CN211263720U - Double-clamp-meter type direct current grounding searching instrument - Google Patents
Double-clamp-meter type direct current grounding searching instrument Download PDFInfo
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- CN211263720U CN211263720U CN201921404915.3U CN201921404915U CN211263720U CN 211263720 U CN211263720 U CN 211263720U CN 201921404915 U CN201921404915 U CN 201921404915U CN 211263720 U CN211263720 U CN 211263720U
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Abstract
The utility model discloses a double-clamp-meter type direct current grounding finder, which is used in a direct current power supply system, wherein the direct current power supply system comprises an insulation monitor, a bridge switcher and a current measurer; the positive connecting terminal, the negative connecting terminal and the grounding terminal of the bridge switcher are respectively connected to the positive electrode of the direct current bus, the negative electrode of the direct current bus and the grounding network; the current measurer comprises a measurer body, and a main clamp meter and an auxiliary clamp meter which are connected with the measurer body; the measurer body is provided with a display screen for displaying current waveforms detected by the main clamp meter and/or the auxiliary clamp meter. The current measurer of the double-clamp-meter direct-current grounding finder provided by the embodiment has the double clamp meters, namely the main clamp meter and the auxiliary clamp meter, so that the grounding conditions of the positive electrode and the negative electrode of the direct-current power supply system can be accurately measured under different state conditions, and the application range is wide.
Description
Technical Field
The utility model relates to a power equipment, concretely relates to two tong table formula direct current ground seeking appearance.
Background
The dc power supply system is a multi-branch network that supplies operating power to automation devices in a substation, such as protection, control, monitoring, and recording. Because the direct current system runs in a positive and negative non-grounding mode and a large distributed capacitance exists in the network, insulation damage can possibly become a source of secondary equipment malfunction. Therefore, when the insulation of the direct current system is reduced, the direct current system must be treated as soon as possible so as not to cause more accidents.
The direct current grounding finder used in the existing transformer substation is mostly based on the unbalanced bridge principle, and the device is composed of a bridge switcher and a current measurer. When the device is used, three terminals of the bridge switcher are respectively connected to the positive electrode of the direct current bus, the negative electrode of the direct current bus and the grounding network, the bridge switcher periodically grounds the direct current positive and negative buses through a large resistor respectively, if the direct current power supply system branch network generates positive electrode grounding, when the negative electrode of the bridge switcher is grounded, the positive electrode and the negative electrode form a loop through the grounding network, and a current measurer clamped on a positive branch can measure the current leakage at the moment; when the positive pole of the bridge switcher is grounded, the grounding point of the branch network cannot form a loop with the negative pole, and the current measurer cannot measure the leakage current. Because load current may exist in the dc power supply branch network, when the ground resistance is large or the load current is large, the load current is much larger than the leakage current, and when the bridge switch switches the ground bus, the current measurer clamped on the single-pole branch circuit is difficult to display the current leakage change at this time.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to overcome above-mentioned prior art not enough, provide a two tong table formula direct current ground connection seek appearance to under the state circumstances of difference, can both accurately measure DC power supply's positive negative pole ground connection condition.
In order to achieve the above purpose, the technical scheme of the utility model is that:
a double-clamp-meter type direct current grounding finder is used in a direct current power supply system, wherein the direct current power supply system comprises an insulation monitor, a bridge switcher and a current measurer;
the positive connecting terminal, the negative connecting terminal and the grounding terminal of the bridge switcher are respectively connected to the positive electrode of the direct current bus, the negative electrode of the direct current bus and the grounding network;
the current measurer comprises a measurer body, and a main clamp meter and an auxiliary clamp meter which are connected with the measurer body; the measurer body is provided with a display screen for displaying current waveforms detected by the main clamp meter and/or the auxiliary clamp meter.
Further, when the grounding branch and the polarity of the direct current power supply system are reported by the insulation monitor, the main clamp meter of the current measurer is clamped on the corresponding pole connection wire of the grounding branch, and if the waveform displayed by the current measurer is a square wave or a waveform close to the square wave, the grounding branch reported by the insulation monitor is correct.
Further, when the insulating monitor reports the grounding branch and the polarity of the dc power supply system, the main clamp meter of the current measurer is clamped on the corresponding pole connection of the grounding branch, if the display screen of the current measurer displays that the waveform is non-square wave and the main clamp meter can measure simultaneously and only measure the positive and negative pole currents of the grounding branch, the main clamp meter of the current measurer is clamped on the positive and negative pole connections of the grounding branch simultaneously to judge the grounding condition according to the waveform displayed by the current measurer, and if the waveform displayed by the current measurer is square wave or close to square wave, the grounding branch reported by the insulating monitor is correct.
