CN211045251U - Current transformer with open circuit and short circuit detection - Google Patents

Abstract

The utility model relates to a mutual-inductor technical field, concretely relates to area short circuit detection's current transformer opens a way, including casing and apron, three cavity is separated into with the casing to the inside insulated column that is provided with of casing, has put the magnetic core in every cavity, twines secondary coil on every magnetic core, the outside one side of casing is provided with the tip of elementary lead wire, elementary lead wire penetrates three secondary coil's center to the inside opposite side of casing and winds back to the casing outside from the secondary coil outside from the casing outside, the apron is connected with the casing cooperation, the inboard of apron is provided with six and draws the needle draw-in grooves, draw and all set up secondary in the needle draw-in groove, two tip of every secondary coil are connected with two corresponding secondary draw needles respectively, the inside insulating material epoxy that fills of casing. The utility model discloses it is small, and can judge operating condition, in time handle the trouble or avoid the people to steal the electricity.

Description

Current transformer with open circuit and short circuit detection

Technical Field

The utility model relates to a mutual-inductor technical field, concretely relates to area short circuit detection's of opening a way current transformer.

Background

The current transformer belongs to a key component in the electric meter and is mainly used for measuring the flowing actual current and completing the collection and calculation of electric energy together with a voltage collection device in the electric meter. In recent years, with the increase of electrical equipment, accidents caused by current transformers are increased continuously, and the malfunction or the failure of the current transformers cause the misoperation or the rejection of protection, so that it is very important to detect working state signals, correctly judge the malfunction of the current transformers and timely process the malfunction. However, the conventional current transformer is basically a primary multi-turn current transformer due to the requirement of signal detection strength, and is relatively complex to manufacture, large in size and low in production efficiency.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the not enough of above-mentioned technique and providing a current transformer that short circuit detected opens a way in area, it is small, and can judge operating condition, in time handle the trouble or avoid the people for stealing the electricity.

In order to achieve the above object, the current transformer with open circuit and short circuit detection comprises a housing and a cover plate, wherein the housing is internally provided with an isolation column to separate the housing into three chambers, each chamber is internally provided with a magnetic core, a first magnetic core, a second magnetic core and a third magnetic core are sequentially arranged from one side to the other side, the magnetic cores are wound with a corresponding first secondary coil, a corresponding second secondary coil and a corresponding third secondary coil, one side of the outer part of the housing is provided with an end part of a primary lead, the primary lead penetrates through the centers of the three secondary coils from the outer part of the housing to the other side of the inner part of the housing and is wound back to the outer part of the housing from the outer part of the secondary coil, the cover plate is connected with the housing in a matching way, the inner side of the cover plate is provided with six lead pin clamping grooves, secondary lead pins are arranged in the lead pin clamping grooves, and two end, two ends of the second secondary coil are connected with two of the secondary pins, two ends of the third secondary coil are connected with two of the secondary pins, and the shell is filled with insulating material epoxy resin.

Among the above-mentioned technical scheme, the casing is inside to be provided with three magnetic core, and all around there being secondary, if the distance between the coil can not be guaranteed, arouses withstand voltage breakdown and signal interference's problem easily, so set up the insulated column on the casing of this product, fully guaranteed the distance between the coil, also can not influence production efficiency simultaneously. In addition, compared with the conventional current transformer, the primary turn number of the current transformer is small, only 1 turn is needed, the requirement on the detection strength of signals can be met, and the current transformer has the advantages of simplicity in manufacturing, small size, low cost and the like, and is suitable for mass production. Three magnetic cores in the casing, middle one is used for the measurement, and has anti 40A direct current function, and two magnetic cores of both sides are through injecting the signal of certain frequency range into one of them, and another is used for the detected signal, through the state of detected signal, are used for judging the different operating condition of short circuit, open circuit and normal use of table outer power current transformer, and the maintenance can in time be judged during the trouble, also can avoid the artificial electricity of stealing.

Preferably, the upper end and the lower end of the inner side of the cover plate are provided with buckles, and the shell is provided with a clamping groove matched with the buckles for use.

Preferably, the outer portion of each of the magnetic cores is covered with an insulating case, and the secondary coil is wound on the outer portion of the insulating case.

