An insulation monitoring device, system, method, equipment, medium and auxiliary inverter system

Abstract

An insulation monitoring device, system, method, equipment, medium and auxiliary inverter system. The insulation monitoring device includes a control unit, a high-resistance isolation unit, a sampling unit and a pulse input unit. The first end of the insulation monitoring device is connected to the system to be monitored, and the second end is connected to the ground. The sampling unit includes a first sampling input end, a second sampling input end and a sampling output end. The first end of the high-resistance isolation unit is connected to the system to be monitored, and the second end is respectively connected to the first sampling input end and the second sampling input end. The first end of the pulse input unit is connected to the sampling unit, and the second end is connected to the ground. The control unit is used to control the pulse input unit to input a pulse to the sampling unit, and determine the insulation resistance value of the system to be monitored according to the signal at the sampling output end. The embodiment of the present invention can still ensure accurate measurement when part of the cable connecting the insulation monitoring device and the system to be monitored is disconnected.

Description

Technical Field

[0001] Embodiments of the present invention relate to a field, and more specifically, to an insulation monitoring device, system, method, equipment, medium and auxiliary inverter system. Background Art

[0002] Urban rail operation has very high requirements for power supply continuity, and power failure of equipment will cause serious losses. Adopting an ungrounded system can effectively reduce the frequency of power outages: when a single-point grounding fault occurs, since no short-circuit loop is formed, the system can still operate normally. However, if the fault is not eliminated in time, if a different-phase grounding fault occurs again, the system may short-circuit and power off, resulting in serious consequences.

[0003] To avoid the above problems, insulation monitoring devices are usually installed in urban rail power supply systems to continuously monitor the insulation resistance to the ground in real time through the insulation monitoring device, and notify the superior system when a single-point ground insulation fault occurs to prevent the occurrence of serious hazards.

[0004] Current insulation monitoring devices mainly adopt passive measurement methods or active measurement methods. The insulation monitoring device adopting the passive measurement method does not actively send a measurement signal into the IT power supply network (that is, a power supply system with an ungrounded neutral point). It uses the changes in electrical parameters when a single-point grounding occurs in the IT power supply network to judge whether there is a grounding fault. The insulation monitoring device adopting this measurement method can only be used in a pure DC system, and can only qualitatively but not quantitatively judge insulation problems. This type of insulation monitoring device cannot detect symmetrical grounding faults. For example, when grounding faults of similar magnitudes occur on both the + / - sides of the system at the same time, this type of insulation monitoring device cannot detect the fault.

[0005] The insulation monitoring device adopting the active measurement method can actively inject a voltage signal into the measured IT power supply system, and quantitatively calculate the magnitude of the insulation fault resistance by measuring the change in the injected voltage signal. The injected voltage signal is generally a pure DC signal, an AC square wave signal, etc. When the injected voltage signal is a pure DC signal, it can only be used in a pure AC system. When the injected voltage signal is an AC square wave signal, it can be used in an AC / DC hybrid system.

[0006] In the existing urban rail auxiliary inverter system, generally an AC / DC hybrid system, if a wire is not effectively connected during the operation of the above insulation monitoring device and the urban rail auxiliary inverter system, although the other wire is still connected to the urban rail auxiliary inverter system, that is, although an insulation fault occurs, the insulation monitoring device cannot measure the insulation fault or the measurement data is incorrect. Summary of the Invention

[0007] An embodiment of the present invention addresses the problem that the above-mentioned insulation monitoring device cannot actively detect the connection status with the monitored system, and provides an insulation monitoring device, system, method, device, medium, and auxiliary inverter system.

[0008] The technical solution for the embodiment of the present invention to solve the above technical problem is to provide an insulation monitoring device, including a control unit, a high-resistance isolation unit, a sampling unit, and a pulse input unit. The first end of the insulation monitoring device is connected to the monitored system, and the second end of the insulation monitoring device is connected to the ground; the control unit is respectively connected to the sampling unit and the pulse input unit;

[0009] The sampling unit includes a first sampling input terminal, a second sampling input terminal, and a sampling output terminal;

[0010] The first end of the high-resistance isolation unit is connected to the monitored system through a high-voltage input terminal, and the first sampling input terminal and the second sampling input terminal are respectively connected to the second end of the high-resistance isolation unit;

[0011] The first end of the pulse input unit is connected to the sampling unit, and the second end of the pulse input unit is connected to the ground;

[0012] The control unit is configured to control the pulse input unit to input a pulse to the sampling unit, and determine the insulation resistance value of the monitored system according to the signal at the sampling output terminal.

[0013] Preferably, the high-voltage input terminal includes a first high-voltage terminal and a second high-voltage terminal, and the high-resistance isolation unit includes a voltage-dividing unit connected between the first sampling input terminal and the second sampling input terminal.

[0014] Preferably, the high-resistance isolation unit includes a first resistor and a second resistor. The first end of the first resistor is connected to the first high-voltage terminal, the second end of the first resistor is connected to the first sampling input terminal, the first end of the second resistor is connected to the second high-voltage terminal, and the second end of the second resistor is connected to the second sampling input terminal.

[0015] Preferably, the resistance values of the first resistor and the second resistor are equal.

[0016] Preferably, the voltage-dividing unit includes a third resistor, one end of the third resistor is connected to the second end of the first resistor, and the other end is connected to the second end of the second resistor.

