CN203688638U - Device for detecting resistive leakage current of metal oxide lightning arrester - Google Patents

Device for detecting resistive leakage current of metal oxide lightning arrester Download PDF

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Publication number
CN203688638U
CN203688638U CN201420047191.2U CN201420047191U CN203688638U CN 203688638 U CN203688638 U CN 203688638U CN 201420047191 U CN201420047191 U CN 201420047191U CN 203688638 U CN203688638 U CN 203688638U
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phase
module
automatic gain
gain control
control module
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CN201420047191.2U
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Inventor
朱震武
杨俊宏
花郁莹
兰马
皇甫德志
张云伟
刘珍山
许广芸
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Qujing Power Supply Bureau Of Yunnan Power Grid Corp
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Qujing Power Supply Bureau Of Yunnan Power Grid Corp
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Abstract

The utility model discloses a device for detecting resistive leakage current of a metal oxide lightning arrester, which comprises an I/V conversion module, an adder module, a resistive current detecting module, a phase discrimination module, a first optocoupler isolation module, a first phase shifting circuit, a first automatic gain control module, a second optocoupler isolation module, a second phase shifting circuit, a second automatic gain control module, a singlechip microcomputer and a display module, wherein the phase shifting circuits are used for carrying out phase shifting on capacitive current generated by a B-phase and an A-phase or a C-phase, the adder module is used for adding leakage current and the capacitive current after phase shifting of the A-phase or the C-phase, phase position discrimination is carried out on output results of the adder module and voltage signals extracted from the A-phase or the C-phase through the phase discrimination module, a discrimination result is inputted to the automatic gain control modules, and the automatic gain control modules adjusts the gain in real time, thereby eliminating alternative capacitive current interferences imposed on the A-phase or the C-phase.

