JP2978637B2 - Quench detection device for superconducting winding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quench detecting device for a superconducting winding for detecting a quench (normal conduction transition) generated in a superconducting winding connected in parallel.

[0002]

2. Description of the Related Art The structure of a conventional quench detecting device for a superconducting winding will be described with reference to FIG. FIG. 8 is a circuit diagram partially showing a conventional quench detection device for a superconducting winding disclosed in Japanese Patent Application Laid-Open No. 61-265806.

In FIG. 8, 1 is an AC power supply, 2 and 3 are lead wires formed of normal conducting wires, 5 is a superconducting winding housed in a cryostat 4 together with liquid helium, and 6 is a cryostat 4 A resistive voltage divider connected between the lead wires 2 and 3 in a close part, 7 is a semiconductor switch having thyristors 8 and 9 connected in anti-parallel, and 10 is a mechanical switch.

A current detector 11 is connected to an end of the superconducting winding 5 and detects a current flowing through the superconducting winding 5.
2 is an amplifier connected to the current detector 11, 13 is a lead connected to an intermediate tap of the resistor divider 6, 14 is a lead connected to an intermediate tap of the superconducting winding 5, 15
Is an isolation amplifier connected to leads 13 and 14, 16
Is the amplifier connected to the isolation amplifier 15, and 17 is the amplifier 1
Phase detectors connected to 2 and 16; 18 is an averaging circuit connected to the phase detector 17; 19 is an input connected to the averaging circuit 18 and an output connected to the gates of the thyristors 8 and 9; It is a gate circuit.

Next, the operation of the above-described conventional superconducting winding quench detecting device will be described. When the superconducting winding 5 is excited by the AC power supply 1, a current Is flows through the superconducting winding 5. This current Is is detected by the current detector 11, amplified by the amplifier 12, and
Supplied to On the other hand, the voltage Vs of the superconducting winding 5 is supplied to the phase detector 17 through the insulating amplifier 15 and the amplifier 16 using the intermediate tap of the superconducting winding 5 and the intermediate tap of the resistance voltage divider 6. Then, the phase detector 17 detects the phase of the voltage Vs of the superconducting winding 5 and the phase of the current Is flowing through the superconducting winding 5, and supplies a signal to the averaging circuit 18.

A conventional quench detection device for a superconducting winding is:
It is configured as described above. The voltage signal Vs and the current signal Is of the superconducting winding 5 are extracted, and the phase difference between them is detected using the phase detector 17 to determine whether or not quench occurs. .

When the superconducting winding 5 is not quenched, since no resistance is generated in the superconducting winding 5, the phase difference between the voltage and the current is 90 degrees. When the superconducting winding 5 is quenched, a resistance is generated in the superconducting winding 5, so that it becomes equivalent to a series circuit of the winding and the resistance, and the phase difference becomes smaller than 90 degrees. That is, by detecting this phase difference, it is possible to determine whether the superconducting winding 5 has quenched.

[0008]

In the conventional quench detecting apparatus for a superconducting winding as described above, the withstand voltage design of an intermediate tap for extracting a voltage signal of the superconducting winding 5 when the voltage of the AC power supply 1 increases. However, there was a problem that it became complicated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a quench detecting device for a superconducting winding capable of detecting a quench of the superconducting winding without taking out a voltage signal of the superconducting winding. The purpose is to obtain.

[0010]

[0011]

SUMMARY OF THE INVENTION The quench detection apparatus of the superconducting winding according to claim 1 of the present invention are those having the following listed means. [1] A first superconducting winding excited by an AC power supply. [2] A second superconducting winding connected in parallel to the first superconducting winding and excited by the AC power supply. [3] First current detecting means for detecting a current flowing through the first superconducting winding. [4] connected to the first current detecting means in the opposite direction,
Second current detecting means for detecting a current flowing through the second superconducting winding. [5] Quench detecting means for detecting quench of the first or second superconducting winding based on outputs of the first and second current detecting means.

A quench detection device for a superconducting winding according to a second aspect of the present invention includes the following means. [1] A first superconducting winding excited by an AC power supply. [2] A second superconducting winding connected in parallel to the first superconducting winding and excited by the AC power supply. [3] First current detecting means for detecting a current flowing through the first superconducting winding. [4] The second current detecting means is connected to the first current detecting means.
Second current detecting means for detecting a current flowing through the superconducting winding of the first embodiment. [5] Balance means for making the inductances of the first and second superconducting windings the same. [6] Quench detection means for detecting the quench of the first or second superconducting winding based on the output of the bridge circuit formed by the first and second current detection means and the balance means.