[0017] Preferably, it further includes a disconnection detection signal source input unit, the disconnection detection signal source input unit is connected to the second end of the high-resistance isolation unit, and the disconnection detection signal source input unit is also connected to the control unit;

[0018] When the pulse of the pulse input unit is turned on, the control unit controls the signal source of the disconnection detection signal source input unit to be turned off, acquires the voltage signal at the sampling output terminal, and determines the insulation resistance value of the monitored system according to the voltage signal at the sampling output terminal;

[0019] When the pulse of the pulse input unit is turned off, the control unit controls the signal source of the disconnection detection signal source input unit to be turned on, acquires the voltage at the first sampling input terminal and / or the second sampling input terminal, and determines whether the high-voltage input terminal is disconnected according to the voltage at the first sampling input terminal and / or the second sampling input terminal.

[0020] Preferably, the disconnection detection signal source input unit is connected to the first sampling input terminal; when the pulse of the pulse input unit is turned off, the control unit controls the signal source of the disconnection detection signal source input unit to be turned on, acquires the voltage signal at the second sampling input terminal, and determines whether the high-voltage input terminal is disconnected according to the voltage signal at the second sampling input terminal; or,

[0021] The disconnection detection signal source input unit is connected to the second sampling input terminal; when the pulse of the pulse input unit is turned off, the control unit controls the signal source of the disconnection detection signal source input unit to be turned on, acquires the voltage signal at the first sampling input terminal, and determines whether the high-voltage input terminal is disconnected according to the voltage signal at the first sampling input terminal.

[0022] Preferably, the disconnection detection signal source input unit includes a signal source input terminal and a fourth resistor, the signal source input terminal is connected to the fourth resistor, and the fourth resistor is connected to the first sampling input terminal or the second sampling input terminal.

[0023] Preferably, the control unit is further configured to determine the voltage at the first sampling input terminal or the second sampling input terminal according to the resistance values of the first resistor, the second resistor, the third resistor, the fourth resistor, and the input voltage of the disconnection detection signal source input unit.

[0024] Preferably, a switching unit is connected between the signal source input terminal and the fourth resistor, and the control unit controls the on / off of the switching unit.

[0025] Preferably, the sampling unit further includes a fifth resistor, a sixth resistor, and a filtering unit. The first end of the fifth resistor is connected to the first sampling input terminal, the second end of the fifth resistor is connected to the first end of the pulse input unit, the first end of the sixth resistor is connected to the second sampling input terminal, the second end of the sixth resistor is connected to the first end of the pulse input unit, both ends of the fifth resistor and the sixth resistor are respectively connected in parallel with the filtering unit, and the second end of the fifth resistor and the second end of the sixth resistor are grounded.

[0026] Preferably, the sampling unit further includes a holding circuit and a conditioning circuit. The first end of the conditioning circuit is connected to the holding circuit, and the second end of the conditioning circuit is connected to the control unit;

[0027] The holding circuit includes a first holding unit and a second holding unit;

[0028] The first holding unit includes a first capacitor, a first switch, a reference voltage source, a second switch, and a seventh resistor. The first end of the first capacitor is connected to the first sampling input terminal, the second end of the first capacitor is respectively connected to the first end of the first switch and the first end of the second switch, the second end of the first switch is connected to the first end of the reference voltage source, the second end of the reference voltage source is grounded, the second end of the second switch is connected to the first end of the seventh resistor, and the second end of the seventh resistor is connected to the conditioning circuit;

[0029] The second holding unit includes a second capacitor, a third switch, a fourth switch, and an eighth resistor. The first end of the second capacitor is connected to the second sampling input terminal, the second end of the second capacitor is respectively connected to the first end of the third switch and the first end of the fourth switch, the second end of the third switch is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the conditioning circuit, and the second end of the fourth switch is grounded;

[0030] The control unit is configured to control the second switch and the fourth switch to be disconnected when the first switch and the third switch are closed; and control the second switch and the fourth switch to be closed when the first switch and the third switch are disconnected.

[0031] Preferably, the control unit is further configured to determine the insulation resistance value according to the voltage of the first sampling input terminal, the voltage of the second sampling input terminal, the reference voltage source, and the output voltage of the pulse input unit.

[0032] Preferably, it further includes a grounding terminal and a ground wire detection signal source. The grounding terminal includes a first grounding terminal and a second grounding terminal connected to each other. The second end of the pulse input unit is connected to the ground through the first grounding terminal; the first end of the ground wire detection signal source is connected to the control unit, and the second end of the ground wire detection signal source is connected to the ground through the second grounding terminal;

[0033] The control unit is configured to determine whether the grounding terminal is disconnected according to the voltage signal at the connection point between the pulse input unit and the grounding terminal.

[0034] Preferably, the high-voltage input terminal is connected to the AC voltage network and / or the DC voltage network of the monitored system.

[0035] An embodiment of the present invention further provides a track auxiliary inverter system, including an auxiliary inverter, an AC voltage network, a DC voltage network, and the insulation monitoring device as described above.

[0036] An embodiment of the present invention further provides an insulation monitoring method for performing insulation monitoring on an AC voltage network or a DC voltage network, and performing insulation monitoring on the monitored system through the insulation monitoring device as described in any one of the above.

[0037] An embodiment of the present invention further provides a readable storage medium, on which an insulation monitoring program is stored. When the insulation monitoring program is executed by a processor, the steps of the insulation monitoring method as described above are implemented.

[0038] An embodiment of the present invention further provides an insulation monitoring device, including a memory, a processor, and an insulation monitoring program stored on the memory and executable on the processor. When the insulation monitoring program is executed by the processor, the steps of the insulation monitoring method as described above are implemented.

