value and estimated value of the primary side current of a traction transformer in a fault state provided by the present invention;

[0073] Figure 5 It is a waveform diagram of the actual value and estimated value of the secondary side current of a traction transformer in a fault state provided by the present invention;

[0074] Figure 6 It is an equivalent circuit diagram of a traction converter provided by the present invention;

[0075] Figure 7Schematic diagram of the line side part of a train traction system provided by the present invention;

[0076] Figure 8 Equivalent circuit diagram of a traction transformer provided by the present invention;

[0077] Figure 9 Structural schematic diagram of a fault identification system for a traction transformer provided by the present invention;

[0078] Figure 10 Structural schematic diagram of an electronic device provided by the present invention;

[0079] Figure 11 Structural schematic diagram of a computer-readable storage medium provided by the present invention. Specific embodiments

[0080] The core of the present invention is to provide a fault identification method, system, product, device and medium for a traction transformer, which can perform real-time detection, early warning and protection during the train operation, has a fast response speed, does not require additional sensors, and reduces the hardware cost of fault detection.

[0081] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0082] In the first aspect, the present invention provides a step flow chart of a fault identification method for a traction transformer. The fault identification method for the traction transformer includes:

[0083] S101: Obtain the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter; the AC side of the traction converter is connected to the secondary side winding of the traction transformer, and the secondary side network voltage is obtained by converting according to the primary side network voltage and the voltage ratio of the traction transformer;

[0084] In this embodiment, in the train traction system, the primary side winding of the traction transformer is connected to the power grid, and the secondary side winding of the traction transformer is connected to the traction converter to convert the power grid voltage into the voltage required by the traction converter for the traction converter to use. Among them, the traction transformer includes a primary side winding and at least one secondary side winding, and the number of secondary side windings is set according to actual engineering needs.

[0085] It can be understood that the secondary network voltage of the traction transformer specifically refers to the grid voltage of the secondary winding of the traction transformer. Both the secondary network voltage and the AC side voltage can be instantaneous values. In this embodiment, the secondary network voltage of the traction transformer and the AC side voltage of the traction converter can be obtained according to the control period, or the secondary network voltage of the traction transformer and the AC side voltage of the traction converter can be obtained after receiving a trigger instruction. In this embodiment, the trigger conditions for obtaining the secondary network voltage of the traction transformer and the AC side voltage of the traction converter are not limited herein.

[0086] S102: Determine the state equation corresponding to the traction transformer. The state equation is a state equation obtained based on the equivalent circuit of the traction transformer and with the primary current and secondary current of the traction transformer as state variables.

[0087] The state equation in this embodiment is a state equation established in advance based on the equivalent circuit of the traction transformer and with the primary current and secondary current of the traction transformer as state variables. This state equation is used to solve the estimated values of the primary current and secondary current of the traction transformer, and the state equation is stored in a preset location. In this embodiment, the state equation can be directly read from the preset location. It can be understood that different structures of the traction transformer correspond to different state equations, which can be established according to the actual equivalent circuit, and are not limited herein in this embodiment.

[0088] S103: Obtain the estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary network voltage, and the state equation.

[0089] In this embodiment, by substituting the AC side voltage and the secondary network voltage into the state equation, the estimated value of the winding current when the traction transformer is in a normal state can be solved. The estimated value of the winding current includes the estimated value of the primary current and the estimated value of the secondary current. The state equation in this embodiment is determined according to the equivalent circuit of the traction transformer and is adapted to the actual working conditions of the traction transformer in the traction system, so that the estimated values of the primary current and secondary current of the traction transformer obtained by estimation are more accurate.

[0090] S104: Determine the actual state of the traction transformer based on the estimated value of the winding current and the actual value of the winding current. The actual state is a fault state or a normal state.

[0091] In this embodiment, considering that when the traction transformer is in a normal state, the waveforms of the actual values and estimated values of the primary current and secondary current of the traction transformer are as shown in Figure 2 and Figure 3 The actual value of the winding current and the estimated value of the winding current are almost exactly the same. When an inter-turn short circuit occurs in the secondary winding or primary winding of the traction transformer, the waveforms of the actual values and estimated values of the primary current and secondary current of the traction transformer are as shown in Figure 4 and Figure 5As shown in the figure, the winding current of the traction transformer will change significantly. By using the difference in the magnitude of this current, it is possible to determine whether a fault has occurred inside the transformer.