Further, when the insulating monitor reports the grounding branch and the polarity of the dc power supply system, the main clamp meter of the current measurer is clamped on the corresponding pole connection of the grounding branch, if the display screen of the current measurer displays that the waveform is non-square wave and the main clamp meter cannot measure simultaneously and only measure the positive and negative pole currents of the grounding branch, the main clamp meter of the current measurer is clamped on the corresponding pole connection of the grounding branch, the auxiliary clamp meter clamps the opposite pole connection of the grounding branch to judge the grounding condition according to the waveform displayed by the current measurer, and if the waveform displayed by the current measurer is square wave or close to square wave, the grounding branch reported by the insulating monitor is correct.
Compared with the prior art, the utility model, its beneficial effect lies in:
the current measurer of the double-clamp-meter direct-current grounding finder provided by the embodiment has the double clamp meters, namely the main clamp meter and the auxiliary clamp meter, so that the grounding conditions of the positive electrode and the negative electrode of the direct-current power supply system can be accurately measured under different state conditions, and the application range is wide.
Drawings
Fig. 1 is a schematic view showing a first usage state of a dual-clamp-meter type dc ground finder provided in an embodiment of the present invention;
fig. 2 is a schematic view of a second usage state of the dual-clamp-meter type dc ground finder provided in the embodiment of the present invention;
fig. 3 is a schematic view showing a third usage state of the dual-clamp-meter type dc ground finder provided in the embodiment of the present invention;
in the figure: 1. a bridge switcher; 2. a current measurer; 21. a measurer body; 22. a master clamp meter; 23. and a secondary clamp meter.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
The appearance is seeked to two clamp table formula direct current ground connection that this embodiment provided for among the direct current power supply system, this direct current power supply system includes insulating monitor, because this insulating monitor is direct current power supply system's corollary equipment, and it can judge system ground connection condition and ground connection branch road according to busbar voltage and each branch road electric current size, because insulating monitor is conventional prior art, no longer gives unnecessary here to its structural configuration and theory of operation repeated.
The double-clamp-meter type direct current grounding finder comprises a bridge switcher 1 and a current measurer 2; the positive terminal, the negative terminal and the grounding terminal of the bridge switcher 1 are respectively connected to the positive pole of the direct current bus, the negative pole of the direct current bus and the grounding network; the current measuring device 2 includes a measuring device body 21, and a main clamp table 22 and an auxiliary clamp table 23 connected to the measuring device body 21; the measurer body 21 is provided with a display screen 210 for displaying the current waveform detected by the main clamp meter 22 and/or the auxiliary clamp meter 23, and if the current measurer 2 displays that the waveform is a square wave or a nearly square wave, it indicates that the branch clamped by the main clamp meter and/or the auxiliary clamp meter is grounded, and the specific principle is as follows:
when searching for direct current grounding, firstly, three terminals of the bridge switcher 1 are respectively connected with the anode of a direct current bus, the cathode of the direct current bus and a grounding network, according to a grounding branch circuit and polarity reported by an insulation monitor, a main clamp meter clamp 22 of a current measurer 2 is arranged on a corresponding pole connection of the branch circuit, if the current measurer 2 displays that the waveform is a square wave or is close to the square wave, grounding of the branch circuit can be determined, the result of the insulation monitor is verified to be correct, the possibility of false alarm grounding is eliminated, the next-stage branch circuit of the branch circuit is continuously searched, and the using mode of the current measurer under the condition is shown as the attached condition 1: that is, the grounding situation is judged based on the waveform displayed by the current measuring instrument by using only the current measuring instrument main clamp 22 to hold the grounding branch corresponding pole connection without using the current measuring instrument sub clamp 23. The specific principle that the current measurer displays that the waveform is square wave or approximate square wave and can determine the grounding of the branch is as follows: assuming that the positive pole of the branch is grounded, when the bridge switch grounds the negative bus through a large resistor, the positive bus → the grounding branch grounding point → the grounding point of the bridge switch → the negative bus forms a loop, and a leakage current with a substantially constant magnitude flows in the loop; when the bridge switcher grounds the positive bus through the large resistor, a loop cannot be formed between the positive bus and the negative bus through the grounding point, and no leakage current exists in the branch circuit; during one switching period of the bridge switch, the leakage current flowing in the grounding branch only has a half period, and the current waveform is square wave or close to square wave.
If the current measurer 2 shows that the waveform has a larger difference with the square wave, it indicates that the load current of the branch is much larger than the leakage current or the branch is not grounded, at this time, if the wiring interval of the positive and negative branches is close, the clamp meter can avoid other non-grounded branches during measurement, the main clamp meter can simultaneously measure and only measure the positive and negative currents of the branch, the main clamp meter is used to simultaneously measure the positive and negative currents of the branch to eliminate the influence of the load current on the leakage current, thereby judging whether the branch is grounded, in this case, the use mode of the current measurer is as shown in the attached figure case 2: the method is characterized in that a current measurer auxiliary clamp meter 23 is not used, only a current measurer main clamp meter 22 is used for clamping the positive and negative electrode wires of the grounding branch at the same time, the grounding condition is judged according to the waveform displayed by the current measurer, if the current waveform is a square wave or is close to the square wave, the grounding branch reported by the insulation monitor can be determined to be correct, the branch is indeed grounded, and if the current waveform has a far difference with the square wave, the grounding of the branch can be basically excluded.
