JPH0854434A - Method and device for detecting interlayer short-circuiting of superconductive coil - Google Patents

Abstract

PURPOSE:To surely and easily detect the interlayer short-circuiting of a superconductive coil by judging that the interlayer short-circuiting of a coil has occurred when the value of inductance of a superconductor wound around the superconductive coil at normal temperature changes exceeding a certain value within a preset reference time. CONSTITUTION:A superconductive coil 1 is manufactured by withdrawing a superconductor 3 from a drum 2 for winding halfway during winding operation. A lead wire 4 for measurement is connected to both terminals of the conductor 3 and an inductance measuring instrument 5 and a sequential comparator 6 are connected. The measuring instrument 5 measures the inductance of the conductor 3 wound around the coil 1 at normal temperature. The comparator 6 obtains the change rate with time of the inductance measured by the measuring instrument 5, compares the rate with a preset change rate, and then judges whether the interlayer short-circuiting of the coil 1 occurs or not, thus positively detecting the interlayer short-circuiting of the coil 1 in real time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for detecting an inter-layer short circuit of a superconducting coil such as a superconducting generator, especially in the course of manufacturing a superconducting coil whose inductance varies (during winding work). The present invention also relates to a method and a device for detecting an interlayer short circuit of a superconducting coil, which can detect the occurrence of an interlayer short circuit of the superconducting coil with a reliable and simple structure and at low cost.

[0002]

2. Description of the Related Art Generally, in a superconducting coil such as a superconducting generator, a superconducting conductor is wound many times to form a superconducting coil. The superconducting conductor is conductor-insulated to prevent the superconducting conductor wound a large number of times from being short-circuited between layers.

However, in the superconducting coil,
In order to maintain the superconducting state, there are many cases where a fine flow path for a coolant such as liquid helium is provided between the layers of the superconducting conductor, and if minute metal chips are mixed in this flow path, an interlayer short circuit will occur. There are cases. When an inter-layer short circuit occurs in the superconducting coil, a loop with very low electrical resistance is created, and when trying to change the coil current by changing the coil current, the loop that tries to prevent this An electric current is generated and the original performance of the superconducting coil cannot be realized. Therefore, when an inter-layer short circuit occurs in the superconducting coil, it is necessary to promptly improve the inter-layer short circuit portion, and it is important to detect the occurrence of the inter-layer short circuit.

By the way, in order to detect the occurrence of such an inter-layer short circuit of the superconducting coil, it is extremely effective to measure the inductance, and most of the inter-layer short circuits can be detected by such measurement. That is, this utilizes the fact that the inductance changes greatly due to the short circuit loop.

However, during the manufacture of the superconducting coil,
That is, during winding work, the long superconducting conductor wound in a drum shape is wound around the superconducting coil while being pulled out from the drum, so the inductance changes during winding work, causing an interlayer short circuit. Difficult to detect.

In addition, when the superconducting conductor is conductor-insulated, a lead wire for measurement may not be attached in the middle of the superconducting conductor. Therefore, in this case, when the superconducting coil is completed, the occurrence of the interlayer short circuit is detected by measuring the inductance.

However, at the time when the winding of the superconducting coil is completed, if it is detected that an interlayer short circuit occurs due to the inductance measurement, there is a case that a considerable work of returning is required to improve the interlayer short circuit portion. There is a problem that it becomes a factor that delays the manufacturing process.

[0008]

As described above, in the conventional method for detecting the occurrence of the interlayer short circuit of the superconducting coil, the inductance of the superconducting coil is changed during the manufacturing process (at the time of winding work). Since the inductance changes, it is difficult to detect the occurrence of the interlayer short circuit.

An object of the present invention is to reliably and easily generate an interlayer short circuit of a superconducting coil even at a stage such as during manufacturing of a superconducting coil (during winding work) where the inductance changes, and at a low cost. It is an object of the present invention to provide a method and a device for detecting an inter-layer short circuit of a superconducting coil which can be detected.

[0010]

In order to achieve the above object, first, in the invention according to claim 1, at the time of winding work for forming a superconducting coil by winding a plurality of superconducting conductors, an interlayer of the superconducting coil is formed. In the method of detecting a short circuit, an interlayer short circuit of the superconducting coil occurs when the value of the inductance of the superconducting conductor material wound around the superconducting coil at room temperature changes by a certain value or more within a preset reference time. I have decided to do.

