Short circuit detection device and short circuit detection method for turbine generator

Abstract

A short circuit detection device for a turbine generator according to the present invention comprises: an actual field current acquisition unit for acquiring a measured value of a field current flowing through a field winding wound around a rotor of the turbine generator; a measurement-time operation condition acquisition unit for acquiring a measurement-time operation parameter value, which is a state quantity of at least one operation parameter indicating an operation condition of the turbine generator when the excitation current is measured; a reference excitation current acquisition unit for acquiring a reference value of the excitation current on the basis of a model indicating the relationship between the state quantity of at least one operating parameter and the magnitude of the excitation current and the acquired value of the operating parameter at the time of measurement; and an inter-layer short circuit determination unit configured so as to determine that an inter-layer short circuit has occurred in the field winding when the amount of deviation between the reference value of the field current and the measured value of the field current exceeds a first determination threshold value.

Description

Technical Field

[0001] This disclosure relates to a short-circuit detection device and method for a turbine generator for detecting short circuits in the excitation windings configured on the rotor of a turbine generator. Background Technology

[0002] In Patent Document 1, interlayer short circuits are detected based on the impedance change of the excitation winding configured on the rotor of a brushless excitation synchronous motor.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-139860 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] The goal is to detect short circuits in the excitation winding more accurately.

[0008] The purpose of this disclosure is to provide a short-circuit detection device and method for turbine generators that can more accurately determine whether a short circuit has occurred.

[0009] Technical means for solving technical problems

[0010] At least one embodiment of the present disclosure relates to a short-circuit detection device for a turbine generator, comprising: The actual excitation current acquisition unit is used to acquire the measured value of the excitation current flowing through the excitation winding wound on the rotor of the turbine generator. The measurement operation condition acquisition unit is used to acquire at least one operating parameter representing the operating conditions of the turbine generator as a state quantity, i.e., the measurement operation parameter value, when measuring the excitation current; A reference excitation current acquisition unit is configured to acquire a reference value of the excitation current based on a model representing the relationship between a state variable of the at least one operating parameter and the magnitude of the excitation current, and the acquired operating parameter value at the time of measurement; and The interlayer short circuit determination unit is configured to determine that an interlayer short circuit has occurred in the excitation winding when the deviation between the reference value of the excitation current and the measured value of the excitation current exceeds a first determination threshold.

[0011] At least one embodiment of the present disclosure relates to a short-circuit detection method for a turbine generator, which includes: Actual excitation current acquisition steps for obtaining a measured value of the excitation current flowing through the excitation winding wound on the rotor of a turbine generator. The step of obtaining the state quantity of at least one operating parameter representing the operating conditions of the turbine generator when measuring the excitation current, i.e., the measurement operating parameter value; A reference excitation current acquisition step for obtaining a reference value of the excitation current based on a model representing the relationship between a state variable of the at least one operating parameter and the magnitude of the excitation current, and the obtained operating parameter values ​​at the time of measurement; and An interlayer short circuit determination step is configured to determine that an interlayer short circuit has occurred in the excitation winding when the deviation between the reference value of the excitation current and the measured value of the excitation current exceeds a first determination threshold.

[0012] Invention Effects

[0013] According to this disclosure, a short-circuit detection device and method for turbine generators can be provided that can more accurately determine whether a short circuit has occurred. Attached Figure Description

[0014] Figure 1 This is a schematic diagram showing the internal structure of a turbine generator according to one embodiment.

[0015] Figure 2 This is a schematic cross-sectional view of a rotor core orthogonal to the axial direction according to one embodiment.

[0016] Figure 3 This is a schematic perspective view of the axial end of a rotor according to one embodiment.

[0017] Figure 4 This is a schematic diagram illustrating a short-circuit detection device according to one embodiment.

[0018] Figure 5 It is a schematic graph showing the changes of the actual excitation current and the reference excitation current over time in one embodiment (when an interlayer short circuit occurs).

[0019] Figure 6 This is a schematic diagram showing a data table of the reduction in the number of turns according to one embodiment.

[0020] Figure 7 It is a schematic graph showing the changes of the actual excitation current and the reference excitation current over time in one embodiment (when an inter-slot short circuit occurs).

[0021] Figure 8A This is a schematic diagram of the model involved in Implementation Method 1.

[0022] Figure 8B This is a schematic diagram of the model involved in Implementation Method 2.

[0023] Figure 9 This is a flowchart of a short-circuit detection process according to one implementation method. Detailed Implementation

[0024] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the constituent components described in the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, but are merely illustrative examples.

[0025] For example, expressions indicating relative or absolute configurations such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" not only indicate that the configuration is strictly so, but also indicate that there are tolerances, or that the relative displacement is at an angle or distance to the extent that the same function can be obtained.

[0026] For example, expressions such as "same," "equal," and "homogeneous" that indicate that things are in an equal state not only indicate a state of strict equality, but also indicate a state of difference in the degree to which the same function can be obtained, where there is a tolerance.

[0027] For example, the terms "quadrilateral" and "cylindrical" not only refer to the geometrically strict meaning of quadrilaterals and cylinders, but also to shapes that include concave and convex parts, chamfered parts, etc., within the range where the same effect can be achieved.

[0028] On the other hand, expressions that "include," "contain," or "have" a certain constituent element are not exclusive expressions that exclude the existence of other constituent elements.

[0029] Furthermore, for the same composition, sometimes the same labels are used and the explanation is omitted.

