JPH0332292B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an energy storage device suitable for supplying power to a device that consumes power intermittently, such as a poloidal coil of a nuclear fusion experimental device or a neutral particle injection device.

FIG. 1 shows an example of a conventional energy storage device.

In FIG. 1, 1 is a DC power source, 2 is a superconducting coil for storing energy, 3 is a wire cutter, and 4 is a resistor. In this figure, the broken line represents a superconducting container, usually a cryostat, and the coil 2 becomes superconducting by being cooled to an extremely low temperature in this superconducting container (the same applies to FIGS. 2 and 4, which will be described later). ).

In FIG. 1, when the DC power supply 1 causes a current to flow through the coil 2 with the breaker 3 turned on, approximately 1/2 LI ² of energy is stored in the coil 2. Here, L is the inductance of the coil 2, and I is the flowing current value. In particular, when the coil 2 exhibits superconducting characteristics, its resistance becomes very small, so it is common to set both L and I to large values, and the stored energy becomes very large.

On the other hand, when the superconducting properties are no longer maintained for some reason, the resistance of the coil 2 increases rapidly, so the flowing current must be reduced immediately. In the configuration shown in FIG. 1, a series circuit of a coil 2 and a resistor 4 is created by disconnecting a shield breaker 3, and the current flowing through this circuit is connected to a resistor 4.
This is intended to absorb and reduce energy as Joule heat generated by the resistance of the coil 2.

In this case, when the circuit breaker 3 is disconnected, the current I flowing through the circuit will flow through the resistor 4.
If the resistance of the resistor is R, a voltage of RI will be generated across the resistor 4, that is, across the coil 2.

From this, if the resistance value R of the resistor 4 is increased, the current decreases faster, but the voltage generated between both ends of the coil 2 increases, and the potential to the winding frame, superconducting container, etc., that is, the ground potential, also increases. Rise. Therefore, it becomes difficult to insulate the coil 2, and it becomes expensive.

In view of the prior art as described above, the present invention seeks to provide an energy storage device that quickly absorbs energy stored in a superconducting coil without increasing the insulation strength of the superconducting coil.

FIG. 2 shows an embodiment of the present invention. In this figure, 1 and 3 are a DC power supply and a breaker, as in the case of FIG. The superconducting coil is 2
A and 2b, and the resistor is made up of 4a and 4b. 5a and 5b are cutters and disconnectors, and 6 is a charger. It is assumed that the coils 2a and 2b are in a superconducting state, and the shield breakers 5a and 5b are placed near them.

The operation of this embodiment having the above configuration is as follows. That is, when the superconducting properties are no longer maintained for some reason and it is desired to absorb the energy stored in the coils 2a and 2b immediately, first, the input device 6 is turned on.
Cut the cutter 3. Next, the breaker 5a,
When 5b is cut off, the current I flowing through the coil is
It flows along the route 2a → 4a → 2b → 4b → 6 → 2a.

That is, the voltages generated in the coils 2a and 2b are determined by the voltages generated in the resistors 4a and 4b. For example, if the coils 2a and 2b are equal,
If the resistors 4a and 4b are made equal, the coils 2a,
The voltages V _2a and V _2b generated in resistors 2b are approximately equal, and they are the voltages generated in resistors 4a and 4b.
Both V _4a and V _4b are approximately equal. That is, coil 2
The voltage across the pair of resistor a and resistor 4a is approximately zero. FIG. 3 schematically shows the voltage change during this period.

Generally, if n coils and resistors are connected alternately in series as shown in Figure 2, the total resistance value of the n resistors will be n times the resistance value R of one resistor. The maximum voltage generated in each coil is determined by the resistance value R of one resistor.

In this way, the energy stored in the coil can be quickly absorbed without increasing the insulation strength of the coil.

Next, let us consider the structure of the energy storage device in more detail with respect to the coils 2a, 2b, resistors 4a, 4d, and shimmer cutters 5a, 5b in FIG. 2.

