CN2821591Y - DC insulation monitor line selector - Google Patents
DC insulation monitor line selector Download PDFInfo
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- CN2821591Y CN2821591Y CN 200520027084 CN200520027084U CN2821591Y CN 2821591 Y CN2821591 Y CN 2821591Y CN 200520027084 CN200520027084 CN 200520027084 CN 200520027084 U CN200520027084 U CN 200520027084U CN 2821591 Y CN2821591 Y CN 2821591Y
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Abstract
The utility model relates to a DC insulation monitoring line selector which belongs to the technical field of detection. The DC insulation monitoring line selector is used for solving the problem that the devices do not have anti-jamming performance. The utility model comprises a Hall sensor, a filter circuit, a signal conditioning circuit, an A/D converter, a CPU and a communication circuit, wherein the Hall sensor is arranged on a DC branch, and the signal output of the Hall sensor is connected with the filter circuit; the filter circuit is composed of an operational amplifier U1, an operational amplifier U2 and an operational amplifier U3; the signals of the Hall sensor are divided into two circuits, one circuit is connected with the inverting input end of the operational amplifier U1 through a resistor R1, the other circuit is connected with the non-inverting input end of the operational amplifier U2 through a capacitor C1, the output ends of the operational amplifier U1 and the operational amplifier U2 are respectively connected to the inverting input end of the operational amplifier U3 through a resistor R3 and a resistor R5, and the operational amplifier U3 outputs detection signals; the resistor R2 is a feedback resistor of the operational amplifier U1, and the resistor R2 has the same resistance with the resistor R1. The utility model can filter off various interferences with more than 1 Hz. The measuring accuracy is increased from +/-15% to +/-0.5%. The utility model also effectively suppresses transient signals.
Description
Technical field
The utility model relates to a kind of device that the DC circuit system is carried out malfunction monitoring, belongs to the detection technique field.
Background technology
In electric system, in order to give control, signal, protection, aut.eq., emergency lighting, direct current oil pump and to exchange power supply such as uninterrupted power supply(ups), requirement is provided with reliable direct supply in generating plant and the electric substation.These matching requirements direct supplys have high reliability and high stability, and the dielectric level of straight-flow system directly influences the reliability of DC loop, if 2 ground connection are taken place in the straight-flow system then may cause serious consequence.In order to monitor straight-flow system (comprising DC voltage and insulation status), require straight-flow system must be equipped with DC voltage insulating monitoring device.
At present, the straight-flow system insulating monitoring is realized by injecting low-frequency ac signal to straight-flow system.Because protection equipment is more and more in straight-flow system institute on-load, such as circuit Microcomputer Protection, tranformer protection, motor protection, switching protective device, or the like.These microcomputer protecting devices generally all will add filter capacitor at power input for avoiding interference.And the insulating monitoring equipment of AC signal is injected in above-mentioned employing, and it detects needed AC signal and can be absorbed by these electric capacity, causes insulating monitoring inaccurate; For this reason, the someone adopts the method for the signal of strengthening communication, but work can cause the protection misoperation like this, causes more major break down.The somebody adopts Hall element to monitor the direct current out-of-balance current, so as to reaching the purpose of straight-flow system insulating monitoring.This class device has overcome above-mentioned drawback, can carry out the straight-flow system insulating monitoring, but when if straight-flow system positive and negative insulation takes place reduces simultaneously, accident then can occur failing to report, still can cause dc system fault.In sum, vertiginous present situation makes existing insulating monitoring equipment more and more can not adapt to current actual conditions, is badly in need of the new alternate device of development.
Summary of the invention
Technical problem to be solved in the utility model provides a kind of detection sensitivity height, be not subjected to ectocine, can accurately detect the D.C. isolation supervision line selection apparatus of the arbitrary branch road generation of system under test (SUT) earth fault.
The technical scheme that addresses the above problem is:
A kind of D.C. isolation supervision line selection apparatus, it comprises Hall element 3, filtering circuit, signal conditioning circuit, A/D converter, CPU, show communicating circuit, wherein, Hall element 3 is installed on the load wire of monitored direct current branch, the signal output part of Hall element is connected with filtering circuit, filtering circuit and signal conditioning circuit, A/D converter, CPU, show that communicating circuit is electrically connected in proper order, described filtering circuit is by transport and placing device U1, U2, U3, capacitor C 1, C2, C3, resistance R 1～R7, potentiometer RW1～RW3 forms, the signal output part of Hall element 3 is divided into two paths of signals, one the tunnel connects the inverting input of transport and placing device U1 through resistance R 1, another road connects the in-phase input end of U2 through capacitor C 1, transport and placing device U1, the output terminal of U2 is respectively through resistance R 3, R5 connects the inverting input of transport and placing device U3, the output terminal of transport and placing device U3 is the output terminal of filtering circuit, resistance R 2 is the feedback resistance of transport and placing device U1, be connected between the output terminal and inverting input of transport and placing device resistance R 1, the resistance of R2 equates.
Above-mentioned D.C. isolation supervision line selection apparatus is respectively equipped with filter capacitor C2, C3 at the output terminal of transport and placing device U1, U3.
The utility model can be more than the elimination 1HZ after adopting filtering circuit various undesired signals, antijamming capability is enhanced.Simultaneously, measuring accuracy increases substantially, from set up before the filtering circuit ± 15% bring up to ± 0.5%.Adopt this filtering circuit that transient signals such as some virtual connections, impulse disturbances are effectively suppressed.The utility model reliable operation is a kind of desirable Novel DC insulating monitoring line selection apparatus.
Description of drawings
Fig. 1 is an electric theory diagram of the present utility model;
Fig. 2 is an electrical schematic diagram.