[0030] <Overview of Turbine Generator 1>

[0031] Figure 1 This is a schematic diagram of a turbine generator 1 according to one embodiment of the present disclosure. The turbine generator 1 includes a rotor 6 integral with a rotor shaft 7, a stator 2 located on the outer periphery of the rotor 6, and a housing 4 housing the rotor 6 and the stator 2. The housing 4 supports the rotor shaft 7 via bearings B1 and B2. In the following description, the direction in which the axis 7C of the rotor shaft 7 extends is sometimes simply referred to as the "axial direction". In addition, the circumferential and radial directions based on the axis 7C are sometimes simply referred to as the "circumferential direction" and the "radial direction", respectively. The radial inner side is the direction side closer to the axis 7C, and the radial outer side is the direction side farther away from the axis 7C.

[0032] Rotor 6 includes a rotor core 10 integral with rotor shaft 7, and a plurality of slots 11 formed on rotor core 10 (see reference). Figure 2 The rotor 2 includes a stator core 5 and a stator coil 3 wound on the stator core 5. The stator coil 3 has a coil end 3a protruding axially from the stator core 5 and a lead-out portion 3b connected to an external electrical system (not shown).

[0033] The rotor shaft 7 is connected to a turbine (not shown) such as a gas turbine or steam turbine. The turbine generator 1 is a synchronous generator, and its working principle is as follows: When the turbine, which acts as the prime mover, rotates the rotor 6, which is formed by mounting excitation windings 12 on the rotor core 10 integrated with the rotor shaft 7, the excitation current flowing through the excitation windings 12 generates a circumferential magnetic flux. This magnetic flux links with the stator coils 3 as the rotor 6 rotates, thereby generating electricity. The generated electricity is supplied to the external electrical system (more specifically, the load) via the lead-out section 3b.

[0034] <Structure of Rotor 6>

[0035] Reference Figure 2 , Figure 3 A more detailed description of the structure of rotor 6 will be provided. Figure 2 This is a schematic cross-sectional view of a rotor core 10 orthogonal to the axial direction according to an embodiment of this disclosure. Figure 3 This is a schematic perspective view of the axial end of the rotor 6 according to one embodiment of the present disclosure.

[0036] The rotor core 10 has a plurality of slots 11 arranged circumferentially. Each slot 11 is a groove extending axially. The excitation winding 12 includes an axially extending portion 12a extending axially in each slot 11 and a circumferentially extending portion 12b extending circumferentially. The circumferentially extending portion 12b is connected to the portion of the axially extending portion 12a that protrudes axially from the slot 11, forming the axial end of the excitation winding 12.

[0037] Multiple axial extensions 12a, each disposed in a plurality of slots 11, are arranged circumferentially (see reference). Figure 2 Furthermore, multiple circumferential extensions 12b, each connected to a plurality of axial extensions 12a, are arranged axially (see reference). Figure 3 A spacer 14 made of insulating material is disposed between two adjacent circumferential extensions 12b in the axial direction.

[0038] A wedge 13 extending axially is embedded in each groove 11. The wedge 13 covers the axial extension 12a from the radially outer side, thereby preventing the axial extension 12a from dislodging from the groove 11 under centrifugal force. In addition, the circumferential extension 12b is covered by a retaining ring 16 provided on the axial end of the rotor shaft 7.

[0039] Although detailed illustrations are omitted, the excitation winding 12 has a structure in which conductors made of metal such as copper are wound around the rotor core 10. Furthermore, each axial extension 12a and each circumferential extension 12b has a structure in which layers of wound conductors are stacked radially in multiple layers. An insulating member (not shown) is disposed between two radially adjacent layers. Generally, in the case of a two-pole motor, the sum of the number of conductor layers in each slot from pole to pole is consistent with the total number of turns of the excitation winding 12.

[0040] return Figure 1 Continuing with the overview of turbine generator 1, a short circuit can occur in the excitation winding 12 during operation of turbine generator 1. An example of this short circuit is an inter-layer short circuit. An inter-layer short circuit refers to a short circuit occurring in a specific slot 11 (see reference 1). Figure 2 In this embodiment, a short circuit occurs due to at least two of the multiple layered portions constituting the axial extension 12a coming into contact with each other. The turbine generator 1 of this embodiment includes a turbine generator short circuit detection device 90 having the function of detecting interlayer short circuits. The turbine generator short circuit detection device 90 is implemented by a controller or control panel. Alternatively, the turbine generator short circuit detection device 90 may also be constituted by a DCS panel constituting one of multiple control panels. In the following description, "turbine generator short circuit detection device 90" will sometimes be abbreviated as "short circuit detection device 90".

[0041] <Basic Structure of Short Circuit Detection Device 90>

[0042] Figure 4 This is a schematic diagram illustrating a short-circuit detection device 90 according to one embodiment of the present disclosure. Before describing the basic structure of the short-circuit detection device 90, the principle of how the short-circuit detection device 90 detects interlayer short circuits will be explained. In this embodiment, whether an interlayer short circuit has occurred is determined by comparing the measured value of the excitation current flowing through the excitation winding 12 (hereinafter sometimes referred to as the actual excitation current) with a reference value of the excitation current (hereinafter sometimes referred to as the reference excitation current). The reference excitation current is the normal value of the excitation current that is expected to be obtained as a measured value when measuring the actual excitation current. More specifically, the reference excitation current is the excitation current that is presumed to actually flow through the excitation winding 12 under the operating conditions of the turbine generator 1 when measuring the actual excitation current, assuming that no interlayer short circuit has occurred.

