JPH04211105A - Superconducting apparatus, superconducting energy storing apparatus and operating method therefor - Google Patents

Abstract

PURPOSE:To provide a superconducting apparatus which can open a permanent current switch at quite high speed and a highly efficient superconducting energy storing apparatus which can instantaneously accommodate for system disturbance with substantially no energy loss. CONSTITUTION:The invention comprises a superconducting apparatus having a permanent current switch 1, which opens upon conduction of a current higher than a critical level, connected in parallel with a superconducting coil 3 and a superconducting energy storing apparatus at least provided with a function for opening the permanent current switch 1, which has been closed in order to feed a permanent current to the superconducting coil 3, upon conduction of a current higher than a critical level at a time point when the superconducting coil 3 is stored with set energy through an exciting power supply 7.

Description

[Detailed description of the invention]

[0001]

[Field of Industrial Application] The present invention relates to a superconducting device, a superconducting energy storage device, and a method of operating the same, and in particular, after storing a set energy in a superconducting coil, a persistent current switch is connected in parallel with the superconducting coil. The present invention relates to a superconducting device, a superconducting energy storage device, and a method of operating the same, which are suitable for a device in which a permanent current continues to flow through a superconducting coil. [0002]

2. Description of the Related Art In order to become superconducting, it is essential that the three conditions of temperature, magnetic field, and current be below the critical temperature, critical magnetic field, and critical current, respectively. [0003] Conventional techniques related to persistent current switches usually open and close the persistent current switch by mainly controlling temperature and magnetic field among the above three conditions. There are also mechanical types of persistent current switches, which are
By mechanically contacting and separating superconducting wires,
It operates to close and open circuits. However, this method
Due to the problem of high contact resistance, there is currently little progress in development.

On the other hand, a persistent current switch to be applied to a superconducting energy storage device for system stabilization is required to have a high-speed opening/closing function since the system disturbance phenomenon lasts several seconds or less. Therefore, since the persistent current switch of the current state of the art cannot cope with this problem, a thyrisk switch that simulates a persistent current switch is installed in the room temperature region, and the high-speed opening/closing function is entrusted to the thyrisk switch. [0005] Japanese Patent Application Laid-Open No. 62-93987 is cited as related to this type of device. Further, regarding a thermal switch, there is a disclosure in Japanese Patent Laid-Open No. 111381/1981. [0006]

[Problem to be Solved by the Invention] In the above-mentioned conventional technology, whether the thermal type or the magnetic field type, the opening/closing speed of the persistent current switch is slow, on the order of several tens of seconds, and the problem with system disturbances is that the phenomenon ends in a few seconds or less. It has been inherently difficult to apply it to superconducting energy storage devices used for stabilization. For this reason, superconducting energy storage devices for power grid stabilization use semiconductor switches such as thyristors to increase the opening and closing speed. However, during the so-called energy storage period when there is no grid disturbance, the semiconductor switches There was a contradictory problem in that the stored energy gradually attenuated due to the forward voltage drop. [0007] The present invention has been made in view of the above points,
The aim is to create a superconducting device that can open persistent current switches extremely quickly, and a superconducting energy storage device that can instantly respond to grid disturbances and has extremely high efficiency with almost no loss of stored energy. ,
and its operating method. [0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a superconducting device, an excitation power source, and a superconducting device in which a current-type persistent current switch is installed in parallel with a superconducting coil and operates to open the circuit when energized at a critical current value or higher. A superconducting energy storage device having at least the function of a persistent current switch, which is closed in order to cause a persistent current to flow through the superconducting coil, to open the circuit when a current exceeding a critical current value is applied when a set energy is stored in the superconducting coil. , in series with a thermal type or magnetic field type persistent current switch that is closed in order to cause a persistent current to flow through the superconducting coil when the set energy is stored in the superconducting coil by the excitation power source, and is opened when the current exceeds the critical current value. A superconducting energy storage device connected to an operating current-type persistent current switch, the persistent current switch being closed in order to cause a persistent current to flow through the superconducting coil when the set energy is stored in the superconducting coil by an excitation power source, A superconducting energy storage device that is connected in parallel with a superconducting coil, which has characteristics that are controlled to open and close automatically or magnetically, and characteristics that the circuit is opened when the current exceeds a critical current value and is closed with a transient thermal time constant. With the persistent current switch open, energy is stored in the superconducting coil by exciting it with an excitation power source connected to the power system, and when this stored energy reaches a set value, the persistent current switch is closed. At the same time, when the excitation power supply is stopped and a persistent current continues to flow through the superconducting coil, and when an operation command for system stabilization is received from the power system while the persistent current is flowing through the superconducting coil, A superconductor in which the persistent current switch is energized with a current equal to or higher than a critical current value to perform a circuit opening operation, and the energy stored in the superconducting coil is taken out to the system side of the excitation power supply only for the time until the circuit is reclosed. This is a method of operating an energy storage device. [0009]

[Operation] The excitation power source is used to input and output the stored energy of the superconducting coil. In this case, when the superconducting coil is initially charged with energy, the conventional thermal type or magnetic field type persistent current switch is opened. Once the set energy is stored in the superconducting coil, the thermal type,
Alternatively, the magnetic field type persistent current switch is operated to close the circuit to stop the excitation power source. By this operation, a persistent current continues to flow through the superconducting coil, resulting in an energy storage state by a so-called superconducting energy storage device. In this state, if the power system issues an operation command to the superconducting energy storage device to stabilize the system, the pulse power source connected in parallel with the excitation power source is driven, and the current type persistent current according to the present invention is activated. A current higher than the critical current value is applied to the switch, and the circuit is opened at high speed. Through this operation, the superconducting coil and the excitation power source are electrically connected, and energy can be transferred between the superconducting energy storage device and the power system. However, since the grid stabilization operation only takes a few seconds or less, the re-closing timing of the current-type persistent current switch also suffices within this time period. This is possible by designing it in such a way. If the current type persistent current switch is reclosed, the state of energy storage by the superconducting coil will be reproduced. Further, when the superconducting energy storage device is stopped, it is done by opening a thermal type or magnetic field type persistent current switch. [00101

[Embodiments] The present invention will be explained in detail below based on the illustrated embodiments. The example described below is for a superconducting energy storage device. FIG. 1 shows an embodiment of the present invention. [0012] As shown in the figure, in this embodiment, a current type persistent current switch (hereinafter, PC
(abbreviated as Sl) 1, and a thermal type or magnetic field type persistent current switch (hereinafter referred to as P) controlled by critical temperature, critical magnetic field, etc.
(abbreviated as C82) 2 are connected in series, which are connected in parallel to the superconducting coil 3, and both are installed in the cryostat. Further, an external circuit constituted by a series circuit of a capacitor 5 and a thyrisk switch 6 is connected in parallel to the superconducting coil 3 in order to supply a current higher than the critical current value to the PC 81. Furthermore, an excitation thyristor converter 7 connected in parallel to the superconducting coil 3 is provided, and the AC side of the excitation thyristor converter 7 is connected to a power system 8 to constitute a superconducting energy storage device. Next, a method of operating the superconducting energy storage device of this embodiment will be explained. [0013] First, the PC 82 is brought into an open state by heating it with a heater or by applying a magnetic field. PC
81 is naturally in a closed state because no current is flowing through it yet. Next, by driving the excitation thyristor converter 7, a DC current is applied to the superconducting coil 3, and when the set value is reached, the PC 82 is returned to the closed circuit state, and the excitation thyristor converter 7 is gate-blocked. . By this operation, the current of the superconducting coil 3 is clamped by PC3L and PC82, and the set energy storage state is achieved (see arrow 9). Incidentally, the rated current value is set in advance to about 60 to 80% of the critical current value of the PC 81. [0014] In the above state, if a disturbance occurs in the power system 8, first, the si-risk switch 6 is turned on based on an operation request from the power system 8. Since the capacitor 5 is charged in advance to a set value, and the excitation thyristor converter 7 is gate-blocked, this operation causes the discharge current to form the discharge path shown by the arrow 10, and the PC
It will flow into 8I, PC82, and superconducting coil 3. However, the series circuit impedance of PC3L and PC32 is much smaller than the impedance of the superconducting coil 3, and as a result, most of the discharge current is
The current flows into the 82 circuit and is superimposed on the current of the superconducting coil 3 which was in the storage state. As a result, the PC 81 is energized to a value equal to or higher than the critical current value, quenches, and becomes an open circuit state. [0015] Since the impedance of the PC8I and PC82 circuits is extremely low as described above, the capacitor 5 can achieve sufficiently high speed and large current discharge with a small size. Furthermore, since current is injected into the superconducting coil 3 in the opposite direction to the current direction in the storage state, quenching does not occur due to this discharge. Now, with PC81 in an open state, there is a PC between the terminals of superconducting coil 3.
