KR100832876B1 - Ct winding method of mof - Google Patents

Abstract

A CT(Current Transformer) and a method for winding the same are provided to entirely reduce a size by reducing a size of a core by including a primary winding having a small winding number and a secondary winding having two kinds of copper wires with different current densities. A CT includes a primary winding, a secondary winding(52), and a core. The primary winding is constructed by winding single copper wires on a frame at a predetermined number of times. The secondary winding is constructed by winding copper wires having relatively small current density among a plurality of copper wires with different current densities from each other on the frame less than the predetermined number of times by one to three times and winding copper wires having large relatively current density on the frame wound by the single copper wires at the predetermined number. The core is made of a silicon steel lamination.

Description

Current transformer for instrument and its winding method {CＴ winding method of MＯＦ}

1 is a front view showing a conventional transformer for power supply (MOW),

Figure 2 is a view showing the internal structure of the instrument transformer MOP of Figure 1,

3 and 4 is a view showing the current transformer CT of the instrument 2 and its secondary winding,

5 and 6 show a current transformer for the instrument (CT) and a secondary winding thereof according to the present invention.

<Description of the symbols for the main parts of the drawings>

50: current transformer (CT) 51: primary winding

52: secondary winding 53: core

Ｋ, ｋ, ｋ ₁ , ｋ ₂ : Start line Ｌ, ｌ, ｌ ₁ , ｌ ₂ : End line

The present invention relates to a winding method of an instrument current transformer (CT) built in an electric power supply transformer (MOF). More specifically, the secondary windings of the instrument current transformer (CT) have different current densities. The present invention relates to an instrument current transformer (CT) and a winding method thereof, in which two types of copper wire are wound twice to reduce the size compared to the conventional winding of a single copper wire.

Typically, metering out transformers (MOFs) are used to reduce the high voltages and currents of transmission and distribution lines for use in combination with power supply meters, reactive voltage meters (VARHM), or maximum demand meters (DM). It is an electric device that denatures precisely (within 5% of error) by voltage and current. This is a necessary equipment for the accurate calculation and collection of electricity bills based on the measurement of the amount of power used by industrial consumers, that is, relatively large consumers, such as factories and buildings.

On the other hand, the instrument transformer MOP is provided with a Potential Transformer (PT) for converting a high voltage into a low voltage and a Current Transformer (CT) for precisely transforming a high current into a low current. In particular, the three-phase four-wire MOP has three current transformers and three instrument transformers, and is mainly used as a transformer for measuring the amount of power used in combination with an integrated power meter.

In addition, the instrument transformer (PT) is usually used for the use of a transformer having a secondary side of 100V because it is dangerous to measure a high voltage directly by a voltmeter and is very uneconomical in view of the insulation of the voltmeter. The types of instrument transformers used in this way can be roughly classified into dry, inflow and gas.

In addition, the instrument current transformer CT refers to an instrument transformer for modifying a certain current value to a current value proportional thereto. In general, the rated input current of common instruments and protective relays is 5A, but the rated input current of digital relays, which have been developed and spread in recent years, is manufactured to be 1A. As it is not possible to measure directly, it is a transformer that can measure the instrument by lowering the current to a certain ratio.

An example of such a conventional instrument transformer MOP will be described with reference to FIGS. 1 and 2.

1 shows a front view of a conventional instrument transformer MOP, and FIG. 2 shows the internal structure of the instrument transformer MOP of FIG.

According to this, the upper part of the instrument transformer MOF consists of three tube-like porcelain bushings 1, 2, and 3, and one ground bushing 4. As shown in FIG. Each of the three bushings (1, 2, 3) is filled with an apex and an air in the inner diameter, whereby a primary side rod (6) and a primary side rod (6) into which a large current flows into the inside of the tube. The outflowing copper pipe 7 which flows in from and flows out through a meter current transformer 20 is provided. In particular, between the primary side rod (6) and the outflow copper pipe (7) is to maintain the insulation state by air insulation, and each of the upper bushings in the primary side rod (6) and outflow copper pipe (7) The input terminal 8 and the output terminal 9 made of the same material to be connected are formed.

In addition, only one PVC wire is grounded in the enclosure (5) for grounding in the grounding type bushing (4).

Subsequently, looking at the lower portion of the instrument transformer MOP, inside the enclosure 5 made of an iron tank, the number of windings of transformers 20 and transformers having the same number as the number of tube-type magnetic bushings formed on the upper portion of the instrument transformer. 10) A winding body is arranged. The instrument transformer (PT) winding 10 is provided with a primary winding 11 having four to eight layers and a secondary winding 12 therein, and a core 13 passing through the center thereof. . In particular, the current transformer (CT) 20 winding body is assembled as shown in FIGS. 3 and 4.