[0039] The insulation monitoring device, system, method, device, medium, and auxiliary inverter system according to the embodiments of the present invention inject pulse signals into the ground and the sampling unit respectively through the pulse input unit, and can still ensure accurate measurement when a part of the cable connected to the monitored system is disconnected. Moreover, the embodiments of the present invention can also input a voltage through the disconnection detection signal source input unit before inputting the pulse signal, and sample the voltage at the second end of the high-resistance isolation unit to identify whether the insulation monitoring device is well connected before operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of the insulation monitoring device provided by an embodiment of the present invention;

[0041] Figure 2 is a schematic diagram of the insulation monitoring device provided by another embodiment of the present invention;

[0042] Figure 3 It is a schematic diagram of the disconnection detection signal source input unit, high-resistance isolation unit, sampling unit, and pulse input unit of the insulation monitoring device provided by the embodiments of the present invention;

[0043] Figure 4 It is a schematic diagram of the sampling unit in the insulation monitoring device provided by the embodiments of the present invention;

[0044] Figure 5 It is a schematic diagram of the sampling signal obtained by sampling the sampling unit of the insulation monitoring device under normal conditions according to the embodiments of the present invention;

[0045] Figure 6 It is a schematic diagram of the sampling signal obtained by sampling the sampling unit when the insulation monitoring device provided by the embodiments of the present invention is disconnected from a single monitored line;

[0046] Figure 7 It is a schematic flowchart of the insulation monitoring method provided by the embodiments of the present invention. Detailed implementation manners

[0047] In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0048] As Figure 1 shown, it is a schematic diagram of the insulation monitoring device provided by the embodiments of the present invention. This insulation monitoring device can be used in an IT power supply system (i.e., a power supply system with an unearthed neutral point), such as an urban rail power supply system, especially for monitoring the ground fault on the DC side or AC side of an urban rail auxiliary inverter. The insulation monitoring device of this embodiment includes a high-resistance isolation unit 11, a pulse input unit 12, a sampling unit 13, and a control unit 14. The above high-resistance isolation unit 11, pulse input unit 12, sampling unit 13, and control unit 14 can be specifically composed of circuits and electronic components integrated into a printed circuit board (PCB). The first end of the above insulation monitoring device is connected to the monitored system (such as the three-phase AC line or DC bus of an urban rail auxiliary inverter), and the second end of this insulation monitoring device is connected to the ground.

[0049] Specifically, in this embodiment, the control unit 14 is electrically connected to the sampling unit 13 and the pulse input unit 12 respectively. The above-mentioned sampling unit 13 includes a first sampling input terminal, a second sampling input terminal and a sampling output terminal; the first end of the high-impedance isolation unit 11 is connected to the monitored system through the high-voltage input terminal 17, and the voltage of the monitored system connected to the high-voltage input terminal 17 is isolated and output through its second end. The first sampling input terminal and the second sampling input terminal of the sampling unit 13 are respectively connected to the second end of the high-impedance isolation unit 11, and sample the output voltage of the second end of the high-impedance isolation unit 11; the first end of the pulse input unit 12 is connected to the sampling unit 13, and the second end of the pulse input unit 12 is connected to the ground through the ground terminal 16; the control unit 14 is used to control the pulse input unit 12 to input a pulse to the sampling unit 13 (this pulse signal can specifically be a pulse square wave adaptively adjusted according to the system leakage capacitance, and the acquisition method of this adaptively adjusted pulse square wave belongs to the prior art in this field and will not be elaborated here), and determine the insulation resistance value of the monitored system according to the signal at the sampling output terminal.

[0050] The insulation resistance value of the above-mentioned monitored system includes the status signal of the monitored system, that is, whether the monitored system has a single-point-to-ground fault can be confirmed by analyzing the insulation resistance value of the monitored system. Specifically, the control unit 14 can output the insulation resistance value of the above-mentioned monitored system to the monitored system (for example, output to the controller of the auxiliary inverter or other upper computers).

[0051] After the power-on of the insulation monitoring device in this embodiment is completed, the control unit 14 controls the pulse input unit 12 to output a pulse signal to the ground (for example, a low-frequency square wave signal of + / -30V), combined with Figure 2 As shown, the pulse signal output by the pulse input unit 12 forms a closed insulation resistance value (that is, the ground resistance of the monitored system) measurement loop through the ground terminal 16 → the insulation resistance RX and leakage capacitance CX of the monitored system → the monitored system → the high-impedance isolation unit 11. Through signal processing of the voltage at the second end of the high-impedance isolation unit 11 by the sampling unit 13, after the control unit 14 performs analog-to-digital conversion and calculation, the monitoring signal related to the ground resistance of the monitored system (that is, the insulation resistance value of the monitored system) is converted into a digital signal and output.

[0052] Combined with Figure 2As shown, in an embodiment of the present invention, the high-voltage input terminal includes a first high-voltage terminal L1 and a second high-voltage terminal L2, and the high-impedance isolation unit 11 includes a voltage-dividing unit connected between the first sampling input terminal and the second sampling input terminal. That is, the high-impedance isolation unit 11 is connected to two different points of the monitored system through the first high-voltage terminal L1 and the second high-voltage terminal L2, such as two of the three-phase AC lines of the urban rail auxiliary inverter or the positive and negative DC buses, so that the fault point can be obtained through multi-point monitoring.

[0053] Combined with Figure 3 As shown, the above-mentioned high-impedance isolation unit 11 specifically includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the first high-voltage terminal L1, and the second end of the first resistor R1 (i.e., Figure 3 the potential sampling point a1 therein) is connected to the first sampling input terminal of the sampling unit 13; the first end of the second resistor R2 is connected to the second high-voltage terminal L2, and the second end of the second resistor R2 (i.e., Figure 3 the potential sampling point a2 therein) is connected to the second sampling input terminal of the sampling unit 13. The above-mentioned first resistor R1 and second resistor R2 can respectively realize the isolated output of two paths of high voltage of the monitored system.

