CN215833500U - High-precision direct-current power distribution system insulation resistance monitoring circuit and monitoring device - Google Patents
High-precision direct-current power distribution system insulation resistance monitoring circuit and monitoring device Download PDFInfo
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- CN215833500U CN215833500U CN202122116504.8U CN202122116504U CN215833500U CN 215833500 U CN215833500 U CN 215833500U CN 202122116504 U CN202122116504 U CN 202122116504U CN 215833500 U CN215833500 U CN 215833500U
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Abstract
The utility model discloses an insulation resistance monitoring circuit and a monitoring device of a high-precision direct current power distribution system, wherein the monitoring circuit comprises a measuring resistance network and a voltage measuring circuit; the measuring resistance network comprises a first variable resistance unit, a second variable resistance unit, a first switch unit and a second switch unit, wherein the first variable resistance unit and the second variable resistance unit are sequentially connected between the positive pole and the negative pole of the direct-current power distribution power supply in series; the voltage measuring circuit is connected with a voltage measuring circuit of a voltage value connected between the positive electrode and the negative electrode of the direct current power distribution power supply and the ground. When the insulation resistance changes, the resistance value of the measuring resistor network can be adjusted to track the change of the insulation resistance in real time, the change is always kept about 2 times of the insulation resistance, the insulation level of the whole system can not be reduced by the measuring circuit, and the monitoring precision of the insulation resistance can be improved.
Description
Technical Field
The utility model relates to a high-precision direct current power distribution system insulation resistance monitoring circuit and a monitoring device.
Background
In a low-voltage direct-current power distribution system, particularly in a highway direct-current remote power supply system, due to the fact that working conditions of cables, converters and the like are severe, lines and other insulating materials can be aged rapidly and even damaged in an insulating mode due to vibration, corrosion, temperature and humidity changes and the like, and personal and equipment safety is endangered.
At present, insulation monitoring technologies of direct current systems in places such as power plants, transformer substations and electric vehicles have multiple modes, but all have some defects, such as low sensitivity of a relay detection mode, incapability of accurately and timely alarming when the insulation of a positive electrode and a negative electrode is reduced by a balanced bridge method, increase of direct current system ripples and influence on power supply quality by injecting an alternating current signal method, direct influence on a measurement result by distributed capacitance of the system, and low resolution. The commonly used method for measuring the merged resistance of the electric automobile for multiple times artificially reduces the insulation resistance of a direct current system, and is easy to cause potential safety hazards in the measuring process. In addition, the insulation resistance of the direct current distribution system has a very large variation range from tens of kilohms to hundreds of megaohms, and when the insulation resistance is changed, the monitoring precision cannot be guaranteed.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a high-precision direct current power distribution system insulation resistance monitoring circuit and a monitoring device, which can ensure that a measuring circuit cannot reduce the insulation level of the whole system and can improve the insulation resistance monitoring precision.
In order to solve the technical problem, the utility model provides a high-precision insulation resistance monitoring circuit of a direct current power distribution system, which comprises a measuring resistance network and a voltage measuring circuit, wherein the measuring resistance network comprises a resistor network and a resistor network; the measuring resistance network comprises a first variable resistance unit, a second variable resistance unit, a first switch unit and a second switch unit, wherein the first variable resistance unit and the second variable resistance unit are sequentially connected between the positive pole and the negative pole of the direct-current power distribution power supply in series; the voltage measuring circuit is connected with a voltage measuring circuit of a voltage value connected between the positive electrode and the negative electrode of the direct current power distribution power supply and the ground.
Further, the first variable resistance unit includes a first variable resistor, and the first switching unit includes a first switch connected in parallel with the first variable resistor.
Further, the first variable resistance unit includes a first variable resistor and a first constant resistor group including a plurality of first constant resistors of different resistance values, the first variable resistor and the plurality of first constant resistors being connected in series; the first switch unit comprises a first switch and a second switch combination, the first switch is connected with the first variable resistor in parallel, and the first switch combination comprises a plurality of second switches which are respectively connected with the first constant value resistors in the first resistor group in parallel.