The current transformer (CT) 20 winding body has a primary winding 21 and a secondary winding 22 depending on the current flow ratio, and a core 23 made of silicon steel passes through the center thereof. do. For example, when the primary current is 10 A and the secondary current is 5 A, a copper wire having a predetermined current density is wound on each of the bobbins at a current ratio (winding ratio) of 2: 1. After the secondary frame is inserted therein, the core 23 is made of silicon steel sheets laminated into the secondary frame. Between the primary winding 21 and the secondary winding 22 is wound with insulation paper to be insulated. Here, when the secondary winding 22 is wound on the bobbin by the design of a single copper wire (one line) having a predetermined current density, a start line k and an end line l come out, which is a lead wire drawing body ( 30 is connected to the secondary terminal terminal 40.

2, the copper plate, the primary current transformers (CT) 20 and the primary leads 14 and 24 of the transformer (PT) 10 are connected to the bottom of the bushing, and the current transformer (CT) 20 for the instrument is connected to the bottom of the bushing. The secondary lead wires 15 and 25 of the transformer (PT) 10 are connected to the secondary terminal terminal 40 connected to the maximum demand power meter (not shown) through the drawing body 30.

The inside of the enclosure 5 is filled with an insulation oil (OT) to insulate the conductive parts between phases.

Instrument transformer MOP having such a structure has a large occupied area because 2-3 transformer (PT) windings and current transformer (CT) windings are installed at a distance from each other in the enclosure (5). There was a problem that the size of the.

Accordingly, an object of the present invention was devised in view of the above-mentioned point, and by winding two types of copper wires having different current densities, respectively, the secondary windings of the current transformer CT are wound by a single copper wire. Compared to the present invention, the present invention provides a current transformer (CT) and a winding method thereof for reducing the size of the winding to save materials and costs.

Instrument current transformer of the present invention for achieving the above object, a transformer for power supply instrument (MW) composed of a plurality of bushings, a plurality of instrument current transformers and transformers, the inner space is filled with insulating oil An instrument current transformer (CT) is configured and assembled by an error compensation method, and the instrument current transformer (CT) is configured by winding a single copper wire having a predetermined current density on a frame (bobbing) at design times. The windings and the copper wires with the relatively small current density among the plurality of copper wires having different current densities are wound a predetermined number of times less than the design number on the frame, and the copper wires having the relatively high current density are wound again on the design frequency. And a core composed of a laminated secondary steel sheet and a laminated silicon steel sheet.

Instrument current transformer winding method for achieving the object of the present invention, in the current transformer (CT) winding method of the instrument transformer (MOF) for power supply, (1) to determine the ampere (AT), the specified ampere Determining the primary and secondary turn ratios according to turns, (2) forming a primary winding by winding a single copper wire having a predetermined current density on a frame (bobbing) according to the determined primary turns ratio, (3) In order to reduce the influence on the error characteristics, the current compensation method has a different current density due to an error compensation method in which the primary and secondary current ratios are close to the nominal current ratios by performing a back turn to subtract the excitation current distribution turn ratio. Winding a plurality of copper wires on a frame (bobbing) in duplicate to form a secondary winding, and (4) inserting a secondary winding into the primary winding frame, and assembling a core around the core.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5 shows a current transformer CT winding body according to the present invention, and FIG. 6 is a view showing a secondary winding structure of the current transformer CT.

Referring to Fig. 5, the current transformer (CT) 50 winding body of the present invention winds a single copper wire having a predetermined current density on a primary frame (bobbing) to form a primary winding 51. The starting line K and the ending line L of the primary winding 51, that is, the primary side lead wire, include the primary side rod (6 in FIG. 2) and the outflow copper pipe into which the large current flows into the instrument current transformer MOP. It is connected to the input and output terminals (8, 9 of FIG. 2) through 7) of FIG. The secondary winding 52 of the instrument current transformer (CT) 50 winds the copper wire having the small current density less than a predetermined number of times, among the two types of copper wires having different current densities on the secondary frame (bobbing), On top of that, a copper wire with a relatively large current density is wound around the design frequency. In this embodiment, the copper wire having a relatively small current density is wound one to three times in the secondary winding. The secondary winding 52 is inserted into the frame of the primary winding 51, through which a core 23 made of silicon steel passes. In the case of the secondary winding 52, two start lines and two end lines are drawn out as shown in FIG. Connect the two wires (k ₁ , k ₂ ) where the secondary windings 52 are started (k) and the two wires (l ₁ , l ₂ ) which end are connected to each other (l) to form a secondary lead wire. The secondary lead wire is connected to the secondary terminal terminal 40 through the drawing body (30 in FIG. 2).

