Insulation monitoring device and control method thereof

Abstract

This invention relates to an insulation monitoring device, comprising: a signal generation unit that generates a measurement signal having a preset voltage and applies the measurement signal to ground through a protective conductor connected to one end of the signal generation unit; a coupling resistor connected to the transmission line; a signal detection unit that includes a detection resistor disposed between the coupling resistor and the other end of the signal generation unit, and detects the voltage of the measurement signal distributed in the internal resistance of the insulation monitoring device formed by the coupling resistor and the detection resistor based on the voltage difference across the detection resistor; and a control unit that detects transient voltages caused by the charging and discharging of a system capacitor formed by parasitic capacitance between the transmission line and the ground from the voltage detected by the signal detection unit, and confirms the connection status of the insulation monitoring device to the transmission line and the ground based on the result of detecting the transient voltage.

Description

Technical Field

[0001] This invention relates to an insulation monitoring device and a control method for the insulation monitoring device in an ungrounded (IT) power system for preventing accidents by detecting grounding faults and the like in advance. Background Technology

[0002] An IT (Insulation Terra) grounding method is a grounding method where neither side of the transmission line is grounded, but only through the load's casing. In this type of ungrounded system (IT system), the fault current is extremely small when a ground fault occurs, making it difficult to detect with grounding detection devices used in grounding systems. Especially in the case of DC (direct current) systems used in solar energy systems or ESS (Energy Storage System), insulation monitoring devices (IMDs) are emerging as a solution for measuring the insulation status of such ungrounded systems.

[0003] A typical insulation monitoring device (IMD) is formed between the ground and the transmission line, measuring the insulation state between the ground and the transmission line by measuring an imaginary insulation resistance formed between the transmission line and the ground. For this purpose, the insulation monitoring device includes: a signal generation unit that generates a signal applied to the ground through the ground; and a detection resistor for detecting the voltage of the signal generated in the signal generation unit. Furthermore, it has a structure that detects the insulation state between the transmission line and the ground by detecting the voltage difference across the detection resistor and calculating the magnitude of the insulation resistance.

[0004] On the other hand, as described above, the insulation monitoring device determines the insulation status between the transmission line and the ground by the magnitude of the insulation resistance. If the voltage drop caused by the insulation resistance (the voltage detected by the detection resistor) is greater, i.e., the insulation resistance is smaller, the insulation status is considered worse. If the insulation resistance is below a specified value, it is detected that the insulation status has been breached and a grounding has occurred. Conversely, if the detected voltage is smaller, i.e., the insulation resistance is larger, the insulation status is considered better.

[0005] However, if the connection between the insulation monitoring device and the transmission line or ground is broken—for example, if there is a break in the connection between the insulation monitoring device and the transmission line, or a break in the connection between the insulation monitoring device and ground—the circuit connecting the transmission line and ground to the insulation monitoring device via insulation resistance may be open. Thus, the resistance between the two ends of the broken circuit can be infinitely large. In this case, due to the break, the voltage of the signal generated in the signal generation unit may not be detectable. Furthermore, this can be similar to the case where the insulation resistance is very large, i.e., the insulation condition of the transmission line is very good.

[0006] Therefore, conventional insulation monitoring devices have the problem of failing to detect breaks in the transmission line and / or ground connection between the device and the insulation monitoring system. Furthermore, as mentioned above, in the event of a break in the transmission line and / or ground connection between the device and the insulation monitoring system, the insulation condition of the transmission line cannot be monitored due to the impact of the break. That is, even if an actual grounding event occurs due to insulation failure, the insulation monitoring device may determine that the insulation resistance is very high, thus leading to the misjudgment that the insulation condition of the transmission line is good. Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The purpose of this invention is to solve the above-mentioned problems and other problems, and to provide an insulation monitoring device and a control method for the insulation monitoring device that can detect whether there is a break in the connection between the transmission line and the insulation monitoring device by confirming the connection status between the insulation monitoring device and the transmission line.

[0009] Furthermore, the present invention aims to provide an insulation monitoring device and a control method for the insulation monitoring device capable of confirming the connection status of each of a plurality of transmission lines with the insulation monitoring device.

[0010] In addition, the present invention aims to provide an insulation monitoring device and a control method for the insulation monitoring device, which can detect whether there is a break in the connection between the insulation monitoring device and the ground by confirming the connection status between the insulation monitoring device and the ground.

[0011] Furthermore, the present invention aims to provide an insulation monitoring device and a control method thereof that can confirm the connection between the insulation monitoring device and the load housing when the insulation monitoring device is separated from the system, and can notify the manager of the connection status between the load housing and the insulation monitoring device.

[0012] Technical solutions to the problem

[0013] To achieve the above or other objectives, according to one aspect of the present invention, an insulation monitoring device according to an embodiment of the present invention is characterized by comprising: a signal generation unit that generates a measurement signal having a preset voltage and applies the measurement signal to the ground through a protective conductor connected to one end of the signal generation unit; a coupling resistor connected to the transmission line; a signal detection unit that includes a detection resistor disposed between the coupling resistor and the other end of the signal generation unit, and detects the voltage of the measurement signal distributed in the internal resistance of the insulation monitoring device formed by the coupling resistor and the detection resistor based on the voltage difference across the detection resistor; and a control unit that detects transient voltages caused by the charging and discharging of a system capacitor formed by parasitic capacitance between the transmission line and the ground from the voltage detected by the signal detection unit, and confirms the connection status of the insulation monitoring device with the transmission line and the ground based on the result of detecting the transient voltage.

[0014] In one embodiment, the control unit detects a normal state voltage from the voltage detected by the signal detection unit, and detects a voltage that is greater than or equal to a preset value than the detected normal state voltage as the transient voltage.

[0015] In one embodiment, the control unit detects the transient voltage from the voltage detected by the signal detection unit at a preset time period, the preset time being determined based on at least one of the shape of the measurement signal and the period of the measurement signal.

[0016] In one embodiment, the control unit determines a sampling period based on a preset time constant, calculates a plurality of average voltages of a plurality of voltages detected by the signal detection unit in each sampling period, and detects the normal state voltage based on the differences between the calculated plurality of average voltages.

[0017] In one embodiment, when a voltage greater than a preset value than the normal state voltage is detected, the control unit detects whether the magnitude of the detected voltage changes by a predetermined value within a predetermined time period, and further determines whether the transient voltage has been generated based on the change in the magnitude of the detected voltage.

[0018] In one embodiment, the system further includes a communication unit that communicates with a pre-defined server or terminal. The control unit controls the communication unit to send a notification message to the server or terminal indicating that the connection status of the insulation monitoring device is abnormal, based on the result of detecting the transient voltage.

[0019] The control method of the insulation monitoring device according to an embodiment of the present invention is characterized by comprising: generating a measurement signal having a preset voltage and applying the measurement signal to the ground; detecting the voltage of the measurement signal distributed in the internal resistance of the insulation monitoring device formed by the coupling resistor connected to the transmission line and the detection resistor according to a preset detection resistor; determining whether the voltage detected by the detection resistor is a normal state voltage; if the voltage detected by the detection resistor is a normal state voltage, detecting whether a transient voltage has been generated within a preset time period based on the voltage detected by the detection resistor; and determining the connection state of the insulation monitoring device with the transmission line and the ground according to whether the transient voltage has been generated.

[0020] In one embodiment, the step of detecting whether the transient voltage has been generated includes: calculating the voltage difference between the voltage detected by the detection resistor and the normal state voltage; comparing the calculated voltage difference with a preset voltage value; detecting that the transient voltage has been generated if the comparison result is that the calculated voltage difference is greater than or equal to the preset voltage value; and detecting that the transient voltage has not been generated if the comparison result is that the calculated voltage difference is less than or equal to the preset voltage value.

[0021] In one embodiment, the step of determining whether it is the normal state voltage includes: determining a sampling period based on a preset time constant; calculating the average voltage of a plurality of voltages detected during the sampling period; calculating the difference between the average voltage and the average voltage of a plurality of voltages detected in a previous sampling period; comparing the calculated difference with a preset error; and, based on the comparison result, determining the average voltage of the plurality of voltages detected during the sampling period as the normal state voltage, or repeating the steps of determining the sampling period, calculating the average voltage, calculating the difference of the average voltage, and comparing the preset error.

[0022] In one embodiment, the step of determining the connection status of the insulation monitoring device with the transmission line and the ground further includes: if no transient voltage is generated within the preset time, sending a notification message to a preset server or terminal indicating that the connection status of the insulation monitoring device is abnormal.

[0023] The insulation monitoring device of this invention is characterized by comprising: a signal generation unit that generates a measurement signal having a preset voltage and applies the measurement signal to the ground through a protective conductor connected to one end of the signal generation unit; a coupling resistor connected to the transmission line; a signal detection unit that includes a detection resistor disposed between the coupling resistor and the other end of the signal generation unit, and detects the voltage of the measurement signal distributed in the internal resistance of the insulation monitoring device formed by the coupling resistor and the detection resistor based on the voltage difference across the detection resistor; a circuit switching switch that connects or disconnects the connection between the coupling resistor and the detection resistor; and a control unit that controls the circuit switching switch and detects whether a second voltage detected by the signal detection unit when the coupling resistor and the detection resistor are connected includes a transient voltage based on a first voltage detected by the signal detection unit when the connection between the coupling resistor and the detection resistor is disconnected by the circuit switching switch, and confirms the connection state of the insulation monitoring device with the transmission line and the ground based on the result of detecting the transient voltage.

[0024] In one embodiment, the first voltage is a preset bias voltage applied to the signal detection unit. When the second voltage is greater than the bias voltage by a preset voltage value, the control unit determines that the second voltage includes the transient voltage.

[0025] In one embodiment, the transmission line includes a plurality of lines, the coupling resistor is connected to the plurality of lines respectively, and the circuit switching is formed by a plurality of switches formed between the coupling resistors and the detection resistor, which are different from each other and are respectively connected to the plurality of lines.