Description

A kind of pick-up unit for metal oxide arrester resistive leakage current
Technical field
The utility model relates to a kind of pick-up unit for metal oxide arrester resistive leakage current.
Background technology
The leakage total current of lightning arrester has comprised capacitive leakage current and two parts of resistive leakage current.Wherein resistive leakage current is the technical parameter that really reflects lightning arrester running status.As shown in Figure 1, be the schematic equivalent circuit of metal oxide arrester, the circuit of a non-linear resistance and a Capacitance parallel connection, contains resistive component and capacitive component, that is: in the Leakage Current of metal oxide arrester but, in fact the lightning arrester of substation field is in one line, three-phase lightning protector both can bear this phase voltage, also because adjacent phase voltage can be by alternate stray capacitance to its generation effect, and then the leakage current that makes lightning arrester is with it independent one mutually compared with operation, produce variation, as shown in Figure 2 when existing lightning arrester resistance leakage circuit pick-up unit detects resistive leakage current, the leakage circuit all alternate stray capacitance not being produced carries out filtering, therefore detect the resistive leakage current obtaining inaccurate, can not truly reflect the running status of lightning arrester.
Summary of the invention
The utility model provides a kind of pick-up unit for metal oxide arrester resistive leakage current, and its object is, overcomes the not high problem of metal oxide arrester resistive leakage current pick-up unit accuracy of detection in prior art.
For a pick-up unit for metal oxide arrester resistive leakage current, comprise I/V modular converter 1, adder Module 2, current in resistance property detection module 3, phase demodulation module 4, the first light-coupled isolation module 5, the first phase-shift circuit 6, the first automatic gain control module 7, the second light-coupled isolation module 8, the second phase-shift circuit 9, the second automatic gain control module 10, single-chip microcomputer 11 and display module 12;
A phase or C phase lightning arrester straight-through current transformer are connected with the input end of I/V modular converter 1, the output terminal of the output terminal of described the first automatic gain control module 7, the output terminal of the second automatic gain control module 10 and I/V modular converter 1 is all connected with three input ends of adder Module 2, and output terminal, current in resistance property detection module 3, single-chip microcomputer 11 and the display module 12 of described adder Module 2 is connected successively;
The output terminal of described adder Module 2 is also connected with the input end of phase demodulation module 4;
The input end of described the first light-coupled isolation module 5 is connected with the voltage transformer (VT) TV of A phase or C phase lightning arrester, the output terminal of the first light-coupled isolation module 5 is connected with the input end of phase demodulation module 4 with the input end of the first phase-shift circuit 6, and described the first phase-shift circuit 6 is connected with the input end of the first automatic gain control module 7;
The input end of described the second light-coupled isolation module 8 is connected with the voltage transformer (VT) of B phase lightning arrester, and the second light-coupled isolation module 8, the second phase-shift circuit 9 and the second automatic gain control module 10 are connected successively;
The output terminal of described phase demodulation module 4 is connected with the input end of the second automatic gain control module 10 with the first automatic gain control module 7.
Described single-chip microcomputer is ARM LPC1114.
Described phase demodulation module is that RS triggers phase detector.
Described the first automatic gain control module and the second automatic gain control module are NE571 automatic gain controller.
Described adder Module adopts OP07 operational amplifier.
Described current in resistance property detection module is AD637 chip.
Described display module is ZTM480272S43-1WT liquid crystal display.
Beneficial effect
The utility model provides a kind of pick-up unit for metal oxide arrester resistive leakage current, comprises I/V modular converter 1, adder Module 2, current in resistance property detection module 3, phase demodulation module 4, the first light-coupled isolation module 5, the first phase-shift circuit 6, the first automatic gain control module 7, the second light-coupled isolation module 8, the second phase-shift circuit 9, the second automatic gain control module 10, single-chip microcomputer 11 and display module 12, the capacity current producing mutually by extracting the relative A phase of B or C, utilize phase-shift circuit to the capacity current phase shift of extracting, utilize adder Module that the capacity current after leakage current and the phase shift of A phase or C phase is added, by phase demodulation module, the Output rusults of adder Module and the voltage signal extracting mutually from A phase or C are carried out to phase judgment, differentiate result input automatic gain control module, automatic gain control module regulates gain size in real time, thereby eliminate the interference of the alternate capacity current that A phase or C be subject in mutually, utilize single-chip microcomputer to process with the capacity current in filtering A phase or C phase lightning arrester the capacity current in A phase or C phase lightning arrester, finally obtain current in resistance property accurately.
Brief description of the drawings
Fig. 1 is the schematic equivalent circuit of metal oxide arrester;
Fig. 2 is the schematic equivalent circuit that the alternate stray capacitance of metal oxide is disturbed;
Fig. 3 is structural representation of the present utility model;
Label declaration: 1-I/V modular converter, 2-adder Module, 3-current in resistance property detection module, 4-phase demodulation module, 5-the first light-coupled isolation module, 6-the first phase-shift circuit, 7-the first automatic gain control module, 8-the second light-coupled isolation module, 9-the second phase-shift circuit, 10-the second automatic gain control module, 11-single-chip microcomputer, 12-display module 12.
Embodiment
Below in conjunction with embodiment and accompanying drawing, the utility model is done further and explanation.
Example 1:
In this example, utilizing the utility model to detect A phase arrester resistance current detects, as shown in Figure 3, for structural representation of the present utility model, for a pick-up unit for metal oxide arrester resistive leakage current, comprise I/V modular converter 1, adder Module 2, current in resistance property detection module 3, phase demodulation module 4, the first light-coupled isolation module 5, the first phase-shift circuit 6, the first automatic gain control module 7, the second light-coupled isolation module 8, the second phase-shift circuit 9, the second automatic gain control module 10, single-chip microcomputer 11 and display module 12;
A phase or C phase lightning arrester straight-through current transformer are connected with the input end of I/V modular converter 1, the output terminal of the output terminal of described the first automatic gain control module 7, the output end group I/V modular converter 1 of the second automatic gain control module 10 is all connected with the input end of adder Module 2, and output terminal, current in resistance property detection module 3, single-chip microcomputer 11 and the display module 12 of described adder Module 2 is connected successively;
The output terminal of described adder Module 2 is also connected with the input end of phase demodulation module 4;
The input end of described the first light-coupled isolation module 5 is connected with the voltage transformer (VT) TV of A phase or C phase lightning arrester, the output terminal of the first light-coupled isolation module 5 is connected with the input end of phase demodulation module 4 with the input end of the first phase-shift circuit 6, and described the first phase-shift circuit 6 is connected with the input end of the first automatic gain control module 7;
The input end of described the second light-coupled isolation module 8 is connected with the voltage transformer (VT) of B phase lightning arrester, and the second light-coupled isolation module 8, the second phase-shift circuit 9 and the second automatic gain control module 10 are connected successively;
The output terminal of described phase demodulation module 4 is connected with the input end of the second automatic gain control module 10 with the first automatic gain control module 7.
Described single-chip microcomputer is ARM LPC1114.
Described phase demodulation module is that RS triggers phase detector.
Described the first automatic gain control module and the second automatic gain control module are NE571 automatic gain controller.
Described adder Module adopts OP07 operational amplifier.
Described current in resistance property detection module is AD637 chip.
Described display module is ZTM480272S43-1WT liquid crystal display.
The principle of work of this utility model is as follows:
The leakage current of an arrester sampling from core-theaded type TA be by composition, utilizes this device to weed out with retain
Utilize the first light-coupled isolation module to extract the first voltage signal from A phase TV, by the first voltage signal extracting by the first phase-shift circuit 6 phase shifts become with synchronous signal, outputs to adder Module 2 after then processing by the first automatic gain control module 7 again; Utilize the second light-coupled isolation module to extract second voltage signal from B phase TV simultaneously, by the second voltage signal extracting by the second phase-shift circuit 9 phase shifts become with synchronous signal, outputs to adder Module 2 after then processing by the second automatic gain control module 7 again;
Utilize I/V modular converter from core-theaded type TA, to extract convert tertiary voltage signal to, tertiary voltage signal inputs to adder Module 2, the Output rusults input phase demodulation module of adder Module 2, and the Output rusults of the first voltage signal and adder Module 2 is carried out phase demodulation comparison by phase demodulation module, if with all eliminate, both phase differential can be in error range so, if do not eliminate completely, output quantity in phase demodulation module 4 outputs in the first automatic gain control module 7 and the second automatic gain control module 10 as feedback so, regulate the yield value of the first automatic gain control module 7 and the second automatic gain control module 10, thereby reach elimination with object; Through single-chip microcomputer, current in resistance property detection module is detected after the signal obtaining is processed and eliminate the capacitive current component in lightning arrester, finally Output rusults is exported to display module 12 and show.
Principle explanation about this device:
At leakage current of an arrester in contain three components, taking A phase voltage as benchmark, with A phase voltage same-phase, for capacity current, therefore leading be that B phase voltage produces, owing to being capacitive, therefore 90 ° of the leading B phase voltages of its phase place, are 90 °, and 120 ° of B phase voltage hysteresis A phase voltages, therefore lag behind be-30 °.The object of this device is to eliminate in with component, therefore this device by the first phase-shift circuit 6 produce a phase place with differ the signal of 180 °, be the signal of-90 °; Again by the second phase-shift circuit 9 produce a phase place with differ the signal of 180 °, i.e. 150 ° of signals of phase place; Wherein the first automatic gain control module 7 is controlled output amplitude, the second automatic gain control module 10 is controlled output amplitude, the inverse value that this first automatic gain control module 7 and the second automatic gain control module 10 are exported with in adder Module 2, offset, adder Module is output as the result after counteracting, this result is outputed in phase demodulation module 4 and carries out phase bit comparison with A phase voltage, comparative result is exported to the first automatic gain control module 7 and the second automatic gain control module 10 as feedback signal, as its control signal.If also have the electric current of other interference, phase differential is just larger so, if only have phase differential will be in error range so.The result of processing after qualified detects by current in resistance property detection module 3, then shows by module 12 after being processed by ARM.