A quench detecting apparatus for a superconducting winding according to a third aspect of the present invention includes the following means. [1] A first superconducting winding excited by an AC power supply. [2] A second superconducting winding connected in parallel to the first superconducting winding and excited by the AC power supply. [3] Current detection means for detecting a current flowing in the first superconducting winding and detecting a reverse current flowing in the second superconducting winding. [4] Quench detecting means for detecting a quench of the first or second superconducting winding based on an output of the current detecting means.

[0014]

[0015]

In the quench detecting apparatus for a superconducting winding according to the first aspect of the present invention, the first superconducting winding is excited by an AC power supply. In addition, the second superconducting winding connected in parallel to the first superconducting winding is excited by the AC power supply. Further, by the first current detecting means,
A current flowing through the first superconducting winding is detected, and a current flowing through the second superconducting winding is detected by second current detecting means connected in reverse to the first current detecting means. . Then, the quench detecting means detects the quench of the first or second superconducting winding based on the outputs of the first and second current detecting means.

In the quench detecting apparatus for a superconducting winding according to a second aspect of the present invention, the first superconducting winding is excited by an AC power supply. In addition, the second superconducting winding connected in parallel to the first superconducting winding is excited by the AC power supply. Further, a current flowing through the first superconducting winding is detected by first current detecting means,
The current flowing through the second superconducting winding is detected by the second current detecting means connected to the first current detecting means. Still further, the first means is provided by a balancing means.
And the second superconducting winding has the same inductance. Then, the quench detecting means detects the quench of the first or second superconducting winding based on the output of the bridge circuit formed by the first and second current detecting means and the balance means.

In the quench detecting apparatus for a superconducting winding according to a third aspect of the present invention, the first superconducting winding is excited by an AC power supply. In addition, the second superconducting winding connected in parallel to the first superconducting winding is excited by the AC power supply. Further, by the current detecting means,
A current flowing through the first superconducting winding is detected, and a reverse current flowing through the second superconducting winding is detected. Then, the quench detecting means detects the quench of the first or second superconducting winding based on the output of the current detecting means.

[0018]

[Embodiment 1] FIG. 1 shows the configuration of Embodiment 1 of the present invention.
This will be described with reference to FIG. FIG. 1 is a circuit diagram partially showing a first embodiment of the present invention, in which AC power supply 1 to cryostat 4, semiconductor switch 7 to mechanical switch 10 are the same as those of the above-described conventional device. In the drawings, the same reference numerals indicate the same or corresponding parts.

In FIG. 1, 5A and 5B are superconducting windings connected in parallel, and 11A and 11B are superconducting windings 5A.
And a current detection sensor for detecting the current flowing through 5B, 20
Is a comparator whose input side is connected to the minus side of each of the current detection sensors 11A and 11B, and whose output side is connected to the semiconductor switch 7. Note that the plus side of the current detection sensor 11A is connected to the plus side of the current detection sensor 11B, and are connected such that their outputs are in opposite directions.

FIG. 2 is a diagram showing a current detection sensor according to the first embodiment of the present invention. In the figure, 21 is a high-frequency toroidal core, and 22 is a copper wire wound around the high-frequency toroidal core 21. Therefore, the current detection sensors 11A and 11B
Constitutes a Rogowskii coil, and a lead wire of a superconducting winding passes through the center of the high-frequency toroidal core 21. The high-frequency toroidal core 21 has a relative magnetic permeability of 100 or less.

[0021]

Next, the operation of the first embodiment will be described. As described above, the superconducting winding is constituted by the parallel winding of superconducting windings 5A and 5B. When current is supplied to superconducting windings 5A and 5B using AC power supply 1, currents flowing in superconducting windings 5A and 5B are equal if inductances of superconducting windings 5A and 5B are equal. Therefore, the current detection sensors 11A and 11B detect the same signal. That is, since the outputs of the current detection sensors 11A and 11B are connected to be opposite to each other, the signal input to the comparator 20 becomes zero.

Here, consider the case where the superconducting winding 5A is quenched. When the superconducting winding 5A is quenched, a resistance is generated, forming a series circuit of the superconducting winding 5A and the generated resistance. Therefore, the current is smaller and the phase is different as compared with the superconducting winding 5B.

If the levels and phases of the signals detected by the current detection sensors 11A and 11B are different, the comparator 20
Is supplied with a signal of a certain predetermined level. Similarly, when the superconducting winding 5B is quenched, the comparator 2
To 0, a signal of a certain predetermined level is input.

When the superconducting winding 5A or 5B is not quenched, the input signal of the comparator 20 is zero.
, A signal of a certain predetermined level is input, and quenching can be determined.