[0092] Based on this, in this embodiment, the actual state of the traction transformer can be determined according to the difference between the estimated value of the winding current and the actual value of the winding current. If the estimated value of the winding current and the actual value of the winding current are approximately the same, it is considered that the actual state of the traction transformer is in a normal state. If the estimated value of the winding current and the actual value of the winding current are approximately the same, it is considered that the actual state of the traction transformer is in a normal state. If the difference between the estimated value of the winding current and the actual value of the winding current is too large, it is considered that the actual state of the traction transformer is in a fault state.

[0093] As an alternative embodiment, in order to increase the fault tolerance rate and improve the reliability of the fault identification result, this embodiment can detect the duration during which the difference value between the estimated value of the winding current and the actual value of the winding current is too large. If the duration exceeds the preset time, then the actual state of the traction transformer is determined to be in a normal state at this time. Otherwise, the actual state of the traction transformer is determined to be in a fault state, and an alarm message is generated at this time to prompt the driver to pay attention. Among them, when comparing the actual value of the winding current with the estimated value of the winding current, it can be compared based on instantaneous value, amplitude, effective value, etc., and it can be selected according to the actual engineering needs. This embodiment does not make specific limitations here.

[0094] Of course, in addition to the above fault tolerance mechanism, other fault tolerance schemes can also be adopted, and this embodiment does not make specific limitations here.

[0095] It can be seen that in this embodiment, the present invention provides a method for detecting faults in a traction transformer. During the actual operation of the train, the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter are detected online. The secondary side of the traction transformer and the AC side voltage of the traction converter are substituted into the state equation established in advance with the primary side current and secondary side current of the traction transformer as state variables, and the estimated value of the winding current corresponding to the traction transformer is obtained by solving. Since the current on the winding of the traction transformer will change significantly when a fault occurs in the internal winding of the traction transformer, therefore, the present invention can determine the actual state of the traction transformer according to whether the estimated value of the winding current of the traction transformer in the normal state matches the actual value of the winding current of the traction transformer. It is detected in real time during the operation of the train, with early warning and protection, fast response speed, no need to add additional sensors, and the hardware cost of fault detection is relatively low.

[0096] Based on the above embodiment:

[0097] As an alternative embodiment, the process of obtaining the AC side voltage of the traction converter includes:

[0098] During the operation of the traction converter, obtain the intermediate DC voltage of the traction converter and the drive signals for controlling each switching tube in the traction converter;

[0099] Calculate the AC side voltage of the traction converter according to the drive signals and the intermediate DC voltage.

[0100] Refer to Figure 6 As shown, the process of obtaining the AC side voltage of the traction converter will be described. Figure 6 The equivalent circuit diagram of the single-phase four-quadrant converter is shown. The single-phase four-quadrant converter includes two bridge arms, and each bridge arm includes an upper switching tube and a lower switching tube. Figure 6 The first bridge arm in c1 =u d (P1 - P3);

[0101] Among them, u c1 is the AC side voltage of the traction converter, u d is the intermediate DC voltage, P1 is the drive signal of the upper switching tube T1 of the first bridge arm, and P3 is the drive signal of the upper switching tube T3 of the second bridge arm. It can be understood that during the operation of the traction converter, after obtaining the drive signals of each switching tube, the AC side voltage of the traction converter can be obtained through the above formula, and the AC side voltage is calculated by the TCU (Traction Control Unit), with low cost. Of course, Figure 6 only shows a single-phase, two-level converter. For traction converters with topologies such as three-phase, four-phase, three-level, and five-level, the conversion formula is slightly different, and all are to obtain the AC side voltage by multiplying the intermediate DC voltage by the switching function, and the rest is the same.

[0102] As another optional embodiment, in addition to calculating the AC side voltage by obtaining the drive signals and the intermediate DC voltage of the traction converter, a voltage sensor can also be directly added to directly measure the AC side voltage.

