Partial discharge measuring device, partial discharge measuring method, and partial discharge measuring system

Abstract

Embodiments provide a partial discharge measuring device, a partial discharge measuring method, and a partial discharge measuring system that can measure a measurement value related to partial discharge in a measurement object region with higher precision. A partial discharge measuring device of an embodiment detects partial discharge generated in a rotating electric machine that supplies or receives electric power via an insulated conductor, has a correction signal generating section, a sensor, a correction processing section, and a signal processing section. The correction signal generating section supplies a correction signal to a surface of an insulating layer of the insulated conductor. The sensor measures a physical quantity related to partial discharge. The correction processing section generates a correction coefficient using an output signal of the sensor when the correction signal is supplied. The signal processing section processes the output signal of the sensor based on the correction coefficient.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2022-0986852 (filed on June 15, 2022), the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to a partial discharge measurement device, a partial discharge measurement method, and a partial discharge measurement system. Background Technology

[0003] Partial discharge is a tiny discharge that occurs within the insulation layer of a rotating electrical machine when a voltage is applied to the stator coils. It was previously thought that even if this discharge occurred, it would not immediately affect the operation of the rotating machine. However, it is known that the insulation material itself will deteriorate to some extent due to partial discharge.

[0004] Therefore, measurements are performed using a partial discharge measuring device to prevent degradation from leading to insulation breakdown during operation. The reliability of rotating electrical machines is diagnosed through periodic measurements of partial discharge using a partial discharge measuring device.

[0005] It can be assumed that as the distance between the sensor of the partial discharge measurement device and the target area approaches, the measurement accuracy will further improve. However, for small-scale thermal power generation equipment, hydropower generation equipment, etc., the cables that act as conductors may be insulated from the rotating motor to the switchboard at a certain distance, or access to the rotating motor, which is already installed, may be obstructed, making it difficult to place the sensor close to the target area. Furthermore, due to the insulation of the conductor, it is difficult to directly measure the target area, and the measured value of partial discharge may vary depending on the insulation layer surrounding the conductor. Additionally, safer measurement procedures are required. Summary of the Invention

[0006] The problem to be solved by the present invention is to provide a partial discharge measuring device, a partial discharge measuring method, and a partial discharge measuring system that can measure partial discharge-related values ​​in the measurement target area with higher accuracy.

[0007] This partial discharge measurement device detects partial discharge generated within a rotating electric motor that receives or supplies power via an insulated conductor. It comprises a calibration signal generation unit, a sensor, a correction processing unit, and a signal processing unit. The calibration signal generation unit supplies a calibration signal to the surface of the insulating layer of the insulated conductor. The sensor measures physical quantities related to partial discharge. The correction processing unit uses the sensor's output signal when the calibration signal is supplied to generate a correction coefficient. The signal processing unit processes the sensor's output signal based on the correction coefficient. Attached Figure Description

[0008] Figure 1 This is a diagram showing a schematic structural example of the partial discharge measurement system according to this embodiment.

[0009] Figure 2 This is a block diagram representing a structural example of a measuring instrument.

[0010] Figure 3 This is a diagram illustrating an example of the configuration of the sensor and the potential-equivalent unit stored in the storage unit.

[0011] Figure 4 This is a diagram representing a configuration example of configuration mode 1.

[0012] Figure 5 It means Figure 4 The diagram shows the equivalent circuit of the measurement system in the configuration example.

[0013] Figure 6 This is a diagram showing examples of input items and input values ​​for each component of an equivalent circuit.

[0014] Figure 7 This is a diagram representing a configuration example of configuration mode 2.

[0015] Figure 8 It means Figure 7 The diagram shows the equivalent circuit of the measurement system in the configuration example.

[0016] Figure 9 This is a diagram showing examples of input items and input values ​​for each component of an equivalent circuit.

[0017] Figure 10 This is a flowchart of a modification process example related to this embodiment.

[0018] Figure 11 This is a flowchart of the formal measurements related to this embodiment.

[0019] Figure 12 This is a diagram illustrating an example of the configuration of the sensor and antenna relative to the conductor.

[0020] Figure 13 It means Figure 12 The diagram shows the equivalent circuit of the measurement system.

[0021] Figure 14 This is a diagram illustrating an example of the configuration of the sensor and the same potential component relative to the conductor.