[0054] In particular, to simplify subsequent calculation operations and circuit complexity, the resistance values of the above-mentioned first resistor R1 and second resistor R2 can be made equal.

[0055] In addition, the voltage-dividing unit between the first sampling input terminal and the second sampling input terminal of the sampling unit 13 specifically includes a third resistor R3. One end of the third resistor R3 is connected to the second end of the first resistor R1, and the other end is connected to the second end of the second resistor R2. Through the third resistor R3, isolation between the first sampling input terminal and the second sampling input terminal can be achieved.

[0056] Combined with Figure 3 As shown, the sampling unit 13 further includes a fifth resistor R5, a sixth resistor R6 and a filtering unit. The first end of the fifth resistor R5 is connected to the first sampling input terminal, and the second end of the fifth resistor R5 is connected to the first end of the pulse input unit 12; the first end of the sixth resistor R6 is connected to the second sampling input terminal, and the second end of the sixth resistor R6 is connected to the first end of the pulse input unit 12. The two ends of the above-mentioned fifth resistor R5 and sixth resistor R6 are respectively connected in parallel with the filtering unit, and the second ends of the fifth resistor R5 and the sixth resistor R6 are grounded. The above-mentioned sampling unit 13 forms two detection signals through the fifth resistor R5 and the sixth resistor R6. The filtering unit can perform filtering and DC isolation processing to eliminate the influence of the system power frequency voltage and DC voltage on the insulation resistance measurement circuit.

[0057] Combined with Figure 4As shown, the sampling unit 13 further includes a holding circuit and a conditioning circuit, wherein the first end of the conditioning circuit is connected to the holding circuit, and the second end of the conditioning circuit is connected to the control unit 14. Specifically, corresponding to the two detection signals of the sampling unit 13, the holding circuit includes a first holding unit and a second holding unit.

[0058] Among them, the first holding unit includes a first capacitor C1, a first switch S1, a reference voltage source REF1, a second switch S2, and a seventh resistor R7. The first end of the first capacitor C1 is connected to the first sampling input terminal, and the second end of the first capacitor C1 is respectively connected to the first end of the first switch S1 and the first end of the second switch S2. The second end of the first switch S1 is connected to the first end of the reference voltage source REF1, the second end of the reference voltage source REF1 is grounded, the second end of the second switch S2 is connected to the first end of the seventh resistor R7, and the second end of the seventh resistor R7 is connected to the conditioning circuit; the second holding unit includes a second capacitor C2, a third switch S3, a fourth switch S4, and an eighth resistor R8. The first end of the second capacitor C2 is connected to the second sampling input terminal, and the second end of the second capacitor C2 is respectively connected to the first end of the third switch S3 and the first end of the fourth switch S4. The second end of the third switch S3 is connected to the first end of the eighth resistor R8, the second end of the eighth resistor R8 is connected to the conditioning circuit, and the second end of the fourth switch S4 is grounded.

[0059] The control unit 14 is configured to control the second switch S2 and the fourth switch S4 to be disconnected when the first switch S1 and the third switch S3 are closed; and control the second switch S2 and the fourth switch S4 to be closed when the first switch S1 and the third switch S3 are disconnected. Specifically, when the insulation monitoring device is operating stably, the control unit 14 controls the pulse input unit 12 to output a pulse signal to the grounding terminal 16. The control unit 14 also outputs a first control signal to the first switch element S1 and the third switch element S3 respectively, and outputs a second control signal to the second switch element S2 and the fourth switch element S4 respectively. The above-mentioned first control signal, second control signal, and preset pulse signal are respectively square wave pulses (the duty cycle thereof is adaptively adjusted by the control unit 14 according to the feedback of the sampling value). The first control signal is inverted with respect to the second control signal, and the phase of the second control signal is offset from the phase of the preset pulse signal.

[0060] The above-mentioned control unit 14 is further configured to determine the insulation resistance value of the monitored system according to the voltage of the first sampling input terminal, the voltage of the second sampling input terminal, the reference voltage source REF1, and the output voltage of the pulse input unit 12.

[0061] Combined with Figure 3As shown in the figure, the pulse input unit 12 of this embodiment may specifically include a fifth switching element S5, a sixth switching element S6, a first DC power supply REF2, and a second DC power supply REF3. The negative electrode (i.e., the low potential end) of the first DC power supply REF2 is connected to the reference ground GND, and the positive electrode (i.e., the high potential end) of the second DC power supply REF3 is connected to the reference ground GND. The positive electrode (i.e., the high potential end) of the first DC power supply REF2 is connected to the grounding terminal 16 via the fifth switching element S5, and the negative electrode (i.e., the low potential end) of the second DC power supply REF3 is connected to the grounding terminal 16 via the sixth switching element S6. The control terminals of the fifth switching element S5 and the sixth switching element S6 are respectively connected to the control unit 14 and are respectively turned on or off according to the control signals SS_1(+) and SS_1(-) from the control unit 14.

[0062] The above-mentioned first switching element S1, second switching element S2, third switching element S3, fourth switching element S4, fifth switching element S5, and sixth switching element S6 may specifically adopt semiconductor switching elements, relays, contactors, etc.

