CN212845610U - Low-voltage distribution network alternating current loop resistance tester - Google Patents
Low-voltage distribution network alternating current loop resistance tester Download PDFInfo
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- CN212845610U CN212845610U CN202021111726.XU CN202021111726U CN212845610U CN 212845610 U CN212845610 U CN 212845610U CN 202021111726 U CN202021111726 U CN 202021111726U CN 212845610 U CN212845610 U CN 212845610U
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Abstract
The utility model relates to the field of electric power, in particular to a resistance tester for an alternating current loop of a low-voltage distribution network, which comprises a constant current source for outputting stable detection current according to set current, wherein the output end of the constant current source is connected with a detected loop; the current detection circuit is connected with the tested loop and is used for detecting the current of the tested loop; the voltage detection circuit is connected with the tested loop and is used for detecting the voltage of the tested loop; the controller is connected with the current detection circuit and the voltage detection circuit and is used for adjusting the output stable detection current according to the detection current and the set current of the current detection circuit and calculating the loop resistance of the detected loop according to the voltage of the detected loop and the detection current output by the constant current source; the display module is connected with the controller and is used for displaying the loop resistance value calculated by the controller; and the communication module is connected with the controller and is used for transmitting the loop resistance value calculated by the controller. The utility model discloses realize improving the return circuit resistance measurement accuracy.
Description
Technical Field
The utility model relates to an electric power field especially relates to a low voltage distribution network alternating current loop resistance tester.
Background
The loop resistance testing system is suitable for testing the contact resistance value of the main contact of the high-low voltage switch, the direct current resistance value of the high-low voltage cable line and the like.
In a loop resistance test system, a controller controls a current source to output a stable current, and calculates a loop resistance by measuring voltages at both ends of a loop. However, the output of the current source is unstable, which may cause inaccurate calculation of the loop resistance.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem, the utility model provides a low voltage distribution network alternating current loop resistance tester to improve the degree of accuracy of loop resistance measurement.
Low voltage distribution network alternating current circuit resistance tester includes:
the constant current source is used for outputting stable detection current according to the set current, and the output end of the constant current source is connected with the detected loop;
the current detection circuit is connected with the tested loop and is used for detecting the current of the tested loop;
the voltage detection circuit is connected with the tested loop and is used for detecting the voltage of the tested loop;
the controller is connected with the current detection circuit and the voltage detection circuit and is used for adjusting the output stable detection current according to the detection current and the set current of the current detection circuit and calculating the loop resistance of the detected loop according to the voltage of the detected loop and the detection current output by the constant current source;
the display module is connected with the controller and is used for displaying the loop resistance value calculated by the controller;
and the communication module is connected with the controller and is used for transmitting the loop resistance value calculated by the controller.
Preferably, the constant current source comprises a constant current circuit, the constant current circuit comprises a voltage stabilizer U1 and resistors R1 and R2 which are sequentially connected to the output end of a voltage stabilizer U1, and the feedback port of the voltage stabilizer U1 is connected with the middle node of the resistors R1 and R2.
Preferably, the current detection circuit comprises a current detection amplifier U2, diodes D1 and D2 which are respectively connected between the RS + end and the RS-end of the current detection amplifier U2 in a positive and negative mode, a resistor R3 with one end connected with the RS-end of the current detection amplifier U2 and the other end connected with the common ground, and a resistor R4 with one end connected with the OUT end of the current detection amplifier U2 and the other end connected with the common ground.
Preferably, the current detection circuit further comprises a capacitor C1, one end of which is connected to the RS + end of the current detection amplifier U2, and the other end of which is connected to the common ground.
Preferably, the voltage detection circuit comprises an operational amplifier U3, a resistor R5 connected to the inverting input terminal of the operational amplifier U3, a resistor R6 connected to the output terminal of the operational amplifier U3, and a resistor R7 connected to the inverting input terminal of the operational amplifier U3 at one end and the output terminal of the resistor R6 at the other end.
Preferably, the voltage detection circuit further comprises a capacitor C2 having one end connected to the inverting input terminal of the operational amplifier U3 and the other end connected to the output terminal of the resistor R6.
Preferably, the voltage detection circuit further includes a capacitor C3 having one end connected to the output end of the R6 and the other end connected to the power supply terminal VCC, and a diode D3 having an anode connected to the output end of the R6 and a cathode connected to the power supply terminal VCC.
Preferably, the communication module comprises one or more of a 4G module, a 5G module, a Bluetooth module and a WIFI module.
The utility model has the advantages that:
1. outputting stable detection current through a constant current source so as to improve the measurement accuracy of the loop resistance, adjusting the output stable detection current according to the detection current and the set current of a current detection circuit, and improving the measurement accuracy of the loop resistance again;
2. the display module is connected with the controller, and when the controller calculates the resistance value of the loop resistor, the resistance value is sent to the display module to be displayed;
3. the communication module is used for transmitting the loop resistance value calculated by the controller. And the controller transmits the calculated loop resistance value to a server platform or an intelligent terminal of a tester and the like through the communication module.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
Fig. 1 is a schematic connection diagram of an ac loop resistance tester for a low-voltage distribution network according to an embodiment of the present invention;
fig. 2 is a schematic circuit diagram of a constant current source in an ac loop resistance tester of a low-voltage distribution network according to an embodiment of the present invention;
fig. 3 is a schematic circuit diagram of a current detection circuit in an ac loop resistance tester for a low-voltage distribution network according to an embodiment of the present invention;
fig. 4 is the embodiment of the utility model provides a voltage detection circuit's circuit schematic diagram in low voltage distribution network alternating current loop resistance tester.