[0022] Figure 15 This is a graph representing an example of measurement results. Detailed Implementation

[0023] The following is a reference to the appendix. Figure 1The partial discharge measurement system, partial discharge measurement device, and partial discharge measurement method according to embodiments of the present invention will be described in detail below. Furthermore, the embodiments shown below are examples of embodiments of the present invention, and the present invention is not to be construed as limited to these embodiments. In addition, in the figures referenced to this embodiment, the same or similar reference numerals are given to the same parts or parts having the same function, and sometimes repeated descriptions are omitted. Furthermore, sometimes the dimensions in the figures differ from the actual scale for ease of explanation, or a part of the structure is omitted from the figures.

[0024] (First Embodiment)

[0025] Figure 1 This is a diagram showing a schematic structural example of the partial discharge measurement system according to this embodiment. Figure 1 The image shows a schematic vertical cross-sectional view of the rotary motor 10. (See image below.) Figure 1 As shown, the partial discharge measurement system 1 is a system capable of measuring partial discharge generated within the rotating motor 10, and for example, includes the rotating motor 10 and the partial discharge measurement device 20.

[0026] The rotating motor 10 is, for example, a water turbine generator, which generates electricity by rotating a rotor 2 mechanically connected to the rotating shaft of a water turbine. The partial discharge measuring device 20 is a device capable of correcting measurement signals and measuring partial discharges within the rotating motor 10. That is, the partial discharge measuring device 20 is a device capable of correcting measurement signals at locations far from the object being measured.

[0027] like Figure 1 As shown, the rotating electric motor 10, for example, has a rotor 2, a stator 3, insulated conductors 4, a frame 5, and a conductor protective cover 6. The rotor 2 rotates around a rotating shaft M10 mechanically connected to a water turbine. A predetermined stator coil is wound on the stator 3. More specifically, the stator coil is electrically connected to the conductor 4 in a state of being inserted into the stator 3.

[0028] Conductor 4 is, for example, a three-phase (U, V, W phase) conductor cable, connected to an inverter or distribution panel. The surface of the conductor cable of conductor 4 is insulated by covering it with an insulator. Furthermore, this embodiment uses a generator as an example, but is not limited to this. For example, the rotating motor 10 can be rotated by supplying power from a three-phase (U, V, W phase) AC cable. That is, the rotating motor 10 rotates by receiving power through the insulated conductor 4. In this case, the partial discharge measuring device 20 can also detect partial discharge within the rotating motor 10.

[0029] The frame 5 encloses the rotor 2, stator 3, and conductor protection cover 6. The frame 5 is sometimes referred to as a wind tunnel. The conductor protection cover 6 is positioned within the frame 5, vertically below the conductor 4. This conductor protection cover 6 is fixed to the frame 5 and supports the sensor 30.

[0030] The conductor protective cover 6 is made of, for example, a metallic mesh material and is connected to a predetermined low potential, such as ground potential. This prevents noise signals from entering the sensor 30. Furthermore, during operation, field workers may sometimes enter the area around the stator 3 inside the housing 5. In this case, it also prevents field workers from contacting high-voltage parts inside the housing 5. Thus, by placing the conductor protective cover 6 vertically below the conductor 4 and supporting the sensor 30 with the conductor protective cover 6, noise signals can be prevented from entering the sensor 30, and field workers can be prevented from contacting high-voltage parts. Furthermore, as will be described later, when a correction signal corresponding to partial discharge is being generated, even if, for example, a field worker accidentally enters the housing 5, electric shock due to the correction signal can be reliably prevented. In this embodiment, the case where the conductor protective cover 6 is placed vertically below the conductor 4 is illustrated, but the conductor protective cover 6 only needs to prevent field workers from contacting the conductor 4; it only needs to be placed around the conductor. Specifically, if a passage for field workers to enter is provided vertically above conductor 4, a conductor protective cover 6 can also be provided vertically above conductor 4 between the passage and conductor 4. If a passage for field workers to enter is provided on the left or right side of conductor 4, a conductor protective cover 6 can also be provided on the left or right side of conductor 4 between the passage and conductor 4. Furthermore, if the rotary motor 10 is a small rotary motor, such as one in which field workers cannot enter the interior of the frame, the conductor protective cover 6 can be provided to surround conductor 4, or it can be provided on the left or right sides of conductor 4 to prevent contact with conductor 4.

[0031] In this rotating electric motor 10, the stator 3 rotates along with the turbine, generating an alternating current in the coils of the stator 3. This alternating current is supplied to an inverter or switchboard via the conductor 4.