A transient voltage is generated based on the resistance component generated at 81. However, since this transient voltage becomes a forward voltage for the excitation thyristor converter 7, the opening of the PC 31 acts in a direction that makes it easier to restart the excitation thyristor converter 7, so the current in the superconducting coil 3 decreases. is commutated to the excitation thyristor converter 7 side at high speed, and as a result, it becomes possible to power back the magnetic energy stored in the superconducting coil 3 to the power system 8 side at high speed. System stabilization operation via the excitation thyristor converter 7 is as follows:
At most, the transient thermal time constant of PC31 is set to several seconds or more, so after the system stabilization operation, PC8
1 automatically returns to the closed circuit state and returns to the original energy storage state again by the gate block of the excitation thyristor converter 7. [0016] FIG. 2 shows another embodiment of the present invention, in which the functions of the PC 32 are added to the PC 81 in FIG. 1, and one persistent current switch 1- is used to perform initial charging. This is used to perform switching and switching for system stabilization operation. The driving operation is substantially the same as that in FIG. 1, so the explanation will be omitted. [0017] By doing as in this embodiment, the current flowing through the superconducting coil is clamped by the persistent current switch during a period when no disturbance occurs in the power system (standby period), so that the stored energy is It is possible to realize an extremely efficient superconducting energy storage device for system stabilization with almost no loss. In addition, if a disturbance occurs in the power system, the persistent current switch is energized to a level exceeding the critical current value by discharging a capacitor installed in the main circuit of the superconducting energy storage device, and is brought into an open state at an extremely high speed. In addition, due to the transient thermal time constant of the persistent current,
Since it can automatically reclose after a set time, it is ideal as a superconducting energy storage device for system stabilization. [0018] FIG. 3 shows a third embodiment of the present invention, and the basic feature is that, in addition to the embodiment shown in FIG. That is. [0019] In this embodiment, first, in order to excite the superconducting coil 3, the switching means 11 is closed, the PC 81 is closed,
This is performed by keeping the PC 82 open and operating the excitation thyristor converter 7. Then, when the current value of the superconducting coil 3 reaches the set current, the PC 32 is closed to shift to persistent current mode operation, the excitation thyristor converter 7 is gate-blocked, and the switching means 11 is opened. With this series of operations, the superconducting energy storage device enters the energy storage state. [00201 Next, consider a case where grid stabilization operation is performed in response to a request from the power grid 8. In this case, first, PC8
It is necessary to open circuit 1 by driving an external power supply (a series circuit of capacitor 5 and thyrisk switch 6). PC
Since the circuit 81 has a characteristic of being opened when a current exceeding a critical current value is applied, a relatively large charging voltage may be required if the external power supply is a capacitor bank, for example. However, since the switching means 11 is open-circuited, no voltage is directly applied to the excitation thyristor converter 7. On the other hand, a voltage detector 1 installed in parallel with the superconducting coil 3 detects the point in time when the discharge current 10 becomes sufficiently large and the charging voltage value of the external power supply (capacitor bank) becomes small.
2, confirm that the voltage is lower than the withstand voltage of the excitation voltage, and give an ON command to the switching means 11 to deblock (restart) the excitation thyristor converter 7, and the superconducting coil The current of No. 3 is shifted to the excitation thyristor converter 7, and system stabilization operation can be performed. The control device 13 is installed to control the circuit components described above and operate the entire system normally. [00211 Although not particularly shown in each embodiment, by forming the PC 81 with a non-inductively wound superconducting coil, the inductance can be reduced to almost 0, and the inductance from the external power source can be reduced to almost zero. Almost no current is applied to the superconducting coil, but effectively flows into the PC 81. [0022] Therefore, in addition to being able to reduce the capacity of the external power source, it is also possible to achieve operational reliability and high speed. If the PC 82 is also formed of a superconducting coil with non-inductive winding, the same effect can be obtained. [0023]

[Effects of the Invention] According to the superconducting device, superconducting energy storage device, and operating method thereof of the present invention described above, persistent current switches can be opened extremely quickly, and system disturbances can be instantaneously responded to. Of course, there is almost no loss of stored energy, and extremely high efficiency can be obtained, which has great effects.

[Brief explanation of the drawing]

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

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a third embodiment of the present invention.

[Explanation of symbols]

1... Current type persistent current switch, 2... Thermal type persistent current switch, 3... Superconducting coil, 4... Cryostat, 5... Capacitor, 6... Cyrisk switch, 7... Excitation thyristor converter, 8... Power system, 10... Discharge current, 11... Switching means, 12
...Voltage detector, 13...Control device.

[Figure 1]

[Figure 2]

[Figure 3]

Claims (23)

[Claims] 1. A superconducting device characterized in that a current-type persistent current switch is provided in parallel with a superconducting coil, and the switch operates to open the circuit when energized at a critical current value or higher. 2. A superconducting coil; a persistent current switch connected in parallel with the superconducting coil and closed to cause a persistent current to flow when a set energy is stored in the superconducting coil; A superconducting device comprising a cryostat that accommodates a coil, characterized in that a power supply device is provided outside the cryostat to apply a current equal to or higher than a critical current value to the persistent current switch to open the circuit. 3. The persistent current switch according to claim 1, wherein the persistent current switch is formed of a non-inductively wound superconducting coil.
Or the superconducting device according to 2. 4. A superconducting coil, an excitation power source that excites the superconducting coil, and a circuit that is closed in order to cause a persistent current to flow through the superconducting coil when a set energy is stored in the superconducting coil by the excitation power source. A superconducting energy storage device comprising a persistent current switch, wherein the persistent current switch has at least a function of opening a circuit when energized at a critical current value or higher. 5. A superconducting coil, an excitation power source that excites the superconducting coil, and a circuit that is closed in order to cause a persistent current to flow through the superconducting coil when a set energy is stored in the superconducting coil by the excitation power source. Persistent current switch;
A superconducting energy storage device comprising the persistent current switch and a cryostat housing the superconducting coil, characterized in that a power supply device is provided outside the cryostat to cause the persistent current switch to perform an opening operation when energized at a critical current value or higher. A superconducting energy storage device. 6. A superconducting coil, an excitation power supply that excites the superconducting coil, and a circuit that is closed in order to cause a persistent current to flow through the superconducting coil when a set energy is stored in the superconducting coil by the excitation power supply. In a superconducting energy storage device equipped with a thermal type or magnetic field type persistent current switch, a current type persistent current switch that operates to open circuit when energized at a critical current value or more is connected in series with the thermal type or magnetic field type persistent current switch. A superconducting energy storage device characterized by: 7. A superconducting coil, an excitation power supply connected to a power system and exciting the superconducting coil, and applying a permanent current to the superconducting coil when a set energy is stored in the superconducting coil by the excitation power supply. In a superconducting energy storage device equipped with a persistent current switch that is closed to allow current to flow, the persistent current switch operates to open when energized at a critical current value or higher when an operation command for stabilizing the power system is issued. A superconducting energy storage device characterized by having at least the following functions: 8. A superconducting coil, an excitation power supply that excites the superconducting coil, and a circuit that is closed in order to cause a persistent current to flow through the superconducting coil when a set energy is stored in the superconducting coil by the excitation power supply. In a superconducting energy storage device equipped with a thermal type or magnetic field type persistent current switch, a current type persistent current switch whose opening operation is controlled by an external current is connected in series with the thermal type or magnetic field type persistent current switch. A superconducting energy storage device, further comprising: a power supply device for supplying current to the current type persistent current switch from the outside in parallel with the superconducting coil. 9. A superconducting coil, an excitation power supply that excites the superconducting coil, and a circuit that is closed in order to cause a persistent current to flow through the superconducting coil when a set energy is stored in the superconducting coil by the excitation power supply. In a superconducting energy storage device equipped with a thermal type or magnetic field type persistent current switch, a current type persistent current switch that operates to open circuit when energized at a critical current value or more is connected in series with the thermal type or magnetic field type persistent current switch. A superconducting energy storage device characterized in that a power supply device for energizing the current-type persistent current switch is provided in parallel with the superconducting coil. 10. A superconducting coil, an excitation power supply for exciting the superconducting coil, and a circuit closed to cause a persistent current to flow through the superconducting coil when a set energy is stored in the superconducting coil by the excitation power supply. In a superconducting energy storage device equipped with a persistent current switch, the persistent current switch has a property of being thermally or magnetically controlled to open and close, and is opened when energized at a critical current value or more, and closed with a transient thermal time constant. A superconducting energy storage device characterized by having the following characteristics. 