[0103] As an optional embodiment, the fault detection method of the traction transformer further includes:

[0104] Obtain the equivalent circuit of the traction transformer;

[0105] Determine the mathematical model of the traction transformer according to the equivalent circuit;

[0106] Based on the mathematical model, a state equation is obtained with the primary current and secondary current of the traction transformer as state variables.

[0107] In this embodiment, the network side part of the train traction system is as Figure 7 shown. The primary winding of the traction transformer is L1, and there may be multiple secondary windings, denoted as L2, L3,.... During the actual operation of the train, there may be inter-turn short circuits or other types of faults in either the primary winding or the secondary winding. To identify internal faults of the transformer, this embodiment first conducts data modeling for this traction transformer.

[0108] Referring to Figure 7 , taking the single secondary winding as an example, a mathematical model of the traction transformer is established. First, referring to Figure 8 , Figure 8 is the T-equivalent circuit diagram of the traction transformer. Based on this equivalent circuit diagram, the mathematical model of the traction transformer is established as follows:

[0109] ;

[0110] Among them, u m is the excitation voltage source, R m is the excitation resistance, i m is the excitation current, L m is the excitation inductance, R1 is the first equivalent resistance, R2 is the second equivalent resistance, is the first equivalent inductance, is the second equivalent inductance;

[0111] Taking the primary current i1 and the secondary current i g1 as state variables, the state equation of the entire equivalent circuit is obtained and written in the standard form as:

[0112] ;

[0113] Among them, ;

[0114] Among them, u g is the primary side network voltage of the traction transformer The secondary side network voltage converted according to the voltage transformation ratio K of the transformer. The transformation formula is:

[0115] ;

[0116] It can be obtained through the above relevant formulas that the input signals of the mathematical model are the secondary side network voltage u g and the AC side voltage u c1, the former is an external condition that varies with the power supply situation, and the latter is determined by the control signal in real-time control. It can be understood that according to the different current directions, there may be certain differences in the mathematical model of the traction converter.

[0117] As an alternative embodiment, the process of obtaining the equivalent circuit of the traction transformer includes:

[0118] Determine the equivalent type of the traction transformer;

[0119] Determine the equivalent circuit of the traction transformer according to the equivalent type.

[0120] In this embodiment, the equivalent type of the equivalent circuit of the traction transformer can be T-type or type, or other types, which can be selected according to the actual engineering needs and are not limited herein in this embodiment.

[0121] As an alternative embodiment, the process of obtaining the estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage, and the state equation includes:

[0122] Determine the numerical solution algorithm corresponding to the traction transformer and the solution time step;

[0123] Solve the state equation according to the numerical solution algorithm, the solution time step, the AC side voltage, and the secondary side network voltage to obtain the estimated value of the winding current corresponding to the traction transformer.

[0124] In this embodiment, the secondary side network voltage u g of the traction transformer is calculated, as well as the AC side voltage u c1 of the traction converter. Substitute u g and u g as input quantities into to obtain the state equation with i1 and i g1 as state variables, and solve this state equation.

[0125]

[0126]

[0127] First, determine the solution time step, that is, the solution time step in this embodiment, denoted as T s , and then the fourth-order Runge-Kutta algorithm (or other numerical solution methods such as the forward Euler method, the backward Euler method, the trapezoidal method, etc.) can be used for calculation.

[0126] When selecting the numerical solution method, it can be selected according to the current required calculation efficiency and the status of the hardware resources, and no specific limitation is made herein in this embodiment.

[0127] As an alternative embodiment, the estimated value of the winding current includes the estimated value of the primary side current and the estimated value of the secondary side current, and the actual value of the winding current includes the actual value of the primary side current and the actual value of the secondary side current;

[0128] The process of determining the actual state of the traction transformer based on the estimated value and the actual value of the winding current includes:

[0129] Obtain the estimated value of the exciting current based on the estimated value of the primary current and the estimated value of the secondary current;

[0130] Obtain the actual value of the exciting current based on the actual value of the primary current and the actual value of the secondary current;

[0131] Determine the actual state of the traction transformer according to the estimated value and the actual value of the exciting current.