Further, in the invention according to claim 2, in a device for detecting an interlayer short circuit of a superconducting coil during a winding work for forming a superconducting coil by winding a plurality of superconducting conductors,
Inductance measuring means for measuring the inductance of the superconducting conductor material wound around the superconducting coil at room temperature, and calculating the time change rate of the inductance measured by the inductance measuring means, and the time change rate of the inductance can be arbitrarily set in advance. An inter-layer short-circuit determination means for comparing the set reference time change rate and determining the occurrence of the inter-layer short circuit of the superconducting coil based on the comparison result.

[0012]

Therefore, in the method and apparatus for detecting the interlayer short circuit of the superconducting coil of the present invention, the inductance measuring means for measuring the inductance of the superconducting conductor material wound around the superconducting coil at room temperature and the inductance measuring means are used. Inter-layer short-circuit judgment that calculates the time-varying rate of inductance and compares the time-varying rate of the inductance with a previously set reference time-varying rate and determines the occurrence of an inter-layer short circuit of the superconducting coil based on the comparison result. When the inter-layer short circuit of the superconducting coil is detected, the value of the inductance of the superconducting conductor material wound around the superconducting coil at room temperature changes by a certain value or more within a preset reference time. In addition, the inductance changes when it is determined that an inter-layer short circuit has occurred in the superconducting coil. Also in step like way fabrication of superconducting coils (when winding operation), it is possible to reliably detect the occurrence of interlayer short of the superconducting coil.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration example of an inter-layer short-circuit detecting device for a superconducting coil according to the present invention.

In FIG. 1, the superconducting coil 1 is in the process of winding, and the superconducting conductor 3 drawn from the drum 2 is wound to manufacture the superconducting coil 1. Also,
A measuring lead wire 4 is connected to both ends of the superconducting conductor 3, and an inductance measuring instrument 5 and a successive comparator 6 which is an interlayer short-circuit judging means are connected to the measuring lead wire 4.

The inductance measuring device 5 is composed of a measuring device such as an LCR meter, and measures the inductance of the material of the superconducting conductor 3 wound around the superconducting coil 1 at room temperature.

On the other hand, the successive approximation comparator 6 is composed of, for example, an operational comparator, calculates the time variation rate of the inductance measured by the inductance measuring instrument 5, and determines the time variation rate of this inductance and a reference time preset arbitrarily. The rate of change is compared, and the occurrence of an interlayer short circuit of the superconducting coil 1 is determined based on the comparison result.

Next, an inter-layer short-circuit detecting method in the super-conducting coil inter-layer short-circuit detecting apparatus of the present embodiment having the above-mentioned structure will be described. In this embodiment, basically, the decrease in the inductance of the entire length of the material of the superconducting conductor 3 at room temperature is detected, and the occurrence of the interlayer short circuit of the superconducting coil 1 is detected.

That is, first, the inductance measuring device 5
Thus, the inductance of the entire length of the material of the superconducting conductor 3 wound around the superconducting coil 1 at room temperature is measured. The accuracy of the inductance measuring device 5 is 1 of the superconducting coil 1.
It is necessary to have an accuracy that can detect that the turn is short-circuited and the inductance is reduced.

The problem here is that the inductance of the superconducting conductor 3 during the winding operation changes depending on the winding condition of the superconducting coil 1. The amount of the superconducting conductor 3 wound on the drum 2 and the superconducting conductor 3 are different. Superconducting conductor 3 wound around coil 1
Therefore, the total inductance seen from both ends of the superconducting conductor 3 changes depending on the winding condition of the superconducting coil 1.

Therefore, in order to eliminate such a factor of the inductance change due to the winding condition, the inductance measurement is repeatedly performed at an arbitrary time interval shorter than the change of the winding condition, and the immediately preceding inductance measurement is performed by the successive comparator 6. Compare with the value.

In this case, if the change in the number of turns of the drum 2 or the superconducting coil 1 during the winding work is smooth and the change in the inductance within the inductance measurement time interval is smaller than the decrease in the inductance due to a short circuit of one turn, the inductance is reduced. The successive comparison makes it possible to detect the occurrence of an interlayer short circuit in the superconducting coil 1.

That is, the measured inductance data is compared with the previously measured inductance data, and if the absolute value of the difference between the two inductances is within the preset inductance value range, it is determined that there is no interlayer short circuit, and When the inductance value is equal to or more than the set inductance value, it is determined that the interlayer short circuit has occurred.

In this case, the set value of the inductance change is set to a magnitude less than the absolute value of the value obtained by subtracting the inductance decrease value due to a short circuit of one turn from the maximum inductance increase due to the change in winding condition. If the winding condition changes drastically, the inductance measurement interval may be shortened to satisfy the above condition.

By adopting such a method, the occurrence of the interlayer short circuit of the superconducting coil 1 can be detected in real time, and the rewinding work of the wound superconducting coil 1 for repair is basically unnecessary. Become.

As described above, in this embodiment, the inductance measuring instrument 5 for measuring the inductance of the material of the superconducting conductor 3 wound around the superconducting coil 1 at room temperature and the time of the inductance measured by the inductance measuring instrument 5 are measured. A sequential comparator 6 for calculating a change rate, comparing the time change rate of the inductance with a reference time change rate arbitrarily set in advance, and determining the occurrence of an interlayer short circuit of the superconducting coil 1 based on the comparison result. With superconducting conductor 3
During the winding work to form the superconducting coil 1 by winding a large number of times, when detecting an interlayer short circuit of the superconducting coil 1, the value of the inductance of the superconducting conductor 3 material wound around the superconducting coil 1 at room temperature is This is to determine that an inter-layer short circuit of the superconducting coil 1 has occurred when the value changes by a predetermined value or more within a preset reference time.

Therefore, it becomes possible to reliably detect the occurrence of the interlayer short circuit of the superconducting coil 1 in real time even at the stage of manufacturing the superconducting coil 1 in which the inductance changes (during the winding work).

Further, since it is possible to detect the occurrence of the interlayer short circuit of the superconducting coil 1 during the manufacturing process (during the winding work) of the superconducting coil in which the inductance changes, the wound superconducting coil for repair as in the conventional case can be detected. The rewinding work of No. 1 is basically unnecessary, and the problem of delaying the manufacturing process can be solved.

Further, since it is sufficient to provide only the inductance measuring device 5 and the successive comparator 6, it is possible to detect the occurrence of the interlayer short circuit of the superconducting coil 1 with an extremely simple structure and at a low cost.

The present invention is not limited to the above-described embodiment, but can be carried out in various modifications without departing from the scope of the invention, such as combination with measurement of the total resistance of the superconducting conductor 3.

[0030]

As described above, according to the present invention, the inductance measuring means for measuring the inductance of the superconducting conductor material wound around the superconducting coil at room temperature, and the time variation of the inductance measured by the inductance measuring means. An inter-layer short-circuit determination means for calculating the rate, comparing the time variation rate of the inductance with a reference time variation rate set arbitrarily beforehand, and determining the occurrence of the inter-layer short circuit of the superconducting coil based on the comparison result. , When detecting an interlayer short circuit of the superconducting coil, the value of the inductance of the superconducting conductor material wound around the superconducting coil at room temperature is
It was determined that an inter-layer short circuit occurred in the superconducting coil if it changed more than a certain value within a preset reference time.Therefore, the inductance may change during superconducting coil production (during winding work). It is possible to provide a method and a device for detecting an interlayer short circuit of a superconducting coil that can reliably detect the occurrence of an interlayer short circuit of the superconducting coil even at any stage, with a simple structure and at low cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of an inter-layer short-circuit detecting device for a superconducting coil according to the present invention.

[Explanation of symbols]

1 ... Superconducting coil, 2 ... Drum, 3 ... Superconducting conductor, 4 ...
Measurement leads, 5 ... Inductance measuring device, 6 ... Successive comparator.

Claims (2)

[Claims] 1. A method for detecting an interlayer short circuit of a superconducting coil during winding work for forming a superconducting coil by winding a plurality of superconducting conductors, the method comprising: A method for detecting an inter-layer short circuit in a superconducting coil, characterized in that it is determined that an inter-layer short circuit occurs in the superconducting coil when the value of the inductance changes by a certain value or more within a preset reference time. 2. A device for detecting an inter-layer short circuit of a superconducting coil during winding work for forming a superconducting coil by winding a plurality of superconducting conductors at a room temperature of a superconducting conductor material wound around the superconducting coil. Inductance measuring means for measuring the inductance, calculating the time change rate of the inductance measured by the inductance measuring means, and comparing the time change rate of the inductance with a reference time change rate set in advance, the comparison An inter-layer short-circuit detecting device for a super-conducting coil, comprising: