Generator stator winding diagnosis method, diagnosis device, and program

Abstract

To provide a generator stator winding diagnosis method, a diagnosis device, and a program capable of diagnosing the life of a generator without stopping the operation of the generator.SOLUTION: The present invention is a generator stator winding diagnosis method in which a computer acquires a partial discharge signal corresponding to a partial discharge occurring from a stator winding in a generator in operation, estimates an estimated breakdown voltage due to the partial discharge based on the partial discharge signal, and diagnoses deterioration of the stator winding by the estimated breakdown voltage estimated based on the partial discharge signal in a low frequency band.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a generator stator winding diagnosis method, a diagnosis device, and a program. [Background technology]

[0002] The stator windings of generators such as hydroelectric generators installed in hydroelectric power plants deteriorate over time, and the deterioration of the stator windings has been assessed by, for example, an insulation deterioration diagnosis during shutdown that uses an estimated breakdown voltage estimated based on the amount of partial discharge charge obtained by applying a voltage to a stopped generator using a voltage application device. However, insulation deterioration diagnosis during shutdown requires the generator to be temporarily stopped, which poses a problem in efficiency. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Central Research Institute of Electric Power Industry Report (Central Research Institute of Electric Power Industry Report) Report No. GD22031 "Validity Evaluation of Partial Discharge Diagnosis in Operation of Hydrogenerator Stator Windings - Potential Distribution and Partial Discharge Propagation Characteristics During Lightning Surge Intrusion" Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, overseas, diagnosis is carried out to grasp the aging deterioration trend of individual stator windings and discover winding abnormalities based on partial power generation signals corresponding to partial discharges generated in the stator windings of generators during operation.However, generator diagnosis overseas does not include diagnosis of the generator's lifespan.

[0005] An object of the present invention is to provide a generator stator winding diagnostic method, diagnostic device, and program that can diagnose the life of a generator without stopping the operation of the generator. [Means for solving the problem]

[0006] [1] One aspect of the present invention is a generator stator winding diagnosis method, in which a computer acquires partial discharge signals corresponding to partial discharges occurring in a stator winding of an operating generator, estimates an estimated breakdown voltage due to the partial discharge based on the partial discharge signals, and diagnoses deterioration of the stator winding using the estimated breakdown voltage estimated based on the partial discharge signals in a low-frequency band.

[0007] [2] In one aspect of the present invention, in the aspect [1], when the estimated breakdown voltage reaches a judgment voltage based on a voltage at which the stator winding reaches the end of its life, the stator winding is diagnosed as having reached the end of its life.

[0008] [3] One aspect of the present invention is the aspect [1], wherein the generator is a generator used for hydroelectric power generation.

[0009] [4] One aspect of the present invention is that, in the aspect [1], when the estimated breakdown voltage becomes equal to or lower than a switching threshold, the estimated breakdown voltage is estimated based on the partial discharge signal in a low frequency band.

[0010] [5] In one aspect of the present invention, in the aspect [1], the switching threshold is set based on the period of use of the generator.

[0011] [6] In order to solve the above-mentioned problems, one aspect of the present invention is a generator stator winding diagnostic device comprising: an acquisition unit that acquires partial discharge signals corresponding to partial discharges occurring in a stator winding of an operating generator; an estimation unit that estimates an estimated breakdown voltage due to the partial discharge based on the partial discharge signals; and a diagnosis unit that diagnoses deterioration of the stator winding using the estimated breakdown voltage estimated based on the partial discharge signals in a low-frequency band.

[0012] [7] In order to solve the above problem, one aspect of the present invention is a program that causes a computer to acquire a partial discharge signal corresponding to a partial discharge occurring in a stator winding of an operating generator, estimate an estimated breakdown voltage due to the partial discharge based on the partial discharge signal, and diagnose deterioration of the stator winding using the estimated breakdown voltage estimated based on the partial discharge signal in a low-frequency band. [Effects of the Invention]

[0013] According to the generator stator winding diagnosis method, diagnosis device, and program of the present invention, it is possible to accurately diagnose the life of a generator without stopping the operation of the generator. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram showing an example of an environment in which a generator stator winding diagnosis device 100 is used. [Figure 2] 4 is a flowchart showing an example of processing in the generator stator winding diagnosis device 100. [Figure 3] 10 is a graph showing an example of an aging deterioration characteristic model used in insulation deterioration diagnosis during shutdown and an example of aging change in estimated breakdown voltage obtained by the degradation diagnosis according to the embodiment. [Figure 4] FIG. 10 is a diagram showing an example of the change over time in the maximum discharge charge amount of the generator stator winding 11. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, a generator stator winding diagnostic method, diagnostic device, and program according to an embodiment will be described with reference to the drawings.

[0016] 1 is a diagram showing an example of an environment in which a generator stator winding diagnostic device 100 is used. The generator stator winding diagnostic device 100 of the embodiment diagnoses the deterioration and lifespan of a generator stator winding 11 in a hydroelectric generator 10 installed in a hydroelectric power plant, for example, and determines the occurrence of an abnormality. In the hydroelectric generator 10, for example, insulation performance deteriorates due to void growth inside the insulation of the generator stator winding 11. The generator stator winding diagnostic device 100 diagnoses deterioration caused by such deterioration in insulation performance.

[0017] An abnormality in the generator stator winding 11 does not necessarily occur in all of the multiple generator stator windings 11, but is a phenomenon that can suddenly occur in each individual generator stator winding 11. Examples of abnormalities in the generator stator winding 11 include wear on the coil surface, misalignment of the silicon steel plate in the iron core (iron core misalignment), iron core overheating, and contamination of the coil end.

[0018] The hydroelectric generator 10 is, for example, a water turbine generator equipped with a water turbine that rotates due to water flow. The hydroelectric generator 10 is an example of a generator. The generator stator windings 11 include a U-phase generator stator winding 11U, a V-phase generator stator winding 11V, and a W-phase generator stator winding 11W, respectively.

[0019] The hydroelectric generator 10 supplies the generated electric power to the power grid W via a bus C. The U-phase generator stator winding 11U, the V-phase generator stator winding 11V, and the W-phase generator stator winding 11W of the generator stator winding 11 of the hydroelectric generator 10 are connected to the power grid via a U-phase bus CU, a V-phase bus CV, and a W-phase bus CW, respectively.

[0020] A partial discharge detection device 20 is provided between the U-phase bus CU, V-phase bus CV, and W-phase bus CW and the generator stator winding diagnosis device 100. The partial discharge detection device 20 detects the amount of charge of partial discharge (hereinafter referred to as partial discharge charge amount) generated in the generator stator winding 11 of the operating hydroelectric generator 10. The partial discharge detection device 20 generates a partial discharge signal according to the detected amount of partial discharge charge and transmits it to the generator stator winding diagnosis device 100.

[0021] The partial discharge detection device 20 includes, for example, a coupling capacitor 30 and a detector 40. The coupling capacitor 30 includes a first coupling capacitor 31, a second coupling capacitor 32, and a third coupling capacitor 33. The detector 40 includes a first detector 41, a second detector 42, and a third detector 43.

[0022] A first coupling capacitor 31 and a first detector 41 are attached to the U-phase bus CU, and the first detector 41 is connected to the generator stator winding diagnosis device 100. Similarly, a second coupling capacitor 32 and a second detector 42, and a third coupling capacitor 33 and a third detector 43 are attached to the V-phase bus CV and the W-phase bus CW, respectively, and the second detector 42 and the third detector 43 are both connected to the generator stator winding diagnosis device 100.

[0023] The partial discharge detection device 20 generates a partial discharge signal based on the amount of partial discharge charge for each of the U, V, and W phases. The coupling capacitor 30 is installed, for example, at the lead end of the generator stator winding 11 close to the location where partial discharge occurs. Partial discharge occurs on the lead end side of the stator winding where the potential is equal to or higher than the partial discharge inception voltage. By installing the coupling capacitor 30 at the lead end of the generator stator winding 11, the amount of partial discharge charge can be detected effectively.