[0132] Referring to the above mathematical model, the exciting current i m can be calculated based on the primary current i1 and the secondary current i g1 When identifying the state of the traction converter, it can also be judged by the difference value between the estimated value and the actual value of the exciting current. The change of the exciting current can sensitively reflect the minor faults inside the transformer, such as winding short circuit, insulation aging, etc., so that the faults can be discovered and processed before they develop into serious problems. Moreover, the exciting current is directly related to the magnetic flux inside the transformer, so it can more accurately reflect the fault situation inside the transformer.

[0133] As an optional embodiment, the estimated value of the winding current includes the estimated value of the primary current and the estimated value of the secondary current, and the actual value of the winding current includes the actual value of the primary current and the actual value of the secondary current;

[0134] The process of determining the actual state of the traction transformer based on the estimated value and the actual value of the winding current includes:

[0135] Obtain the actual value of the primary current of the traction transformer;

[0136] Calculate the primary current difference value between the actual value of the primary current and the estimated value of the primary current;

[0137] Judge whether the primary current difference value is greater than the first preset value;

[0138] If so, determine that the actual state of the traction transformer is a fault state;

[0139] And / or,

[0140] Obtain the actual value of the secondary current of the traction transformer;

[0141] Calculate the secondary current difference value between the actual value of the secondary current and the estimated value of the secondary current;

[0142] Judge whether the secondary current difference value is greater than the second preset value;

[0143] If so, determine that the actual state of the traction transformer is a fault state.

[0144] In this embodiment, the first preset value and the second preset value may be the same or different, and can be selected according to the actual engineering needs. This embodiment does not make specific limitations here.

[0145] As an alternative embodiment, the process of obtaining the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter includes:

[0146] Obtain the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter in the current control period;

[0147] The process of obtaining the estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage, and the state equation includes:

[0148] Obtain the estimated value of the primary side current and the estimated value of the secondary side current corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage in the current control period, and the state equation.

[0149] In this embodiment, the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter can be obtained according to a preset period. Therefore, in this embodiment, the actual state of the traction transformer is detected according to the preset control period, with high reliability, and abnormalities of the traction transformer can be detected in a timely manner.

[0150] In the present invention, when the current control period is reached, the secondary side network voltage of the traction transformer, the AC side voltage of the traction converter, the actual primary side current, and the actual secondary side current can be obtained for subsequent comparison.

[0151] As an alternative embodiment, the process of obtaining the actual value of the primary side current of the traction transformer includes:

[0152] Take the sampled value of the primary side current of the traction transformer in the current control period as the actual value of the primary side current of the traction transformer;

[0153] And / or,

[0154] The process of obtaining the actual value of the secondary side current of the traction transformer includes:

[0155] Take the sampled value of the secondary side current of the traction transformer in the current control period as the actual value of the secondary side current of the traction transformer.

[0156] In this embodiment, the sampled value of the primary side current and the sampled value of the secondary side current in the current control period are respectively used as the actual value of the primary side current and the actual value of the secondary side current, and are compared with the estimated value of the primary side current and the estimated value of the secondary side current calculated in the current control period to determine whether there is a fault in the traction transformer in the current control period, so as to improve the reliability of the recognition result.

[0157] As an alternative embodiment, the process of obtaining the actual value of the primary current of the traction transformer includes:

[0158] Taking the sampled value of the primary current of the traction transformer in the next control period as the actual value of the primary current of the traction transformer;

[0159] And / or,

[0160] Taking the sampled value of the secondary current of the traction transformer in the next control period as the actual value of the secondary current of the traction transformer.

[0161] In this embodiment, the estimated values of the primary current and the secondary current calculated in the current control period are used as the current reference values for the next control period. When the sampled values of the primary current and the secondary current are obtained at the arrival of the (j + 1)-th control period, they are directly compared with the estimated values of the primary current and the secondary current in the j-th control period, so as to identify whether there is a fault in the traction transformer in the (j + 1)-th control period. The identification efficiency is high and it is convenient for early warning in a timely manner.

