CN211929278U

CN211929278U - Filter circuit of current transformer

Info

Publication number: CN211929278U
Application number: CN202021049701.1U
Authority: CN
Inventors: 李贵权
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-06-09
Filing date: 2020-06-09
Publication date: 2020-11-13
Anticipated expiration: 2030-06-09

Abstract

The utility model discloses a current transformer's filter circuit, including load L, mutual-inductor CT, filter circuit, mutual-inductor CT's wiring end is parallelly connected with load L, filter circuit is including triode Q, resistance R1, R2 and electric capacity C1, C2, resistance R1, electric capacity C1 establish ties and form the switch branch road, the switch branch road establish ties in triode Q's base, resistance R2, electric capacity C2 connect in parallel in triode Q's collecting electrode, electric capacity C2 one end connects triode Q's collecting electrode, other end ground connection, resistance R2 one end connect triode Q's collecting electrode, other end are established ties resistance R1 and/or electric capacity C1, mutual-inductor CT's wiring end with triode Q's projecting pole, switch branch road are connected.

Description

Filter circuit of current transformer

Technical Field

The utility model relates to a technical field such as instrument and equipment, current transformer, filter circuit, concretely relates to current transformer's filter circuit.

Background

The mutual inductor is also called instrument transformer, and is a general name of current mutual inductor and voltage mutual inductor. The high voltage can be changed into low voltage, and the large current can be changed into small current for measuring or protecting the system. Its function is mainly to convert high voltage or large current into standard low voltage (100V) or standard small current (5A or 1A, both referring to rated value) in proportion so as to realize standardization and miniaturization of measuring instrument, protection equipment and automatic control equipment. Meanwhile, the mutual inductor can be used for isolating a high-voltage system so as to ensure the safety of people and equipment.

The current transformer is an instrument for converting a large primary side current into a small secondary side current according to the electromagnetic induction principle to measure, and consists of a closed iron core and a winding, wherein the primary side winding has few turns and is connected in a circuit of the current to be measured in series. The current transformer generates a plurality of errors in the operation process, wherein most of the errors are generated by alternating excitation current for providing magnetic flux, but a small part of the errors are caused by hardware.

SUMMERY OF THE UTILITY MODEL

To the defect among the prior art, the utility model provides a current transformer's filter circuit to improve filtering ability, reduce measuring error.

The utility model provides a current transformer's filter circuit, includes load L, mutual-inductor CT, filter circuit, mutual-inductor CT's wiring end and load L are parallelly connected, filter circuit is including triode Q, resistance R1, R2 and electric capacity C1, C2, resistance R1, electric capacity C1 establish ties and form the switch branch road, the switch branch road establish ties in triode Q's base, resistance R2, electric capacity C2 connect in parallel in triode Q's collecting electrode, an end of electric capacity C2 connects triode Q's collecting electrode, other end ground connection, resistance R2 termination triode Q's collecting electrode, other end are established ties resistance R1 and/or electric capacity C1, mutual-inductor CT's wiring end with triode Q's projecting pole, switch branch road connect.

The utility model relates to a filter circuit of current transformer reduces the error that current transformer produced in the operation process through filter circuit, the switch branch can detect AC excitation current, and open filter circuit automatically according to AC excitation current's influence degree and realize the filtering function, for example, the current transformer produces AC excitation current in the operation process because misoperation or measured line oscillation lead to in the current transformer return circuit, but when AC excitation current is too little and do not influence the measuring instrument, resistance R1 set up can block the conduction that the triode Q was opened to less current, when AC excitation current is enough big, triode Q switches on, export AC excitation current through ground connection, thereby reduce the influence of oscillation to current transformer, reduce instrument measuring error, compare with current no difference filter circuit, through triode Q and switch branch to the isolation of weaker circuit, unnecessary energy loss is prevented, errors can be further reduced, the filtering capability of the normally closed filtering circuit can be influenced after the normally closed filtering circuit runs for a long time, and cost can be effectively reduced according to the size of disturbed flow.

Furthermore, one end of a resistor R1 of the switch branch is connected with the base of the triode Q, the other end of the resistor R1 is connected with a capacitor C1, one end of the capacitor C1 is connected with the resistor R1, and the other end of the capacitor C1 is connected with the terminal of the transformer CT and the resistor R2.

Further, the emitter of the transistor Q, the capacitor C1 and the resistor R2 are all connected to the same terminal.

Furthermore, in order to increase the structural strength, the filter circuit of the current transformer further comprises an insulating shell, and the insulating shell is sleeved outside the transformer CT.

Further, the terminal is connected to the insulating housing.

Further, the sensitivity of the switching branch response is improved, and the resistance value of the resistor R1 is smaller than that of the resistor R2.

Further, the capacitance values of the capacitors C1 and C2 are the same.

Further, the triode Q is a PNP type triode.

The beneficial effects of the utility model are embodied in:

the utility model relates to a filter circuit of current transformer, improve the filtering ability, reduce the measurement error; reduce the influence of oscillation to current transformer, reduce instrument measuring error, compare in current undifferentiated filter circuit, keep apart to weaker circuit through triode Q and switch branch road, prevent unnecessary energy loss, can further reduce the error, the filter circuit of normal close long-time running also can influence its filtering capability, distinguishes according to the size of vortex and can effectually reduce the cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below. Throughout the drawings, like elements or portions are generally identified by like reference numerals. In the drawings, elements or portions are not necessarily drawn to scale.

Fig. 1 is a schematic structural view of the exterior of the present invention;

fig. 2 is a schematic structural diagram of the filter circuit of the present invention.

In the figure, 1 is an insulating shell and 2 is a connector lug.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.

It is to be noted that unless otherwise specified, technical or scientific terms used herein shall have the ordinary meaning as understood by those skilled in the art to which the present invention belongs.

Examples

As shown in fig. 1-2:

In this embodiment, one end of the resistor R1 of the switching branch is connected to the base of the transistor Q, the other end of the resistor R1 is connected to the capacitor C1, one end of the capacitor C1 is connected to the resistor R1, and the other end of the capacitor C1 is connected to the terminal of the transformer CT and the resistor R2.

In this embodiment, the emitter of the transistor Q, the capacitor C1 and the resistor R2 are all connected to the same terminal.

As shown in fig. 2, in this embodiment, in order to increase the structural strength, the filter circuit of the current transformer further includes an insulating housing 1, and the insulating housing 1 is sleeved on the outer side of the transformer CT. The wiring head 2 is arranged outside the insulating shell 1, and the wiring ends of the mutual inductors CT are connected in the wiring head 2.

In the present embodiment, the terminal is attached to the insulating housing 1.

In this embodiment, the resistance of the resistor R1 is smaller than the resistance of the resistor R2.

In this embodiment, the capacitances of the capacitors C1 and C2 are the same.

In this embodiment, the transistor Q is a PNP transistor.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the scope of the embodiments of the present invention, and are intended to be covered by the claims and the specification.

Claims

1. The utility model provides a filter circuit of current transformer which characterized in that: including load L, mutual-inductor CT, filter circuit, mutual-inductor CT's wiring end and load L are parallelly connected, filter circuit is including triode Q, resistance R1, R2 and electric capacity C1, C2, resistance R1, electric capacity C1 establish ties and form the switch branch road, the switch branch road establish ties in triode Q's base, resistance R2, electric capacity C2 connect in parallel in triode Q's collecting electrode, electric capacity C2 one end connect triode Q's collecting electrode, other end ground connection, resistance R2 one end connect triode Q's collecting electrode, other end are established ties resistance R1 and/or electric capacity C1, mutual-inductor CT's wiring end with triode Q's projecting pole, switch branch road connect.

2. The filter circuit of a current transformer according to claim 1, wherein: one end of a resistor R1 of the switch branch is connected with the base electrode of the triode Q, the other end of the resistor R1 of the switch branch is connected with a capacitor C1, one end of a capacitor C1 is connected with a resistor R1, and the other end of the capacitor C1 is connected with a terminal of the mutual inductor CT and the resistor R2.

3. The filter circuit of a current transformer according to claim 1, wherein: the emitter of the transistor Q, the capacitor C1 and the resistor R2 are all connected to the same terminal.

4. The filter circuit of a current transformer according to claim 1, wherein: the transformer CT detection device is characterized by further comprising an insulating shell (1), wherein the insulating shell (1) is sleeved on the outer side of the transformer CT.

5. The filter circuit of a current transformer according to claim 4, wherein: the terminal is connected to the insulating housing (1).

6. The filter circuit of a current transformer according to claim 1, wherein: the resistance value of the resistor R1 is smaller than that of the resistor R2.

7. The filter circuit of a current transformer according to claim 1, wherein: the capacitance values of the capacitors C1 and C2 are consistent.

8. The filter circuit of a current transformer according to claim 1, wherein: the triode Q is a PNP type triode.