FIG. 4 is an example of the configuration of a main part of an energy storage device according to another embodiment. In Fig. 4, 7 is a bridge or disconnector, 8 is a commutating capacitor, and 9 is a commutating capacitor 8.
The charging device 10 is an input switch, and the other configurations are the same as in FIG. 2. In FIG. 4, the shield breaker 5b may be a vacuum shield, a conductor, or the like, but here, a vacuum shield using a superconducting conductor is taken as an example. FIG. 5 shows a cross-sectional view of a vacuum valve that forms a vacuum section of the vacuum section. In FIG. 5, 11 is a fixed conductor, 12 is a movable conductor, 13 is a bellows, 14 is a vacuum container, 1
15 is a fixed side contact, and 16 is a movable side contact. In FIG. 5, by making the fixed side and movable side conductors 11 and 12 superconducting, the shingle breaker can have a very small resistance component. In FIG. 4, if a vacuum shield breaker 5b using such a superconducting conductor is used, the coil 2 in a superconducting state can be removed.
The energization state of a and 2b results in extremely low resistance loss.

In the embodiment shown in FIG. 4, during the shearing operation,
By opening the line breaker 5b and turning on the closing switch 10, the line breaker 5b is disconnected by the discharge current from the commutating capacitor 8 previously charged by the charging device 9, and the current is transferred to the resistor. It becomes possible to make it commutate to 4a.

In addition, the shield breaker 7 is inserted before the opening operation of the shield breaker 5b, and the current is commutated to the shield breaker 7 by the arc voltage generated when the shield breaker 5b is opened.
Thereafter, it is also possible to turn on the closing switch 10, to cause the discharge current from the commutating capacitor 8 to cut off the breaker 7, and to cause the commutated current to flow through the resistor 4a again. In this case, the sheath breaker 5b placed in the superconducting vessel has completed shearing due to current commutation earlier, so it is characterized by being free from various phenomena during the shearing break. be.

On the other hand, by providing the resistor 4a in FIG. 4 with non-linearity in the resistance value R as shown in FIG. It is possible to maintain the voltage given by the product RI and I at an approximately constant value as shown in FIG. In this case, since the insulation strength is determined by a substantially constant voltage value, it is possible to reduce the current I flowing through the coil 2a etc. having a given insulation strength more quickly.

As the resistance value 4a having such nonlinearity, for example, a nonlinear resistance element such as a current limiting line whose resistance value rapidly increases due to the heat generated by the current flowing through the resistor 4a itself can be considered.

In general, increasing the insulation strength of a coil in a superconducting state is expensive, so the ability to absorb energy without increasing the insulation strength of the present invention is highly economical and highly reliable. This will increase the

As explained above, according to the present invention, an energy storage device that can quickly absorb energy stored in a superconducting coil without increasing the insulation strength of the superconducting coil and is also economically efficient can be realized.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an example of a conventional energy storage device, Fig. 2 is a circuit diagram showing an embodiment of the present invention, Fig. 3 is an explanatory diagram of the operation of Fig. 2, and Fig. 4 is a circuit diagram showing an embodiment of the present invention. A partial circuit diagram showing another embodiment, FIG. 5 is a sectional view of a vacuum valve used as an embodiment of a cutter, and FIG. 6 is an explanatory diagram of the operation of a resistor. 2a, 2b... superconducting coil, 4a, 4b...
Resistor, 5a, 5b...Shiya breaker.

Claims (1)

[Claims of Claims] 1 A plurality of units in which a direct current power source, a shingle breaker, and a energizer are connected in series, and a parallel structure of a resistor and a shingle breaker are connected in series to a superconducting coil for energy storage are connected in series. An energy storage device characterized in that a series structure connected to the input device is connected in parallel between terminals of the input device. 2. A unit is a unit in which a shield breaker housed in a superconducting container is connected in parallel with a shield breaker and a resistor in a normal conducting state, and the parallel structure and a superconducting coil are connected in parallel. An energy storage device according to claim 1, characterized in that: 3 As a breaker housed in a superconducting container,
3. The energy storage device according to claim 2, wherein the energy storage device employs a vacuum breaker using a superconducting conductor. 4. A resistor has a nonlinear property in which its resistance value increases over time when current begins to flow, and the rate at which the flowing current decreases and the rate at which the resistance value increases are approximately the same, and the voltage at both ends remains constant for approximately a period of time. The energy storage device according to claim 1, characterized in that the energy storage device has a characteristic of maintaining a constant value.