Insulation Resistance Monitoring Device

Abstract

To accurately measure the insulation resistance of an object to be measured in consideration of variations in insulation resistance due to a surrounding environment of the object to be measured.SOLUTION: An insulation resistance measuring instrument measures and outputs insulation resistance of an object to be measured. A movement information receiving unit 44 receives information indicating whether the object to be measured is in moving or stopped. A humidity information receiving unit 45 receives humidity in the vicinity of the object to be measured. A controller 46 controls the insulation resistance measuring instrument so as to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped and the humidity in the vicinity of the object to be measured is equal to or more than a first threshold value Th1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an insulation resistance monitoring device. [Background technology]

[0002] The Electricity Business Act requires that electrical equipment such as high-voltage substations and switchboards be inspected approximately once a year. In addition, businesses also inspect motors and other electrical equipment connected to switchboards voluntarily, according to their own management standards, approximately once a week to once a month.

[0003] However, the objects (objects to be measured) of the self-inspection include a wide variety of electrical facilities and electrical equipment, and the reality is that the number is so large that it is practically impossible to handle them all. Therefore, insulation resistance monitoring devices have been developed to automate the self-inspection.

[0004] For example, Patent Document 1 discloses an insulation resistance monitoring device that includes a switch that opens and closes a connection path between a power line or earth line of an object to be measured and a voltage generating section of the insulation resistance monitoring device. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-148736 A Summary of the Invention [Problem to be solved by the invention]

[0006] The insulation resistance of the object to be measured may vary depending on the state of the environment surrounding the object to be measured. For this reason, a temporarily increased insulation resistance may be obtained, and as a result, deterioration in the insulation performance of the object to be measured that should be checked may be overlooked. In addition, when the insulation resistance varies, it is not possible to determine whether the cause of the variation is the influence of the surrounding environment or the deterioration of the insulation performance. Therefore, it is required to measure the insulation resistance of the object to be measured with high accuracy, taking into account the variation in insulation resistance caused by the environment surrounding the object to be measured.

[0007] An object of the present disclosure is to provide an insulation resistance monitoring device that can measure the insulation resistance of an object to be measured with high accuracy, taking into account fluctuations in insulation resistance caused by the environment surrounding the object to be measured. [Means for solving the problem]

[0008] An insulation resistance monitoring device according to one aspect of the present invention comprises: an insulation resistance measuring instrument for measuring and outputting the insulation resistance of an object to be measured; an operation information receiving unit for receiving information indicating that the object to be measured is in operation or stopped; a humidity information receiving unit that receives the humidity in the vicinity of the object to be measured; and a controller that controls the insulation resistance measuring instrument to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped and the humidity in the vicinity of the object to be measured is equal to or higher than a first threshold value.

[0009] This makes it possible to measure the insulation resistance of the object to be measured with high accuracy, taking into account fluctuations in insulation resistance caused by the environment surrounding the object to be measured.

[0010] According to an insulation resistance monitoring device according to one aspect of the present invention, The insulation resistance monitoring device further includes a timer that measures an elapsed time after the object to be measured has stopped, The controller controls the insulation resistance measuring instrument to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped, a predetermined first time period has elapsed since the object to be measured was stopped, and the humidity in the vicinity of the object to be measured is equal to or higher than the first threshold value.

[0011] This makes it possible to measure the insulation resistance of the object to be measured with high accuracy, taking into account the humidity fluctuations caused by the operation of the object to be measured.

[0012] According to an insulation resistance monitoring device according to one aspect of the present invention, The insulation resistance monitoring device further includes a storage device that stores the insulation resistance of the object to be measured measured by the insulation resistance measuring instrument, The controller: controlling the insulation resistance tester to measure the insulation resistance of the device under test for a second predetermined time period; storing in the storage device the humidity in the vicinity of the object to be measured, which is received when the insulation resistance of the object to be measured is measured together with the insulation resistance of the object to be measured by the insulation resistance measuring instrument; selecting a humidity corresponding to a minimum insulation resistance among the plurality of insulation resistances stored in the storage device as the first threshold value; The first threshold is set.

[0013] This makes it possible to automatically set an appropriate humidity threshold value according to the environment surrounding the object to be measured, thereby enabling the insulation resistance of the object to be measured with high accuracy.

[0014] According to an insulation resistance monitoring device according to one aspect of the present invention, The controller sets the first threshold value when a period during which the humidity in the vicinity of the object to be measured is less than the first threshold value exceeds a predetermined third time period.

[0015] This makes it possible to prevent a situation in which the insulation resistance of the object to be measured cannot be measured for a long period of time by resetting the humidity threshold value even if the environment around the object to be measured changes.

[0016] According to an insulation resistance monitoring device according to one aspect of the present invention, The insulation resistance monitoring device further includes a temperature information receiving unit that receives a temperature in the vicinity of the object to be measured, The controller controls the insulation resistance measuring instrument to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped, the humidity near the object to be measured is equal to or higher than the first threshold value, and the temperature near the object to be measured is equal to or higher than the second threshold value.

[0017] This makes it possible to measure the insulation resistance of the object to be measured with high accuracy, taking into account fluctuations in insulation resistance caused by the environment surrounding the object to be measured.

[0018] According to an insulation resistance monitoring device according to one aspect of the present invention, The insulation resistance monitoring device further includes a timer that measures an elapsed time after the object to be measured has stopped, The controller controls the insulation resistance measuring instrument to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped, a predetermined first time period has elapsed since the object to be measured was stopped, the humidity near the object to be measured is equal to or greater than the first threshold value, and the temperature near the object to be measured is equal to or greater than the second threshold value.

[0019] This makes it possible to measure the insulation resistance of the object to be measured with high accuracy, taking into account the humidity fluctuations caused by the operation of the object to be measured.

[0020] According to an insulation resistance monitoring device according to one aspect of the present invention, The insulation resistance monitoring device further includes a storage device that stores the insulation resistance of the object to be measured measured by the insulation resistance measuring instrument, The controller: controlling the insulation resistance tester to measure the insulation resistance of the device under test for a second predetermined time period; storing in the storage device the insulation resistance of the object measured by the insulation resistance measuring instrument and a temperature in the vicinity of the object received when the insulation resistance of the object was measured; selecting a temperature corresponding to a minimum insulation resistance among the plurality of insulation resistances stored in the storage device as the second threshold value; The second threshold is set.

[0021] This makes it possible to automatically set an appropriate temperature threshold value according to the environment surrounding the object to be measured, thereby enabling the insulation resistance of the object to be measured with high accuracy.