11. A superconducting coil, an excitation power supply for exciting the superconducting coil, and an open circuit when the excitation power supply excites the superconducting coil and storing energy, and when the set energy is stored. In a superconducting energy storage device comprising a thermal type or magnetic field type persistent current switch that is closed and causes a persistent current to flow through the superconducting coil, the superconducting coil is operated at high speed in series with the thermal type or magnetic field type persistent current switch. A superconducting energy storage device characterized in that a current-type persistent current switch is connected that opens the circuit only when it is desired to connect to the excitation power source. 12. Claim 4, wherein the persistent current switch, which opens when energization exceeds the critical current value, is formed of a non-inductively wound superconducting coil. 5. 7 or 10
The superconducting energy storage device described. 13. The current type persistent current switch is formed of a non-inductively wound superconducting coil.
, 8. 9. The superconducting energy storage device according to 11. 14. Energy is stored in the superconducting coil by exciting it with an excitation power source connected to a power system while a persistent current switch connected in parallel with the superconducting coil is open, and the stored energy is a set value. In the method of operating a superconducting energy storage device, the persistent current switch is closed at the time when the permanent current switch is closed, the excitation power supply is stopped, and the persistent current continues to flow through the superconducting coil, wherein a persistent current is flowing through the superconducting coil. If there is an operation command from the power system to stabilize the system in the current state, a current exceeding the critical current value is applied to the persistent current switch to open the circuit, and only for the time until the circuit is reclosed. A method for operating a superconducting energy storage device, characterized in that energy stored in the superconducting coil is taken out to a system side of the excitation power source. 15. Energy is stored in the superconducting coil by exciting it with an excitation power supply connected to a power system while a persistent current switch connected in parallel with the superconducting coil is open, and the stored energy is a set value. In the method of operating a superconducting energy storage device, the persistent current switch is closed at the point where the persistent current switch is closed, the excitation power supply is stopped, and the persistent current continues to flow through the superconducting coil. A current is applied to open the circuit, and the circuit is automatically reclosed after a few seconds due to the transient thermal time constant of the opened persistent current switch, and the excitation power source is operated for a period necessary for system stabilization operation of the superconducting coil. A method of operating a superconducting energy storage device, the method comprising: electrically connecting a superconducting energy storage device to a superconducting energy storage device; 16. Storing energy in the superconducting coil by exciting it with an excitation power supply connected to the power system with a thermal type or magnetic field type persistent current switch connected in parallel with the superconducting coil in an open state, A method for operating a superconducting energy storage device that closes the thermal or magnetic persistent current switch when the stored energy reaches a set value, stops the excitation power source, and continues to flow persistent current through the superconducting coil. In this step, a current type persistent current switch is connected in series with the thermal type or magnetic field type persistent current switch, and an operation command for system stabilization is received from the power system while a persistent current is flowing through the superconducting coil. In this case, a current exceeding the critical current value is applied to the current-type persistent current switch to open the circuit, and the stored energy of the superconducting coil is transferred to the system side of the excitation power supply only for a period until the circuit is reclosed. 1. A method of operating a superconducting energy storage device, characterized in that the superconducting energy storage device is adapted to take out. 17. Storing energy in the superconducting coil by exciting it with an excitation power supply connected to the power system with a thermal or magnetic field persistent current switch connected in parallel with the superconducting coil in an open state, A method for operating a superconducting energy storage device that closes the thermal or magnetic persistent current switch when the stored energy reaches a set value, stops the excitation power source, and continues to flow persistent current through the superconducting coil. , a current type persistent current switch that opens when a current equal to or higher than a critical current value is applied is connected in series to the thermal type or magnetic field type persistent current switch, and
The opened current type persistent current switch is automatically reclosed after several seconds due to its transient thermal time constant, and the superconducting coil is electrically connected to the excitation power source for a period necessary for system stabilization operation. A method of operating a superconducting energy storage device characterized by: 18. A superconducting coil connected to a power system,
