JP2005311064A - Isolation transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the cost-down, the miniaturization and the reduction of weight of an isolation transformer equipped with an inductance function which suppresses a lightning surge. <P>SOLUTION: A primary winding 21 wound around the outer periphery of a secondary winding unit 22 is divided into a pair of terminal windings 21a, 21b at both ends, and an intermediate winding 21c at a middle part between the windings 21a, 21b to connect both the ends of the intermediate winding 21c and the respective end windings 21a, 21b through respective intermediate taps 31, 32. Thus, an inductance and a noise filter are constituted for suppressing the lightning surge and the abnormal voltage of external noise by the respective end windings 21a, 21b. The respective windings 21a-21c are wound around to an iron core 40 by additive polarity to constitute the primary winding 21. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an insulation transformer used for a power supply system of various electrical facilities and electrical equipment.

  The lightning protection system of the power supply system using an insulation transformer includes a lightning protection system with a lightning protection transformer in front of the insulation transformer and an arrester system with an arrester between the ground and the primary side of the insulation transformer (for example, Patent Document 1). The former lightning-resistant transformer system is excellent in lightning-proof protection effect, but because it is necessary to install different types of transformers twice, the capital investment cost is high and a wide installation place is required, so the application is narrow. Limited. In the latter arrester method, several arresters are connected between the primary winding of the isolation transformer and the ground terminal. Since the arresters are inexpensive and small commercial products can be used, the power supply system can be configured economically and is narrow. It can be installed in a location and is highly practical.

  In the arrester type power supply system, if a large lightning surge flows through the arrester, the potential of the grounding part of the arrester rises to 20-30 kV, and the grounding of the arrester and the secondary load of the isolation transformer is completely connected Therefore, it is difficult to stably protect the load against a large lightning surge when it is difficult to perform separate grounding and it is difficult to connect a plurality of loads on the secondary side. Therefore, in order to provide a stable lightning protection function against large lightning surges, an inductance (such as a commercially available choke coil) that suppresses abnormal voltages such as lightning surges is inserted on the primary side of the isolation transformer. It has been broken. A circuit example of an arrester type power supply system using such an inductance will be described with reference to FIG.

  FIG. 7 shows a low-voltage lightning-proof insulation transformer 1. This insulation transformer 1 has a primary winding 11 connected to the power supply line 3 from the power receiving transformer 2 grounded in class B and a secondary winding 13 connected to a load 14. The secondary winding 13 is wound around the iron core 12, and the primary winding 11 is wound around the outer periphery of the secondary winding 13. The lightning protection in the insulation transformer 1 is performed by a lightning protection device 4 provided between both ends of the primary winding 11 and the ground, and an inductance 7 interposed between both ends of the primary winding 11 and the power line 3. The lightning protection device 4 shown in FIG. 7 includes the arrester 5 provided between each power line 3 and the ground terminal 6, but may be a method in which another lightning protection device such as a capacitor or a gap is added. In addition, the code | symbol 8 of FIG. 7 is a grounding resistance.

In the power supply system of FIG. 7, if a large lightning surge flows from the receiving transformer 2 side to the power supply line 3, the inductance 7 functions as follows with respect to the lightning surge. That is, since the lightning surge is a wave of a high frequency component of about 10 to 100 kHz that rises quickly, the inductance 7 acts as a high impedance. Therefore, the current due to this lightning surge is limited. On the other hand, the applied voltage is divided by the inductance 7, the lightning protection device 4 and the grounding resistance 8. However, when the lightning surge is applied, the lightning protection device is reduced in impedance, so the lightning surge voltage is shown in FIG. As in the equivalent circuit of FIG. 8, most of the voltage is shared by the inductance 7. This suppresses the potential increase on the insulating transformer 1 side and the ground side of the arrester 5, thereby facilitating protection of the load 14 from a large lightning surge and stable lightning protection. In addition, since the inductance 7 also has a noise filter function that suppresses abnormal voltage such as external noise entering the power supply line 3, when the load 14 is a low voltage device, malfunction due to noise of the load 14 is suppressed. .
JP-A-10-170599