[0032] The partial discharge measurement device 20 includes a sensor 30, a potential-equivalent unit 40, a signal generation unit 50, a measuring device 60, a display unit 70, and an operation unit 80. As described above, the sensor 30 is disposed on the conductor protective cover 6. The sensor 30 is a sensor that non-contactly measures physical quantities related to partial discharge generated within the rotating motor 10, and functions as a partial discharge measurement sensor. For example, the sensor 30 is a sensor that generates a detection signal corresponding to the current flowing through the conductor 4. More specifically, the sensor 30 is, for example, a current sensor that is electrostatically capacitively coupled to the conductor 4 in space. In addition, the sensor 30 in this embodiment is an electrostatically capacitively coupled sensor, but it is not limited to this. For example, any sensor capable of non-contactly measuring the conductor 4 is acceptable, such as a current sensor such as a CT (Current Transformer). Furthermore, the sensor 30 in this embodiment is a current sensor, but it is not limited to this. For example, any sensor capable of non-contactly measuring physical quantities related to partial discharge with respect to the conductor 4 is acceptable, such as a voltage measurement sensor.

[0033] The potential-equivalent portion 40, made of materials such as aluminum, is a potential-equivalent body that conducts correction signals to the surface of the insulating layer of the insulated conductor 4. That is, the potential-equivalent portion 40 is disposed around the insulating layer of the insulated conductor 4. The surface of the potential-equivalent portion 40 opposite to the conductor 4 can be either a point-like area or a surface-like area. Furthermore, it does not need to be in complete contact with the periphery of the insulating layer of the insulated conductor 4; partial contact is also possible. In this way, the potential-equivalent portion 40 can be disposed corresponding to the outer surface of the insulated conductor 4.

[0034] The signal generation unit 50 generates a correction signal corresponding to the partial discharge. This correction signal is, for example, a pulse-like signal supplying a specified charge, such as several hundred picocoulombs, within a specified time, such as a few nanoseconds. For example, the correction signal is set based on a representative value of the frequency of the partial discharge of the object being measured. Thus, the correction signal is configured to have a frequency corresponding to the partial discharge of the object being measured.

[0035] Furthermore, the same potential section 40 and the signal generation section 50 are used to acquire data for signal correction before the formal measurement. Therefore, during the formal measurement, the same potential section 40 and the signal generation section 50 can be detached from the partial discharge measurement system 1. In addition, the same potential section 40 and the signal generation section 50 in this embodiment constitute a calibration signal generation section 50a.

[0036] The measuring device 60 controls each structure of the partial discharge measuring device 20 and measures physical quantities related to partial discharge using the detection signal from the sensor 30. The measuring device 60 can correct the detection signal from the sensor 30 using a correction signal generated by the signal generation unit 50. Further details of the measuring device 60 will be described later.

[0037] The display unit 70 is, for example, a monitor. This display unit 70 can, for example, display the equivalent circuit diagram of the measurement system, the input items of the equivalent circuit diagram, the measurement results, and the determination results for partial discharge.

[0038] The operation unit 80 may consist of, for example, a keyboard, a mouse, etc. The operation unit 80 may be used to set circuit parameters of the measurement system of the partial discharge measurement device 20, for example.

[0039] Figure 2 This is a block diagram showing an example of the structure of the measuring device 60. The measuring device 60 includes an AD conversion unit 602, a storage unit 604, a control processing unit 606, and an input / output unit 608.

[0040] The AD converter 602 converts the detection signal output by the sensor 30 into a digital output signal. The AD converter 602 may be configured to include an amplifier circuit.

[0041] The storage unit 604 is implemented, for example, by semiconductor memory elements such as RAM (Random Access Memory), flash memory, hard disk, optical disk, etc. This storage unit 604 stores the digital output signals generated by the AD converter 602 and the control processing unit 606. Furthermore, the storage unit 604 stores information required for processing the measuring instrument 60, such as the program and equivalent circuit information.

[0042] The control processing unit 606 is configured, for example, to include a CPU (Central Processing Unit). The control processing unit 606 performs control processing according to a program stored in the storage unit 604. That is, according to the program stored in the storage unit 100, the control processing unit 606 comprises a correction processing unit 610, a signal processing unit 612, and a decision processing unit 614.

[0043] The input / output unit 608 functions as an input / output interface. That is, the input / output unit 608 can input and output signals between the measuring instrument 60 and the signal generation unit 50, the display unit 70, and the operation unit 80.

[0044] The correction processing unit 610 uses the output signal of the sensor 30 when the correction signal generated by the signal generation unit 50 is supplied to the insulated conductor 4 to generate a correction coefficient. Further details of the correction processing unit 610 will be described later.