[0043] Figure 5 This is a schematic graph showing the changes in actual excitation current and reference excitation current over time. If an interlayer short circuit occurs when measuring the actual excitation current, the current path in excitation winding 12 will be shortened, and the overall resistance of excitation winding 12 will decrease. As a result, the actual excitation current will be much larger than the reference excitation current. Figure 5 In the example, when the deviation (ΔI) between the actual excitation current and the reference excitation current exceeds the first judgment threshold (α1), which is a predetermined threshold, the short-circuit detection device 90 determines that an interlayer short circuit has occurred. Furthermore, Figure 5 The ΔI is just one example of the deviation between the actual excitation current and the reference excitation current.

[0044] The basic structure of the short-circuit detection device 90 used to detect interlayer short circuits as described above will be explained. For example... Figure 4 As shown, the short circuit detection device 90 includes an actual excitation current acquisition unit 91, a measurement operation condition acquisition unit 92, a reference excitation current acquisition unit 93, and an inter-layer short circuit determination unit 94.

[0045] The actual excitation current acquisition unit 91 is configured to acquire the actual excitation current by measuring it using the current sensor 101. The current sensor 101 is configured to measure the excitation current flowing in the axial extension 12a disposed in the slot 11.

[0046] The measurement operation condition acquisition unit 92 is configured to acquire the measurement operation parameter value Ps. The measurement operation parameter value Ps is a state quantity representing at least one operation parameter P of the turbine generator 1, and more specifically, a state quantity of the operation parameter P when measuring the actual excitation current. Furthermore, the operation parameter P is a physical quantity representing the operation conditions of the turbine generator 1. Examples of operation parameters P include the active power of the turbine generator 1, the reactive power of the turbine generator 1, the power factor of the turbine generator 1, the output voltage of the lead-in unit 3b, and the rotational speed of the rotor shaft 7. Moreover, the state quantity of the operation parameter P is a specific value of the operation parameter P, a value that can vary according to the operating conditions of the turbine generator 1. In this embodiment, the measurement operation parameter value Ps, which is the state quantity of the operation parameter P, is acquired by measurement using at least one sensor 102.

[0047] For example, when measuring active and reactive power, sensor 102 includes a voltmeter for measuring the output voltage of lead 3b and an ammeter for measuring the current flowing through lead 3b. When measuring the rotational speed of rotor shaft 7, sensor 102 includes a tachometer for measuring the rotational speed of rotor shaft 7.

[0048] The reference excitation current acquisition unit 93 is configured to acquire a reference excitation current. The reference excitation current is acquired based on the measurement-time operating parameter value Ps and a model M. In this embodiment, model M represents the relationship between at least one operating parameter P and the magnitude of the excitation current when the excitation winding 12 is not short-circuited. By applying the measurement-time operating parameter value Ps to such a model M, the reference excitation current, as an estimated value, is acquired. Model M can be a data table Tb (refer to...). Figure 8A ), machine learning model Mm (refer to) Figure 8B ) or multiple regression analysis model Mr (refer to Figure 8B The details of model M will be discussed later.

[0049] The interlayer short circuit determination unit 94 is configured to determine that an interlayer short circuit has occurred in the excitation winding 12 if the deviation between the reference excitation current and the actual excitation current exceeds a first determination threshold. The deviation can be the difference between the reference excitation current and the actual excitation current, or it can be the ratio of the reference excitation current to the actual excitation current.

[0050] When an inter-layer short circuit occurs, the actual excitation current becomes larger than in the case where no short circuit occurs because the number of turns in the excitation winding 12 decreases. Therefore, by comparing the deviation of the excitation current with a first determination threshold predetermined through experiments or simulations, it is possible to determine whether an inter-layer short circuit has occurred. Furthermore, the first determination threshold can be a fixed value or a value that varies according to the operating conditions of the turbine generator 1. In the latter case, the first determination threshold can be set based on the measurement-time operating parameter value Ps acquired by the measurement-time operating condition acquisition unit 92.

[0051] Based on the above structure, by applying the measurement operation parameter value Ps when measuring the excitation current to model M, the excitation current obtained as the measurement value when the excitation winding 12 is not short-circuited can be used as a reference value. The measured value of the excitation current when an inter-layer short circuit occurs is larger than the measured value of the excitation current when no inter-layer short circuit occurs. Therefore, the inter-layer short circuit determination unit 94 can determine whether an inter-layer short circuit has occurred by comparing the deviation between the reference excitation current and the actual excitation current with a first determination threshold. The inter-layer short circuit determination unit 94 determines whether an inter-layer short circuit has occurred based on the measured value of the excitation current that is directly affected when an inter-layer short circuit occurs. Thus, it is possible to determine whether a short circuit has occurred more accurately.

[0052] <Additional Structure to Short Circuit Detection Device 90>

[0053] Reference Figure 1 , Figure 4 , Figure 6 The structure that the interlayer short circuit determination unit 94 may also have will be explained. Figure 6This is a schematic diagram showing a data table Td representing the reduction in the number of turns according to one embodiment of this disclosure.

[0054] The inter-layer short circuit determination unit 94 can also be configured to determine the actual reduction in the number of turns of the excitation winding 12 due to the inter-layer short circuit when an inter-layer short circuit is determined to have occurred. Here, the actual reduction in the number of turns represents how much the portion of the excitation winding 12 through which the excitation current flows has decreased due to the inter-layer short circuit. For example, assuming a short circuit occurs at a point in the excitation winding 12 with a 40-turn coil structure, the total number of turns in the portion of the excitation winding 12 through which the excitation current flows decreases from 40 turns to 39 turns. In this case, the actual reduction in the number of turns is 1 turn.

[0055] The actual reduction in the number of turns is determined based on the excitation current ratio R between the reference excitation current and the actual excitation current. In this example, the excitation current ratio R is obtained by dividing the actual excitation current obtained by the actual excitation current acquisition unit 91 by the reference excitation current obtained by the reference excitation current acquisition unit 93.

[0056] As the actual number of turns decreases, the number of turns in the excitation winding 12 decreases, thus increasing the actual excitation current. For example, suppose the total number of turns in the section of the excitation winding 12 through which the excitation current flows decreases from 40 turns to 39 turns (as mentioned above, in this case, the actual number of turns decreases by 1 turn). The overall resistance of the excitation winding 12 after the inter-layer short circuit occurs is approximately 39 / 40 times the resistance before the inter-layer short circuit occurs. As a result, the actual excitation current is approximately 40 / 39 times the actual excitation current before the inter-layer short circuit occurs.

[0057] To give another example, suppose a short circuit occurs at two points in the excitation winding 12. The total number of turns in the section of the excitation winding 12 through which the excitation current flows decreases from 40 turns to 38 turns (in this case, the actual reduction in turns is 2 turns). The overall resistance of the excitation winding 12 after the inter-layer short circuit is approximately 38 / 40 times the resistance before the inter-layer short circuit. As a result, the actual excitation current is approximately 40 / 38 times the actual excitation current before the inter-layer short circuit.

[0058] As mentioned above, the greater the actual reduction in the number of turns, the greater the actual excitation current. That is, the greater the actual excitation current, the greater the excitation current ratio R. In this example, the extent to which the excitation current ratio R increases by one turn for every increase in the actual reduction in the number of turns is determined in advance through experiments or simulations. Furthermore, a data table Td for the reduction in the number of turns is created in advance based on the determined results (see...). Figure 6 In this example, the data table Td showing the reduction in the number of turns is stored in the memory of the short-circuit detection device 90. Additionally, in... Figure 6 In this context, K represents the total number of turns in the excitation winding 12.

[0059] The turns reduction data table Td correlates the excitation current ratio R with the actual turns reduction. The inter-layer short-circuit determination unit 94 obtains the excitation current ratio R based on the actual excitation current obtained by the actual excitation current acquisition unit 91 and the reference excitation current obtained by the reference excitation current acquisition unit 93. Furthermore, the inter-layer short-circuit determination unit 94 determines the actual turns reduction corresponding to the obtained excitation current ratio R in the turns reduction data table Td.

[0060] In addition, the aforementioned first determination threshold ( Figure 5 α1) is set to detect inter-layer short circuits even if the actual number of turns is reduced by only 1 turn. In other words, for convenience, it will be specified that... Figure 6 When the actual excitation current and the reference excitation current of R1 are defined as the first actual excitation current and the first reference excitation current, respectively, α1 is less than or equal to the value of the first reference excitation current × {total number of turns / (total number of turns - 1) - 1}. Furthermore, since the first reference excitation current varies depending on the generator's operating state, α1 is not a fixed value, but a variable one.

[0061] Based on the above structure, the interlayer short circuit determination unit 94 can determine the actual number of turns reduction based on the excitation current ratio R. Since the temperature of the excitation winding is calculated based on the excitation winding resistance value, the operator can understand that the excitation winding temperature has not been correctly detected. Therefore, the operator can take more appropriate measures on the turbine generator 1, such as making the output fluctuation smoother than usual and preventing damage to the excitation winding caused by interlayer short circuits. In addition, the excitation current ratio R can also be a value obtained by dividing the reference excitation current obtained by the reference excitation current acquisition unit 93 by the actual excitation current acquisition unit 91 obtained by the actual excitation current acquisition unit 91. In this case, the larger the actual number of turns reduction, the smaller the excitation current ratio R. As long as a number of turns reduction data table Td is created to determine the amount of reduction in the excitation current ratio R, the above-mentioned technical advantages can be obtained.

[0062] Reference Figure 2 , Figure 3 , Figure 4 , Figure 7 Figure 8 further illustrates the structures that can be added to the short-circuit detection device 90. The short-circuit detection device 90 can be configured to detect inter-slot short circuits. The following explains inter-slot short circuits. For convenience, when two circumferentially adjacent slots 11 are referred to as slots 11A and 11B, and the excitation windings 12 respectively disposed in slots 11A and 11B are referred to as excitation windings 12A and 12B, an inter-slot short circuit refers to a short circuit occurring between excitation windings 12A and 12B. Inter-slot short circuits may occur within the retaining ring 16. More specifically, an inter-slot short circuit may occur between the circumferential extension 12b constituting excitation winding 12A and the circumferential extension 12b constituting excitation winding 12B.

[0063] In the event of an inter-slot short circuit, a larger actual magnetizing current will be measured compared to the case where the actual number of turns is reduced by K turns (refer to...). Figure 7 This is because the number of turns in excitation winding 12 is substantially reduced by an amount corresponding to the number of conductor layers in the slots of at least one of excitation windings 12A and 12B. In other words, when determining whether an inter-slot short circuit has occurred, the threshold for comparison with the deviation between the reference excitation current and the actual excitation current is higher than the first determination threshold (…). Figure 5 The value of α1 should be larger. In this example, when the deviation ( Figure 7 In the example, ΔI) reaches a second judgment threshold that is larger than the first judgment threshold. Figure 7 When α2) or higher, an inter-slot short circuit is determined to have occurred. Furthermore, the deviation is not limited to the difference between the reference excitation current and the actual excitation current; it can also be the ratio of the reference excitation current to the actual excitation current. Additionally, the deviation between the reference excitation current and the actual excitation current is a value that varies depending on the operating state of the turbine generator 1.

[0064] This is a structure used to detect the aforementioned inter-slot short circuits. Figure 4 The short-circuit detection device 90 shown in the example also includes an inter-slot short-circuit determination unit 95. The inter-slot short-circuit determination unit 95 is configured such that if the deviation between the reference excitation current obtained by the reference excitation current acquisition unit 93 and the actual excitation current obtained by the actual excitation current acquisition unit 91 exceeds a second determination threshold, an inter-slot short circuit is determined to have occurred.

[0065] Based on the above structure, when the deviation of the excitation current is greater than or equal to a second determination threshold (which is greater than the first determination threshold), an inter-slot short circuit can be determined to have occurred. Thus, a short-circuit detection device 90 capable of identifying the type of short circuit that has occurred is realized. Furthermore, the inter-layer short-circuit determination unit 94 can be configured to determine that an inter-layer short circuit has occurred when the deviation is greater than or equal to the first determination threshold but less than the second determination threshold. Therefore, the short-circuit detection device 90 can avoid misdetecting inter-layer short circuits occurring in the excitation winding 12 as inter-slot short circuits.

[0066] <Specific Structure of Model M (Implementation Method 1)>

[0067] Figure 8AThis is a schematic diagram illustrating the model Ma (M) involved in Implementation Method 1. Model Ma is a data table Tb, which has multiple datasets Dt. Each dataset Dt corresponds a state variable of at least one operating parameter P to the magnitude of the excitation current. Each dataset Dt represents past normal operating data of the turbine generator 1. More specifically, in each dataset Dt, the magnitude of the excitation current is the excitation current measured by the current sensor 101 under the operating conditions of the turbine generator 1 as specified by the state variable of the operating parameter P. At the time of this measurement, the excitation winding 12 is not short-circuited. Each dataset Dt is created by the operator based on the measurement results of the sensor 102 and the current sensor 101, after confirming that the excitation winding 12 is not short-circuited.

[0068] The process of obtaining the reference excitation current as an estimated value by applying the measured operating parameter value Ps to the data table Tb is as follows: The reference excitation current acquisition unit 93 determines from the data table Tb a dataset Dt containing state quantities of the operating parameter P that can be considered the same as the measured operating parameter value Ps obtained by the measured operating condition acquisition unit 92. More specifically, the deviation of the state quantities between the measured operating parameter value Ps obtained by the measured operating condition acquisition unit 92 and the state quantities of the operating parameter P contained in each dataset Dt is determined for each parameter category. If the data table Tb contains a dataset Dt in which the deviations of each state quantity are all within a specified value, then the excitation current contained in that dataset Dt is acquired as the reference excitation current.

[0069] To give another detailed example, suppose that during measurement, the operating parameter value Ps and the operating parameter P each have three parameter categories (i.e., N is 3 as shown in Figure 8). In this case, the operating parameter value Ps during measurement includes the parameter value P not shown in the figure. s1 P s2 P s3 The running parameter P includes P not shown in the figure. 1M P 2M P 3M (M is any natural number). During measurement, the running condition acquisition unit 92 acquires P sequentially for each of the multiple datasets Dt. s1 -P 1M P s2 -P 2M P s3 -P 3M The deviations of these three state variables. If there exists a dataset Dt where all three deviations are within the specified values, the reference excitation current acquisition unit 93 acquires the magnitude of the excitation current contained in the dataset Dt as the reference excitation current. Furthermore, the aforementioned specified values ​​can also be values ​​set for each parameter category.

[0070] Further examples of operating parameter P are provided. When there are three parameter categories, operating parameter P can be active power, reactive power, and armature voltage (i.e., the output voltage of lead-out 3b). Alternatively, either active power or reactive power can be replaced by the power factor. Furthermore, there can be four parameter categories, and the rotational speed of rotor shaft 7 can also be added as an operating parameter P.

[0071] Based on the above structure, the reference excitation current acquisition unit 93 determines from the data table Tb a dataset Dt containing state variables of the operating parameter P that can be considered the same as the acquired operating parameter value Ps at the time of measurement, and can acquire the excitation current contained in the determined dataset Dt as the reference excitation current. In other words, from the data table Tb created based on the operating performance of the turbine generator 1, the excitation current matching the operating conditions at the time of measuring the actual excitation current is acquired as the reference excitation current. Since the reference excitation current acquired based on the operating performance has high reliability, it is possible to more accurately determine whether an interlayer short circuit has occurred.

[0072] <Specific Structure of Model M (Implementation Method 2)>

[0073] Figure 8B This is a schematic diagram illustrating the model Mb(M) involved in Implementation Method 2. Model Mb includes a machine learning model Mm or a multiple regression analysis model Mr.

