JPH0513222A - Superconducting coil device - Google Patents

Abstract

PURPOSE:To obtain a device wherein a continuous operation can be executed by a large DC electric current, the large DC electric current is cut off surely and can be shifted to a protective resistance when an abnormality such as a quenching action or the like is caused and a high-efficiency protective device is provided by a method wherein a DC breaking device is connected in parallel with the protective resistance and a control device performing a specific action is installed. CONSTITUTION:A superconducting coil device is provided with the following: a superconducting coil 2 to which a DC electric current is supplied from an excitation power supply 6 via a first switching device 5; and a protective resistance 3 connected in parallel with the superconducting coil 2. When the abnormality of the superconducting coil 2 is caused, an energy stored in the superconducting coil 2 is consumed by the protective resistance 3. In the superconducting device, a DC breaking device 4 is connected in parallel with the protective resistance 3. In addition, a control device 7 wherein the DC breaking device 4 is normally set to a closed state, it is closed when an abnormality is caused, a superconducting coil current is shifted to the DC breaking device 4, the first switching device 5 is then opened and, after that, the DC breaking device 4 is opened is installed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various superconducting coil devices such as a nuclear fusion device, an accelerator and a superconducting energy storage device. In particular, the load on the superconducting coil device is in an abnormal state such as normal conduction transition (quenching). The present invention relates to a protection device for when the fish is lit up.

[0002]

2. Description of the Related Art Recently, applications of superconducting coil devices are rapidly spreading in various fields such as nuclear fusion devices, accelerators, and superconducting energy storage devices. The superconducting coil normally has an electric resistance of zero in the superconducting state, but may change from the superconducting state to the normal conducting state due to a sudden change in the magnetic field or an abnormal temperature. The phenomenon in which the superconducting state is destroyed is called quenching. When this quenching occurs, however, there is a risk that the pressure will increase due to abnormal evaporation of liquid helium or the like.

Therefore, as shown in FIG. 4, in the superconducting coil 2 supplied with electric power from the AC / DC converter 6 as the excitation power source, the protective resistor 3 is connected in parallel with the superconducting coil 2 to cause quench. In this case, a method is adopted in which the energy stored in the superconducting coil 2 is consumed by the protective resistor 3 and the expansion of the quench is suppressed to protect the superconducting coil 2. That is, when a quench occurs, the superconducting coil current flowing in the loop circuit composed of the AC / DC converter 6 and the superconducting coil 2 is shifted to the protective resistor 3, but at this time, a DC interruption is performed to interrupt a large DC current. Device 4
Is required. Particularly in recent years, the size of the superconducting coil device has been increasing, and the current flowing through the superconducting coil 2 has tended to increase, and the number of superconducting coil devices aiming for continuous operation is increasing. On the other hand, if a quench etc. occurs in the super electric coil,
Since a high voltage is generated, the above DC interrupting device 4 used for quench protection must be a high voltage interrupting device capable of interrupting a large DC current and capable of continuous operation.

However, in general, a high voltage type DC interrupting device can handle only a small current, while a DC interrupting device capable of handling a large current is a low voltage type. Therefore, one DC breaker cannot withstand continuous high-current energization, and a plurality of high-voltage DC breakers 4A to 4N are connected in parallel as shown in FIG. A conventional device of this type is disclosed in, for example, Japanese Patent Laid-Open No. 57-198613.

However, in the conventional device shown in FIG. 5, since a plurality of high-voltage type DC circuit breakers are required, not only is it extremely expensive as a protective device,
There is a problem that the installation space also increases. Further, it is difficult to simultaneously disconnect a plurality of DC interrupting devices connected in parallel, and there is also a problem that the DC interrupting device itself and circuit components are damaged due to failure in interrupting due to variations in interrupting operation timing.

Therefore, a DC cutoff method as shown in FIG. 6 has been proposed recently. That is, the DC circuit breaker 4 is connected in parallel with the series circuit of the small resistor 10 and the switch device 11, and when the superconducting coil 2 is excited by the AC / DC converter 6, the DC circuit breaker 4 is in the open state. Switchgear 11
Is closed, and when the superconducting coil current is interrupted by the occurrence of quench in this condition, the DC interrupting device 4
Is closed first, and the series circuit of the small resistor 10 and the switchgear 11 is short-circuited so that the superconducting coil current is almost completely cut off by the DC breaker 4.
After that, the switchgear 11 is opened, and finally the DC interrupter 4 is opened so that a large DC current can be interrupted. As a known example of this type, there is JP-A-1-40409.