[0022] According to an insulation resistance monitoring device according to one aspect of the present invention, The controller sets the second threshold when a period during which the temperature in the vicinity of the object to be measured is below the second threshold exceeds a predetermined third time period.

[0023] This makes it possible to prevent a situation in which the insulation resistance of the object to be measured cannot be measured for a long period of time by resetting the temperature threshold value even if the environment around the object to be measured changes. Effect of the Invention

[0024] According to an insulation resistance monitoring device according to one aspect of the present invention, it is possible to measure the insulation resistance of an object to be measured with high accuracy, taking into account fluctuations in insulation resistance caused by the environment surrounding the object to be measured. [Brief description of the drawings]

[0025] [Figure 1] 1 is a block diagram showing an example of the configuration of a motor system including an insulation resistance monitoring device 40 according to a first embodiment. [Diagram 2] 2 is a graph showing an example of the characteristics of the insulation resistance value Ro of the three-phase motor device 30 of FIG. 1 with respect to humidity and temperature. [Diagram 3] 2 is an exemplary timing chart showing measurement of an insulation resistance value Ro of the three-phase motor device 30 by the insulation resistance monitoring device 40 of FIG. 1. [Figure 4] 2 is a flowchart showing an example of an insulation resistance monitoring process executed by a controller 46 of FIG. 1. [Diagram 5] 11 is a block diagram showing an example of the configuration of a motor system including an insulation resistance monitoring device 40A according to a second embodiment. FIG. [Figure 6] 6 is an exemplary timing chart showing measurement of an insulation resistance value Ro of a three-phase motor device 30A by the insulation resistance monitoring device 40A of FIG. 5. [Figure 7] 6 is a flowchart showing an example of an insulation resistance monitoring process executed by a controller 46A of FIG. 5. [Figure 8] FIG. 11 is a block diagram showing an example of the configuration of a motor system including an insulation resistance monitoring device 40B according to a third embodiment. [Figure 9] 9 is an exemplary timing chart showing measurement of an insulation resistance value Ro of the three-phase motor device 30 by the insulation resistance monitoring device 40B of FIG. 8. [Figure 10] 9 is a flowchart showing an example of an insulation resistance monitoring process executed by a controller 46B of FIG. 8. [Figure 11] FIG. 11 is a block diagram showing an example of the configuration of a motor system including an insulation resistance monitoring device 40C according to a fourth embodiment. [Figure 12] 12 is an exemplary timing chart showing measurement of an insulation resistance value Ro of a three-phase motor device 30A by the insulation resistance monitoring device 40C of FIG. 11. [Figure 13] 12 is a table showing insulation resistance values ​​Ro of a three-phase motor device 30A measured under various humidity and temperature conditions by the insulation resistance monitoring device 40C of FIG. 11. [Figure 14] 12 is a flowchart showing an example of an insulation resistance monitoring process executed by a controller 46C of FIG. 11. [Figure 15]15 is a flowchart showing a subroutine of the threshold setting process in step S32 of FIG. 14. [Figure 16] 12 is a flowchart showing a modified example of the insulation resistance monitoring process executed by the controller 46C of FIG. 11. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment according to one aspect of the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals denote similar components.

[0027] [Example of application] Fig. 1 is a block diagram showing an example of the configuration of a motor system including an insulation resistance monitoring device 40 according to a first embodiment. The motor system in Fig. 1 includes, for example, a three-phase AC power supply device 10, a circuit breaker 20, a three-phase motor device 30, and an insulation resistance monitoring device 40. The three-phase AC power supply device 10 supplies three-phase AC power to the three-phase motor device 30 via the circuit breaker 20. The example in Fig. 1 shows a case where the insulation resistance monitoring device 40 measures an insulation resistance value Ro of the three-phase motor device 30 as a measured object.

[0028] The insulation resistance monitoring device 40 includes a current measuring device 41, an insulation resistance calculator 42, a display device 43, an operation information receiving unit 44, a humidity information receiving unit 45, a controller 46, a voltage source E1, and a switch SW.

[0029] The voltage source E1 supplies a predetermined voltage to be applied between two mutually insulated nodes of the three-phase motor device 30. The switch SW opens and closes a circuit between the three-phase motor device 30 and the voltage source E1. The current measuring device 41 measures a leakage current that flows between the two mutually insulated nodes of the three-phase motor device 30 due to the voltage supplied by the voltage source E1. The insulation resistance calculator 42 calculates an insulation resistance value Ro of the three-phase motor device 30 based on the leakage current measured by the current measuring device 41. The display device 43 outputs the insulation resistance value Ro calculated by the insulation resistance calculator 42.

[0030] The current measuring device 41, the insulation resistance calculator 42, the display device 43, the voltage source E1, and the switch SW are an example of an insulation resistance measuring device that measures and outputs the insulation resistance value Ro of the three-phase motor device 30.

[0031] The operation information receiving unit 44 receives and acquires information indicating that the three-phase motor device 30 is operating or stopped. The humidity information receiving unit 45 receives and acquires humidity in the vicinity of the three-phase motor device 30. When the three-phase motor device 30 is stopped and the humidity in the vicinity of the three-phase motor device 30 is equal to or higher than a predetermined threshold value Th1, the controller 46 controls the insulation resistance calculator 42 to measure the insulation resistance value Ro of the three-phase motor device 30 and output it via the display device 43.

[0032] FIG. 2 is a graph showing an example of the characteristics of the insulation resistance value Ro of the three-phase motor device 30 of FIG. 1 with respect to humidity and temperature. As described above, the insulation resistance of the object to be measured by the insulation resistance monitoring device 40 (e.g., the three-phase motor device 30) may vary depending on the state of the environment around the object to be measured. For example, as shown in FIG. 2, the insulation resistance of the three-phase motor device 30 may vary depending on the humidity and temperature (air temperature) in the vicinity of the three-phase motor device 30. In the example of FIG. 2, the higher the humidity, the lower the insulation resistance, and the higher the temperature, the lower the insulation resistance. Therefore, if the insulation resistance of the three-phase motor device 30 is measured when the humidity and temperature temporarily decrease, a temporarily increased insulation resistance is obtained, and as a result, there is a risk that deterioration of the insulation performance of the three-phase motor device 30 that should be inspected will be overlooked. In addition, when the insulation resistance varies, it is not possible to determine whether the cause of the variation is due to the influence of the surrounding environment (i.e., humidity or temperature) or deterioration of the insulation performance. Therefore, it is required to measure the insulation resistance of the object to be measured with high accuracy, taking into account the variation of the insulation resistance caused by the environment around the object to be measured.