  A low-voltage lightning-proof insulated transformer incorporating an arrester and an inductance as shown in FIG. 7 has an excellent function of protecting low-voltage equipment from lightning surges. However, in order to maintain a high lightning protection function, it is necessary to use a separate product for the inductance connected to at least two primary sides of the isolation transformer. The inductance used for the lightning protection is larger and more expensive than the arrester, and its weight is large. Therefore, the insulation transformer with an inductance function becomes expensive and increases in weight. Such an insulation transformer has a practical value as a multifunctional and high-quality transformer having both an arrester function and an inductance function, but on the other hand, it is desired to be inexpensive and small and light.

  In view of such circumstances, an object of the present invention is to provide an insulating transformer that is inexpensive and can be easily reduced in size and weight without degrading quality.

  The insulation transformer according to the present invention includes a primary winding partitioned into a pair of end windings on both ends and an intermediate winding between the end windings, both ends of the intermediate winding and each end winding. Are connected by intermediate taps, and each end winding constitutes an abnormal voltage suppressing inductor.

  Here, the pair of end windings of the primary winding are the winding start side winding and winding end side winding of the same number of turns from the winding start and winding end of the primary winding. An intermediate winding having a large number of main turns is arranged between the wires. The specific configuration of the insulation transformer is to wind a secondary winding (secondary winding, tertiary winding, etc.) around the iron core and place the primary winding on the outer periphery of this secondary winding. The primary winding is divided into three windings of a pair of end windings and one intermediate winding, and the three windings are connected in series via two intermediate taps. The number of turns of each end winding at both ends of the primary winding is set to a desired number of turns that functions as an inductor that suppresses abnormal voltage such as lightning surge and external noise. By doing so, each end winding of the primary winding of the insulation transformer exhibits the function of a normal winding along with the intermediate winding in normal times without lightning surge or external noise, and the secondary winding In the unlikely event of lightning surge or external noise, it functions as an inductance or noise filter that suppresses abnormal voltage in combination with an external lightning protection device. Therefore, the transformer of the present invention is an isolation transformer with an inductance function and a noise filter function in which inductance is integrated into the primary winding side, and a separate inductance is omitted from the conventional isolation transformer with a separate inductance. The insulation transformer with inductance function and noise filter function is made inexpensive and small and lightweight.

  In the present invention, in the primary winding, an electrostatic shield is provided between the pair of end windings and the other windings laminated to each end winding, and the electrostatic shield is grounded. And In this case, the end winding of the inductance can be shielded from the surge transition voltage by the stray capacitance formed between the end winding acting as the inductance and the other winding, and the inductance function and the noise filter function Performance improvement and stabilization can be achieved.

  In the present invention, a lightning protection element including an arrester can be provided between the intermediate tap and the ground terminal in the primary winding. Here, the lightning protection element is an arrester, a gap or a capacitor, and at least a plurality of arresters are grounded at a single point to a common earth terminal. By doing so, the potential increase on the ground side due to the lightning surge of the arrester is suppressed by the inductance action of the end winding of the primary winding, and the efficiency of the function as the inductance of the end winding can be improved. And lightning protection performance due to the synergistic effect of the arrester.

  In the present invention, the primary winding is wound around the outer periphery of the secondary winding portion wound around the iron core, and the lightning protection including the arrester is provided between the secondary winding portion and the primary ground terminal. An element can be provided. By doing in this way, the grounding point of the arrester on the primary winding side and the grounding point of the arrester on the secondary winding part are consolidated into one point, and the intermediate winding and secondary winding on the primary side of the isolation transformer Can be made the same potential, and the lightning protection effect is more stable.

  In the present invention, the pair of end windings in the primary winding can be a high voltage insulation strength winding higher than the insulation strength of the intermediate winding. The end winding having high voltage insulation strength can be composed of an insulated wire or a resin molded wire. When lightning surge voltage is applied to the primary winding, most of the surge voltage is applied to the end winding at the beginning and end of winding, which acts as an inductance. By doing so, the insulation is stabilized even against a large lightning surge, and the inductance action of the end winding is stabilized.

