JPS622748Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to reducing the capacity of load breakers and tap changers in transformers where large current loads must be frequently switched on and off.

Generally, in transformers such as transformers for electric furnaces, which have a large output current and must frequently switch on and off the load, a sheath breaker is placed on the secondary side, but due to the large current, the sheath disconnects frequently. It becomes a very expensive device. If you try to avoid this, the primary side will be disconnected, but if the primary side is at high voltage,
The high voltage results in a large number of disconnections, and it is also very expensive and complicated.

Therefore, it was necessary to provide another step-down transformer on the primary side of this transformer to lower the primary voltage of the transformer to a low voltage suitable for the shunt. In order to avoid this inconvenience, there is a load circuit disconnection tap switching transformer shown in FIG. 1 which is a so-called tertiary circuit circuit disconnection system. This device includes a main transformer 101 having a primary winding 1, a secondary output winding 2, a tap winding 3, and a base winding 4, and a secondary output winding 2 of the main transformer 101. A series transformer 102 is provided in which the windings 5 are connected in series, and the primary winding 6 of the series transformer 102 is connected in series with the tap winding 3 and base winding 4 of the main transformer 101, so that the windings 5 can be A coil 7 is connected between the tap winding 3 and the base winding 4, for example.

In this device, the chopper, disconnector 7, and on-load tap changer (not shown) are inserted into the tertiary winding circuit formed by the tap winding 3 and base winding 4 of the main transformer 101, so they are relatively The voltage is low and the current is small, so the circuit breaker and tap changer require relatively small capacity. However, if a larger capacity transformer is required, the voltage of the tap changer circuit must be lowered, taking into account the voltage characteristics of the circuit breaker, and the current increases significantly. We were forced to adopt a current tap changer.

The present invention was devised in view of this point, and its purpose is to reduce the capacity of the breaker and on-load tap changer. According to the present invention, to achieve this purpose,
A main transformer having a primary winding, a secondary output winding, and a tertiary winding, a series transformer in which the secondary winding is connected in series with the secondary output winding of this main transformer, and a primary winding of this series transformer. An autotransformer in which the secondary winding is connected to the line through a tap winding, and the tertiary winding of the main transformer and the primary winding of the autotransformer are connected to the primary winding of this autotransformer. This constitutes a load/disconnect tap switching transformer comprising a load/disconnector connected between the line and the line.

Next, embodiments of the present invention will be explained in detail with reference to the drawings.

In Figure 2, primary winding 1 and secondary output winding 2
A secondary winding 5 of a series transformer 102 is connected in series to a secondary output winding 2 of a main transformer 201 having a tertiary winding 21 and a tertiary winding 21 . A secondary winding 22 of an autotransformer 103 is connected to the primary winding 6 of the series transformer 102 via a tap winding 23.

The primary winding 24 of the autotransformer 103 is connected to the main transformer 2
This tertiary winding 2 is connected to the tertiary winding 21 of 01.
A load and disconnector 7 is connected between the primary winding 24 and the primary winding 24 . The tertiary winding 21 can also be used as a power factor correction capacitor winding.

According to the transformer of the present invention, the breaker circuit and the tap changer circuit are connected to the autotransformer 103.
As a result, the optimum voltage and current can be selected for each of the shield breaker and tap changer, and a reduction in capacity can be achieved. That is, since the primary voltage and current of the series transformer 102 can be selected independently of the primary voltage or secondary current of the main transformer 101, it is possible to frequently load the load at small current and low voltage by using an appropriate small capacity load or disconnector 7. Can be opened and closed.

Furthermore, even if the main transformer 101 is connected to a large power source and the short-circuit capacity on the primary side is very large, the short-circuit capacity required for the disconnector 7 can be arbitrarily small, so it is not particularly loaded. Also, the capacity of the disconnector 7 is reduced significantly.

As explained above, according to the present invention, the capacity of the load/disconnector and tap changer can be reduced, and a large capacity load/disconnector/tap switching transformer can be provided at a relatively low cost. There are some products that have great industrial benefits.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of the conventional tertiary circuit cut-off method.
FIG. 2 is a circuit diagram of a transformer according to an embodiment of the present invention. 1: Primary winding, 2: Secondary output winding, 5: Secondary winding, 6: Primary winding, 7: Load disconnector, 21: Tertiary winding, 22: Secondary winding, 23: Tap winding, 2
4: Primary winding, 102: Series transformer, 103: Autotransformer, 201: Main transformer.

Claims (1)

[Scope of utility model registration request] A main transformer having a primary winding, a secondary output winding, and a tertiary winding, a series transformer in which the secondary winding is connected in series to the secondary output winding of the main transformer, and a tap changer that connects the an autotransformer that supplies power to the primary winding of the transformer via a tap winding switched by the tap changer, and a tertiary winding of the main transformer and the autotransformer that supplies power to the primary winding of the autotransformer; A load/disconnect tap switching transformer comprising a load/disconnect switch connected between the primary winding of a transformer.