Transformer and partial discharge determination method

Abstract

To provide a transformer capable of properly measuring physical quantities for detecting partial discharge and a partial discharge determination method.SOLUTION: The transformer includes a gas-tight enclosure with insulating properties, a coil device, a cooling unit, a fan, and a sensor. The coil device is located inside the enclosure. The cooling unit is located in the enclosure and removes heat from gas. The fan is located between the coil device and the cooling unit and pumps the gas. The sensor is located in a part of the enclosure different from a part where the fan is located and measures physical quantities related to partial discharges produced by the coil device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a transformer and a method for determining partial discharge. [Background technology]

[0002] Partial discharges can occur in electric power equipment as a precursor to dielectric breakdown. Taking advantage of this characteristic, a technology is known that uses sensors to measure the physical quantities that change due to partial discharges to predict dielectric breakdown in electric power equipment. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6588781 Summary of the Invention [Problem to be solved by the invention]

[0004] A specific example of power equipment is a transformer, in which the coil is housed in a tank that seals an insulating gas to ensure insulation between the winding and the tank. It is desirable to detect partial discharges in such transformers. The problem to be solved by the present invention is to provide a transformer and a partial discharge determination method that can appropriately measure physical quantities for detecting partial discharge. [Means for solving the problem]

[0005] The transformer of the embodiment has a housing that seals an insulating gas, a coil device, a cooling unit, a fan, and a sensor. The coil device is located within the housing. The cooling unit is located in the housing and removes heat from the gas. The fan is located between the coil device and the cooling unit and pumps the gas. The sensor is located in a location on the housing different from where the fan is located and measures a physical quantity related to partial discharge generated from the coil device. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a perspective view showing the configuration of a transformer according to a first embodiment. [Figure 2] 1 is a cross-sectional view of a transformer according to a first embodiment. [Figure 3] 1 is a schematic block diagram showing the configuration of an inspection device according to a first embodiment. [Figure 4] FIG. 10 is a perspective view showing the configuration of a transformer according to a second embodiment. [Figure 5] FIG. 10 is a perspective view showing the configuration of a transformer according to a third embodiment. [Figure 6] FIG. 10 is a schematic block diagram showing the configuration of an inspection device according to a third embodiment. [Figure 7] 10 is a flowchart showing a partial discharge determination method using an inspection device according to a third embodiment. [Figure 8] FIG. 10 is a perspective view showing the configuration of a transformer according to a fourth embodiment. [Figure 9] FIG. 10 is a perspective view showing the configuration of a transformer according to a fifth embodiment. [Figure 10] FIG. 10 is a perspective view showing the configuration of a transformer according to a sixth embodiment. [Figure 11] FIG. 11 is a perspective view showing the configuration of a transformer according to a seventh embodiment. [Figure 12] FIG. 13 is a perspective view showing the configuration of a transformer according to an eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, a transformer and a partial discharge determination method according to an embodiment will be described with reference to the drawings. First Embodiment <Configuration of transformer 10> Hereinafter, the embodiments will be described in detail with reference to the drawings. Fig. 1 is a perspective view showing the configuration of a transformer 10 according to a first embodiment. Fig. 2 is a cross-sectional view of the transformer 10 according to the first embodiment. The transformer 10 according to the first embodiment is a three-phase, three-winding transformer. As shown in FIG. 1, the transformer 10 includes three coil devices 11, a coil tank 13, a heat exchanger 15, a connecting pipe 17, and a sensor 19.

[0008] The three coil devices 11 are housed in a coil tank 13. The coil tank 13 seals in the pressurized air. The pressurized air is pressurized to at least 1 atmosphere. The coil tank 13 is made of, for example, a steel plate. The heat exchanger 15 removes heat from the pressurized air filled in the coil tank 13 and releases it into the atmosphere. The connecting pipe 17 connects the coil tank 13 and the heat exchanger 15 and allows the pressurized air to flow through. The sensor 19 measures the TEV (Transient Earth Voltage) of the coil tank 13. Specifically, the sensor 19 detects the surface potential of the coil tank 13 via stray capacitance formed between the sensor 19 and the coil device 11. When a partial discharge occurs in the coil device 11, the ground voltage of the coil tank 13 changes transiently. Therefore, partial discharge can be detected by measuring the TEV with the sensor 19. In other words, the TEV is an example of a physical quantity related to partial discharge.