  In the present invention, the primary winding is wound around the outer periphery of the secondary winding portion wound around the iron core, the end winding is the outermost periphery of the primary winding, and the end winding The lead terminal side at the beginning and end of winding of the wire can be adjacent at the outermost central portion, and the other intermediate winding side can be provided at both ends of the outermost periphery. In this way, the high potential application part on the lead terminal side at the beginning and end of winding and the low potential part on the iron core and intermediate winding side can be gathered for the lightning surge, and the overall insulation design is easy. This has the effect of enabling downsizing.

Further, in the present invention, one end winding can be arranged on the inner peripheral side of the intermediate winding in the primary winding, and the other end winding can be arranged on the outer peripheral side of the intermediate winding. By arranging a pair of end windings on the inner and outer peripheral sides of the intermediate winding in this way, a pair of end windings that require high-voltage insulation strength are added to the middle because lightning surge is concentrated and applied. Since the windings are separated, the insulation design of the pair of end windings is facilitated, and the inductance function of the end windings is stabilized.

  In the present invention, it is desirable to wind both the pair of end windings and the intermediate winding in the primary winding in the direction of the additional polarity with respect to the iron core. That is, the number of turns that each pair of end windings and intermediate windings are wound around the iron core with the same polarity to induce voltage in the iron core to function as a transformer for the primary winding. By making the total number of end windings and intermediate windings, the winding design of the transformer is facilitated.

  According to the present invention, each end winding of the primary winding in the insulation transformer can be functioned as an inductance and noise filter for suppressing abnormal voltage of lightning surge and external noise. An insulation transformer with an inductance function or a noise filter function can have a structure in which an inductance and a noise filter are integrated, and the insulation transformer with an inductance function and a noise filter function can be reduced in size and weight. It is possible to reduce the cost, and to provide an insulation transformer with excellent practical value that can be applied to a narrow space.

  Hereinafter, various embodiments of the present invention will be described with reference to FIGS.

  FIG. 1A is an outline of the insulation transformer 20, and FIG. 1B is an equivalent circuit of the insulation transformer 20. The insulation transformer 20 is formed by winding a primary winding 21 and a secondary winding 22 around an EI type iron core 40. The primary winding 21 is wound on an end winding 21a and a winding end side end. The winding 21b is divided into an intermediate winding 22c between the end windings 21a and 21b, one end winding 21a and the intermediate winding 21c are connected by an intermediate tap 31, and the other end winding. 21b and the intermediate winding 21c are connected by an intermediate tap 32. The primary winding 21 is wound around the outer circumference of the secondary winding portion 22 wound around the iron core 40. The primary winding 21 has lead terminals 33 and 34 at both ends of the winding, and the secondary winding 22 has lead terminals 35 and 36 at both ends of the winding. Although the secondary side winding portion 22 shown in FIG. 1 is only the secondary winding, a structure having a tertiary or higher winding is also possible, so the secondary side winding is connected to the winding portion 22. Called.

  FIG. 2 shows a circuit example in which the insulation transformer 20 of FIG. 1 is used as a low-voltage lightning-proof insulation transformer, and a pair of intermediate taps 31 and 32 drawn from the primary winding 21 of the insulation transformer 20 and a single ground terminal Arrester 51 is provided between 53 and constitutes lightning protection device 50. Reference numeral 14 in FIG. 2 is a load similar to that in FIG. 7, and 54 is a grounding resistance. The power receiving transformer 2 in FIG. 2 is the same as that in FIG. 7, and the power line 3 is connected to the terminal 33 on the winding start side and the terminal 34 on the winding end side of the primary winding 21 of the insulation transformer 20. . Here, the terms “start of winding” and “end of winding” are used to classify the windings wound around the iron core, and do not mean the start and end of the work of winding an electric wire around the iron core. The secondary winding 22 has lead terminals 35 and 36 at both ends.

  The insulation transformer 20 sets the number of turns of the pair of end windings 21a and 21b on both ends of the primary winding 21 to about the number of turns (5 to 10 turns) having an inductance action for suppressing abnormal voltage of lightning surge. Thus, each end winding 21a, 21b can be used as an inductor and an inductance L. The end windings 21a and 21b having the number of turns having the inductance function also have a function of a noise filter for suppressing an abnormal voltage of external noise. Each end winding 21a, 21b in the normal state without lightning surge functions as a primary winding in the transformer, and an inductance or a noise filter that suppresses abnormal voltage only when there is a lightning surge or external noise in the power line 3 Function as. Accordingly, the insulation transformer 20 has a structure in which the primary winding 21 is integrally provided with an inductance and a noise filter as a lightning protection element, and has a structure in which the conventional separate inductance and noise filter coil parts are omitted. Corresponding to the omission of the coil parts, the size and weight are reduced, and the manufacturing cost is reduced.

  Further, in the insulation transformer 20 shown in FIG. 1A, the intermediate winding 21c of the primary winding 21 is wound around the outer periphery of the secondary side winding portion 22 wound around the iron core 40, and this intermediate winding 21c. A pair of end windings 21a and 21b are wound adjacently to both ends of the outer periphery of each of the outer peripheral taps, and the intermediate taps 31 and 32 are taken out from both ends of the intermediate winding 21c. In this case, the intermediate winding 21c of the secondary winding 22 and the primary winding 21 is interposed between the iron core 40 and the end windings 21a and 21b, so that the intermediate between the both ends of the iron core 40 and the intermediate winding 21c. A large separation distance between the taps 31 and 32 and the end windings 21a and 21b can be secured, and a stable insulation design on the primary winding 21 side against a large lightning surge is facilitated, and lightning of the end windings 21a and 21b is facilitated. The inductance function against surge is stabilized.

  3A and 3B are conceptual diagrams showing an embodiment in which the pair of end windings 21a and 21b of the primary winding 21 have a high voltage insulation strength winding structure higher than the insulation strength of the intermediate winding 21c. is there. FIG. 3A shows a configuration in which the end windings 21 a and 21 b are constituted by insulated wires 24. The insulated wire 24 is obtained by coating the wire with an insulating film, and makes the entire end windings 21a and 21b have a stable high-voltage insulation strength. FIG. 3B shows a configuration in which the end windings 21 a and 21 b of the electric wire are covered with a resin mold 25. In the case of FIG. 3B, the same wire as the intermediate winding 21c can be applied to the end windings 21a and 21b. In either case of FIGS. 3A and 3B, lightning protection measures can be effectively performed. That is, when the lightning surge voltage is applied to the primary winding 21, most of the surge voltage is applied to the winding end windings 21a and 21b that act as inductances. By using a high-voltage insulation strength winding, the insulation is stable against a large lightning surge. Therefore, the end windings 21a and 21b always exhibit a stable inductance function even with a large lightning surge, and the lightning protection measures are stably executed.

  The insulation transformer 20 shown in the embodiment of FIG. 4 is obtained by changing the winding form of the primary winding 21. The primary winding 21 is disposed on the outer periphery of the secondary winding portion 22 wound around the iron core 40, and one end winding 21a is disposed on the inner periphery side of the intermediate winding 21c. The other end winding 21b is wound on the side. Such winding may be performed in the order of the end winding 21a → the intermediate winding 21c → the end winding 21b around the outer periphery of the secondary winding portion 22 in the winding direction of FIG.

  In the insulation transformer 20 according to the embodiment shown in FIG. 5, an electrostatic shield 26 provided between the pair of end windings 21 a and 21 b and the secondary winding portion 22 of the primary winding 21 is connected to the ground terminal 53. Is grounded. The electrostatic shield 26 is a copper plate or the like used between the windings of a normal transformer, and is grounded at one point to the same ground terminal 53 as the arrester 51 so as to act as an inductance against a lightning surge. The inductance L is shielded from the surge transition voltage by the stray capacitance formed between the windings 21a and 21b and the other windings, and the performance of the inductance function and noise filter function of the end windings 21a and 21b is improved. , Become stable.

  In the insulation transformer 20 of the embodiment shown in FIG. 6, an arrester 51 ′, which is a lightning protection element, is provided between the secondary winding portion 22 and the ground terminal 53 of the primary lightning protection circuit 50. 6 is a secondary winding and a tertiary winding, and an arrester may be provided between both ends of the secondary winding and between both ends of the tertiary winding. . Thus, in the insulation transformer 20, the primary side and the secondary side can be made the same potential by grounding the primary side and the secondary side through the arrester, so that the primary winding 21 can have the same potential. The inductance function of the end windings 21a and 21b and the lightning protection effect by the arrester are more stable.

  In addition, this invention is applicable not only to a low voltage | pressure lightning-proof insulation transformer but other insulation transformers including a high voltage | pressure lightning-proof insulation transformer.

(A) is a front view of an insulation transformer showing an embodiment of the invention, and (B) is an equivalent circuit diagram of the insulation transformer. FIG. 2 is an equivalent circuit diagram of a power supply system using the insulation transformer of FIG. 1. (A) And (B) is a partial expanded sectional view which shows the form from which the primary winding in the insulation transformer of FIG. 1 differs. It is a front view of the insulation transformer which shows other embodiment of this invention. FIG. 6 is a configuration circuit diagram showing still another embodiment of the present invention. FIG. 6 is a configuration circuit diagram showing still another embodiment of the present invention. It is a structure circuit diagram of the power supply system which uses the conventional insulation transformer. It is explanatory drawing to which the lightning surge was applied in the equivalent circuit of FIG.

Explanation of symbols

20 Insulation transformer 21 Primary winding 21a, 21b End winding, Inductor L Inductance 21c Intermediate winding 22 Secondary winding 24 Insulated wire 25 Resin mold 26 Electrostatic shield 31, 32 Intermediate tap 33, 34 Drawer terminal 35 Earth terminal 40 Iron core 50 Lightning protection circuit 51, 51 'Arrester

Claims (9)

  Connect both ends of the intermediate winding and each end winding of the primary winding divided into a pair of end windings on both ends and an intermediate winding between the end windings with an intermediate tap. In addition, an insulation transformer characterized in that each end winding is an inductor for suppressing abnormal voltage.   The electrostatic shield is disposed between the pair of end windings and the other windings laminated with the end windings, and the electrostatic shield is grounded. Insulation transformer as described.   The insulation transformer according to claim 1, wherein a lightning protection element including an arrester is provided between the intermediate tap and the ground terminal.   The primary winding is wound around an outer periphery of a secondary winding portion wound around an iron core, and a lightning protection element including an arrester between the secondary winding portion and the primary ground terminal is provided. The insulation transformer according to claim 3, wherein the insulation transformer is provided.   The insulation transformer according to claim 3, wherein the pair of end windings are high-voltage insulation strength windings higher than the insulation strength of the intermediate winding.   6. The insulation transformer according to claim 5, wherein the end winding is an insulated wire.   The primary winding is wound around the outer periphery of the secondary winding portion wound around the iron core, the end winding is the outermost periphery of the primary winding, and the winding of the end winding is started. 2. The insulation transformer according to claim 1, wherein the lead terminal side at the end of winding is adjacent to the outermost central portion, and the other intermediate winding side is provided at both ends of the outermost periphery.   7. One of the end windings is arranged on the inner peripheral side of the intermediate winding in the primary winding, and the other end winding is arranged on the outer peripheral side of the intermediate winding. Isolation transformer according to crab.   The insulation transformer according to any one of claims 1 to 8, wherein the pair of end windings and the intermediate winding in the primary winding are both wound in a direction of polarity with respect to the iron core.

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