JPH0646615B2 - Load tap change transformer with intermediate tap - Google Patents

Abstract

1. Tapped transformer, in which the winding of each phase is split in its centre and each winding part (W1, W2) is provided from this centre outwards with several taps (1 to 3, 4 to 6), which are switchable in and out in sequence by means of a selector switch, to the stationary tap contacts (K1 to K6) - arranged in a circle - of which the taps (1 to 6) are connected and the movable contacts (10) of which are pivotable from tap contact (K1 to K6) to tap contact (K1 to K6) about the center of the circle, characterised thereby, that the selector switch is a load diverter switch, which is operable under load and in which the taps (1, 2, 3 or 6, 5, 4) of both the winding parts (W1, W2) are connected in opposite sequence to the stationary contacts (K1, K2, K3 or K6, K5, K4) and in which the movable contacts (10) are constantly in engagement with an annular lead-out contact (14, 15), wherein the annular lead-out contact is subdivided into two parts (14, 15), the first part (14) of which is associated with the tap contacts (K1, K2, K3) of the first winding part (W1) and the second part (15) of which is associated with the tap contacts (K4, K5, K6) of the second winding part (W2), wherein the first part (14) of the lead-out contact is electrically connected with the last tap (4) - as seen from the centre (M) - of the second winding part (W2), while the second part (15) of the lead-out contact is connected with the first tap (3) - as seen from the centre - of the first winding part (W1), and wherein the movable contacts (10), simultaneously with their change from the tap contact (K3) of the first tap (3) of the first winding part (W1) to the tap contact (K4) of the last tap of the second winding part (W2), change without interruption from the first part (14) to the second part (15) of the lead-out contact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention divides each phase winding into centers and provides each of the divided windings with a plurality of taps starting from the center and is fixed in a ring shape. A load that can connect / disconnect the taps in order by using a tap selector that connects the taps to the tap contactors and the movable contact unit sequentially rotates the tap contacts around the center point of the circle. Time tap switching transformer.

[Conventional technology]

This type of transformer is equipped with an intermediate voltageless tap changer which can only be operated when not normally energized. Therefore, in order to adjust the voltage, it is necessary to stop the power supply to the transformer. With a series of modernization of the power supply network with high power density and complicated wiring, the existing power supply network uses a tap changer transformer under load, that is, a transformer capable of voltage adjustment during load, on a larger scale. There is a need to. Replacing a transformer with a non-voltage tap changer with a transformer that can be adjusted under load is naturally expensive. Therefore, in this type of transformer, efforts are being made to replace existing voltageless tap changers with load tap selectors. For transformers with neutral taps, this procedure is usually not very difficult. However, this is different for transformers with center taps. This is because it is necessary to connect two different taps for each phase to each other. This requires the use of two load tap selectors or one two-pole load tap selector for each phase. This requirement is, of course, very costly and is usually frustrated because the load tap selector cannot be accommodated solely in terms of location.

[Problems of the Invention]

The object of the present invention is therefore to significantly improve the possibility of retrofitting a transformer with an intermediate voltageless tap changer in terms of costs and storage space.

[Means for solving the problem]

According to the present invention, the above-mentioned problem is a load tap switching transformer of the type described at the beginning, wherein the tap selector is a load tap selector that can be operated at the time of load, and both of the split windings W1 and W2 are Taps 1, 2, 3; 6, 5 and 4 are in reverse order to each other. Tap contacts K1, K2, K3; K6, K5
K4, the movable contact unit 10 is always engaged with the ring-shaped lead-out contacts 14, 15 divided into two parts, one of the draw-out contacts 14 is a tap contactor K1 of the first split winding W1. , K2, K3, and the other drawer contact 15
Are attached to the tap contacts K4, K5, K6 of the second split winding W2, respectively, and the lead-out contactor 14 is centered on the last tap 4 of the second split winding W2 and the draw-out contactor 15 as viewed from the center. As seen from the above, each of them is electrically contacted with the first tap 3 of the first split winding W1, and from the tap contactor K3 of the first tap 3 of the first split winding W1 to the last tap 4 of the second split winding W2. This is solved by switching to the tap contactor K4 of No. 1 and at the same time, the movable contact unit 10 switches from one pullout contactor 14 to the other pullout contactor 15 without interruption.

Other advantageous configurations according to the invention are set forth in claim 2.

〔The invention's effect〕

A significant advantage of the present invention is that an improved conventional tap load selector can be utilized to retrofit a tap tap transformer with an intermediate tap. It is no longer necessary to use two load tap selectors for each phase, or one two pole load tap selector. The loadless tap selector can be used in place of the original voltageless tap changer without major modification to the transformer. An add-on load tap selector can also be used.

Claim 2 presents a rational construction of the on-load tap selector to be used.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to the drawings of an embodiment schematically showing a tap change transformer under load according to the present invention.

