Fault identification method and system for traction transformer, product, device, and medium

Abstract

A fault identification method and system for a traction transformer, a product, a device, and a medium, relating to the field of rail transit traction equipment. The method comprises: acquiring a secondary-side grid voltage of a traction transformer and an alternating current-side voltage of a traction converter, wherein the alternating current side of the traction converter is connected to a secondary winding of the traction transformer; determining a state equation corresponding to the traction transformer, wherein the state equation is a state equation obtained on the basis of an equivalent circuit of the traction transformer and takes a primary-side current and a secondary-side current of the traction transformer as state variables; on the basis of the alternating current-side voltage, the secondary-side grid voltage, and the state equation, obtaining an estimated winding current value corresponding to the traction transformer; and determining an actual state of the traction transformer on the basis of the estimated winding current value and an actual winding current value, wherein the actual state is a fault state or a normal state. The present invention can achieve real-time detection, early warning and protection during train operation, has high response speed, and does not require additional sensors, thereby reducing hardware costs of fault detection.

Description

Fault identification method, system, product, equipment and medium of traction transformer TECHNICAL FIELD

[0001] The present application relates to the field of rail transit traction equipment, in particular to a fault identification method, system, product, equipment and medium of traction transformer. BACKGROUND

[0002] In the field of rail transit traction equipment, the traction transformer is an important part of the train traction system, which converts high-voltage alternating current into low-voltage alternating current for the train traction converter. In actual use, the traction transformer may have winding inter-turn short circuit, winding ground fault, etc. Its specific performance is the change of the inductance parameter of the transformer body. If the number of short-circuit turns is large, the current of the transformer may be larger than that in normal working condition under the same power, 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] Currently, the fault detection of the traction transformer includes offline detection and online detection. The offline detection is to apply a certain excitation (such as a low-voltage test pulse, a frequency sweep of a frequency sweeper) to the port of the transformer after the train returns to the garage to determine the inter-turn short circuit fault of the transformer. This method has a significant lag because it is offline. The train operation is greatly affected by the transformer fault, so offline troubleshooting and testing are carried out, which cannot provide timely early warning. The online detection is to detect faults through vibration signals collected by vibration sensors. This scheme requires additional vibration sensors, and the vibration signal is closely related to the mechanical structure of the train. The test results on one train may not be well applicable to other types of trains.

[0004] Therefore, how to provide a solution to the above technical problems is a problem that those skilled in the art need to solve at present.

[0005] SUMMARY

[0006] The purpose of the present application is to provide a fault identification method, system, product, equipment and medium of traction transformer, which can detect in real time during train operation, provide early warning and protection, respond quickly, does not require additional sensors, and reduces the hardware cost of fault detection.

[0007] To solve the above technical problems, the present application provides a fault detection method of traction transformer, comprising:

[0008] obtaining the secondary side network voltage of the traction transformer and the alternating current side voltage of the traction converter; the alternating current side of the traction converter is connected with the secondary side winding of the traction transformer, and the secondary side network voltage is calculated according to the primary side network voltage of the traction transformer and the transformation ratio;

[0009] determining a state equation corresponding to the traction transformer, the state equation being a state equation obtained based on an equivalent circuit of the traction transformer and taking the primary current and the secondary current of the traction transformer as state variables;

[0010] obtaining an estimated winding current value corresponding to the traction transformer according to the AC side voltage, the secondary network voltage and the state equation;

[0011] determining an actual state of the traction transformer based on the estimated winding current value and an actual winding current value, the actual state being a fault state or a normal state.

[0012] Optionally, the process of obtaining the AC side voltage of the traction converter comprises:

[0013] during operation of the traction converter, obtaining an intermediate DC voltage of the traction converter and a driving signal used for controlling each switch tube in the traction converter;

[0014] calculating the AC side voltage of the traction converter according to the driving signal and the intermediate DC voltage.

[0015] Optionally, the fault detection method of the traction transformer further comprises:

[0016] obtaining an equivalent circuit of the traction transformer;

[0017] determining a mathematical model of the traction transformer according to the equivalent circuit;

[0018] obtaining a state equation taking the primary current and the secondary current of the traction transformer as state variables based on the mathematical model.

[0019] Optionally, the process of obtaining the equivalent circuit of the traction transformer comprises:

[0020] determining an equivalent type of the traction transformer;

[0021] determining the equivalent circuit of the traction transformer according to the equivalent type.

[0022] Optionally, the process of obtaining the estimated winding current value corresponding to the traction transformer according to the AC side voltage, the secondary network voltage and the state equation comprises:

[0023] determining a numerical solution algorithm corresponding to the traction transformer and a solution time step;

[0024] solving the state equation according to the numerical solution algorithm, the solution time step, the AC side voltage and the secondary network voltage to obtain the estimated winding current value corresponding to the traction transformer.

[0025] Optionally, the winding current estimation value comprises a primary side current estimation value and a secondary side current estimation value, and the winding current actual value comprises a primary side current actual value and a secondary side current actual value;

[0026] 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:

[0027] The excitation current estimation value is obtained based on the primary side current estimation value and the secondary side current estimation value;

[0028] The excitation current actual value is obtained based on the primary side current actual value and the secondary side current actual value;

[0029] The actual state of the traction transformer is determined according to the excitation current estimation value and the excitation current actual value.