[0009] The compressed air is sealed by the coil tank 13, the heat exchanger 15, and the connecting pipe 17. In other words, the coil tank 13, the heat exchanger 15, and the connecting pipe 17 constitute the housing of the transformer 10.

[0010] <Configuration of coil device 11> As shown in Fig. 1, the three coil devices 11 are installed in a line inside the coil tank 13. That is, the coil tank 13 is an example of a first housing that houses the coil devices 11. The three coil devices 11 correspond to the U phase, V phase, and W phase, respectively. As shown in Fig. 2, each coil device 11 includes an iron core 111, a coil 112, and a lead wire 113.

[0011] The coil 112 has a high-voltage side winding 112a, a low-voltage side winding 112b, a gap 112c, and a covering portion 112d. High-voltage side winding 112a and low-voltage side winding 112b are wound around iron core 111. High-voltage side winding 112a functions as a primary winding to which high-voltage power is input when transformer 10 is applied to a power system. Low-voltage side winding 112b functions as a secondary winding that outputs low-voltage power when the transformer is applied to a power system. High-voltage side winding 112a is provided outside low-voltage side winding 112b. The gap 112c is formed between the high-voltage side winding 112a and the low-voltage side winding 112b. The covering 112d is formed of an insulating material with high insulation properties, such as epoxy resin, and covers the high-voltage side winding 112a and the low-voltage side winding 112b. The covering 112d is formed, for example, by immersing the high-voltage side winding 112a and the low-voltage side winding 112b in an insulating material and then curing the insulating material. The lead wires 113 include a high-voltage lead wire 113a drawn from the high-voltage winding 112a and a low-voltage lead wire 113b drawn from the low-voltage winding 112b.

[0012] <<Configuration of Coil Tank 13>> The coil tank 13 includes legs 131 , a bottom plate 132 , a side wall 133 , a cover plate 134 , a high-voltage side terminal 135 , a low-voltage side terminal 136 , an upper clamp 137 , a lower clamp 138 , and a ground electrode 139 .

[0013] The legs 131 support the coil tank 13 from below. The bottom plate 132 is provided on the legs 131. The coil device 11 is placed on the bottom plate 132. The side walls 133 are provided so as to rise upward from the edges of the bottom plate 132. The cover plate 134 is provided so as to cover the upper part of the side walls 133. The bottom plate 132, the side walls 133 and the cover plate 134 are made of steel plates.

[0014] The side wall 133 is provided with a plurality of reinforcing portions 133a for reinforcing the coil tank 13 in the circumferential direction of the coil tank 13. The reinforcing portions 133a are portions that extend horizontally and protrude outward from the side wall 133. In other words, the outer surface of the side wall 133 is formed with recesses and protrusions that extend in one direction by the reinforcing portions 133a. The reinforcing portion 133a may be, for example, a channel member (lip channel steel) with a C-shaped cross section formed by bending a steel plate, or a square steel pipe. In this case, the lip of the reinforcing portion 133a is adhered or welded to the side wall 133. Alternatively, the reinforcing portion 133a may be, for example, a convex portion formed by bending the side wall 133 into a wave shape.

[0015] The high-voltage side terminal 135 and the low-voltage side terminal 136 are provided by vertically penetrating the cover plate 134. The high-voltage side terminal 135 and the low-voltage side terminal 136 are configured, for example, by a T-shaped bushing or a direct molded bushing. The end of the high-voltage side terminal 135 inside the coil tank 13 is connected to the high-voltage side winding 112a via the high-voltage side lead wire 113a. The end of the low-voltage side terminal 136 inside the coil tank 13 is connected to the low-voltage side winding 112b via the low-voltage side lead wire 113b. The high-voltage side terminal 135 and the low-voltage side terminal 136 are output terminals electrically connected to the coil device 11.