[0074] The machine learning model Mm is a model that takes at least one operating parameter P as a state variable as an input parameter and the magnitude of the excitation current as an output parameter. The teacher data used to generate the machine learning model Mm is created during the rated operation of the turbine generator 1. More specifically, during the rated operation of the turbine generator 1, the measurement results of current sensors 101 and 102 are acquired at any time, and teacher data is created (the actual excitation current contained in the teacher data is the measured value of the excitation current under conditions where no short circuit occurs). In the machine learning model Mm that completes machine learning using this teacher data, when the state variable of at least one operating parameter P is input into the machine learning model Mm, the excitation current corresponding to the state variable of that operating parameter P is output from the machine learning model Mm. That is, the reference excitation current acquisition unit 93 inputs (i.e., applies) the measured operating parameter value Ps into the machine learning model Mm, thereby causing the machine learning model Mm to output a reference excitation current.

[0075] The multiple regression analysis model Mr is a model that uses at least one operating parameter P as a state variable and the magnitude of the excitation current as the target variable. Sample data for generating the multiple regression analysis model Mr can be created during the rated operation of the turbine generator 1. The process for creating the sample data is the same as the process for creating the teacher data described above. The multiple regression analysis model Mr, completed using this sample data, defines the relationship between at least one operating parameter P and the excitation current through a prescribed formula. Furthermore, when the state variable of at least one operating parameter P is input into the multiple regression analysis model Mr, the excitation current corresponding to the state variable of that operating parameter P is output. In other words, the reference excitation current acquisition unit 93 inputs the measured operating parameter value Ps into the multiple regression analysis model Mr, thereby the multiple regression model Mr outputs a reference excitation current.

[0076] According to the above structure, the reference excitation current acquisition unit 93 acquires the reference excitation current by inputting the acquired operating parameter value Ps obtained during measurement into the machine learning model Mm or the multiple regression analysis model Mr. Even when the turbine generator 1 is operating under conditions where no operating data has been accumulated, the machine learning model Mm or the multiple regression analysis model Mr can output the reference excitation current under those operating conditions. Therefore, it is possible to accurately determine whether an inter-layer short circuit has occurred under a wider range of operating conditions.

[0077] <Short Circuit Detection and Handling>

[0078] Figure 9 This is a flowchart illustrating a short-circuit detection process according to an embodiment of the present disclosure. The short-circuit detection process is an example of a short-circuit detection method for a turbine generator. The short-circuit detection process is executed by the processor (hereinafter, sometimes simply referred to as the processor) of the short-circuit detection device 90 reading a program stored in the memory of the short-circuit detection device 90. In the following description, "step" is sometimes abbreviated as "S".

[0079] First, the processor acquires the actual excitation current by measuring the current sensor 101 (S11). Furthermore, the processor acquires a measurement-time operating parameter value Ps, representing the operating conditions of the turbine generator 1 when measuring the actual excitation current, by measuring the value from at least one sensor 102 (S13). Next, the processor acquires a reference excitation current by applying the measurement-time operating parameter value Ps acquired in S13 to a model M stored in memory (S15). The processor executing S11 is an example of the actual excitation current acquisition unit 91, the processor executing S13 is an example of the measurement-time operating condition acquisition unit 92, and the processor executing S15 is an example of the reference excitation current acquisition unit 93.

[0080] Next, the processor determines whether an interlayer short circuit has occurred in the excitation winding 12 based on the deviation between the reference excitation current obtained in S15 and the actual excitation current obtained in S11 (S17). More specifically, if the deviation exceeds a first determination threshold but is lower than a second determination threshold, the processor determines that an interlayer short circuit has occurred (S17: Yes). In this case, the processor performs alarm processing (S19). More specifically, a display signal indicating that an interlayer short circuit has occurred is sent to the display constituting the short circuit detection device 90. The processor that performs the affirmative determination in S17 is an example of the interlayer short circuit determination unit 94. After performing S19, the processor ends the processing.

[0081] On the other hand, if the excitation current is below the first determination threshold, or if the excitation current is above the second determination threshold, the processor determines that no interlayer short circuit has occurred (S17: No). In this case, the processor determines whether an inter-slot short circuit has occurred (S21). More specifically, if the deviation of the excitation current is above the second determination threshold, the processor determines that an inter-slot short circuit has occurred (S21: Yes). In this case, the processor performs alarm processing (S19). More specifically, a display signal indicating that an inter-slot short circuit has occurred is sent to the display of the short circuit detection device 90. The processor that performs the affirmative determination in S21 is an example of the inter-slot short circuit determination unit 95. If the excitation winding 12 is below the first determination threshold, the processor determines that no inter-slot short circuit has occurred (S21: No) and ends the short circuit detection processing.

[0082] <Other>

[0083] The aforementioned short-circuit detection device 90 is composed of a computer, including a processor, a memory (storage medium), and an external communication interface. The processor can be a CPU, GPU, MPU, DSP, or a combination thereof. In other embodiments, the processor can also be implemented using integrated circuits such as PLDs, ASICs, FPGAs, or MCUs. The memory is configured to temporarily or non-temporarily store various data, for example, using at least one of RAM, ROM, or flash memory. The processor executes various control processes according to instructions from the program loaded into the memory.

[0084] Summary

[0085] The contents described in the above-described embodiments can be understood, for example, as follows.

[0086] 1) One embodiment of the present disclosure includes a short-circuit detection device (90) for a turbine generator, comprising: Actual excitation current acquisition unit (91) is used to acquire the measured value of the excitation current flowing through the excitation winding (12) wound on the rotor (6) of the turbine generator (1); The measurement operation condition acquisition unit (92) is used to acquire at least one operating parameter (P) representing the operating conditions of the turbine generator as a state quantity, i.e., the measurement operation parameter value (Ps), when measuring the excitation current. A reference excitation current acquisition unit (93) is used to acquire a reference value of the excitation current based on a model (M) representing the relationship between a state variable of the at least one operating parameter and the magnitude of the excitation current, and the acquired operating parameter value at the time of measurement; and Interlayer short circuit determination unit (94) is configured to determine that an interlayer short circuit has occurred in the excitation winding when the deviation between the reference value of the excitation current and the measured value of the excitation current exceeds a first determination threshold.

[0087] Based on the structure described in 1) above, by applying the operating parameter values ​​during the measurement of the excitation current to the model, a reference value is obtained for the excitation current that should be measured when no short circuit occurs in the excitation winding. The measured value of the excitation current when an inter-layer short circuit occurs is larger than the measured value when no inter-layer short circuit occurs. Therefore, the inter-layer short circuit determination unit can determine whether an inter-layer short circuit has occurred by comparing the deviation between the reference value and the measured value with a first determination threshold. The inter-layer short circuit determination unit determines whether an inter-layer short circuit has occurred based on the measured value of the excitation current that is directly affected when an inter-layer short circuit occurs. Thus, it is possible to determine whether a short circuit has occurred more accurately.

[0088] 2) In some embodiments, the short-circuit detection device for turbine generators described in 1) above, The model includes a data table (Tb) having multiple datasets (Dt) that correspond the state variables of the at least one operating parameter to the magnitude of the excitation current.

[0089] Based on the structure described in 2) above, the reference excitation current acquisition unit can determine from the data table a dataset containing operating parameters that can be considered the same as the acquired measurement operating parameter values, and acquire the excitation current contained in the determined dataset as a reference value. In other words, it acquires the excitation current as a reference value from a data table created based on the operating performance of the turbine generator, matching the operating conditions at the time of actual excitation current measurement. Since the reference value of the excitation current acquired based on operating performance has high reliability, it is possible to more accurately determine whether an inter-layer short circuit has occurred.

[0090] 3) In some embodiments, the short-circuit detection device for the turbine generator described in 1) above, The model includes: a machine learning model (Mm) that takes the state variables of at least one operating parameter as input parameters and the magnitude of the excitation current as output parameters; or a multiple regression analysis model (Mr) that takes the state variables of at least one operating parameter as explanatory variables and the magnitude of the excitation current as target variables.

[0091] Based on the structure described in 3) above, the reference excitation current acquisition unit obtains the excitation current as a reference value by inputting the acquired operating parameter values ​​during measurement into a machine learning model or a multiple regression analysis model. Even when the turbine generator is operating under conditions where no operating data has been accumulated, the machine learning model or multiple regression analysis model can output a reference value of the excitation current under those operating conditions. Therefore, it is possible to accurately determine whether an inter-layer short circuit has occurred under a wider range of operating conditions.

[0092] 4) In some embodiments, in the short-circuit detection device for turbine generators described in any one of 1) to 3) above, The interlayer short circuit determination unit is configured to, when determining that an interlayer short circuit has occurred, determine the amount by which the number of turns in the part of the excitation winding through which the excitation current flows is reduced due to the interlayer short circuit, based on the ratio of the reference value of the excitation current to the measured value of the excitation current (excitation current ratio R).

[0093] According to the inventors, the greater the reduction in the total number of turns in the section through which the excitation current flows in the excitation winding due to a short circuit, the larger the measured value of the excitation current. In this respect, based on the structure described in 4) above, the actual reduction in the number of turns can be determined based on the ratio of the reference value to the measured value, thus allowing the operator to take more appropriate action on the turbine generator.

[0094] 5) In some embodiments, in the short-circuit detection device for turbine generators described in any one of 1) to 4) above, The inter-layer short circuit determination unit is configured to determine that an inter-layer short circuit has occurred when the deviation is less than a second determination threshold that is greater than the first determination threshold. The inter-layer short circuit detection device for the turbine generator also includes an inter-slot short circuit determination unit (95). The slot short circuit determination unit (95) is configured to determine that a short circuit has occurred between the excitation winding (12A) arranged in the first slot (11A) included in the rotor and the excitation winding (12B) arranged in the second slot (11B) adjacent to the first slot in the circumferential direction of the rotor when the deviation amount is greater than or equal to the second determination threshold.

[0095] According to the inventors, when an inter-slot short circuit occurs, a larger excitation current is measured than in the case where all winding portions of the excitation winding in a single slot are short-circuited. In this respect, based on the structure described in 5) above, if the deviation of the excitation current exceeds a second determination value greater than the first determination threshold, it can be determined that a short circuit has occurred between the winding coils respectively located in the two slots. Thus, a short-circuit detection device for a turbine generator capable of identifying the type of short circuit that has occurred is realized.

