Method and system for detecting faults in a generator core
A localized magnetic circuit and thermographic analysis method for generator cores addresses inefficiencies in existing fault detection, achieving efficient, low-power, and accurate fault location identification.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- CHINA GENERAL NUCLEAR POWER OPERATION
- Filing Date
- 2022-09-28
- Publication Date
- 2026-05-27
AI Technical Summary
Existing methods for diagnosing insulation faults in generator cores, such as the iron loss method and ELCID, face challenges in power consumption, equipment transportation, safety risks, and inaccurate fault location identification, leading to inefficiencies and high costs.
A method and system involving a localized magnetic circuit installation at the suspected fault location, energized to saturation, with thermographic information analysis to determine fault presence, using a low-power setup that reduces power requirements and enhances accuracy.
The method allows for efficient, low-power fault detection in generator cores, reducing power consumption, equipment transportation needs, and improving fault location accuracy, thereby minimizing time, workload, and costs.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electrical maintenance, and particularly to a method and a system for detecting faults in a generator core.
Background Art
[0002] The stator core is an important component of a large generator. Generally, it is manufactured by laminating hundreds of thousands of sector-shaped silicon steel sheets with a thickness of 0.35 mm or 0.5 mm. If poor insulation occurs between the laminated plates of the core, due to the action of the magnetic field in the operating state, a large eddy current loss will occur between the laminated plates, causing local overheating, resulting in damage to the core or the stator bar, and causing significant losses. Therefore, the insulation diagnosis of the laminated plates of the core has become an important task in the inspection and repair of generators.
[0003] Currently, the main diagnostic methods used in inspection and repair are the iron loss method and the ELCID (Electromagnetic Core Imperfection Detector) method.
[0004] The iron loss method can directly reflect the temperature rise at the fault location and evaluate the severity. However, in the iron loss test of a large generator, an MVA-class power source is often required, which is difficult to achieve in a power plant. In addition, the transportation of a large number of test devices weighing several tons and the connection of dozens of excitation cables are required. There is also a risk that the fault location will be further overheated and burned, causing secondary damage. Moreover, the diameter of the excitation cable is large, and it is necessary for personnel to enter the stator hole to measure the temperature. Furthermore, since the iron loss test must be carried out with the rotor removed, the cost is high and the risk is high. <In contrast, the ELCID method requires only a few kVA of power, making it easy to implement within a power plant. Furthermore, it boasts high sensitivity and does not cause secondary damage to the fault location. The probes used in the ELCID method are extremely small and sophisticated, allowing robots to enter the generator and perform tests without removing the rotor. However, the results obtained with the ELCID method represent the q-axis current and cannot directly reflect temperature rise. Additionally, while the ELCID method can accurately detect the presence of a fault in the core, the fault location identified by the ELCID method is often inaccurate. Therefore, if the q-axis current exceeds the standard, a supplementary iron loss test is generally required to determine whether the core fault location can operate safely; otherwise, a final determination of fault presence cannot be made. Moreover, in practice, even if the q-axis current exceeds the standard, the iron loss test may still pass, resulting in a significant waste of time, effort, and expense. [Overview of the Initiative] [Problems that the invention aims to solve]
[0006] The technical problem that this invention aims to solve is to provide a method and system for detecting a generator core failure in order to address at least one drawback of the prior art. [Means for solving the problem]
[0007] The technical means employed by this invention to solve the technical problems are as follows:
[0008] A method for detecting a generator core failure is provided to determine whether or not a failure exists in a suspected fault location within the generator core. This method includes the following steps.
[0009] S1: A localized magnetic circuit is installed at the suspected fault location to construct a magnetic circuit for measurement.
[0010] S2: The measuring magnetic circuit is energized to bring it to a predetermined saturation state and maintain that state for a predetermined time.
[0011] S3: Collect thermographic information of the measurement magnetic circuit and generate a fault determination result based on the thermographic information.
[0012] Preferably, installing a local magnetic circuit at the suspected fault location of S1 includes connecting the gear teeth on both sides adjacent to the suspected fault location with pre-installed magnetic circuit components.
[0013] Preferably, the pre-installed magnetic circuit component includes a magnetic circuit component body and an excitation winding provided on the magnetic circuit component body to supply magnetic field energy to the measuring magnetic circuit. The two contact surfaces of the magnetic circuit component body are in close contact with the surfaces of the gear teeth on both sides of the suspected fault location.