[0162] As an alternative embodiment, the process of obtaining the actual value of the primary current of the traction transformer includes:

[0163] Taking the average value of the sampled value of the primary current of the traction transformer in the next control period and the sampled value of the primary current of the traction transformer in the current control period as the actual value of the primary current of the traction transformer;

[0164] And / or,

[0165] Taking the average value of the sampled value of the secondary current of the traction transformer in the next control period and the sampled value of the secondary current of the traction transformer in the current control period as the actual value of the secondary current of the traction transformer.

[0166] In this embodiment, the average value can also be obtained by taking the average of the sampled value of the primary current in the j-th control period and the sampled value of the primary current in the (j + 1)-th control period, and then comparing the average value with the estimated value of the primary current calculated in the j-th control period, so as to determine whether there is a fault such as inter-turn short circuit in the primary winding of the transformer in the (j + 1)-th control period. By comparing the average value and the estimated value, the misjudgment caused by the random fluctuation or noise of a single sampled value can be reduced. The average value can smooth the short-term fluctuation and provide an estimate closer to the true value. Comparing with the estimated value can reduce the measurement error, thereby improving the identification accuracy. The fault detection of the secondary side of the traction transformer is the same by analogy.

[0167] In summary, the present invention can be independent of vibration signal monitoring components, gas concentration monitoring components, chromatographic signal monitoring components, temperature monitoring components, etc.; no new electrical quantity sensors are required; it can make real-time judgments during the train operation, give early warnings and protection, and has a fast response speed; it is realized by the TCU through pure software without the cooperation of other hardware, and the engineering application is simple.

[0168] In a second aspect, referring to Figure 9 , the present invention also provides a fault detection system for a traction transformer, including:

[0169] A first acquisition module 11, configured to acquire the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter; the AC side of the traction converter is connected to the secondary side winding of the traction transformer, and the secondary side network voltage is obtained by converting according to the primary side network voltage and the turns ratio of the traction transformer;

[0170] A first determination module 12, configured to determine the state equation corresponding to the traction transformer, where the state equation is a state equation based on the equivalent circuit of the traction transformer and with the primary side current and the secondary side current of the traction transformer as state variables;

[0171] A first calculation module 13, configured to obtain the estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage, and the state equation;

[0172] A second determination module 14, configured to determine the actual state of the traction transformer based on the estimated value of the winding current and the actual value of the winding current, where the actual state is a fault state or a normal state.

[0173] As an optional embodiment, the process of acquiring the AC side voltage of the traction converter includes:

[0174] During the operation of the traction converter, acquire the intermediate DC voltage of the traction converter and the drive signals for controlling each switching tube in the traction converter;

[0175] Calculate the AC side voltage of the traction converter according to the drive signals and the intermediate DC voltage.

[0176] As an optional embodiment, the fault detection system for the traction transformer further includes:

[0177] A second acquisition module, configured to acquire the equivalent circuit of the traction transformer;

[0178] A third determination module, configured to determine the mathematical model of the traction transformer according to the equivalent circuit;

[0179] A second calculation module, configured to obtain a state equation with the primary side current and the secondary side current of the traction transformer as state variables based on the mathematical model.

[0180] As an alternative embodiment, the process of obtaining the equivalent circuit of the traction transformer includes:

[0181] Determine the equivalent type of the traction transformer;

[0182] Determine the equivalent circuit of the traction transformer according to the equivalent type.

[0183] As an alternative embodiment, the process of obtaining the estimated value of the winding current corresponding to the traction transformer based on the AC side voltage, the secondary side network voltage, and the state equation includes:

[0184] Determine the numerical solution algorithm corresponding to the traction transformer and the solution time step;

[0185] Solve the state equation according to the numerical solution algorithm, the solution time step, the AC side voltage, and the secondary side network voltage to obtain the estimated value of the winding current corresponding to the traction transformer.