[0033] According to the insulation resistance monitoring device 40 of the first embodiment, when the humidity in the vicinity of the three-phase motor device 30 is equal to or higher than the threshold value Th1, the insulation resistance value Ro of the three-phase motor device 30 is measured and output, while when the humidity is lower than the threshold value Th1, the insulation resistance value Ro is not measured and output (at least, such insulation resistance value Ro is not output). Therefore, when a high insulation resistance value Ro is measured and output, it can be determined that the insulation performance of the three-phase motor device 30 has not deteriorated. Also, when a low insulation resistance value Ro is measured and output, it can be determined that the insulation performance of the three-phase motor device 30 has deteriorated. In this way, according to the insulation resistance monitoring device 40 of the first embodiment, the insulation resistance value Ro of the three-phase motor device 30 can be measured with high accuracy and presented to the user, taking into account the fluctuation of the insulation resistance value Ro caused by the environment around the three-phase motor device 30.

[0034] In an environment of room temperature, for example 20 to 30° C., where an object to be measured is likely to be placed, humidity is considered to be more dominant than temperature in fluctuations in insulation resistance value Ro. Therefore, in the first embodiment, the insulation resistance value Ro of the three-phase motor device 30 is measured and output, taking into account the humidity in the vicinity of the three-phase motor device 30.

[0035] [First embodiment] The insulation resistance monitoring device according to the first embodiment will be further described below.

[0036] [Configuration example of the first embodiment] The three-phase AC power supply device 10 includes three single-phase AC power supplies 11-13. The single-phase AC power supplies 11-13 generate single-phase AC voltages having phases that differ from each other by 120 degrees each. In the example of Fig. 1, the single-phase AC power supplies 11-13 are connected to each other in a Δ connection. Nodes N1-N3 that connect the single-phase AC power supplies 11-13 to each other are connected to a circuit breaker 20 and a three-phase motor device 30 via U-phase, V-phase, and W-phase power supply lines.

[0037] The three-phase AC power supply device 10 may include a distribution board, a high-voltage substation equipment, etc. In this case, the high-voltage substation equipment steps down a voltage of, for example, 6600 V supplied from an electric power company to a voltage of, for example, about 200 V to 480 V. The distribution board distributes the stepped-down voltage to the three-phase motor device 30 and other load devices.

[0038] The circuit breaker 20 includes switches 21-23 inserted in the U-phase, V-phase, and W-phase power lines, respectively. The circuit breaker 20 further includes an operation sensor 24 that detects the on / off of the switches 21-23 and thereby detects whether the three-phase motor device 30 is operating or stopped. The operation sensor 24 may be, for example, another switch that is turned on / off in conjunction with the switches 21-23.

[0039] The three-phase motor device 30 includes windings 31-33 and a housing 34. In the example of Fig. 1, the windings 31-33 are connected to each other in a delta connection. Nodes N4-N6 connecting the windings 31-33 to each other are connected to the U-phase, V-phase, and W-phase power supply lines. The housing 34 is another node electrically insulated from the windings 31-33. The housing 34 may be grounded.

[0040] A leakage current may flow between the windings 31-33 and the housing 34. The example in Fig. 1 shows a case where a ground insulation resistor 35 through which a leakage current of a resistance flows is generated between the node N4 and the housing 34. The ground insulation resistor 35 has an insulation resistance value Ro.

[0041] The three-phase motor device 30 further includes a humidity sensor 36 that detects humidity in the vicinity of the three-phase motor device 30. Here, the "vicinity" of the three-phase motor device 30 includes a position where humidity that affects the insulation resistance value Ro of the three-phase motor device 30 can be detected, for example, the inside of the housing 34.

[0042] The voltage source E1 supplies a predetermined voltage to be applied between two mutually insulated nodes of the three-phase motor device 30, in the example of Fig. 1, between the node N4 and the housing 34. The voltage source E1 supplies a DC voltage of, for example, 50V.

[0043] The switch SW opens and closes a circuit between the three-phase motor device 30 and the voltage source E1. In the example of FIG. 1, the switch SW is inserted between the node N4 and the voltage source E1, but may be inserted at another position. The switch SW may be, for example, a mechanical switch operated by a user, or a reed relay that operates in response to an external control signal. The resistance value of the switch SW in the open state is set according to the desired insulation resistance of the object to be measured. For example, when the insulation resistance value Ro of the three-phase motor device 30 is about 100 MΩ, the switch SW has a resistance value of 100 MΩ or more, preferably 1000 MΩ or more, in the open state.

[0044] When the switch SW is turned on, the current measuring device 41 measures a leakage current that flows between two mutually insulated nodes of the three-phase motor device 30 due to the voltage supplied by the voltage source E1, in the example of Fig. 1, the leakage current that flows through the ground insulation resistor 35 between the node N4 and the housing 34. The current measuring device 41 includes an operational amplifier and the like, and is configured to measure a current having a magnitude on the order of several µA to several tens of µA, for example.

[0045] The insulation resistance calculator 42 calculates the insulation resistance value Ro of the three-phase motor device 30 based on the voltage supplied by the voltage source E1 and the leakage current measured by the current measuring device 41. The insulation resistance calculator 42 may determine whether the insulation resistance value Ro satisfies the requirements stipulated by laws and regulations. The insulation resistance calculator 42 outputs the calculation results and the determination results to the display device 43.

[0046] The display device 43 displays the insulation resistance value Ro of the three-phase motor device 30. In addition to or instead of the insulation resistance value Ro, the display device 43 may display whether or not the insulation resistance value Ro satisfies the requirements stipulated by law.

[0047] The operation information receiving unit 44 receives information indicating whether the three-phase motor device 30 is operating or stopped from the operation sensor 24, and notifies the controller 46 of the information.

[0048] The humidity information receiving unit 45 receives the humidity in the vicinity of the three-phase motor device 30 from the humidity sensor 36 and notifies the controller 46 of the humidity.

[0049] When the three-phase motor device 30 is stopped and the humidity in the vicinity of the three-phase motor device 30 is equal to or higher than a predetermined threshold value Th1, the controller 46 controls the insulation resistance calculator 42 to calculate the insulation resistance value Ro of the three-phase motor device 30 and output it via the display device 43. The threshold value Th1 is set to, for example, 50% so that the insulation resistance value Ro of the three-phase motor device 30 is sufficiently small.

[0050] For example, when measuring the insulation resistance value Ro of the three-phase motor device 30 using an insulation resistance meter other than the insulation resistance monitoring device 40 for a statutory inspection, the user turns off the circuit breaker 20 and the switch SW, and connects the probes of the insulation resistance meter to two mutually insulated nodes (e.g., node N4 and the housing 34) of the three-phase motor device 30. This allows the insulation resistance value Ro of the three-phase motor device 30 to be measured using the insulation resistance meter without removing the insulation resistance monitoring device 40 from the three-phase motor device 30.