The current detection sensors 11A and 11B shown in FIG.
By using, it is possible to suppress the power loss. The saturation magnetic flux density of the high-frequency toroidal core 21 is proportional to the current and the reciprocal of the relative magnetic permeability.
Even if the cross-sectional area of 1 is reduced, the magnetic flux density in the toroidal core is not saturated. Further, when the high-frequency toroidal core 21 is used as the toroidal core, the hysteresis loss in the toroidal core is reduced. Note that a high-frequency toroidal core 21 satisfying the above relative magnetic permeability is commercially available.

The superconducting windings 5A and 5B are housed in the cryostat 4 and usually have a current detecting sensor 11
A and 11B are also stored in the cryostat 4. Superconducting windings 5A and 5B are immersed in liquid helium, and current detection sensors 11A and 11B are similarly immersed in liquid helium. Alternatively, it may be installed in low-temperature gas helium. Thus, the higher the loss consumed by Rogowski coils, the higher the consumption of expensive liquid helium. It is desirable that the amount of the iron core used for the core be small.

It is difficult to house the current transformer normally used at room temperature in the cryostat 4 due to restrictions on the outer diameter. In addition, the amount of iron core used is large and the loss is large, which is not economical.

Embodiment 1 of the present invention, as described above,
The current detection sensors 11A and 11B are attached to the superconducting windings 5A and 5B connected in parallel, respectively. The current detection sensors 11A and 11B are connected in opposite directions to the current, and the detection signal is supplied to the comparator 20. Therefore, the semiconductor switch 7 can be shut off even if one of the superconducting windings 5A or 5B quenches. That is, there is an effect that the quench of the superconducting parallel winding can be detected with a simple and inexpensive configuration.

Embodiment 2 FIG. In the above-described first embodiment, it is assumed that the inductances of the superconducting windings 5A and 5B are equal. However, the second embodiment uses the balance resistor 23 to detect a quench even when the inductance is different. .

The configuration of the second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing a main part of a second embodiment of the present invention, and other parts not shown are the same as those of the first embodiment. In the drawings, the same reference numerals indicate the same or corresponding parts.

[0032] In FIG. 3, the bridge is formed by balancing resistor 23 connected in parallel with the current detection sensor 11A and 11B which are connected in series.

The quench detecting means according to the second aspect of the present invention is, for example, a
It corresponds to 0.

Next, the operation of the second embodiment will be described. If the inductances of the superconducting windings 5A and 5B are the same, the current flowing through each becomes the same, and the outputs of the current detection sensors 11A and 11B become the same. However,
If the superconducting windings 5A and 5B have different inductances,
Even when no quench has occurred, the input signal appears in the comparator 20, making it difficult to determine the quench.

Therefore, a bridge is formed using the balance resistor 23, and when the superconducting windings 5A and 5B are not quenched, the balance resistor 23 is adjusted and balanced so that the input signal to the comparator 20 becomes zero. Make quench decisions easier.

Embodiment 3 FIG. As shown in FIG. 4, when the current detection sensor 24 wired so that the currents of the superconducting windings 5A and 5B flow in opposite directions in the Rogowski coil, the Rogowski coil is used when no quench occurs. Is zero. When one of the superconducting windings 5A or 5B is quenched, a difference occurs in the currents flowing through the respective superconducting windings 5A or 5B, and the output of the Rogowski coil becomes non-zero. Therefore, the quench can be detected. The use of the current detection sensor 24 is economical because the number of current detection sensors can be halved.

The current detecting means according to claim 3 of the present invention is, for example, a
The quench detecting means according to claim 3 of the present invention corresponds to the comparator 20 in the third embodiment.

Embodiment 4 FIG. Further, in the first to third embodiments described above, the case where the number of parallel windings of the superconducting winding is two has been described. However, as shown in FIG. 5, the number of parallel windings may be three or more. Not even. FIG.
FIG. 9 is a circuit diagram showing a main part of a fourth embodiment of the present invention.

In FIG. 5, superconducting winding 5A is provided with current detecting sensors 11A and 11D, and superconducting winding 5B
Are provided with current detection sensors 11B and 11E in the same manner, and superconducting winding 5C is provided with current detection sensors 11C and 11E.
F is similarly installed.

As shown in FIG. 6, the quench is detected as one pair using two current detection sensors provided in different parallel windings 5A to 5C, and a total of three pairs are used as a comparator 2
0A, 20B, and 20C, and the outputs of the comparators 20A to 20C are ORed by an OR gate 25. By doing so, the same effect as in the first embodiment can be obtained even if any of the superconducting windings 5A to 5C among the three parallel windings is quenched. If the current detection sensors are shared, the number can be reduced by half.