[0186] As an alternative embodiment, the estimated value of the winding current includes the estimated value of the primary side current and the estimated value of the secondary side current, and the actual value of the winding current includes the actual value of the primary side current and the actual value of the secondary side current;

[0187] The process of determining the actual state of the traction transformer based on the estimated value of the winding current and the actual value of the winding current includes:

[0188] Obtain the estimated value of the exciting current based on the estimated value of the primary side current and the estimated value of the secondary side current;

[0189] Obtain the actual value of the exciting current based on the actual value of the primary side current and the actual value of the secondary side current;

[0190] Determine the actual state of the traction transformer according to the estimated value of the exciting current and the actual value of the exciting current.

[0191] As an alternative embodiment, the estimated value of the winding current includes the estimated value of the primary side current and the estimated value of the secondary side current, and the actual value of the winding current includes the actual value of the primary side current and the actual value of the secondary side current;

[0192] The process of determining the actual state of the traction transformer based on the estimated value of the winding current and the actual value of the winding current includes:

[0193] Obtain the actual value of the primary side current of the traction transformer;

[0194] Calculate the primary side current difference value between the actual value of the primary side current and the estimated value of the primary side current;

[0195] Judge whether the primary side current difference value is greater than the first preset value;

[0196] If so, determine that the actual state of the traction transformer is a fault state;

[0197] and / or

[0198] Obtain the actual value of the secondary side current of the traction transformer;

[0199] Calculate the secondary side current difference value between the actual value of the secondary side current and the estimated value of the secondary side current;

[0200] Determine whether the secondary side current difference value is greater than the second preset value;

[0201] If so, determine that the actual state of the traction transformer is a fault state.

[0202] As an alternative embodiment, the process of obtaining the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter includes:

[0203] Obtain the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter in the current control period;

[0204] The process of obtaining the estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation includes:

[0205] Obtain the estimated value of the primary side current and the estimated value of the secondary side current corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage in the current control period and the state equation.

[0206] As an alternative embodiment, the process of obtaining the actual value of the primary side current of the traction transformer includes:

[0207] Take the sampled value of the primary side current of the traction transformer in the current control period as the actual value of the primary side current of the traction transformer;

[0208] And / or,

[0209] The process of obtaining the actual value of the secondary side current of the traction transformer includes:

[0210] Take the sampled value of the secondary side current of the traction transformer in the current control period as the actual value of the secondary side current of the traction transformer.

[0211] As an alternative embodiment, the process of obtaining the actual value of the primary side current of the traction transformer includes:

[0212] Take the sampled value of the primary side current of the traction transformer in the next control period as the actual value of the primary side current of the traction transformer;

[0213] And / or,

[0214] Take the sampled value of the secondary side current of the traction transformer in the next control period as the actual value of the secondary side current of the traction transformer.

[0215] As an alternative embodiment, the process of obtaining the actual value of the primary side current of the traction transformer includes:

[0216] Use the average value of the sampled primary current of the traction transformer in the next control cycle and the sampled primary current of the traction transformer in the current control cycle as the actual value of the primary current of the traction transformer;

[0217] and / or,

[0218] Use the average value of the sampled secondary current of the traction transformer in the next control cycle and the sampled secondary current of the traction transformer in the current control cycle as the actual value of the secondary current of the traction transformer.

[0219] In a third aspect, the present invention also provides a computer program product, including a computer program / instructions, and when the computer program / instructions are executed by a processor, the steps of the fault detection method of the traction transformer described in any one of the above embodiments are implemented.

[0220] For the introduction of a computer program product provided by the present invention, please refer to the above embodiments, and the present invention will not be elaborated here.

[0221] A computer program product provided by the present invention has the same beneficial effects as the above-mentioned fault detection method of the traction transformer.

[0222] In a fourth aspect, please refer to Figure 10 , the present invention also provides an electronic device, including:

[0223] A memory 21 for storing a computer program;

[0224] A processor 22 for implementing the steps of the fault detection method of the traction transformer described in any one of the above embodiments when executing the computer program.

[0225] The electronic device further includes:

[0226] An input interface 23 connected to the processor 22 via a communication bus 26, for obtaining externally imported computer programs, parameters, and instructions, and storing them in the memory 21 under the control of the processor 22. The input interface can be connected to an input device to receive parameters or instructions manually input by the user. The input device can be a touch layer covered on the display screen, or a button, trackball, or touchpad provided on the terminal housing.