[0063] Combined Figure 5 As shown in the figure, when the insulation monitoring device is working normally (both high-voltage connection terminals L1 and L2 are well-connected), in the sampling waveform diagram, the voltages of the potential sampling points a1 and a2 are basically the same. The voltage AIN_M collected by the sampling unit 13 satisfies the following calculation formula at different time points:

[0064] (V M1 -V REF1 )=(V REF2 -V M2 ) (1)

[0065] Among them, V REF1 is the sampling voltage when the first switching element S1 and the third switching element S3 are closed, the second switching element S2 and the fourth switching element S4 are open, and the preset pulse signal is at a low level. V M1 is the sampling voltage when the first switching element S1 and the third switching element S3 are closed, the second switching element S2 and the fourth switching element S4 are open, and the preset pulse signal is at a high level. V REF2 is the sampling voltage when the first switching element S1 and the third switching element S3 are open, the second switching element S2 and the fourth switching element S4 are closed, and the preset pulse signal is at a high level. V M2 is the sampling voltage when the first switching element S1 and the third switching element S3 are open, the second switching element S2 and the fourth switching element S4 are closed, and the preset pulse signal is at a low level. The insulation resistance value can be calculated through the voltage change amount in the above calculation formula (4) (the calculation method of the insulation resistance value is a well-known technology in the art and will not be elaborated here), so as to confirm the state of the monitored system.

[0066] Assume that the first high-voltage terminal L1 is disconnected and the second high-voltage terminal L2 is in good connection. When the pulse signal output by the pulse input unit 12 changes, the voltage change at the potential sampling point a1 is extremely small, while the voltage change at the potential sampling point a2 is relatively large. When the voltages at the potential sampling points a1 and a2 have stabilized before entering the next measurement cycle, the sampling waveform diagram of the sampling voltage AIN_M is as Figure 6 shown. At this time, since the resistance of the monitored system is different from that in the normal state (i.e., the first high-voltage terminal L1 and the second high-voltage terminal L2 are in good connection), by calculating the insulation resistance value using the voltage change amount (V M1 -V REF1 ) in the first half cycle, the accuracy of the measurement result can be improved. When the second high-voltage terminal L2 is disconnected from the monitored system, a similar method can be used for processing.

[0067] In the above manner, during the operation of the insulation monitoring device, when an accident occurs and the first high-voltage terminal L1 or the second high-voltage terminal L2 is disconnected, the above insulation monitoring device can still calculate the change in the insulation resistance value based on the change in the sampling voltage through a high-voltage terminal that is in good connection with the monitored system, ensuring the accuracy of the measurement data. In addition, during the operation of the insulation monitoring device, if a high-voltage connection terminal is disconnected, the control unit 14 can also output an alarm signal through the fault indication unit.

[0068] Combined with Figure 2 、 3 shown, in another embodiment of the present invention, the above insulation monitoring device can also detect whether it is in good connection with the monitored system before formal work (i.e., before the pulse input unit 12 outputs a pulse signal to the ground). In this embodiment, in addition to the control unit 14, the high-resistance isolation unit 11, the sampling unit 13, and the pulse input unit 12, the insulation monitoring device further includes a disconnection detection signal source input unit 15. The disconnection detection signal source input unit 15 is connected to the second end of the high-resistance isolation unit 11, and the disconnection detection signal source input unit 15 is also connected to the control unit 14.

[0069] When the pulse of the pulse input unit 12 is turned off (for example, when the insulation monitoring device is just powered on and the pulse input unit 12 does not output a pulse signal), the control unit 14 controls the signal source of the disconnection detection signal source input unit 15 to be turned on, and obtains the voltage at the first sampling input terminal and / or the second sampling input terminal, and determines whether the high-voltage input terminal is disconnected according to the voltage at the first sampling input terminal and / or the second sampling input terminal. After the above detection is completed (that is, it is detected and confirmed that the insulation monitoring device is well connected to the monitored system), the control unit 14 controls the pulse of the pulse input unit 12 to be turned on (that is, outputs a pulse signal), and at the same time controls the signal source of the disconnection detection signal source input unit 15 to be turned off, and obtains the voltage signal at the sampling output terminal, and determines the insulation resistance value of the monitored system according to the voltage signal at the sampling output terminal.

[0070] In an embodiment of the present invention, the disconnection detection signal source input unit 15 is connected to the first sampling input terminal; when the pulse of the pulse input unit 12 is turned off, the control unit 14 controls the signal source of the disconnection detection signal source input unit 15 to be turned on, and obtains the voltage signal at the second sampling input terminal, and determines whether the high-voltage input terminal is disconnected according to the voltage signal at the second sampling input terminal.

[0071] Alternatively, in another embodiment of the present invention, the disconnection detection signal source input unit 15 is connected to the second sampling input terminal. When the pulse of the pulse input unit 12 is turned off, the control unit 14 controls the signal source of the disconnection detection signal source input unit 15 to be turned on, and obtains the voltage signal at the first sampling input terminal, and determines whether the high-voltage input terminal is disconnected according to the voltage signal at the first sampling input terminal.

[0072] The above disconnection detection signal source input unit 15 includes a signal source input terminal and a fourth resistor R4, wherein the signal source input terminal is connected to the fourth resistor R4, and the fourth resistor R4 is connected to the first sampling input terminal or the second sampling input terminal. And a switching unit (such as a semiconductor switch tube or a contactor) is connected between the signal source input terminal and the fourth resistor R4. The control unit 14 controls the connection or disconnection between the disconnection detection signal source input unit 15 and the sampling unit 13 by controlling the on / off of the switching unit. At the same time, the control unit 14 also determines the voltage at the first sampling input terminal or the second sampling input terminal according to the resistance values of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4 and the input voltage of the disconnection detection signal source input unit 15, so as to judge whether the insulation detection device is well connected to the monitored system.

[0073] The following takes the connection of the first high-voltage terminal L1 and the second high-voltage terminal L2 to the monitored system as an example to specifically illustrate the connection state judgment of the above insulation monitoring device through the disconnection detection signal source input unit 15.

[0074] When the disconnection detection signal source input unit 15 is connected to the sampling unit 13, assuming that both the first high-voltage terminal L1 and the second high-voltage terminal L2 of the insulation monitoring device are disconnected from the monitored system, or the grounding terminal 16 is disconnected from the ground, the insulation resistance measurement circuit (i.e., the closed circuit formed by the grounding terminal 16 → the insulation resistance RX and leakage capacitance CX of the monitored system → the monitored system → the high-voltage isolation unit 11) is disconnected. Even if an insulation fault occurs in the monitored system, the insulation resistance measured by the insulation monitoring device (i.e., the resistance of the monitored system to the ground) is still extremely large, equivalent to the device failure. The insulation monitoring device of this embodiment specifically avoids the above situation in the following way:

[0075] Combined Figure 3 As shown, the switching unit in the disconnection detection signal source input unit 15 is turned on under the control signal SL1 of the control unit 14. Since the voltages at the first sampling input terminal or the second sampling input terminal of the sampling unit 13 are different when both the first high-voltage terminal L1 and the second high-voltage terminal L2 are well-connected to the monitored system and when any one of them is disconnected from the monitored system, by judging the voltage value at the first sampling input terminal or the second sampling input terminal, it is possible to determine whether the first high-voltage terminal L1 and the second high-voltage terminal L2 are well-connected to the system.

[0076] Specifically, when the voltage value at the potential sampling point a2 is stable, it is possible to determine whether there is a disconnection in the high-voltage line. At this time, the output voltage U L of the disconnection detection signal source input unit 15 and the voltage value U2 at the potential sampling point a2 have the following relationship:

[0077]

[0078] where " / / " represents the resistance value of resistors in parallel, R2 represents the resistance value of the second resistor R2, R4 represents the resistance value of the fourth resistor R4, and R' is the insulation resistance value. When both the first high-voltage terminal L1 and the second high-voltage terminal L2 are well-connected to the monitored system, the insulation resistance value R' satisfies the following calculation formula (3); when one or more of the first high-voltage terminal L1 and the second high-voltage terminal L2 are disconnected from the monitored system, it satisfies the following calculation formula (4):

[0079] R' = (2 × R1) / / R3 (3)

[0080] R' = R3 (4)

[0081] where R1 represents the resistance value of the third resistor R1, and R3 represents the resistance value of the third resistor R3.

[0082] After the above disconnection detection is completed, the control unit 14 turns off the output of the disconnection detection signal source input unit 15. When it is confirmed that both the first high-voltage terminal L1 and the second high-voltage terminal L2 are well connected, the insulation resistance measurement circuit is started to work. Since it conflicts with the real-time monitoring of the insulation resistance, the disconnection detection of the first high-voltage terminal L1 and the second high-voltage terminal L2 is only performed when the insulation monitoring device is powered on.

[0083] Specifically, the insulation monitoring device may further include a fault indication unit, which is connected to the control unit 14. When one or more of the first high-voltage terminal L1 and the second high-voltage terminal L2 are disconnected from the monitored system, the control unit 14 can output an alarm signal through the fault indication unit.

[0084] Combined Figure 2 As shown, in another embodiment of the present invention, the insulation monitoring device may further include a conditioning unit 10. The grounding terminal 16 includes a first grounding end E and a second grounding end KE respectively used for connecting to the ground. The first grounding end E is connected to the pulse input unit 12 and outputs the pulse signal output by the pulse input unit 12 to the ground. The second grounding end K3 is connected to the control unit 14 via the conditioning unit 10, and the conditioning unit 10 adjusts the voltage of the second grounding end K3 to a preset range and then outputs it to the control unit 14. Thus, the control unit 14 can judge whether the grounding terminal 16 has abnormal grounding according to the signal AIN_KE (voltage signal) received from the conditioning unit 10.

[0085] Specifically, when the signal AIN_KE received from the conditioning unit 10 does not include the signal corresponding to the preset pulse signal (from the pulse input unit 12), the control unit 14 confirms that there is a grounding fault in the grounding terminal 16. When the signal AIN_KE received from the conditioning unit 10 includes the signal corresponding to the pulse signal, the control unit 14 confirms that there is no grounding fault in the grounding terminal 16. And when the control unit 14 confirms that there is a grounding fault in the grounding terminal 16, an alarm signal can also be output through the fault indication unit.

[0086] By detecting the disconnection of the first high-voltage terminal L1 and the second high-voltage terminal L2 and the disconnection of the grounding terminal 16 when the insulation monitoring device is powered on, it can be identified whether the insulation monitoring device is well connected to the system before operation, providing a reference for the debugging personnel and preventing the insulation monitoring device from being unable to measure the insulation resistance value due to disconnection. And the disconnection detection of the grounding terminal 16 is carried out simultaneously with the process of obtaining the insulation resistance value through the pulse input unit 12, the sampling unit 13 and the control unit 14, and is monitored in real time.

[0087] In one embodiment of the present invention, the above-mentioned insulation monitoring device further includes an analog quantity output unit 19, which converts the digital signal output by the control unit 14 into an analog quantity (such as 0-10V) and outputs it. Through the analog quantity output unit 19, the above-mentioned insulation monitoring device can output the monitoring signal related to the ground resistance of the monitored system in real time in a simple manner (without communication).

