JPH11202953A - Power transformer for energy saving - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely eliminate the fault of automatic control caused by feedback by serially inserting plural coils of transformers to a line, connecting both the terminals of the control element of an SCR to the secondary side of the transformer and controlling a voltage on the load side into arbitrary voltage by changing reactance on the primary side of the transformer. SOLUTION: Plural coils of transformers T are serially inserted to the line, both the terminals of the control element of the SCR or GTO are connected on the side of a secondary coil L2 among these plural coils of transformers T, and the voltage on the load side is changed into arbitrary voltage by changing the reactance on the side of a primary coil 1 among the plural coils of transformers T. Under such control, the load voltage is increased/decreased almost in ±20% as one of electric power saving measures. Thus, since the automatic control due to feedback is almost completed by an electronic circuit, the fault can be completely eliminated and the scale of install place can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a single-phase / three-phase power supply system, and as a part of energy saving measures, increases or decreases the secondary voltage to about ± 20% and controls the voltage to an arbitrary voltage. A device that saves power by maintaining a constant voltage automatically.

[0002]

2. Description of the Related Art Conventionally, a private customer who demands power of 50 KW or more generally negotiates a contract power with a power company and sets a condition for payment of an electric charge (basic fee). An extra charge was charged as a penalty for the excess power usage fee.

[0003] Therefore, each customer has come to install a demand control system as a power monitoring and control measure. However, since it is related to a three-phase power source in addition to a lamp power source, energy saving of a three-phase AC power source for an electric motor is also necessary.

The installation of the demand control system has been divided into the following types. (Ratio control method) When the contracted power is exceeded, the circuit is immediately cut off according to a preset order, and the power is used so as to be less than the contracted power. (Ideal curve method) The power required by the customer is set as an ideal curve, and the power load is adjusted and implemented along the curve. (Predictive control method) According to a change in power demand in a unit time, the last special room is predicted and the increase / decrease of the load is adjusted while comparing with the contract power.

[0005] In addition, when the reactance load is large,
There was a phase lag of the current, the power factor became worse, and wasteful power consumption (reactive power) increased, resulting in lower efficiency. These supplemented the waste of the power factor improvement by using the capacitance together.

In a small-scale device, an electronic circuit based on the electromagnetic theory of resonance uses a resonance circuit of a capacitance and a transformer, and a stable voltage is automatically controlled even when the load fluctuates greatly. Some devices were used.

[0007]

When the power is increased or decreased, a constant voltage cannot be obtained by compensating for the voltage fluctuation due to the fluctuation of the power supply voltage or the load. There was a case where it was desired to change the winding tap of the transformer according to the required voltage. However, the operation was not easy because of the high-voltage equipment.
Even more, in the case of large consumers of electricity, a power outage in the dark would hurt employment. Furthermore, it is impossible at all if it is a transformer tap conversion in a substation facility, and it is desirable to use automatic control.

[0008] Even with the same automatic control, there have recently been devices allegedly newly developed in the streets, but these are all devices that are merely applications of the technical ideas that have been in the past.

[0009]

[Means for Solving the Problems] It is generally accepted that the voltage adjustment in the substation equipment is performed directly by artificial work by switching with a winding tap (a secondary side voltage adjustment coil tap) attached to a main transformer. Met. However, all these devices
Irregular output voltage control by intermittent contacts by mechanical switches. With this, a stable arbitrary voltage cannot be obtained. In addition, it is not easy to obtain the correction of the voltage drop due to the fluctuation of the power supply voltage or the load, and it is preferable to insert a single-turn or multiple-turn transformer in series with the line, which responds quickly to the load fluctuation. It has been found. Of course, instead of mechanical control, a semiconductor SCR or an electronic VR variable resistor using a GTO control element is used.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a circuit configuration and a structure according to the present invention will be described with reference to the drawings. FIG. 1 is a diagram in which an M motor is connected to a general power source, and is operated by operating a SW main switch. FIG. 2 shows that in the case of a general high-power motor load, a large current flows at the time of rotation start, which adversely affects the circuit. Therefore, the switch is started by switching SW2 and SW3 (Y · Δ connection). In addition, as shown in FIG. 4, there are six types of constituent devices in total.

[0011] Other types of voltage control include direct start, star-delta start, reactor start, primary resistance start, condor fan start, and kiza start.

In lieu of these, the apparatus of the present invention shown in FIG. 3 has a very simple structure, and the circuit configuration is shown above. The following table shows the circuit configuration used for a single-phase power supply and a three-phase power supply. .
At the location indicated by T, a single-turn or multiple-turn transformer is inserted in series, and the voltage is increased or decreased by using a reactance change in the semiconductor control element. This principle is a method utilizing a voltage drop generated between both ends of a winding coil by the action of reactance. Since it is used as a voltage adjustment according to the present invention, fine adjustment is facilitated.

Further, since the electric power in the large-scale substation equipment is increasing, it is impossible to perform an artificial operation, and the operation must be automated. Therefore, in the automatic control by feedback, an arbitrary voltage is detected and set, and the potential is adjusted to the electric potential. The semiconductor control element automatically adjusts the change in reactance to perform the change.

[0014]

According to the present invention, the change in reactance is automatically adjusted by the semiconductor control element, so that an exaggerated structure is not required as in the prior art, and the installation place can be small. Since the automatic control based on the feedback is almost completed by an electronic circuit, the construction cost is almost zero and the construction cost is low.

[Brief description of the drawings]

FIG. 1 is a diagram in which an M motor is connected to a general power supply.

FIG. 2 is a circuit diagram of a Y.Δ starting operation circuit for a general high-power motor load.

FIG. 3 is a circuit diagram of the present invention and a circuit configuration comparison table when used for a single-phase power supply and a three-phase power supply.

FIG. 4 is a comparison table of various conventional motor starting methods.

[Explanation of symbols]

 SW1 Main switch CT Transformer transformer SW2 / SW3 Circuit changeover switch (Y / Δ) M Motor A Ammeter T Compound winding transformer L1 Primary coil L2 Secondary coil TA / TB Coil terminal SCR Rectification control element C Charging capacitor CC Rectifier Capacitor VR Variable resistor DA Diac R Resistor

Claims (3)

[Claims] (1) As part of power saving measures, a load voltage is set to ±
In order to increase or decrease the voltage up to about 20%, a multi-turn transformer is inserted in series in the circuit, and a secondary side of the transformer is connected to S
Connect between both terminals of CR or GTO control element,
A device that aims to save power by changing the reactance on the primary side of the transformer and controlling the voltage on the load side to an arbitrary voltage. 2. An SCR or GT in parallel with a primary or secondary coil of a transformer in order to change a reactance by inserting a single or multiple winding transformer in series in a power supply circuit.
A power saving device characterized by connecting a control element of O to control the voltage on the load side to an arbitrary voltage to increase or decrease the power on the load side. 3. The power saving device according to claim 2, wherein the reactance of the transformer can be automatically controlled by inputting a feedback signal using an SCR or a GTO element.