JPS633132Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a static tap switching device that switches taps using a thyristor switch.

The static type tap switching device uses a thyristor switch instead of the mechanical tap switching device of the conventionally widely used automatic voltage regulator, making it non-contact, and there is no limit to the number of times the tap can be changed. It has the characteristics that the operating time can be shortened and the voltage can be finely adjusted. By the way, in conventional static type tap switching devices, each tap is connected to a A current limiting reactor is inserted in each. However, if a current limiting reactor is inserted into each tap, it is necessary to provide the same number of current limiting reactors as the number of taps, which has the disadvantage of increasing the size and weight of the device.

The purpose of the present invention is to provide a static type tap that, regardless of the number of taps, can obtain the same effect as when each tap is provided with its own current limiting means by simply providing two current limiting means. An object of the present invention is to provide a switching device.

In the present invention, only the first and second current limiting means are provided as the current limiting means, and the first and second thyristors constituting the thyristor switch are respectively connected to a plurality of taps of the voltage regulating transformer. The anode side terminals of the first thyristors whose cathode side terminals are connected to the taps are commonly connected and connected to one end of the first current limiting means. Further, the cathodes of the second thyristors whose anode side terminals are connected to the taps are commonly connected to one end of the second current limiting means, and the other ends of the first and second current limiting means are commonly connected. Connect to the terminal connected to the power supply line. With this configuration, regardless of the number of taps, it is possible to protect the thyristors connected to each tap by simply providing two current limiting means per tap, thereby simplifying the structure of the tap switching device. It can be done. The present invention is particularly advantageous when the number of taps is large, and by applying the present invention, it becomes possible to provide a small and inexpensive tap switching device that has a large number of taps and performs fine voltage adjustment.

Note that the first and second thyristors constituting the thyristor switch connected to each tap are not necessarily limited to a single thyristor element, but may include multiple thyristor elements to increase current capacity. A plurality of thyristor elements can be connected in parallel and used, or a plurality of thyristor elements can be connected in series to increase the withstand voltage capacity. Therefore, in this specification, the term "thyristor" is used to include a combination of a plurality of thyristor elements in parallel or series.

Next, embodiments of the present invention will be described with reference to the drawings.

The drawing shows the main part of an embodiment in which the present invention is applied to a single-phase static tap switching device. In the drawing, T is an autotransformer for voltage regulation having taps t ₁ to _{t 5} . , thyristor switches _S1 to _S5 are connected to the taps _t1 to _t5 , respectively. Thyristor switches S ₁ to _{S 5} are each the first thyristor
Consisting of Th ₁ a to Th ₅ a and second thyristors Th ₁ b to Th ₅ b, the first thyristors Th 1 a to _{Th 5} a of the thyristor switches S ₁ to S ₅ have their respective cathodes tapped t ₁ ~t connected to ₅ . Further, the anodes of the first thyristors Th ₁ a to _{Th 5} a of the thyristor switches S ₁ to S ₅ are commonly connected, and the common connection point of the anodes of these first thyristors serves as a first current limiting means. Connected to one end of reactor _L1 . On the other hand, the anodes of the second thyristors Th ₁ b to Th ₅ b of the thyristor switches S ₁ to S ₅ are connected to the taps t ₁ to _{t 5} , respectively, and the cathodes of these second thyristors are commonly connected and is connected to one end of a current limiting reactor _L2 as a current limiting means. The other ends of the current limiting reactors L ₁ and L ₂ are commonly connected, and the common connection point of both reactors is connected to a power supply side line terminal U connected to one line on the power supply side. Also, one end of the winding in the voltage regulating transformer T on the transparent tap _t1 side is connected to the load side line terminal u connected to one of the lines on the load side, and the other end of the winding in the transformer T is It is connected to a power supply side line terminal V and a load side line terminal v which are respectively connected to the other line on the power supply side and the other line on the load side.