That is, the secondary winding 52 of the instrument current transformer (CT) 50 is changed into a structure in which two types of copper wires having different current densities are wound in duplicate instead of winding a single copper wire having a predetermined current density. This method is based on the error compensation method, and in order to reduce the influence of the error characteristic, a back turn is performed to reduce the excitation current only winding ratio, and thus the primary and secondary current ratios are close to the nominal current ratios. For example, in the conventional case, when the number of secondary windings is 170 times of 2.2 mm copper wires, when applying the present invention based on the error compensation method, two types of copper wires having a current density smaller than 2.2 mm are wound twice and wound more than 170 times. By constructing a secondary winding with reduced frequency, the material can be saved by reducing its size while keeping its characteristics equal or more.

That is, when designing a current transformer (CT) 50 for the instrument, the ampere turn (AT) is first determined. Amperton (AT) is the unit of magnetic force or masturbation in the MKS system, multiplied by the number of turns of the coil and the number of amperes of current flowing. In the embodiment of the present invention, the ampereton (AT) is set to 600 and the current ratio is 10A: 5A. Accordingly, the number of turns of the primary winding 51 is 60 (= 600/10) times, and the number of turns of the secondary windings 52 is designed to be 120 (= 600/5) circuits. At this time, in order to compensate for the error within ± 0.5 in the case of the secondary winding 52, one of the two types of copper wires having different current densities is wound 119 times, which is one less than the design number 120, and the current is relatively reduced. The dense copper wire is wound 120 times as many times as designed. In this case, the weight of the current transformer (CT) winding of the instrument is reduced.

Instrument current transformer of the present invention, the primary winding has the same current density as the primary winding of the conventional instrument current transformer, but the number of turns is reduced from 85 times to 60 times the weight is reduced, the secondary winding is the secondary winding of the conventional instrument current transformer Two types of copper wires with smaller different current densities are wound to reduce the weight from 0.92 kg to 0.64 kg. Accordingly, the size of the core 53 is also reduced to reduce the weight. Therefore, the size is reduced overall.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below but also by the equivalents of the claims.

As described above, the instrument current transformer of the present invention and the winding method thereof are configured by winding two types of copper wires having different current densities by double winding the current transformer secondary winding of the instrument by an error compensation method, thereby reducing the size. As a result, the material and the cost can be saved.

Claims (5)

In the electric power supply instrument transformer (MOF) composed of a plurality of bushings, a plurality of instrument current transformers and transformers, the inner space is filled with insulating oil, Instrument current transformer (CT) configured and assembled by the error compensation method, The instrument current transformer (CT) is A primary winding formed by winding a single copper wire on a frame (bobbing) as many times as designed; Among copper wires having different current densities, copper wires of relatively small current density are wound one to three times less than the number of design times on a frame (bobbing), and copper wires of relatively high current density are wound around the design number of times. Secondary winding; And Current transformer for instrument characterized in that it comprises a core consisting of a laminated silicon steel sheet. delete The instrument current transformer of claim 1, wherein the secondary windings of the instrument current transformer (CT) form a secondary lead wire by connecting a plurality of start lines to each other and connecting a plurality of end lines to each other. In the current transformer (CT) winding method of the electric power supply transformer (MOF), (1) determining an ampere turnover (AT) and determining primary and secondary turn ratios according to the determined amperage; (2) forming a primary winding by winding a single copper wire on a frame (bobbing) according to the determined primary turn ratio; (3) In order to reduce the influence on the error characteristics, the current is different due to the error compensation method in which the primary and secondary current ratios are close to the nominal current ratios by performing the back turn to add or subtract the excitation winding number ratio. Forming a secondary winding by winding a plurality of copper wires having a density on a frame (bobbing) in a double; And (4) A method of winding a current transformer for an instrument comprising inserting a secondary winding into a primary winding frame and assembling a core around the primary winding. The method of claim 4, wherein step (3) (3a) winding one or three times less copper wires having a smaller current density among two types of copper wires having different current densities; (3b) winding a copper wire having a relatively high current density thereon at a predetermined number of turns; And (3c) the method of winding the current transformer for the instrument, characterized in that it comprises the step of connecting the two wires started, and the two end wires connected to each other and connected to the secondary terminal terminal.

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