[0016] The upper clamp 137 is provided across the three coil devices 11, and is fixed in a state in which the upper end of the iron core 111 of each coil device 11 is sandwiched therebetween. The lower clamp 138 is provided across the three coil devices 11 and is fixed in a state in which it sandwiches the lower end portion of the iron core 111 of each coil device 11. The lower clamp 138 is fixed to the bottom plate 132. The upper clamp 137 and the lower clamp 138 may be configured by, for example, a channel member (channel iron) or an angle member (angle iron) formed by bending a steel plate. The grounding electrode 139 is buried in the ground and connected via a grounding wire to the outer wall (e.g., the side wall 133) of the coil tank 13. This grounds the bottom plate 132, side wall 133, and cover plate 134 of the coil tank 13, as well as the connecting pipe 17 and heat exchanger 15 connected to the coil tank 13.

[0017] <Configuration of heat exchanger 15> The heat exchanger 15 is disposed relative to the coil tank 13 in a direction intersecting the arrangement direction of the coil device 11. For example, if the arrangement direction of the coil device 11 is defined as the left-right direction of the coil tank 13, the heat exchanger 15 is disposed behind the coil tank 13. The heat exchanger 15 has a heat exchange section including, for example, multiple tubes through which compressed air passes and fins that increase the surface area with the atmosphere. In other words, the heat exchanger 15 is an example of a second housing having a cooling section (heat exchange section). The connecting pipe 17 includes an upper connecting pipe 171 that connects the upper part of the heat exchanger 15 to the upper part of the coil tank 13 and a lower connecting pipe 172 that connects the lower part of the heat exchanger 15 to the lower part of the coil tank 13. The upper connecting pipe 171 circulates the compressed air heated by the coil device 11 to the heat exchanger 15. The lower connecting pipe 172 circulates the compressed air cooled by the heat exchanger 15 to the coil tank 13. A fan 172a is provided in the lower connecting pipe 172 to pressure-transmit pressurized air from the heat exchanger 15 to the coil tank 13. The fan 172a does not necessarily have to be an air blower, and may be a blower with a high pressure ratio, etc. In another embodiment, a fan may be provided in the upper connecting pipe 171 to pressure-transmit pressurized air from the coil tank 13 to the heat exchanger 15.

[0018] <<Placement of Sensor 19>> The sensor 19 is attached to the outer surface of the side wall 133 of the coil tank 13 . Specifically, the sensor 19 is attached to the surface of the side wall 133 opposite to the surface facing the heat exchanger 15, at a position facing the central coil device 11 of the three coil devices 11 arranged side by side. That is, the sensor 19 is provided on the front surface of the coil tank 13. The sensor 19 is also attached to a flat surface of the recess that does not have the reinforcing portion 133a, avoiding the reinforcing portion 133a of the side wall 133. In the first embodiment, the position of the side wall 133 facing the central coil device 11 of the three coil devices 11 is the point that is closest to the outer peripheral surface of the coil device 11.

[0019] That is, the sensor 19 according to the first embodiment is attached at a position different from the lower connecting pipe 172 on which the fan 172a is provided. This makes it possible to prevent noise generated by driving the fan 172a from being mixed into the measurement value of the sensor 19. Furthermore, the sensor 19 is attached while avoiding the reinforcing portion 133a, the high-voltage side terminal 135, and the low-voltage side terminal 136. This makes it possible to shorten the distance between the sensor 19 and the coil device 11. The shorter the distance between the sensor 19 and the coil device 11, the more sensitively the sensor 19 can detect the TEV emitted from the coil device 11.

[0020] <Method for detecting partial discharge in transformer 10> The presence or absence of partial discharge in the transformer 10 according to the first embodiment is determined by an inspection device 30 provided outside the transformer 10. The inspection device 30 is a computer such as a PC (Personal Computer). The inspection device 30 includes a calculation device 31 and a display 32.

[0021] FIG. 3 is a schematic block diagram showing the configuration of an inspection device 30 according to the first embodiment. The inspection device 30 includes an acquisition unit 311 , a determination unit 312 , and an output unit 313 . The acquisition unit 311 acquires the measurement value from the sensor 19 . The determination unit 312 determines whether or not a partial discharge has occurred based on the measurement value acquired by the acquisition unit 311. The output unit 313 outputs the determination result by the determination unit 312 to the display 32 .