[0014] Preferably, the magnetic circuit component body includes a transverse beam and first and second side columns extending outward from both ends of the transverse beam. The effective cross-sectional area of the transverse beam, the first side columns and the second side columns is greater than or equal to the tooth tip area of the gear teeth.
[0015] Preferably, S2 includes collecting the induced voltage at the suspected fault location and adjusting the input voltage of an excitation winding having a predetermined frequency to adjust the induced voltage at the suspected fault location to be equal to a predetermined saturation voltage of the measuring magnetic circuit, and sustaining it for a predetermined time.
[0016] Preferably, the pre-installed magnetic circuit component further includes a measuring coil for measuring the induced voltage.
[0017] Accordingly, collecting the induced voltage at the suspected fault location in S2 includes collecting the measured voltage of the measuring coil and calculating the induced voltage at the suspected fault location based on the number of turns of the measuring coil and the measured voltage.
[0018] The formula for the induced voltage is Us = Ut / N2.
[0019] In the formula, Us is the induced voltage, Ut is the measured voltage, and N2 is the number of turns of the measuring coil.
[0020] Preferably, in S2, the formula for the predetermined saturation voltage is Ub = Bb * (4.44 * fb * St).
[0021] Ub is a predetermined saturation voltage, Bb is a predetermined saturation magnetic induction intensity in the measuring magnetic circuit, fb is a predetermined frequency, and St is the contact area between the magnetic circuit component body and the gear teeth.
[0022] Preferably, generating a fault determination result based on the thermographic information in S3 includes extracting temperature characteristics from the thermographic information to determine whether or not there is a region in the generator core portion of the measuring magnetic circuit where the temperature is higher than the fault temperature, determining that a fault exists in the generator core if such a region exists, and determining that there is no fault in the generator core if such a region exists.
[0023] The present invention further provides a generator core fault detection system for determining whether or not a fault exists at a suspected fault location in the generator core. The system includes pre-installed magnetic circuit components for constructing a measuring magnetic circuit, an excitation unit for exciting the constructed measuring magnetic circuit to bring it to a predetermined saturation state and maintaining it for a predetermined time, a thermographic acquisition unit for collecting thermographic information of the measuring magnetic circuit, and a determination unit for generating a fault determination result based on the thermographic information.
[0024] Preferably, the pre-installed magnetic circuit components include an excitation winding and a measuring coil, and the excitation unit includes a high-frequency power supply for applying an input voltage to the excitation winding, a voltage collector for measuring the measuring voltage of the measuring coil, and an excitation control unit for controlling the output voltage of the high-frequency power supply based on the measured voltage to bring the measuring magnetic circuit to a predetermined saturation state and maintain it for a predetermined time. [Effects of the Invention]
[0025] The present invention has at least the following beneficial effects. That is, a method for detecting a fault in a generator core is provided. In this method, first, a local magnetic circuit is installed at a suspected fault location to construct a measurement magnetic circuit, and then the measurement magnetic circuit is excited. A low-power power supply can be used for the excitation process. Even in this case, the measurement magnetic circuit can be brought into a predetermined saturation state. After maintaining it for a predetermined time, the thermography information of the measurement magnetic circuit is collected, and finally, a fault determination result is generated based on the thermography information. Compared with the conventional iron loss method, by implementing the present invention, the power required for the measurement power supply can be significantly reduced, so it can be easily realized in a nuclear power plant, and there is no need to transport a large amount of heavy test equipment. In addition, the method is simple and efficient, and can accurately determine whether there is a fault location in the core. Therefore, the time, workload, and cost of the iron loss test can be effectively reduced.
[0026] The present invention will be further described below in combination with the drawings and embodiments.
Brief Description of the Drawings
[0027] [Figure 1] FIG. 1 is a flowchart of the method for detecting a fault in a generator core provided by the present invention. [Figure 2] FIG. 2 is a schematic structural diagram of a core in a certain nuclear power plant. [Figure 3] FIG. 3 is a schematic structural diagram of a pre-installed magnetic circuit component in the present invention. [Figure 4] FIG. 4 is a schematic structural diagram of the fault detection system for a generator core provided by the present invention.
Modes for Carrying Out the Invention
[0028] Here, in order to more clearly understand the technical features, objects, and effects of the present invention, the specific embodiments of the present invention will be described in detail with reference to the drawings.