Mark is as follows among the figure: bus 1, load 2, Hall element 3, filtering circuit 4, signal conditioning circuit 5, A/D converter 6, CPU7, demonstration communicating circuit 8
Embodiment
In the straight-flow system of generating plant or transformer station, when the monitoring breakdown of conducting wires, various undesired signals can be sneaked into metering circuit between earth point and measurement point, wherein mainly be the undesired signal of 50HZ.For metering circuit, be with various undesired signal filterings under the distortionless situation of direct current signal.The employed various forms of wave filters of product, the trapper of the route selection of D.C. isolation supervision at present class all have its limitation, and the meeting that has causes the direct current signal decay, and the filtered band that has is narrower, and the circuit that has is very complicated.
Design philosophy of the present utility model be will sneak into the various interchange undesired signals of metering circuit carry out anti-phasely through phase inverters, superpose synchronously through the anti-phase undesired signal that exchanges again with not, and will exchange the undesired signal filtering.This method is simple, for the effectively filtering of interchange undesired signal of various frequencies, for the direct current monitor signal then without any influence.
As can be seen from Figure 1, the utility model is made up of Hall element 3, filtering circuit 4, signal conditioning circuit 5, A/D converter 6, CPU7, demonstration communicating circuit 8.Be connected to a plurality of load in parallel 2 on the monitored dc bus 1, Hall element 3 is installed on the load wire of monitored DC line, and it can convert current signal to voltage signal and deliver in this device.Signal conditioning circuit in the utility model is used for the simulating signal of input is carried out the conversion of amplitude or potential parameters, so that the next stage circuit can receive; The A/D change-over circuit is used for converting voltage analog to digital signal; CPU is used for the data of input are carried out computing or processing, and output correlation signal is used for demonstration, printing, communication etc.; Show that communicating circuit is used for the data-signal that CPU sends here is shown or passs by the data communication oral instructions accepting device in a distant place.
The filtering circuit 4 that Fig. 2 shows is made up of transport and placing device U1, U2, U3, capacitor C 1, C2, C3, resistance R 1～R7, potentiometer RW1～RW3.The signal output part of Hall element is connected with the input end of transport and placing device U1, U2 respectively, and different is that U1 is an inverting input, and U2 is an in-phase input end, and these two transport and placing devices are operated in different states.Output terminal at transport and placing device U1, U2 will produce the opposite alternating current output signal of phase place like this, and the output terminal of transport and placing device U1, U2 all connects the inverting input of transport and placing device U3, and the output terminal of transport and placing device U3 is the output terminal of filtering circuit.In foregoing circuit, transport and placing device U1 is a phase inverter, and transport and placing device U2 is the AC signal voltage follower, and transport and placing device U3 is the voltage inversion totalizer, and in the present embodiment, the model of transport and placing device U1, U2, U3 is OP-27.
In Fig. 2, capacitor C 1 is a capacitance, and it is connected between the in-phase input end of the signal output part of Hall element and transport and placing device U2, and resistance R 4 one terminates on the in-phase input end of transport and placing device U2, other end ground connection.For low-frequency interference signal, the capacitive reactance of capacitor C 1 can be approximated to be the interchange undesired signal and directly is added on the R4 R4=10M of present embodiment much smaller than resistance R 4.Resistance R 1 among Fig. 2, R2, R3, R5, R6 are substitutional resistance, and they and potentiometer RW1～RW3 are connected on respectively on the peripheral circuit of transport and placing device U1, U2, U3, and capacitor C 2, C3 equivalence are connected between the output terminal and ground of transport and placing device U1, U3.
The formation of signal conditioning circuit 5, A/D converter 6, CPU7, demonstration communicating circuit 8 is identical with existing like product in the utility model, repeats no more herein.
Claims (2)
1. a D.C. isolation is supervised line selection apparatus, it is characterized in that: it comprises Hall element [3], filtering circuit [4], signal conditioning circuit [5], A/D converter [6], CPU, show communicating circuit [8], wherein, Hall element [3] is installed on the load wire of monitored direct current branch, the signal output part of Hall element is connected with filtering circuit, filtering circuit and signal conditioning circuit, A/D converter, CPU, show that communicating circuit is electrically connected in proper order, described filtering circuit is by transport and placing device U1, U2, U3 forms, the signal output part of Hall element [3] is divided into two paths of signals, one the tunnel connects the inverting input of transport and placing device U1 through resistance R 1, another road connects the in-phase input end of U2 through capacitor C 1, transport and placing device U1, the output terminal of U2 is respectively through resistance R 3, R5 connects the inverting input of transport and placing device U3, the output terminal of transport and placing device U3 is the output terminal of filtering circuit, resistance R 2 is the feedback resistance of transport and placing device U1, be connected between the output terminal and inverting input of transport and placing device resistance R 1, the resistance of R2 equates.
2. D.C. isolation supervision line selection apparatus according to claim 1, it is characterized in that: the output terminal at transport and placing device U1, U3 is respectively equipped with filter capacitor C2, C3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520027084 CN2821591Y (en) | 2005-08-22 | 2005-08-22 | DC insulation monitor line selector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200520027084 CN2821591Y (en) | 2005-08-22 | 2005-08-22 | DC insulation monitor line selector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2821591Y true CN2821591Y (en) | 2006-09-27 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200520027084 Expired - Fee Related CN2821591Y (en) | 2005-08-22 | 2005-08-22 | DC insulation monitor line selector |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2821591Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107894558A (en) * | 2017-11-21 | 2018-04-10 | 合肥同智机电控制技术有限公司 | A kind of HVDC branch insulation detects circuit |
-
2005
- 2005-08-22 CN CN 200520027084 patent/CN2821591Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107894558A (en) * | 2017-11-21 | 2018-04-10 | 合肥同智机电控制技术有限公司 | A kind of HVDC branch insulation detects circuit |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |