JPS6339425A - Method and apparatus for controlling parallel operation of multistage transformer by main and subsidiary systems - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is described in detail in the 1-position ζM<min of claim 1. The present invention relates to a method and apparatus for controlling the 11ζ train operation of a two-stage or multi-stage transformer.

The method of controlling multi-stage transformers in parallel can be executed as is if the transformers have exactly the same data. To do so, it is sufficient in principle for the transformer to be adjusted to the same tap position each time. However, if you try to operate transformers with different numbers of turns between taps in parallel, Δ
has its drawbacks. On the other hand, for parallel operation, it is necessary to minimize the voltage difference during no-load.

The object of the invention is to provide a method for operating transformers with two or more stages in parallel, which can also be used in particular in the case of transformers with different numbers of turns between the taps.

This problem is solved by following the method steps given in claim 1 of the invention. A device suitable for carrying out this method is given in claim 2 above.

An advantage of the present invention is that the no-load voltage of transformers operating in parallel can be easily adjusted. In that case, at each point in time, the transformer in question enters a respective function or performs a slave function. This can be achieved simply by adjusting the designated switching means according to the purpose. n
The switching means q are generally implemented as electronic switching means, but these switching means can of course also be implemented as a switch with purely mechanical operation. This method allows the above operations to be carried out whether the data to be transmitted is in the form of digital values or analog values, for example in the segmented measurement current - in the milliampere range.

The present invention will be explained in detail below with reference to the drawings. As is clear from FIGS. 1 and 2, in the case of the main function of the transformer, switches SO and 81 are closed, but switches S2 and 83 are open.

On the other hand, in the slave function, switches S2 and 83 are closed, but switches SO and 81 are open.

From here, the following functional sequence occurs: For example, the control line C1 is introduced from the voltage stabilizer, via the closed switch SO and another control line C2, the tap changer OT+ of the mains/transformer. The motor drive MA of , receives the tap change command. This main/transformer tap changer OTL
The motor drive MA transmits the current tap position to the encoding unit AI via a transmission line C3. The identification value belonging to that code is applied to the data bus conductor B via the switch Sl.

This data bus conductor B is connected to other transformers operating in slave function.

In the case of slave function, switches S2 and 83 are closed,
When switches SO and SL are open, the following sequence occurs: the tap position of the slave transformer is changed to tap changer OT1. is transmitted from the corresponding motor drive MA to the associated encoding unit AI via the transmission line C3. The voltage range corresponding to this tap is transmitted via intermediate conductor C4 to comparison unit A2 of the slave transformer. The identification value present on the data bus conductor of the voltage tap of the main transformer flows into this comparison unit A2 via the closed switch S2.

When it is confirmed in this comparison unit A2 that the identified value is outside the voltage range of the voltage tap of the secondary transformer,
The motor drive MA of the tap changer of the slave transformer receives the command for changing the tap position via the closing switch S3 and the control line C2.

This command exists until a voltage region appears on the slave transformer that eliminates the identification value of the main transformer.

FIG. 3 shows this relationship. The voltage UL at no-load is given to the first scale, and the sign value of this voltage, for example, the value as an 8-bit value, is again mapped to the 1] scale on the right. On the scale Tri, the first transformer has taps 1 to 6; on the scale T r 2, the second transformer has taps -3 to +3; and on the scale T r 3, the third transformer has taps 1 to 5. The identification value of the transformer is determined by the voltage range. Assume that transformer Trl is in main function and is on tap 2, while slave transformer Tr2 is on tap -2 and slave transformer Tr3 is on tap l.

Identification value LJ I, -5 belonging to tap 2 of transformer Tri
8 corresponds to the identification value of tap-2 of transformer Tr2, and this transformer is in the voltage range of this tap. Instant transformer T
r2 is already in the normal position. The situation is different for transformer Tr3. Identification value U of main/transformer '1' rl
L = 5, 8 is outside the voltage range of tap 1 of slave transformer Tr3. This transformer receives commands to change the tap position as previously described.

This transformer must occupy tap 2, as is clear from FIG. Furthermore, in this example the area for parallel operation of the three transformers extends from the lowest and highest discrimination values of the main transformer, LIL=5,7, to UL=6.2.

As is clear, the manner shown in FIG. 1 can be used for individual control at any time. Open switches S1, S2,
With S3, the above-mentioned functions are deactivated and the control of the transformer takes place only by means of the control line CI and the closing switch SO.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of a transformer unit, and FIG. 2 is a table showing the open/close states of individual switching sections. FIG. 3 is a code list of some multi-stage transformers. Codes used in the figure: 5O9S1, S2. S3...Switch MA...Motor drive section

Claims (1)

[Claims] 1) Each multi-stage transformer is provided with a motor drive section that has a tap position display function and can be controlled by an automatic control section, and the automatic control section of the motor drive section can be individually connected or disconnected, and the main In a method for controlling the parallel operation of two or more stage multi-stage transformers with equal or unequal taps by a secondary method, a) the data of all possible taps of each transformer (Tr1, Tr2, Tr3) are Each transformer encoding unit (A1) is converted into a code value, both as an identification value for each tap and as a voltage range, b) by connecting the control conductors (C1) individually, and converting the transformer into a main/functional (e.g. Tr 1); c) checking the code value corresponding to the current tap of each transformer by means of the signal entering the encoding unit (A1) indicating the tap position of the associated motor drive (MA); d) the sign value of the voltage range of the current tap of each transformer is transmitted to the comparison unit (A2) of that transformer; e) the sign value (of the tap) corresponding to the current tap of the main transformer; (identification value) to the data bus conductor (B) common to all transformers, f) the sign value of the main transformer applied to the data bus conductor (B) to each comparison unit (A )
g) Compare the sign value received from the data bus conductor in a comparator unit (A2) with the value in said unit (A2) of the voltage range of the associated transformer; h) the sign value of the slave transformer A method for controlling the parallel operation of a multi-stage transformer, characterized in that the attached motor drive receives a control command to change the tap as long as it is outside the voltage range to be compared. 2) The tap position indication signal of each motor drive (MA) of each multi-stage transformer is processed by a programmed encoding unit (A
1), and this encoding unit (A1) connects the voltage range corresponding to each tap on this unit side to the comparison unit (A2), and the encoding unit (A1) connects the voltage range corresponding to each tap on this unit side The code value (tap identification value) belonging to the data bus conductor (B) can be connected to the data bus conductor (B) by the first opening/closing part (S1).
B) can be connected to a respective comparator unit (A2) of each transformer by each of the second switching sections (S2), such that the output of each comparison stage of each transformer is respectively connected to the third switching section (S2).
Control conductor (C2) for motor drive attached by S3)
In the case of a main transformer, the control conductors (C1) are connected individually (S0), the first switch (S1) is closed, and the second and third switch (S1) are closed. S2 and S3)
is open, while in the case of a slave transformer, the control conductor (C
1) are individually shut off (S0), and the first opening/closing section (S0) is individually shut off (S0).
1) is open, and the second and third opening/closing parts (S2 and S3) are closed.