JPS6342503Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a capacitor-type voltage transformer having a resonant secondary short-circuit protection device, and is aimed at making the transformer smaller and more economical.

A potential transformer having a circuit configuration as shown in FIG. 1 has conventionally been configured as shown in FIG. 2. That is, the main capacitor C1, the main voltage dividing capacitor _C2 , and the sub voltage dividing capacitor _C3 connected in series between the high voltage terminal _U and the ground terminal V are all housed in the insulator tube container 1, and the main transformer _Trn The main resonant reactor L _n , the sub-transformer T _ra and the sub-resonant reactor L _a are housed in an oil-filled tank 2, and the main resonant capacitor constituting the resonant secondary short-circuit protection device.
C _pn and sub-resonant capacitor C _pa were sealed in a can-shaped container 12 as shown in FIG. 3 and stored in an accessory tank 3.

In this way, in the conventional case, the main capacitor C ₁ , the main partial voltage capacitor C ₂ and the auxiliary voltage dividing capacitor C ₃ are housed in the insulating tube container 1, so the voltage dividing terminals h, h' and the low voltage It was necessary to provide a terminal l. For this reason, it was not possible to use a common porcelain tube container with a capacitor-type voltage transformer that does not include a sub-transformer consisting of a sub-voltage dividing capacitor _C3 , _a sub-resonant reactor, and a sub-transformer Tra.

In addition, the voltage applied to the main resonant capacitor C _pn and the auxiliary resonant capacitor C _pa is C ₁ to _{C 3} when a secondary short circuit occurs.
Therefore, terminals 5 and 8 for drawing out from the oil tank 2, and terminal 13 shown in Fig. 3 of the resonant capacitors C _pn and C _pa are connected to high voltage withstand voltage with large bushings. I need something expensive,
Furthermore, since it is necessary to provide a large air insulation distance within the accessory tank 3, the accessory tank 3 itself becomes large and expensive.

The present invention eliminates these drawbacks, and examples thereof will be described below. In this invention, the fourth
As shown in the figure, the main capacitor is installed in the insulator tube container 1.
Only C ₁ and the main partial voltage capacitor C ₂ are stored, and the auxiliary voltage dividing capacitor C ₃ is installed in the oil-filled tank 2, and its high pressure side is connected to the main voltage dividing capacitor C ₂ via the terminal l at the bottom of the insulator tube container 1. The low voltage side is connected to the accessory tank 3 through the terminal 9 and to the ground terminal V along with the low voltage side of a sub-resonant reactor _{L a} to be described later.

Similarly, in the oil tank 2, the main transformer T _rn connects the high voltage side of the primary winding to the connection point between the main capacitor C ₁ and the main voltage dividing capacitor C ₂ via the terminal h at the bottom of the insulating tube container 1. At the same time, the low voltage side is connected to the low voltage side of the sub voltage dividing capacitor _C3 through the main resonant reactor _Ln . In addition, a main resonant capacitor C _pn and _a main arrester G _n , which are connected in series with each other, are connected in parallel to the main resonant reactor L _n .
G _n is stored in the accessory tank 3, and one end is the terminal 10.
The main resonant capacitor C _pn in the oil tank 2 through
, the other end is connected to the main resonant reactor L _n via terminal 6.
Connect to the low pressure side of each. In addition, the main transformer
The secondary side of _Trn is taken out into the accessory tank 3 via the terminal 4.

Furthermore, in the same way, in the oil tank 2, the auxiliary transformer
T _ra connects the high voltage side of the primary winding to the high voltage side of the auxiliary voltage dividing capacitor C ₃ , and connects the low voltage side to the ground terminal V from the terminal 9 through the auxiliary resonant reactor L _a as described above. In addition, the sub-resonant reactor
Of the sub-resonant capacitor C _pa and sub-arrester G _a that are connected in parallel to L _a and are connected in series, the sub-resonant capacitor C _pa is stored in the oil tank 2, and the sub-arrester G _a is stored in the accessory tank 3. one end is connected to the sub-resonant capacitor C _pa via terminal 11,
The other end is connected to ground terminal V. In addition, the sub-transformer
The secondary side of _Tra is taken out into the accessory tank 3 via the terminal 7.

In this case, the auxiliary partial voltage capacitor _C3 , the main resonant capacitor _Cpn , and the auxiliary resonant capacitor _Cpa provided in the oil tank 2 do not need to be enclosed in a can-shaped container.
For example, as shown in FIG. 5, a flat, cloth-shaped capacitor element 14 is sandwiched between insulators 15,
It has a structure in which it is tightened from the outside with a tightening plate 16 and bolts 17.

Next, the configuration of the present invention is such that the auxiliary partial voltage capacitor _C3 is housed in a container, for example, an oil tank ₂ , separate from the insulator tube container 1 that houses the main capacitor _C1 and the main partial voltage capacitor C2. Furthermore, the effect of housing the main resonant capacitor C _pn and the auxiliary resonant capacitor C _pa in the same oil-filled tank 2 will be explained.

(1) By storing the auxiliary partial voltage capacitor C ₃ in an oil-filled tank 2 separate from the insulator tube container 1, the capacitance between the main capacitor C ₁ and the main voltage dividing capacitor C ₂ is reduced due to the temperature difference between the containers. Errors due to changes in are a problem. However, in practice, the error class of the sub-transformer is at most about class 3.0, or even lower. Therefore, these capacitors
If the same dielectric material is used for C ₁ to _{C 3} , errors due to changes in capacitance of the capacitor due to temperature differences between the containers will be negligible, as will be described later. Therefore, the sub voltage dividing capacitor _C3 is
It is possible to save money by storing the main capacitor C ₁ and the main partial pressure capacitor C ₂ in a container such as an iron tank that is separate from the insulator container that stores the main capacitor C 1 and the main partial pressure capacitor C 2 . In other words, for example, if the temperature coefficient of capacitance of a capacitor is |2|×10 ^-4 /℃ and the temperature difference between containers is 10℃, the error with respect to the rated value of capacitance is 0.2
%, which is so small that it does not pose a problem for its error class of 3.0.

In this case, (i) Since the insulated tube container is more expensive than the iron tank, by housing the sub-divided voltage capacitor _C3 in the iron tank, the insulated tube container 1 is made smaller and the same as the system without the sub-divided voltage capacitor. Therefore, a capacitor-type potential transformer with a sub-transformer can be constructed economically.

(ii) The insulator tube container 1 having two low voltage terminals l and one partial voltage terminal h at the bottom is widely used as a standard and easily available. In the present invention, an instrument transformer with an auxiliary transformer can be constructed using this standard-structured insulating tube container.

(iii) When converting an existing general voltage transformer without a sub-transformer into a voltage transformer with a sub-transformer as shown in Figure 1, the existing capacitor part can be used as is if the present invention is used. be able to.

(2) In order to house the main resonant capacitor C _pn and the auxiliary resonant capacitor C _pa together with the main transformer _Trn , etc. in the common oil tank 2, the terminals 5 and 8 with high voltage bushings in Fig. 2 are shown in Fig. 4. The terminals 10 and 11 can have low withstand voltage. Furthermore, these resonant capacitors and sub-voltage dividing capacitor _C3 can be used as capacitor elements without being enclosed in a can-shaped container equipped with a large bushing terminal 13, and the accessory tank 3 can also be used inside. Since it is not necessary to take a large distance for air discharge, the size can be reduced.

As explained above, when the present invention is used, it is possible to reduce the size of the insulating tube container and other parts of this type of equipment, and to make it more economical.In addition, it can be applied to the modification of conventional equipment to include a sub-transformer, and has great effects. can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a capacitor type potential transformer with a sub-transformer, Fig. 2 is an explanatory diagram showing the conventional configuration of this type of device, and Figs. A front view and a side view, FIG. 4 is an explanatory view showing the configuration of an embodiment of the present invention, and FIG. 5 is a front view showing a capacitor used therein. 1...Insulator tube container, C ₁ ...Main capacitor, C ₂ ...
...Main voltage dividing capacitor, C ₃ ...Sub voltage dividing capacitor,
C _pn ...Main resonant capacitor, C _pa ...Sub-resonant capacitor, T _ra ...Sub-transformer, T _rn ...Main transformer, L _n
...Main resonant reactor, L _a ... Sub-resonant reactor, V ... Ground terminal, U ... High voltage terminal, G _n ...
Main arrester, G _a ... secondary arrester.

Claims (1)

[Scope of utility model registration request] A main capacitor, a main voltage dividing capacitor, and a sub voltage dividing capacitor are connected in series from the high voltage terminal to the ground terminal, and each of the main capacitor and the main voltage dividing capacitor, and the main voltage dividing capacitor and the sub voltage dividing capacitor are connected in series from the high voltage terminal to the ground terminal. In a capacitor-type voltage transformer equipped with two sets of resonant secondary short-circuit protection devices each connected between a connection point and the ground terminal, the main capacitor, the main voltage dividing capacitor, and the sub voltage dividing capacitor are connected to each other. The sub-voltage capacitor and the resonant capacitor of each resonant type secondary short-circuit protection device and the resonant capacitor and A capacitor-type instrument transformer characterized by housing a resonant reactor.