In addition, Japanese Patent Laid-Open No. 58-95803 discloses a device in which a series circuit of a switch and a capacitor is connected in parallel with a superconducting coil or a protective resistor. However, this switch is turned on at the time of quench to connect the capacitor in parallel with the protection resistor so that the surge voltage that is generated due to the inductance of the protection resistor is absorbed by the capacitor and the excitation power supply is short-circuited. However, it does not fulfill the function of shifting the superconducting coil current to the series circuit of the switch and the capacitor to interrupt it.

[0008]

In the direct current interruption system shown in FIG. 6, the switchgear 11 is provided with a continuous energizing function, and the direct current interruption device 4 is provided with an interruption function when an abnormality such as a quench occurs. Therefore, the high voltage type DC circuit breaker 1
Quench protection is possible on the platform. However, in order to shift the superconducting coil current from the switchgear 11 to the DC breaker 4 by closing the DC breaker 4 at the time of DC cutoff, it is necessary to provide the minute resistor 10 in series with the switchgear 11, so that continuous energization is performed. Time, that is, this small resistor 1
There is a problem in that the efficiency loss is reduced by the amount of jyuru loss caused by zero. Therefore,
An object of the present invention is to provide a superconducting coil device capable of continuous operation with a large DC current, capable of reliably blocking the large DC current and shifting to a protective resistor when an abnormality such as a quench occurs, and having a highly efficient protective device. To provide.

[0009]

In order to achieve the above object, the present invention relates to a superconducting coil which is supplied with DC power from an exciting power source through a first switchgear, and is connected in parallel with the superconducting coil. In a superconducting coil device in which the protection resistor consumes energy accumulated in the superconducting coil when an abnormality such as quench of the superconducting coil occurs, connect a DC circuit breaker in parallel with the protection resistor. Then, this DC interrupting device is normally opened, and when an abnormality such as a quench occurs, it is closed to shift the superconducting coil current from the exciting power source to the DC interrupting device,
After that, a control device is provided which opens the first switchgear and then opens the DC interrupting device.

[0010]

The present invention is constructed as described above, and since the DC interrupting device is normally open, the first switching device can be continuously energized, and the exciting power source,
For example, a semiconductor element that constitutes an AC-DC converter has a forward voltage drop even when it is conducting.Therefore, when an abnormality such as a quench occurs, the DC cutoff device is closed to use the voltage drop to superconduct. The coil current can be shifted from the excitation power source to the DC interrupting device, and then the first switching device can be opened and then the DC interrupting device can be opened to interrupt the superconducting coil current and shift it to the protective resistor. .

[0011]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a circuit diagram of a superconducting coil device showing an embodiment of the present invention. In FIG. 1, 2 is a superconducting coil equipped with a quench detector 1, 3 is a protective resistor, 4 is a direct-current interruption device, which are connected in parallel with each other, and further in parallel with these parallel circuits. Switchgear 5
A serial circuit of the AC / DC converter 6 is connected, and a control device 7 for controlling each of the above components is provided.
The DC breaker 4 may be composed of a DC breaker alone, or a DC commutator circuit (consisting of a capacitor, a reactor and a starting switch) for creating a current zero point at DC break and a DC breaker alone are connected in parallel. It may be configured by connecting. The AC / DC converter 6 is composed of a semiconductor element, is connected between the AC power system and the superconducting coil 2, and serves as a power source for injecting energy into the superconducting coil 2 and releasing energy from the superconducting coil 2 into the AC power system. To work.

In the superconducting coil device thus constructed, the first switchgear 5 is closed during normal operation.
The DC interrupting device 4 is in an open state, the superconducting coil 2 stores energy in the form of magnetic energy, while the AC / DC converter 6 injects energy into the superconducting coil 2 and transfers energy from the superconducting coil 2 to the AC power system. It is releasing.

Now, if a quench occurs in the superconducting coil 2, this is detected by the quench detector 1, and the detection signal is sent to the control device 7, and the control device 7 receives the detection signal and quenches. Outputs a linked operation command corresponding to protection to each component. First, the AC / DC converter 6
Then, in response to a command from the control device 7, the bypass pair operation in which the AC / DC converter 6 itself is short-circuited is started, but even if this bypass pair operation is entered, the semiconductor elements constituting the AC / DC converter 6 are forwardly forwarded. There is a voltage drop (FVD) in the device and also a voltage drop due to a wiring bus in the panel, etc., so that a voltage of several volts or more is generated between the output terminals of the AC / DC converter 6. Next, the DC interrupting device 4 is closed, and thereby the AC / DC converter 6 is short-circuited, so that the superconducting coil current flowing through the AC / DC converter 6 is shifted to the DC interrupting device 4.
Here, after the first switchgear 5 is opened, the DC interrupter 4 is opened, so that the superconducting coil current is interrupted and shifted to the protective resistor 3, which is consumed as jule heat. Expansion can be suppressed.

According to the present embodiment, the DC interrupting device 4 for interrupting the superconducting coil current at the time of occurrence of a quench may be of a short-time rating, so that it is possible to interrupt the DC of a large current. Since the voltage drop of the AC / DC converter 6 is utilized, a microresistor is not required as in the conventional example shown in FIG. The efficiency can be improved. The value of the superconducting coil current is several + kA
As long as the application of this embodiment is possible, a single DC circuit breaker can be used, and when a plurality of DC circuit breakers are used as in the conventional example shown in FIG. It is also possible to solve problems such as interruption failure due to variations in operation timing.

FIG. 2 is a circuit diagram of a superconducting coil device showing another embodiment of the present invention. In this embodiment, in addition to the embodiment of FIG. 1, a DC current detector 8 is further arranged in series with the DC interrupting device 4. This DC current detector 8
Mainly detects the superconducting coil current that is shifted from the AC / DC converter 6 to the DC interrupting device 4 after the DC interrupting device 4 is closed. The detection signal is sent to the control device 7 and its value is When the voltage reaches a predetermined level or higher, the control device 7 outputs an open circuit command to the first switching device 5. Therefore, the first switchgear 5 does not need to turn off the residual DC current more than necessary, and the damage to the electrode can be suppressed.

FIG. 3 is a circuit configuration diagram of a superconducting coil device showing still another embodiment of the present invention. In this example,
In addition to the embodiment of FIG. 1, a second switchgear 9 is further arranged in series with the protective resistor 3. The second switchgear 9 is open during normal operation, but when a quench occurs, the second switchgear 9 is closed immediately before the DC interrupting device 4 is opened by a closing command from the controller 7. Therefore, it is possible to suppress the jule loss in the protection resistor 3 due to the current from the AC-DC converter 6, and improve the efficiency of the entire device.

[0018]

As described above, according to the present invention, the first switchgear has the continuous energizing function, and the DC interrupting device has the superconducting coil current interrupting function when an abnormality such as a quench occurs. Therefore, it is only necessary to use the DC breaker with a short-time rating, so that the DC cutoff of a large current can be reliably performed, and the superconducting coil current can be shifted to the protection resistor to protect the superconducting coil. Moreover, since the voltage drop of the excitation power supply was used to shift the superconducting coil current to the DC interrupting device due to the closed circuit of the DC interrupting device, it is not necessary to use a minute resistor as in the conventional case. The jule loss that is always generated by this minute resistor is eliminated, and the efficiency of the entire device can be improved.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a superconducting coil device showing an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a superconducting coil device showing another embodiment of the present invention.

FIG. 3 is a circuit configuration diagram of a superconducting coil device showing still another embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a conventional superconducting coil device.

FIG. 5 is a circuit configuration diagram of another conventional superconducting coil device.

FIG. 6 is a circuit configuration diagram of still another conventional superconducting coil device.

[Explanation of symbols]

1 Quench detector 2 Superconducting coil 3 protection resistors 4 DC breaker 5 First switchgear 6 AC / DC converter 7 Control device 8 DC current detector 9 Second switchgear

Claims (3)

[Claims] 1. A superconducting coil supplied with DC power from an excitation power source via a first switchgear, and a protective resistor connected in parallel with the superconducting coil. When an abnormality occurs in the superconducting coil. In a superconducting coil device in which the energy stored in the superconducting coil is consumed by the protective resistor, a DC interrupting device is connected in parallel with the protective resistor, and the DC interrupting device is normally opened. A superconducting coil device, which is provided with a control device for closing the circuit when an abnormality occurs to shift the superconducting coil current to the DC circuit breaker and then opening the first switchgear and then opening the DC circuit breaker. . 2. The direct current detector according to claim 1, further comprising a direct current detector for detecting the magnitude of the superconducting coil current shifted to the direct current interruption device when an abnormality occurs, wherein the control device includes the direct current detector. A superconducting coil device, wherein the superconducting coil device is configured to output a command to open the first switchgear when the current value detected in 1 reaches a predetermined value or more. 3. The device according to claim 1, wherein a second switchgear is connected in series with the protection resistor, and the controller keeps the second switchgear in an open circuit state in a normal state, A superconducting coil device, which is configured to output a command to close the DC circuit breaker prior to opening the circuit when an abnormality occurs.