CN214750560U - Transformer short-circuit impedance live detection device - Google Patents
Transformer short-circuit impedance live detection device Download PDFInfo
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- CN214750560U CN214750560U CN202121005199.9U CN202121005199U CN214750560U CN 214750560 U CN214750560 U CN 214750560U CN 202121005199 U CN202121005199 U CN 202121005199U CN 214750560 U CN214750560 U CN 214750560U
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- 238000001514 detection method Methods 0.000 title claims abstract description 14
- 238000005070 sampling Methods 0.000 claims description 6
- 239000003990 capacitor Substances 0.000 claims description 3
- 230000008030 elimination Effects 0.000 abstract 1
- 238000003379 elimination reaction Methods 0.000 abstract 1
- 238000005259 measurement Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000001052 transient effect Effects 0.000 description 1
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Abstract
The utility model provides a transformer short circuit impedance live detection device, which comprises a voltage signal circuit and a current signal circuit, wherein the voltage signal circuit comprises a micro voltage transformer, the input end is connected with the secondary side of a power grid PT, and the output end is connected with the input end of a collection card; the current signal circuit comprises a micro current transformer and an operational amplifier OP07, wherein the input end of the operational amplifier is connected with the output end of the micro current transformer, the output end of the operational amplifier is connected with the input end of the acquisition card, and the non-inverting input end of the operational amplifier is grounded. The device can measure the complete voltage and current waveform in real time, and can realize the noise reduction and harmonic elimination of signals through a digital filter subsequently.
Description
Technical Field
The utility model relates to a power equipment detection area, more specifically relates to a transformer short circuit impedance live detection device.
Background
At present, the detection of the short-circuit impedance of the transformer is still mostly in a power failure condition, and under the condition of electrification, although the short-circuit impedance can be calculated through the existing measurement and control system of a power grid, the repeatability is poor and the precision is not high. The reason for this is that the waveform of the power grid in actual operation contains higher harmonics, the voltage amplitude is not stable enough, and the voltage and current data obtained by the power grid measurement and control device is an effective value in a sampling period and is not suitable for directly calculating the short-circuit impedance of the transformer.
Disclosure of Invention
The utility model discloses the purpose is guaranteeing not to influence under the prerequisite of electric power system equipment reliable operation, provides a voltage current sampling system for electrified detection of transformer short circuit impedance, can real-time measurement complete voltage current wave form, follow-up alright fall and eliminate the processing of harmonic with passing through digital filter to the signal realization.
The utility model discloses a realize above-mentioned purpose, realize through following technical scheme:
transformer short circuit impedance live detection device, its characterized in that includes voltage signal circuit and current signal circuit:
the voltage signal circuit comprises a micro voltage transformer, the input end of the micro voltage transformer is connected with the secondary side of a power grid PT, and the output end of the micro voltage transformer is connected with the input end of the acquisition card;
the current signal circuit comprises a micro current transformer and an operational amplifier OP07, wherein the input end of the operational amplifier is connected with the output end of the micro current transformer, the output end of the operational amplifier is connected with the input end of the acquisition card, and the non-inverting input end of the operational amplifier is grounded.
Preferably, the current signal circuit further comprises a pair of protection diodes connected in inverse parallel at the input end of the operational amplifier, and a sampling resistor connected in series between the output end of the operational amplifier and the ground.
Preferably, the power supply also comprises an AC-DC switching power supply module for supplying power to the operational amplifier OP07, wherein the input end of the switching power supply module is connected in series with a thermistor 5D-9 and connected with 220V mains supply, and is connected in parallel with a piezoresistor 10D 471K; the output end of the switching power supply is a +/-12V bipolar signal, and the output end of the switching power supply is connected with the electrolytic capacitor in parallel and then grounded.
Preferably, the device comprises six circuits of the voltage signal circuit and the current signal circuit.
The utility model has the advantages that:
1. when the transformer short-circuit impedance live detection is carried out, the circuit can stably run for a long time, does not influence a power grid, and can acquire complete voltage and current signal waveforms of the transformer in real time.