Further, the second variable resistance unit includes a second variable resistor, and the second switching unit includes a third switch connected in parallel with the second variable resistor.
Further, the second variable resistance unit includes a second variable resistor and a second fixed-value resistor group, the second fixed-value resistor group includes a plurality of second fixed-value resistors of different resistance values, and the second variable resistor and the plurality of second fixed-value resistors are connected in series; the second switch unit comprises a third switch and a fourth switch combination, the third switch is connected with the first variable resistor in parallel, and the fourth switch combination comprises a plurality of fourth switches respectively connected with the second constant value resistors in the second resistor group in parallel.
Further, a fifth switch and a fifth resistor which are connected in series are connected between the first variable resistance unit and the positive pole of the direct current distribution power supply.
Furthermore, a sixth switch and a sixth resistor which are connected in series between the second variable resistance unit and the negative pole of the direct-current distribution power supply.
In addition, the utility model also provides a high-precision insulation resistance monitoring device of the direct current power distribution system, which comprises the measuring resistance network and a voltage measuring circuit; the output end of the measuring resistance network and the output end of the voltage measuring circuit are respectively connected with the input end of the single chip microcomputer, and the output end of the single chip microcomputer is connected with the human-computer interaction unit.
Furthermore, the human-computer interaction unit comprises an audible and visual alarm and a touch screen which are respectively connected with the output end of the single chip microcomputer.
Furthermore, the output end of the single chip microcomputer is also connected with a communication interface.
The utility model has the beneficial effects that: when the insulation resistance changes, the resistance value of the measuring resistor network can be adjusted to track the change of the insulation resistance in real time, the change is always kept about 2 times of the insulation resistance, the insulation level of the whole system can not be reduced by the measuring circuit, and the monitoring precision of the insulation resistance can be improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:
fig. 1 is a circuit schematic diagram of an insulation resistance monitoring circuit of a high-precision direct current power distribution system.
Fig. 2 is a schematic block diagram of an insulation resistance monitoring device of a high-precision direct-current power distribution system.
Detailed Description
The insulation resistance monitoring circuit of the high-precision direct current power distribution system shown in FIG. 1 comprises a measuring resistance network and a voltage measuring circuit; the measuring resistance network comprises a first variable resistance unit, a second variable resistance unit, a first switch unit and a second switch unit, wherein the first variable resistance unit and the second variable resistance unit are sequentially connected between the positive pole and the negative pole of the direct-current power distribution power supply in series; the voltage measuring circuit is connected with a voltage measuring circuit of a voltage value connected between the positive electrode and the negative electrode of the direct current power distribution power supply and the ground.
When the insulation resistance changes, the resistance value of the measuring resistor network can be adjusted to track the change of the insulation resistance in real time, the change is always kept about 2 times of the insulation resistance, the insulation level of the whole system can not be reduced by the measuring circuit, and the monitoring precision of the insulation resistance can be improved. When the measured resistance is larger than a certain value, the insulation resistance is not affected, and the measured resistance value does not need to be increased without limit.
According to an embodiment of the present application, the first variable resistance unit includes a first variable resistor R1, and the first switching unit includes a first switch K1 connected in parallel with the first variable resistor R1. When the insulation resistance changes, the resistance value of the measuring resistance network is adjusted, so that the change of the insulation resistance R + can be tracked in real time and is always kept about 2 times of the insulation resistance R +. The first variable resistor R1 may be a digital potentiometer controlled by a digital input to generate an analog output. The digital potentiometer adopts a numerical control mode to adjust the resistance value, and has the remarkable advantages of flexible use, high adjustment precision, no contact, low noise, difficult contamination, vibration resistance, interference resistance, small volume, long service life and the like.