[0088] In another embodiment of the present invention, the above-mentioned insulation monitoring device may further include a DC input terminal and a power supply unit 20; the power supply unit 20 is connected to the DC input unit to obtain externally input direct current (such as 24V), and the power supply unit 20 uses an isolated power supply circuit to generate other power supplies required by the insulation monitoring device, and outputs DC supply voltages to the control unit 14, the sampling unit 13 (such as the reference voltage source REF1), and the pulse input unit 12 (such as the first DC power supply REF2, the second DC power supply REF3) respectively.

[0089] An auxiliary inverter system for railways includes an auxiliary inverter, an AC voltage network, a DC voltage network, and the above-mentioned insulation monitoring device;

[0090] The insulation monitoring device is connected to the first end of the ninth resistor and the first end of the third capacitor, and the second ends of the ninth resistor and the third capacitor are connected to the AC voltage network and / or the DC voltage network.

[0091] An embodiment of the present invention further provides an auxiliary inverter system for railways (i.e., an auxiliary inverter system), which includes an auxiliary inverter, an AC voltage network, a DC voltage network, and the insulation monitoring device as described above. The auxiliary inverter system in this embodiment and the insulation monitoring device in the corresponding embodiment above belong to the same concept. The specific implementation process is detailed in the corresponding device embodiment, and the technical features in the device embodiment are all correspondingly applicable in this embodiment, and will not be elaborated here. Figures 1-6 The insulation monitoring device in the corresponding embodiment belongs to the same concept. The specific implementation process is detailed in the corresponding device embodiment, and the technical features in the device embodiment are all correspondingly applicable in this method embodiment, and will not be elaborated here.

[0092] An embodiment of the present invention further provides an insulation monitoring method for insulating the AC voltage network or the DC voltage network. This method uses the above-mentioned insulation monitoring device to monitor the insulation of the monitored system. The insulation monitoring method in this embodiment and the insulation monitoring device in the corresponding embodiment above belong to the same concept. The specific implementation process is detailed in the corresponding device embodiment, and the technical features in the device embodiment are all correspondingly applicable in this method embodiment, and will not be elaborated here. Figures 1-6 The insulation monitoring device in the corresponding embodiment belongs to the same concept. The specific implementation process is detailed in the corresponding device embodiment, and the technical features in the device embodiment are all correspondingly applicable in this method embodiment, and will not be elaborated here.

[0093] An embodiment of the present invention also provides a computer-readable storage medium, on which an insulation monitoring program is stored. When the insulation monitoring program is executed by a processor, the steps of the insulation monitoring method described above are implemented. The readable storage medium in this embodiment and the insulation monitoring device in the corresponding Figures 1-6 embodiment belong to the same concept. The specific implementation process is detailed in the corresponding device embodiment, and the technical features in the device embodiment are all correspondingly applicable in this embodiment, which will not be elaborated here.

[0094] An embodiment of the present invention also provides an insulation monitoring device, including a memory, a processor, and an insulation monitoring program stored on the memory and executable on the processor. When the insulation monitoring program is executed by the processor, the steps of the insulation monitoring method described above are implemented. The insulation monitoring device in this embodiment and the insulation monitoring device in the corresponding Figures 1-6 embodiment belong to the same concept. The specific implementation process is detailed in the corresponding device embodiment, and the technical features in the device embodiment are all correspondingly applicable in this embodiment, which will not be elaborated here.

[0095] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An insulation monitoring device, characterized in that, It includes a control unit, a high-impedance isolation unit, a sampling unit, and a pulse input unit. The first end of the insulation monitoring device is connected to the monitored system, and the second end of the insulation monitoring device is connected to the ground; the control unit is respectively connected to the sampling unit and the pulse input unit; The sampling unit includes a first sampling input terminal, a second sampling input terminal, and a sampling output terminal; The first end of the high-impedance isolation unit is connected to the monitored system through a high-voltage input terminal, and the first sampling input terminal and the second sampling input terminal are respectively connected to the second end of the high-impedance isolation unit; The first end of the pulse input unit is connected to the sampling unit, and the second end of the pulse input unit is connected to the ground; The control unit is used to control the pulse input unit to input a pulse to the sampling unit, and determine the insulation resistance value of the monitored system according to the signal of the sampling output terminal. The pulse input to the sampling unit is a pulse square wave adaptively adjusted according to the system leakage capacitance; The insulation monitoring device further includes a disconnection detection signal source input unit. The disconnection detection signal source input unit is connected to the second end of the high-impedance isolation unit, and the disconnection detection signal source input unit is also connected to the control unit; When the pulse of the pulse input unit is turned on, the control unit controls the signal source of the disconnection detection signal source input unit to be turned off, and obtains the voltage signal of the sampling output terminal, and determines the insulation resistance value of the monitored system according to the voltage signal of the sampling output terminal; When the pulse of the pulse input unit is turned off, the control unit controls the signal source of the disconnection detection signal source input unit to be turned on, and obtains the voltage of the first sampling input terminal and / or the second sampling input terminal, and determines whether the high-voltage input terminal is disconnected according to the voltage of the first sampling input terminal and / or the second sampling input terminal.

2. The insulation monitoring device according to claim 1, characterized in that, The high-voltage input terminal includes a first high-voltage terminal and a second high-voltage terminal, and the high-impedance isolation unit includes a voltage dividing unit connected between the first sampling input terminal and the second sampling input terminal.

3. The insulation monitoring device according to claim 2, characterized in that, The high-impedance isolation unit includes a first resistor and a second resistor. The first end of the first resistor is connected to the first high-voltage terminal, the second end of the first resistor is connected to the first sampling input terminal, the first end of the second resistor is connected to the second high-voltage terminal, and the second end of the second resistor is connected to the second sampling input terminal.