[0096] 6) One embodiment of the present disclosure includes a short-circuit detection method for a turbine generator, comprising: Actual excitation current acquisition step (S11) for obtaining the measured value of the excitation current flowing in the excitation winding (12) wound on the rotor (6) of the turbine generator (1). The step of obtaining the operating conditions at measurement time (S13) is used to obtain the state quantity of at least one operating parameter (P) representing the operating conditions of the turbine generator when the excitation current is measured, i.e., the operating parameter value (Ps) at measurement time. A reference excitation current acquisition step (S15) for acquiring a reference value of the excitation current based on a model (M) representing the relationship between a state variable of the at least one operating parameter and the magnitude of the excitation current, and the acquired operating parameter value at the time of measurement; and The interlayer short circuit determination step (S17) is configured to determine that an interlayer short circuit has occurred in the excitation winding if the deviation between the reference value of the excitation current and the measured value of the excitation current exceeds a first determination threshold.

[0097] Based on the structure described in 6), the same technical advantages as described in 1) can be obtained.

[0098] Label Explanation

[0099] 1: Turbine generator

[0100] 2: Stator

[0101] 3: Stator coils

[0102] 3a: Coil end

[0103] 3b: Introduction

[0104] 4: Shell

[0105] 5: Stator core

[0106] 6: Rotor

[0107] 7: Rotor shaft

[0108] 7C: Axis

[0109] 10: Rotor core

[0110] 11, 11A, 11B: Slots

[0111] 12, 12A, 12B: Excitation windings

[0112] 12a: Axial extension

[0113] 12b: Circumferential extension

[0114] 13: Wedge

[0115] 14: Spacer

[0116] 16: Keeping ring

[0117] 90: Short circuit detection device

[0118] 91: Actual Excitation Current Acquisition Section

[0119] 92: Measurement Operation Condition Acquisition Unit

[0120] 93: Reference Excitation Current Acquisition Unit

[0121] 94: Inter-layer short circuit detection unit

[0122] 95: Inter-slot short circuit determination unit

[0123] 101: Current Sensor

[0124] 102: Sensor

[0125] B1, B2: Bearings

[0126] Dt: Dataset

[0127] M, Ma, Mb: model

[0128] Mm: Machine Learning Model

[0129] Mr: Multiple Regression Analysis Model

[0130] P: Running parameters

[0131] Ps: Operating parameter values ​​during measurement

[0132] R: Excitation current ratio

[0133] Tb: Data Table

[0134] Td: Data table on the reduction in the number of turns.

Claims

1. A short-circuit detection device for a turbine generator, characterized in that, include: The actual excitation current acquisition unit is used to acquire the measured value of the excitation current flowing through the excitation winding wound on the rotor of the turbine generator. The measurement operation condition acquisition unit is used to acquire at least one operating parameter representing the operating conditions of the turbine generator as a state quantity, i.e., the measurement operation parameter value, when measuring the excitation current; A reference excitation current acquisition unit is used to acquire a reference value of the excitation current based on a model representing the relationship between a state variable of the at least one operating parameter and the magnitude of the excitation current, and the acquired operating parameter value at the time of measurement. as well as The interlayer short circuit determination unit is configured to determine that an interlayer short circuit has occurred in the excitation winding when the deviation between the reference value of the excitation current and the measured value of the excitation current exceeds a first determination threshold.

2. The short-circuit detection device for a turbine generator as described in claim 1, characterized in that, The model includes a data table having multiple datasets that correspond the state variables of the at least one operating parameter to the magnitude of the excitation current.

3. The short-circuit detection device for a turbine generator as described in claim 1, characterized in that, The model includes: a machine learning model that uses the state variables of at least one operating parameter as input parameters and the magnitude of the excitation current as output parameters; or a multiple regression analysis model that uses the state variables of at least one operating parameter as explanatory variables and the magnitude of the excitation current as target variables.

4. The short-circuit detection device for a turbine generator as described in any one of claims 1 to 3, characterized in that, The interlayer short circuit determination unit is configured to, when determining that an interlayer short circuit has occurred, determine the amount by which the number of turns in the part of the excitation winding through which the excitation current flows is reduced due to the interlayer short circuit, based on the ratio of the reference value of the excitation current to the measured value of the excitation current.

5. The short-circuit detection device for a turbine generator as described in any one of claims 1 to 3, characterized in that, The inter-layer short circuit determination unit is configured to determine that an inter-layer short circuit has occurred when the deviation is less than a second determination threshold that is greater than the first determination threshold. The inter-layer short circuit detection device for the turbine generator also includes an inter-slot short circuit determination unit, which is configured to determine that a short circuit has occurred between the excitation winding arranged in the first slot included in the rotor and the excitation winding arranged in the second slot adjacent to the first slot in the circumferential direction of the rotor when the deviation amount is above the second determination threshold.

6. A short-circuit detection method for a turbine generator, characterized in that, include: Actual excitation current acquisition steps for obtaining a measured value of the excitation current flowing through the excitation winding wound on the rotor of a turbine generator. The step of obtaining the state quantity of at least one operating parameter representing the operating conditions of the turbine generator when measuring the excitation current, i.e., the measurement operating parameter value; A reference excitation current acquisition step is used to obtain a reference value of the excitation current based on a model representing the relationship between a state variable of the at least one operating parameter and the magnitude of the excitation current, and the obtained operating parameter value at the time of measurement. as well as An interlayer short circuit determination step is configured to determine that an interlayer short circuit has occurred in the excitation winding when the deviation between the reference value of the excitation current and the measured value of the excitation current exceeds a first determination threshold.

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