Superconducting energy comprising: an excitation power source that excites the superconducting coil; and a persistent current switch that is closed to cause a persistent current to flow through the superconducting coil when a set energy is stored in the superconducting coil by the excitation power source. In the storage device, the persistent current switch has at least a function of opening the circuit by energization of a critical current value or more when an operation command for stabilizing the power system is issued, and a power supply that energizes the persistent current switch. The device is installed in parallel with the superconducting coil, and when the excitation power source excites the superconducting coil, and when an operation command is issued for power system stabilization, the external power supply voltage to the persistent current switch falls below a predetermined value. A superconducting energy storage device characterized in that a switching means is provided in series with the excitation power source, which operates to close the circuit when the current value of the superconducting coil reaches a set current, and to open the circuit when the current value of the superconducting coil reaches a set current. 19. A superconducting coil connected to a power system,
an excitation power source that excites the superconducting coil; and a thermal or magnetic field type persistent current switch that is closed to cause a persistent current to flow through the superconducting coil when a set energy is stored in the superconducting coil by the excitation power source. A superconducting energy storage device comprising: a current type persistent current switch whose opening operation is controlled by an external current is connected in series with the thermal type or magnetic field type persistent current switch; A power supply device is provided in parallel with the superconducting coil for supplying a current from the outside to the superconducting coil, and when the excitation power source excites the superconducting coil and an operation command is issued for power system stabilization, the current-type persistent current is A switching means is provided in series with the excitation power source, which operates to close the circuit when the voltage of the external power supply to the switch falls below a predetermined value, and to open the circuit when the current value of the superconducting coil reaches the set current. A superconducting energy storage device characterized by: 20. The superconducting energy storage device according to claim 18, wherein the opening/closing means is an input device. 21. The superconducting coil according to claim 18 or 19, further comprising a voltage detector provided in parallel with the superconducting coil for confirming that an external power supply voltage to the persistent current switch has fallen below a predetermined value. superconducting energy storage device. 22. Energy is stored in the superconducting coil by exciting it with an excitation power source connected to the power system while a persistent current switch connected in parallel with the superconducting coil is open, and the stored energy is a set value. In the method of operating a superconducting energy storage device, the persistent current switch is closed at the time when the permanent current switch is closed, the excitation power supply is stopped, and the persistent current continues to flow through the superconducting coil, wherein a persistent current is flowing through the superconducting coil. When an operation command is received from the electric power system for system stabilization in the state, a current exceeding a critical current value is applied to the persistent current switch to open the circuit, and the external power supply voltage is lowered to a predetermined value or less. When this occurs, the switching means provided in series with the excitation power source is closed to shift the superconducting coil current to the excitation power source,
A method for operating a superconducting energy storage device, characterized in that the energy stored in the superconducting coil is taken out to the system of the excitation power source only during a period until the persistent current switch is reclosed. 23. Storing energy in the superconducting coil by exciting it with an excitation power supply connected to the power system with a thermal type or magnetic field type persistent current switch connected in parallel with the superconducting coil in an open state, A method for operating a superconducting energy storage device that closes the thermal or magnetic persistent current switch when the stored energy reaches a set value, stops the excitation power source, and continues to flow persistent current through the superconducting coil. In this step, a current type persistent current switch is connected in series with the thermal type or magnetic field type persistent current switch, and an operation command for system stabilization is received from the power system while a persistent current is flowing through the superconducting coil. In this case, the current-type persistent current switch is energized with a current equal to or higher than the critical current value to open the circuit, and when the external power supply voltage falls below a predetermined value, the opening/closing means provided in series with the excitation power supply is activated. The superconducting coil current is shifted to the excitation power source by closing the circuit, and the stored energy of the superconducting coil is taken out to the system side of the excitation power source only for a period until the current type persistent current switch is reclosed. A method of operating a superconducting energy storage device characterized by: