JPH0132346Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a gas insulated transformer with an on-load tap changer.

In recent years, insulating oil has been used as the insulating medium for this type of transformer in order to make it nonflammable.
There is a tendency to use insulating gases such as SF ₆ ,
This insulating gas has poor cooling efficiency compared to insulating oil, and cannot adequately cope with the heat generated by arcing and current limiting resistance during tap switching.

As a countermeasure against this, for example, as proposed for oil-immersed type (see Utility Model Publication No. 12267/1983), the transformer body and load tap switching element (hereinafter referred to as
It is called OLTC. ) could be made into independent forced circulation cooling systems, but this would require two cooling systems, which would be uneconomical.
Since the OLTC does not always perform tap switching operations continuously, it is not preferable to operate the cooling system on the OLTC side continuously from the viewpoint of operational efficiency, and conversely, the cooling system on the OLTC side is operated only when necessary. It is possible to control the cooling system so that it only operates for a certain period of time after OLTC operation, but this would make the cooling system on the OLTC side an idle facility except when necessary, which would be undesirable from the point of view of efficient operation of each facility. There is an inconvenience.

In view of the above-mentioned matters, this invention is designed so that the insulating gas sealed in the tank housing the transformer body and the chamber housing the OLTC circulates through a common cooler, and at least one By configuring a circulation path in which an adsorption chamber containing an adsorbent is provided between this chamber and the outward path of the cooler, and by controlling the solenoid valve based on the operation signal of the OLTC, In addition to improving the operating efficiency of the cooling system, this design also prevents the arc generated during OLTC operation from having an adverse effect on the transformer itself.

An embodiment of this invention will be explained below based on the drawings. 1 is a tank filled with an insulating gas such as SF ₆ , and a transformer main body 11 consisting of an iron core, coils, etc. is housed inside the tank. There is. 2 is a chamber separated from the tank 1, and this chamber 2 contains SF ₆
It is filled with an insulating gas such as, and an OLTC 21 having a current limiting resistance is housed therein.

3 is a cooler, and 31 is an air blower. A circulation path 4 connects the tank 1 and the chamber 2 to the cooler 3, and the insulating gas sealed in the tank 1 and the chamber 2 is circulated through the cooler 3 and cooled. At least one electromagnetic valve 41 is interposed between the chamber 2 and the cooler 3 in the circulation path 4, and an adsorption chamber 6 containing an adsorbent such as synthetic zeolite is provided on the outgoing path connecting the chamber 2 and the cooler 3. The opening and closing of the solenoid valve 41 is controlled by a control signal to be described later. 42 is a circulation blower that forcibly circulates the insulating gas. 5 is a control circuit for controlling opening and closing of the solenoid valve 41;
The solenoid valve 41 is opened based on the operation signal P for tap switching of the OLTC 21, and the solenoid valve 41 is closed after a certain period of time by a time-limited relay or the like. Therefore, when the solenoid valve 41 is opened, the insulating gas sealed in the chamber 2 circulates between the chamber 2 and the cooler 3 and is cooled, thereby cooling the inside of the chamber 2 . In this way, when controlling the opening and closing of the solenoid valve 41 using a time-limited relay, when the solenoid valve 41 is in the open state, the operation signal P for tap switching may be issued again. Instead of closing the solenoid valve 41 after a certain period of time from the operation signal P, for example, each time the operation signal P is input as a time limit relay, the previous time limit is cleared, and the final time when the solenoid valve 41 is in the open state is cleared. operation signal P
It is preferable to close the solenoid valve 41 after a certain period of time. In addition, the temperature inside the room 2 is detected by a temperature relay 51 installed in the room 2 instead of the time-limited relay,
The solenoid valve 41 may be closed when the temperature falls below a certain level. Note that P and P' are control signals.

The capacity of the cooler 3 and the air blower 31 is much smaller than that of the transformer body 11, and the time required for cooling the OLTC 21 is much smaller than that of the transformer body 11. If a slight temperature rise is allowed, then the capacity required to cool the transformer 11 can be used, and if the capacity required to cool the OLTC 21 is added to this, the added capacity can be used to constantly cool the transformer body 11. It can be effectively used to

In addition, if the OLTC 21 is of a type that transfers current using a non-electrical arc type switching element such as a vacuum switch or SCR, the insulating gas sealed in the chamber 2 will be affected by the arc accompanying the current transfer. This is advantageous because it prevents the metal from becoming contaminated and reduces the influence of temperature rise due to arc heat.

With the above configuration, the solenoid valve 41 is closed during operation of the transformer, and only the insulating gas sealed in the tank 1 is circulated through the cooler 3 and cooled.
This allows the transformer main body 11 to be cooled. Then, tap switching of the transformer is required, and OLTC2
When the operation signal P for tap switching to 1 is issued, this operation signal P is also input to the control circuit 5, and the solenoid valve 41 is opened. Therefore, the insulating gas sealed in the chamber 2 also flows through the circulation path 4 in the same way as the insulating gas in the tank 1.
The interior of the chamber 2, which was heated by the arc caused by the switching operation of the OLTC 21 and the heat generated by the current limiting resistor, is cooled, and the heat generated by this arc is cooled. Decomposed components such as decomposed gas are adsorbed by the adsorbent stored in the adsorption chamber 6 provided on the outward path connecting the chamber 2 and the cooler 3, so that this does not have any adverse effect on the transformer main body 11 side. Thereafter, the solenoid valve 41 is closed by the action of a timed relay or the like, and only the transformer main body 11 is cooled as before the tap switching operation signal P is issued.

As described in detail above, this invention has practical effects such as an extremely simple configuration, the ability to share a cooler, efficient operation, and extremely economical performance.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an embodiment of this invention. 1: Tank, 11: Transformer body, 2: Room, 2
1: On-load tap switching element (OLTC), 3: Cooler, 4: Circulation path, 41: Solenoid valve, 5: Control circuit,
P: Operation signal.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A tank that houses a transformer body, a chamber that is separated from the tank and houses a load tap switching element, and a cooler that shares the insulating gas sealed in the tank and the chamber. The circulation path is formed to circulate and has at least one solenoid valve interposed between the chamber and the cooler, and an adsorption chamber containing an adsorbent in the outward path between the chamber and the cooler. . A gas insulated transformer with an on-load tap changer configured to control opening and closing of the solenoid valve based on an operation signal of the on-load tap changer element. 2. A gas insulated transformer with an on-load tap changer according to claim 1, wherein the solenoid valve is closed after a certain period of time by a time relay. 3. A gas insulated transformer with an on-load tap changer according to claim 1 of the utility model registration, wherein the electromagnetic valve is closed when the temperature falls below a certain level by a temperature relay placed indoors.