[0227] A display unit 24 connected to the processor 22 via a communication bus 26, for displaying data sent by the processor 22. The display unit can be a liquid crystal display screen or an electronic ink display screen, etc.

[0228] The network port 25 is connected to the processor 22 via the communication bus 26 and is used for communication connection with various external terminal devices. The communication technology adopted for this communication connection can be a wired communication technology or a wireless communication technology, such as Mobile High-Definition Link (MHL) technology, Universal Serial Bus (USB), High-Definition Multimedia Interface (HDMI), Wi-Fi technology, Bluetooth communication technology, Bluetooth Low Energy (BLE) communication technology, communication technology based on IEEE 802.11s, etc.

[0229] For the introduction of an electronic device provided by the present invention, please refer to the above embodiments, and the present invention will not be elaborated herein.

[0230] An electronic device provided by the present invention has the same beneficial effects as the above-mentioned traction transformer fault detection method.

[0231] In the fifth aspect, please refer to Figure 11 , the present invention further provides a computer-readable storage medium 30. A computer program is stored on the computer-readable storage medium 30, and when the computer program is executed by a processor, it implements the steps of the traction transformer fault detection method described in any of the above embodiments.

[0232] The computer-readable storage medium 30 may include: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs.

[0233] For the introduction of a computer-readable storage medium provided by the present invention, please refer to the above embodiments, and the present invention will not be elaborated herein.

[0234] A computer-readable storage medium provided by the present invention has the same beneficial effects as the above-mentioned traction transformer fault detection method.

[0235] It should also be noted that in this specification, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0236] The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting a fault of a traction transformer, characterized in that: include: Acquire the secondary grid voltage of the traction transformer and the AC side voltage of the traction converter; the AC side of the traction converter is connected to the secondary winding of the traction transformer, and the secondary grid voltage is obtained by converting the primary grid voltage and the transformation ratio of the traction transformer; Determine a state equation corresponding to the traction transformer, wherein the state equation is a state equation obtained based on an equivalent circuit of the traction transformer and takes a primary current and a secondary current of the traction transformer as state variables; Obtaining an estimated value of a winding current corresponding to the traction transformer according to the AC side voltage, the secondary grid voltage and the state equation; An actual state of the traction transformer is determined based on the winding current estimation value and the winding current actual value, and the actual state is a fault state or a normal state.

2. The fault detection method for traction transformer according to claim 1, characterized in that: The process of obtaining the AC side voltage of the traction converter includes: During the operation of the traction converter, an intermediate DC voltage of the traction converter and a driving signal for controlling each switch tube in the traction converter are obtained; The AC side voltage of the traction converter is calculated according to the drive signal and the intermediate DC voltage.

3. The fault detection method for traction transformer according to claim 1, characterized in that: The traction transformer fault detection method further includes: Obtaining an equivalent circuit of the traction transformer; Determining a mathematical model of the traction transformer according to the equivalent circuit; Based on the mathematical model, a state equation is obtained with the primary current and the secondary current of the traction transformer as state variables.

4. The fault detection method for traction transformer according to claim 3, characterized in that: The process of obtaining the equivalent circuit of the traction transformer includes: determining an equivalent type of the traction transformer; An equivalent circuit of the traction transformer is determined according to the equivalent type.

5. The method for detecting faults of a traction transformer according to claim 1, characterized in that: The process of obtaining the estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary grid voltage and the state equation includes: Determining a numerical solution algorithm corresponding to the traction transformer and a solution time step; The state equation is solved according to the numerical solution algorithm, the solution time step, the AC side voltage, and the secondary side grid voltage to obtain an estimated value of the corresponding winding current of the traction transformer.

6. The method for detecting faults of a traction transformer according to claim 1, characterized in that: The winding current estimated value includes a primary current estimated value and a secondary current estimated value, and the winding current actual value includes a primary current actual value and a secondary current actual value; The process of determining the actual state of the traction transformer based on the winding current estimation value and the winding current actual value comprises: Obtaining an excitation current estimation value based on the primary current estimation value and the secondary current estimation value; Obtaining an actual value of the excitation current based on the actual value of the primary current and the actual value of the secondary current; The actual state of the traction transformer is determined according to the estimated value of the excitation current and the actual value of the excitation current.

7. The method for detecting faults of a traction transformer according to any one of claims 1 to 6, characterized in that: The winding current estimated value includes a primary current estimated value and a secondary current estimated value, and the winding current actual value includes a primary current actual value and a secondary current actual value; The process of determining the actual state of the traction transformer based on the winding current estimation value and the winding current actual value comprises: Obtaining an actual value of the primary current of the traction transformer; Calculating a primary current difference value between the actual primary current value and the estimated primary current value; Determining whether the primary current difference value is greater than a first preset value; If so, determining that the actual state of the traction transformer is the fault state; and / or, Obtaining an actual value of the secondary current of the traction transformer; Calculating a secondary current difference value between the actual secondary current value and the estimated secondary current value; Determining whether the secondary side current difference value is greater than a second preset value; If so, it is determined that the actual state of the traction transformer is the fault state.

8. The method for detecting faults of a traction transformer according to claim 7, characterized in that: The process of obtaining the secondary grid voltage of the traction transformer and the AC side voltage of the traction converter includes: Obtaining the secondary grid voltage of the traction transformer and the AC side voltage of the traction converter in the current control cycle; The process of obtaining the estimated value of the winding current corresponding to the traction transformer according to the AC side voltage, the secondary grid voltage and the state equation includes: The primary current estimation value and the secondary current estimation value corresponding to the traction transformer are obtained according to the AC side voltage, the secondary grid voltage and the state equation in the current control cycle.

9. The method for detecting faults of a traction transformer according to claim 8, characterized in that: The process of obtaining the actual value of the primary current of the traction transformer includes: Using the primary current sampling value of the traction transformer in the current control cycle as the actual primary current value of the traction transformer; and / or, The process of obtaining the actual value of the secondary current of the traction transformer includes: The secondary current sampling value of the traction transformer in the current control cycle is used as the actual value of the secondary current of the traction transformer.

10. The method for detecting faults of a traction transformer according to claim 8, characterized in that: The process of obtaining the actual value of the primary current of the traction transformer includes: Taking the primary current sampling value of the traction transformer in the next control cycle as the actual value of the primary current of the traction transformer; and / or, The secondary current sampling value of the traction transformer in the next control cycle is used as the actual value of the secondary current of the traction transformer.

11. The method for detecting faults of a traction transformer according to claim 8, characterized in that: The process of obtaining the actual value of the primary current of the traction transformer includes: Taking the average value of the primary current sampling value of the traction transformer in the next control cycle and the primary current sampling value of the traction transformer in the current control cycle as the actual value of the primary current of the traction transformer; and / or, An average value of the secondary current sampling value of the traction transformer in the next control cycle and the secondary current sampling value of the traction transformer in the current control cycle is used as the actual value of the secondary current of the traction transformer.

12. A traction transformer fault detection system, characterized in that: include: The first acquisition module is used to acquire the secondary grid voltage of the traction transformer and the AC side voltage of the traction converter; the AC side of the traction converter is connected to the secondary winding of the traction transformer, and the secondary grid voltage is obtained by converting the primary grid voltage and the transformation ratio of the traction transformer; A first determination module is used to determine a state equation corresponding to the traction transformer, where the state equation is a state equation obtained based on an equivalent circuit of the traction transformer and takes a primary current and a secondary current of the traction transformer as state variables; A first calculation module, used for obtaining an estimated value of a winding current corresponding to the traction transformer according to the AC side voltage, the secondary grid voltage and the state equation; The second determination module is used to determine the actual state of the traction transformer based on the winding current estimation value and the winding current actual value, and the actual state is a fault state or a normal state.

13. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the traction transformer fault detection method as described in any one of claims 1-11 are implemented.

14. An electronic device, characterized in that: include: Memory for storing computer programs; A processor, configured to implement the steps of the traction transformer fault detection method as described in any one of claims 1 to 11 when executing the computer program.

15. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the traction transformer fault detection method according to any one of claims 1 to 11 are implemented.

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