[0026] In one embodiment, the control unit controls all of the plurality of switches to detect the voltage detected by the signal detection unit when the connection between each coupling resistor and the detection resistor is interrupted as the first voltage. The control unit selects and controls a first switch among the plurality of switches to connect the first coupling resistor connected to the first switch and the detection resistor. When the first coupling resistor and the detection resistor are connected to each other, the control unit detects the voltage detected by the signal detection unit as the second voltage. Based on the first voltage, the control unit detects whether the second voltage includes the transient voltage. Based on whether the transient voltage is included, the control unit confirms the connection status of any one of the plurality of lines connected to the first coupling resistor with the insulation monitoring device.

[0027] In one embodiment, the system further includes a communication unit that communicates with a pre-defined server or terminal. The control unit controls the communication unit to send a notification message to the server or terminal indicating an abnormal connection status of the insulation monitoring device based on the result of detecting the transient voltage. The notification message includes information about the connection status of any one of the lines and the insulation monitoring device.

[0028] In one embodiment, it further includes: a housing terminal connected to the housing of the load; and a housing grounding switch connected to the sensing resistor, connecting or disconnecting the connection between the housing terminal and the sensing resistor.

[0029] In one embodiment, the control unit controls the housing grounding switch to disconnect the connection between the housing terminal and the detection resistor while the connection between the coupling resistor and the detection resistor is disconnected by the circuit switch; while the connection between the housing terminal and the detection resistor is disconnected, the control unit detects a bias voltage based on the voltage detected by the signal detection unit; the control unit controls the housing grounding switch to connect the housing terminal and the detection resistor while the connection between the coupling resistor and the detection resistor is disconnected by the circuit switch; while the housing terminal and the detection resistor are connected, the control unit further confirms the connection status of the load housing and the insulation monitoring device based on the result of comparing the voltage detected by the signal detection unit with the bias voltage.

[0030] In the control method of the insulation monitoring device according to an embodiment of the present invention, the insulation monitoring device includes: a circuit switching switch, which switches between a coupling resistor connected to a transmission line and a preset detection resistor; and a signal detection unit having the detection resistor; the control method of the insulation monitoring device is characterized in that it includes:

[0031] The steps include: generating a measurement signal with a preset voltage and applying the measurement signal to ground; controlling the circuit to open and close a switch to disconnect the connection between the coupling resistor and the preset detection resistor; detecting a bias voltage based on the voltage detected by the signal detection unit while the connection between the coupling resistor and the detection resistor is disconnected; controlling the circuit to open and close a switch to connect the coupling resistor and the preset detection resistor; and detecting whether the voltage detected by the signal detection unit contains a transient voltage based on the bias voltage, and determining the connection status of the insulation monitoring device with the transmission line and the ground based on whether the transient voltage is included.

[0032] In one embodiment, the insulation monitoring device further includes: a housing terminal connected to the housing of the load; and a housing grounding switch connected to the detection resistor, connecting or disconnecting the connection between the housing terminal and the detection resistor; the step of disconnecting the connection between the coupling resistor and the preset detection resistor further includes: controlling the housing grounding switch to disconnect the connection between the housing terminal and the detection resistor when the connection between the coupling resistor and the detection resistor is disconnected; detecting a bias voltage based on the voltage detected by the signal detection unit; controlling the housing grounding switch to connect the housing terminal and the detection resistor; comparing the voltage detected by the signal detection unit with the bias voltage; and confirming the connection status between the housing of the load and the insulation monitoring device based on the comparison result.

[0033] In one embodiment, the transmission line includes a plurality of lines, the coupling resistor is connected to the plurality of lines respectively, and the circuit switching includes a plurality of switches formed between each of the different coupling resistors connected to the plurality of lines and the detection resistor. The step of connecting the coupling resistor and the preset detection resistor is to sequentially select any one of the plurality of switches and control the selected switch to connect the coupling resistor connected to the selected switch and the detection resistor. The step of determining the connection status of the insulation monitoring device with the transmission line and the ground is to determine the connection status of any one of the plurality of lines connected to the specific coupling resistor and the insulation monitoring device based on whether the voltage detected by the signal detection unit includes the transient voltage when the specific coupling resistor and the detection resistor are connected to each other.

[0034] In one embodiment, the step of determining the connection status of the insulation monitoring device with the transmission line and the ground further includes: sending a notification message to a pre-set server or terminal indicating that the connection status of the insulation monitoring device is abnormal, based on whether the transient voltage is present; the notification message includes information about the connection status of each of the plurality of lines with the insulation monitoring device.

[0035] Invention Effects

[0036] The insulation monitoring device and its control method of the present invention will be described below.

[0037] According to at least one embodiment of the present invention, the effect of the present invention is that by detecting whether there is a break in the connection between the transmission line and the insulation monitoring device or between the ground and the insulation monitoring device, the insulation status of the transmission line can be prevented from being erroneously detected due to the break in the connection.

[0038] In addition, the present invention has the advantage that by notifying when a disconnection is detected between the transmission line and the insulation monitoring device or between the ground and the insulation monitoring device, the manager can be aware that the insulation monitoring device is in a state where it cannot detect the grounding of the ungrounded system due to the disconnection.

[0039] Furthermore, the advantage of this invention is that by detecting the connection status between each of the plurality of transmission lines and the insulation monitoring device, the disconnection can be detected even if any of the plurality of transmission lines is disconnected from the insulation monitoring device.

[0040] In addition, the advantage of the present invention is that by confirming the connection between the insulation monitoring device and the load housing and notifying the connection status between the insulation monitoring device and the load housing, it is possible to prevent electric shock accidents caused by the load housing in the event of a leakage current accident. Attached Figure Description

[0041] Figure 1 This is a block diagram illustrating the configuration of an insulation monitoring device according to an embodiment of the present invention.

[0042] Figure 2a This is a flowchart illustrating the operation process of the insulation monitoring device of the present invention in confirming the connection status with the transmission line or ground.

[0043] Figure 2b This is a graph illustrating an example of the change in received signal voltage detected by the insulation monitoring device according to an embodiment of the present invention.

[0044] Figure 3 This is a flowchart illustrating the process of determining whether the received signal voltage detected in the insulation monitoring device of this embodiment of the invention contains transient voltage.

[0045] Figure 4 This is a block diagram illustrating the configuration of an insulation monitoring device according to an embodiment of the present invention, which includes a circuit switch for controlling and closing circuits for transmission lines, insulation resistance, and ground connection.

[0046] Figure 5 It is shown that Figure 4 The flowchart shown illustrates the process by which the insulation monitoring device confirms the connection status with the transmission line and the ground and calculates the insulation resistance based on the opening / closing of the circuit switch.

[0047] Figure 6This is a block diagram illustrating the structure of an insulation monitoring device according to an embodiment of the present invention, which is connected to a plurality of transmission lines through a plurality of circuit switching switches.

[0048] Figure 7 This is a conceptual diagram illustrating an example of an insulation monitoring device connected to the housing of a load according to an embodiment of the present invention.

[0049] Figure 8 This is a block diagram illustrating the configuration of an insulation monitoring device according to an embodiment of the present invention, which is capable of confirming the connection of the housing of a load and the grounding state of the housing of the load based on the housing grounding circuit connected via the housing terminal KE.

[0050] Figure 9 This is a flowchart illustrating the operation process of an insulation monitoring device according to an embodiment of the present invention, which uses a casing grounding switch connected to the casing of a load to confirm the connection status of the casing.

[0051] Figure 10 This is an example diagram illustrating the operation of the master-slave switch when the switch of the insulation monitoring device provided in an embodiment of the present invention is configured as a master-slave switch. Detailed Implementation

[0052] It should be noted that the technical terms used in this specification are for illustrative purposes only and are not intended to limit the technical concepts disclosed herein. Furthermore, unless the context clearly indicates otherwise, the singular expressions used in this specification include the plural expressions. The suffixes "module" and "part" used in the following description for the purpose of drafting the specification are assigned or used interchangeably only for ease of writing and do not in themselves have a distinguishing meaning or function from each other.

[0053] In this specification, terms such as “constituting” or “including” should not be construed as including all the constituent elements or steps described in the specification, but should be construed as excluding some constituent elements or steps, or including additional constituent elements or steps.

[0054] In addition, in the process of describing the technology disclosed in this specification, when it is determined that a detailed description of the relevant known technology would obscure the essence of the technology disclosed in this specification, a detailed description thereof is omitted.

[0055] Furthermore, it should be understood that the accompanying drawings are merely for the purpose of facilitating the understanding of the embodiments disclosed in this specification. The technical concepts disclosed in this specification are not limited to the drawings, but rather encompass all modifications, equivalents, and even substitutions included within the scope of the present invention. In addition to the various embodiments described below, combinations of embodiments can also be modifications, equivalents, or substitutions included within the scope of the present invention, and therefore naturally fall within the scope of the present invention.

[0056] Figure 1 This is a block diagram illustrating the configuration of the insulation monitoring device 10 according to an embodiment of the present invention.

[0057] Reference Figure 1 The insulation monitoring device 10 of this embodiment may include a control unit 100, a signal generation unit 110 connected to the control unit 100, a signal detection unit 130 including a detection resistor Rm, an insulation resistance calculation unit 108, and a memory 104. Furthermore, it may also include a communication unit 106.

[0058] Here, one side of the signal generation unit 110 is connected to a protective earth (PE) 120 connecting one end of the signal generation unit 110 to the ground, and the other end of the signal generation unit 110 can be connected to the detection resistor Rm. Furthermore, the detection resistor Rm can be connected to a resistor, i.e., a coupling resistor (Rc) 180, that is connected to each of the lines L1, L2 constituting the transmission line 170.

[0059] Figure 1 The components of the insulation monitoring device 10 shown are not essential for implementing the insulation monitoring device 10. The insulation monitoring device 10 described in this specification may have more or fewer components than those listed above.