As can be seen, the voltage regulation transformer has two split windings W
1, W2, and these split windings are provided with three taps 1, 2, 3 and 4, 5, 6 respectively toward the center M. These taps are the fixed tap contacts K1, K2, K3 and K4, K5 of the load tap selector.
Each is connected to K6. The tap contactor K1
The K6 are arranged in a ring shape as usual. The load tap selector includes a movable contact unit 10 that can pivot from one tap contact to an adjacent tap contact about a circle center point. The movable contact unit has one main contact 11, two resistance contacts 12 and one sliding contact 13. The sliding contact 13 is connected to ring-shaped pull-out contacts 14 and 15 which are composed of two parts.
In that case, the main contact 11 is directly connected to the sliding contact 13, but the two resistance contacts 12 are respectively connected to the protective resistance 1
It is connected to the sliding contact 13 via 6. As described above, the ring-shaped lead-out contactor has two parts, and the lead-out contactor 14 that is the first part is attached to the tap contacts K1 to K3 and is separated from the center M of the split winding W2. Connected to tap 4. On the other hand, the extraction contact 15 which is the second component is attached to the tap contacts K4, K5 and K6 and is connected to the tap 3 located at the center M of the first split winding W1.

At the position shown in FIG. 1, the lowest voltage is adjusted. Current flow is from tap 1 to tap contactor K1, main connector 1
1, the sliding contactor 13, and the pull-out contactor 14 to reach the tap 4. All windings between taps 1 and 4 are shorted. To switch to tap 2 with the next highest voltage,
The movable contact unit 10 is moved from the tap contactor K1 to the tap contactor K2. In that case, as is well known, short-time bridging of both tap contacts K1 and K2 takes place, and one resistance contact 12 still contacts the tap contact K1,
The other resistance contact 12 has already reached the tap contact K2 (see also FIG. 2). When the movable contact unit 10 comes to the operating position of the tap contactor K2, as can be easily understood, the winding part between the tap 1 and the tap 2 is energized, and the voltage of the voltage adjusting transformer rises accordingly. To do. When the tap contactor K3 is further switched, the winding portion between the tap 2 and the tap 3 is energized to further increase the voltage.

According to FIG. 2, the movable contact unit 10 switches from the tap contactor K3 to the tap contactor K4. By this switching, the sliding contactor 13 is also switched from the drawer contactor 14 to the drawer contactor 15. If the current flow first reaches the tap 4 from the tap 3 via the tap contactor K3 and the extraction contactor 14,
After the switching is completed, the current flow reaches the tap 4 from the tap 3 via the pull-out contactor 15 and the tap contactor K4. This switching process means that no voltage fluctuations occur in the voltage regulation transformer. In the next switching process, the movable contact unit 10 switches from the tap contactor K4 to the tap contactor K5. Therefore, the winding portion between the taps 4 and 5 is energized to further increase the voltage. Finally, the movable contact unit 10 further reaches the tap contact 6 for adjusting to the highest voltage.

When the movable contact unit 10 is switched from the tap contactor K3 to the tap contactor K4, a part of the current also flows through both the extraction contactors 14 and 15, so that the sliding contactor 1
3 simultaneously switches from the pull-out contactor 14 to the pull-out contactor 15 without current loss. Therefore, the drawer contacts 14, 15
The arc-resistant material is also used for the corresponding end 17 and the end 18 of the sliding contact 13.

In the schematic, all contacts are in the same plane, but it is clear that this situation is not necessary in a practical configuration. For example, the pull-out contacts 14 and 16 can be placed in the plane above or below the tap contacts K1 to K6 fixed in a ring shape, or the movable contact unit can be configured as a rolling bridge contact. it can. The device according to the invention is not necessarily limited to the number of taps shown.

[Brief description of drawings]

Fig. 1, wiring diagram of the transformer in the operating position at tap 1 adjusted to the lowest voltage, Fig. 2, wiring diagram of the transformer during switching from tap 3 to tap 4. Reference numerals in the figure: W1, W2 ... Split winding M ... Winding center K1-K6 ... Fixed contacts 1-6 ... Tap 10 ... Movable contact unit 11 ... Main contact 12 ... Resistance Contact 13 ...... Sliding contact 14,15 ...... Drawer contact 17 ...... End of drawer contact 18 ...... End of slide contact

Claims (2)

[Claims] 1. A winding of each phase is divided at the center, a plurality of taps starting from the center are provided in each of the divided windings, and the tap is connected to a tap contact fixed in a ring shape. The tap selector in a load tap change transformer, in which the movable contact unit can sequentially connect and disconnect the taps by using a tap selector that sequentially rotates the tap contacts around the center point of the circle, It is a load tap selector that can be operated at the time of loading, and taps (1, 2, 3; 6, 5, 4) of both split windings (W1, W2) are respectively tap contacts (K1, K2, K3; K6). K5, K4), and the movable contact unit (10) is always engaged with the ring-shaped drawer contact (14, 15) divided into two parts, and one drawer contact (14) is the first. Split winding (W1) tap contacts (K1, K2, 3) The tap contact (K of the other lead-out contacts (15) of the second divided winding (W2)
4, K5, K6), respectively, and pull-out contacts (1
4) is the last tap (4) of the second split winding (W2) when viewed from the center, and the extraction contact (15) is the first tap (3) of the first split winding (W1) when viewed from the center. ), And the second split winding (W) from the tap contact (K3) of the first tap (3) of the first split winding (W1).
Tap contact (K4) of the last tap (4) of 2)
At the same time when the movable contact unit (10) is switched to the
A tap change transformer under load, which switches without interruption. 2. A drawer contact (1) that is bridged during a switching operation.
4) and both ends (17) of the withdrawal contact (15) and the movable contact unit (10) engaging these ends.
2. A load tap change transformer according to claim 1, characterized in that both ends (18) of the sliding contact (13) are both made of arc-resistant contact material.