DE2034638A1 - Arrangement of a step regulating winding for 90 degree cross regulation with star and open circuit in three-phase transformers - Google Patents

Description

Arrangement of a step regulating winding for 90o cross regulation with star and Open circuit in three-phase transformers The invention relates to the arrangement a step control winding, which is used for 90o cross regulation of star or open switched Windings in three-phase transformers can be used.

In some cases, the use of three-phase transformers with cross regulation required when different networks, whose voltage yect-oren-.not have the same phase position, are interconnected by transformers should. In such a case the phase rotation of the two networks can be mutually exclusive only . be compensated by a cross adjustment. Through such compensation and the equalization of the absolute voltage values (through longitudinal regulation) becomes a good interaction of the networks possible.

For 90o cross regulation of three-phase transformers, the to be regulated. Windings in star or open circuit hitherto various known Circuits used.

These known circuits are mostly through connections of Main and auxiliary transformers with the VDE and foreign regulations on- . shown vector groups reached.

For comparison with the innovation described later, Fig.1 and Fig.2 such circuits are shown vectorially. Fig.1 shows a circuit Yy0 with 90o cross regulation.

The longitudinal regulation takes place directly in connection with the one to be regulated Main transformer winding (HT). A second control winding in the main transformer feeds an additional transformer (ZT), the 90o phase shifted by the circuit DIII Generates voltages and transfers them to the control loop.

Fig. 2 also shows a circuit Yy0 with 90o cross regulation. Longitudinal and transverse regulation are directly connected to the winding to be regulated. Both control windings are located outside the main transformer (HT).

With this circuit, two additional transformers (ZT1 and ZTG) are required, one for the longitudinal regulation and one for the 90 degree transverse regulation. The 90o cross regulation of a three-phase transformer, at where the windings to be controlled are star or open circuit is, according to the current state of the art, only with INAn additional transformer possible, even if the transverse -, ", -; o-1nn tt-i nht; nr1; rect. As in Fig.1. but directly as shown in Fig. 2.

Are longitudinal and transverse regulation directly with the windings to be regulated connected and also the longitudinal regulation outside the main transformer attached, two additional transformers are required (Fig. 2).

The invention serves the task of the 90o transverse regulation for star or open-switched windings of three-phase transformers compared to the previous ones to simplify common circuits in the possible area of application.

According to the invention, the object is achieved with the arrangement. a step control winding for 90o cross regulation for star and open circuit in three-phase transformers solved.

The arrangement of the step regulating winding is characterized by the following features: 1.) For each phase, it consists of one of the number of steps on the load switch for 90o cross regulation = an adapted number of consecutively series-connected coil groups (G). Each coil group consists of two coils, which are housed on two legs with magnetic fluxes out of phase by 120o and are connected in such a way that UG = voltage of a coil group USp = voltage of a coil The series connection of the coil groups can be done in three different ways. These are shown vectorially in Figs. 3, 4 and 5.

2.) With the coil groups on the legs V and W is for phase U, with the coil groups on the legs W and U is for the phase V and with the coil groups on the legs U and V is 90o for the phase W. phase shifted voltage generated.

Accordingly, the coil groups of the legs V and W are connected to the phase U to be controlled, the coil groups of the legs W and U analogously to the phase V and the coil group to the legs U and V analogously to the phase W , as shown in the circuit diagram in Fig. here for star connection, shows. The series connection of the coil groups in Fig.6 corresponds to the vector connections according to Fig.3 3.) The coil group rows on the Schenki # In UV, VW and.WU are separate windings. This makes it possible that a) the coil group rows can be connected to the windings to be controlled for star or open circuit even without an intermediate circuit (additional transformer); b) the coil group rows can be connected to any point of the windings to be controlled, e.g. to the end of the winding (star point) (Fig.3), to the beginning of the winding (Fig.4) or to the transition of the rows - to the parallel winding of a star economy circuit ( Fig.5).

Two examples in which the invention is applied are shown in FIG Fig.7 and Fig.10. Figs. 8, 9, 11, 12 and 13 are used for explanations.

1st example Fig.7 Circuit of a three-phase transformer @, vector group Yy0 (d) with longitudinal and 90- lateral regulation Fig.S vector diagram for this circuit. Angle of the phase rotation in the transverse regulation Fig.9 Vector connections of the coil groups for the 90 ° transverse regulation according to the invention. z. Example Fig.10: Circuit of an additional regulating three-phase transformer, vector group DIII with longitudinal and transverse regulation Fig.11: Vector diagram for this additional transformer in connection with the voltage vectors of a main transformer. The OB winding of the main transformer is connected in star and connected directly to the control windings of the additional transformer Fig.12 and Fig.13: Two of the possible types of connection of the coil groups for this circuit according to the invention, shown vectorially for phase V. The coil groups for phases U and W are connected in an analogous manner. The advantages that can be achieved with the invention can be seen from the comparisons of Fig.1 to Fig.14 and Fig.2 to Fig.15.

Fig.14: Vector illustration for the circuit of a three-phase transformer according to Fig.7, vector group ly0 (d) with hanging and arrangement of a step regulating winding for_90o lateral regulation.

The Fig.14 shows that with this circuit, in contrast. to the in Fig.1, no additional transformer is required This results in fewer Costs and operating losses are also reduced. Another advantage of this circuit is almost the same short-circuit voltage tendency as that of transformers without Cross regulation.

Fig.15: Vector representation for the example in Fig.10 with main (HT) and additional transformer (ST).

Fig.15 shows that this circuit is in contrast to the circuit According to Fig.2 only one additional transformer is required. The cost becomes substantial and operating losses are also reduced.

The arrangement of the step regulating winding for 90o cross regulation according to Invention, applied to autotransformers, offers similar advantages.

Designations in ::. The figures. .HT = main transformer ZT, ZT1, ZT2 = additional transformers G = _ coil group L = reverser of the load switch for longitudinal regulation Q = reverser of the load switch for transverse regulation R = control range UG = voltage of a coil group Usp = voltage of a coil UZ 'XZ' VZ 'y Z 'WZ' ZZ = connections of the additional transformer uz, vz, wz = connections of the excitation winding of the additional transformer U, V, W, Mp, u, v, w, mp = terminal designations of transformers = angle of phase rotation.

Claims (1)

PATENT CLAIM _ Arrangement of a step regulating winding for 90o-Querm + regulation with star and open circuit in three-phase transformers, characterized in that, separately for each phase, a regulating winding with a number of series-connected coil groups is provided, each of them Coil group consisting of two coils, which are placed on two legs of a three-phase core (or on two single-phase cores of a three-phase bank) with fluxes out of phase by 120 ° and connected in such a way that the coil group voltage is equal to V, x coil voltage, the coil groups pouring onto the leg V and W are housed, with the phase U to be controlled, analogously the coil groups, housed on the legs W and U with phase V and the coil groups, housed on the legs U and V, are connected to phase W. The respective coil group row can be connected to the corresponding phase at the star point, at the input or another winding point (star economy circuit).