[0029] It should be noted that the flowchart shown in the diagram is merely an illustrative example and does not necessarily have to include all content and operations / steps, nor must they be performed in the order they are shown. For example, some operations / steps may be broken down, and others may be combined or partially combined. Therefore, the actual order of execution can be changed depending on the situation.
[0030] The block diagrams shown in the figures represent only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.
[0031] Refer to Figure 1. The present invention provides a method for detecting a fault in a generator core to determine whether or not a fault exists at a suspected fault location in the generator core. The method includes steps S1, S2, and S3.
[0032] Step S1 includes constructing a measurement magnetic circuit by installing a local magnetic circuit at the suspected fault location.
[0033] In some embodiments, installing a local magnetic circuit at the suspected fault location in step S1 includes constructing a measuring magnetic circuit by connecting the gear teeth on both sides adjacent to the suspected fault location using pre-installed magnetic circuit components 2. Specifically, as shown in Figure 2, for example, if the suspected fault location 111 is located on a gear tooth 11b or on the radial yoke portion of the gear tooth 11b, then pre-installed magnetic circuit components 2 can be installed on the gear teeth 11a and 11c located on both sides adjacent to the gear tooth 11b. Note that gear teeth refer to the protruding parts on the gear used for meshing.
[0034] In some embodiments, as shown in Figure 2, the pre-installed magnetic circuit component 2 includes a magnetic circuit component body 21 and an excitation winding 22 provided on the magnetic circuit component body 21 to supply magnetic field energy to the measuring magnetic circuit. The two contact surfaces of the magnetic circuit component body 21 are in close contact with the surfaces of the gear teeth on both sides of the suspected fault location.
[0035] Furthermore, the smaller the effective cross-sectional area of the measuring magnetic circuit, the easier and more rapidly the measuring magnetic circuit will saturate. However, if the measuring magnetic circuit saturates too rapidly, the core will heat up rapidly, affecting the measurement accuracy. Also, the maximum effective cross-sectional area of the measuring magnetic circuit is limited by the area of the tooth tip plane of the gear teeth. To avoid the measuring magnetic circuit saturating too rapidly during measurement, in some embodiments, the magnetic circuit component body 21 may be a C-shaped column, as shown in Figure 3. This C-shaped column includes a transverse beam 211 and first and second side columns 212 and 213 extending outward from both ends of the transverse beam 211. In addition, the excitation winding 22 can be wound around the first side column 212. The effective cross-sectional areas of the transverse beam 211, the first side column 212 and the second side column 213 are greater than or equal to the tooth tip area of the gear teeth. Preferably, the end faces of the first and second side columns 212 and 213 coincide with the tooth tip plane of the gear teeth.
[0036] In this embodiment, the role of the pre-installed magnetic circuit component 2 is to reduce the excitation power required when detecting a core fault by constructing a measuring magnetic circuit with a relatively small effective cross-sectional area and magnetic circuit. The specific principle is as follows.
[0037] Refer to Figure 3. In this invention, after constructing a measuring magnetic circuit using pre-installed magnetic circuit components 2, the circuit at the fault location corresponds to a coil with 1 turn. Furthermore, the parameters have the following relationships.
[0038]
number
[0039] S1 is the first excitation power, U1 is the first excitation voltage, f1 is the first frequency, wt is the gear tooth width, lt is the gear tooth length, B1 is the first magnetic induction strength, I1 is the first excitation current, lc is the core width of the magnetic circuit component body 21, hc is the core height of the magnetic circuit component body 21, ht is the gear tooth height, and H1 is the first magnetic field strength.
[0040] Refer to Figure 2. In related technologies, when measuring using the iron loss method, the parameters of the faulty circuit have the following relationship.
[0041]
number
[0042] S2 is the second excitation power, U2 is the second excitation voltage, f2 is the second frequency, lu is the effective length of the core, hy is the height of the core yoke, B2 is the second magnetic induction strength, I2 is the second excitation current, D1 is the outer diameter of the core, and H2 is the second magnetic field strength.
[0043] When the frequencies, magnetic induction strengths, and magnetic field strengths of both are the same (i.e., f1=f2, B1=B2, H1=H2), as is clear from equations (1) and (2), the ratio of power supply power between the method of the present invention and the iron loss method is as follows.