According to an embodiment of the present application, the first variable resistance unit includes a first variable resistor R1 and a first set of fixed-value resistors including a number of first fixed-value resistors (R2/R21/R22) of different resistance values, the first variable resistor R1 and the number of first fixed-value resistors (R2/R21/R22) being connected in series; the first switch unit includes a first switch K1 and a second switch combination, the first switch K1 is connected in parallel with the first variable resistor R1, and the first switch K1 combination includes a plurality of second switches (K2/K21/K22) respectively connected in parallel with the first constant value resistors in the first resistance group. In the embodiment, the resistance value of the measuring resistor can be conveniently adjusted by adopting a combination mode of the fixed resistor and the adjustable resistor and then by adjusting the switch combination and the digital potentiometer, so that the measuring resistor tracks the insulation resistance R +. The first variable resistor R1 can adopt a digital potentiometer, the precision is 0.2%, the adjusting range is 0-100k omega, and the total adjusting step number is 1024 steps; the first constant value resistor (R2/R21/R22) can adopt a standard constant value resistor, the precision adopts 0.1% high-precision resistor, the power is 2W, and the first switch K1 and the second switches (K2/K21/K22) can adopt relay contact switches, so that the interference can be avoided.
According to an embodiment of the present application, the second variable resistance unit includes a second variable resistor R3, and the second switching unit includes a third switch K3 connected in parallel with the second variable resistor R3. Similarly, when the insulation resistance changes, the resistance value of the measuring resistance network is adjusted to track the change of the insulation resistance R-in real time and keep the change of the insulation resistance R-to be about 2 times of the insulation resistance R-all the time. The first variable resistor R1 may also be a digital potentiometer.
According to an embodiment of the present application, the second variable resistance unit includes a second variable resistor R3 and a second fixed resistor group including a plurality of second fixed resistors (R4/R41/R42) of different resistance values, the second variable resistor R3 and the plurality of second fixed resistors (R4/R41/R42) being connected in series; the second switch unit comprises a third switch K3 and a fourth switch combination, the third switch K3 is connected with the first variable resistor R1 in parallel, and the fourth switch combination comprises a plurality of fourth switches (K2/K21/K22) which are respectively connected with the second constant value resistors (R4/R41/R42) in the second resistor group in parallel. Similarly, the embodiment can conveniently adjust the resistance value of the measuring resistor to track the insulation resistance R-by adopting a combination of the fixed resistor and the adjustable resistor and then by adjusting the switch combination and adjusting the digital potentiometer.
According to one embodiment of the application, a fifth switch K5 and a fifth resistor R5 which are connected in series are connected between the first variable resistance unit and the positive pole of the direct current distribution power supply. The fifth switch K5 and the fifth resistor R5 are provided to prevent a short circuit from occurring when the resistance of the first variable resistance unit is zero.
According to one embodiment of the application, a sixth switch K6 and a sixth resistor R6 which are connected in series are connected between the second variable resistance unit and the negative pole of the direct current distribution power supply. The sixth switch K6 and the sixth resistor R6 are provided to prevent a short circuit from occurring when the resistance of the fifth variable resistance unit is zero.
As shown in fig. 2, the utility model also discloses a high-precision insulation resistance monitoring device of the direct current power distribution system, which is characterized by comprising the measuring resistance network and a voltage measuring circuit; the output end of the measuring resistance network and the output end of the voltage measuring circuit are respectively connected with the input end of the single chip microcomputer, and the output end of the single chip microcomputer is connected with the human-computer interaction unit. The voltage measuring circuit can adopt a sampling circuit, a filter circuit and a photoelectric isolator which are connected in sequence, the sampling circuit is respectively connected with the positive pole and the negative pole of the direct-current power distribution power supply and the ground, and the output end of the photoelectric isolator is connected with the output end of the single chip microcomputer.
According to one embodiment of the application, the man-machine interaction unit comprises an audible and visual alarm and a touch screen which are respectively connected with the output end of the single chip microcomputer. When the singlechip monitors that the data is abnormal, an audible and visual alarm can be used for giving an alarm prompt; the touch screen is used for displaying monitoring data so as to be convenient for operators to check.
According to an embodiment of the application, the output end of the single chip microcomputer is further connected with a communication interface, so that a worker can conveniently acquire monitoring data monitored by the device.
