CN215770827U - Protection and metering integrated current transformer - Google Patents

Abstract

The utility model relates to the technical field of current transformers, and discloses a protection and metering integrated current transformer which comprises an iron chip, wherein the upper part and the lower part of the iron chip are respectively provided with a groove, a first winding is wound on the iron core above an upper end groove opening, a second winding is wound on one side surface of the iron chip along the groove edge of a lower end groove opening, the second winding is an annular winding, and the second winding is adhered to one side surface of the iron chip through a non-ferromagnetic circuit board. Compared with the prior art, the current transformer with the iron core and the Rogowski coil are combined to form the current transformer integrating protection and measurement, the current transformer with the closed iron core is used as a self-generating power supply, the Rogowski coil transformer is used for high-precision current sampling, the problem of magnetic saturation of the traditional current transformer is solved, the error is small during large-current measurement, and the protection precision is greatly improved.

Description

Protection and metering integrated current transformer

Technical Field

The utility model relates to the technical field of current transformers, in particular to a protection and metering integrated current transformer.

Background

Electronic transformer is one of the main equipment of operation real-time information digitization, in the circuit breaker trade, under the condition of getting the no voltage of electric side, guarantee to only rely on the electric current can make the product can normally work, at this moment just need have the current transformer (taking the magnetic core) of carrying the ability to provide the energy, traditional current transformer (taking the magnetic core) because there is magnetism, so there is magnetic protection, after the electric current increases to certain degree, the output just saturates, the electric current just can not increase again, just so lead to current transformer precision less in the measurement process.

The current electronic current transformer commonly used at present also comprises a current transformer based on a rogowski coil, wherein the rogowski coil is also called a current measuring coil and a differential current sensor, and is a novel electronic current transformer measuring device. Compared with the traditional mutual inductor with the iron core, the Rogowski coil current mutual inductor has the advantages of wide measuring range, no magnetic saturation, small volume and the like, does not contain ferromagnetic materials, has no hysteresis effect, and has almost zero phase error; there is no magnetic saturation image, so the measuring range can be from several amperes to hundreds of kiloamperes of electric current; the structure is simple, and no direct circuit connection exists between the current and the current to be measured, so that good electrical insulation is realized; the response frequency bandwidth is 0.1Hz-1 MHz.

Although the conventional rogowski coil electronic current transformer has obvious advantages compared with the conventional iron core type current transformer, along with the development of an intelligent power grid, the working of the conventional rogowski coil electronic current transformer puts higher requirements on the measurement sensitivity of the transformer, and the conventional rogowski coil and the conventional iron core type current transformer still need to be continuously improved and perfected.

SUMMERY OF THE UTILITY MODEL

Utility model purpose: aiming at the problems in the prior art, the utility model provides a protection and metering integrated current transformer, which combines the traditional current transformer with an iron core and a Rogowski coil current transformer.

The technical scheme is as follows: the utility model provides a protection and metering integrated current transformer which comprises an iron core sheet, wherein the upper part and the lower part of the iron core sheet are respectively provided with a groove, a first winding is wound on the iron core above an upper end notch, a second winding is wound on one side surface of the iron core sheet along the groove edge of a lower end notch, and the second winding is an annular winding.

Furthermore, the second winding is adhered to one side surface of the iron chip through a non-ferromagnetic circuit board.

Further, the first winding coil winding rule is 0.17 wire/990 Ts.

Further, the winding rule of the second winding is 0.06 wire/3370 Ts.

Further, current transformer still includes the casing, casing one side opening, its with lower extreme notch corresponds the position and sets up the open slot, current transformer set up in when in the casing, the lower extreme notch with the open slot is just right.

Further, the iron core plate is formed by laminating silicon steel sheets.

Has the advantages that:

1. the traditional current transformer with the iron core is combined with the Rogowski coil to form the current transformer integrating protection and metering, so that the problem of magnetic saturation of the traditional current transformer is solved, the error is small during large-current measurement, and the protection precision is greatly improved.

2. In the circuit breaker industry, under the condition that no voltage exists on the electricity taking side, a product can normally work only by current, and at the moment, a current transformer (with a magnetic core) with load capacity is needed to provide energy.

3. According to the test data of the current transformer in the specification, the current waveform sampled by the current transformer is complete, free of distortion and less in burrs. And the current high and low gears have no phase difference, the proportional relation is constant, the waveform linearity is good, and the deviation is within 0.5 percent.

Drawings

FIG. 1 is a schematic diagram of the overall structure of a current transformer according to the present invention;

FIG. 2 is a schematic structural view of three sets of current transformers of the present invention disposed in a housing;

fig. 3 is a waveform diagram of the current output of the current transformer of the present invention.

The winding comprises an iron chip 1, an upper end notch 2, a lower end notch 3, a first winding 4, a second winding 5, a circuit board 6, a shell 7 and an open slot 8.

