CN214476920U

CN214476920U - Voltage type current transformer

Info

Publication number: CN214476920U
Application number: CN202120690879.2U
Authority: CN
Inventors: 刘付学聪
Original assignee: Guangdong Huimao Electricity Co ltd
Current assignee: Guangdong Huimao Electricity Co ltd
Priority date: 2021-04-06
Filing date: 2021-04-06
Publication date: 2021-10-22
Anticipated expiration: 2031-04-06

Abstract

The utility model discloses a voltage type current transformer in the field of electronics and electricity, which comprises a current transformer shell, wherein a protective shell is fixedly arranged on the front side of the current transformer shell, the front side of the current transformer shell is movably connected with a mutual inductor S1 terminal, the internal circuit of the current transformer is connected in series, namely, a primary winding is connected in series with a tested circuit, a secondary winding is connected in series with all instrument loads, a proper transformation ratio is selected according to the size of the tested current, otherwise, the error is increased, meanwhile, a secondary side mutual inductor S2 terminal is connected with a lead and grounded, so that once insulation is damaged, high voltage of a primary side is blown into a secondary low voltage side to cause personal and equipment accidents, secondary side open circuit can enable secondary side voltage to reach hundreds of volts, once the secondary side voltage is touched to cause electric shock accidents, then, power failure treatment is carried out, all rear sides can be reused, thereby avoiding secondary open circuit of the mutual inductor, the effect of potential safety hazard to equipment and people caused by high voltage is generated.

Description

Voltage type current transformer

Technical Field

The utility model relates to an electron electric field specifically is voltage type current transformer.

Background

In life, along with the development of the electronic and electrical field, the requirement of users for safety protection is increasingly outstanding, and in the aspect of electric protection, people mostly adopt a current transformer for safety protection, but the protection of a general current transformer has the following two disadvantages: high voltage appears more easily in the secondary of mutual-inductor opening a way, but also appears the electric shock accident more easily and the mutual-inductor can not long distance measurement, and the problem that the secondary load value exceeds the standard value can appear in long distance measurement, and long distance's measurement can make the impedance value grow moreover, and circuit voltage drop is great, produces certain influence to measurement accuracy.

In the prior art, the above problems are caused by human errors, animal biting of a wire, poor interface contact, instrument failure, and the like, which cause secondary open circuit of the transformer, so that a voltage type current transformer is provided by those skilled in the art to solve the above problems in the background art, and in order to avoid the secondary open circuit of the transformer, which causes potential safety hazards to equipment and people due to high voltage, and inaccurate measurement accuracy, those skilled in the art adopt voltage type measurement, and according to the characteristics that impedance of the voltmeter is very large, a secondary current value flowing through the voltmeter is very small, and the unknown characteristic can be almost ignored, so that the measurement accuracy is improved to a great extent, and the secondary load is reduced.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a voltage type current transformer to solve the problem that proposes among the above-mentioned background art. In order to achieve the above object, the utility model provides a following technical scheme: voltage type current transformer, including the current transformer shell, the positive fixed mounting of current transformer shell has the protecting crust, the positive swing joint of current transformer shell has mutual-inductor S1 terminal, the positive swing joint of current transformer shell has mutual-inductor S2 terminal, the bottom fixed mounting of current transformer shell has the supporting baseplate, the positive fixed mounting of current transformer shell has standard fixed value resistor, the joint groove has been seted up on the positive top of supporting baseplate.

As a further aspect of the present invention: the size and the shape of the transformer S1 terminal and the transformer S2 terminal are the same, the transformer S1 terminal is located at the right left side of the transformer S2 terminal, and in order to ensure that the contact conditions of the transformer S1 terminal and the transformer S2 terminal with a standard fixed value resistor are completely consistent.

As a further aspect of the present invention: the left side of the standard fixed value resistor is fixedly mounted with the outer wall of the transformer S2 terminal, and the right side of the standard fixed value resistor is fixedly mounted with the outer wall of the transformer S1 terminal, so that good contact of the transformer S1 terminal and the transformer S2 terminal with the standard fixed value resistor is facilitated.

As a further aspect of the present invention: the quantity in joint groove is two, is called left draw-in groove and right draw-in groove respectively, and left draw-in groove is located the left side of current transformer shell bottom, and right draw-in groove is located the right side of current transformer shell bottom, conveniently installs and the maintenance in later stage.

As a further aspect of the present invention: the inner wall fixed mounting of mutual-inductor S1 terminal has the wire, wire and voltmeter fixed connection, the inner wall fixed mounting of mutual-inductor S2 terminal has the earth connection, converts the current reading into with the voltmeter reading.

As a further aspect of the present invention: the front of protective housing has seted up the filling groove, the back and the front fixed connection of current transformer shell of protective housing guarantee the security of internal circuit, prolong voltage type current transformer's life.

Compared with the prior art, the beneficial effects of the utility model are that:

1. the utility model discloses in, carry out series connection through the internal line to current transformer, once winding promptly should be established ties with the circuit of being tested, and the secondary winding then establishes ties with all instrument loads, according to the measured current size, select suitable transformation ratio, otherwise the error will increase, and simultaneously, secondary side mutual-inductor S2 terminal connecting wire and ground connection, in case the protection insulation is damaged, the high pressure of primary side is scurried into the secondary low pressure side, cause people and equipment accident, secondary side open circuit can make secondary side voltage reach several hundred volts, in case touch will cause the electric shock accident, therefore, current transformer secondary side all is equipped with short circuit switch, prevent that secondary side opens a way, in the use, secondary side open circuit should remove the circuit load once opening a way at once, then, the processing of having a power failure, all good rear reuses, thereby reached and avoided mutual-inductor secondary to open a way, produce the high voltage and to equipment, The potential safety hazard to people is caused.

2. The utility model discloses in, through the safety protection to devices such as measuring instrument, relay protection, breaker failure judgement and fault filtering to all establish two to eight secondary winding's current transformer in return circuits such as generator, transformer, be qualified for the next round of competitions, generating line segmentation circuit breaker, generating line circuit breaker, bypass circuit breaker, to current transformer install the place and also should set up according to the unprotected area that eliminates main protection device as far as possible, thereby reached and carried out accurate measuring effect to the mutual-inductor.

Drawings

Fig. 1 is a front view of the present invention;

fig. 2 is a cross-sectional view of the current transformer case of the present invention;

fig. 3 is a perspective view of the middle supporting bottom plate of the present invention;

fig. 4 is a circuit diagram of the present invention.

In the figure: 1. a current transformer housing; 2. a protective shell; 3. transformer S1 terminals; 4. transformer S2 terminals; 5. a support base plate; 6. a standard fixed value resistor; 7. a clamping groove.

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.

Referring to fig. 1-4, in the embodiment of the present invention, a voltage type current transformer includes a current transformer housing 1, a protective shell 2 is fixedly installed on a front side of the current transformer housing 1, a filling groove is opened on the front side of the protective shell 2, a back side of the protective shell 2 is fixedly connected to the front side of the current transformer housing 1, so as to ensure safety of internal circuits and prolong service life of the voltage type current transformer, a transformer S1 terminal 3 is movably connected to the front side of the current transformer housing 1, a lead is fixedly installed on an inner wall of the transformer S1 terminal 3, the lead is fixedly connected to a voltmeter, a ground lead is fixedly installed on an inner wall of the transformer S2 terminal 4, reading of the voltmeter is converted into current reading, the size and shape of the transformer S1 terminal 3 and the transformer S2 terminal 4 are the same, the transformer S1 terminal 3 is located on a right left side of the transformer S2 terminal 4, in order to ensure that the contact conditions of the terminal 3 of the mutual inductor S1 and the terminal 4 of the mutual inductor S2 are completely consistent with those of the standard fixed value resistor 6, the front surface of the shell 1 of the current mutual inductor is movably connected with the terminal 4 of the mutual inductor S2, the bottom end of the shell 1 of the current mutual inductor is fixedly provided with a supporting bottom plate 5, the front surface of the shell 1 of the current mutual inductor is fixedly provided with the standard fixed value resistor 6, the left side of the standard fixed value resistor 6 is fixedly arranged with the outer wall of the terminal 4 of the mutual inductor S2, the right side of the standard fixed value resistor 6 is fixedly arranged with the outer wall of the terminal 3 of the mutual inductor S1, so that the good contact between the terminal 3 of the mutual inductor S1 and the terminal 4 of the mutual inductor S2 and the standard fixed value resistor 6 is facilitated, the top end of the front surface of the supporting bottom plate 5 is provided with two clamping grooves 7 which are respectively called as a left clamping groove and a right clamping groove, the left clamping groove is positioned at the left side of the bottom end of the shell 1 of the current mutual inductor, the right clamping groove is located on the right side of the bottom end of the current transformer shell 1, and installation and later maintenance are convenient to conduct.