Claims (7)

1. the pick-up unit for metal oxide arrester resistive leakage current, it is characterized in that, comprise I/V modular converter (1), adder Module (2), current in resistance property detection module (3), phase demodulation module (4), the first light-coupled isolation module (5), the first phase-shift circuit (6), the first automatic gain control module (7), the second light-coupled isolation module (8), the second phase-shift circuit (9), the second automatic gain control module (10), single-chip microcomputer (11) and display module (12);
A phase or C phase lightning arrester straight-through current transformer are connected with the input end of I/V modular converter (1), the output terminal of the output terminal of described the first automatic gain control module (7), the output terminal of the second automatic gain control module (10) and I/V modular converter (1) is all connected with three input ends of adder Module (2), and output terminal, current in resistance property detection module (3), single-chip microcomputer (11) and the display module (12) of described adder Module (2) is connected successively;
The output terminal of described adder Module (2) is also connected with the input end of phase demodulation module (4);
The input end of described the first light-coupled isolation module (5) is connected with the voltage transformer (VT) (TV) of A phase or C phase lightning arrester, the output terminal of the first light-coupled isolation module (5) is connected with the input end of phase demodulation module (4) with the input end of the first phase-shift circuit (6), and described the first phase-shift circuit (6) is connected with the input end of the first automatic gain control module (7);
The input end of described the second light-coupled isolation module (8) is connected with the voltage transformer (VT) of B phase lightning arrester, and the second light-coupled isolation module (8), the second phase-shift circuit (9) and the second automatic gain control module (10) are connected successively;
The output terminal of described phase demodulation module (4) is connected with the input end of the second automatic gain control module (10) with the first automatic gain control module (7).
2. the pick-up unit for metal oxide arrester resistive leakage current according to claim 1, is characterized in that, described single-chip microcomputer is ARM LPC1114.
3. the pick-up unit for metal oxide arrester resistive leakage current according to claim 2, is characterized in that, described phase demodulation module is that RS triggers phase detector.
4. the pick-up unit for metal oxide arrester resistive leakage current according to claim 3, is characterized in that, described the first automatic gain control module and the second automatic gain control module are NE571 automatic gain controller.
5. the pick-up unit for metal oxide arrester resistive leakage current according to claim 4, is characterized in that, described adder Module adopts OP07 operational amplifier.
6. according to the pick-up unit for metal oxide arrester resistive leakage current described in claim 1-5 any one, it is characterized in that, described current in resistance property detection module is AD637 chip.
7. the pick-up unit for metal oxide arrester resistive leakage current according to claim 6, is characterized in that, described display module is ZTM480272S43-1WT liquid crystal display.
CN201420047191.2U 2014-01-24 2014-01-24 Device for detecting resistive leakage current of metal oxide lightning arrester Active CN203688638U (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104459280A (en) * 2014-12-19 2015-03-25 南京信息工程大学 Method for extracting resistance current of metal oxide arrester (MOA)
CN104931908A (en) * 2015-05-18 2015-09-23 国网上海市电力公司 Reference wave circuit for calibrating resistive current of lightning arrester
CN105911336A (en) * 2016-04-27 2016-08-31 国家电网公司 Bus leakage current detection apparatus
CN105911335A (en) * 2016-04-27 2016-08-31 国家电网公司 New type bus leakage current detection system
CN105954638A (en) * 2016-04-27 2016-09-21 国家电网公司 Busbar current leakage detection apparatus with input protection

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104459280A (en) * 2014-12-19 2015-03-25 南京信息工程大学 Method for extracting resistance current of metal oxide arrester (MOA)
CN104931908A (en) * 2015-05-18 2015-09-23 国网上海市电力公司 Reference wave circuit for calibrating resistive current of lightning arrester
CN105911336A (en) * 2016-04-27 2016-08-31 国家电网公司 Bus leakage current detection apparatus
CN105911335A (en) * 2016-04-27 2016-08-31 国家电网公司 New type bus leakage current detection system
CN105954638A (en) * 2016-04-27 2016-09-21 国家电网公司 Busbar current leakage detection apparatus with input protection

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