Although not shown, the thyristor switch S ₁ to
A control circuit is provided to control _S5 , and taps can be switched without interruption while temporarily short-circuiting predetermined taps through current limiting reactor _L1 or _L2 . For example, the first and second thyristors Th ₁ a and Th ₁ b of the thyristor switch S ₁
When a step-up command to switch to tap _t2 is issued in a state where tap t1 is energized with alternate conduction and clear conduction, first thyristors Th ₂ a and _{Th 2 b} of thyristor switch S ₂ are turned on. A continuous firing signal is provided and then the supply of the firing signal to the thyristor switch S ₁ is stopped to effect a changeover of the tap from t ₁ to t ₂ . For example, if a step-up command to switch from tap t ₁ to t ₂ is issued during a half cycle in which the first thyristor _{Th 1} a of the thyristor switch S ₁ is conducting, the first and second thyristors Th 2 of the thyristor switch S ₂ A continuous firing signal is applied to a and Th ₂ b, which causes thyristor Th ₁ a as well as thyristor Th ₂ a to conduct and continue to energize the load. At this time, thyristor Th ₂ b to which the voltage between taps t 1 and t ₂ is applied in the forward direction also becomes conductive, so that between thyristor _{Th 1 a} - taps t ₁ and t ₂ - thyristor Th ₂ b - current limiting reactor L ₂ and L ₁ - thyristor Th ₁ A short-circuit current flows between the taps in the loop, but
Since this current is limited by the current limiting reactors _L2 and _L1 , the thyristor will not be damaged by excessive current flowing through it. Subsequently, when the supply of the ignition signal to the thyristor switch S ₁ is stopped, the first thyristor Th ₁ a is cut off when the potential of its anode becomes zero or negative with respect to the cathode. From now on, each thyristor Th ₂ a of thyristor switch S ₂ ,
Th ₂ b alternately conducts, and current is applied at tap t ₂ . Also, tap _t1 to turn on the second thyristor.
If a boost command is given while Th ₁ b is conducting, thyristor Th ₁ b - current limiting reactor
Switching to tap _t2 is performed uninterrupted while creating a short circuit between the taps in the loop between _L2 and L1 - thyristor _Th2a - taps _{t2, t1 - thyristor Th1b} .

In the above embodiment, when stud-type thyristors are used as each thyristor, the thyristors Th ₁ a to Th ₅ a have studs on the anode side, and each anode is attached to one heat sink, By using thyristors Th ₁ b to _{Th 5} b whose cathode side is studded and attaching each cathode to one heat sink, the thyristor can be mounted using only two heat sinks. The structure can be simplified.

In the above embodiment, the case where it is applied to a single-phase circuit is taken as an example, but by using two voltage regulating transformers shown in the figure to make a V connection, or by using three voltage regulating transformers to make a three-phase connection, a three-phase circuit can be applied. Of course, it can be applied to.

Although current limiting reactors are used as the first and second current limiting means in the above embodiments, current limiting resistors may be used in place of the current limiting reactors.

In the above embodiment, the voltage regulating transformer is an autotransformer, but the present invention can be similarly applied to the case where this is an insulating transformer and a tap is provided on the primary or secondary side for switching.

As described above, according to the present invention, even if the number of taps increases, the number of current limiting means does not change, and the purpose can always be achieved with a small number of two current limiting means, reducing the size and weight of the tap switching device and reducing costs. It has the advantage of being able to achieve this.

[Brief explanation of the drawing]

The drawing is a connection diagram showing the main parts of an embodiment of the present invention. T...Voltage adjustment transformer, _S1 to _S5 ...Thyristor switch, _Th1a to _Th5a ...First thyristor, _Th1b to _Th5b ...Second thyristor, _L1 ... …
Current-limiting reactor (first current-limiting means), L ₂ ... current-limiting reactor (second current-limiting means).

Claims (1)

[Claims for Utility Model Registration] (1) Connecting the cathode terminal of a first thyristor and the anode terminal of a second thyristor to each of a plurality of taps provided on a voltage regulating transformer, connecting the anodes of the first thyristors respectively connected to the plurality of taps to one end of the first current limiting means;
The cathodes of the second thyristors respectively connected to the plurality of taps are commonly connected to one end of the second current limiting means, and the other ends of the first and second current limiting means are commonly connected. A static tap switching device characterized in that it is connected to a terminal connected to a power supply line. (2) The stationary tap switching device according to claim 1, wherein the first and second thyristors each consist of a single thyristor element. (3) The static tap switching device according to claim 1, wherein each of the first and second thyristors is constructed by connecting a plurality of thyristor elements in parallel. (4) The stationary tap switching device according to claim 1, wherein each of the first and second thyristors is constructed by connecting a plurality of thyristor elements in series.