JPS645448B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to shunt reactors.

Low voltage control is applied to the shunt reactor for the purpose of omitting the use of multiple high voltage switches and disconnectors for switching the shunt reactor, which are required when the shunt reactor is directly connected to the power line. Provide a winding,
It is known that by short-circuiting and opening this, the path of magnetic flux is controlled, and the slow phase capacity as a shunt reactor is equivalently controlled. 1st
2 shows an example of the structure, in which a main winding 2 is wound around a main iron core 1, and a control winding 3 is wound inside the main winding 2. Further, both ends of the main core 1 are magnetically short-circuited by yoke cores 4A and 4B to form a closed magnetic path. The main winding 2 is directly connected to the line, and a short circuit switch 5 is connected between both ends of the control winding 3.

According to this configuration, as shown in FIG.
When the yoke is open, all of the magnetic flux generated according to the voltage of the line passes through the main core 1 and circulates through each yoke core 4A, 4B as shown by the dotted line. When the switch 5 is closed and the control winding 3 is short-circuited as shown in FIG. commutation) and returns via the yoke cores 4A and 4B. As a result, the magnetic resistance increases significantly, and a magnetizing current flows through the main winding 2 to compensate for this. This generates large delayed reactive power. By selectively opening and closing the switch 5 as described above, it is possible to adjust the delayed reactive power of the line to which this shunt reactor is directly connected.

However, as can be understood from the above explanation, when the switch 5 is closed, no magnetic flux passes through the main core 1, but when it is opened, all the magnetic flux passes through it, so the main core 1 , must be the cross-sectional area necessary for this magnetic flux to pass through. Also, since the main winding 2 and the control winding 3 are wound around the main core 1, the larger the cross-sectional area of the main core 1, the larger the dimensions and weight of each winding, and the greater the loss. comes out.

This invention reduces the cross-sectional area of the main core, reduces weight,
The purpose is to reduce dimensions, losses, etc.

This invention attempts to achieve the above object by using an iron core with a gap in the main iron core.

Embodiments of the present invention will be described with reference to FIG. 3 and subsequent figures. Note that parts with the same reference numerals as in FIG. 1 refer to the same or corresponding parts. As described above, in this invention, the main iron core 1 uses an iron core having a gap 11. Specifically, the main core 1 is constructed by stacking a plurality of block cores 12 in a column shape with gaps 11 interposed therebetween.

In the above configuration, when the switch 5 is opened as shown in FIG. 3, a considerable amount of the magnetic flux φa of the magnetic flux generated according to the line voltage flows through the main iron core 1 as shown by the dotted line in the figure. street, yoke iron core 4A,
However, since the magnetic resistance of the main core 1 is greatly increased due to the presence of the gap 11, a part of the magnetic flux φb does not pass through the main core 1 as shown by the dotted line and flows back through the main core 1. It passes through the space outside of the yoke iron cores 4A and 4B and returns to the yoke cores 4A and 4B.

Next, as shown in FIG. 4, when the switch 5 is closed, the magnetic flux φa that had previously passed through the main core 1 passes through the space outside the main core 1 and the yoke core 4A, as shown in FIG. It becomes reflux after passing through 4B,
At this time, the magnetizing current increases more than before, and a large delayed reactive power is generated.

If we compare the cases in Figure 1 and Figure 3, in the case of Figure 1, the entire generated magnetic flux passes through the main iron core 1, whereas in the case of Figure 3, the magnetic flux φa passes through the main iron core 1. The amount of magnetic flux φb is smaller than the total magnetic flux. The magnetic flux density of the main core is not affected much by the presence or absence of a gap, so the cross-sectional area of the main core 1 shown in Figure 3 is made smaller than that of the main core 1 shown in Figure 1 to compensate for the decrease in magnetic flux passing through. You will be able to do so.

To explain this in more detail, if the total magnetic flux now generated is φ, the magnetic resistance of the main iron core 1 is Ra, and the magnetic resistance of the space outside the main iron core 1 is Rb, then the main iron core 1
The magnetic flux φa passing through is expressed as φa=Rb/Ra+Rb×φ. This type of shunt reactor is designed so that when the switch 5 is closed, all of the generated magnetic flux passes through the space outside the main iron core 1, so the magnetic resistance Rb is relatively small, and therefore the Rb
It is relatively easy to set <Ra. Therefore, it is possible to satisfy the relationship φa<φ/2. On the other hand, as mentioned above, the magnetic flux density of the main core 1 is not affected much by the presence or absence of the gap 11, so
It is also possible to reduce the cross-sectional area of the main core 1 to less than half that of the main core without a gap shown in FIG.

In the case of Figure 1, all the generated magnetic flux is at the main core 1.
In contrast, in the case of Figure 2, all the magnetic flux passes through the space outside the main core 1, so the adjustment of delayed reactive power by opening and closing the switch 5 is a two-stage control of 0 capacity and full capacity. . However, in the case of FIG. 3, even when the switch 5 is opened, the magnetic flux φb does not pass through the main iron core 1, so in this case, the capacity does not become 0 as in FIG. 1. Therefore, two-stage control is performed: a certain capacity excluding 0 capacity, and full capacity. What is the capacity here?
This is an arbitrary capacity determined by the design of the gap 11.

The block core 12 may be a laminated core with a rectangular cross-section, but in order to increase the porosity, it may be a stepped core or a laminated core with a circular cross-section as shown in FIG. Furthermore, a radial core having a circular cross-sectional shape as shown in FIG. 6 or an involute core as shown in FIG. 7 may be used.

As detailed above, according to the present invention, the cross-sectional area of the main core can be reduced compared to conventional ones, so not only the main core but also the main winding and control winding can be made smaller and lighter. This makes it possible to reduce losses during operation.

[Brief explanation of drawings]

1 and 2 are configuration diagrams of a conventional example, FIGS. 3 and 4 are configuration diagrams showing an embodiment of the present invention, and FIGS. 5 to 7 are sectional views of the iron core block. 1... Main iron core, 2... Main winding, 3... Control winding, 4A, 4B... Yoke iron core, 5... Switch,
11...gap, 12...block iron core.

Claims (1)

[Claims] 1. A shunt reactor in which a control winding whose ends are selectively short-circuited and opened, and a main winding surrounding the outside of the control winding are wound around a main core whose ends are magnetically short-circuited by a yoke core. In the shunt reactor, the main iron core is provided with a gap.