SU915071A1 - Current supply unit - Google Patents

Description

The invention relates to electrical engineering and can be applied at substations with variable operational current. * ~

Known power supply units containing an intermediate saturable transformer, one of the primary windings of which is connected to the input terminals, the secondary winding forms a ferro-resonance circuit with the capacitor and is connected via a rectifier bridge to the load [13.

The closest in technical essence to the present invention is a block containing an intermediate saturated transformer, the primary winding of which is connected to the input terminals, and the secondary forms a ferro-resonance circuit with a capacitor and is connected to the input of a rectifier bridge, the first of the output terminals of which is connected to the first output terminal, and choke [2].

2

A disadvantage of the known devices is the low reliability of the power, since the input current must be not less than the current of occurrence of ferroresonance, which is relatively large even in the idling mode of the block, this reduces the sensitivity of the block, besides going into the mode of ferroresonance at the input current arising under conditions of short short circuit on the protected connection, the power supply unit with current can remain in this mode if the load current of the protected connection exceeds the breakdown current of the ferroresonance. Therefore, when calculating the block, consideration should be given to the possibility of long-term heating of the steel core and the windings of the intermediate saturable transformer.

The purpose of the invention is to improve the reliability of power.

This goal is achieved by the fact that in the power supply unit with a current the working winding of the choke is connected

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915071

parallel to the capacitor, the first magnetizing winding is parallel to the output terminals of the rectifier bridge, the second biasing winding is connected to the second output terminal of the rectifier bridge by a second output terminal, and the other output terminal is connected to the second output terminal.

The drawing shows a schematic diagram of the device. ) 0

The device contains an intermediate saturable transformer 1, a capacitor 2, which, together with transformer 1, forms a ferroresonant circuit and an mbst rectifier 3, the input of which is connected in parallel to the ferroresonant circuit, and the output is connected to a load resistance 4. On the side of the clamps 5 parallel connection of the power supply unit , additional magnetizable choke 6, in which the working winding 7 is connected in parallel to the capacitor 2, the first biasing winding 8 2

through the resistor 9 is connected to the output of the bridge rectifier 3) and the second magnetizing winding 10 is connected in series with the load resistance 4. In addition, there may be a linear choke 11, which in high-power blocks is required to eliminate current resonance at the second and higher harmonics, when the current

the harmonics in the decreasing inductance of the saturable transformer 1 are compensated by the current in the capacitor 2 ·

The proposed device operates as follows.

Before the load current appears, the additional choke 6 is magnetized by the winding 8. The inductive current through the working winding 7 compensates for the capacitive current of the capacitor 2 in the chosen measure (50-60%), reducing the current at which the ferroresonance occurs at the fundamental frequency. In addition, for higher harmonics, the total reactance of the capacitor 2 and the working winding 7 of the additional choke differs little from the similar resistance of the capacitor.

As a result, after the onset of ferroresonance at the first harmonic, the voltage of the first harmonic on the ferroresonant circuit at the time of its maximum is opposite to the sign of the maximum of higher harmonics, and therefore no overvoltage occurs.

With the advent of current in the load resistance 4, additional choke 6 is magnetized by the difference of the ampere-turns of windings 8 and 10. The greater the current in load 4, the smaller the resulting magnetization of the choke 6, up to the unsaturated state. By reducing the capacitive current compensation by the choke 6, the current of the abrupt onset of ferroresonance increases, and c. conditions of optimal load of the block when the capacitor is selected ferroresonant jump disappears.

After the emergency mode is eliminated at the protected connection, the input current of the power supply unit decreases from the emergency power to the load current of the connection, the output current in load 4 also decreases due to the return of most relay protection and automation elements to a de-energized state. If, under these conditions, the proposed device does not leave the ferroresonance mode, then the voltage on the winding; Kakh intermediate saturable transformer 1 and the current in these windings is less than in the known device, because at least half the capacitive current of the capacitor 2

I is compensated for by the current of the operating winding 7 of the choke 6. The total losses in the secondary winding of the transformer 1 and the winding 7 of the choke 6 of the proposed device are less than known. Mr., because power is proportional to

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second current and two identical resistances with half current absorb half the power than the one with full current.

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In the proposed device, the stabilization of the voltage on the load 4 is improved. The following phenomena favor this. While decreasing

_{5 of the} load 4, on the one hand, the voltage drop from the load current in the secondary winding of the intermediate saturable transformer 1 decreases, and on the other hand, the supply voltage on the ferroresonant circuit decreases due to partial compensation of the capacitive current in the capacitor 2 by inductive current in the inductor 6. Biasing winding 10, manifesting itself as a choke,

⁵ reduces voltage fluctuations on

load when changing phase shift

between the input current proposed

device and voltage on a parallel operating power supply voltage.

The transients in the proposed device end relatively quickly, since the resistor 9 reduces the time constant of the inductively coupled bias windings 8 and 10.

Just as an intermediate saturable transformer 1 with a setting input current is a source of higher harmonics currents, a magnetized choke 6 with a setting input voltage generates a high-harmonic emf, but the currents they create are relatively small because the setting input voltage is limited by the voltage on the ferroresonance circuit from the transformer 1 and the capacitor 2, already for the first harmonic the inductive resistance of the magnetized inductor 6 is 2–1.67 times the capacitance of the capacitor 2, and for which Nicky still in K * once more.

Thus, the circuit features of the proposed power supply unit provide it with increased sensitivity to the input current, improved voltage stabilization at the load, and less heating during absenteeism.

507.1 6

from ferroresonance mode, which increases the reliability of power supply with current.

Claims (1)

Claims A power supply unit containing 5 an intermediate saturable transformer, the primary winding of which is connected to the input terminals, and the secondary forms a ferroresonant circuit with a capacitor and is connected to The input of the rectifier bridge, the first of the output pins of which is connected to the first output terminal, and the choke, characterized in that, in order to increase the power supply reliability, the working coil of the choke is connected in parallel to the capacitor, the first magnetizing winding is parallel to the output pins of the rectifier bridge, Secondly, the magnetizing winding is connected with one output to the second output terminal of the rectifier bridge, and the other output is connected to the second output terminal. 25