[0022] The determination unit 312 detects partial discharge, for example, by the following method. The determination unit 312 extracts a voltage waveform having a predetermined center frequency from the measurement value acquired by the acquisition unit 311 from the sensor 19. The center frequency is determined by measuring the frequency related to the TEV of the coil device 11 through experiments or the like. The determination unit 312 observes the extracted waveform and determines whether a partial discharge has occurred. The occurrence of a partial discharge is determined, for example, based on the duration of a state in which the magnitude of the voltage waveform exceeds a predetermined threshold, the frequency at which the voltage exceeds the threshold, or the like. The threshold is determined by measuring the TEV value of the coil device 11 that is farthest from the sensor 19 through experiments or the like. Since partial discharge often manifests as intermittent discharge, the determination unit 312 determines that a partial discharge has occurred, for example, when the number of times the voltage exceeds the predetermined threshold exceeds a predetermined number.

[0023] The determination unit 312 may detect partial discharge using, for example, the following method: The acquisition unit 311 further acquires a measurement value from a sensor (not shown) connected to the ground electrode 139, and the determination unit 312 calculates the difference between the measurement value related to the ground electrode 139 and the measurement value of the sensor 19. The determination unit 312 observes the current waveform related to this difference and determines whether a pulse current is occurring. If there is strong noise superimposed on the measurement value from the sensor, the determination unit 312 can cancel out the noise by taking the difference between the measurement value at a location where partial discharge is possible and the measurement value at a location where partial discharge is not present.

[0024] That is, an inspector inspecting the transformer 10 for partial discharge attaches the sensor 19 to the side wall 133 of the coil tank 13, on the side opposite to the side facing the heat exchanger 15, at a position facing the central coil device 11 of the three coil devices 11 arranged side by side. Then, the inspector connects the sensor 19 to the inspection device 30 and causes the inspection device 30 to execute a partial discharge inspection program. As a result, the inspection device 30 determines whether or not partial discharge has occurred in the coil device 11 based on the measurement values of the sensor 19. The inspection device 30 outputs the determination result to a display 32.

[0025] Actions and Effects In this way, the sensor 19 of the transformer 10 according to the first embodiment is attached to a position on the coil tank 13 that is different from the position where the fan 172a is disposed. This allows the transformer 10 to prevent noise caused by driving the fan 172a from being superimposed on the measurement value of the sensor 19. Therefore, the inspection device 30 according to the first embodiment can accurately determine the presence or absence of partial discharge based on the measurement value of the sensor 19.

[0026] Furthermore, the sensor 19 of the transformer 10 according to the first embodiment is attached to the surface of the coil tank 13 that does not face the heat exchanger 15. Since the space between the heat exchanger 15 and the coil tank 13 is narrow, the sensor 19 is attached to the surface of the coil tank 13 that does not face the heat exchanger 15, allowing an inspector to easily access the sensor 19.

[0027] Furthermore, the sensor 19 according to the first embodiment is attached to a position facing the central coil device 11 of the three coil devices 11. This allows the TEVs of the three coil devices 11 to be detected by one sensor 19. Note that in other embodiments, when there is an even number of coil devices 11, the sensor 19 may be attached to a position corresponding to the position between the two central coil devices 11.

[0028] Second Embodiment FIG. 4 is a perspective view showing the configuration of a transformer 10 according to the second embodiment. The sensor 19 according to the first embodiment is attached to the front surface of the coil tank 13. In contrast, the sensor 19 according to the second embodiment is attached to the cover plate 134 of the coil tank 13.

[0029] <<Placement of Sensor 19>> The configuration of the transformer 10 according to the second embodiment differs from that of the first embodiment only in the mounting position of the sensor 19. The sensor 19 according to the second embodiment is attached to the cover plate 134 of the coil tank 13 at a position facing the central coil device 11 of the three coil devices 11 arranged side by side. The sensor 19 is also attached to a flat surface on which there are no terminals, avoiding the high-voltage side terminal 135 and the low-voltage side terminal 136 of the cover plate 134. This shortens the distance between the sensor 19 and the coil device 11, allowing the sensor 19 to measure the TEV of the coil device 11 with good sensitivity.