[0051] [Operation example of the first embodiment] 3 is an exemplary timing chart showing the measurement of the insulation resistance value Ro of the three-phase motor device 30 by the insulation resistance monitoring device 40 of FIG. 1. In the example of FIG. 3, the three-phase motor device 30 is in operation during time periods t1-t2 and t3-t4, and is stopped during other time periods. When the three-phase motor device 30 is stopped, the humidity in the vicinity of the three-phase motor device 30 increases beyond the threshold value Th1 at times t11 and t12. As described above, the insulation resistance monitoring device 40 measures and outputs the insulation resistance value Ro of the three-phase motor device 30 when the three-phase motor device 30 is stopped and the humidity in the vicinity of the three-phase motor device 30 is equal to or greater than the threshold value Th1.

[0052] FIG. 4 is a flowchart showing an example of an insulation resistance monitoring process executed by the controller 46 of FIG.

[0053] In step S1, the controller 46 determines whether or not the three-phase motor device 30 is stopped based on information from the operation information receiving unit 44. If YES, the controller 46 proceeds to step S2, and if NO, the controller 46 repeats step S1.

[0054] In step S2, the controller 46 acquires the humidity H in the vicinity of the three-phase motor device 30 from the humidity information receiving unit 45. In step S3, the controller 46 determines whether the humidity H in the vicinity of the three-phase motor device 30 is equal to or greater than the threshold value Th1, and if YES, the controller 46 proceeds to step S4, and if NO, the controller 46 returns to step S1.

[0055] In step S4, the controller 46 controls the insulation resistance calculator 42 to measure the insulation resistance value Ro and output it via the display device 43.

[0056] According to the insulation resistance monitoring process of FIG. 4, the insulation resistance value Ro of the three-phase motor device 30 can be measured with high accuracy and presented to the user, taking into account fluctuations in the insulation resistance value Ro caused by fluctuations in humidity in the vicinity of the three-phase motor device 30.

[0057] [Advantages of the First Embodiment] According to the insulation resistance monitoring device 40 of the first embodiment, the insulation resistance value Ro of the three-phase motor device 30 can be measured with high accuracy and presented to the user, taking into account fluctuations in the insulation resistance value Ro caused by fluctuations in humidity in the vicinity of the three-phase motor device 30.

[0058] [Second embodiment] Next, an insulation resistance monitoring device according to a second embodiment will be described.

[0059] [Configuration example of the second embodiment] Fig. 5 is a block diagram showing an example of the configuration of a motor system including an insulation resistance monitoring device 40A according to a second embodiment. The motor system in Fig. 5 includes a three-phase motor device 30A and an insulation resistance monitoring device 40A instead of the three-phase motor device 30 and the insulation resistance monitoring device 40 in Fig. 1.

[0060] 1, the three-phase motor device 30A includes a temperature sensor 37 for detecting the temperature in the vicinity of the three-phase motor device 30A. Here, the "vicinity" of the three-phase motor device 30A includes a position where the temperature that affects the insulation resistance value Ro of the three-phase motor device 30A can be detected, for example, the inside of the housing 34.

[0061] The insulation resistance monitoring device 40A includes a controller 46A instead of the controller 46 of the insulation resistance monitoring device 40 of FIG.

[0062] The temperature information receiving unit 47 receives the temperature in the vicinity of the three-phase motor device 30A from the temperature sensor 37 and notifies the controller 46A.

[0063] When the three-phase motor device 30A is stopped, the humidity in the vicinity of the three-phase motor device 30A is equal to or higher than a first threshold value Th1, and the temperature in the vicinity of the three-phase motor device 30A is equal to or higher than a predetermined second threshold value Th2, the controller 46A controls the insulation resistance calculator 42 to calculate the insulation resistance value Ro of the three-phase motor device 30A and output the calculated value via the display device 43. The threshold value Th2 is set to, for example, 25° C. so that the insulation resistance value Ro of the three-phase motor device 30A is sufficiently small.

[0064] [Operation example of the second embodiment] Fig. 6 is an exemplary timing chart showing the measurement of the insulation resistance value Ro of the three-phase motor device 30A by the insulation resistance monitoring device 40A of Fig. 5. In the example of Fig. 3, when the three-phase motor device 30A is stopped, the humidity and temperature near the three-phase motor device 30A are higher than the threshold values ​​Th1 and Th2, respectively, at times t21 and t22. As described above, when the three-phase motor device 30A is stopped, the humidity near the three-phase motor device 30A is equal to or higher than the threshold value Th1, and the temperature near the three-phase motor device 30A is equal to or higher than the threshold value Th2, the insulation resistance monitoring device 40A measures and outputs the insulation resistance value Ro of the three-phase motor device 30A.

[0065] FIG. 7 is a flowchart showing an example of an insulation resistance monitoring process executed by the controller 46A of FIG.

[0066] Steps S11 to S13 are similar to steps S1 to S3 in FIG.

[0067] In step S14, the controller 46A The temperature information receiving unit 47 receives the temperature information from the three-phase motor device. 30A In step S15, the controller 46A is a three-phase motor device 30A If the result is YES, the process proceeds to step S16, and if the result is NO, the process returns to step S11.

[0068] In step S16, the controller 46A 4, controls the insulation resistance calculator 42 to measure the insulation resistance value Ro and output it via the display device 43.

[0069] According to the insulation resistance monitoring process of FIG. 4, the insulation resistance value Ro of the three-phase motor device 30A can be measured with high accuracy and presented to the user, taking into account fluctuations in the insulation resistance value Ro caused by fluctuations in humidity and temperature in the vicinity of the three-phase motor device 30A.

[0070] [Effects of the second embodiment] According to the insulation resistance monitoring device 40A of the second embodiment, the insulation resistance value Ro of the three-phase motor device 30A can be measured with high accuracy and presented to the user, taking into account the fluctuation of the insulation resistance value Ro caused by the fluctuation of the humidity and temperature in the vicinity of the three-phase motor device 30A. By taking into account both the humidity and the temperature, the insulation resistance value Ro of the three-phase motor device 30A can be measured with higher accuracy than in the first embodiment and presented to the user.

[0071] [Third embodiment] Next, an insulation resistance monitoring device according to a third embodiment will be described.

[0072] [Configuration example of the third embodiment] 8 is a block diagram showing an example of the configuration of a motor system including an insulation resistance monitoring device 40B according to a third embodiment. The motor system of FIG. 8 includes an insulation resistance monitoring device 40B instead of the insulation resistance monitoring device 40A of FIG. 40B Equipped with.

[0073] The insulation resistance monitoring device 40B includes a controller 46B instead of the controller 46A of the insulation resistance monitoring device 40A of FIG.

[0074] The timer 48 measures the time that has elapsed since the three-phase motor device 30A stopped.

[0075] The controller 46B starts or stops the timer 48 based on information from the operation information receiving unit 44. When the three-phase motor device 30A transitions from a stopped state to an operating state, the controller 46B starts the timer 48 to measure time. When the three-phase motor device 30A transitions from an operating state to a stopped state, the controller 46B stops and resets the timer 48 to measure time. When the three-phase motor device 30A is stopped, a predetermined time period T0 has elapsed since the three-phase motor device 30A was stopped, the humidity in the vicinity of the three-phase motor device 30A is equal to or higher than a threshold value Th1, and the temperature in the vicinity of the three-phase motor device 30A is equal to or higher than a threshold value Th2, the controller 46B controls the insulation resistance calculator 42 to measure and output the insulation resistance value Ro of the three-phase motor device 30A. The time period T0 is set, for example, to several minutes to several hours so that the temperature in the vicinity of the three-phase motor device 30A, which has risen during the operation of the three-phase motor device 30A, is sufficiently reduced.

[0076] Generally, the three-phase motor device 30A generates heat during operation, so the temperature in the vicinity of the three-phase motor device 30A rises during operation of the three-phase motor device 30A, and the humidity drops as the temperature rises. Therefore, if the insulation resistance value Ro is measured immediately after the three-phase motor device 30A is stopped, there is a risk that the insulation resistance value Ro obtained will be temporarily increased due to the decreased humidity. In contrast, if the insulation resistance value Ro is measured after a time period T0 has elapsed since the three-phase motor device 30A was stopped, a sufficiently low insulation resistance value Ro can be obtained.

[0077] [Operation example of the third embodiment] Fig. 9 is an exemplary timing chart showing the measurement of the insulation resistance value Ro of the three-phase motor device 30 by the insulation resistance monitoring device 40B of Fig. 8. In the example of Fig. 9, even if the humidity and temperature in the vicinity of the three-phase motor device 30A become higher than the threshold values ​​Th1 and Th2, respectively, after the three-phase motor device 30A stops at time t2, the insulation resistance value Ro of the three-phase motor device 30A is not measured and output until the time period T0 has elapsed (i.e., time t31). Also, even if the time period T0 has elapsed after the three-phase motor device 30A stops at time t2, the humidity and temperature in the vicinity of the three-phase motor device 30A are not measured and output until they become higher than the threshold values ​​Th1 and Th2, respectively (i.e., time t32).

[0078] FIG. 10 is a flowchart showing an example of an insulation resistance monitoring process executed by the controller 46B of FIG.

[0079] In step S21, the controller 46B The three-phase motor device 30A If the answer is YES, the process proceeds to step S22, and if the answer is NO, the process proceeds to step S23.

[0080] In step S22, the controller 46B Using the timer 48, the three-phase motor device 30A The elapsed time Tst from when the power supply is stopped is measured.

[0081] In step S23, the controller 46B resets the timer 48.

[0082] In step S24, the controller 46B is a three-phase motor device 30A It is determined whether the elapsed time Tst since the device was stopped has reached a predetermined time period T0 or more, and if YES, the process proceeds to step S25, and if NO, the process returns to step S21.

[0083] Steps S25 to S29 are similar to steps S12 to S16 in FIG.

[0084] According to the insulation resistance monitoring process of FIG. 10, it is possible to avoid measuring and outputting the insulation resistance value Ro of the three-phase motor device 30A when the humidity decreases due to heat generation by the three-phase motor device 30A, thereby making it possible to measure the insulation resistance value Ro of the three-phase motor device 30A with high accuracy and present it to the user.

[0085] [Effects of the third embodiment] According to the insulation resistance monitoring device 40B of the third embodiment, it is possible to avoid measuring and outputting the insulation resistance value Ro of the three-phase motor device 30A when the humidity decreases due to heat generation by the three-phase motor device 30A, thereby making it possible to measure the insulation resistance value Ro of the three-phase motor device 30A with high accuracy and present it to the user.

[0086] [Fourth embodiment] Next, an insulation resistance monitoring device according to a fourth embodiment will be described.

[0087] [Configuration example of the fourth embodiment] 11 is a block diagram showing an example of the configuration of a motor system including an insulation resistance monitoring device 40C according to a fourth embodiment. The motor system of FIG. 11 includes an insulation resistance monitoring device 40C instead of the insulation resistance monitoring device 40B of FIG.

[0088] The insulation resistance monitoring device 40C includes a controller 46C and a timer 48C instead of the controller 46B and the timer 48 of the insulation resistance monitoring device 40B of FIG.

[0089] The timer 48C measures the elapsed time from the start of a threshold value setting process, which will be described later with reference to FIGS.

[0090] The storage device 49 stores the insulation resistance value Ro of the three-phase motor device 30A measured by an insulation resistance measuring device, and the humidity and temperature in the vicinity of the three-phase motor device 30A acquired when measuring the insulation resistance value Ro of the three-phase motor device 30A. The storage device 49 may store, for example, a table which will be described with reference to FIG.

[0091] The controller 46C controls the insulation resistance measuring instrument to measure the insulation resistance of the object to be measured over a predetermined time period T1. Next, the controller 46C stores in the storage device 49 the humidity and temperature in the vicinity of the object to be measured, which were obtained when the insulation resistance value Ro of the object to be measured was measured, together with the insulation resistance value Ro of the object to be measured by the insulation resistance measuring instrument. Next, the controller 46C selects the humidity corresponding to the minimum insulation resistance value Ro among the multiple insulation resistance values ​​Ro stored in the storage device 49 as the threshold value Th1. The controller 46C also selects the temperature corresponding to the minimum insulation resistance value Ro among the multiple insulation resistance values ​​Ro stored in the storage device 49 as the threshold value Th2. In this way, the controller 46C sets the humidity threshold value Th1 and the temperature threshold value Th2. The time period T1 is set to a length sufficient to obtain a sufficient number of combinations of insulation resistance values ​​Ro, humidity, and temperature to set the threshold values ​​Th1 and Th2, for example, several days to several weeks.

[0092] [Operation example of the fourth embodiment] Fig. 12 is an exemplary timing chart showing the measurement of the insulation resistance of the three-phase motor device 30A by the insulation resistance monitoring device 40C of Fig. 11. When the three-phase motor device 30A is stopped, the insulation resistance monitoring device 40C measures the insulation resistance value Ro every time the humidity or temperature changes by a predetermined step width. In the example of Fig. 12, the humidity step width is 10%, and the temperature step width is 5°C. In the example of Fig. 12, the insulation resistance monitoring device 40C measures the insulation resistance value Ro at times t41 to t46. In this way, the insulation resistance monitoring device 40C obtains a plurality of insulation resistance values ​​Ro measured corresponding to different combinations of humidity and temperature.

[0093] FIG. 13 is a table showing insulation resistance values ​​Ro of the three-phase motor device 30A measured under various humidity and temperature conditions by the insulation resistance monitoring device 40C of FIG. 11. The insulation resistance monitoring device 40C measures the insulation resistance value Ro, for example, every time the combination of humidity and temperature reaches a value corresponding to an unmeasured insulation resistance value Ro, and stores the measured insulation resistance value Ro in association with the humidity and temperature in the storage device 49. After a predetermined time period, for example, three days, has elapsed, the data shown in FIG. 13 is stored in the storage device 49. In FIG. 13, the unit of the insulation resistance value Ro is MΩ, and a blank space indicates that the insulation resistance value Ro has not been measured. In the example of FIG. 13, the minimum value of the insulation resistance value Ro is 100 MΩ, and corresponding to this, the humidity threshold value Th1 is set to 50% and the temperature threshold value Th2 is set to 25°C.

[0094] FIG. 14 is a flowchart showing an example of an insulation resistance monitoring process executed by the controller 46C of FIG.

[0095] In step S31, the controller 46C determines whether the threshold values ​​Th1 and Th2 have not yet been set, and if YES, the process proceeds to step S32, and if NO, the process proceeds to step S33.

[0096] In step S32, the controller 46C executes a threshold value setting process, which will be described later with reference to FIG.

[0097] In step S33, the controller 46C The insulation resistance measurement process in step S33 is similar to the insulation resistance monitoring process described with reference to FIG.

[0098] FIG. 15 is a flowchart showing a subroutine of the threshold setting process in step S32 of FIG.

[0099] In step S41, the controller 46C The three-phase motor device 30A If the answer is YES, the process proceeds to step S42, and if the answer is NO, the process repeats step S41.

[0100] In step S42, the controller 46C The humidity information receiving unit 45 receives the humidity information from the three-phase motor device. 30A The humidity H in the vicinity of the three-phase motor device is acquired from the temperature information receiving unit 47. 30A In step S43, the controller 46C determines whether or not the insulation resistance value Ro corresponding to the current humidity H and temperature T has not yet been measured, and if YES, proceed to step S44, and if NO, return to step S41.

[0101] In step S44, the controller 46C In step S45, the controller 42 controls the insulation resistance calculator 42 to measure the insulation resistance value Ro. 46C The insulation resistance value Ro is stored in the storage device 49 together with the humidity H and the temperature T.

[0102] In step S46, the controller 46C determines whether or not a predetermined measurement period T1 has elapsed since the start of the threshold value setting process, and if YES, the process proceeds to step S47, and if NO, the process returns to step S41.

[0103] In step S47, the controller 46C In step S48, the controller 10 sets the humidity H corresponding to the minimum insulation resistance value Ro as the threshold value Th1. 46C sets the temperature T corresponding to the minimum insulation resistance value Ro as the threshold value Th2.

[0104] Step S32 is executed, for example, at the first operation of the insulation resistance monitoring device 40C after the motor system is installed. After executing step S32, the insulation resistance measurement process of step S33 can be executed using the set threshold values ​​Th1 and Th2.

[0105] When multiple insulation resistance values ​​having the same minimum value are measured, the minimum humidity among the multiple humidities corresponding to these insulation resistance values ​​may be selected as threshold value Th1, and the minimum temperature among the multiple temperatures corresponding to these insulation resistance values ​​may be selected as threshold value Th2.

[0106] 14, by executing the threshold setting process in step S32, it is possible to automatically set an appropriate humidity threshold value Th1 and a temperature threshold value Th2 according to the surrounding environment of the three-phase motor device 30A, and it is possible to measure the insulation resistance value Ro of the three-phase motor device 30A with high accuracy. Furthermore, by automatically setting the threshold values ​​Th1 and Th2, it is possible to reduce the user's trouble.

[0107] When the environment around the three-phase motor device 30A changes after the threshold setting process in step S32 is executed, for example, when the average humidity and average temperature (air temperature) drop due to a change in season, the humidity and temperature near the three-phase motor device 30A may not reach the threshold values ​​Th1 and Th2 easily. This may cause the insulation resistance value Ro of the three-phase motor device 30A to be unable to be measured for a long period of time. For this reason, when the insulation resistance value Ro of the three-phase motor device 30A cannot be measured for a long period of time, the threshold values ​​Th1 and Th2 are reset as described with reference to FIG.

[0108] FIG. 16 is a flowchart showing a modified example of the insulation resistance monitoring process executed by the controller 46C of FIG.

[0109] In step S51, the controller 46C If the result is YES, the process proceeds to step S52, and if the result is NO, the process proceeds to step S53. The threshold value T2 is set to, for example, one week.

[0110] In step S52, the controller 46C The threshold resetting process in step S52 is similar to the threshold setting process in step S32.

[0111] In step S53, the controller 46C The insulation resistance measurement process in step S53 is similar to the insulation resistance monitoring process described with reference to Fig. 4, Fig. 7, or Fig. 10, except that the insulation resistance measurement process proceeds to step 51 in Fig. 16 instead of returning to the first step in the insulation resistance monitoring process in Fig. 4, Fig. 7, or Fig. 10.

[0112] According to the insulation resistance monitoring process of FIG. 16, even if the environment surrounding the three-phase motor device 30A changes, by resetting the threshold values ​​Th1 and Th2, it is possible to prevent the insulation resistance value Ro of the three-phase motor device 30A from being unable to be measured for a long period of time.

[0113] [Effects of the fourth embodiment] According to the insulation resistance monitoring device 40C of the fourth embodiment, by executing the insulation resistance monitoring process of Fig. 14, it is possible to automatically set the humidity threshold value Th1 and the temperature threshold value Th2 appropriate for the surrounding environment of the three-phase motor device 30A, and it is possible to measure the insulation resistance value Ro of the three-phase motor device 30A with high accuracy. Also, according to the insulation resistance monitoring device 40C of the fourth embodiment, by executing the insulation resistance monitoring process of Fig. 16, it is possible to automatically reset the humidity threshold value Th1 and the temperature threshold value Th2 appropriate for the surrounding environment of the three-phase motor device 30A. This makes it possible to prevent a situation in which the insulation resistance value Ro of the three-phase motor device 30A cannot be measured for a long period of time even if the surrounding environment of the three-phase motor device 30A changes.