Preferably, the secondary needle is a square right-angle needle of 0.64mm x 0.64mm, six secondary needles are arranged in a row, and two ends of each secondary coil are respectively connected with two corresponding secondary needles. The square right-angled guide needle is not easy to rotate after being inserted into the cover plate, and the inserting side of the secondary guide needle is provided with a guide needle clamping groove for clamping and positioning. And two ends of the secondary coil are respectively connected with two corresponding secondary leading pins, so that wiring disorder can be avoided.

Preferably, the inner side of the cover plate is provided with a needle guide barrier strip, the needle guide barrier strip is connected with the cover plate in a clamping mode, a gap exists between the needle guide barrier strip and the inner surface of the cover plate, and the secondary needle guide is arranged between the needle guide barrier strip and the cover plate. The guide pin barrier is arranged to prevent the secondary guide pin from falling.

The utility model provides a current transformer that short circuit detected is opened a way in area, through reasonable structural design, simple manufacture, small can promote production efficiency effectively to through the state of detected signal, be used for judging current transformer's short circuit, open circuit and the different operating condition of normal use, accessible time judge during the trouble and repair, also can avoid the manual electricity of stealing.

The utility model has the advantages that:

1. the product meets the requirements of JB/T10665-2016 miniature current transformers;

2. the product is applied to 0.2S and 0.5S grade static active electric energy meters which accord with GB/T17215.322 standard;

3. the precision of the product can reach the requirement of 0.1 level, the linearity is better than 0.05 percent, and the product has the function of 40A direct current component;

4. filling materials (epoxy resin) are arranged among the three internal windings, the plastic box and the primary wire, so that the insulation withstand voltage can reach more than 4.5KV, the test lasts for 1 minute, and the leakage current is less than 0.5 mA;

5. insulation resistance

The insulation resistance between the primary winding and the secondary winding is more than 1G omega/500 Vdc.

Drawings

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

FIG. 2 is a schematic view of the inner structure of the cover plate omitted in the present invention;

FIG. 3 is a cross-sectional view taken along line K-K of FIG. 1;

FIG. 4 is a sectional view taken along line G-G of FIG. 1;

FIG. 5 is a sectional view taken along line H-H in FIG. 1;

FIG. 6 is a schematic diagram of the operation of the present invention;

in the figure: 1. a primary lead; 2. a housing; 3. a cover plate; 4. an epoxy resin; 5. a secondary coil number one; 6. a first magnetic core; 7. an isolation column; 8. a secondary coil number two; 9. a second magnetic core; 10. a secondary coil No. three; 11. a magnetic core No. three; 12. a needle guide clamping groove; 13 secondary guide pins; 14. a needle guiding barrier strip; 15. a card slot; 16. and (5) buckling.

Detailed Description

The invention is further described by the following embodiments in conjunction with the accompanying drawings.

Example 1:

as shown in fig. 1 to 5, the current transformer with open-circuit and short-circuit detection described in this embodiment includes a housing 2 and a cover plate 3, where an isolation pillar 7 is disposed inside the housing 2 to separate the housing 2 into three chambers, each chamber is provided with a magnetic core, a first magnetic core 6, a second magnetic core 9, and a third magnetic core 11 are sequentially disposed from one side to the other side, a first secondary coil 5, a second secondary coil 8, and a third secondary coil 10 are wound on the magnetic cores, an end of a primary lead 1 is disposed on one side outside the housing 2, the primary lead 1 penetrates through centers of the three secondary coils from the outside of the housing 2 to the other side inside the housing 2 and winds back to the outside of the housing 2 from the outside of the secondary coils, the cover plate 3 is connected to the housing 2 in a matching manner, six lead pin slots 12 are disposed on an inner side of the cover plate 3, and secondary lead pins 13 are disposed in the lead pin slots, two ends of the first secondary coil 5 are connected with two of the secondary pins 13, two ends of the second secondary coil 8 are connected with two of the secondary pins 13, two ends of the third secondary coil 10 are connected with two of the secondary pins 13, and the inside of the housing 2 is filled with the insulating material epoxy resin 4.

The upper end and the lower end of the inner side of the cover plate 3 are provided with buckles 16, and the shell 2 is provided with a clamping groove 15 matched with the buckles 16 for use.