[0030] Third Embodiment FIG. 5 is a perspective view showing the configuration of a transformer 10 according to the third embodiment. The transformer 10 according to the first embodiment uses one sensor 19 to detect the TEV generated from any of the three coil devices 11. In contrast, the transformer 10 according to the second embodiment uses two sensors 19 to detect the TEV, allowing the inspection device 30 to identify in which coil device 11 a partial discharge is occurring.

[0031] <<Placement of Sensor 19>> The transformer 10 according to the third embodiment includes, instead of the sensor 19, a first sensor 19a and a second sensor 19b. The first sensor 19a is attached to the surface of the side wall 133 opposite to the surface facing the heat exchanger 15, at a position facing the coil device 11 located at the end on the first side in the arrangement direction of the three coil devices 11 arranged side by side. For example, the first sensor 19a is attached to a position facing the coil device 11 located at the leftmost side. The second sensor 19b is attached to the surface of the side wall 133 opposite to the surface facing the heat exchanger 15, at a position facing the coil device 11 located at the end on the second side in the arrangement direction of the three coil devices 11 arranged side by side. For example, the second sensor 19b is attached to a position facing the coil device 11 located at the rightmost side. The first sensor 19a and the second sensor 19b are attached to the flat surface of the recessed portion, which does not have the reinforcing portion 133a, avoiding the reinforcing portion 133a of the side wall 133.

[0032] Configuration of inspection device 30 FIG. 6 is a schematic block diagram showing the configuration of an inspection device 30 according to the third embodiment. The inspection device 30 according to the third embodiment further includes a specifying unit 314 in addition to the configuration of the first embodiment. The acquisition unit 311 is connected to the first sensor 19a and the second sensor 19b by wire or wirelessly, and acquires measurement values from each of the first sensor 19a and the second sensor 19b. The determination unit 312 determines whether or not a partial discharge occurs based on the measurement values of the first sensor 19a and the second sensor 19b. The identifying unit 314 identifies in which of the three coil devices 11 a partial discharge has occurred, based on the measurement values of the first sensor 19a and the second sensor 19b. The output unit 313 outputs the results of the determination by the determination unit 312 and the identification unit 314 to the display 32.

[0033] <Method for detecting partial discharge in transformer 10> The inspection device 30 according to the third embodiment detects partial discharge, for example, by the following method. FIG. 7 is a flowchart showing a partial discharge determination method using the inspection device 30 according to the third embodiment. The determination unit 312 of the inspection device 30 determines whether or not a partial discharge has occurred for each of the first sensor 19a and the second sensor 19b using the same method as in the first embodiment (step S1). If the determination unit 312 determines that a partial discharge has not occurred for the measurement values of both the first sensor 19a and the second sensor 19b (step S1: NO), the output unit 313 outputs a determination result indicating that a partial discharge has not occurred in the transformer 10 (step S2).

[0034] On the other hand, if the determination unit 312 determines that a partial discharge has occurred in the measurement value of at least one of the first sensor 19a and the second sensor 19b (step S1: YES), the identification unit 314 determines whether the difference between the TEV measured by the first sensor 19a and the TEV measured by the second sensor 19b is equal to or greater than a predetermined value (step S3).If the difference between the TEV measured by the first sensor 19a and the TEV measured by the second sensor 19b is less than the predetermined value (step S3: NO), the output unit 313 outputs a determination result indicating that a partial discharge has occurred in the central coil device 11 of the three coil devices 11 (step S4).

[0035] If the difference between the TEV measured by the first sensor 19a and the TEV measured by the second sensor 19b is equal to or greater than a predetermined value (step S3: NO), the identifying unit 314 determines whether the TEV measured by the first sensor 19a is greater than the TEV measured by the second sensor 19b (step S5). If the TEV measured by the first sensor 19a is greater than the TEV measured by the second sensor 19b (step S5: YES), the output unit 313 outputs a determination result indicating that a partial discharge is occurring in the coil device 11 facing the first sensor 19a, i.e., the leftmost coil device 11, of the three coil devices 11 (step S6). On the other hand, if the TEV measured by the first sensor 19a is smaller than the TEV measured by the second sensor 19b (step S5: NO), the output unit 313 outputs a determination result indicating that a partial discharge is occurring in the coil device 11 facing the second sensor 19b among the three coil devices 11, i.e., the coil device 11 located on the far right (step S7).