2. Because the miniature voltage current transformer works by relying on the electromagnetic induction principle, the electric isolation of the power grid and the whole detection device is realized, and the safe operation of the whole detection system can be fully ensured.
3. The current acquisition and conversion part uses an operational amplifier, and the virtual break characteristic of the operational amplifier is utilized to enable the current transformer to work in a zero-load state approximately, so that the measurement precision is high.
Drawings
Fig. 1 is a circuit diagram of a voltage signal in one path according to embodiment 1 of the present invention;
fig. 2 is a circuit diagram of an embodiment 2 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
A transformer short circuit impedance live detection device comprises a voltage signal circuit and a current signal circuit, wherein the voltage signal circuit and the current signal circuit are respectively provided with six circuits; as shown in figure 1, each voltage signal circuit consists of a 53.5V/2.5V miniature voltage transformer, the input end of the miniature voltage transformer is connected with the secondary side of a power grid PT, and the output end of the miniature voltage transformer is connected with the input end of an acquisition card.
As shown in fig. 2, each current signal circuit comprises a 5A/2.5mA micro current transformer, an operational amplifier OP07 and a sampling resistor, wherein the input end of the operational amplifier is connected with the output end of the micro current transformer, the output end of the operational amplifier is connected with the input end of the acquisition card, and the non-inverting input end of the operational amplifier is grounded; the two protection diodes are reversely connected in parallel with the input end of the operational amplifier, and the sampling resistor is connected between the output end of the operational amplifier and the ground in series.
An AC-DC switching power supply module supplies power to all the operational amplifiers OP07, the input end of the AC-DC switching power supply module is connected with 220V mains supply, and a thermistor 5D-9 is also connected in series in order to prevent the damage of surge current; in order to resist transient overvoltage in a power grid, a voltage dependent resistor 10D471K is connected in parallel at the input end; the output of the switching power supply is a +/-12V bipolar signal, and the output end of the switching power supply is connected with two 100uF electrolytic capacitors for filtering in parallel.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing embodiments, or equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. Transformer short circuit impedance live detection device, its characterized in that includes voltage signal circuit and current signal circuit:
the voltage signal circuit comprises a micro voltage transformer, the input end of the micro voltage transformer is connected with the secondary side of a power grid PT, and the output end of the micro voltage transformer is connected with the input end of the acquisition card;
the current signal circuit comprises a micro current transformer and an operational amplifier OP07, wherein the input end of the operational amplifier is connected with the output end of the micro current transformer, the output end of the operational amplifier is connected with the input end of the acquisition card, and the non-inverting input end of the operational amplifier is grounded.
2. The apparatus as claimed in claim 1, wherein the current signal circuit further comprises a pair of protection diodes connected in anti-parallel to the input of the operational amplifier, and a sampling resistor connected in series between the output of the operational amplifier and ground.
3. The transformer short-circuit impedance live detection device according to claim 2, further comprising an AC-DC switching power supply module for supplying power to the operational amplifier OP07, wherein an input end of the switching power supply module is connected in series with a thermistor 5D-9 and connected in parallel with 220V commercial power, and connected in parallel with a varistor 10D 471K; the output end of the switching power supply is a +/-12V bipolar signal, and the output end of the switching power supply is connected with the electrolytic capacitor in parallel and then grounded.
4. The apparatus as claimed in any one of claims 1 to 3, wherein six of said voltage signal circuits and said current signal circuits are included.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121005199.9U CN214750560U (en) | 2021-05-12 | 2021-05-12 | Transformer short-circuit impedance live detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121005199.9U CN214750560U (en) | 2021-05-12 | 2021-05-12 | Transformer short-circuit impedance live detection device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214750560U true CN214750560U (en) | 2021-11-16 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121005199.9U Active CN214750560U (en) | 2021-05-12 | 2021-05-12 | Transformer short-circuit impedance live detection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN214750560U (en) |
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2021
- 2021-05-12 CN CN202121005199.9U patent/CN214750560U/en active Active
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