[0044]
number
[0045] In some embodiments, using a certain model as an example, D1 is 2.99m, the yoke height hy is 0.525m, lu is 6.4m, ht is 0.215m, lc is 0.232m, hc is 0.1m, wt is 0.058m, and lt is 0.1m. Substituting these values into equation (3), it can be seen that the ratio of power consumption between the method of the present invention and the iron loss method is 0.00032. In this embodiment, compared to the iron loss method, the present invention makes it possible to reduce the power consumption for measurement to 1 / 3125 of the original.
[0046] Furthermore, in this embodiment, since the excitation winding 22 and the faulty circuit form an electrical structure similar to that of a transformer, the input voltage and input current of the excitation winding 22 have the following relationship.
[0047]
number
[0048] U3 is the input voltage of the excitation winding 22, N is the number of turns of the excitation winding 22, and I3 is the input current of the excitation winding 22.
[0049] As is clear from equation (4), when the excitation voltage and excitation current are stable, the input voltage U3 of the excitation winding 22 and the number of turns N are directly proportional, and the input current I3 of the excitation winding 22 and the number of turns N are inversely proportional. Therefore, during measurement, the number of turns should be adjusted based on the output voltage and current of the measuring power supply. For example, the higher the output voltage of the measuring power supply, the more turns are required.
[0050] Step S2 includes exciting the measuring magnetic circuit to bring it to a predetermined saturation state and maintaining it for a predetermined time. The role of the excitation process is as follows: To bring the magnetic circuit where the suspected fault is located to a predetermined saturation state similar to that during measurement using the iron loss method. That is, to set the magnetic induction strength of the magnetic circuit to 1.4T. Furthermore, to match the induced voltage generated at the fault location with the induced voltage generated during measurement using the iron loss method. This makes the heat generated at the fault location the same as when measuring using the iron loss method.
[0051] In some embodiments, step S2 includes collecting the induced voltage at the suspected fault location and adjusting the input voltage of the excitation winding 22 having a predetermined frequency to adjust the induced voltage at the suspected fault location to be equal to a predetermined saturation voltage of the measuring magnetic circuit, and sustaining it for a predetermined time.
[0052] In some embodiments, the pre-installed magnetic circuit component 2 further includes a measuring coil 23 for measuring the induced voltage. The measuring coil 23 can be installed on the second side column 213. Accordingly, collecting the induced voltage at the suspected fault location in step S2 includes collecting the measured voltage of the measuring coil 23 and calculating the induced voltage at the suspected fault location based on the number of turns of the measuring coil 23 and the measured voltage. In some embodiments, both ends of the measuring coil 23 may be connected to a voltmeter to collect the measured voltage.
[0053] The faulty circuit corresponds to a coil with 1 turn and is wound around the same measuring magnetic circuit as the measuring coil; therefore, the equation for the induced voltage in step S2 is Us = Ut / N2 (4). In the equation, Us is the induced voltage, Ut is the measured voltage, and N2 is the number of turns of the measuring coil 23.
[0054] Similarly, since the faulty circuit corresponds to a coil with 1 turn, when the measuring magnetic circuit reaches a predetermined saturation state, the magnetic strength can be calculated using the formula B=U / (4.44*f*N*S), The formula for a predetermined saturation voltage, Ub = Bb * (4.44 * fb * St) (5), can be derived. In the formula, Ub is the predetermined saturation voltage, Bb is the predetermined saturation magnetic induction strength in the measuring magnetic circuit (generally set to 1.4T), 4.44 is the induced electromotive force coefficient, fb is the predetermined frequency, and St is the contact area between the magnetic circuit component body 21 and the gear teeth.
[0055] As is clear from the related data of the iron loss method, the fault circuit at the core fault location has the following relationship during measurement.
[0056]
number
[0057] Iff is the fault current during the iron loss test, Uff is the induced voltage at the fault location during the iron loss test, R is the resistance of the circuit at the fault location, f3 is the third frequency, B3 is the third magnetic induction strength (generally set to 1.4T), and Sy is the area of the core yoke (i.e., the effective cross-sectional area of the magnetic circuit).
[0058] From formula (6), the formula for the induced voltage at the fault location during iron loss testing, Uff = 4.44 * fff * B3 * Sy (7), can be obtained. In order to ensure that the induced voltage when the measuring magnetic circuit reaches a predetermined saturation state matches the induced voltage in the iron loss method, that is, to satisfy Ub = Uff, it can be seen from equations (5) and (7) that fb * St must be equal to fff * Sy. Here, since the measurement frequency in the iron loss method is generally 50 Hz, the predetermined frequency can be set from the formula fb = 50 * Sy / St. Sy is the cross-sectional area of the yoke.
[0059] As is clear from equation (5), a specific theoretical value for Ub can be obtained when Bb, f, and St are all specific values. As can be understood, accordingly, the control device can collect the measured voltage and calculate the induced voltage based on the induced voltage formula. The control device controls the induced voltage Us by adjusting the magnitude of the input voltage of the excitation winding 22. When the induced voltage Us becomes equal to Ub, it means that the measuring magnetic circuit has reached a predetermined saturation state, so the control device stops adjusting the input voltage of the excitation winding 22, holds it for a predetermined time, and then can perform step S3.
[0060] Step S3 includes collecting thermographic information of the measuring magnetic circuit and generating a fault determination result based on the thermographic information.
[0061] In some embodiments, generating a fault determination result based on thermographic information in step S3 includes the following: extracting temperature characteristics from the thermographic information to determine whether or not there is a region in the generator core within the measuring magnetic circuit where the temperature is higher than the fault temperature. If a region where the temperature is higher than the fault temperature exists, it means that a fault exists in that region, and the amount of heat generated in that region is greater than in other normal regions due to increased internal resistance, so it is determined that a fault exists in that region. On the other hand, if there is no region where the temperature is higher than the fault temperature, it means that the amount of heat generated in the generator core within the measuring magnetic circuit is uniform, so it is determined that there is no fault in the generator core.
[0062] Refer to Figure 4. The present invention further provides a generator core fault detection system for determining whether or not a fault exists at a suspected fault location in the generator core 1. The generator core fault detection system includes a pre-installed magnetic circuit component 2, an excitation unit 3, a thermographic acquisition unit 4, and a judgment unit 5.
[0063] The pre-installed magnetic circuit component 2 is used to construct the magnetic circuit for measurement.
[0064] The excitation unit 3 is used to excite the constructed measuring magnetic circuit, bring it to a predetermined saturation state, and maintain that state for a predetermined time.
[0065] The thermographic acquisition unit 4 is used to collect thermographic information of the measurement magnetic circuit.
[0066] The judgment unit 5 is used to generate a fault judgment result based on thermographic information.
[0067] In some embodiments, as shown in Figure 2, the pre-installed magnetic circuit component 2 includes a magnetic circuit component body 21, an excitation winding, and a measuring coil. The two contact surfaces of the magnetic circuit component body 21 are used for close contact and connection with the surfaces of the gear teeth on both sides of the suspected fault location. The excitation winding 22 and the measuring coil 23 are provided on the magnetic circuit component body 21, respectively. The excitation winding 22 is for supplying magnetic field energy to the measuring magnetic circuit. The measuring coil 23 is used to collect the induced voltage at the suspected fault location.
[0068] In some embodiments, the excitation unit 3 includes a high-frequency power supply, a voltage collector, and an excitation control unit.
[0069] The high-frequency power supply is a high-frequency power supply used to apply an input voltage to the excitation winding 22.
[0070] The voltage collector is a voltage collector for measuring the measurement voltage of the measuring coil 23. Furthermore, the voltage collector may also function as a voltmeter.
[0071] The excitation control unit is used to bring the measuring magnetic circuit to a predetermined saturation state and maintain it for a predetermined time by controlling the output voltage of the high-frequency power supply based on the measured voltage.
[0072] The present invention has at least the following beneficial effects: namely, it provides a method for detecting faults in a generator core. In this method, first, a local magnetic circuit is installed at the suspected fault location to construct a measuring magnetic circuit, and then the measuring magnetic circuit is excited. A low-power power supply can be used for the excitation process. Even in this case, the measuring magnetic circuit can be brought to a predetermined saturation state. After maintaining this state for a predetermined time, thermographic information of the measuring magnetic circuit is collected, and finally, a fault judgment result is generated based on the thermographic information. Compared to conventional iron loss methods, the present invention significantly reduces the power required for the measuring power supply, making it easily implementable within nuclear power plants and eliminating the need to transport large and heavy test equipment. Furthermore, this method is simple and efficient, and can accurately determine whether or not a fault location exists in the core. Therefore, the time, workload, and cost of iron loss testing can be effectively reduced.
[0073] To ensure that this is understood, the above embodiments merely represent preferred embodiments of the present invention and, although described in a relatively specific and detailed manner, this should not be interpreted as limiting the scope of the rights of the present invention. Furthermore, it should be noted that those skilled in the art may freely combine the above technical characteristics, and may make some modifications and improvements, provided that they do not depart from the concept of the present invention, and all of these fall within the scope of protection of the present invention. Accordingly, equivalent transformations and modifications made based on the claims of the present invention shall all fall within the scope of the claims of the present invention.
Claims
1. A method for detecting a generator core failure to determine whether or not a failure exists in a suspected fault location of the generator core, S1: A step of constructing a measuring magnetic circuit by installing a local magnetic circuit at the suspected fault location, S2: The step of energizing the measuring magnetic circuit to bring it to a predetermined saturation state and maintaining that state for a predetermined time, S3: Includes the step of collecting thermographic information of the measuring magnetic circuit and generating a fault determination result based on the thermographic information, The generator core has a plurality of gear teeth, which are radially projecting protrusions, and the suspected fault location is at least one of the plurality of gear teeth. In step S1, installing a local magnetic circuit at the suspected fault location includes connecting the gear teeth on both sides adjacent to the suspected fault location with pre-installed magnetic circuit components. The pre-installed magnetic circuit component includes a magnetic circuit component body and an excitation winding provided on the magnetic circuit component body for supplying magnetic field energy to the measuring magnetic circuit, and the two contact surfaces of the magnetic circuit component body are in close contact with the surfaces of the gear teeth on both sides of the suspected fault location. The method for detecting a fault in a generator core is characterized in that step S2 includes collecting the induced voltage at the suspected fault location and adjusting the input voltage of an excitation winding having a predetermined frequency to adjust the induced voltage at the suspected fault location to be equal to a predetermined saturation voltage of the measuring magnetic circuit, and maintaining this for a predetermined time.
2. The method for detecting a fault in a generator core according to claim 1, wherein the magnetic circuit component body includes a transverse beam and first and second side columns extending outward from both ends of the transverse beam, and the effective cross-sectional area of the transverse beam, the first side column and the second side column is greater than or equal to the tooth tip area of the gear teeth.
3. The aforementioned pre-installed magnetic circuit component further includes a measuring coil for measuring the induced voltage. Collecting the induced voltage of the suspected fault location in step S2 includes collecting the measured voltage of the measuring coil and calculating the induced voltage of the suspected fault location based on the number of turns of the measuring coil and the measured voltage. The formula for the induced voltage is Us = Ut / N2, The method for detecting a fault in a generator core according to claim 2, characterized in that Us is the induced voltage, Ut is the measured voltage, and N2 is the number of turns of the measuring coil in the formula.
4. In step S2, the formula for the predetermined saturation voltage is Ub = Bb * (4.44 * fb * St), The generator core fault detection method according to claim 3, characterized in that Ub is a predetermined saturation voltage, Bb is a predetermined saturation magnetic induction intensity in the measuring magnetic circuit, fb is the predetermined frequency, and St is the contact area between the magnetic circuit component body and the gear teeth.
5. The method for detecting a fault in a generator core according to any one of claims 1 to 4, wherein generating a fault determination result based on the thermographic information in step S3 includes extracting temperature characteristics from the thermographic information to determine whether or not there is a region in the generator core portion of the measuring magnetic circuit where the temperature is higher than the fault temperature, and if so, determining that there is a fault in the generator core, and if not, determining that there is no fault in the generator core.
6. A generator core fault detection system for determining whether or not a fault exists in a suspected fault location of the generator core, Pre-installed magnetic circuit components for constructing a magnetic circuit for measurement, An excitation unit for performing an excitation process on the constructed measuring magnetic circuit to bring the measuring magnetic circuit to a predetermined saturation state and maintaining it for a predetermined time, A thermographic acquisition unit for collecting thermographic information of the aforementioned measuring magnetic circuit, Includes a determination unit for generating a fault determination result based on the thermographic information, The aforementioned pre-installed magnetic circuit components include an excitation winding and a measuring coil. The excitation unit is, A high-frequency power supply for applying an input voltage to the excitation winding, A voltage collector for measuring the measurement voltage of the aforementioned measuring coil, A generator core fault detection system characterized by including an excitation control unit that controls the output voltage of the high-frequency power supply based on the measured voltage to bring the measuring magnetic circuit to a predetermined saturation state and maintain it for a predetermined time.