[0024] The detector 40 detects the partial discharge signal via the coupling capacitor 30. The partial discharge detection device 20 is equipped with a digitizer (not shown) that converts the partial discharge signal detected by the detector 40 from an analog signal to a digital signal. The digital signal is a signal whose measurement frequency band can be adjusted by a real digital filter built into the digitizer.

[0025] During operation of the hydroelectric generator 10, base noise and thyristor noise are superimposed on the partial discharge signal. In three-phase simultaneous partial discharge measurement during operation, for example, the partial discharge pattern is measured simultaneously for three phases to remove the thyristor noise. The detector 40 transmits the partial discharge signal from which the base noise and thyristor noise have been reduced or removed to the generator stator winding diagnosis device 100. The partial discharge signal is transmitted from the detector 40 to the generator stator winding diagnosis device 100 via, for example, an optical fiber, which suppresses the inclusion of inductive noise and prevents electric shock.

[0026] The generator stator winding diagnosis device 100 is installed in, for example, a hydroelectric power plant. The generator stator winding diagnosis device 100 includes, for example, a receiving device 110, an input / output device 120, a storage device 130, and a processing device 140. The receiving device 110 receives, for example, a partial discharge signal transmitted by the detector 40. The receiving device 110 is realized by, for example, a network card, a network adapter, or a network interface controller (NIC). The receiving device 110 receives the partial discharge signal transmitted by the detector 40 of the partial discharge detection device 20.

[0027] The input / output device 120 includes, for example, an input device 121 and an output device 122. The input device 121 is a device through which an operator operating the generator stator winding diagnosis device 100 performs input operations. The input device 121 is realized by, for example, a mouse, a keyboard, a touch panel, a trackball, a switch, a button, a joystick, a camera, an infrared sensor, a microphone, etc.

[0028] In this specification, the input device 121 is not limited to devices equipped with physical operation parts such as a mouse, keyboard, etc. For example, an example of the input device 121 also includes an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs this electrical signal to a control circuit.

[0029] The output device 122 is, for example, a display that displays various types of information. The output device 122 is realized by, for example, a liquid crystal display, a CRT (Cathode Ray Tube), an organic EL (Electroluminescence) display, etc. The output device 122 may be a desktop display or a tablet display.

[0030] The storage device 130 may be configured, for example, by a semiconductor memory device such as a hard disk drive (HDD), an optical disk, a flash memory, an electrically erasable programmable read-only memory (EEPROM), a random access read / write memory (RAM), or a read-only memory (ROM), or any combination of these storage media. The storage device 130 may be, for example, a non-volatile memory. The storage device 130 may also be a drive device externally attached to the generator stator winding diagnosis device 100.

[0031] The processing device 140 includes, for example, an acquisition unit 141, an estimation unit 142, and a diagnosis unit 143. The processing device 140 is realized by, for example, a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Some or all of the components of the processing device 140 may be realized by hardware such as an LSI (Large Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a GPU (Graphics Processing Unit), or may be realized by a combination of software and hardware.

[0032] The program may be stored in advance in a storage device such as an HDD or flash memory (which may be a storage device 130 equipped with a non-transitory storage medium), or may be stored in a removable storage medium (non-transitory storage medium) such as a DVD or CD-ROM, and installed by inserting the storage medium into a drive device.

[0033] The acquisition unit 141 acquires a partial discharge signal corresponding to the amount of partial discharge charge of partial discharge occurring in the stator winding of the generator during operation. The acquisition unit 141 acquires, for example, a partial discharge signal transmitted by the detector 40 in the partial discharge detection device 20 during operation of the hydroelectric generator 10. The partial discharge signal is a signal corresponding to partial discharge occurring in the generator stator winding 11 of the hydroelectric generator 10 during operation.

[0034] The estimation unit 142 estimates an estimated breakdown voltage according to the amount of partial discharge charge based on the partial discharge signal acquired by the acquisition unit 141. The estimation unit 142 estimates an estimated breakdown voltage applied to the generator stator winding 11, for example, based on the amount of partial discharge charge based on the partial discharge signal acquired by the acquisition unit 141. The estimation unit 142 estimates the estimated breakdown voltage from, for example, the entire frequency band, the high frequency band, or the low frequency band of the partial discharge signal.

[0035] The diagnosing unit 143 diagnoses the deterioration of the stator winding based on the estimated breakdown voltage estimated based on the partial discharge signal in the low frequency band, among the estimated breakdown voltages estimated by the estimating unit 142. The diagnosing unit 143 diagnoses the deterioration of the generator stator winding 11 based on the estimated breakdown voltage estimated by the estimating unit 142, for example.

[0036] For example, during periods when the deterioration of the generator stator winding 11 is not expected to progress very far, the partial discharge signal is small and the noise level detected at the power plant is relatively high (the S / N ratio of the partial discharge signal is low). Therefore, in order to perform diagnosis while avoiding noise, the diagnosis unit 143 selects a high-frequency band and diagnoses the deterioration of the generator stator winding 11 from changes over time in the partial discharge signal. When estimating the estimated breakdown voltage based on a partial discharge signal in the high-frequency band, there is a tendency for the amount of signal attenuation to increase during signal propagation from the location of deterioration or abnormality in the generator stator winding 11 to the measurement location. For this reason, the estimated breakdown voltage may be estimated by taking the amount of signal attenuation into consideration and making a correction according to the amount of attenuation, for example.

[0037] When diagnosing the deterioration of the generator stator winding 11, at a time when it is assumed that the deterioration of the generator stator winding 11 has not progressed much, the diagnosis may be performed in a manner other than a manner based on a partial discharge signal with a selected high frequency band. For example, the deterioration of the generator stator winding 11 may be diagnosed based on a partial discharge signal with an unrestricted frequency band. In this case, for example, the deterioration of the generator stator winding 11 may be diagnosed by estimating an estimated breakdown voltage, or the deterioration of the generator stator winding 11 may be diagnosed directly from the magnitude of the partial discharge signal without estimating an estimated breakdown voltage.

[0038] For example, at a time when it is assumed that the deterioration of the generator stator winding 11 has progressed, the partial discharge signal is sufficiently larger than the noise level, and the diagnosing unit 143 diagnoses the deterioration of the generator stator winding 11 based on an estimated breakdown voltage estimated based on the partial discharge signal in a low frequency band. Regarding the deterioration of the generator stator winding 11, the diagnosing unit 143 determines the life of the generator stator winding 11 based on an estimated breakdown voltage estimated based on the partial discharge signal in a low frequency band.

[0039] With regard to the diagnosis in the diagnosing unit 143, the storage device 130 stores the values ​​of the switching threshold and the judgment voltage. The switching threshold is a threshold for determining the timing to switch the frequency band of the partial discharge signal that estimates the estimated breakdown voltage for judging the deterioration of the generator stator winding 11 from the high frequency band to the low frequency band. The high frequency band and the low frequency band can be set as appropriate; for example, the high frequency band may be 35 kHz or higher, and the low frequency band may be 100 kHz.

[0040] When the estimated breakdown voltage exceeds the switching threshold, the diagnostic unit 143 estimates, based on the high frequency band of the partial discharge signal, an estimated breakdown voltage for determining deterioration of the generator stator winding 11. When the estimated breakdown voltage exceeds the switching threshold, the diagnostic unit 143 switches the frequency band of the partial discharge signal for estimating the estimated breakdown voltage for determining deterioration of the generator stator winding 11 from the high frequency band to the low frequency band.

[0041] The threshold voltage is a voltage that serves as a reference value for determining the life of the generator stator winding 11. When the estimated breakdown voltage exceeds the threshold voltage, the diagnosis unit 143 determines that the generator stator winding 11 has not reached the end of its life, and when the estimated breakdown voltage is equal to or less than the threshold voltage, the diagnosis unit 143 determines that the generator stator winding 11 has reached the end of its life. The switching threshold and the threshold voltage may be set to any values. The switching threshold and the threshold voltage may also be values ​​that vary under specific conditions.

