JPS61199419A - Transformer for instrument - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an instrument transformer equipped with a saturable reactor.

[Technical background of the invention and its problems]

Potential transformers that are directly connected to the ground system have a phase difference when the circuit breaker is opened based on the capacitance between the poles of the circuit breaker, the ground capacitance of the system, and the inductance and resistance of the voltage transformer. Under certain conditions, ferro-resonance occurs, and the iron core becomes extremely saturated at 1/3 to 115 frequencies, causing a large excitation current to flow, which may burn out the windings of the voltage transformer.

In order to suppress such ferro-resonance, a saturable reactor is connected in parallel with the secondary winding, so that the saturable reactor saturates earlier than the iron core of the potential transformer saturates at the initial stage of occurrence of ferro-resonance.

The saturation of the saturable reactor handle causes a large current to be generated in the secondary winding, thereby changing the inductance and resistance on the downstream side of the potential transformer, thereby quickly terminating the condition in which fero-resonance occurs.

Conventionally, as shown in FIG. 4, a primary winding 1 and a secondary winding 3 are wound around an iron core 2 and housed inside an airtight container 8, and insulation such as SF6 gas or insulating oil is applied inside the airtight container 8. On the secondary side of the instrument transformer, in which the medium 9 is sealed and the respective secondary and secondary windings are led out through the sealed terminal 4 provided in the sealed container 8, there is a protective A load 7 such as a relay necessary for protecting the system is connected via the fuse 5a. A saturable reactor 1 and 6 were connected in parallel to the secondary winding 3 on the air side. For this reason, there has been concern about the capacity of the protective fuse 5a or the insulation of the saturable reactor 1-6.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and its purpose is to obtain high reliability with respect to concerns about the capacitance of a protective fuse and the insulating properties of a saturable reactor. The object of the present invention is to provide an instrument transformer having a small switchboard and requiring less wiring work.

[Summary of the invention]

In order to achieve the above object, according to the present invention, an iron core wound with primary and secondary windings is housed in a sealed container, an insulating medium is enclosed, and the iron core is connected in parallel with the secondary winding as an equivalent circuit. By connecting the saturable reactor 1- to the saturable reactor 1-, and connecting one sealed terminal of the secondary winding and one sealed terminal of the saturable reactor 1- to the outside of the sealed container, the saturable reactor 1 to In addition to improving the insulation performance of the device, the protective fuse can be set based only on the load, and it also improves workability and reliability.

[Embodiments of the invention]

Hereinafter, one embodiment of the voltage transformer of the present invention will be described with reference to the first part. The same parts as in FIG. 4 are given the same reference numerals. That is, the iron core 2 is wound with the primary winding] and the secondary winding 3 and stored in a sealed container 8, and the SF is placed in the sealed container 8.
6 Fill with an insulating medium 9 such as gas or insulating oil. Then, the secondary winding 3 and the secondary winding 3 are led out from the sealed container 8 through the sealed terminal 4, and the AC 1 coil 6 is saturated in parallel with the secondary winding 3 in the sealed container 8.
Connect. That is, one end of the saturable reactors 1 to 6 is connected to the secondary winding 3 inside the sealed container 8, and the other end is led out to the outside via the sealed terminal 4a, and is connected to one sealed terminal of the secondary winding 3. 4 through a connecting wire 10 outside the closed container 8. A burden 7, such as a relay, is then connected from the sealed terminals 4, 4 on the secondary side via fuses 5, 5, respectively.

Next, the effects of the present invention will be explained. The saturable heating element 6 is housed in a sealed container 8, and is insulated together with the primary and secondary windings 1 and 3 wound around the iron core 2, and an insulating medium 9 is inserted therein. The reliability of the insulation of the saturable reactor 6 can be improved. In addition, since the saturable reactors 91 to 6 are directly attached to the secondary winding 3 without being attached to the switchboard, even if the saturable reactor 6 is saturated and a large current flows, it has nothing to do with the fuse 5. Therefore, the capacity of fuse 5 is 7
It can be determined only by the size of . Further saturable react 1
A part of the connection between the coil 6 and the secondary winding 3 is sealed with the terminals 4, 4a.
By connecting the line 10 with the saturable reactor 1
By disconnecting the connecting wire 10, the coil 6 can be tested independently, and the saturable reactor 1 cell 6 can be protected from the voltage rise during the induced withstand voltage test.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as in FIG. 1 are given the same reference numerals. In other words, a saturable reactor 1 and a ferro-resonance suppressing winding 1 are placed in a sealed container 8.
One side of the series circuit with 1 is connected to the - power of the secondary winding 3, one side of the saturable reactor 1 is led out through the sealed end 7-4a, and the - power of the secondary winding 3 is Sealed terminal 4 and connection FA1.
0 to the outside of the closed container 8. This saturable reactor 6 is connected in parallel with the secondary winding 3 in a primary or secondary equivalent circuit. Even in such a second embodiment, the same effects as in the first embodiment can be obtained.6 Furthermore, a third embodiment of the present invention will be described with reference to FIG. The same parts as in FIG. 1 are given the same reference numerals. That is, in the split type having the iron core 2, the negative and secondary windings 1 and 3 are wound, and the auxiliary secondary winding 12 and the balance winding 13 are also wound.

By connecting the saturable reactors 1 to 6 in parallel to this balanced winding 13 and storing them in a closed container (not shown), the saturable reactors 1 to 6 can be insulated as in the first embodiment of the present invention. The capacity of the fuse can be selected only according to the load. Note that the saturable reactor 6 is connected to the secondary winding 3 in the equivalent circuit of primary or secondary conversion.
are inserted in parallel.

〔Effect of the invention〕

As explained below, according to the present invention, the saturable reactor 1
By incorporating the module into a sealed container, the insulation performance is improved, a special switchboard is not required, and there is no risk of fuse blowing due to the excitation current when the saturable reactor is saturated, resulting in an instrument with improved reliability. It can be provided to the transformer for use.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a voltage transformer according to the present invention, FIG. 2 is a circuit diagram of a second embodiment of the present invention, FIG. 3 is a circuit diagram of a third embodiment of the present invention, and FIG. 1 is a circuit diagram of installing a saturable reactor using a conventional potential transformer. 1 - Secondary winding 2... Core 3... Secondary winding 4, 4a... Sealed terminal 5, Fuse 6... Saturable reactor 7 Burden
8... Airtight container 9 - Insulating medium 10 - Connection wire 11... Ferro-resonance suppression winding 12 Sub-secondary winding 13 - Balance winding Figure 1 Figure 2

Claims (1)

[Claims] In an instrument transformer in which a primary winding and a secondary winding are wound around an iron core and housed in a container together with an insulating medium, a saturable reactor is connected in parallel to the secondary winding as an equivalent circuit, and a saturable reactor is connected in parallel to the secondary winding as an equivalent circuit. an instrument transformer, wherein one sealed terminal of the secondary winding and one sealed terminal of the saturable reactor are connected on the outside of the container.