[0036] As described above, according to the third embodiment, the inspection device 30 can identify in which of the three coil devices 11 a partial discharge has occurred, using the first sensor 19a and the second sensor 19b.

[0037] Fourth Embodiment FIG. 8 is a perspective view showing the configuration of a transformer 10 according to the fourth embodiment. The first sensor 19a and the second sensor 19b according to the third embodiment are attached to the front surface of the coil tank 13. In contrast, the first sensor 19a and the second sensor 19b according to the fourth embodiment are attached to the side surface of the coil tank 13.

[0038] <<Placement of Sensor 19>> The configuration of the transformer 10 according to the fourth embodiment differs from that of the third embodiment only in the mounting positions of the first sensor 19a and the second sensor 19b. The first sensor 19a according to the fourth embodiment is attached to a side wall 133 on a first side in the arrangement direction of the coil devices 11, at a position facing the coil device 11 located at the end on the first side in the arrangement direction. For example, the first sensor 19a is attached to a left side surface of the coil tank 13, at a position facing the coil device 11 located on the leftmost side. The second sensor 19b according to the fourth embodiment is attached to a side wall 133 on a second side in the arrangement direction of the coil devices 11, at a position facing the coil device 11 located at the end on the second side in the arrangement direction. For example, the first sensor 19a is attached to a right side surface of the coil tank 13, at a position facing the coil device 11 located at the rightmost side. The first sensor 19a and the second sensor 19b are attached to the flat surface of the recessed portion, which does not have the reinforcing portion 133a, avoiding the reinforcing portion 133a of the side wall 133.

[0039] Fifth Embodiment FIG. 9 is a perspective view showing the configuration of a transformer 10 according to the fifth embodiment. The first sensor 19a and the second sensor 19b according to the third embodiment are attached to the front surface of the coil tank 13. In contrast, the first sensor 19a and the second sensor 19b according to the fifth embodiment are attached to the back surface of the coil tank 13.

[0040] <<Placement of Sensor 19>> The configuration of the transformer 10 according to the fifth embodiment differs from that of the third embodiment only in the mounting positions of the first sensor 19a and the second sensor 19b. The first sensor 19a according to the fifth embodiment is attached to a surface of the side wall 133 facing the heat exchanger 15, at a position facing the coil device 11 located at the end on the first side in the arrangement direction of the three coil devices 11 arranged side by side. For example, the first sensor 19a is attached to a position facing the coil device 11 located on the leftmost side. The second sensor 19b according to the fifth embodiment is attached to a surface of the side wall 133 facing the heat exchanger 15, at a position facing the coil device 11 located at the end on the second side in the arrangement direction of the three coil devices 11 arranged side by side. For example, the second sensor 19b is attached to a position facing the coil device 11 located at the rightmost side. The first sensor 19a and the second sensor 19b are attached to the flat surface of the recessed portion where the reinforcing portion 133a is not present, avoiding the reinforcing portion 133a of the side wall 133. The first sensor 19a and the second sensor 19b are attached to a position different from the position where the lower connecting pipe 172 having the fan 172a is disposed. This makes it possible to prevent noise generated by the operation of the fan 172a from being mixed into the measurement value of the sensor 19.

[0041] Sixth Embodiment FIG. 10 is a perspective view showing the configuration of a transformer 10 according to the sixth embodiment. The first sensor 19a and the second sensor 19b according to the third embodiment are attached to the front surface of the coil tank 13. In contrast, the first sensor 19a and the second sensor 19b according to the sixth embodiment are attached to the bottom surface of the coil tank 13.

[0042] <<Placement of Sensor 19>> The configuration of the transformer 10 according to the sixth embodiment differs from that of the third embodiment only in the mounting positions of the first sensor 19a and the second sensor 19b. The first sensor 19a according to the sixth embodiment is attached to the side wall 133 on the outside of a position facing the coil device 11 located at the end on the first side in the arrangement direction. For example, the first sensor 19a is attached further to the left of a position facing the coil device 11 located at the leftmost side. The second sensor 19b according to the sixth embodiment is attached to the side wall 133 on the outer side of a position facing the coil device 11 located at the end on the second side in the arrangement direction. For example, the second sensor 19b is attached to the right of a position facing the rightmost coil device 11.