[0042] Next, the processing in the generator stator winding diagnosis device 100 will be described. Fig. 2 is a flowchart showing an example of the processing in the generator stator winding diagnosis device 100. The processing by the generator stator winding diagnosis device 100 is performed, for example, at regular time intervals while the hydroelectric generator 10 is in operation. The partial discharge detection device 20 detects, for example, the amount of partial discharge charge generated from the generator stator winding 11 at regular time intervals, generates a partial discharge signal, and transmits it to the generator stator winding diagnosis device 100.

[0043] The generator stator winding diagnosis device 100 first acquires, by the acquisition unit 141, the partial discharge signal transmitted by the partial discharge detection device 20 and received by the receiving device 110 (step S101). Next, the estimation unit 142 calculates an estimated breakdown voltage based on the partial discharge charge amount corresponding to the partial discharge signal acquired by the acquisition unit 141 (step S103).

[0044] Next, the diagnosing unit 143 determines whether the estimated breakdown voltage previously calculated by the estimating unit 142 is equal to or less than the switching threshold value stored in the storage device 130 (step S105). If it is determined that the estimated breakdown voltage is equal to or less than the switching threshold value, the diagnosing unit 143 diagnoses the deterioration of the generator stator winding 11 using the estimated breakdown voltage estimated based on the partial discharge signal in the low frequency band (step S107).

[0045] Next, the diagnosing unit 143 determines whether the estimated breakdown voltage is lower than the determination voltage stored in the storage device 130 (step S109). If it is determined that the estimated breakdown voltage is lower than the determination voltage, the diagnosing unit 143 diagnoses that the generator stator winding 11 has reached the end of its life (step S111). In this way, the generator stator winding diagnosis device 100 ends the processing shown in FIG. 2.

[0046] If it is determined in step S105 that the estimated breakdown voltage exceeds the switching threshold, the diagnosing unit 143 diagnoses the deterioration of the generator stator winding 11 based on the estimated breakdown voltage estimated based on the partial discharge signal in the high frequency band (step S113). In this way, the generator stator winding diagnosis device 100 ends the processing shown in Fig. 2. If the diagnosing unit 143 determines in step S109 that the estimated breakdown voltage is equal to or greater than the determination voltage, the generator stator winding diagnosis device 100 simply ends the processing shown in Fig. 2.

[0047] Next, the effect of performing a degradation diagnosis based on an estimated breakdown voltage obtained by the generator stator winding diagnostic device 100 of the embodiment (hereinafter referred to as the embodiment degradation diagnosis) will be described. In explaining the effect of the embodiment degradation diagnosis, as a comparative example, an aspect of insulation degradation diagnosis during stoppage based on an estimated breakdown voltage estimated based on the amount of partial discharge charge obtained by applying voltage by a voltage application device to a hydroelectric generator 10 that is stopped and disconnected from the power grid W will also be described.

[0048] Figure 3 is a graph showing an example of the aging deterioration characteristic model used in insulation deterioration diagnosis during shutdown and the change over time in the estimated breakdown voltage obtained by the degradation diagnosis according to the embodiment. In insulation deterioration diagnosis during shutdown, the aging deterioration of the generator stator winding 11 is estimated by applying the estimated breakdown voltage to one of multiple minimum insulation breakdown time curves (hereinafter referred to as aging deterioration characteristic models) created in advance. The vertical axis of Figure 3 represents the value expressed as a percentage obtained by dividing the estimated breakdown voltage by the rated line voltage of the hydroelectric generator 10. The initial breakdown voltage at the start of operation in each of the multiple aging deterioration characteristic models is set to 70%.

[0049] As the aging degradation characteristic models, for example, a first aging degradation characteristic model MD1 to a third aging degradation characteristic model MD3 shown in Fig. 3 are created. In insulation degradation diagnosis during shutdown, for example, an aging degradation characteristic model that best matches the degradation level of the generator stator winding 11 calculated based on the amount of partial discharge charge is selected from a plurality of aging degradation characteristic models, and an estimated breakdown voltage corresponding to the degradation level of the generator stator winding 11 is plotted on the selected aging degradation characteristic model to predict the transition over time from the diagnosis year.