And the outside of each magnetic core is covered with an insulating shell, and a secondary coil is wound outside the insulating shell.

The secondary needle 13 is a square right-angle needle with 0.64mm x 0.64mm, six secondary needles 13 are arranged in a row, and each secondary coil is respectively connected with two corresponding secondary needles 13.

The inboard of apron 3 is provided with needle guide blend stop 14, needle guide blend stop 14 and apron 3 joint, there is the clearance in needle guide blend stop 14 and the 3 internal surfaces of apron, secondary needle 13 sets up between needle guide blend stop 14 and apron 3.

The working principle is as follows: as shown in fig. 6, according to the principle of transformer impedance conversion, when the internal resistance of the primary side wire itself is ignored when viewed from the secondary side, the impedance of both ends N2 of the signal detection winding is set to

(1) When the primary is open, Z1 is infinite, the impedance Z of the signal detection winding is approximately equal to Z2, the "signal input winding" and the "signal detection winding" have no coupling relation, no matter what signal is injected into the "signal input winding", the "signal detection winding" cannot be detected, and then the "exterior CT open circuit" can be judged;

(2) when the primary is short-circuited, Z1 is approximately equal to 0, the impedance Z of the signal detection winding is very small and is parallel connection of the short-circuit impedance on the primary side and Z2;

(3) when the primary side is normally connected to the external CT, the impedance at both ends of the signal detection winding is

According to the coil impedance Z2 pi f L, resonance frequency

When the two conditions (2) and (3) exist, a range of frequency, such as 1K-20 KHz, is injected into the signal input winding, and then the detected resonant frequency point F is different due to different impedances, namely L, of the signal detection winding, and the detected resonant frequency point F is used for judging different working states of short circuit, open circuit and normal use of the power current transformer outside the meter according to the range of the resonant frequency, so that faults can be timely processed or manual electricity stealing can be avoided.

Claims (5)

1. The utility model provides a current transformer that short circuit that opens a way detects in area which characterized in that: the transformer comprises a shell (2) and a cover plate (3), wherein an isolation column (7) is arranged in the shell (2) to separate the shell (2) into three chambers, a magnetic core is arranged in each chamber, a first magnetic core (6), a second magnetic core (9) and a third magnetic core (11) are sequentially arranged from one side to the other side, a corresponding first secondary coil (5), a corresponding second secondary coil (8) and a corresponding third secondary coil (10) are wound on the magnetic cores, one side of the outer portion of the shell (2) is provided with an end portion of a primary lead (1), the primary lead (1) penetrates through the centers of the three secondary coils from the outer portion of the shell (2) to the other side of the inner portion of the shell (2) and is wound back to the outer portion of the shell (2) from the outer portion of the secondary coils, the cover plate (3) is connected with the shell (2) in a matched mode, six lead clamping grooves (12) are arranged on the inner side of the cover plate (3), and secondary, two ends of the first secondary coil (5) are connected with two secondary pins (13), two ends of the second secondary coil (8) are connected with two secondary pins (13), two ends of the third secondary coil (10) are connected with two secondary pins (13), and the shell (2) is filled with insulating substance epoxy resin (4).

2. The current transformer with open circuit and short circuit detection according to claim 1, characterized in that: the upper end and the lower end of the inner side of the cover plate (3) are provided with buckles (16), and the shell (2) is provided with a clamping groove (15) matched with the buckles (16) for use.

3. The current transformer with open circuit and short circuit detection according to claim 1, characterized in that: and the outside of each magnetic core is covered with an insulating shell, and a secondary coil is wound outside the insulating shell.

4. The current transformer with open circuit and short circuit detection according to claim 1, characterized in that: the secondary guide pins (13) are square right-angle guide pins of 0.64mm x 0.64mm, six secondary guide pins (13) are arranged in a row, and two ends of each secondary coil are respectively connected with the two corresponding secondary guide pins (13).

5. The current transformer with open circuit and short circuit detection according to claim 1, characterized in that: the inboard of apron (3) is provided with and draws needle blend stop (14), draw needle blend stop (14) and apron (3) joint, there is the clearance in drawing needle blend stop (14) and apron (3) internal surface, secondary draws needle (13) and sets up between drawing needle blend stop (14) and apron (3).

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