[0045] In the case of formal measurement, the signal processing unit 612 processes the digital output signal based on the output signal of the sensor 30 based on the correction coefficient generated by the correction processing unit 610. For example, the signal processing unit 612 multiplies the digital output signal by the correction coefficient to generate a measurement signal. This measurement signal corresponds to the amount of charge of the partial discharge. In other words, the correction coefficient is generated in a way that is equivalent to the amount of charge of the partial discharge. In addition, the signal processing unit can perform noise reduction processing using a low-pass filter or the like. Alternatively, the digital output signal can be made to correspond to the rotation cycle of the rotary motor 10, and the digital output signal can be summed for each rotation cycle.

[0046] The signal processing unit 612 stores the measurement signal in the storage unit 604. Furthermore, the signal processing unit 612 can cause the display unit 70 to display the measurement signal in a time sequence via the input / output unit 608. Thus, the operator can observe physical quantities related to partial discharge.

[0047] The determination processing unit 614 determines the state of the rotary motor 10 based on the measurement signal generated by the signal processing unit 612. For example, if the absolute value of the measurement signal generated by the signal processing unit 612 exceeds a predetermined threshold, it is determined to be abnormal. In the case of determining an abnormality, the determination processing unit 614 can cause the display unit 70 to display a display indicating the abnormality via the input / output unit 608.

[0048] Furthermore, as another example of the determination process, the maximum value of the measurement signal corresponding to more than 10 pulse-like partial discharges per second is defined as the maximum discharge charge. The determination processing unit 614 obtains the pulse peak value corresponding to more than 10 partial discharges per second based on the measurement signal generated by the signal processing unit 612, and determines an anomaly if the maximum value of the peak value exceeds a predetermined threshold. In the case of an anomaly, the determination processing unit 614 can display an anomaly on the display unit 70 via the input / output unit 608. Furthermore, a resolving correction process can be performed. Before the diagnosis by the determination processing unit 614, a correction signal simulating a known discharge signal is introduced into the first measurement area 9 (described later), clarifying the relationship with characteristic quantities such as the peak value of the output signal from the sensor 30. Based on this resolving correction process, the discharge charge during diagnosis in the formal measurement can be calculated by inversely deducing the characteristic quantities of the acquired signal.

[0049] use Figures 3 to 9 This section describes a detailed processing example of the correction processing unit 610. Figure 3This diagram illustrates an example of the configuration modes of the sensor 30 and the potential-equivalent unit 40 stored in the storage unit 604. Configuration mode 1 is a configuration mode in which the sensor 30 is directly below the potential-equivalent unit 40. Configuration mode 2 is a configuration mode in which the sensor 30 is not directly below the potential-equivalent unit 40. These configuration modes of the sensor 30 and the potential-equivalent unit 40 correspond to two configuration modes, for example.

[0050] Therefore, the equivalent circuit of the measurement system of the partial discharge measurement device 20 is as described later. Figure 5 , Figure 8 The example shown is two modes. The correction processing unit 610 causes the display unit 70 to display... Figure 3 The configuration example shown is illustrated in the diagram. The operator selects the configuration mode via the operation unit 80.

[0051] Figure 4 This diagram illustrates a configuration example of configuration mode 1. The first measurement region 9 is the region of the same potential section 40 where the calibration signal is input. The second measurement region 8 is a hypothetical region that serves as the measurement object of the sensor 30 when the same potential section 40 and the insulator are removed. That is, the second measurement region 8 is a hypothetical measurement point in direct contact with the conductor 4, and is a region within the insulation layer. The first measurement region 9 is the region on the surface of the insulation layer of the conductor 4, which is covered by the inner surface of the same potential section 40. The correction processing unit 610 uses the measurement signal supplied with the calibration signal to the first measurement region 9 to generate a correction coefficient based on the correspondence between the measurement signal and the current flowing through the second measurement region 8. In other words, in this measurement system, the partial discharge generated within the rotating motor 10 corresponds to the signal measured in the second measurement region 8.

[0052] Figure 5 It means Figure 4 The diagram shows the equivalent circuit of the measurement system in the example configuration. Figure 6 This is a diagram illustrating an example of the input items and values ​​for each component of an equivalent circuit. This equivalent circuit is an example, and the equivalent circuit and numerical examples are not limited to this one.

[0053] For example, when configuration mode 1 is selected, the correction processing unit 610 causes the display unit 70 to display. Figure 5 The equivalent circuit shown and Figure 6 The input items are shown. The operator acts as... Figure 6 Input values ​​corresponding to the configuration values ​​shown in the input items. These values ​​are stored in the storage unit 604 once set, so they do not need to be set again without changing the measurement system.

