JP2789095B2 - Uninterruptible power system switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to uninterruptible system switching for continuing uninterrupted power supply when power supply from a main line of a power system to a demand load is stopped due to an accident or the like. It concerns the device. [Prior art] Generally, an electric power system is a system that collects electricity from generation to consumption, that is, generates electricity at a power plant, transmits it by a transmission line, and further uses a distribution line to various factories and homes. This is a system that collectively distributes power and reaches the load equipment. Since the power transported by the transmission line remains at the transmission voltage and cannot be supplied to consumers immediately, the voltage must be reduced several times to a voltage suitable for the demand load. In a grid-connected power system, if an accident occurs anywhere on the track, the consequences can quickly spread to all areas. Therefore, even if an accident occurs, it is extremely important from the viewpoint of maintenance and security and to constantly supply power to prevent the influence of the accident from being locally transmitted to other parts. In the midst of transforming into an advanced information society,
In particular, various computer systems are required to further improve reliability, and in order to operate the system without interruption, even if the power supply from the main line of the power system stops due to an accident or the like, power supply will continue without interruption To do so, an uninterruptible power supply (CVCF device), a motor generator, and the like are used as well-known devices. CVCF equipment has undergone a dramatic technological change, especially with the development of online computer systems. This is to continue supplying power without interruption using the current of the storage battery in the event of an accident, and is composed of semiconductor elements such as transistors, thyristors, and diodes in addition to the storage battery.
On the other hand, a motor generator generally includes a motor, a flywheel, a generator, and the like. When the power supply from the main line is stopped, the generator automatically operates to continue power supply. [Problems to be solved by the invention] However, the CVCF apparatus requires a high-precision element,
In addition, the circuit incorporating the element is complicated, and in the case of the motor generator, the generator and related equipment are large and have a complicated structure. The apparatus for supplying power without interruption is generally complicated in structure, has a low reliability, and is large and expensive. Also, if the demand load increases with the development of the industry, the power system will gradually increase in scale and complexity due to the development of power sources and the reinforcement of facilities. In order for electric utilities to be able to supply good quality with abundant and inexpensive electricity, this entire power system must always be operated reasonably and economically, minimizing the total cost of electricity supplied to the load. It is important. Therefore, in view of the above, it is an object of the present invention that the power supply can be continued without interruption even if the power supply from the main line of the power system to the demand load is stopped due to an accident or the like. Another object of the present invention is to provide a small and inexpensive uninterruptible power system switching device that is simple, highly reliable, and inexpensive. [Means for Solving the Problems] The purpose of the present invention is to provide a switch to continue full power supply to the demand load without interruption from the backup line in place of the main line when power supply from the main line of the power system to the demand load is stopped. A device,
A shut-off mechanism that is connected to the main line and is in a closed operation state when power is supplied from the main line to a demand load, and opens when the power supply stops, a branch line branching off from the main line downstream of the shut-off mechanism, a spare line Forming a part of the superconducting wire having a current-limiting action, and holding the non-superconducting wire with the superconducting wire by supplying power from the branch line while the shutoff mechanism is in the closed operation state, and the shutoff mechanism is opened. Transition means for shifting the superconducting wire from the non-superconductor to the superconductor when power supply from the branch line is stopped. The switching device of the present invention uses a superconducting wire having a current-limiting action.Normally, a shut-off mechanism provided on the main line is in a closed state, and power is supplied from the main line to a demand load. If the power supply from the main line stops due to an accident such as a ground fault and the current stops flowing to the main line, the cut-off mechanism opens and the switch automatically switches to the spare line to which the superconducting wire is connected. Power supply can be continued without interruption. However, the superconducting wire of the backup line is a non-superconductor when power is supplied from the main line, and prevents power supply from the backup line. The body shifts in a short time and supplies power in the event of a power failure instead of the main line. When the main line is restored and the current flows through the main line, the superconducting wire shifts from the superconductor to the non-supermotor in a short time at the same time as the closing operation of the shutoff mechanism, and returns to the normal power supply state. That is, the switching device of the present invention exclusively utilizes the characteristics of both the superconductor and the non-superconductor of the superconducting wire connected to the backup line. The transition means in the present invention makes use of both the characteristics of the superconductor and the non-superconductor of the superconducting wire, and while the shutoff mechanism is in the closed operation state, a branch line branched from the main line on the downstream side of the shutoff mechanism. A function to transfer the superconducting wire from the non-superconductor to the superconductor when the cutoff mechanism opens and the power supply from the branch line is stopped when the power supply from the Eggplant There is no particular limitation on the mechanism as long as the transfer means performs such a function. For example, magnetic field applying means for applying a magnetic field equal to or more than the critical magnetic field of the superconducting wire to the superconducting wire are listed. This is because when the power is supplied from the main line, the shut-off mechanism is in the closed operation state, and the power supply from the branch line applies a magnetic field more than the critical magnetic field to the superconducting wire to make the superconducting wire a non-superconductor and cut off. The superconducting wire is turned into a superconductor by applying a magnetic field below the critical magnetic field simultaneously with the opening operation of the mechanism, and when switching to mains power, a magnetic field above the critical magnetic field is applied again. This is a means for positively exhibiting the current-limiting action by transferring to the body and the superconducting action by transferring from the non-superconductor to the superconductor. As a material of the superconducting wire, there is a metal-based or ceramic-based superconducting material. The metal-based superconducting materials include niobium, titanium, zirconium, vanadium, and tantalum, and the ceramic-based superconducting material or a mixture of the raw materials is not particularly limited, but is a ceramic material containing an oxide of a rare earth element. Is preferred.