[0030] Optionally, the winding current estimation value comprises a primary side current estimation value and a secondary side current estimation value, and the winding current actual value comprises a primary side current actual value and a secondary side current actual value;

[0031] 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:

[0032] The primary side current actual value of the traction transformer is obtained;

[0033] The primary side current difference value of the primary side current actual value and the primary side current estimation value is calculated;

[0034] It is judged whether the primary side current difference value is greater than a first preset value;

[0035] If yes, it is determined that the actual state of the traction transformer is the fault state;

[0036] and / or,

[0037] The secondary side current actual value of the traction transformer is obtained;

[0038] The secondary side current difference value of the secondary side current actual value and the secondary side current estimation value is calculated;

[0039] It is judged whether the secondary side current difference value is greater than a second preset value;

[0040] If yes, it is determined that the actual state of the traction transformer is the fault state.

[0041] Optionally, the process of obtaining the secondary side network voltage of the traction transformer and the alternating current side voltage of the traction current converter comprises:

[0042] obtaining a secondary side network voltage of the traction transformer and an AC side voltage of the traction converter in a current control period;

[0043] obtaining the estimated winding current value of the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation comprises:

[0044] obtaining the estimated primary side current value and the estimated secondary side current value of the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation in the current control period.

[0045] Optionally, the process of obtaining the actual primary side current value of the traction transformer comprises:

[0046] taking the primary side current sampling value of the traction transformer in the current control period as the actual primary side current value of the traction transformer;

[0047] and / or,

[0048] the process of obtaining the actual secondary side current value of the traction transformer comprises:

[0049] taking the secondary side current sampling value of the traction transformer in the current control period as the actual secondary side current value of the traction transformer.

[0050] Optionally, the process of obtaining the actual primary side current value of the traction transformer comprises:

[0051] taking the primary side current sampling value of the traction transformer in the next control period as the actual primary side current value of the traction transformer;

[0052] and / or,

[0053] taking the secondary side current sampling value of the traction transformer in the next control period as the actual secondary side current value of the traction transformer.

[0054] Optionally, the process of obtaining the actual primary side current value of the traction transformer comprises:

[0055] taking an average of the primary side current sampling value of the traction transformer in the next control period and the primary side current sampling value of the traction transformer in the current control period as the actual primary side current value of the traction transformer;

[0056] and / or,

[0057] taking an average of the secondary side current sampling value of the traction transformer in the next control period and the secondary side current sampling value of the traction transformer in the current control period as the actual secondary side current value of the traction transformer.

[0058] To solve the above technical problems, the application further provides a fault detection system of a traction transformer, comprising:

[0059] A first obtaining module is configured to obtain a secondary side network voltage of the traction transformer and an AC side voltage of a traction converter; the AC side of the traction converter is connected to a secondary side winding of the traction transformer, and the secondary side network voltage is obtained according to a primary side network voltage of the traction transformer and a transformation ratio;

[0060] A first determining module is configured to 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 taking a primary side current and a secondary side current of the traction transformer as state variables;

[0061] A first calculating module is configured to obtain 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;

[0062] A second determining module is configured to determine an actual state of the traction transformer based on the winding current estimation value and an actual winding current value, wherein the actual state is a fault state or a normal state.

[0063] To solve the above technical problems, the application further provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the steps of the fault detection method of the traction transformer according to any one of the above.

[0064] To solve the above technical problems, the application further provides an electronic device, comprising:

[0065] A memory is configured to store a computer program;

[0066] A processor is configured to implement the steps of the fault detection method of the traction transformer according to any one of the above when executing the computer program.

[0067] To solve the above technical problems, the application further provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program, when executed by a processor, implements the steps of the fault detection method of the traction transformer according to any one of the above.

[0068] The application provides a fault detection method of a traction transformer, in which, during actual operation of a train, the secondary side network voltage of the traction transformer and the alternating current side voltage of a traction converter are detected online, the secondary side voltage of the traction transformer and the alternating current side voltage of the traction converter are substituted into a state equation previously established with the primary side current and the secondary side current of the traction transformer as state variables, and the winding current estimation value 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, whether the winding current estimation value of the traction transformer in a normal state matches the actual winding current value of the traction transformer can be used to determine the actual state of the traction transformer, the actual state of the traction transformer is detected in real time during operation of the train, early warning and protection are realized, the response speed is fast, no additional sensors are needed, and the hardware cost of fault detection is low. The application also provides a fault detection system of a traction transformer, a computer program product, an electronic device and a computer readable storage medium, which have the same beneficial effects as the above-mentioned fault detection method of the traction transformer. BRIEF DESCRIPTION OF DRAWINGS

[0069] In order to more clearly illustrate the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0070] Fig. 1 is a step flow chart of a fault recognition method of a traction transformer provided by the present application;

[0071] Fig. 2 is a waveform diagram of the actual value and the estimation value of the primary side current when the traction transformer is in a normal state provided by the present application;

[0072] Fig. 3 is a waveform diagram of the actual value and the estimation value of the secondary side current when the traction transformer is in a normal state provided by the present application;

[0073] Fig. 4 is a waveform diagram of the actual value and the estimation value of the primary side current when the traction transformer is in a fault state provided by the present application;

[0074] Fig. 5 is a waveform diagram of the actual value and the estimation value of the secondary side current when the traction transformer is in a fault state provided by the present application;

[0075] Fig. 6 is an equivalent circuit diagram of a traction converter provided by the present application;

[0076] Fig. 7 is a schematic diagram of the network side part of a train traction system provided by the present application;

[0077] Fig. 8 is an equivalent circuit diagram of a traction transformer provided by the present application;

[0078] Fig. 9 is a schematic diagram of a structure of a fault identification system of a traction transformer provided by the present application;

[0079] Fig. 10 is a schematic diagram of a structure of an electronic device provided by the present application;

[0080] Fig. 11 is a schematic diagram of a structure of a computer-readable storage medium provided by the present application. DETAILED DESCRIPTION

[0081] The core of the present application is to provide a traction transformer fault identification method, system, product, device and medium, which can detect in real time during train operation, provide early warning and protection, has fast response speed, does not need to add additional sensors, and reduces the hardware cost of fault detection.

[0082] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0083] In a first aspect, the present application provides a step flowchart of a traction transformer fault identification method, which comprises:

[0084] S101: obtaining a secondary side network voltage of a traction transformer and an alternating current side voltage of a traction converter; the alternating current side of the traction converter is connected with a secondary side winding of the traction transformer, and the secondary side network voltage is obtained according to a primary side network voltage of the traction transformer and a transformation ratio;

[0085] In this embodiment, in a train traction system, a primary side winding of a traction transformer is connected with a power grid, and a secondary side winding of the traction transformer is connected with a traction converter, so as to convert a power grid voltage into a voltage required by the traction converter for use by the traction converter. The traction transformer comprises one primary side winding and at least one secondary side winding, and the number of the secondary side windings is set according to actual engineering needs.

[0086] It can be understood that the secondary side network voltage of the traction transformer specifically refers to a power grid voltage of the secondary side winding of the traction transformer, and both the secondary side network voltage and the alternating current side voltage can select a transient value. In this embodiment, the secondary side network voltage of the traction transformer and the alternating current side voltage of the traction converter can be obtained according to a control period, or the secondary side network voltage of the traction transformer and the alternating current side voltage of the traction converter can be obtained after receiving a trigger instruction. The present embodiment does not limit the trigger condition for obtaining the secondary side network voltage of the traction transformer and the alternating current side voltage of the traction converter.

[0087] S102: Determine the state equation corresponding to the traction transformer, the state equation is obtained based on the equivalent circuit of the traction transformer, and the primary current and the secondary current of the traction transformer are state variables;

[0088] The state equation in this embodiment is a state equation established in advance based on the equivalent circuit of the traction transformer, with the primary current and the secondary current of the traction transformer as state variables, which is used to solve the primary current estimate and the secondary current estimate of the traction transformer. The state equation is stored in a preset position, and the state equation can be directly read from the preset position in this embodiment. 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 this embodiment is not limited herein.

[0089] S103: Obtain the winding current estimate corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation;

[0090] In this embodiment, the AC side voltage and the secondary side network voltage are substituted into the state equation, and the winding current estimate of the traction transformer in the normal state is obtained, which includes the primary current estimate and the secondary current estimate. The state equation in this embodiment is determined according to the equivalent circuit of the traction transformer, which is adapted to the actual working condition of the traction transformer in the traction system, so that the primary current estimate and the secondary current estimate of the traction transformer obtained by estimation are more accurate.

[0091] S104: Determine the actual state of the traction transformer based on the winding current estimate and the winding current actual value, the actual state being a fault state or a normal state.

[0092] In this embodiment, considering that when the traction transformer is in the normal state, the actual value and the estimate value of the primary current and the secondary current of the traction transformer have waveforms as shown in FIGS. 2 and 3, the winding current actual value and the winding current estimate value are almost completely consistent. When the secondary winding or the primary winding of the traction transformer occurs inter-turn short circuit, the actual value and the estimate value of the primary current and the secondary current of the traction transformer have waveforms as shown in FIGS. 4 and 5, and the winding current of the traction transformer will change significantly. The difference in current size can be used to determine whether a fault occurs inside the transformer.

[0093] Based on this, the embodiment can determine the actual state of the traction transformer according to the difference between the winding current estimated value and the winding current actual value. If the winding current estimated value and the winding current actual value are approximately consistent, it is considered that the actual state of the traction transformer is a normal state. If the difference between the winding current estimated value and the winding current actual value is too large, it is considered that the actual state of the traction transformer is a fault state.

[0094] As an optional embodiment, in order to increase the fault tolerance and improve the reliability of the fault identification result, the embodiment can detect the duration of the difference between the winding current estimated value and the winding current actual value being too large. If the duration exceeds the preset time, it is determined that the actual state of the traction transformer is a normal state at this time. Otherwise, it is determined that the actual state of the traction transformer is a fault state, and an alarm information is generated at this time to prompt the driver to pay attention. When comparing the winding current actual value and the winding current estimated value, comparison can be made based on instantaneous value, amplitude, effective value, etc., which can be selected according to actual engineering needs, and the embodiment does not make specific limitation here.

[0095] Of course, in addition to the above fault tolerance mechanism, other fault tolerance schemes can also be used, and the embodiment does not make specific limitation here.

[0096] It can be seen that in the embodiment, the present application provides a fault detection method of a traction transformer. In the actual operation of the train, the secondary side network voltage of the traction transformer and the alternating current side voltage of the traction converter are detected online. The secondary side voltage of the traction transformer and the alternating current side voltage of the traction converter are substituted into the state equation previously established with the primary side current and the secondary side current of the traction transformer as state variables, and the winding current estimated value corresponding to the traction transformer is solved. 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, the present application can determine the actual state of the traction transformer according to whether the estimated winding current estimated value of the traction transformer in the normal state matches the winding current actual value of the traction transformer. The actual state of the traction transformer is determined in real time during the operation of the train, early warning and protection are realized, the response speed is fast, no additional sensors are needed, and the hardware cost of fault detection is low.

[0097] On the basis of the above embodiment:

[0098] As an optional embodiment, the process of obtaining the alternating current side voltage of the traction converter includes:

[0099] In the operation process of the traction converter, the intermediate direct current voltage of the traction converter and the driving signal for controlling each switch tube in the traction converter are obtained.

[0100] The AC side voltage of the traction converter is calculated based on the drive signal and the intermediate DC voltage.

[0101] Referring to Figure 6, the process of obtaining the AC side voltage of the traction converter is explained. Figure 6 shows the equivalent circuit diagram of a single-phase four-quadrant converter. The single-phase four-quadrant converter includes two bridge arms, each including an upper switch and a lower switch. The first bridge arm in Figure 6 includes an upper switch T1 and a lower switch T2, and the second bridge arm includes an upper switch T3 and a lower switch T4. It can be understood that when controlling the traction converter, the upper and lower switches in the two bridge arms are complementary in conduction. Assuming that the drive signals of the four switches are P1 to P4, a value of 1 indicates that the corresponding switch is on, and a value of 0 indicates that the corresponding switch is off, the following formula can be obtained: u c1 =u d (P1-P3);

[0102] Among them, u c1 The AC side voltage of the traction converter, u d P1 is the drive signal for the upper switch T1 of the first bridge arm, and P3 is the drive signal for the upper switch 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 switch, the AC side voltage of the traction converter can be obtained using the above formula. The AC side voltage can then be calculated using the TCU (Traction Control Unit), which is cost-effective. Of course, Figure 6 only shows a single-phase, two-level converter. For traction converters with three-phase, four-phase, three-level, and five-level topologies, the conversion formula is slightly different, but all involve multiplying the intermediate DC voltage by the switching function to obtain the AC side voltage; the same principle applies to others.

[0103] As another alternative embodiment, in addition to calculating the AC side voltage by acquiring the drive signal and intermediate DC voltage of the traction converter, a voltage sensor can be added directly to measure the AC side voltage.

[0104] As an optional embodiment, the fault detection method for traction transformers further includes:

[0105] Obtain the equivalent circuit of the traction transformer;

[0106] The mathematical model of the traction transformer is determined based on the equivalent circuit.

[0107] Based on the mathematical model, the state equations with the primary and secondary currents of the traction transformer as state variables are obtained.

[0108] In this embodiment, the train traction system network side part is shown in Figure 7, the primary winding of the traction transformer is L1, the secondary winding can have multiple, set as L2, L3, …, in the actual train operation process, the primary winding or the secondary winding can exist inter-turn short circuit or other types of faults. In order to realize the identification of the internal fault of the transformer, the data modeling of the traction transformer is first carried out in this embodiment.

[0109] Referring to Figure 7, a mathematical model of the traction transformer is established taking a single secondary winding as an example. First, referring to Figure 8, it is a T-type equivalent circuit diagram of the traction transformer. According to the equivalent circuit diagram, the mathematical model of the traction transformer is established as follows:

[0110] Wherein, 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, L 1σ is the first equivalent inductance, L 2σ 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, which is written in the standard form as:

[0112] Wherein,

[0113] Wherein, u g is the primary network voltage u s of the traction transformer, and the secondary network voltage converted according to the transformer ratio K, the transformation formula is:

[0114] Through the above related formulas, it can be obtained that the input signal of the mathematical model is the secondary network voltage u g and the AC side voltage u c1 of the traction converter, the former is an external condition, which changes with the change of power supply, and the latter is determined by the control signal in real-time control. It can be understood that according to the difference of current direction, the mathematical model of the traction converter can exist certain difference.

[0115] As an optional embodiment, the process of obtaining the equivalent circuit of the traction transformer includes:

[0116] Determine the equivalent type of the traction transformer;

[0117] Determine the equivalent circuit of the traction transformer according to the equivalent type.

[0118] In this embodiment, the equivalent circuit of the traction transformer can be of type T or type I, or other types, depending on the actual engineering needs. This embodiment does not limit the type of circuit.

