SU1206883A1 - Symmetrizing-compensating device - Google Patents

Description

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The invention relates to power engineering and can be used for balancing voltages and currents under asymmetrical loads, as well as for sensing reactive power in a three-phase network.

The purpose of the invention is to extend the functionality by smoothly adjusting the current of the forward sequence in magnitude and extending the range of current control of the reverse sequence in magnitude and angle.

The drawing shows a diagram of a symmetric compensating device.

The device contains the phases of the primary winding 1, a transformer with a rotating magnetic field, the phases of the secondary winding 2, reactive resistances 3-5. The outputs of the phases of the secondary winding through the resistance 3-5 are connected to the same terminals of the phases of the primary winding.

The device works as follows.

When connected to an electrical rephase network with different active resistances, the device consumes direct and reverse currents, and when the angle of rotation of the secondary winding changes, the forward sequence is

varies in magnitude from zero to the maximum value determined by the total value of reactances, and the negative-sequence current varies in angle with the angle of rotation of the secondary

windings.

The phases of forward and reverse sequence currents depend on the type of resistance 3-5. If the resistances are capacitive, then the direct current sequence is capacitive, and the phase of the negative sequence current changes synchronously with the angle of rotation of the secondary winding plus angle (about + 90), where l is determined by the distribution of capacitances over the load resistance VNIIPI Order PCT Subscription Branch Patent, Uzhgorod, Proektna St., 4

2068832

If the resistances are inductive, then the direct sequence current is inductive, and the negative sequence current varies in phase 5 synchronously with the angle of rotation of the secondary winding plus angle (about -90), where about is determined by the distribution of shujktivnosti over load resistances.

, 10 When the device is connected to a three-phase electrical network, it consumes a direct sequence current

h

defined by the formula:

, -J | i

 and, / e

(

I

411

Uc

2ei (((

k

k

n -It Itl)

and the negative sequence current J defined by the formula:

lM.1 ,,.

. g z1 k k2 .- nr

: 3

JP

where and

j T k.

il. -i

jZj Zji nt

2t, hjj, z i, j voltage direct and reverse sequence of the network, load resistances;

k - transformer transformation ratio; p is the angle of rotation of the transformer.

From the analysis of the formulas, it can be seen that the direct sequence current is determined mainly by the values 2i, n iii QI also by the angle / 3, and the negative sequence current is determined by the quantities Zj, g, Zjjj, / 3, as well as the distribution of resistance across the phases. When resistance is odipat.

one

- 2

III

arrange

The structure smoothly adjusts when changing the angle p only the amount of current in the direct sequence.

The proposed device for balancing allows obtaining a negative sequence current of any magnitude and phase and a direct sequence current of any magnitude.

Claims (1)

SYMMETRIC COMPENSATING DEVICE containing phases of the primary and secondary windings of a transformer with a rotating magnetic field and load reactances, characterized in that, in order to expand the functionality by continuously regulating the current of the forward sequence in magnitude and expanding the range of regulation of the current of the reverse sequence in magnitude and angle, phase the secondary winding of the transformer through reactance connected to the same phases g of the primary winding, and the aforementioned reactances are chosen unequally. SU,. „1206883