As such a material, an existing material may be provided. For example, barium, yttrium, copper,
Oxygen, barium / lanthanum / copper / oxygen, strontium / lanthanum / copper / oxygen, barium / scandium / copper /
There is a ceramic having a composition of oxygen or calcium, lanthanum, copper, and oxygen, and preferably a material having a composition of barium, yttrium, copper, and oxygen, which is an yttrium-based ceramic material that is becoming mainstream. Further, when this yttrium-based superconducting material is used, its preferable compounding ratio is Ba: Y: Cu: O = 2: 1: 3: 6 to 7. The superconducting wire may be produced by a conventional method using the above-mentioned metallic or ceramic superconducting material. Also, superconducting wires make use of the characteristics of both superconductors and non-superconductors, but ceramic materials are originally excellent electrical resistors, that is, non-superconductors. To prevent power supply from the spare line, a superconducting wire made of a ceramic-based superconducting material is preferable. [Embodiment] Hereinafter, an uninterruptible power system switching device of the present invention will be described based on an embodiment. FIG. 1 shows a schematic circuit of one embodiment. The switching device SW shown in the figure is a case of three-phase AC in a power system, but a case of single-phase AC is substantially similar to this. Electric power from the main line 10 of three-phase alternating current is supplied to the demand load 20, and a dummy load 21 is installed on the main line 10 in case of no load. In parallel with the main line 10, there is provided a spare line 30 connected to another power supply system for continuing power supply in place of the main line 10 when power supply from the main line 10 is stopped. Main line 10
When the power supply from the main line 10 to the load 20 is stopped due to an accident or the like and the current stops flowing to the main line 10, the main line 10 is disconnected, and the power supply from the main line 10 is resumed, and the current is An interrupting mechanism for connecting the main line 10 at the same time as flowing to the main line 10 is attached. As is clear from the figure, this interrupting mechanism is associated with the shunt resistor r connected to the main line 10, the coil 41 connected in series with the shunt resistor r, and the excitation / demagnetization inserted in the coil 41. Displaced iron bar 42, iron bar 42
And a switch 44 that opens and closes the main line 10 in accordance with the displacement of the iron bar 42. In addition, the three shut-off mechanisms attached to the three-phase alternating current main line 10 are linked even if the current of any main line stops flowing, that is, if one of the three phases is interrupted by an accident, the other normal phases are also shut off. A mechanism 45 (not particularly shown) is provided. A branch line 50 is connected to the downstream side of the shut-off mechanism of the main line 10, and a part of the alternating current of the main line 10 branches off at the branch line 50, and is converted into DC by a rectifier 51 provided on the branch line 50. It flows on a branch line 50 'derived from 51. As shown in FIG. 2, the branch line 50 'is wound around an annular core 52, and a gap 53 is formed in the annular core 52 at regular intervals. A superconducting wire G having a current limiting function connected to the backup line 30 is arranged in the gap 53. If a direct current flows through the branch line 50 ', a magnetic field generated in the gap 53 is applied to the superconducting wire G. I have. The superconducting wire G varies depending on the critical temperature of the superconducting material. To maintain the superconducting state, the superconducting wire G is housed together with the annular core 52 in a cooling tank 55 containing a coolant, for example, and is constantly cooled. An example of the superconducting wire G connected to the backup line 30 is shown in FIGS. The superconducting wire G shown here is made of a ceramic-based superconducting material, and a thin metal layer 72 obtained by drawing is formed around a superconductor (or non-superconductor) 71 made of a ceramic material. In this state, the superconducting wire G is difficult to handle even if it is connected to the spare line 30. Therefore, terminals 73 are attached to both ends at the joints 74. The terminal 73 is made of the same material as the thin metal layer 72 (that is, copper, silver,
The terminal 73 may be made of ohmic connection, bolt connection, compression connection, or the like, or may be integrally formed with the superconducting wire G, made of aluminum, nickel, etc.) or another good conductive material (eg, brass, etc.). Other modes may be used. The switching device SW having such a structure does not require a complicated circuit or a large device such as a generator, and has a simple structure, is downsized, is easy to maintain and inspect, and has high reliability. It is cheap. Next, the operation of the switching device SW will be described. Main line 10
When power is being supplied from the mains 10, the current flows through the mains 10 and the shunt resistor r in the shut-off mechanism
When the current shunted from flows through the coil 41, the coil 41 is excited, the iron bar 42 overcomes the urging force of the coil spring 43 and is displaced in the direction of arrow B, and the switch 44 is closed. When the cutoff mechanism is in the closed state, current flows through the branch line 50, and the current converted to DC by the rectifier 51
By flowing through the branch wire 50 ′ wound around 52, a magnetic field greater than the critical magnetic field of the superconducting wire G is generated in the gap 53 of the annular core 52, and the magnetic field is applied to the superconducting wire G disposed in the gap 53. As a result, the superconducting phase of the superconducting wire G is broken, and the superconducting wire G is an electrical resistor, which is an original characteristic of the ceramic material, and blocks power supply from the spare line 30. Here, if an accident such as a short circuit or ground fault occurs for some reason and even one of the three phases stops power supply and current no longer flows through the main line 10 of the phase, the interlocking mechanism 45 operates the normal other phase. At the same time, current does not flow through the shunt resistor r, the coil 41 is demagnetized, the iron bar 42 is displaced in the direction of arrow A by the restoring force of the coil spring 43, and the switch 44 is opened to connect the three-phase Disconnect. At the same time as the opening operation of the shutoff mechanism, the current stops flowing through the branch lines 50 and 50 ′, and the magnetic field generated in the gap 53 of the annular core 52 disappears. As a result, the superconducting wire G shifts from the non-superconductor to the superconductor in a short time, and is immediately switched from the main line 10 to the spare line 30 to continue power supply. After that, when the accident of the main line 10 is recovered, the interruption mechanism is closed and at the same time, the current flowing through the branch lines 50 and 50 'generates a magnetic field in the gap 53 of the annular core 52, and the superconducting wire G is moved from the superconductor to the non-superconducting wire. The body moves in a short time and returns to the normal power supply state. The present invention is not limited to the above embodiment. For example, the magnetic field applying means may be operated not in accordance with the presence / absence of current in the main line but in conjunction with the opening / closing operation of the shut-off mechanism. . [Effects of the Invention] As described above, the uninterruptible power system switching device of the present invention is provided with a breaking mechanism on the main line of the power system, and the superconducting wire connected to the backup line is connected to the non-superconductor in accordance with the opening / closing operation of the breaking mechanism. The superconductor or the means for shifting from the superconductor to the non-superconductor in a short time is provided, and the characteristics of both the superconductor and the non-superconductor of the superconducting wire are effectively used. When the power supply stops due to an accident or the like, the superconducting wire is shifted from the non-superconductor to the superconductor by the transition means and switched to the power supply from the spare line, and if the power supply from the main line is resumed, the superconducting wire is replaced by the superconductor. To a non-superconductor to stop the power supply from the spare line and return to the normal power supply state, to continue the power supply to the demand load without interruption, and to use a general motor generator or CVCF
The structure is extremely simple and small compared to devices, etc.
This is a breakthrough that allows the power system to operate rationally and economically.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic circuit diagram showing an example of attaching an uninterruptible power system switching device of the present invention to a main line of a power system and showing a case of three-phase AC, and FIG. 2 is a switching diagram of FIG. FIG. 3 is a schematic front view of a magnetic field applying means of the device, FIG. 3 is a plan view of one embodiment of a superconducting wire used in the switching device of the present invention, and FIG. 4 is a side sectional view of the superconducting wire shown in FIG. . SW: switching device, 43: coil spring G: superconducting wire, 44: switch r: resistor, 50, 50 ': branch line 10: main line, 52: annular core 20: demand load, 53: gap 30, spare line, 55: Cooling tank 41: Coil 42: Iron bar

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02J 9/00 H01F 6/00 H01L 39/18

Claims (1)

(57) [Claims] A switching device for continuing power supply to the demand load without interruption from the main line in place of the main line when power supply from the main line of the power system to the demand load is stopped. When the power is supplied to the power supply, the power supply is in the closed state, and when the power supply is stopped, the cutoff mechanism is opened, a branch line branching off from the main line downstream of the cutoff mechanism, and a part of the spare line are formed. While the superconducting wire having the flow action and the shut-off mechanism were in the closed operation state, the superconducting wire was held on the non-superconductor by power supply from the branch line, and the cut-off mechanism opened and the power supply from the branch line stopped. An uninterruptible power system switching device, which sometimes includes a transition means for transitioning the superconducting wire from the non-superconductor to the superconductor. 2. The transition means is a magnetic field applying means for applying a magnetic field equal to or less than the critical magnetic field of the superconducting wire to the superconducting wire at the same time as the opening operation of the interrupting mechanism, and applying a magnetic field greater than the critical magnetic field to the superconducting wire at the same time as the closing operation of the interrupting mechanism. The uninterruptible power system switching device according to claim 1, characterized in that: 3. The magnetic field applying means includes the branch line and an annular core wound around the branch line via a rectifying device, a gap is formed in the annular core, and a spare superconducting wire is arranged in the gap. The uninterruptible power system switching device according to item (2). 4. The uninterruptible power system switching device according to any one of claims (1) to (3), wherein the superconducting wire is made of a ceramic-based superconducting material. 5. The components of the ceramic superconducting material that constitutes the superconducting wire are barium, yttrium, copper, oxygen, barium, lanthanum, copper, oxygen, strontium, lanthanum, copper, oxygen, barium, scandium, copper, oxygen, or calcium, lanthanum, copper. -The uninterruptible power system switching device according to claim (4), wherein the device is oxygen.