[0054] like Figure 4As shown, generator inductance 10z is the inductance within the rotating motor 10; electrostatic capacitance 11 is the electrostatic capacitance of the insulating layer surrounding conductor 4; electrostatic capacitance 12 is the electrostatic capacitance between conductor 4 and sensor 30; electrostatic capacitance 13 is the electrostatic capacitance between sensor and shielding; electrostatic capacitance 14 is the electrostatic capacitance of the coaxial cable constituting conductor 4; and inductance 15 is the inductance of the coaxial cable constituting conductor 4. Impedance 16 is the detection impedance of sensor 30.

[0055] The values ​​of each element in these equivalent circuits are known or can be calculated using measured values. The elements of impedance Z and electrostatic capacitance 12 are known. Furthermore, for example, electrostatic capacitance 11 can be calculated using the imaginary distance d between the second measurement region 8 and the sensor 30, the imaginary area S of the second measurement region 8, the relative permittivity εr of the insulating layer, and the permittivity ε0 of vacuum, by ε0εr×S / d. Additionally, in this embodiment, the generator inductance 10z is neglected in the calculation because it has a small impact on the impedance of the measurement system.

[0056] When a calibration signal is supplied from the first measurement region 9 of the same potential section 40, a potential V1 is generated at the measurement point 17. As described above, since the impedance 16 is the detection impedance of the sensor 30, the potential V1 of the measurement point 17 when the calibration signal is supplied corresponds to the signal value of the measurement signal of the sensor 30.

[0057] As described above, the values ​​of each element in the equivalent circuit are known. Therefore, the ratio of the generated potential v0 in the second measurement region 8 to the insulating surface potential v0' in the first measurement region 9, i.e., the attenuation characteristic v0' / v0, is calculated as 1 / k1 = 0.909. At this time, the insulating surface potential v0' of the first measurement region 9 corresponds to a specified amount of charge per specified time, for example, every few nanoseconds, for example, several hundred picocoulombs. Thus, by multiplying the potential V1 at measurement point 17 as the reciprocal of the attenuation characteristic by the coefficient k1 = v0 / v0', a correction calculation corresponding to the specified amount of charge can be performed. Figure 6 As shown, for example, when the electrostatic capacitance 11 of the insulation layer of conductor 4 is set to 10pF, the electrostatic capacitance 12 between conductor 4 and sensor 30 is set to 1pF, the electrostatic capacitance 13 between sensor 30 and shielding is set to 1.5pF, the electrostatic capacitance 14 of coaxial cable is set to 2.04nF, the inductance of coaxial cable is set to 5.1μH, and the detection impedance of sensor 30 is set to 50Ω, 1 / k1 = 0.901. Thus, the correction processing unit 610, based on... Figure 6 The input values ​​shown are automatically calculated to obtain the coefficient k1.

[0058] For example, if the electrostatic capacitance 11 of the insulation layer of conductor 4 is set to 200pF, the electrostatic capacitance 12 between conductor 4 and sensor 30 is set to 1pF, the electrostatic capacitance 13 between sensor 30 and shielding is set to 1.5pF, the electrostatic capacitance 14 of coaxial cable is set to 2.04nF, the inductance of coaxial cable is set to 4.97μH, and the detection impedance of sensor 30 is set to 50Ω, then 1 / k1 = 0.995. In this embodiment, when the attenuation characteristic value is sufficiently close to 1, the correction process is omitted because the impact on the calibration accuracy is small. For example, when the absolute value of the attenuation characteristic value is between 0.990 and 1.010, the correction process is omitted.

[0059] Thus, the correction processing unit 610 actually causes the correction signal to flow through the first measurement region 9, and is measured by the sensor 30 via the actual measurement system. Furthermore, since the equivalent circuit of the measurement system is known, the correction processing unit 610 uses the values ​​of each element of the equivalent circuit to set the correspondence between the measured value of the sensor 30 and the measured value of the second measurement region 8 as a coefficient k1 and performs calculations. As a result, the signal processing unit 612 sets the measurement signal as the measurement current I8 = k1 × V1 and performs calculations. k1 is the correction coefficient. It can be seen that the measurement signal generated by the signal processing unit 612 corresponds to the current value I8 of the measurement current measured in the second measurement region 8. That is, the measurement signal generated by the signal processing unit 612 becomes a value equivalent to the charge amount of partial discharge within a specified time. In addition, in this embodiment, the measurement signal is described as a current, but it is not limited to this. As described above, the measurement signal only needs to correspond to the charge amount of partial discharge measured in the second measurement region 8, for example, it can also be a voltage signal, or it can also be a charge signal for each specified time.

[0060] Figure 7 This diagram illustrates a configuration example for configuration mode 2. The first measurement area 9 is the area of ​​the same potential section 40 for inputting calibration signals. The second measurement area 8 is the area that the sensor 30 measures when the same potential section 40 and the insulator are removed. That is, the second measurement area 8 and the sensor 30 are separated.

[0061] Figure 8 It means Figure 7 The diagram shows the equivalent circuit of the measurement system in the example configuration. An inductor 18 is added, running from the same potential section 40 to a position directly above the sensor 30.

[0062] Figure 9 This is a diagram illustrating an example of the input items and values ​​for each component of an equivalent circuit. This equivalent circuit is just one example; equivalent circuits and numerical examples are not limited to this one.

[0063] As described above, the signal processing unit 612 uses information from the equivalent circuit and, based on the relationship between the correction signal and the potential V1, calculates the current value I8 of the measurement signal as k1b × V1. k1b is a correction coefficient. In this way, the measurement signal generated by the signal processing unit 612 is equivalent to the actual charge of the partial discharge, for example, the charge of the partial discharge is consistent with the physical dimensions.

[0064] like Figure 9 As shown, for example, when the electrostatic capacitance 11 of the insulation layer of conductor 4 is set to 10pF, the electrostatic capacitance 12 between conductor 4 and sensor 30 is set to 1pF, the electrostatic capacitance 13 between sensor 30 and shielding is set to 1.5pF, the electrostatic capacitance 14 of coaxial cable is set to 2.04nF, the inductance of coaxial cable is set to 5.1μH, the detection impedance of sensor 30 is set to 50Ω, and the inductance 18 is set to 5pH, then 1 / k1b = 1.100.

[0065] For example, if the electrostatic capacitance 11 of the insulation layer of conductor 4 is set to 200pF, the electrostatic capacitance 12 between conductor 4 and sensor 30 is set to 1pF, the electrostatic capacitance 13 between sensor 30 and shielding is set to 1.5pF, the electrostatic capacitance 14 of coaxial cable is set to 2.04nF, the inductance of coaxial cable is set to 5.1μH, the detection impedance of sensor 30 is set to 50Ω, and the inductance 18 is set to 5pH, then 1 / k1b = 1.001. As described above, for example, when the absolute value of the attenuation characteristic value is between 0.990 and 1.010, the correction process is omitted.

[0066] The above describes the structure of this embodiment. The following describes a processing example. Figure 10 This is a flowchart of a modification process example related to this embodiment. For example... Figure 10 As shown, the operator, for example, configures the sensor 30 onto the conductor protective cover 6 (see reference). Figure 1 ), and the same potential part 40 is disposed in the frame 5 (step S100).

[0067] Next, the selection screen displayed on the display unit 70 is processed by the correction processing unit 610 (see reference). Figure 3 The operator selects configuration mode 1 via the operation unit 80 (step S102). Next, the correction processing unit 610 causes the display unit 70 to display the equivalent circuit of configuration mode 1 and the input items corresponding to the equivalent circuit (see reference). Figure 5 , Figure 6 The operator inputs the configuration values ​​corresponding to each item via the operation unit 80 (step S104). These configuration values ​​are stored in the storage unit 604.

[0068] Next, in response to the input of the calibration start signal from the operator via the operation unit 80, the signal generation unit 50 generates a calibration signal and outputs a known calibration signal from the first measurement area 9 of the same potential unit 40. At this time, the output signal of the sensor 30 is converted into a digital output signal by the AD conversion unit 608 and supplied to the correction processing unit 610 (step S106).

[0069] Next, the correction processing unit 610 calculates the correction coefficient k1 based on the input items and digital output signals corresponding to the equivalent circuit (step S106). In this way, the correction processing unit 610 actually makes the correction signal flow through the first measurement area 9, and the sensor 30 measures it through the actual measurement system. Based on the measurement signal V1 of the sensor 30, the actual correction signal, and the values ​​of each component of the equivalent circuit, the current value of the second measurement area 8 and the measurement signal V1 are calculated as the correction coefficient k1.

[0070] Figure 11 This is a flowchart of the formal measurements related to this embodiment. (For example...) Figure 11 As shown, the operator starts the measurement of the measuring device 60 via the operation unit 80 (step S200).

[0071] Next, the signal processing unit 612 generates a measurement signal based on the correction coefficient k1 generated by the correction processing unit 610 and the digital output signal based on the output signal of the sensor 30 (step S202).

[0072] Next, the signal processing unit 612, via the input / output unit 608, causes the display unit 70 to display the generated measurement signal in a time sequence (step S204). In this way, the signal processing unit 612 generates the measurement signal based on the correction coefficient k1 and displays it in a time sequence on the display unit 70. Thus, the operator can monitor a measurement signal equivalent to the current measured in the second measurement region 8 inside the insulation layer of the conductor 4.