Detailed Description

The utility model is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

The utility model discloses a protection and metering integrated current transformer, which is a double-coil transformer and is characterized in that a closed iron core current transformer is used as a self-generating power supply and a Rogowski coil transformer is used for high-precision current sampling according to different principles and characteristics of two coils, and the current transformer is shown in an attached figure 1. This current transformer includes iron core piece 1, and the groove is all seted up to 1 upper and lower parts of iron core piece, and it has first winding 4 to wind on the iron core of 2 tops of upper end notch, and 1 side of iron core piece has second winding 5 along the groove limit of lower extreme notch 3, and second winding 5 is annular winding. The iron core plate 1 of the present invention is formed by laminating silicon steel sheets.

The second winding 5 is adhered to one side surface of the iron core plate 1 through a non-ferromagnetic circuit board 6.

The winding rule of the first winding 4 is 0.17 line/990 Ts.

The winding rule of the second winding 5 is 0.06 wires/3370 Ts.

The first winding 4 with the iron core in the structure is a traditional current transformer with the iron core, and the lower end notch 3 corresponds to a Rogowski coil current transformer. This current transformer still sets up when using with casing 7 in, casing 7 one side opening, and it sets up open slot 8 with lower extreme notch 3 corresponding position, and when current transformer set up in casing 7, lower extreme notch 3 just to and open slot 8 is located lower extreme notch 3, and during the use, the wire directly passes open slot 8 on casing 7, has passed lower extreme notch 3 promptly, has just also passed second winding 5 in other words.

The first winding 4 and the second winding 5 are respectively provided with an outlet terminal which is connected with the main circuit. The first winding 4 is connected to a control board self-generating power circuit. When a current (ac) flows through the first winding 4 on the primary side, the winding can generate a corresponding induced current according to the magnitude of the current on the primary side. Here we can consider the first winding 4 as a constant current source with a variable current magnitude. Then, the alternating sine wave is converted into a half-wave signal with positive half cycle of pulsation through a rectification circuit. The current is then converted to a voltage by a voltage regulation circuit. The voltage grade of the voltage stabilizing circuit is monitored through the power supply monitoring chip, when the voltage grade exceeds the monitoring voltage, redundant voltage is released through the switch mos tube, otherwise, the switch mos tube is closed, and then stable direct-current voltage is output through the filter circuit. The second winding 5 is connected with a control board signal acquisition amplifying circuit. When there is a current (ac) across the second winding 5 on the primary side, the signal generated on the secondary side is the current differential with respect to time. The input current can be truly restored by a circuit which integrates the output voltage signal. The second winding 5 is firstly connected with an integral power supply, then passes through a filter circuit, filters high-frequency clutter to obtain a relatively clean sine wave, passes through a differential amplification circuit, sends a signal to a relatively proper voltage range, and is connected with an ADC port of a chip for sampling.

When the current transformers are used, three groups of current transformers are used together, and referring to fig. 2, the three groups of current transformers are mutually independent and respectively represent different phase lines. The wire passes through the lower end notch 3 of the current transformer.

The following is the test data of the current transformer of the utility model, and the following test data is to connect the coil into the intelligent residual current circuit breaker. Temperature: room temperature is 25 ℃; testing an instrument: KE9302 (three-phase low-voltage intelligent circuit breaker detection device), digital multimeter; precision: plus or minus 0.05 percent; test data: the intelligent residual current circuit breaker displays the value.

Table 1 shows the resistance values of the top and bottom transformers with magnetic cores according to the present invention

Table 2 shows the output values of the electrical parameters tested by the three groups of current transformers

Table 3 shows the current accuracy of the three current transformers of the present invention

Referring to fig. 3, the current output waveforms of 200A and 250A of the current transformer are shown, and as can be seen from the above table and fig. 3, the current waveforms are complete, distortion-free and have fewer burrs; the current high and low gears have no phase difference, and the proportional relation is constant; the waveform linearity is good, and the deviation is within 0.5%.

The above embodiments are merely illustrative of the technical concepts and features of the present invention, and the purpose of the embodiments is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to 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 within the protection scope of the present invention.

Claims (6)

1. The utility model provides a protection, measurement integral type current transformer, its characterized in that includes the iron core piece, the groove is all seted up to the upper and lower part of iron core piece, and the coiling has first winding on the iron core of upper end notch top, the groove limit of iron core piece side edge lower extreme notch has the second winding, the second winding is annular winding.

2. The integrated protection and metering current transformer of claim 1, wherein the second winding is attached to a side of the core sheet by a non-ferromagnetic circuit board.

3. The integrated protection and metering current transformer of claim 2, wherein the first winding coil is wound at a rule of 0.17 wires/990 Ts.

4. The integrated protection and metering current transformer of claim 2, wherein the second winding has a winding rule of 0.06 wires/3370 Ts.

5. The protection and metering integrated current transformer of claim 1, further comprising a housing, wherein an open slot is formed in a position of the housing, which corresponds to the lower end notch, on one side of the housing, and when the current transformer is disposed in the housing, the lower end notch is opposite to the open slot.

6. The integrated protection and metering current transformer of any one of claims 1 to 5, wherein the iron core sheet is laminated from silicon steel sheets.

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