JPS60167409A - Oil immersed transformer with power factor improving apparatus - Google Patents

Abstract

PURPOSE:To form a compact transformer and improve reliability in operation by installing the major part of power factor improving apparatus and the transformer body in the tank in the manner that these are together immersed in the insulation oil. CONSTITUTION:A power factor improving apparatus 2 is composed of a phase-lead capacitor 3 used as the power factor improving element, a series reactor (formed by an iron core and a coil) 4, a thyristor 5 used as an ON-OFF element and a frame 2a supporting them and this apparatus is immersed in the insulation oil 8 in the tank 9 together with the transformer body 1. The transformer body 1 comprises the primary side in star connection and the secondary side in delta connection and the output of secondary side is connected to an external load through the bushing 10. A reactive power relay 6 which gives the ON-OFF signals to the thyristor 5 receives a current signal and a voltage signal from the respective signal lines connected to the other two output lines of the secondary output leads as in the case of a current transformer 7 wound to an output line of the secondary leads of transformer body. This relay 6 is arranged at the outside of a tank 9 and forms the power factor improving apparatus together with the elements 3, 4 and 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a fine voltage transformer incorporating a power factor correction device.

[Background of the invention]

When using an inductive load such as a motor, the power factor of the load may deteriorate and the effective power supply capability may decrease. Therefore, the capacity of the transformer needs to be larger than the load capacity, which is uneconomical for transformer customers. As a measure to improve the power factor, it is common to insert a phase advance capacitor in parallel with the load to increase the capacity, but if the transformer and phase advance capacitor are separate, the installation area becomes large, and conventional off-the-shelf transformers There are problems such as the terminals being oriented incorrectly and the wiring work complicated. Furthermore, there were problems with electrical safety due to the routing wires, insulation reliability due to dust adhesion, etc. [Objective of the Invention] In view of the above points, the object of the present invention is to reduce the installation space and facilitate the wiring work. An object of the present invention is to provide an oil-immersed transformer with a power factor correction device.

[Summary of the invention]

According to the present invention, a power factor correction device is housed in a tank in which a transformer body is housed, immersed in oil.

[Embodiments of the invention]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, in which 1 shows a three-leg iron core 1a and three coils 1b to 1d wound around each leg.
2 is a power factor correction device arranged at the bottom of the tank below the base 1e of the transformer main body 1, which includes a phase advance capacitor 6 and a series reactor (iron core and coil) as power factor correction elements. ) 4. It is composed of a thyristor 5 as a switching element and a frame 2a that supports them, and is immersed together with the transformer body 1 in insulating oil 8 in a tank 9. The transformer main body 1 has a star connection on the primary side and a delta connection on the secondary side, and the output on the secondary side is connected to bushing 1.
0 to an external load. 6 is a reactive power relay that provides ON/OFF signals to the thyristor 5;
Current transformer 7 wound around one of the secondary output wires of the transformer body
Similarly, it receives a current signal and a voltage signal from the signal lines connected to the other two secondary output lines. This relay 6 is arranged outside the tank 9, and constitutes a power factor correction device together with the above elements 6, 4, and 5.

FIG. 2 is a circuit diagram of the same embodiment, and the same parts as in FIG. 1 are designated by the same reference numerals. The power factor correction device M2 is constituted by four delta connection circuits connected in parallel to the secondary side output line, as surrounded by a broken line. Since square loads generally have inductive reactance, it is necessary to compensate for this. The delta connection circuit constituted by the phase advancing capacitor 3a is provided as a basic circuit for this compensation, and is fixedly connected without intervening a switching element such as a thyristor. Note that an accelerator having a fixed value may be connected in series to the capacitor 3a.

In the other three delta connection circuits, a thyristor 5 is connected in series to a circuit element on each side, for example 61. The thyristor 5 is turned ON by the relay 6 depending on the power factor of the load.
closed by a signal being supplied to the base terminal,
A compensation circuit having an appropriate phase advance capacitor capacity is constructed by connecting a delta connection circuit having the element 61 in parallel to the basic delta connection circuit described above. Thyristors are also connected in series in the delta connection circuit consisting of elements 32 and 33, and are connected in parallel to the base delta connection circuit depending on the power factor of the load, and the value of the capacitor and accelerator is adjusted according to the load. Configure a compensation circuit with

The relay 6 determines the power factor state of the load based on the degree of phase shift between the current and voltage based on the current signal and voltage signal from the output line on the secondary side. Pulsed ON, O to the gate terminal of
Gives FF signal.

Therefore, three types of ON and OFF signals are required for each division in one delta connection circuit, and in the example of Fig. 2, there are 81 types of 9 types in total.
~S9 is required.

The capacitor 3, reactor 4, and thyristor 5 shown in FIG. 1 include corresponding elements shown in FIG. 2.

In the above embodiment, as is clear from the figure, the inside of the tank 9 is
Since almost all of the electric circuit parts are immersed in the insulating oil 8, electrical insulation and heat dissipation between the circuits are excellent, and each component can be arranged close to each other to achieve compactness. Further, since the wiring between each electric circuit is conducted inside the tank, it is easy to connect the lead wires when the electric circuit is installed in the cubicle. Furthermore, although the transformer body is a heat source, since it is disposed above the tank, the influence of heat on the power factor correction device 2 can be reduced, and the operational reliability of the device 2 can be improved.

FIG. 6 shows another embodiment. In this example, frame 2
A phase advancing capacitor 3 is arranged vertically inside the frame 2a, and a thyristor 5 is arranged at the bottom of the frame 2a.

According to this embodiment, the convection of the insulating oil between the capacitors 6 is improved, and the thyristor 5, which is sensitive to heat, can be provided at the bottom where the temperature is lowest in the tank, so the operation of the power factor correction device 2 is stabilized. The performance can be improved by -i.

Note that the location and direction of arrangement of the series reactor 4 shall be selected so as not to be affected by the magnetic influence of the transformer main body.

〔Effect of the invention〕

According to the present invention, the main parts of the power factor correction device are installed in a tank immersed in insulating oil together with the main body of the transformer.
The transformer can be configured compactly and its operational reliability can be improved.

Furthermore, wiring work can be facilitated when the transformer is assembled into the cubicle.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIG. 2 is a circuit configuration diagram, and FIG. 3 is a longitudinal sectional view of another embodiment. 1: Transformer main body, 2: Power factor correction device, 3: Phase advance capacitor, 4: Series reactor, 5.4: Power factor correction element, 5
: Switching element, 8: Insulating oil, 9: Ri Figure 1

Claims (1)

[Scope of Claims] 1. A transformer main body consisting of a winding and an iron core, a power factor correction device including a power factor correction element such as a phase advance capacitor and a series reactor, and connected in parallel with the secondary winding of the transformer main body. An oil-immersed transformer with a power factor correcting device, comprising a tank that houses the transformer main body and the power factor correcting device immersed in insulating oil. 2. The power factor correction device includes a plurality of sets of power factor correction elements, and any set of power factor correction elements connected to the secondary winding according to the power factor of the load connected to the secondary winding. An oil-immersed transformer with a power factor correction device according to claim 1, comprising a switching element that separates the switching element. 3. Claim 1 or 2, wherein the power factor correction device is arranged below the transformer main body in the tank.
Oil-immersed transformer with power factor correction device as described in .