[0114] [Other variations] Although the embodiment of the present disclosure has been described in detail above, the above description is merely an example of the present disclosure in every respect. It goes without saying that various improvements and modifications can be made without departing from the scope of the present disclosure. For example, the following modifications are possible. In the following, the same reference numerals are used for the same components as in the above embodiment, and the description of the same points as in the above embodiment is omitted as appropriate. The following modifications can be combined as appropriate.

[0115] The humidity sensor 36 may be provided inside the housing 34 as shown in Fig. 1 and other figures, or may alternatively be provided outside the housing 34 as long as it can detect the humidity that affects the insulation resistance value Ro of the three-phase motor device 30, 30A. Similarly, the temperature sensor 37 may be provided inside the housing 34 as shown in Fig. 5 and other figures, or may alternatively be provided outside the housing 34 as long as it can detect the temperature that affects the insulation resistance value Ro of the three-phase motor device 30A.

[0116] As shown in FIG. 1 and other figures, the operation information receiving unit 44 may receive information indicating that the three-phase motor device 30, 30A is operating or stopped from the operation sensor 24 provided in the circuit breaker 20, or may instead receive the information from another control device (not shown) that controls the circuit breaker 20. As shown in FIG. 1 and other figures, the humidity information receiving unit 45 may receive the humidity in the vicinity of the three-phase motor device 30, 30A from the humidity sensor 36 provided in the three-phase motor device 30, 30A, or may instead receive the humidity from another measurement device that measures the humidity in the vicinity of the three-phase motor device 30, 30A. As shown in FIG. 5 and other figures, the temperature information receiving unit 47 may receive the temperature in the vicinity of the three-phase motor device 30A from the temperature sensor 37 provided in the three-phase motor device 30A, or may instead receive the temperature from another measurement device that measures the temperature in the vicinity of the three-phase motor device 30A.

[0117] The insulation resistance monitoring devices 40, 40A to 40C may measure and output the insulation resistance value Ro of the three-phase motor device 30, 30A when the three-phase motor device 30, 30A is stopped and the humidity in the vicinity of the three-phase motor device 30, 30A is within a predetermined range. Also, the insulation resistance monitoring devices 40A to 40C may measure and output the insulation resistance value Ro of the three-phase motor device 30A when the three-phase motor device 30A is stopped and the humidity in the vicinity of the three-phase motor device 30A is within a predetermined range and the temperature in the vicinity of the three-phase motor device 30A is within a predetermined range. In the example of FIG. 13, the minimum value of the insulation resistance value Ro is 100 MΩ, so the humidity range is set to 50 to 56% and the temperature range is set to 25 to 29°C correspondingly. When the environment around the three-phase motor device 30A changes, for example, when the average humidity and average temperature (air temperature) rise, the humidity and temperature around the three-phase motor device 30A tend to exceed the predetermined humidity and temperature ranges. In this case, similar to the insulation resistance monitoring process of Fig. 16, the humidity range and temperature range can be automatically reset to an appropriate range according to the environment around the three-phase motor device 30A. This makes it possible to prevent the insulation resistance value Ro of the three-phase motor device 30A from being unable to be measured for a long period of time.

[0118] In the third embodiment, the insulation resistance monitoring device 40B acquires both the humidity and the temperature in the vicinity of the three-phase motor device 30A, but it may acquire only one of the humidity and the temperature. In this case, the insulation resistance monitoring device 40B measures and outputs the insulation resistance value Ro of the three-phase motor device 30A when the three-phase motor device 30A is stopped, a predetermined time period T0 has elapsed since the three-phase motor device 30A stopped, and the humidity or temperature in the vicinity of the three-phase motor device 30A is equal to or higher than a threshold value.

[0119] In the fourth embodiment, a case has been described in which the insulation resistance monitoring device 40C automatically sets both the humidity threshold value Th1 and the temperature threshold value Th2, but it is also possible to automatically set only one of the threshold values ​​Th1 and Th2.

[0120] The insulation resistance monitoring devices 40, 40A to 40C in FIG. 1 are not limited to an insulation resistance calculator including a current measuring device 41, an insulation resistance calculator 42, a display device 43, a voltage source E1, and a switch SW, and may include an insulation resistance calculator having any other configuration.

[0121] The display device 43 may be provided in a remote device connected via a communication line, instead of inside the insulation resistance monitoring device 40, 40A to 40C.

[0122] The calculation results and judgment results of the insulation resistance calculator 42 may be audibly output using an audio output device instead of visually outputting them using the display device 43. Any other output device may be used to notify the user of the calculation results and judgment results of the insulation resistance calculator 42. The insulation resistance monitoring devices 40, 40A to 40C may output the calculation results and judgment results of the insulation resistance calculator 42 to another device connected via a communication line.

[0123] In the embodiment described above, the insulation resistance monitoring devices 40, 40A to 40C are connected to node N4 and housing 34 of the three-phase motor device 30, 30A, but the insulation resistance monitoring devices 40, 40A to 40C may also be connected between node N5 and housing 34, or between node N6 and housing 34.

[0124] The insulation resistance monitoring devices 40, 40A to 40C may be connected between two mutually insulated nodes of any other object to be measured instead of the three-phase motor devices 30, 30A. The object to be measured includes, for example, a power supply device, a timer, a relay, a common socket, a DIN rail, a waterproof cover, a temperature regulator, a switch, etc. Also, the insulation resistance monitoring device 40 may be connected to any two mutually insulated nodes of the object to be measured, not limited to the power line and the ground conductor of the object to be measured.

[0125] [summary] An insulation resistance monitoring device according to each aspect of the present disclosure may be expressed as follows.

[0126] An insulation resistance monitoring device 40 according to one aspect of the present disclosure includes an insulation resistance measuring device, an operation information receiving unit 44, a humidity information receiving unit 45, and a controller 46. The insulation resistance measuring device measures and outputs the insulation resistance of the object to be measured. The operation information receiving unit 44 receives information indicating that the object to be measured is operating or stopped. The humidity information receiving unit 45 receives the humidity in the vicinity of the object to be measured. The controller 46 controls the insulation resistance measuring device to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped and the humidity in the vicinity of the object to be measured is equal to or higher than a first threshold value Th1.

[0127] An insulation resistance monitoring device 40B according to one aspect of the present disclosure further includes a timer that measures the elapsed time since the object to be measured has stopped. When the object to be measured is stopped, a predetermined first time period has elapsed since the object to be measured stopped, and the humidity near the object to be measured is equal to or higher than a first threshold value Th1, a controller 46B controls the insulation resistance measuring device to measure and output the insulation resistance of the object to be measured.

[0128] An insulation resistance monitoring device 40C according to one aspect of the present disclosure further includes a storage device 49 that stores the insulation resistance of the object to be measured measured by the insulation resistance measuring device. A controller 46C sets a first threshold value Th1 by controlling the insulation resistance measuring device to measure the insulation resistance of the object to be measured over a second predetermined time period, storing in the storage device 49 the humidity in the vicinity of the object to be measured that was received when the insulation resistance of the object to be measured was measured together with the insulation resistance of the object to be measured measured by the insulation resistance measuring device, and selecting the humidity corresponding to the smallest insulation resistance among the multiple insulation resistances stored in the storage device 49 as the first threshold value Th1.

[0129] According to an insulation resistance monitoring device 40C according to one aspect of the present disclosure, a controller 46C sets the first threshold value Th1 when the period during which the humidity near the object to be measured is less than the first threshold value Th1 exceeds a predetermined third time period.

[0130] An insulation resistance monitoring device 40A according to one aspect of the present disclosure further includes a temperature information receiving unit that receives a temperature near the object to be measured. A controller 46A controls the insulation resistance measuring device to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped, the humidity near the object to be measured is equal to or higher than a first threshold value Th1, and the temperature near the object to be measured is equal to or higher than a second threshold value Th2.

[0131] An insulation resistance monitoring device 40B according to one aspect of the present disclosure further includes a timer that measures the elapsed time since the object to be measured has stopped. A controller 46B controls the insulation resistance measuring device to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped, a predetermined first time period has elapsed since the object to be measured stopped, the humidity near the object to be measured is equal to or greater than a first threshold value Th1, and the temperature near the object to be measured is equal to or greater than a second threshold value Th2.

[0132] An insulation resistance monitoring device 40C according to one aspect of the present disclosure further includes a storage device 49 that stores the insulation resistance of the object measured by the insulation resistance measuring device. A controller 46C sets a second threshold value Th2 by controlling the insulation resistance measuring device to measure the insulation resistance of the object for a second predetermined time period, storing in the storage device 49 the temperature in the vicinity of the object received when the insulation resistance of the object is measured together with the insulation resistance of the object measured by the insulation resistance measuring device, and selecting the temperature corresponding to the smallest insulation resistance among the multiple insulation resistances stored in the storage device 49 as the second threshold value Th2.

[0133] According to an insulation resistance monitoring device 40C according to one aspect of the present disclosure, a controller 46C sets the second threshold value Th2 when the period during which the temperature in the vicinity of the object to be measured is below the second threshold value Th2 exceeds a predetermined third time period. [Industrial Applicability]

[0134] According to an insulation resistance monitoring device according to one aspect of the present invention, it is possible to measure the insulation resistance of an object to be measured with high accuracy, taking into account fluctuations in insulation resistance caused by the environment surrounding the object to be measured. [Explanation of symbols]

[0135] 10 Three-phase AC power supply 11~13 Single-phase AC power supply 20 Circuit Breaker 21~23 Switch 24 Motion Sensor 30,30A three-phase motor device 31~33 Windings 34 Case 35 Earth insulation resistance 36 Humidity Sensor 37 Temperature Sensor 40, 40A~40C Insulation resistance monitor 41 Current measuring device 42 Insulation Resistance Calculator 43 Display device 44 Operation information receiving unit 45 Humidity information receiver 46, 46A~46C Controller 47 Temperature information receiving unit 48,48C Timer 49 Storage device E1 Voltage source SW Switch

Claims

1. an insulation resistance measuring instrument for measuring and outputting the insulation resistance of an object to be measured; a storage device for storing the insulation resistance of the object to be measured measured by the insulation resistance measuring instrument; an operation information receiving unit for receiving information indicating that the object to be measured is in operation or stopped; a humidity information receiving unit that receives the humidity in the vicinity of the object to be measured; a controller for controlling the insulation resistance measuring instrument so as to measure and output an insulation resistance of the object to be measured when the object to be measured is stopped and the humidity in the vicinity of the object to be measured is equal to or higher than a first threshold value; The controller: controlling the insulation resistance tester to measure the insulation resistance of the device under test for a second predetermined time period; storing in the storage device the humidity in the vicinity of the object to be measured, which is received when the insulation resistance of the object to be measured is measured together with the insulation resistance of the object to be measured by the insulation resistance measuring instrument; selecting a humidity corresponding to a minimum insulation resistance among the plurality of insulation resistances stored in the storage device as the first threshold value; Setting the first threshold value; Insulation resistance monitoring device.

2. The insulation resistance monitoring device further includes a timer that measures an elapsed time after the object to be measured has stopped, the controller controls the insulation resistance measuring instrument to measure and output an insulation resistance of the object to be measured when the object to be measured is stopped, a predetermined first time period has elapsed since the object to be measured was stopped, and humidity in the vicinity of the object to be measured is equal to or higher than the first threshold value.

2. The insulation resistance monitoring device according to claim 1.

3. the controller sets the first threshold value when a period during which the humidity in the vicinity of the object to be measured is less than the first threshold value exceeds a third predetermined time period.

3. The insulation resistance monitoring device according to claim 1 or 2.

4. The insulation resistance monitoring device further includes a temperature information receiving unit that receives a temperature in the vicinity of the object to be measured, the controller controls the insulation resistance measuring instrument to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped, the humidity in the vicinity of the object to be measured is equal to or higher than the first threshold value, and the temperature in the vicinity of the object to be measured is equal to or higher than the second threshold value. An insulation resistance monitoring device according to any one of claims 1 to 3.

5. The insulation resistance monitoring device further includes a timer that measures an elapsed time after the object to be measured has stopped, the controller controls the insulation resistance measuring instrument to measure and output the insulation resistance of the object to be measured when the object to be measured is stopped, a predetermined first time period has elapsed since the object to be measured was stopped, the humidity in the vicinity of the object to be measured is equal to or higher than the first threshold value, and the temperature in the vicinity of the object to be measured is equal to or higher than the second threshold value.

5. The insulation resistance monitoring device according to claim 4.

6. The controller, controlling the insulation resistance tester to measure the insulation resistance of the device under test for a second predetermined time period; storing in the storage device the insulation resistance of the object measured by the insulation resistance measuring instrument and a temperature in the vicinity of the object received when the insulation resistance of the object was measured; selecting a temperature corresponding to a minimum insulation resistance among the plurality of insulation resistances stored in the storage device as the second threshold value; setting the second threshold value; 6. The insulation resistance monitoring device according to claim 4 or 5.

7. the controller sets the second threshold value when a period during which the temperature in the vicinity of the object to be measured is less than the second threshold value exceeds a predetermined third time period.

7. The insulation resistance monitoring device according to claim 6.

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