[0050] 3 shows the switching threshold TH and the judgment voltage JN used in the degradation diagnosis of the embodiment. The switching threshold TH corresponds to, for example, the estimated breakdown voltage immediately before the S / N ratio of the partial discharge signal becomes small and the estimated breakdown voltage can be adequately estimated from the partial discharge signal in the low frequency band. The estimated breakdown voltage that becomes the switching threshold TH may be set by actually measuring the noise level, or may be set in advance as an arbitrary constant. The switching threshold TH may be set to a value other than the estimated breakdown voltage, for example, it may be set to the usage period of the hydroelectric generator 10 instead of the estimated breakdown voltage.

[0051] Deterioration of the generator stator winding 11 is, for example, a phenomenon in which insulation performance regularly decreases due to normal operation of the hydroelectric generator 10. A determination voltage JN for determining the life of the generator stator winding 11 is set to, for example, a value equivalent to the dielectric strength required for operation of the hydroelectric generator 10, for example, 2E+1 (E: rated voltage).

[0052] In the degradation diagnosis of this embodiment, when the estimated breakdown voltage exceeds the switching threshold TH, the S / N ratio of the partial discharge signal is low, so the estimated breakdown voltage in the high frequency band is estimated based on the partial discharge signal in the high frequency band to evaluate the progression of degradation of the generator stator winding 11. Therefore, when the estimated breakdown voltage exceeds the switching threshold TH, the degradation of the generator stator winding 11 is diagnosed in the same manner as in the insulation degradation diagnosis during shutdown.

[0053] On the other hand, when the period of use of the hydroelectric generator 10 becomes longer and the deterioration of the generator stator winding 11 progresses so that the estimated breakdown voltage becomes equal to or less than the switching threshold value TH, the S / N ratio of the partial discharge signal increases, and it becomes possible to estimate the estimated breakdown voltage based on the partial discharge signal in the low frequency band. Therefore, in the degradation diagnosis of this embodiment, after the estimated breakdown voltage becomes equal to or less than the switching threshold value TH, the diagnosis unit 143 estimates the estimated breakdown voltage based on the partial discharge signal in the low frequency band, estimates the deterioration of the generator stator winding 11, and determines that the generator stator winding 11 has reached the end of its life when the estimated breakdown voltage becomes equal to the judgment voltage JN.

[0054] In the degradation diagnosis of the embodiment, the diagnosis unit 143 estimates the life of the generator stator winding 11 based on, for example, a breakdown voltage estimated based on a partial discharge signal in a low frequency band. To estimate the life of the generator stator winding 11, the diagnosis unit 143 plots, for example, the estimated breakdown voltage estimated based on the partial discharge signal in a low frequency band. The diagnosis unit 143 generates an approximation curve R based on each of the plotted points. The diagnosis unit 143 determines the timing at which the approximation curve R intersects with a determination voltage JN as the life of the generator stator winding 11. In the degradation diagnosis of the embodiment, the life of the generator stator winding 11 may be determined in this manner.

[0055] Here, an example of the discharge charge of the generator stator winding 11 will be described. Fig. 4 is a diagram showing an example of the change over time in the maximum discharge charge of the generator stator winding 11. For example, after the hydroelectric generator 10 starts to be used, the maximum discharge charge of the generator stator winding 11 repeatedly fluctuates up and down within a normal level range for a certain period of time. The normal level range is, for example, a range in which the maximum discharge charge is 10,000 pC or less.

[0056] During this time, the maximum discharge charge amount repeatedly fluctuates between an approximate upper limit and a lower limit, but by estimating the breakdown voltage based on the partial discharge signal in the high frequency band, it is possible to appropriately determine the deterioration or abnormality of the generator stator winding 11. Therefore, in this case, by estimating the breakdown voltage based on the partial discharge signal in the high frequency band, it becomes possible to manage the trend of the generator stator winding 11 by detecting the partial discharge charge amount.

[0057] Subsequently, as the period of use of the hydroelectric generator 10 progresses, the maximum discharge charge increases to a range exceeding the upper limit value that repeatedly fluctuates, and finally the maximum discharge charge exceeds the normal level. When the maximum discharge charge exceeds the normal level, the partial discharge signal is significantly attenuated when it propagates, making it difficult to calibrate the maximum discharge charge for partial discharge signals in the high-frequency band, and making it difficult to properly determine whether the generator stator winding 11 has deteriorated or is abnormal.

[0058] Therefore, when the maximum discharge charge exceeds the normal level, the breakdown voltage is estimated based on the partial discharge signal in the low frequency band, and the deterioration or abnormality of the generator stator winding 11 is judged, thereby enabling trend management of the generator stator winding 11. In this example, the upper limit of the range of the normal level of the maximum discharge charge (for example, 10,000 pC) may be set as the switching threshold.

[0059] Although the embodiments of the present invention have been described above with reference to the drawings, the generator stator winding diagnosis method, diagnosis device, and program are not limited to the above-described embodiments, and various modifications, substitutions, combinations, and / or design changes can be made without departing from the spirit and scope of the present invention.

[0060] For example, the generator in the above embodiment is a hydroelectric generator 10 installed in a hydroelectric power plant, but the generator may be a generator installed in other power plants, etc. The generator may be, for example, a thermal power generator installed in a thermal power plant, or a wind power generator installed in a wind power plant.

[0061] Although the generator stator winding diagnosis device 100 of the embodiment is installed inside a power plant, the generator stator winding diagnosis device may also be installed on a cloud or server installed outside the power plant. In this case, the generator stator winding diagnosis device may be configured to comprehensively perform deterioration diagnosis of generators in multiple power plants.

[0062] Furthermore, the effects of the above-described embodiments of the present invention are described as examples. Therefore, the embodiments of the present invention may also achieve other effects that a person skilled in the art can recognize from the description of the above-described embodiments in addition to the above-described effects. [Explanation of symbols]

[0063] 10 Hydroelectric Generator 11 (11U, 11V, 11W) phase generator stator winding 20 Partial discharge detection device 30(31~33) Coupling capacitor 40(41~43) Detector 100 Generator stator winding diagnostic device 110 Receiving device 120 Input / Output Devices 121 Input Device 122 Output Device 130 Storage device 140 Processing equipment 141 Acquisition Department 142 Estimation Department 143 Diagnostic Department C(CU,CV,CW) Bus bar JN judgment voltage MD1 First aging deterioration model MD2 Second aging characteristic model MD3 3rd aging characteristic model R trendline TH Switching Threshold W Power system

Claims

1. The computer Acquiring a partial discharge signal corresponding to a partial discharge occurring in a stator winding of an operating generator; Estimating an estimated breakdown voltage due to the partial discharge based on the partial discharge signal; diagnosing deterioration of the stator winding based on the estimated breakdown voltage estimated based on the partial discharge signal in a low frequency band; Generator stator winding diagnostic method.

2. When the estimated breakdown voltage reaches a judgment voltage based on a voltage at which the stator winding reaches the end of its life, the stator winding is diagnosed as having reached the end of its life. The generator stator winding diagnosis method according to claim 1 .

3. The generator is a generator used for hydroelectric power generation. The generator stator winding diagnosis method according to claim 1 .

4. When the estimated breakdown voltage becomes equal to or lower than a switching threshold, the estimated breakdown voltage is estimated based on the partial discharge signal in a low frequency band. The generator stator winding diagnosis method according to claim 1 .

5. The switching threshold is set based on the duration of use of the generator. The generator stator winding diagnosis method according to claim 4.

6. an acquisition unit that acquires a partial discharge signal corresponding to a partial discharge occurring in a stator winding of the generator during operation; an estimation unit that estimates an estimated breakdown voltage due to the partial discharge based on the partial discharge signal; a diagnosis unit that diagnoses deterioration of the stator winding based on the estimated breakdown voltage estimated based on the partial discharge signal in a low frequency band. Generator stator winding diagnostic device.

7. On the computer, Acquiring a partial discharge signal corresponding to a partial discharge occurring in a stator winding of an operating generator; Estimating an estimated breakdown voltage due to the partial discharge based on the partial discharge signal; diagnosing deterioration of the stator winding based on the estimated breakdown voltage estimated based on the partial discharge signal in a low frequency band; program.

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