[0060] First, the signal generation unit 110 can generate a measurement signal with a preset positive (+) voltage Up or negative (-) voltage Up, under the control of the control unit 100. In this case, the signal generation unit 110 can generate a square wave signal. Furthermore, the signal generation unit 110 can be connected to the ground via the protective conductor 120. Therefore, the measurement signal generated in the signal generation unit 110 can be applied to the ground.

[0061] On the other hand, as mentioned above, an ungrounded system is a system where neither side of the transmission line is grounded, but grounding is achieved only through the load casing. An insulation resistance Re, 140 is provided between the transmission line (L1, L2) 170 and the ground. This insulation resistance 140 can be an imaginary resistance placed between the transmission line 170 and the ground. Furthermore, since both the transmission line 170 and the ground are conductors, parasitic capacitance components may exist between the conductors. As mentioned above, Figure 1 The system capacitor Ce, 150 can refer to the parasitic capacitance component formed between the transmission line 170 and the ground.

[0062] In this configuration, the transmission line 170 and the ground can be connected to each other via the insulation resistance 140. Furthermore, the ground can be connected to one end of the signal generation unit 110 via the protective conductor 120, and the transmission line 170 can be connected to the other end of the signal generation unit 110 via the coupling resistor 180 and the detection resistor Rm. Therefore, a circuit can be formed in which the protective conductor 120, the signal generation unit 110, the detection resistor Rm, the coupling resistor 180, the transmission line 170, and the insulation resistance 140 are connected via the ground. Hereinafter, the circuit formed via the ground and including the transmission line 170 and the insulation resistance 140 will be referred to as an insulated circuit.

[0063] Therefore, the measurement signal applied to the ground can be applied to the transmission line 170 via the insulation circuit and the insulation resistor 140. Furthermore, a coupling resistor 180 and a detection resistor Rm connected to the transmission line 170 can be applied. Therefore, the voltage of the measurement signal that has passed through the insulation resistor 140, the coupling resistor 180, and the detection resistor Rm can be detected in the signal detection unit 130 via the detection resistor Rm.

[0064] On the other hand, the coupling resistor 180 and the detection resistor Rm, i.e., the internal resistance Ri of the insulation monitoring device 10, can form a combined resistance with the insulation resistor 140. Furthermore, the voltage Up of the measured signal can be reduced by the combined resistance. Therefore, the signal detection unit 130 can detect a voltage smaller than the voltage Up of the measured signal. Hereinafter, the signal having a voltage reduced by the combined resistance of the insulation resistor Rm and the internal resistance Ri of the insulation monitoring device 10 will be referred to as the received signal, and the voltage detected in the signal detection unit 130 will be referred to as the voltage Um of the received signal.

[0065] On the other hand, as described above, since the internal resistance Ri of the insulation monitoring device 10 and the insulation resistance 140 form a combined resistance, the voltage Um of the received signal can be the voltage Up of the measured signal distributed on the internal resistance Ri according to the ratio of the insulation resistance 140 and the internal resistance Ri of the insulation monitoring device 10.

[0066] On the other hand, the signal detection unit 130 may include: the detection resistor Rm; an amplification unit for amplifying the voltage across the detection resistor Rm to a measurable level; and an ADC (Analog-to-Digital Converter) for converting the amplified analog voltage value into a digital value. Furthermore, the control unit 100, which receives the received signal voltage converted into a digital value by the signal detection unit 130, can input the received signal voltage Um to the insulation resistance calculation unit 108, and can calculate the magnitude of the insulation resistance 140 using the insulation resistance calculation unit 108.

[0067] The insulation resistance calculation unit 108 can calculate the magnitude of the insulation resistance 140 according to the control of the control unit 100. More specifically, the insulation resistance calculation unit 108 can calculate the insulation resistance 140 based on the fact that the received signal voltage Um is distributed across the internal resistance Ri according to the ratio of the insulation resistance 140 to the internal resistance Ri of the insulation monitoring device 10.

[0068] In this case, although the value of the insulation resistance 140 is unknown, the values ​​of the coupling resistance 180 that forms the combined resistance Ri and the detection resistance Rm can be determined according to the specifications of the insulation monitoring device 10. Therefore, the insulation resistance calculation unit 108 can calculate the value of the insulation resistance 140 based on the detected received signal voltage Um, the internal resistance Ri, and the measured signal voltage Up. Furthermore, the calculated insulation resistance 140 can be returned to the control unit 100.

[0069] The memory 104 stores data supporting various functions of the insulation monitoring device 10. The memory 104 can store data and instructions for the operation of the insulation monitoring device 10. Additionally, the memory 104 can temporarily or permanently store data input to the control unit 100 and data output from the control unit 100. For example, the memory 104 can store data for controlling the insulation resistance calculation unit 108, such as the magnitude of the coupling resistor 180, the magnitude of the detection resistor Rm, information related to the measured signal voltage Up, and the received signal voltage Um received from the signal detection unit 130.

[0070] On the other hand, the communication unit 106 can establish a communication connection with a pre-set server or terminal. Here, the terminal is the terminal of the manager who manages the insulation monitoring device 10, and may include a mobile phone, smartphone, laptop computer, PDA (personal digital assistant), slate PC, tablet PC, ultrabook, wearable device, etc.

[0071] The control unit 100 can determine the insulation status between the transmission line 170 and the ground based on the insulation resistance 140 calculated by the insulation resistance calculation unit 108. For example, if the calculated insulation resistance 140 is above a preset value, the control unit 100 can determine that the insulation status between the transmission line 170 and the ground is good. However, if the calculated insulation resistance 140 is below the preset value, the control unit 100 can determine that the insulation status between the transmission line 170 and the ground is poor. In this case, if the insulation status is below a specified level, the control unit 100 can determine that a grounding fault may have occurred and can notify the manager of suspected insulation failure through the communication unit 106.

[0072] On the other hand, the control unit 100 of the insulation monitoring device 10 in this embodiment of the invention can determine the connection status between the insulation monitoring device 10 and the transmission line 170 or the ground based on the change in the received signal voltage Um. More specifically, the control unit 100 can detect whether the detected received signal voltage Um includes a change caused by the parasitic capacitance formed between the transmission line 170 and the ground, i.e., the system capacitor 150.

[0073] For example, as described above, when a system capacitor 150 is formed between the ground and the transmission line 170, the voltage of the measurement signal applied to the ground can charge the system capacitor 150 before it is applied to the transmission line 170. As a result, during the charging period of the system capacitor 150, the received signal voltage Um rises significantly, and then the voltage charged in the system capacitor 150 gradually decreases as it discharges. Furthermore, this state can be repeated based on square wave pulses. That is, transient voltages where the magnitude of the received signal voltage Um increases significantly over a period of time can be repeatedly generated based on square wave pulses.

[0074] As described above, since the received signal voltage Um suddenly increases under the action of the system capacitor 150 and then stabilizes after a specified time, the insulation resistance calculation unit 108 can detect the normal state voltage, that is, the stable state of the received signal voltage where the voltage change caused by the transient voltage is eliminated, so as to prevent the magnitude of the insulation resistance 140 from being incorrectly calculated due to the transient voltage.

[0075] Therefore, when a transient voltage is detected from the received signal voltage Um, the insulation resistance calculation unit 108 can retain the insulation resistance calculation within a sampling interval determined according to a preset time multiple. Furthermore, it can determine whether the received signal voltage Um has stabilized based on the difference in the average voltage calculated in each sampling interval. More specifically, the insulation resistance calculation unit 108 is configured to detect the average voltage calculated in the current sampling interval as a normal state voltage if the difference between the average voltage calculated in the current sampling interval and the previously calculated average voltage is below a preset error.

[0076] On the other hand, as described above, the transient voltage can be generated during the charging of the system capacitor 150 by the voltage Up of the measured signal. That is, the transient voltage can be generated when the system capacitor 150 is formed between the transmission line 170 and the ground. On the other hand, since the charging of the capacitor takes place between conductors forming the capacitor in a current-flowing circuit, i.e., a closed circuit, the transient voltage can only be generated when a closed insulating circuit is formed between the transmission line 170 and the ground connected to each other by the insulation resistance 140.

[0077] Therefore, the control unit 100 can determine whether the insulation monitoring device 10 is connected to the transmission line 170 or ground by the transient voltage. To this end, the control unit 100 can sense the change in the received signal voltage Um detected by the signal detection unit 130, and can sense whether the transient voltage was generated within a preset time.

[0078] Furthermore, if a transient voltage is generated, it can be determined that the insulation monitoring device 10 is connected to the transmission line 170 or the ground. If no transient voltage is generated, it can be determined that a break has occurred between the transmission line 170 and the insulation monitoring device 10 or between the ground and the insulation monitoring device 10.

[0079] In addition, if a disconnection occurs, the control unit 100 can send a notification message to a pre-set server or the administrator's terminal via the communication unit 106 to notify the insulation monitoring device 10 of the abnormal connection status.

[0080] On the other hand, in the Figure 1The diagram shows an example where the system's transmission line 170 is single-phase, but the transmission line 170 can of course also be multi-phase. As an example, the transmission line 170 can be formed by three phases: R, S, and T. In this case, the coupling resistor 180 can be composed of resistors formed in the multi-phase transmission line; for example, in the case of three phases, it can be composed of resistors formed on the R line, S line, and T line respectively.

[0081] The following refers to the following: Figure 2a and Figure 2b The explanation is in the Figure 1 The insulation monitoring device 10 of the present invention described herein confirms whether the transmission line 170 or the ground is disconnected based on the received signal voltage Um.

[0082] Figure 2a This is a flowchart illustrating the operation process of the insulation monitoring device 10 of such an embodiment of the present invention confirming the connection status with the transmission line 170 or the ground. Furthermore, Figure 2b A graph showing an example of the change in received signal voltage detected by the insulation monitoring device 10 according to an embodiment of the present invention.

[0083] First, refer to Figure 2a The control unit 100 of the insulation monitoring device 10 in this embodiment of the invention can generate a measurement signal having a preset positive or negative voltage. Furthermore, the generated measurement signal can be output. Thus, the measurement signal output from the signal generation unit 110 can be applied to the grounded earth through the protective conductor 120 (S200).

[0084] In step S200, when the measurement signal is applied to the ground, the control unit 100 can detect the voltage detected from the insulating circuit formed by the ground and the transmission line 170, that is, the voltage Um of the received signal received from the insulating circuit in response to the measurement signal (S202).

[0085] As described above, when the insulation monitoring device 10 is correctly connected to the transmission line 170 and the ground, a system capacitor 150 based on the system capacitance between the transmission line 170 and the ground can be formed. Therefore, transient voltages based on the charging and discharging of the system capacitor 150 can be generated. Furthermore, the control unit 100 can detect the normal state voltage (S204) from the received signal voltage Um detected after the voltage charged in the system capacitor 150 has been completely discharged.

[0086] Therefore, the control unit 100 can determine a sampling interval based on the time constant preset in step S204, and calculate the average received signal voltage of the determined sampling interval. Furthermore, a new sampling interval can be determined, and the average received signal voltage of the newly determined sampling interval can be calculated. Moreover, if the difference between the average received signal voltage calculated in the previous sampling interval and the average received signal voltage calculated in the newly determined sampling interval is below a preset error, the average received signal voltage calculated in the newly determined sampling interval can be determined as the normal state voltage.

[0087] However, if the difference between the average received signal voltages exceeds the preset error, the control unit 100 can re-execute the process of redetermining the sampling interval, calculating the average voltage within the newly determined sampling interval, and calculating the average received signal voltage calculated in the previous sampling interval and the average received signal voltage of the newly determined sampling interval. Therefore, step S204 can be repeatedly executed until the difference between the average received signal voltage of the currently set sampling interval and the average received signal voltage of the previous sampling interval is below the preset error.

[0088] On the other hand, if a normal state voltage is detected in step S204, the control unit 100 can confirm whether a transient voltage caused by the charging of the system capacitor is detected within a preset time (S206).

[0089] In this case, the control unit 100 can set the preset time when the normal state voltage is detected. That is, the control unit 100 can count the time elapsed after the normal state voltage is detected. Furthermore, it can confirm whether a transient voltage is detected within the preset time. Additionally, if a transient voltage occurs within the preset time, the time count can be initialized.

[0090] on the other hand, Figure 2b This is an example illustrating the received signal voltage Um of the transient voltage generated when the signal generation unit 110 generates a measurement signal with a preset positive voltage for a specified time and then regenerates a measurement signal with a preset negative voltage for a specified time after a specified time.

[0091] like Figure 2bAs shown, the normal state voltage is the voltage after the system capacitor 150 has been fully discharged from its charging state (voltage in interval 210 or interval 220), and can have a specified positive voltage +Vm or negative voltage -Vm. Conversely, the transient voltage is a voltage larger than the normal state voltage, and can be the voltage in interval 211 or interval 212 having a voltage value greater than the normal state voltage (voltage in interval 210 or interval 220, +Vm or -Vm) by a predetermined value of Vd or more.

[0092] Therefore, in step S206, if a normal state voltage is detected, the control unit 100 can confirm whether a voltage larger than the normal state voltage detected in step S204 (e.g., Vd) is detected within a preset time. Furthermore, if a voltage larger than the normal state voltage +Vm or -Vm (e.g., Vd) is detected within the preset time, the control unit 100 can determine that the received signal voltage includes a transient voltage. Furthermore, it can be determined that the insulation monitoring device 10 is correctly connected to the transmission line 170 and ground, forming a closed insulation circuit. Thus, the control unit 100 can again perform step S200 and repeat the process from steps S200 to S206.

[0093] On the other hand, the transient voltage can be generated when the voltage of the measured signal changes, for example, when the voltage changes based on a square wave pulse pattern, or as... Figure 2b As shown, this occurs when the polarity of the measurement signal changes. Therefore, the preset time can be determined to be a time longer than the time it takes for the voltage of the measurement signal to change once, that is, a time longer than the time of one cycle in the case of generating a square wave signal with only positive or negative voltage signals, or the voltage crossing time (i.e., half a cycle) in the case of a square wave signal in which positive and negative voltages cross at a specified time interval.

[0094] That is, the preset time can be determined based on the shape and pulse period of the measurement signal generated in the signal generation unit 110.

[0095] Conversely, if the confirmation result of step S206 is that no voltage greater than the preset value above the normal state voltage is detected within the preset time, the control unit 100 can determine that at least one of the following is a disconnection: between the transmission line 170 and the insulation monitoring device 10, and between the ground and the insulation monitoring device 10. Therefore, the control unit 100 can control the communication unit 106 to send a notification message to a preset server or terminal, notifying the insulation monitoring device of an abnormal connection status (S208).

[0096] On the other hand, the above Figure 2aThe process can be performed periodically with a preset time. In this case, as described above, the preset time can be determined based on the shape and pulse period of the measurement signal generated in the signal generation unit 110. For example, the preset time can be the time corresponding to one cycle of the measurement signal. In this case, the control unit 100 can repeat the process each time one cycle of the measurement signal ends. Figure 2a The process involves detecting transient voltages from the received signal voltage Um. Furthermore, notification information can be sent based on the transient voltage detection results to inform the insulation monitoring device 10 of its connection status.

[0097] On the other hand, the Figure 2b It is assumed that the signal generation unit 110 generates measurement signals with a preset magnitude of positive or negative voltage at predetermined time intervals. However, the signal generation unit 110 may generate a square wave signal with only positive voltage as the measurement signal, or it may generate a square wave signal with only negative voltage as the measurement signal. In this case, the signal detection unit 130 may continuously detect only the intervals with positive voltage and not the intervals with negative voltage (when a square wave signal with positive voltage is applied as the measurement signal), or it may continuously detect only the intervals with negative voltage and not the intervals with positive voltage (when a square wave signal with negative voltage is applied as the measurement signal).

[0098] On the other hand, the process of detecting the normal state received signal voltage in step S204 may be part of the process of the insulation resistance calculation unit 108 calculating the insulation resistance 140.

[0099] According to the above explanation, in the event of a transient voltage, in order to prevent the insulation resistance 140 from being incorrectly calculated due to the transient voltage, the insulation resistance calculation unit 108 can calculate the insulation resistance 140 from the stable received signal voltage, that is, the received signal voltage under normal conditions. Therefore, the control unit 100 can retain the calculation of the insulation resistance 140 until the received signal voltage under normal conditions is detected.

[0100] In this case, the process of calculating the normal state voltage in order to calculate the magnitude of the insulation resistance 140 can correspond to step S204. Therefore, when the normal state voltage is detected in step S204, the control unit 100 can proceed to step S206 while controlling the insulation resistance calculation unit 108 to calculate the insulation resistance 140 based on the detected normal state voltage, and detect whether there is a transient voltage caused by the system capacitor 150 within a preset time.

[0101] On the other hand, the above description used the example of detecting the normal state voltage based on the received signal voltage Um, but the normal state voltage used to detect the transient voltage can of course also be pre-stored in the memory 104. In this case, step S204 can be the step of reading the normal state voltage stored in the memory 104. In this case, the normal state voltage stored in the memory 104 and the normal state voltage detected by the insulation resistance calculation unit 108 to calculate the magnitude of the insulation resistance 140 can be different from each other.

[0102] on the other hand, Figure 3 This is a flowchart showing in more detail the operation process of step S206 of FIG2 in the insulation monitoring device 10 of an embodiment of the present invention, which determines whether a transient voltage is included from the received signal voltage Um.

[0103] Reference Figure 3 The control unit 100 of the insulation monitoring device 10 in this embodiment of the invention can calculate the difference between the currently detected received signal voltage and the normal state voltage detected in step S204, so as to detect whether the detected received signal voltage is a transient voltage (S300). In addition, it can determine whether the calculated voltage difference is greater than or equal to a preset voltage value (e.g., Vd) (S302).

[0104] If the determination result of step S302 is that the calculated voltage difference is less than a preset voltage value, the control unit 100 can confirm whether the preset time has elapsed (S308). Furthermore, if the preset time has not elapsed, step S300 can be performed again to calculate the difference between the currently detected received signal voltage and the normal state voltage, and step S302 can be performed to compare the calculated voltage difference with the preset voltage value.

[0105] Furthermore, based on the judgment result of step S302, step S308 can be performed again to determine whether a preset time has elapsed. If the confirmation result of step S308 indicates that the preset time has elapsed, the control unit 100 can determine that no transient voltage caused by the charging and discharging of the system capacitor 150 has been generated. Therefore, the control unit 100 can proceed from step S206 in FIG2 to step S208, sending a notification message to inform the insulation monitoring device 10 of an abnormal connection status.

[0106] On the other hand, in the event of insulation failure due to grounding or other reasons, as the insulation resistance 140 decreases, the received signal voltage Um can have a large value. In such a case, it can be determined that the large received signal voltage Um due to grounding generates a transient voltage.

[0107] To prevent this situation, if the calculated voltage difference is greater than a preset amount than the normal voltage, the control unit 100 can confirm whether the received signal voltage Um has undergone a substantial change. Furthermore, it can determine whether a transient voltage has occurred based on whether the received signal voltage Um has changed. This is because, in an unstable state, i.e., when the system capacitor 150 is not fully discharged, as described above... Figure 2b As shown, the value of the received signal voltage Um gradually decreases as the system capacitor 150 discharges. Therefore, if the judgment result of step S302 is that the calculated voltage difference is greater than or equal to a preset value, the control unit 100 can confirm whether the detected value of the received signal voltage Um has changed within a specified time (S304).

[0108] Furthermore, if the confirmation result of step S304 is that the magnitude of the received signal voltage Um changes by a predetermined amount or more within a predetermined time, the control unit 100 can determine that a transient voltage has occurred (S306). The predetermined amount is used to confirm whether the received signal voltage has undergone a substantial change. Therefore, even if the received signal voltage changes, but does not change by more than the predetermined amount, the control unit 100 can ignore the change in the received signal voltage as an effect of noise, etc.

[0109] Furthermore, if the confirmation result of step S306 is that a transient voltage has been generated, the control unit 100 can re-enter step S200 from step S206 in FIG2 and repeatedly execute the process from step S200 to step S206.

[0110] Conversely, if the confirmation result of step S304 is that the magnitude of the received signal voltage Um does not change by more than a predetermined amount within a specified time, i.e., a received signal voltage greater than a preset amount than the normal state voltage is continuously detected, then the control unit 100 can determine that a grounding has occurred due to insulation failure between the transmission line 170 and the ground. Therefore, the control unit 100 can control the communication unit 106 to send notification information to a preset server or administrator's terminal (S312). In this case, the notification information sent in step S312 may include information notifying the insulation monitoring device 10 of an abnormal insulation status.

[0111] On the other hand, with the above Figure 1Due to differences in structure, the insulation monitoring device in this embodiment of the invention may include a switch (hereinafter referred to as a circuit switch) capable of opening and closing an insulation circuit formed by the protective conductor 120, signal generation unit 110, signal detection unit 130, coupling resistor 180, transmission line 170, insulation resistor 140, and ground connection. Furthermore, when installing or resetting the insulation monitoring device, the connection status between the insulation monitoring device and the transmission line 170, and between the insulation monitoring device and the ground, can be confirmed in conjunction with the on / off state of the circuit switch 410.

[0112] Figure 4 This is a block diagram illustrating the configuration of the insulation monitoring device 40 of the present invention, as described above, including a circuit switch 410 for controlling and switching the insulation circuit connected to ground, as well as the transmission line 170, the insulation resistance 140, and the insulation circuit. Furthermore, Figure 5 It is shown that Figure 4 The flowchart shown illustrates the process by which the insulation monitoring device 40 confirms the connection status between the insulation monitoring device 40 and the transmission line 170, as well as the insulation monitoring device 40 and the ground, and calculates the insulation resistance based on the on / off state of the circuit switch 410.

[0113] First, refer to Figure 4 The circuit switch 410 can be configured on the connection transmission line 170, the insulation resistance 140, and the ground insulation circuit within the insulation monitoring device 40. More preferably, the circuit switch 410 can be configured between the coupling resistor 180 and the detection resistor Rm. Furthermore, it can be turned on or off according to the control of the control unit 400.

[0114] Here, the "on" state of the circuit switch 410 can refer to the state where the two ends of the circuit switch 410 are connected to each other. Therefore, when the circuit switch 410 is on, the coupling resistor 180 and the detection resistor Rm can be connected. Therefore, the insulating circuit formed by the protective conductor 120, the signal generation unit 110, the signal detection unit 130, the coupling resistor 180, the transmission line 170, the insulation resistor 140, and the ground connection can be closed.

[0115] Conversely, the "off" state of the circuit switch 410 can refer to a state where the two ends of the circuit switch 410 are not connected to each other. Therefore, when the circuit switch 410 is off, the coupling resistor 180 and the detection resistor Rm can be electrically disconnected. Thus, the insulating circuit formed by the protective conductor 120, the signal generation unit 110, the signal detection unit 130, the coupling resistor 180, the transmission line 170, the insulation resistor 140, and the ground connection can be opened. In this case, the insulation monitoring device 10 can be detached from the system.

[0116] On the other hand, when the insulation monitoring device 40 meets the preset conditions, the control unit 400 can turn the circuit switch 410 on or off. For example, the control unit 400 can reapply power to the insulation monitoring device 40 when the power is off, or turn off the circuit switch 410 when the insulation monitoring device 40 is reset.

[0117] Figure 5 This diagram illustrates the process by which the insulation monitoring device 40 of this embodiment calculates the magnitude of the insulation resistance 140 after confirming whether the insulation monitoring device 40 is correctly connected to the transmission line 170 and the ground, based on the operating state of the circuit switch 410 when the insulation monitoring device 40 is started to operate due to power re-application or reset as described above.

[0118] Reference Figure 5 In this embodiment of the invention, the control unit 400 of the insulation monitoring device 40 can control the signal generation unit 110 to generate and output a measurement signal when the drive starts (S500).

[0119] On the other hand, considering the voltage across the circuit switch 410, the detected received signal voltage Um can be calculated according to the following formula 1.

[0120] [Formula 1]

[0121]

[0122] Where Um is the received signal voltage, V offset It is the bias voltage, A v Rm is the receiver gain, Up is the measured signal voltage, Rm is the detection resistor, Rc is the coupling resistor, Re is the insulation resistance, and Rs is the resistance between the two ends of the circuit switch.

[0123] On the other hand, during the S500 step, the circuit switch 410 can remain in the ON state. For example, the default state of the circuit switch 410 can be the ON state, so the ON state can be maintained even without the control of the control unit 400.

[0124] Furthermore, the control unit 400 can disconnect the circuit switch 410 (S502). This breaks the electrical connection between the coupling resistor 180 and the detection resistor Rm, thus opening the insulating circuit formed by the transmission line 170, the insulation resistor 140, and the ground connection. In other words, the insulation monitoring device 40 can be separated from the system.

[0125] As described above, when the circuit switch 410 is open, the control unit 400 can detect the received signal voltage Um through the signal detection unit 130 (S504). In this case, if the two ends of the circuit switch 410 are not connected, the resistance Rs across the circuit switch 410 can be close to infinity. Therefore, if the received signal voltage Um is calculated according to Formula 1, when the circuit switch 410 is open, the received signal voltage Um can be calculated by only the bias voltage V as shown in Formula 2 below. offset .

[0126] Here, the bias voltage is the voltage applied by the circuit itself to compensate for the situation where there is output even when the input signal is zero. The bias voltage may be a preset voltage applied to the signal detection unit 130.

[0127] [Formula 2]

[0128] U m =V offset [if switch is off]

[0129] If a received signal voltage Um is detected while the circuit switch 410 is open, the control unit 400 can turn the circuit switch 410 back on (S506). Alternatively, the received signal voltage Um can be detected again while the circuit switch 410 is on (S508).

[0130] On the other hand, when the circuit switch 410 is closed, the coupling resistor 180 and the detection resistor Rm can be connected. Therefore, the insulating circuit formed by the transmission line 170, the insulation resistor 140, and the ground connection can be closed again. In this case, the resistance across the circuit switch 410 can approach zero. Therefore, when the circuit switch 410 is closed, the received signal voltage Um can be calculated according to the following formula 3.

[0131] [Formula 3]

[0132]

[0133] Furthermore, when the received signal voltage Um is detected while the circuit switch 410 is on, the control unit 400 can detect whether the change in the detected received signal voltage Um includes transient voltage caused by the charging and discharging of the system capacitor (S510).

[0134] On the other hand, step S510 can be derived from the method described in the original text. Figure 3 The process shown is the detection of transient voltages by detecting the received signal voltage Um. In this case, in the... Figure 3 In step S510, if a voltage greater than a predetermined value than the normal state voltage is detected, it is determined that the received signal voltage Um contains a transient voltage. In this case, the control unit 400 can convert the received signal voltage Um calculated in step S504, i.e., the bias voltage V detected when the circuit switch 410 is open, into the received signal voltage Um. offset The voltage is considered to be in the normal state, and the presence or absence of transient voltage can be detected based on the bias voltage.

[0135] In this case, if the insulation monitoring device 40 is correctly connected to the transmission line 170 and the ground, then as described... Figure 2b As shown, the received signal voltage Um can be significantly increased (transient voltage) within a specified time 211 or 221 by the system capacitance located between the transmission line 170 and ground. Furthermore, it can gradually decrease over time. Additionally, when the system capacitor 150 is fully discharged, a voltage close to DC can be detected, such as... Figure 2b The stable time intervals are shown as 210 or 220.

[0136] Therefore, the control unit 400 can detect the presence of transient voltage based on the magnitude change of the received signal voltage Um, and can determine that the insulation monitoring device 40 is correctly connected to the transmission line 170 and the ground.

[0137] As described above, if it is determined that the insulation monitoring device 40 is correctly connected to the transmission line 170 and the ground, the control unit 400 can detect the received signal voltage Um and detect the normal state voltage from the detected received signal voltage Um (S514). Furthermore, the insulation resistance 140 can be calculated based on the detected normal state voltage (S516). Furthermore, steps S514 and S516 can be repeatedly executed to continuously monitor the insulation state of the transmission line 170.

[0138] Conversely, if the insulation monitoring device 40 is not properly connected to the transmission line 170 and ground (e.g., in a disconnected state, or isolated from the system), a system capacitor 150 based on the system capacitance located between the transmission line 170 and ground will not be formed. Therefore, no charging or discharging of the system capacitor 150 will occur, thus allowing the bias voltage V to be continuously monitored. offset The state of the transient voltage may be undetectable.

[0139] Therefore, the control unit 400 can determine that the insulation monitoring device 40 is not properly connected to the transmission line 170 and the ground, and can control the communication unit 106 to send a notification message to the preset server or the administrator's terminal to notify that the connection status of the insulation monitoring device 40 is abnormal.

[0140] On the other hand, the above description illustrates an example where the circuit switch 410 is turned off and on again when the insulation monitoring device 40 starts to drive due to power reapplication or reset. However, the circuit switch 410 can also be turned off and on upon receiving a request from the administrator.

[0141] In this case, since the insulation monitoring device 40 is continuously driven, it can be in a state where the signal generation unit 110 generates and applies a measurement signal. Therefore, if the circuit switch 410 is turned on and off according to the manager's request during the operation of the insulation monitoring device 40, the aforementioned... Figure 5 The step of the control signal generation unit 110 in step S500.

[0142] On the other hand, in the above Figure 5 The example described is that a circuit switch 410 is provided between the coupling resistor 180, which is a combined resistor connected to each transmission line L1, L2, and the detection resistor Rm. However, the circuit switch 410 can of course also be provided on each transmission line L1, L2 respectively.

[0143] Figure 6 This is a block diagram illustrating the structure of an insulation monitoring device 40 according to an embodiment of the present invention, which is connected to a plurality of transmission lines through a plurality of circuit switching switches.

[0144] Reference Figure 6 The first coupling resistor 181, connected to the first transmission line L1, can be connected in series with the first switch 411 among the plurality of switches constituting the circuit switching switch 410. Similarly, the second coupling resistor 182, connected to the second transmission line L2, can be connected in series with the second switch 412 among the plurality of switches constituting the circuit switching switch 410. Furthermore, the control unit 400 can independently control the first switch 411 and the second switch 412.

[0145] As an example, the control unit 400 can simultaneously turn the first switch 411 and the second switch 412 on or off, or it can turn on any one of the first switch 411 and the second switch 412 and turn off the other switch. In this case, when both the first switch 411 and the second switch 412 are on or off, it can be used in conjunction with... Figure 4 and Figure 5 The circuit described herein has the same on / off state as the switch 410.

[0146] Additionally, the control unit 400 can control the first switch 411 and the second switch 412 respectively to confirm the connection status of each transmission line L1, L2 and the insulation monitoring device 40. For this purpose, the control unit 400 can control the first switch 411 and the second switch 412 respectively to perform operations as described above. Figure 5 A process similar to that described in the document is used to confirm the connection status of the insulation monitoring device 40.

[0147] As an example, the control unit 400 can detect the received signal voltage via the signal detection unit 130 when both the first switch 411 and the second switch 412 are open. In this case, since both the first switch 411 and the second switch 412 are open, the electrical connection between the first transmission line L1, the second transmission line L2, and the insulation monitoring device 40 can be broken. Therefore, the bias voltage can be detected in the signal detection unit 130.

[0148] In this state, the control unit 400 can initially only turn on the first switch 411. Under these circumstances, the second switch 412 can remain in the off state. Thus, a first insulation circuit can be formed, in which the first transmission line L1, the first insulation resistance 141, and the ground are connected to the signal generation unit 110 and the protective conductor 120 through the first coupling resistor 181 and the detection resistor Rm.

[0149] Therefore, the control unit 400 can detect the received signal voltage through the signal detection unit 130, and can detect whether the detected change in the received signal voltage includes transient voltage. In this case, with the aforementioned Figure 5 Similarly, the control unit 400 can detect transient voltage based on the received signal voltage, i.e., the bias voltage, detected when both the first switch 411 and the second switch 412 are open.

[0150] As an example, the control unit 400 can detect the transient voltage based on whether there is a voltage that is larger than a preset value than the bias voltage. Furthermore, if a transient voltage is detected, it can be determined that the insulation monitoring device 40 is correctly connected to the first transmission line L1.

[0151] On the other hand, if the connection between the insulation monitoring device 40 and the first transmission line L1 is confirmed, the control unit 400 can disconnect the first switch 411 and connect the second switch 412. Then, the first insulation circuit, which connects the first transmission line L1, the first insulation resistor 141, and the ground to the signal generation unit 110 and the protective conductor 120 via the first coupling resistor 181 and the detection resistor Rm, can be opened, and a second insulation circuit, which connects the second transmission line L2, the second insulation resistor 142, and the ground to the signal generation unit 110 and the protective conductor 120 via the second coupling resistor 182 and the detection resistor Rm, can be formed.

[0152] Therefore, the control unit 400 can detect the received signal voltage through the signal detection unit 130, and can detect whether the detected change in the received signal voltage includes transient voltage. In this case, with the aforementioned Figure 5 Similarly, the control unit 400 can detect transient voltages based on the bias voltage.

[0153] As an example, the control unit 400 can detect the transient voltage based on whether there is a voltage that is larger than a preset value than the bias voltage. Furthermore, if a transient voltage is detected, it can be determined that the insulation monitoring device 40 is correctly connected to the second transmission line L2.

[0154] As described above, the insulation monitoring device 40 of this embodiment can determine the connection status between the first transmission line L1 and the second transmission line L2 and the insulation monitoring device 40 based on the operating status of the first switch 411 and the second switch 412. Furthermore, if the confirmation result indicates that the first transmission line L1 and the second transmission line L2 are correctly connected to the insulation monitoring device 40, the control unit 400 can turn on the first switch 411 and the second switch 412. Additionally, the insulation resistance 140 can be calculated based on the voltage detected by the signal detection unit 130, and the insulation status between the transmission line 170 and the ground can be monitored using the calculated insulation resistance 140.

[0155] Conversely, if the result of confirming the connection status between the first transmission line L1 and the second transmission line L2 and the insulation monitoring device 40 is that at least one of the first transmission line L1 and the second transmission line L2 is disconnected from the insulation monitoring device 40, the control unit 400 can send a notification message to a preset server or the administrator's terminal to notify that the connection status of the insulation monitoring device 40 is abnormal.

[0156] In this case, the notification information may include information about the transmission line where the electrical connection to the insulation monitoring device 40 has been broken. As an example, the notification information may include information about either the first transmission line L1 or the second transmission line L2 where the connection to the insulation monitoring device 40 has been broken.

[0157] On the other hand, the insulation monitoring device of this embodiment can be connected to the casing of the load (e.g., the casing or panel of a distribution panel) via ground. For this purpose, the insulation monitoring device 70 can have a terminal (hereinafter, casing terminal KE) connected to the casing of the load.

[0158] Figure 7 This is a conceptual diagram illustrating an example of an insulation monitoring device 70 connected to the housing 71 of a load according to an embodiment of the present invention.

[0159] Reference Figure 7 The insulation monitoring device 70 of this embodiment of the invention may have a protective conductor PE, 120 and a housing terminal KE, 820. Furthermore, the protective conductor PE, 120 may be grounded to earth 710, and the housing terminal KE, 820 may be connected to the load, i.e., the housing 71 of the distribution panel. Additionally, the housing 71 of the distribution panel may be grounded to earth 710.

[0160] Therefore, as Figure 7 As shown, the protective conductors PE and 120 and the distribution panel housing 71 can be connected to each other via ground 710. Furthermore, the distribution panel housing 71 can be connected to the insulation monitoring device 70 via housing terminals KE and 820. Therefore, as... Figure 7 As shown, a circuit (hereinafter, housing grounding circuit 720) can be formed connecting the protective conductors PE, 120, ground 710, distribution panel housing 71, and housing terminals KE, 820 to each other. Therefore, when the measurement signal generated in the signal generation unit 110 is applied to the ground 710 through the protective conductors PE, 120, the measurement signal can be transmitted to the insulation monitoring device 70 via the housing grounding circuit 720 through the housing terminals KE, 820.

[0161] On the other hand, the insulation monitoring device 70 of this embodiment can be based on, for example... Figure 7 The enclosure grounding circuit 720, as shown, is used to confirm the connection status of the distribution panel enclosure 71 and the insulation monitoring device 70, as well as the grounding status of the distribution panel enclosure 71.

[0162] Figure 8 This is a block diagram illustrating the configuration of an insulation monitoring device 70 according to an embodiment of the present invention, which is capable of confirming the connection of the housing 71 of the load and the grounding state of the housing 71 of the load by means of a housing grounding circuit 720 connected via housing terminals KE, 820 as described above.

[0163] Reference Figure 8 The insulation monitoring device 70 of this embodiment of the invention may have housing terminals KE and 820. In addition, the housing terminal 820 may be connected to a housing grounding switch 710 connected to the insulation resistance Rm, and the housing grounding switch 710 may be controlled to be turned on and off by the control unit 400.

[0164] Here, if the enclosure grounding switch 710 is turned on, its two ends can be connected to each other. Therefore, the sensing resistor Rm can be connected to the enclosure terminal 820, and can be connected to the enclosure grounding circuit 720 through the enclosure terminal 820. That is, it can be connected to a grounded load, such as the distribution panel enclosure 71, via the earth, so that the signal generation unit 110, the enclosure grounding circuit 720 (protective conductor 120, earth 710, load (e.g., distribution panel) enclosure 71, enclosure terminal 820), and the sensing resistor Rm can be connected to form a closed enclosure circuit. Furthermore, the default state of the enclosure grounding switch 710 can be the turned-on state.

[0165] Conversely, if the housing grounding switch 710 is opened, the electrical connection between the two ends of the housing grounding switch 710 can be severed. Therefore, the connection between the sensing resistor Rm and the housing terminal 820 can be broken. Thus, the housing circuit can be opened.

[0166] In having Figure 8 In the configuration shown, the insulation monitoring device 70 of this embodiment of the invention can control the housing grounding switch 710 and determine the connection status between the load housing and the insulation monitoring device 70 based on the voltage detected by the signal detection unit 130 when the housing grounding switch 710 is open or closed.

[0167] In this case, if the transmission line 170 and the detection resistor Rm are connected, the voltage received through the insulation circuit including the insulation resistor 140 and the voltage input through the housing terminal 820 can be combined. Therefore, it may be impossible to accurately measure the connection status between the load housing and the insulation monitoring device 70. Thus, the control unit 400 can confirm the connection status between the housing and the insulation monitoring device 70 even when there is no connection between the transmission line 170 and the insulation monitoring device 70.

[0168] Therefore, the control unit 400 can be in the... Figure 5In order to confirm the connection between the transmission line 170 and the insulation monitoring device 70, when the insulation circuit between the transmission line 170 and the insulation monitoring device 70 is open, that is, when the circuit opening switch 410 is disconnected, the housing grounding switch 710 is controlled to further confirm the connection status of the insulation monitoring device 70, the housing of the load and the insulation monitoring device 70.

[0169] Figure 9 It is shown as described above in the Figure 5 A flowchart illustrating the operation process of the insulation monitoring device 70 in this embodiment of the invention, further confirming the connection status between the insulation monitoring device 70 and the load housing when the circuit switch 410 is open.

[0170] Reference Figure 9 If in the Figure 5 If the circuit switch 410 is disconnected in step S502, the control unit 400 of the insulation monitoring device 70 of this embodiment of the invention can disconnect the housing grounding switch 710 (S902).