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (10)
1. A high-precision direct current power distribution system insulation resistance monitoring circuit is characterized by comprising a measuring resistance network and a voltage measuring circuit; the measuring resistance network comprises a first variable resistance unit, a second variable resistance unit, a first switch unit and a second switch unit, wherein the first variable resistance unit and the second variable resistance unit are sequentially connected between the positive pole and the negative pole of the direct-current power distribution power supply in series; the voltage measuring circuit is connected with a voltage measuring circuit of a voltage value connected between the positive electrode and the negative electrode of the direct current power distribution power supply and the ground.
2. The insulation resistance monitoring circuit for high precision direct current power distribution system according to claim 1, wherein the first variable resistance unit includes a first variable resistor, and the first switching unit includes a first switch connected in parallel with the first variable resistor.
3. The insulation resistance monitoring circuit for the high-precision direct current power distribution system according to claim 1, wherein the first variable resistance unit comprises a first variable resistor and a first constant value resistor group, the first constant value resistor group comprises a plurality of first constant value resistors with different resistance values, and the first variable resistor and the plurality of first constant value resistors are connected in series; the first switch unit comprises a first switch and a second switch combination, the first switch is connected with the first variable resistor in parallel, and the first switch combination comprises a plurality of second switches which are respectively connected with the first constant value resistors in the first resistor group in parallel.
4. The insulation resistance monitoring circuit for high-precision direct current power distribution system according to claim 1, wherein the second variable resistance unit includes a second variable resistor, and the second switch unit includes a third switch connected in parallel with the second variable resistor.
5. The insulation resistance monitoring circuit for the high-precision direct current power distribution system according to claim 1, wherein the second variable resistance unit comprises a second variable resistor and a second fixed value resistor group, the second fixed value resistor group comprises a plurality of second fixed value resistors with different resistance values, and the second variable resistor and the plurality of second fixed value resistors are connected in series; the second switch unit comprises a third switch and a fourth switch combination, the third switch is connected with the first variable resistor in parallel, and the fourth switch combination comprises a plurality of fourth switches respectively connected with the second constant value resistors in the second resistor group in parallel.
6. The insulation resistance monitoring circuit for a high-precision direct current power distribution system according to any one of claims 1 to 5, wherein a fifth switch and a fifth resistor connected in series are connected in series between the first variable resistance unit and the positive electrode of the direct current power distribution power supply.
7. The insulation resistance monitoring circuit for the high-precision direct current power distribution system according to any one of claims 1 to 5, wherein a sixth switch and a sixth resistor connected in series are connected in series between the second variable resistance unit and the negative pole of the direct current power distribution power supply.
8. A high precision dc power distribution system insulation resistance monitoring device, comprising a measuring resistor network according to any of claims 1-7 and a voltage measuring circuit; the output end of the measuring resistance network and the output end of the voltage measuring circuit are respectively connected with the input end of the single chip microcomputer, and the output end of the single chip microcomputer is connected with the human-computer interaction unit.
9. The insulation resistance monitoring device for the high-precision direct current power distribution system according to claim 8, wherein the human-computer interaction unit comprises an audible and visual alarm and a touch screen which are respectively connected with the output end of the single chip microcomputer.
10. The insulation resistance monitoring device for the high-precision direct current power distribution system according to claim 8 or 9, wherein the output end of the single chip microcomputer is further connected with a communication interface.
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| CN202122116504.8U CN215833500U (en) | 2021-09-02 | 2021-09-02 | High-precision direct-current power distribution system insulation resistance monitoring circuit and monitoring device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113608028A (en) * | 2021-09-02 | 2021-11-05 | 招商局重庆交通科研设计院有限公司 | High-precision direct current power distribution system insulation resistance monitoring circuit, detection device and monitoring method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113608028A (en) * | 2021-09-02 | 2021-11-05 | 招商局重庆交通科研设计院有限公司 | High-precision direct current power distribution system insulation resistance monitoring circuit, detection device and monitoring method |
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