[0119] As an optional embodiment, the process of obtaining the estimated winding current of the traction transformer based on the AC side voltage, secondary grid voltage, and state equation includes:

[0120] Determine the numerical solution algorithm for the traction transformer and the solution time step;

[0121] The state equations are solved by numerical calculation algorithm, solution time step, AC side voltage, and secondary grid voltage to obtain the estimated value of the winding current of the traction transformer.

[0122] In this embodiment, the secondary grid voltage u of the traction transformer is calculated. g and the AC side voltage u of the traction converter c1 , will u g with u g Substitute as input Get i1 and i g1 Given a state equation for the state variables, solve this state equation.

[0123] First, determine the time step for solving the problem, which is the time step in this embodiment, denoted as T. s Then, the fourth-order Runge-Kutta algorithm (or other numerical methods such as forward Euler method, backward Euler method, trapezoidal method, etc.) can be used to solve it.

[0124] When selecting a numerical solution method, one can choose based on the required solution efficiency and hardware resource status. This embodiment does not impose any specific limitations.

[0125] As an optional embodiment, the winding current estimate includes the primary current estimate and the secondary current estimate, and the actual winding current value includes the actual primary current value and the actual secondary current value.

[0126] The process of determining the actual state of a traction transformer based on estimated and actual winding current values ​​includes:

[0127] The excitation current estimate is obtained based on the primary current estimate and the secondary current estimate.

[0128] The actual value of the excitation current is obtained based on the actual values ​​of the primary current and the secondary current.

[0129] The actual condition of the traction transformer is determined based on the estimated and actual values ​​of the excitation current.

[0130] Referring to the mathematical model above, the excitation current i mThe primary current i1 and the secondary current i2 can be based on the primary current i1 and the secondary current i2 g1 The difference between the estimated value and the actual value of the field current can be used to determine the state of the traction transformer. The change in the field current can sensitively reflect the minor faults inside the transformer, such as winding short circuit and insulation aging, so that the faults can be found and handled before they become serious problems. Moreover, the field current is directly related to the magnetic flux inside the transformer, so it can accurately reflect the fault conditions inside the transformer.

[0131] As an optional embodiment, 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.

[0132] The process of determining the actual state of the traction transformer based on the winding current estimated value and the winding current actual value includes:

[0133] Obtaining the primary current actual value of the traction transformer;

[0134] Calculating the primary current difference value between the primary current actual value and the primary current estimated value;

[0135] Determining whether the primary current difference value is greater than a first preset value;

[0136] If yes, determining that the actual state of the traction transformer is a fault state;

[0137] And / or,

[0138] Obtaining the secondary current actual value of the traction transformer;

[0139] Calculating the secondary current difference value between the secondary current actual value and the secondary current estimated value;

[0140] Determining whether the secondary current difference value is greater than a second preset value;

[0141] If yes, determining that the actual state of the traction transformer is a fault state.

[0142] In this embodiment, the first preset value and the second preset value can be the same or different, and can be selected according to actual engineering needs. This embodiment does not make specific limitations here.

[0143] As an optional embodiment, the process of obtaining the secondary network voltage of the traction transformer and the AC side voltage of the traction converter includes:

[0144] Obtaining the secondary network voltage of the traction transformer and the AC side voltage of the traction converter in the current control period;

[0145] The process of obtaining the estimated winding current value of the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation comprises:

[0146] The estimated primary side current value and the estimated secondary side current value of the traction transformer are obtained according to the AC side voltage, the secondary side network voltage and the state equation of the current control period.

[0147] In the embodiment, the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter can be obtained according to the preset period, so that the actual state of the traction transformer is detected according to the preset control period in the embodiment, the reliability is high, and the abnormality of the traction transformer can be found in time.

[0148] In the present application, the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter and the actual primary side current and the actual secondary side current can be obtained when the current control period is reached, so as to be compared subsequently.

[0149] As an optional embodiment, the process of obtaining the actual primary side current value of the traction transformer comprises:

[0150] The primary side current sampling value of the traction transformer in the current control period is taken as the actual primary side current value of the traction transformer.

[0151] And / or,

[0152] The process of obtaining the actual secondary side current value of the traction transformer comprises:

[0153] The secondary side current sampling value of the traction transformer in the current control period is taken as the actual secondary side current value of the traction transformer.

[0154] In the embodiment, the primary side current sampling value and the secondary side current sampling value in the current control period are respectively taken as the actual primary side current value and the actual secondary side current value, and the estimated primary side current value and the estimated secondary side current value calculated in the current control period are compared, so as to determine whether the traction transformer has a fault in the current control period, thereby improving the reliability of the identification result.

[0155] As an optional embodiment, the process of obtaining the actual primary side current value of the traction transformer comprises:

[0156] The primary side current sampling value of the traction transformer in the next control period is taken as the actual primary side current value of the traction transformer.

[0157] And / or,

[0158] The secondary side current sampling value of the traction transformer in the next control period is taken as the actual secondary side current value of the traction transformer.

[0159] In the embodiment, the primary side current estimation value and the secondary side current estimation value calculated in the current control period are taken as the current reference value in the next control period, and the primary side current sample value and the secondary side current sample value obtained when the j+1th control period arrives are directly compared with the primary side current estimation value and the secondary side current estimation value in the jth control period, so as to identify whether the traction transformer has a fault in the j+1th control period, and the identification efficiency is high, and early warning can be facilitated in time.