[0171] On the other hand, if the housing grounding switch 710 is open, the control unit 400 can detect the received signal voltage Um through the signal detection unit 130 (S902). In this case, since the circuit opening switch 410 is in the open state, the insulation circuit including the transmission line 170, the ground, and the insulation resistor 140 can be opened. In addition, since the housing grounding switch 710 is in the open state, the housing circuit formed by the signal generation unit 110, the housing grounding circuit 720 (protective conductor 120, ground 710, load (distribution panel) housing 71, housing terminal 820), and the detection resistor Rm can also be opened. Therefore, as shown in Formula 2, the signal detection unit 130 can detect only the bias voltage.

[0172] If a received signal voltage is detected in step S902 while the housing grounding switch 710 is open, the control unit 400 can turn on only the housing grounding switch 710 while keeping the circuit open switch 410 open (S904). Thus, although the insulation circuit remains open, the housing circuit can be closed. Therefore, the measurement signal applied to ground via the protective conductor 120 can be applied to the load housing via the ground and can be reapplied to the insulation monitoring device 70 via the housing terminal 820.

[0173] On the other hand, if the housing grounding switch 710 is turned on, the control unit 400 can re-detect the received signal voltage through the signal detection unit 130 (S906). Thus, the signal detection unit 130 can measure the voltage of the received signal based on the measurement signal applied to the housing circuit from the housing circuit. Furthermore, the received signal voltage detected in step S906 (the received signal voltage detected when the housing grounding switch 710 is turned on, hereinafter referred to as the received signal voltage) and the received signal voltage detected in step S902 (the received signal voltage detected when the housing grounding switch 710 is turned off, hereinafter referred to as the bias voltage) can be compared (S908).

[0174] In this case, if the load's casing is correctly grounded, a measurement signal can be applied from the ground to the casing grounding circuit 720. Furthermore, the signal applied to the casing grounding circuit 720 can be received through the casing terminal 820 connected to the casing grounding circuit 720. Thus, the received signal voltage detected by the signal detection unit 130 can detect a voltage different from the bias voltage. For example, when the distance between the grounding position of the load's casing and the grounding position of the insulation monitoring device 70 is sufficiently close, the signal detection unit 130 can detect a received signal voltage of similar magnitude to the measurement signal voltage.

[0175] Conversely, if the load's casing is not properly grounded—that is, there is no connection between the load's casing and ground, or between the casing terminal 820 and the load's casing—the casing circuit can be open even when the casing grounding switch 710 is on. Therefore, the received signal voltage Um detected by the signal detection unit 130 can be a bias voltage.

[0176] Therefore, in step S908, the control unit 400 can compare the detected received signal voltage with the detected bias voltage. Furthermore, if the difference between the received signal voltage and the bias voltage is greater than a predetermined value, it can be determined that the connection between the insulation monitoring device 70 and the load housing is normal. Thus, the control unit 400 can restart the process. Figure 5 S504 steps and execution Figure 5 The process following step S502.

[0177] Here, the specified magnitude, which serves as a reference for comparing the received signal voltage and the bias voltage, can be used to determine whether there is a substantial difference between the received signal voltage and the bias voltage, thereby preventing misjudgment caused by noise or other factors.

[0178] On the other hand, in step S908, the control unit 400 can compare the detected received signal voltage with the detected bias voltage. Furthermore, if the comparison result shows that the difference between the received signal voltage and the bias voltage is less than the specified value, the control unit 400 can determine that there is an abnormality in the electrical connection between the load housing 71 and the insulation monitoring device 70.

[0179] In this situation, if a leakage or grounding accident occurs, electricity will flow through the load's casing, posing a risk of electric shock. Therefore, if the comparison result of step S908 indicates an abnormality in the connection between the load's casing and the insulation monitoring device 70, the control unit 400 can control the communication unit 106 to send a notification message to a pre-set server or administrator's terminal, informing them of the abnormality in the connection between the load's casing and the insulation monitoring device 70. Furthermore, the casing grounding switch 710 can be disconnected to cut off the electrical connection between the load's casing 71 and the insulation monitoring device 70.

[0180] On the other hand, the circuit open switch 410 or the housing grounding switch 710 in the embodiments of the present invention may have a dual switch structure with a master-slave structure.

[0181] Figure 10 This is an example diagram illustrating the operation of the master-slave switch when the switch in the insulation monitoring device provided in an embodiment of the present invention is configured as a master-slave switch. Hereinafter, Figure 10 For ease of explanation, the invention will be described using the circuit open switch 410 having the aforementioned dual-switch structure as an example. However, the invention is certainly not limited to this.

[0182] Typically, in a master-slave dual-structure switch, either switch, such as the slave switch, can be used to replace the master switch when the master switch malfunctions. Therefore, if the master switch 1000 is composed of a plurality of switches respectively connecting a plurality of coupling resistors 180 and signal detection units 130, the slave switch 1001 can also be composed of a plurality of switches respectively connecting a plurality of the coupling resistors 180 and signal detection units 130, just like the master switch 1000. Thus, the master switch and the slave switch can be connected in parallel.

[0183] On the other hand, a typical switch employing a master-slave dual structure, as described above, can have an activation signal applied to either the master switch or the slave switch. Furthermore, it can be configured to form a circuit using either switch to which an activation signal is applied.

[0184] However, in the case of such a typical dual-structure switch, in order to further shorten the switching time, a structure is provided in which each switch maintains the connection of the circuit regardless of its operating state. That is, even when the main switch is activated, the two ends of the slave switch can remain connected to each other, and conversely, even when the slave switch is activated, the two ends of the main switch can remain connected to each other.

[0185] However, it has a structure that, when the main switch is activated, only the main switch is activated, and the circuit is connected only along the path through the main switch; similarly, when the slave switch is activated, only the slave switch is activated, and the circuit is connected only along the path through the slave switch. Therefore, in the event of a problem with either switch, the circuit can be switched to the path through the other switch more quickly.

[0186] However, as mentioned above, when all switches remain closed regardless of whether they are active or not, the circuit connection may lead to an increase in resistance. That is, even in the inactive state, if the switch is in the connected state, the internal resistance of the insulation resistance device may increase due to the resistance of the switch itself. In this case, the value of the insulation resistance may be miscalculated due to the increased internal resistance.

[0187] Therefore, in the switch of the insulation monitoring device of this embodiment, the control unit 400 can send operation signals to the main switch 1000 and the slave switch 1001, causing the main switch 1000 and the slave switch 1001 to perform opposite actions. That is, if an on-action signal to turn on the switch is sent to either switch, an off-action signal to turn off the switch can be sent to the other switch.

[0188] Reference Figure 10 , Figure 10 The first diagram (top diagram) shows an example of sending an on / off action signal to the main switch 1000. In this case, the control unit 400 can send an off / off action signal, which is the opposite of the on / off action signal. Thus, as... Figure 10 As shown in the first figure, a disconnection signal can be sent to the slave switch 1001. Therefore, when the two ends of the main switch 1000 are connected, i.e., when the two ends of the switch are closed, the connection between the two ends of the slave switch 1001 can be disconnected, thus opening the switch. That is, when the main switch 1000 is connected to the system, the slave switch 1001 can be disconnected from the system.

[0189] On the contrary, such as Figure 10 As shown in the second figure (below), when an on / off signal is sent to the slave switch 1001, the control unit 400 can send an off / off signal, which is the opposite of the on / off signal, to the main switch 1000. Thus, as... Figure 10As shown in the second figure, a disconnection signal can be sent to the main switch 1000. Therefore, when the two ends of the slave switch 1001 are connected, i.e., when the two ends of the switch are closed, the connection between the two ends of the main switch 1000 can be disconnected, thus opening the two ends of the switch. That is, when the slave switch 1001 is connected to the system, the main switch 1000 can be disconnected from the system.

[0190] On the other hand, in the above description, the example given is that the control unit 400 sends opposite action signals to the main switch 1000 and the slave switch 1001 respectively, but the system separation function can be a function set by the switch itself.

[0191] As an example, the main switch 1000 and the slave switch 1001 can be switches that are set to the off state by default. That is, the main switch 1000 and the slave switch 1001 can be switches that are in the off state even when there is no operation signal from the control unit 400, even if the circuit is open.

[0192] In this case, the control unit 400 can apply an action signal to either the main switch 1000 or the slave switch 1001. The switch that receives the action signal can then be activated and operate in the ON state, forming a circuit through that switch. Meanwhile, the other switch, which does not receive an action signal, remains in the OFF state by default, thus maintaining its isolation from the system.

[0193] On the other hand, if the control unit 400 applies an action signal to the other switch in this state, the action signal may not be applied to either switch. Thus, either switch can be switched to the off state (default state), thereby isolating it from the system.

[0194] The control method of the insulation monitoring device of the present invention described above can be implemented by computer-readable code on a medium containing a program. Computer-readable media include all types of recording devices storing data readable by a computer system. Examples of computer-readable media include HDD (Hard Disk Drive), SSD (Solid State Disk), SDD (Silicon Disk Drive), ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage devices, etc., and also include those implemented in the form of carrier waves (e.g., Internet-based transmission). Furthermore, the computer may also include a control unit for the insulation monitoring device. Therefore, the detailed description above should not be construed as limiting in all respects, but should be understood as exemplary. The scope of the invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the invention fall within the scope of the invention.

Claims

1. An insulation monitoring device for measuring the insulation resistance between a transmission line and ground, characterized in that, include: The signal generation unit generates a measurement signal with a preset voltage and applies the measurement signal to the ground through a protective conductor connected to one end of the signal generation unit. A coupling resistor is connected to the transmission line; The signal detection unit includes a detection resistor disposed between the coupling resistor and the other end of the signal generation unit, and detects the voltage of the measurement signal distributed in the internal resistance of the insulation monitoring device formed by the coupling resistor and the detection resistor based on the voltage difference across the detection resistor; as well as The control unit detects the transient voltage caused by the charging and discharging of the system capacitor formed by the parasitic capacitance between the transmission line and the ground from the voltage detected by the signal detection unit, and confirms the connection status of the insulation monitoring device with the transmission line and the ground based on the result of detecting the transient voltage. The control unit detects the normal state voltage from the voltage detected by the signal detection unit, and detects voltages that are greater than or equal to a preset value than the detected normal state voltage as transient voltages.

2. The insulation monitoring device according to claim 1, characterized in that, The control unit detects the transient voltage from the voltage detected by the signal detection unit at a preset time interval. The preset time is determined based on at least one of the shape of the measurement signal and the period of the measurement signal.

3. The insulation monitoring device according to claim 1, characterized in that, The control unit determines a sampling period based on a preset time constant, calculates a plurality of average voltages of a plurality of voltages detected by the signal detection unit in each sampling period, and detects the normal state voltage based on the differences between the calculated plurality of average voltages.

4. The insulation monitoring device according to claim 1, characterized in that, If a voltage greater than a preset value is detected, the control unit detects whether the magnitude of the detected voltage changes by a predetermined value within a specified time, and further determines whether the transient voltage has been generated based on the change in the magnitude of the detected voltage.

5. The insulation monitoring device according to claim 1, characterized in that, It also includes a communication unit that establishes a communication connection with a pre-defined server or terminal. The control unit controls the communication unit to send a notification message to the server or terminal indicating that the connection status of the insulation monitoring device is abnormal, based on the result of detecting the transient voltage.

6. A control method for an insulation monitoring device, the insulation monitoring device measuring the insulation resistance between a transmission line and ground, the control method characterized by comprising: The steps of generating a measurement signal with a preset voltage and applying the measurement signal to the ground; The step of detecting the voltage of the measurement signal distributed in the internal resistance of the insulation monitoring device formed by the coupling resistor connected to the transmission line and the detection resistor, according to a preset detection resistor; The step of determining whether the voltage detected by the detection resistor is a normal state voltage; If the voltage detected by the detection resistor is a normal state voltage, the step is to detect whether a transient voltage has been generated within a preset time based on the voltage detected by the detection resistor. as well as The step of determining the connection status of the insulation monitoring device with the transmission line and the ground based on whether the transient voltage is generated.

7. The control method for the insulation monitoring device according to claim 6, characterized in that, The step of detecting whether the transient voltage has occurred includes: The step of calculating the voltage difference between the voltage detected by the sensing resistor and the normal state voltage; The steps involve comparing the calculated voltage difference with a preset voltage value. The step of detecting the generation of the transient voltage when the calculated voltage difference is greater than or equal to a preset value; and If the result of the comparison is that the calculated voltage difference is less than the preset voltage value, then the step of detecting that no transient voltage has been generated is performed.

8. The control method for the insulation monitoring device according to claim 6, characterized in that, The steps for determining whether the voltage is the normal state voltage include: The steps for determining the sampling period are based on a preset time constant; The steps for calculating the average voltage of a complex number of voltages detected during the sampling period; The step of calculating the difference between the average voltage and the average voltage of a plurality of voltages detected during previous sampling; The steps for comparing the calculated differences with the preset error; and Based on the comparison results, the average voltage of the plurality of voltages detected during the sampling period is determined as the normal state voltage, or the steps of determining the sampling period, calculating the average voltage, calculating the difference of the average voltage, and comparing the preset error are performed again.

9. The control method for the insulation monitoring device according to claim 6, characterized in that, The step of determining the status of the insulation monitoring device, the transmission line, and the ground connection further includes: If no transient voltage is generated within the preset time, the step of sending a notification message to a preset server or terminal indicating that the connection status of the insulation monitoring device is abnormal.

10. An insulation monitoring device for measuring the insulation resistance between a transmission line and ground, characterized in that, include: The signal generation unit generates a measurement signal with a preset voltage and applies the measurement signal to the ground through a protective conductor connected to one end of the signal generation unit. A coupling resistor is connected to the transmission line; The signal detection unit includes a detection resistor disposed between the coupling resistor and the other end of the signal generation unit, and detects the voltage of the measurement signal distributed in the internal resistance of the insulation monitoring device formed by the coupling resistor and the detection resistor based on the voltage difference across the detection resistor; The circuit switching device connects or disconnects the coupling resistor and the detection resistor. as well as The control unit controls the circuit switching on and off, and detects whether the second voltage detected by the signal detection unit when the coupling resistor and the detection resistor are connected includes a transient voltage, based on the first voltage detected by the signal detection unit when the connection between the coupling resistor and the detection resistor is cut off by the circuit switching on and off. Based on the result of detecting the transient voltage, the control unit confirms the connection status of the insulation monitoring device with the transmission line and the ground.

11. The insulation monitoring device according to claim 10, characterized in that, The first voltage is a preset bias voltage applied to the signal detection unit. If the second voltage is greater than the bias voltage by a preset voltage value, the control unit determines that the second voltage includes the transient voltage.

12. The insulation monitoring device according to claim 10, characterized in that, The transmission lines include a plurality of lines. The coupling resistor is connected to each of the plurality of the lines respectively. The circuit switching is formed by a plurality of switches formed between different coupling resistors and the detection resistors that are respectively connected to the plurality of said lines.

13. The insulation monitoring device according to claim 12, characterized in that, The control unit controls all of the plurality of switches to detect the voltage detected by the signal detection unit when the connection between each coupling resistor and the detection resistor is broken as the first voltage. The control unit selects and controls a first switch from a plurality of switches to connect a first coupling resistor connected to the first switch and the detection resistor. When the first coupling resistor and the detection resistor are connected to each other, the control unit will detect the voltage detected by the signal detection unit as the second voltage. The second voltage is used to detect whether it contains the transient voltage, based on the first voltage. The connection status of any one of the plurality of lines connected to the first coupling resistor to the insulation monitoring device is determined based on whether or not the transient voltage is present.

14. The insulation monitoring device according to claim 13, characterized in that, It also includes a communication unit that establishes a communication connection with a pre-defined server or terminal. The control unit controls the communication unit to send a notification message to the server or terminal indicating an abnormal connection status of the insulation monitoring device, based on the result of detecting the transient voltage. The notification information includes information about the connection status of any of the lines and the insulation monitoring device.

15. The insulation monitoring device according to claim 10, characterized in that, Also includes: Housing terminals, connected to the housing of the load; as well as A casing grounding switch is connected to the sensing resistor, which connects or disconnects the casing terminals and the sensing resistor.

16. The insulation monitoring device according to claim 15, characterized in that, The control unit controls the housing grounding switch to disconnect the connection between the housing terminals and the detection resistor when the connection between the coupling resistor and the detection resistor is disconnected by the circuit opening and closing switch. With the connection between the housing terminal and the detection resistor disconnected, the control unit detects the bias voltage based on the voltage detected by the signal detection unit. The control unit controls the housing grounding switch to connect the housing terminals and the detection resistor while the connection between the coupling resistor and the detection resistor is cut off by the circuit opening and closing switch. With the housing terminals and the detection resistor connected, the control unit further confirms the connection status of the load housing and the insulation monitoring device by comparing the voltage detected by the signal detection unit with the bias voltage.

17. A control method for an insulation monitoring device, the insulation monitoring device comprising a circuit switching switch between a coupling resistor connected to a transmission line and a preset detection resistor, and a signal detection unit having the detection resistor, the control method being characterized in that it includes: The steps of generating a measurement signal with a preset voltage and applying the measurement signal to the ground; The step of controlling the circuit to open and close the switch to disconnect the connection between the coupling resistor and the preset detection resistor; The step of detecting the bias voltage based on the voltage detected by the signal detection unit when the connection between the coupling resistor and the detection resistor is disconnected; The step of controlling the circuit to open and close the switch to connect the coupling resistor and the preset detection resistor; as well as The steps are as follows: detecting whether the voltage detected by the signal detection unit includes transient voltage based on the bias voltage, and determining the connection status of the insulation monitoring device with the transmission line and the ground based on whether the transient voltage is included.

18. The control method for the insulation monitoring device according to claim 17, characterized in that, The insulation monitoring device also includes: Housing terminals, for connection to the housing of the load; and A casing grounding switch is connected to the detection resistor, connecting or disconnecting the connection between the casing terminals and the detection resistor; The step of disconnecting the connection between the coupling resistor and the preset detection resistor further includes: The step of controlling the housing grounding switch to disconnect the connection between the housing terminals and the sensing resistor when the connection between the coupling resistor and the sensing resistor is disconnected; The step of detecting the bias voltage based on the voltage detected by the signal detection unit; The step of controlling the housing grounding switch to connect the housing terminals and the sensing resistor; The step of comparing the voltage detected by the signal detection unit with the bias voltage; and The step of confirming the connection status of the load housing and the insulation monitoring device based on the comparison results.

19. The control method for the insulation monitoring device according to claim 17, characterized in that, The transmission lines include a plurality of lines. The coupling resistor is connected to each of the plurality of the lines respectively. The circuit switching includes a plurality of switches formed between each other and a plurality of different coupling resistors connected to the plurality of said lines and the detection resistor. The step of connecting the coupling resistor and the preset detection resistor involves sequentially selecting one switch from a plurality of switches and controlling the selected switch to connect the coupling resistor connected to the selected switch and the detection resistor. The step of determining the connection status of the insulation monitoring device with the transmission line and the ground is as follows: when a specific coupling resistor and the detection resistor are connected to each other, the step of determining the connection status of any one of the plurality of lines connected to the specific coupling resistor and the insulation monitoring device is based on whether the voltage detected by the signal detection unit includes the transient voltage.

20. The control method for the insulation monitoring device according to claim 19, characterized in that, The step of determining the status of the insulation monitoring device, the transmission line, and the ground connection further includes: The step of sending a notification message to a pre-set server or terminal indicating that the connection status of the insulation monitoring device is abnormal, depending on whether the transient voltage is included; The notification information includes information about the connection status of each of the plurality of lines with the insulation monitoring device.

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