The utility model discloses a theory of operation is: the standard fixed resistor 6 is utilized to short circuit the mutual inductor S1 terminal 3 and the mutual inductor S2 terminal 4, the fact that high voltage occurs due to open circuit in the running process of the mutual inductor is guaranteed, electric shock caused by the high voltage is avoided, then the voltage at the two ends of the standard fixed resistor 6 is measured by utilizing the voltage to convert a current value, according to the fact that I is U/R, the voltage value U can be measured, the resistance R of the standard fixed resistor 6 is a known quantity, the current value I can be directly calculated, and the current mutual inductor is used for enabling a primary side to be connected with the current value I according to the electromagnetic induction principleThe instrument for measuring secondary side small current by converting large current into secondary side small current is characterized by that the current transformer is formed from closed iron core and winding, its primary side winding has small number of turns, and is series-connected in the circuit of current to be measured, so that it always has all the current of circuit flowing through, and its secondary side winding has more turns, and is series-connected in the measuring instrument and protection circuit, and when the current transformer is worked, its secondary side circuit is always closed, so that the impedance of series-connected coil of measuring instrument and protection circuit is very small, and the working state of current transformer is close to short circuit, and the current transformer can be used for converting primary side large current into secondary side small current to measure, and its secondary side can not be opened, and once it is opened, the primary side current I1 can be completely changed into magnetizing current, so as to cause that it can be opened

And E2 surge, cause the iron core to saturate and magnetize excessively, generate heat seriously and even burn out the coil; meanwhile, after the magnetic circuit is excessively saturated and magnetized, the error is increased, when the current transformer works normally, the secondary side is connected with current coils such as a measuring instrument and a relay in series for use, the impedance of the current coils such as the measuring instrument and the relay is very small, the secondary side is similar to short circuit, the magnitude of CT secondary current is determined by primary current, the magnetic potential generated by the secondary current is the magnetic potential of balanced primary current, if the current transformer is suddenly opened, the excitation electromotive force is suddenly changed from a very small value to a very large value, and the magnetic flux in the iron core presents a severely saturated flat-top wave, so that a secondary side winding can induce a very high sharp-top wave at the zero-crossing of the magnetic flux, the value can reach thousands or even tens of thousands of volts, and the safety of workers and the insulation performance of the instrument are threatened.

The above, only be the concrete implementation of the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art is in the technical scope of the present invention, according to the technical solution of the present invention and the utility model, the concept of which is equivalent to replace or change, should be covered within the protection scope of the present invention.

Claims

1. Voltage type current transformer, including current transformer shell (1), its characterized in that: the utility model discloses a current transformer, including current transformer shell (1), front movable connection have mutual-inductor S1 terminal (3), the front movable connection of current transformer shell (1) has mutual-inductor S2 terminal (4), the bottom fixed mounting of current transformer shell (1) has supporting baseplate (5), the front fixed mounting of current transformer shell (1) has standard fixed value resistor (6), joint groove (7) have been seted up on the front top of supporting baseplate (5).

2. The voltage type current transformer of claim 1, wherein: the size and the shape of the transformer S1 terminal (3) and the transformer S2 terminal (4) are the same, and the transformer S1 terminal (3) is positioned right to the left of the transformer S2 terminal (4).

3. The voltage type current transformer of claim 1, wherein: the left side of the standard fixed value resistor (6) is fixedly installed with the outer wall of the terminal (4) of the transformer S2, and the right side of the standard fixed value resistor (6) is fixedly installed with the outer wall of the terminal (3) of the transformer S1.

4. The voltage type current transformer of claim 1, wherein: the number of the clamping grooves (7) is two and the clamping grooves are respectively called as a left clamping groove and a right clamping groove, the left clamping groove is located on the left side of the bottom end of the current transformer shell (1), and the right clamping groove is located on the right side of the bottom end of the current transformer shell (1).

5. The voltage type current transformer of claim 1, wherein: the inner wall fixed mounting of mutual-inductor S1 terminal (3) has the wire, wire and voltmeter fixed connection, the inner wall fixed mounting of mutual-inductor S2 terminal (4) has the earth connection.

6. The voltage type current transformer of claim 1, wherein: the front side of the protective shell (2) is provided with a filling groove, and the back side of the protective shell (2) is fixedly connected with the front side of the current transformer shell (1).