If the current measurer shows that the difference between the waveform and the square wave is large, field wiring is closely staggered or the connection interval between the positive electrode and the negative electrode of the same branch is far, the main clamp meter can not measure the current of the positive electrode and the negative electrode of the branch at the same time and only can measure the current of the positive electrode and the negative electrode of the branch, the current of the main clamp meter is used for measuring the current of the grounding electrode, the current of the auxiliary clamp meter is negated after the absolute value of the current of the main clamp meter is taken in the current measurer and then is superposed with the absolute value of the current of the main clamp meter to offset the load current, the leakage current is displayed on the current measurer, whether the branch is grounded or: the grounding condition is judged according to the waveform displayed by the current measurer 2 by using the main clamp meter 22 to clamp the grounding electrode connection and the auxiliary clamp meter 23 to clamp the opposite electrode connection, if the current waveform is a square wave or a close square wave, the grounding branch reported by the insulation monitor can be determined to be correct, the branch is indeed grounded, and if the current waveform has a far difference with the square wave, the grounding of the branch can be basically excluded.
Therefore, the current measurer of the double-clamp-meter type direct current grounding finder provided by the embodiment has the double clamp meters, namely the main clamp meter and the auxiliary clamp meter, so that the grounding conditions of the positive electrode and the negative electrode of the direct current power supply system can be accurately measured under different states, and the application range is wide.
The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention, which cannot limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.
Claims (4)
1. A double-clamp-meter type direct current grounding finder is used in a direct current power supply system, wherein the direct current power supply system comprises an insulation monitor, and is characterized by comprising a bridge switcher and a current measurer;
the positive connecting terminal, the negative connecting terminal and the grounding terminal of the bridge switcher are respectively connected to the positive electrode of the direct current bus, the negative electrode of the direct current bus and the grounding network;
the current measurer comprises a measurer body, and a main clamp meter and an auxiliary clamp meter which are connected with the measurer body; the measurer body is provided with a display screen for displaying current waveforms detected by the main clamp meter and/or the auxiliary clamp meter.
2. The dual-clamp dc ground finder of claim 1, wherein when the insulation monitor reports the grounding branch and polarity of the dc power system, the main clamp of the current measurer is clamped on the corresponding pole connection of the grounding branch, and if the waveform displayed by the current measurer is square wave or close to square wave, it indicates that the grounding branch reported by the insulation monitor is correct.
3. The dual-clamp dc ground finder of claim 1, wherein when the insulation monitor reports the grounding branch and polarity of the dc power system, the main clamp of the current measurer is clamped to the corresponding pole connection of the grounding branch, if the display of the current measurer shows that the waveform is non-square wave and the main clamp can measure simultaneously and only measure the positive and negative pole currents of the grounding branch, the main clamp of the current measurer is clamped to the positive and negative pole connections of the grounding branch simultaneously to determine the grounding condition according to the waveform displayed by the current measurer, and if the waveform displayed by the current measurer is square wave or close to square wave, it indicates that the grounding branch reported by the insulation monitor is correct.
4. The dual-clamp dc ground finder of claim 1, wherein when the insulation monitor reports the ground branch and the polarity of the dc power system, the main clamp of the current measurer is clamped to the corresponding pole connection of the ground branch, if the display of the current measurer shows that the waveform is non-square wave and the main clamp cannot measure simultaneously and only measure the positive and negative pole currents of the ground branch, the main clamp of the current measurer is clamped to the corresponding pole connection of the ground branch, and the auxiliary clamp is clamped to the corresponding pole connection of the ground branch to determine the grounding condition according to the waveform displayed by the current measurer, and if the waveform displayed by the current measurer is square wave or close to square wave, the grounding branch reported by the insulation monitor is correct.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921404915.3U CN211263720U (en) | 2019-08-27 | 2019-08-27 | Double-clamp-meter type direct current grounding searching instrument |
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| CN201921404915.3U CN211263720U (en) | 2019-08-27 | 2019-08-27 | Double-clamp-meter type direct current grounding searching instrument |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110412399A (en) * | 2019-08-27 | 2019-11-05 | 中国南方电网有限责任公司超高压输电公司天生桥局 | A kind of double split-core type meter formula DC earthing searching instruments |
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2019
- 2019-08-27 CN CN201921404915.3U patent/CN211263720U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110412399A (en) * | 2019-08-27 | 2019-11-05 | 中国南方电网有限责任公司超高压输电公司天生桥局 | A kind of double split-core type meter formula DC earthing searching instruments |
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