4. The insulation monitoring device according to claim 3, characterized in that, The resistance values of the first resistor and the second resistor are equal.

5. The insulation monitoring device according to claim 3, characterized in that, The voltage dividing unit includes a third resistor. One end of the third resistor is connected to the second end of the first resistor, and the other end is connected to the second end of the second resistor.

6. The insulation monitoring device according to claim 5, characterized in that, The disconnection detection signal source input unit is connected to the first sampling input terminal; when the pulse of the pulse input unit is turned off, the control unit controls the signal source of the disconnection detection signal source input unit to be turned on, and obtains the voltage signal of the second sampling input terminal, and determines whether the high-voltage input terminal is disconnected according to the voltage signal of the second sampling input terminal; Or, The disconnection detection signal source input unit is connected to the second sampling input terminal; When the pulse of the pulse input unit is turned off, the control unit controls the signal source of the disconnection detection signal source input unit to turn on, obtains the voltage signal of the first sampling input terminal, and determines whether the high-voltage input terminal is disconnected according to the voltage signal of the first sampling input terminal.

7. The insulation monitoring device according to claim 6, characterized in that, The disconnection detection signal source input unit includes a signal source input terminal and a fourth resistor. The signal source input terminal is connected to the fourth resistor, and the fourth resistor is connected to the first sampling input terminal or the second sampling input terminal.

8. The insulation monitoring device according to claim 7, characterized in that, The control unit is further configured to determine the voltage of the first sampling input terminal or the second sampling input terminal according to the resistance values of the first resistor, the second resistor, the third resistor, the fourth resistor, and the input voltage of the disconnection detection signal source input unit.

9. The insulation monitoring device according to claim 7, characterized in that, A switching unit is connected between the signal source input terminal and the fourth resistor, and the control unit controls the on / off of the switching unit.

10. The insulation monitoring device according to claim 1, characterized in that, The sampling unit further includes a fifth resistor, a sixth resistor, and a filtering unit. The first end of the fifth resistor is connected to the first sampling input terminal, the second end of the fifth resistor is connected to the first end of the pulse input unit, the first end of the sixth resistor is connected to the second sampling input terminal, the second end of the sixth resistor is connected to the first end of the pulse input unit, both ends of the fifth resistor and the sixth resistor are respectively connected in parallel with the filtering unit, and the second ends of the fifth resistor and the sixth resistor are grounded.

11. The insulation monitoring device according to claim 10, characterized in that, The sampling unit further includes a holding circuit and a conditioning circuit. The first end of the conditioning circuit is connected to the holding circuit, and the second end of the conditioning circuit is connected to the control unit. The holding circuit includes a first holding unit and a second holding unit. The first holding unit includes a first capacitor, a first switch, a reference voltage source, a second switch, and a seventh resistor. The first end of the first capacitor is connected to the first sampling input terminal, the second end of the first capacitor is respectively connected to the first end of the first switch and the first end of the second switch, the second end of the first switch is connected to the first end of the reference voltage source, the second end of the reference voltage source is grounded, the second end of the second switch is connected to the first end of the seventh resistor, and the second end of the seventh resistor is connected to the conditioning circuit. The second holding unit includes a second capacitor, a third switch, a fourth switch, and an eighth resistor. The first end of the second capacitor is connected to the second sampling input terminal, the second end of the second capacitor is respectively connected to the first end of the third switch and the first end of the fourth switch, the second end of the third switch is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the conditioning circuit, and the second end of the fourth switch is grounded. The control unit is configured to control the second switch and the fourth switch to be turned off when the first switch and the third switch are closed; and control the second switch and the fourth switch to be turned on when the first switch and the third switch are turned off.

12. The insulation monitoring device according to claim 11, characterized in that, The control unit is further configured to determine the insulation resistance value according to the voltage of the first sampling input terminal, the voltage of the second sampling input terminal, the reference voltage source, and the output voltage of the pulse input unit.

13. The insulation monitoring device according to claim 1, characterized in that,It further includes a grounding terminal and a ground wire detection signal source. The grounding terminal includes a first grounding terminal and a second grounding terminal which are connected to each other. The second end of the pulse input unit is connected to the ground through the first grounding terminal; the first end of the ground wire detection signal source is connected to the control unit, and the second end of the ground wire detection signal source is connected to the ground through the second grounding terminal; The control unit is configured to determine whether the grounding terminal is open-circuited according to the voltage signal at the connection point between the pulse input unit and the grounding terminal.

14. An insulation monitoring device according to claim 1, wherein, The high-voltage input terminal is connected to the AC voltage network and / or DC voltage network of the monitored system.

15. An auxiliary inverter system for a track, wherein, It includes an auxiliary inverter, an AC voltage network, a DC voltage network, and the insulation monitoring device according to any one of claims 1 to 14.

16. An insulation monitoring method for performing insulation monitoring on an AC voltage network or a DC voltage network, wherein, The monitored system is subjected to insulation monitoring by the insulation monitoring device according to any one of claims 1 to 14.

17. A readable storage medium, wherein, An insulation monitoring program is stored on the readable storage medium. When the insulation monitoring program is executed by a processor, the steps of the insulation monitoring method according to claim 16 are implemented.

18. An insulation monitoring device, wherein, It includes a memory, a processor, and an insulation monitoring program stored on the memory and executable on the processor. When the insulation monitoring program is executed by the processor, the steps of the insulation monitoring method according to claim 16 are implemented.

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