[0043] The first sensor 19a and the second sensor 19b of the transformer 10 according to the sixth embodiment are attached to the bottom surface of the coil tank 13. Because the height of the bottom surface of the coil tank 13 is low, the first sensor 19a and the second sensor 19b are attached to the surface of the coil tank 13 that does not face the heat exchanger 15, allowing an inspector to easily access the first sensor 19a and the second sensor 19b.

[0044] Seventh Embodiment FIG. 11 is a perspective view showing the configuration of a transformer 10 according to the seventh embodiment. The heat exchanger 15 according to the first embodiment is provided behind the coil tank 13. In contrast, the heat exchanger 15 according to the seventh embodiment is provided above the coil tank 13. That is, in the seventh embodiment, the heat exchanger 15 and the coil device 11 are provided at positions at different heights.

[0045] <<Placement of Sensor 19>> The sensor 19 is attached to the surface of the side wall 133 opposite to the surface facing the heat exchanger 15, at a position facing the central coil device 11 of the three coil devices 11 arranged side by side. The sensor 19 is also attached to the flat surface of the recess where there is no reinforcing portion 133a, avoiding the reinforcing portion 133a of the side wall 133.

[0046] Eighth Embodiment FIG. 12 is a perspective view showing the configuration of a transformer 10 according to the eighth embodiment. The inspection device 30 according to the first embodiment is provided separately from the transformer 10. In contrast, in the transformer 10 according to the eighth embodiment, the control device 21 provided in the transformer 10 functions as the inspection device.

[0047] 12, the control device 21 is provided on the cover plate 134 of the transformer 10. The control device 21 periodically detects partial discharges based on the measurement values of the sensor 19 while controlling the behavior of the transformer 10.

[0048] Other Embodiments Although several embodiments have been described in detail above with reference to the drawings, the specific configurations are not limited to those described above, and various design modifications are possible. That is, in other embodiments, the order of the above-described processes may be changed as appropriate. Furthermore, some processes may be executed in parallel. The inspection device 30 according to the above-described embodiment may be configured by a single computer, or the configuration of the inspection device 30 may be divided into multiple computers that cooperate with each other to function as the inspection device 30. In this case, some of the computers that configure the inspection device 30 may be mounted on the transformer 10, and other computers may be provided outside the transformer 10.

[0049] The sensor 19 according to the embodiment described above measures the TEV of the coil device 11, but is not limited to this. For example, the sensor 19 according to other embodiments may be any sensor that can measure current, electromagnetic waves, sound waves, or vibrations resulting from partial discharge in the coil device 11.

[0050] The transformer 10 according to the embodiment described above includes three coil devices 11, but is not limited to this. For example, the transformer 10 according to other embodiments may include two or less coil devices 11, or may include four or more coil devices 11.

[0051] In the above-described embodiment, the cooling unit includes the heat exchanger 15 using a radiator, but is not limited to this. For example, the cooling unit according to another embodiment may cool the pressurized air using a heat pump.

[0052] In the above-described embodiment, the transformer 10 seals compressed air, but this is not limiting. For example, in other embodiments, the transformer 10 may seal other insulating gases, such as SF6 gas. Also, in other embodiments, the coil 112 does not necessarily have to be molded.

[0053] In the above-described embodiment, the housing of the transformer 10 is composed of the coil tank 13, the heat exchanger 15, and the connecting pipe 17, but this is not limited to this. For example, the transformer 10 according to another embodiment may have a housing in which the coil tank 13 and the heat exchanger 15 are integrated.

[0054] <Computer Configuration> The inspection device 30 and the control device 21 include a processor, a memory, an auxiliary storage device, etc., which are connected by a bus, and by executing a partial discharge detection program, function as a device including an acquisition unit 311, a determination unit 312, and an output unit 313. Examples of the processor include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor. The partial discharge detection program may be recorded on a computer-readable recording medium. Examples of the computer-readable recording medium include a storage device such as a magnetic disk, a magneto-optical disk, an optical disk, or a semiconductor memory. The partial discharge detection program may be transmitted via a telecommunications line. All or part of the functions of the inspection device 30 or the control device 21 may be realized using a custom LSI (Large Scale Integrated Circuit) such as an ASIC (Application Specific Integrated Circuit) or a PLD (Programmable Logic Device). Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). Such integrated circuits are also included in the scope of a processor.