[0160] As an optional embodiment, the process of obtaining the actual value of the primary side current of the traction transformer comprises:

[0161] taking the average of the primary side current sample value of the traction transformer in the next control period and the primary side current sample value of the traction transformer in the current control period as the actual value of the primary side current of the traction transformer;

[0162] and / or,

[0163] taking the average of the secondary side current sample value of the traction transformer in the next control period and the secondary side current sample value of the traction transformer in the current control period as the actual value of the secondary side current of the traction transformer.

[0164] In the embodiment, the average of the primary side current sample value in the jth control period and the primary side current sample value in the j+1th control period is obtained, and the average is compared with the primary side current estimation value calculated in the jth control period, so as to determine whether the transformer has a primary side winding inter-turn short circuit fault or the like in the j+1th control period. By comparing the average with the estimation value, the misjudgment caused by random fluctuations or noise of a single sample value can be reduced. The average can smooth the fluctuations in a short period, provide an estimation closer to the actual value, and the comparison with the estimation value can reduce the measurement error, thereby improving the identification accuracy. The same applies to the fault detection of the secondary side of the traction transformer.

[0165] In summary, the present application can not depend on a vibration signal monitoring element, a gas concentration monitoring element, a chromatographic signal monitoring element, a temperature monitoring element and the like; does not need to add an electrical quantity sensor; can judge in real time during train operation, provide early warning and protection in advance, and has a fast response speed; is realized by pure software through a TCU, does not need other hardware cooperation, and is simple and convenient for engineering application.

[0166] In a second aspect, with reference to FIG. 9, the present application further provides a fault detection system of a traction transformer, comprising:

[0167] The first obtaining module 11 is configured to obtain the secondary side network voltage of the traction transformer and the alternating current side voltage of the traction converter; the alternating current side of the traction converter is connected with the secondary side winding of the traction transformer, and the secondary side network voltage is obtained according to the primary side network voltage of the traction transformer and the transformation ratio;

[0168] The first determining module 12 is configured to determine a state equation corresponding to the traction transformer, the state equation being a state equation obtained based on an equivalent circuit of the traction transformer and taking the primary current and the secondary current of the traction transformer as state variables;

[0169] The first calculating module 13 is configured to obtain an estimated winding current value corresponding to the traction transformer according to the AC side voltage, the secondary network voltage and the state equation;

[0170] The second determining module 14 is configured to determine an actual state of the traction transformer based on the estimated winding current value and the actual winding current value, the actual state being a fault state or a normal state.

[0171] As an optional embodiment, the process of obtaining the AC side voltage of the traction converter includes:

[0172] During the operation of the traction converter, the intermediate DC voltage of the traction converter and a driving signal for controlling each switch tube in the traction converter are obtained;

[0173] The AC side voltage of the traction converter is calculated according to the driving signal and the intermediate DC voltage.

[0174] As an optional embodiment, the fault detection system of the traction transformer further includes:

[0175] The second obtaining module is configured to obtain an equivalent circuit of the traction transformer;

[0176] The third determining module is configured to determine a mathematical model of the traction transformer according to the equivalent circuit;

[0177] The second calculating module is configured to obtain a state equation taking the primary current and the secondary current of the traction transformer as state variables based on the mathematical model.

[0178] As an optional embodiment, the process of obtaining the equivalent circuit of the traction transformer includes:

[0179] An equivalent type of the traction transformer is determined;

[0180] The equivalent circuit of the traction transformer is determined according to the equivalent type.

[0181] As an optional embodiment, the process of obtaining the estimated winding current value corresponding to the traction transformer according to the AC side voltage, the secondary network voltage and the state equation includes:

[0182] A numerical solution algorithm corresponding to the traction transformer and a solution time step are determined;

[0183] The state equation is solved according to the numerical solution algorithm, the solution time step, the AC side voltage and the secondary network voltage, so as to obtain the estimated winding current value corresponding to the traction transformer.

[0184] As an optional embodiment, the winding current estimated value comprises a primary side current estimated value and a secondary side current estimated value, and the winding current actual value comprises a primary side current actual value and a secondary side current actual value;

[0185] The process of determining the actual state of the traction transformer based on the winding current estimated value and the winding current actual value comprises:

[0186] The excitation current estimated value is obtained based on the primary side current estimated value and the secondary side current estimated value;

[0187] The excitation current actual value is obtained based on the primary side current actual value and the secondary side current actual value;

[0188] The actual state of the traction transformer is determined according to the excitation current estimated value and the excitation current actual value.

[0189] As an optional embodiment, the winding current estimated value comprises a primary side current estimated value and a secondary side current estimated value, and the winding current actual value comprises a primary side current actual value and a secondary side current actual value;

[0190] The process of determining the actual state of the traction transformer based on the winding current estimated value and the winding current actual value comprises:

[0191] The primary side current actual value of the traction transformer is obtained;

[0192] The primary side current difference value of the primary side current actual value and the primary side current estimated value is calculated;

[0193] It is judged whether the primary side current difference value is greater than a first preset value;

[0194] If yes, it is determined that the actual state of the traction transformer is a fault state;

[0195] And / or,

[0196] The secondary side current actual value of the traction transformer is obtained;

[0197] The secondary side current difference value of the secondary side current actual value and the secondary side current estimated value is calculated;

[0198] It is judged whether the secondary side current difference value is greater than a second preset value;

[0199] If yes, it is determined that the actual state of the traction transformer is a fault state.

[0200] As an optional embodiment, the process of obtaining the secondary side network voltage of the traction transformer and the alternating current side voltage of the traction converter comprises:

[0201] The secondary side network voltage of the traction transformer and the alternating current side voltage of the traction converter in a current control period are obtained;

[0202] The process of obtaining the estimated winding current value of the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation comprises:

[0203] The process of obtaining the estimated primary side current value and the estimated secondary side current value of the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation of the current control cycle.

[0204] As an optional embodiment, the process of obtaining the actual primary side current value of the traction transformer comprises:

[0205] The sampled primary side current value of the traction transformer of the current control cycle is taken as the actual primary side current value of the traction transformer;

[0206] and / or,

[0207] The process of obtaining the actual secondary side current value of the traction transformer comprises:

[0208] The sampled secondary side current value of the traction transformer of the current control cycle is taken as the actual secondary side current value of the traction transformer.

[0209] As an optional embodiment, the process of obtaining the actual primary side current value of the traction transformer comprises:

[0210] The sampled primary side current value of the traction transformer of the next control cycle is taken as the actual primary side current value of the traction transformer;

[0211] and / or,

[0212] The sampled secondary side current value of the traction transformer of the next control cycle is taken as the actual secondary side current value of the traction transformer.

[0213] As an optional embodiment, the process of obtaining the actual primary side current value of the traction transformer comprises:

[0214] The average of the sampled primary side current value of the traction transformer of the next control cycle and the sampled primary side current value of the traction transformer of the current control cycle is taken as the actual primary side current value of the traction transformer;

[0215] and / or,

[0216] The average of the sampled secondary side current value of the traction transformer of the next control cycle and the sampled secondary side current value of the traction transformer of the current control cycle is taken as the actual secondary side current value of the traction transformer.

[0217] In a third aspect, the present application further provides a computer program product comprising computer programs / instructions which, when executed by a processor, implement the steps of the traction transformer fault detection method described in any one of the above embodiments.

[0218] The computer program product provided by the present application has the same beneficial effects as the traction transformer fault detection method described above.

[0219] The computer program product provided by the present application has the same beneficial effects as the traction transformer fault detection method described above.

[0220] In a fourth aspect, referring to FIG. 10, the present application further provides an electronic device, comprising:

[0221] a memory 21 for storing a computer program;

[0222] a processor 22 for executing the computer program to implement the steps of the traction transformer fault detection method described in any one of the above embodiments.

[0223] The electronic device further comprises:

[0224] an input interface 23 connected to the processor 22 via a communication bus 26, for obtaining the computer program, parameters and instructions imported from outside, and saving them into the memory 21 under the control of the processor 22. The input interface can be connected to an input device to receive the parameters or instructions manually input by a user. The input device can be a touch layer overlaid on a display screen, or a key, trackball or touchpad arranged on the terminal shell.

[0225] a display unit 24 connected to the processor 22 via the communication bus 26, for displaying the data sent by the processor 22. The display unit can be a liquid crystal display screen or an electronic ink display screen, etc.

[0226] a network port 25 connected to the processor 22 via the communication bus 26, for communicating with each terminal device outside. The communication technology used by the communication connection can be wired communication technology or wireless communication technology, such as mobile high-definition link technology, universal serial bus, high-definition multimedia interface, wireless fidelity technology, Bluetooth communication technology, low-power Bluetooth communication technology, IEEE 802.11s-based communication technology, etc.

[0227] The electronic device provided by the present application has the same beneficial effects as the traction transformer fault detection method described above.

[0228] The electronic device provided by the present application has the same beneficial effects as the traction transformer fault detection method described above.

[0229] In a fifth aspect, referring to FIG. 11, the present application further provides a computer readable storage medium 30, which stores a computer program. When the computer program is executed by a processor, the steps of the traction transformer fault detection method described in any one of the above embodiments are implemented.

[0230] The computer readable storage medium 30 can include a U disk, a mobile hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and the like, which can store program codes.

[0231] For the computer readable storage medium provided by the present application, refer to the above-mentioned embodiments, and the present application will not be described here.

[0232] The computer readable storage medium provided by the present application has the same beneficial effects as the above-mentioned fault detection method of the traction transformer.

[0233] It should also be noted that in the present specification, the relationship 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 such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0234] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to the embodiments will be 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 application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of fault detection of a traction transformer, characterized in that, The method comprises the following steps: obtaining 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 with the secondary side winding of the traction transformer, and the secondary side network voltage is obtained according to the primary side network voltage of the traction transformer and the transformation ratio; determining the state equation corresponding to the traction transformer, which is obtained based on the equivalent circuit of the traction transformer and takes the primary side current and the secondary side current of the traction transformer as state variables; obtaining the winding current estimation value corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation; determining the 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.

2. The traction transformer fault detection method according to claim 1, characterized in that, The process of obtaining the AC side voltage of the traction converter comprises: during the operation of the traction converter, obtaining the intermediate DC voltage of the traction converter and the driving signal for controlling each switch tube in the traction converter; calculating the AC side voltage of the traction converter according to the driving signal and the intermediate DC voltage.

3. The traction transformer fault detection method of claim 1, wherein, The fault detection method of the traction transformer further comprises: obtaining the equivalent circuit of the traction transformer; determining the mathematical model of the traction transformer according to the equivalent circuit; obtaining the state equation taking the primary side current and the secondary side current of the traction transformer as state variables based on the mathematical model.

4. The traction transformer fault detection method according to claim 3, characterized in that, The process of obtaining the equivalent circuit of the traction transformer comprises: determining the equivalent type of the traction transformer; determining the equivalent circuit of the traction transformer according to the equivalent type.

5. The method of fault detection of a traction transformer according to claim 1, characterized in that, The process of obtaining the winding current estimation value corresponding to the traction transformer according to the AC side voltage, the secondary side network voltage and the state equation comprises: determining the numerical solution algorithm corresponding to the traction transformer and the solution time step; solving 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 winding current estimation value corresponding to the traction transformer.

6. The traction transformer fault detection method of claim 1, wherein, The winding current estimation value comprises a primary side current estimation value and a secondary side current estimation value, and the winding current actual value comprises a primary side current actual value and a secondary side 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 the excitation current estimation value based on the primary side current estimation value and the secondary side current estimation value; obtaining the excitation current actual value based on the primary side current actual value and the secondary side current actual value; determining the actual state of the traction transformer according to the excitation current estimation value and the excitation current actual value.

7. The method of fault detection of a traction transformer according to any one of claims 1 to 6, characterized in that, The winding current estimation value comprises a primary side current estimation value and a secondary side current estimation value, and the winding current actual value comprises a primary side current actual value and a secondary side 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 the primary side current actual value of the traction transformer; calculating the primary side current difference value of the primary side current actual value and the primary side current estimation value; determining whether the primary side current difference value is greater than a first preset value; If yes, it is determined that the actual state of the traction transformer is the fault state; and / or, An actual value of a secondary side current of the traction transformer is obtained; A difference value of the secondary side current between the actual value and the estimated value is calculated; It is determined whether the difference value is greater than a second preset value; If yes, it is determined that the actual state of the traction transformer is the fault state.

8. The traction transformer fault detection method of claim 7, wherein, The process of obtaining the secondary side network voltage of the traction transformer and the AC side voltage of the traction converter includes: The secondary side network voltage of the traction transformer and the AC side voltage of the traction converter in a current control period are obtained; 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: The estimated value of the primary side current and the estimated value of the secondary side current corresponding to the traction transformer are obtained according to the AC side voltage, the secondary side network voltage and the state equation in the current control period.

9. The traction transformer fault detection method of claim 8, wherein, The process of obtaining the actual value of the primary side current of the traction transformer includes: The sampled value of the primary side current of the traction transformer in the current control period is taken as the actual value of the primary side current of the traction transformer; and / or, The process of obtaining the actual value of the secondary side current of the traction transformer includes: The sampled value of the secondary side current of the traction transformer in the current control period is taken as the actual value of the secondary side current of the traction transformer.

10. The traction transformer fault detection method of claim 8, wherein, The process of obtaining the actual value of the primary side current of the traction transformer includes: The sampled value of the primary side current of the traction transformer in the next control period is taken as the actual value of the primary side current of the traction transformer; and / or, The sampled value of the secondary side current of the traction transformer in the next control period is taken as the actual value of the secondary side current of the traction transformer.

11. The traction transformer fault detection method of claim 8, wherein, The process of obtaining the actual value of the primary side current of the traction transformer includes: 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 is taken as the actual value of the primary side current of the traction transformer; and / or, 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 is taken as the actual value of the secondary side current of the traction transformer.

12. A fault detection system for a traction transformer, characterized in that It includes: The first obtaining module is used for obtaining 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 with the secondary side winding of the traction transformer, and the secondary side network voltage is obtained according to the primary side network voltage of the traction transformer and the transformation ratio; The first determining module is used for determining the state equation corresponding to the traction transformer, which is a state equation obtained based on the equivalent circuit of the traction transformer and taking the primary side current and the secondary side current of the traction transformer as state variables; The first calculating module is used for 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; The second determining module is used for determining the actual state of the traction transformer based on the estimated value and the actual value of the winding current, and the actual state is a fault state or a normal state.

13. A computer program product comprising computer programs / instructions, characterized in that, The computer program / instruction, when executed by the processor, implements the steps of the fault detection method of the traction transformer as claimed in any one of claims 1-11.

14. An electronic device, comprising: Comprise: a memory for storing a computer program; a processor for executing the computer program to implement the steps of the fault detection method of the traction transformer as claimed in any one of claims 1-11.

15. A computer-readable storage medium, characterized in that, The computer program is stored on the computer readable storage medium, and when executed by the processor, implements the steps of the fault detection method of the traction transformer as claimed in any one of claims 1-11.

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