[0073] As explained above, according to this embodiment, the same-potential section 40 constituting the calibration signal generation unit 50a and the signal generation unit 50 supply a calibration signal to the insulated conductor 4. The correction processing unit 610 uses the output signal of the sensor 30 when the calibration signal is supplied to generate correction coefficients k1 and k1b. Furthermore, during actual measurement, the signal processing unit 612 processes the output signal of the sensor 30 based on the correction coefficients k1 and k1b. As a result, the measurement signal generated by the signal processing unit 612 can be proportional to the amount of partial discharge charge. Furthermore, since the correction processing unit 610 uses information from the equivalent circuit based on the positions of the same-potential section 40 and the sensor 30 relative to the insulated conductor 4 to generate correction coefficients k1 and k1b, the signal processing unit 612 can generate a measurement signal equivalent to the current corresponding to the partial discharge measured in the second measurement region 8 inside the insulation layer of the conductor 4.

[0074] (A variation of the first embodiment)

[0075] The partial discharge measurement system 1 of the modified example of the first embodiment differs from the partial discharge measurement system 1 of the first embodiment in that it uses an antenna 40a to supply a calibration signal to the conductor 4 in a non-contact manner instead of the same potential section 40. Hereinafter, the differences from the partial discharge measurement system 1 of the first embodiment will be explained.

[0076] Figure 12 This is a diagram illustrating an example of the configuration of sensor 30 and antenna 40a relative to conductor 4. Figure 13 It means Figure 12 The diagram shows the equivalent circuit of the measurement system. (See diagram for example.) Figure 12 As shown, an antenna 40a is used to supply a correction signal to conductor 4 without contact with conductor 4. In this case, the influence of the contact resistance with conductor 4 can be suppressed, and the correction coefficients can be calculated more stably. Figure 13 As shown, the correction processing unit 610 can calculate each correction coefficient by setting the electrostatic capacitance related to the antenna 40a as the electrostatic capacitance 11b. Furthermore, the antenna 40a and the signal generation unit 50 of this embodiment constitute a correction signal generation unit 50a.

[0077] (Second Implementation)

[0078] The partial discharge measurement system 1 of the second embodiment differs from the partial discharge measurement system 1 of the first embodiment in that it can also measure the attenuation rate depending on the length of the conductor 4. The differences from the partial discharge measurement system 1 of the first embodiment will be explained below.

[0079] Figure 14 This diagram illustrates an example of the configuration of the sensor 30 and the same potential section 40 relative to the conductor 4. (See diagram for example.) Figure 14 As shown, by changing the positions of sensor 30 and the same potential section 40 relative to conductor 4, a calibration signal is supplied to conductor 4, and a measurement signal is measured.

[0080] Figure 15 This is a graph showing an example of the measurement results. The horizontal axis represents the distance between the potential-equivalent unit 40 and the sensor 30, and the vertical axis represents the intensity of the measurement signal. This data is stored in the storage unit 604.

[0081] The correction processing unit 610 calculates the attenuation rate corresponding to the distance between the same potential unit 40 and the sensor 30, and reflects it in the correction coefficients k1 and k1b. Therefore, the information about the distance between the same potential unit 40 and the sensor 30 can be reflected in the measurement signal, further improving measurement accuracy.

[0082] Several embodiments of the present invention have been described, but these embodiments are merely illustrative and not intended to limit the scope of the invention. These new embodiments can be implemented in a wide variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope or spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents.

[0083] Label Explanation

[0084] 1: Partial discharge measurement system; 2: Rotor; 3: Stator; 4: Conductor; 5: Frame; 6: Conductor protective cover; 10: Rotating motor; 20: Partial discharge measurement device; 30: Sensor; 40: Potential unit; 40a: Antenna; 50: Signal generation unit; 50a: Calibration signal generation unit; 60: Measuring instrument; 70: Display unit; 80: Operation unit; 610: Correction processing unit; 612: Signal processing unit; 614: Judgment processing unit; k1, k1b: Correction coefficients.

Claims

1. A partial discharge measuring device for detecting partial discharge generated in a rotating electric motor that receives or supplies power via an insulated conductor, comprising: The calibration signal generation unit supplies a calibration signal to the surface of the insulating layer of the insulated conductor; Sensors that measure physical quantities related to the partial discharge; The correction processing unit generates a correction coefficient using the output signal of the sensor when the correction signal is supplied. as well as The signal processing unit processes the output signal of the sensor based on the correction coefficient.

2. The partial discharge measuring device as described in claim 1, wherein, The sensor is separated from the insulated conductor by an electrostatic capacitance in space; The correction signal generation unit has: The signal generation unit generates the correction signal; and The same potential section can be configured to correspond to the outer surface of the insulated conductor and supply the correction signal to the insulated conductor.

3. The partial discharge measuring device as described in claim 2, wherein, The correction processing unit generates the correction coefficient using information from the equivalent circuit, which is based on information related to the same potential section, the position of the sensor relative to the insulated conductor, and the measurement area inside the insulation layer of the insulated conductor.

4. The partial discharge measuring device as described in claim 3, wherein, The signal processing unit generates the sensor's output signal based on the correction coefficient, which serves as a measurement signal corresponding to the partial discharge measured in the measurement area.

5. The partial discharge measuring device as described in claim 4, wherein, The correction signal generation unit supplies the correction signal from the same potential unit at multiple locations on the insulated conductor; The correction processing unit generates the correction coefficient using the output signals of each of the sensors when the correction signal is supplied from the plurality of locations.

6. The partial discharge measuring device as described in claim 3, wherein, The correction processing unit causes the display unit to display input items related to the constituent elements of the equivalent circuit, and generates the correction coefficient based on the input values ​​corresponding to the input items.

7. The partial discharge measuring device as described in claim 6, wherein, The correction processing unit causes the display unit to display multiple different equivalent circuits and generates the correction coefficients corresponding to the operator's selection.

8. The partial discharge measuring device as described in claim 1, wherein, The correction processing unit sets the coefficient to 1 if the correction coefficient is within a specified range.

9. The partial discharge measuring device as described in claim 2, wherein, The signal generation unit generates electrical pulses of current as the correction signal; The correction processing unit generates the correction coefficient based on the effective value of the sensor's output signal when the electrical pulse is supplied.

10. The partial discharge measuring device as claimed in claim 1, wherein, The correction signal generation unit has: The signal generation unit generates the correction signal; and An antenna can be disposed on the outer surface of the insulated conductor to supply the correction signal to the insulated conductor in a non-contact manner.

11. A method for measuring partial discharge, detecting partial discharge generated in a rotating electric motor that supplies or receives power via an insulated conductor, comprising: In the supply process, a calibration signal is supplied to the surface of the insulating layer of the insulated conductor; The correction processing step uses the output signal of a sensor that is disposed in non-contact with the insulated conductor when the correction signal is supplied to it to generate a correction coefficient; and The signal processing step involves processing the output signal of the sensor based on the correction coefficient.

12. A partial discharge measurement system, comprising: A rotating electric motor, including stator coils and a rotor arranged within a frame; An insulated conductor is connected to the stator coil; A conductor protective cover, within the frame, is configured to surround at least a portion of the insulated conductor; A sensor, configured on the conductor side of the conductor shield, measures physical quantities related to partial discharge generated within the rotating motor; and The signal processing unit processes the output signal of the sensor; The conductor protective cover within the frame is connected to a specified low potential.

13. The partial discharge measurement system as described in claim 12, wherein, It also has a correction processing unit that generates a correction coefficient using the output signal of the sensor when a correction signal is supplied to the insulating conductor surface within the frame from the same potential unit; The correction processing unit generates correction coefficients using information from the equivalent circuit, which is based on information related to the same potential unit, the position of the sensor relative to the insulated conductor, and the measurement area inside the insulation layer of the insulated conductor. The signal processing unit generates the sensor's output signal based on the correction coefficient, which serves as a measurement signal corresponding to the partial discharge measured in the measurement area.

14. A partial discharge measuring device for detecting partial discharge generated in the stator coils of a generator, the generator having a rotating motor including the stator coils and a rotor disposed within a frame, an insulated conductor connected to the stator coils, and a conductor protective cover disposed within the frame and connected to a predetermined low potential, thereby surrounding at least a portion of the insulated conductor, the partial discharge measuring device having: A sensor, configured on the conductor side of the conductor shield, measures physical quantities related to the partial discharge; and The signal processing unit processes the output signal of the sensor.

15. The partial discharge measuring device as described in claim 14, wherein, It also has a correction processing unit that generates a correction coefficient using the output signal of the sensor when a correction signal is supplied to the insulating conductor surface within the frame from the same potential unit; The correction processing unit generates correction coefficients using information from the equivalent circuit, which is based on information related to the same potential unit, the position of the sensor relative to the insulated conductor, and the measurement area inside the insulation layer of the insulated conductor. The signal processing unit generates the sensor's output signal based on the correction coefficient, which serves as a measurement signal corresponding to the partial discharge measured in the measurement area.

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