[0055] According to at least one of the embodiments described above, the transformer 10 has a sensor for measuring a physical quantity related to partial discharge at a location on the housing different from the location where the fan 172a is located, thereby making it possible to appropriately measure the physical quantity for detecting partial discharge. Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0056] 10...transformer, 11...coil device, 13...coil tank, 15...heat exchanger, 17...connecting pipe, 171...upper connecting pipe, 172...lower connecting pipe, 172a...fan, 19...sensor, 30...inspection device, 311...acquisition unit, 312...determination unit, 313...output unit, 314...identification unit

Claims

1. a housing that seals an insulating fluid; a coil device located within the housing; a cooling unit located in the housing and configured to remove heat from the fluid; a pumping device that pumps the fluid and causes the fluid to circulate between the coil device and the cooling unit; a sensor attached to a location of the housing different from a location where the pumping device is located, for measuring a transient ground voltage of the housing; A transformer comprising:

2. the housing includes a first housing that houses the coil device, a second housing that has the cooling unit, and a connecting pipe that connects the first housing and the second housing, the pumping device is located within the connecting pipe; The sensor is attached to the first housing.

10. The transformer of claim 1.

3. The sensor is attached to a surface of the first housing that does not face the second housing.

3. The transformer according to claim 2.

4. The sensor is attached to a surface of the first housing facing the second housing at a location different from a location where the connecting pipe is disposed.

3. The transformer according to claim 2.

5. the cooling unit and the coil device are located at different heights, The sensor is attached to a surface of the housing facing the coil device. A transformer according to any one of claims 1 to 4.

6. a plurality of coil devices including the coil device arranged in one direction within the housing; The sensor is attached to a surface of the housing facing a central portion of the plurality of coil devices. A transformer according to any one of claims 1 to 5.

7. a plurality of coil devices including the coil device arranged in one direction within the housing; the sensor includes a first sensor and a second sensor for measuring the transient ground voltage; the first sensor is attached to a surface of the housing that faces one of the plurality of coil devices that is provided at a first end in the one direction, The second sensor is attached to a surface of the housing that faces one of the plurality of coil devices that is provided at the second end in the one direction. A transformer according to any one of claims 1 to 5.

8. the first sensor is attached to a surface of the housing on the first end side, The second sensor is attached to a surface of the housing on the second end side.

8. The transformer according to claim 7.

9. The sensor is attached to a portion of the surface of the housing that is closest to the outer circumferential surface of the coil device. A transformer according to any one of claims 1 to 8.

10. The outer surface of the housing has a recess and a protrusion extending in one direction, The sensor is attached to the recess.

10. A transformer according to any one of claims 1 to 9.

11. a take-out terminal electrically connected to the coil device is located on an outer surface of the housing; The sensor is attached at a location different from the location at which the lead terminal is disposed. A transformer according to any one of claims 1 to 10.

12. The sensor is attached to the bottom surface of the housing at a location that does not face the coil device.

3. The transformer according to claim 1 or 2.

13. the housing seals the fluid at 1 atmosphere or more, The surface of the coil device is covered with an insulating material. A transformer according to any one of claims 1 to 12.

14. The sensor is attached to the outer surface of the housing. A transformer according to any one of claims 1 to 13.

15. A determination unit is provided to determine whether or not partial discharge occurs in the coil device based on the measurement value of the sensor.

15. A transformer according to any one of claims 1 to 14.

16. an identifying unit that identifies a coil device that is generating a partial discharge among the plurality of coil devices based on the measurement value of the first sensor and the measurement value of the second sensor; 9. The transformer according to claim 7 or claim 8.

17. a transformer including a housing that seals an insulating fluid, a coil device located within the housing, a cooling unit located within the housing that removes heat from the fluid, and a pumping device that pumps the fluid and circulates the fluid between the coil device and the cooling unit; and a step of attaching a sensor to the housing at a location different from a location where the pumping device is located; the sensor measuring the transient ground voltage of the housing; determining whether or not a partial discharge occurs in the coil device based on the measurement value of the sensor; A partial discharge determination method comprising:

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