Detailed Description
The technical solution of the present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited to these embodiments.
The embodiment of the utility model provides a low-voltage distribution network alternating current loop resistance tester, as shown in figure 1, include: the constant current source is used for outputting stable detection current according to the set current, and the output end of the constant current source is connected with the detected loop; the current detection circuit is connected with the tested loop and is used for detecting the current of the tested loop; the voltage detection circuit is connected with the tested loop and is used for detecting the voltage of the tested loop; the controller is connected with the current detection circuit and the voltage detection circuit and is used for adjusting the output stable detection current according to the detection current and the set current of the current detection circuit and calculating the loop resistance of the detected loop according to the voltage of the detected loop and the detection current output by the constant current source; the display module is connected with the controller and is used for displaying the loop resistance value calculated by the controller; and the communication module is connected with the controller and is used for transmitting the loop resistance value calculated by the controller.
The controller adjusts the output stable detection current according to the detection current of the current detection circuit and the set current, realizes the negative feedback of current detection through the detection current of the current detection circuit, and realizes the accuracy of current output of the constant current source, thereby improving the accuracy of loop resistance measurement.
The display module is connected with the controller, and when the controller calculates the resistance value of the loop resistor, the resistance value is sent to the display module to be displayed.
The communication module is used for transmitting the loop resistance value calculated by the controller. And the controller transmits the calculated loop resistance value to a server platform or an intelligent terminal of a tester and the like through the communication module. The communication module can be one or more of communication modules such as a 4G module, a 5G module, a Bluetooth module and a WIFI module.
In the present embodiment, as shown in fig. 2, the constant current source includes a constant current circuit, the constant current circuit includes a regulator U1 and resistors R1 and R2 connected to the output terminal of the regulator U1 in turn, and the feedback port of the regulator U1 is connected to the intermediate node of the resistors R1 and R2.
The constant current circuit is simple in structure, and only the voltage stabilizer U1 and 2 devices are needed for building the circuit. The voltage stabilizer U1 model is LM317, and LM317 is a variable output's integrated three terminal regulator, and the cooperation is just can realize constant current output with a resistance. The reference voltage difference of 1.25V is between the feedback port ADJ and the output port of the chip, and when the voltage difference is insufficient, the voltage stabilizing chip can increase the output voltage, so that the current of the load loop is increased until enough 1.25V voltage difference is generated on R1. It can also be considered that the voltage stabilization chip applies the voltage difference to the sampling resistor R1 to obtain a constant current. Considering that the current flowing into the ADJ terminal is small and can be ignored, the current on R1 is substantially equal to the current on R2. If an adjustable current source is needed, R1 can be replaced by a potentiometer, and the current value can be adjusted by adjusting the resistance value of the potentiometer.
In the present embodiment, as shown in fig. 3, the current detection circuit includes a current detection amplifier U2, diodes D1 and D2 connected in the positive and negative directions between the RS + terminal and the RS-terminal of the current detection amplifier U2, respectively, a resistor R3 having one end connected to the RS-terminal of the current detection amplifier U2 and the other end connected to a common ground, and a resistor R4 having one end connected to the OUT terminal of the current detection amplifier U2 and the other end connected to the common ground. The current detection circuit further comprises a capacitor C1, one end of which is connected with the RS + end of the current detection amplifier U2, and the other end of which is connected with the common ground.
The current detection amplifier U2 adopts MAX471MAX472 to realize I/V conversion, which can simplify the measurement of power supply current, can monitor high-end current, can be applied together with any power supply, has high built-in resistance precision, and can be used in association with current expansion.
In the present embodiment, as shown in fig. 4, the voltage detection circuit includes an operational amplifier U3, a resistor R5 connected to the inverting input terminal of the operational amplifier U3, a resistor R6 connected to the output terminal of the operational amplifier U3, and a resistor R7 having one end connected to the inverting input terminal of the operational amplifier U3 and the other end connected to the output terminal of the resistor R6. The voltage detection circuit further comprises a capacitor C2, one end of the capacitor C is connected with the inverting input end of the operational amplifier U3, and the other end of the capacitor C is connected with the output end of the resistor R6. The voltage detection circuit further comprises a capacitor C3 with one end connected with the output end of the R6 and the other end connected with the power supply end VCC, and a diode D3 with the anode connected with the cathode of the output end of the R6 and the power supply end VCC.
The operational amplifier U3 is an operational amplifier LM1458, the operational amplifier LM1458, a resistor R5, R6, R7 and a capacitor C2 form an inverting amplifier, the capacitor C2 is equivalent to low-pass filtering, a diode D3 is equivalent to clamping voltage which is smaller than Vcc +0.7v, the capacitor C3 and the operational amplifier form low-pass filtering, and in addition, the C3 is connected with the voltage Vcc to ensure that the input is high level when the power is on.
When the detection current of the current detection circuit is larger than the set current, reducing the stable detection current output by the constant current source until the detection current of the current detection circuit is equal to the set current; when the detection current of the current detection circuit is smaller than the set current, the stable detection current output by the constant current source is increased until the detection current of the current detection circuit is equal to the set current.
In this embodiment, the current output by the constant current source is adjusted to be equal to the set current, so as to improve the accuracy of the loop resistance measurement.
Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.
Claims (8)
1. Low voltage distribution network alternating current circuit resistance tester, its characterized in that includes:
the constant current source is used for outputting stable detection current according to the set current, and the output end of the constant current source is connected with the detected loop;
the current detection circuit is connected with the tested loop and is used for detecting the current of the tested loop;
the voltage detection circuit is connected with the tested loop and is used for detecting the voltage of the tested loop;
the controller is connected with the current detection circuit and the voltage detection circuit and is used for adjusting the output stable detection current according to the detection current and the set current of the current detection circuit and calculating the loop resistance of the detected loop according to the voltage of the detected loop and the detection current output by the constant current source;
the display module is connected with the controller and is used for displaying the loop resistance value calculated by the controller;
and the communication module is connected with the controller and is used for transmitting the loop resistance value calculated by the controller.
2. The alternating current loop resistance tester for the low-voltage distribution network of claim 1, wherein the constant current source comprises a constant current circuit, the constant current circuit comprises a voltage stabilizer U1 and resistors R1 and R2 which are sequentially connected to the output end of a voltage stabilizer U1, and a feedback port of the voltage stabilizer U1 is connected with the middle node of the resistors R1 and R2.
3. The resistance tester for the alternating-current loop of the low-voltage distribution network according to claim 1, wherein the current detection circuit comprises a current detection amplifier U2, diodes D1 and D2 which are respectively connected between the RS + end and the RS-end of the current detection amplifier U2 in a positive and negative mode, a resistor R3 with one end connected with the RS-end of the current detection amplifier U2 and the other end connected with the common ground, and a resistor R4 with one end connected with the OUT end of the current detection amplifier U2 and the other end connected with the common ground.
4. The AC loop resistance tester for low-voltage distribution network according to claim 3, wherein the current detection circuit further comprises a capacitor C1 having one end connected to RS + end of the current detection amplifier U2 and the other end connected to a common ground.
5. The resistance tester for the alternating-current loop of the low-voltage distribution network according to claim 1, wherein the voltage detection circuit comprises an operational amplifier U3, a resistor R5 connected to the inverting input end of the operational amplifier U3, a resistor R6 connected to the output end of the operational amplifier U3, and a resistor R7 connected to the inverting input end of the operational amplifier U3 at one end and the output end of the resistor R6 at the other end.
6. The AC loop resistance tester for the low-voltage distribution network according to claim 5, wherein the voltage detection circuit further comprises a capacitor C2 having one end connected to the inverting input terminal of the operational amplifier U3 and the other end connected to the output terminal of the resistor R6.
7. The AC loop resistance tester for low-voltage distribution network as claimed in claim 5, wherein said voltage detection circuit further comprises a capacitor C3 having one end connected to the output end of R6 and the other end connected to the power supply terminal VCC, and a diode D3 having its anode connected to the output end of R6 and its cathode connected to the power supply terminal VCC.
8. The low-voltage distribution network alternating-current loop resistance tester as claimed in claim 1, wherein the communication module comprises one or more of a 4G module, a 5G module, a Bluetooth module, and a WIFI module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202021111726.XU CN212845610U (en) | 2020-06-16 | 2020-06-16 | Low-voltage distribution network alternating current loop resistance tester |
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| CN202021111726.XU CN212845610U (en) | 2020-06-16 | 2020-06-16 | Low-voltage distribution network alternating current loop resistance tester |
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| CN212845610U true CN212845610U (en) | 2021-03-30 |
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| CN202021111726.XU Active CN212845610U (en) | 2020-06-16 | 2020-06-16 | Low-voltage distribution network alternating current loop resistance tester |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113917235A (en) * | 2021-10-19 | 2022-01-11 | 广东电网有限责任公司广州供电局 | Resistance comprehensive measurement system based on intelligent current-voltage clamp meter |
| WO2023197383A1 (en) * | 2022-04-11 | 2023-10-19 | 深圳市华星光电半导体显示技术有限公司 | Display system and display system detection method |
-
2020
- 2020-06-16 CN CN202021111726.XU patent/CN212845610U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113917235A (en) * | 2021-10-19 | 2022-01-11 | 广东电网有限责任公司广州供电局 | Resistance comprehensive measurement system based on intelligent current-voltage clamp meter |
| WO2023197383A1 (en) * | 2022-04-11 | 2023-10-19 | 深圳市华星光电半导体显示技术有限公司 | Display system and display system detection method |
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