Embodiment 5 FIG. By the way, in the description of each embodiment described above, the coil has been described, but as shown in FIG.
Needless to say, the same effects as those of the above-described embodiments can be obtained.

[0042]

[0043]

As described above, the quench detection device for a superconducting winding according to the first aspect of the present invention has a first superconducting winding excited by an AC power supply and a parallel connection to the first superconducting winding. A second superconducting winding connected and excited by the AC power supply, a first current detecting means for detecting a current flowing through the first superconducting winding, and a reverse direction to the first current detecting means. A second current detecting means connected to the second superconducting winding for detecting a current flowing through the second superconducting winding;
And a quench detecting means for detecting the quench of the first or second superconducting winding based on the output of the second current detecting means. Quench can be detected,
Further, there is an effect that the quench of the superconducting parallel winding can be detected with a simple and inexpensive configuration.

As described above, the quench detection device for a superconducting winding according to a second aspect of the present invention is configured such that the first superconducting winding excited by the AC power supply is connected in parallel to the first superconducting winding. A second superconducting winding excited by the AC power supply, a first current detecting means for detecting a current flowing through the first superconducting winding, and a second superconducting winding connected to the first current detecting means; Second current detecting means for detecting a current flowing through the second superconducting winding, balance means for making the inductances of the first and second superconducting windings equal, and the first and second currents Quench detection means for detecting the quench of the first or second superconducting winding based on the output of the bridge circuit formed by the detecting means and the balance means, so that the voltage signal of the superconducting winding is taken out. It not, it is possible to detect the quenching of the superconducting winding, also, the inductance of the first and second superconducting winding an effect that can detect quench even if different.

As described above, the quench detection device for a superconducting winding according to a third aspect of the present invention is configured such that the first superconducting winding excited by the AC power supply is connected in parallel to the first superconducting winding. A second superconducting winding excited by the AC power supply, and current detecting means for detecting a current flowing in the first superconducting winding and detecting a reverse current flowing in the second superconducting winding, Quench detecting means for detecting the quench of the first or second superconducting winding based on the output of the current detecting means, so that the quench of the superconducting winding can be performed without taking out the voltage signal of the superconducting winding. It can be detected, and the number of current detecting means can be halved, which is economical.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a current detection sensor according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a main part of a second embodiment of the present invention.

FIG. 4 is a diagram showing a current detection sensor according to a third embodiment of the present invention.

FIG. 5 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 6 is a diagram illustrating connection of a current detection sensor according to a fourth embodiment of the present invention.

FIG. 7 is a circuit diagram showing a fifth embodiment of the present invention.

FIG. 8 is a circuit diagram showing a conventional quench detection device for a superconducting winding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 5A, 5B Superconducting winding 5C, 5D Superconducting winding 7 Semiconductor switch 11A, 11B, 11C, 11D Current detection sensor 11E, 11F, 11G, 11H Current detection sensor 20 Comparator 20A, 20B, 20C Comparator 24 Current detection sensor 25 OR gate

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01F 6/00 ZAA H01F 6/02 ZAA

Claims (3)

(57) [Claims] 1. A first superconducting winding is excited by an AC power source, connected in parallel to the first superconducting winding, a second superconducting coil to be excited by said AC power source, the first
Current detecting means for detecting the current flowing through the superconducting winding of
Stage, connected in reverse to said first current sensing means,
A second current detection for detecting a current flowing through the second superconducting winding;
Detecting means, as well as superconducting, characterized in that it comprises a quench detection means for detecting a quenching of said first or second superconducting windings on the basis of the output <br/> of the first and second current detection means Winding quench detection device. 2. A first superconducting winding excited by an AC power supply, a second superconducting winding connected in parallel to the first superconducting winding and excited by the AC power supply,
First current detecting means for detecting a current flowing through the superconducting winding, this is connected to the first current detecting means, a second current detecting means for detecting a current flowing through the second superconducting winding,
The first and second superconducting windings have the same inductance.
Balancing means to be a, and is formed from the first and second current detection means and said balancing means
A quench detecting device for detecting a quench of the first or second superconducting winding based on an output of the bridge circuit . 3. A first superconducting winding excited by an AC power supply, a second superconducting winding connected in parallel to the first superconducting winding and excited by the AC power supply,
The life and death detecting a current flowing through the superconducting winding second super conductive
Current detecting means for detecting a reverse current flowing through the conductive winding, and quench detecting means for detecting a quench of the first or second superconducting winding based on an output of the current detecting means. Quench detection device for superconducting windings.