Balance-to-unbalance traction-feeding transformer

FIELD: electricity.

SUBSTANCE: balance-to-unbalance traction-feeding transformer includes three-leg core, three-phase symmetric primary winding and three-phase secondary winding. Secondary winding is connected as per three-rayed zigzag scheme, each ray of which consists of two in-series connected similar windings located on different core legs. Each of the windings of one of the rays has voltage which is 2.5-3.0 times less than that of each of the windings in two other rays. Transformer is converter of three-phase voltage into symmetric two-phase one with phase displacement angle between voltage vectors, which is close to 90.

EFFECT: simplifying the design and economy of materials.

1 dwg

 

The invention relates to the field of electrical engineering and can be used in the manufacture of traction transformers for railway electrification on alternating current.

Known traction transformer, containing three magnetic circuit and three-phase symmetrical winding, the primary high-voltage and secondary NN (1). The HV winding is connected to the mains and to the LV winding is connected electric propulsion on the AC. One of the phases of LV winding is attached to the rails and grounded (for example), and the other two phases (for example, a and b) separately connected to the contact wire of the left and right of way. The phase angle between vectors linear voltage winding low voltage equal to sixty degrees.

This scheme electrification even with the same load on two unbalanced line voltage. As the load between the contact wires missing. The asymmetry of the load leads to high current reverse order and unwanted unbalance voltage in the supply network. In addition, the transformer capacity is not fully used.

To eliminate these disadvantages of the proposed balancing traction transformer. Connection diagram phases of HV and LV windings it remains the same, but the phase angle between the two loaded linear stress increased LV winding is moved through ninety degrees, instead of sixty. The increase of the phase angle at the same load left and right of way provides no currents reverse in the supply network.

The proposed transformer contains three magnetic circuit, three-phase symmetrical primary winding of high-voltage and three-phase unbalanced secondary winding LV, which is connected by the three-beam scheme zigzag. Every ray of LV winding consists of two identical windings connected in series. These windings are located on different cores of the magnetic circuit, each of the windings of one of the beams has a voltage of 2.5-3.0 times less than that of each of the windings in the other two beams. This allows you to increase the phase angle between the loaded line voltage LV winding with about sixty to ninety degrees. Such traction transformer becomes Converter symmetrical three-phase voltage in a symmetric two-phase.

The proposed transformer shown in the drawing.

It contains three magnetic circuit 1, three-phase symmetrical primary winding 2, which is intended for inclusion in the mains supply and the secondary winding 3. The secondary winding 3 are collected by the scheme's three-fold zigzag. Each beam consists of two series-connected identical windings located on the s terminals of the magnetic circuit. Each of the windings of one of the beams has a voltage of 2.5-3.0 times less than that of each of the windings in the other two beams. Shortened beam is designed to connect to the rails and ground, and the other two beam designed for connection with the contact wires.

The transformer works as follows. The primary voltage of the winding 2 is transformed into the winding 3. The angle between the vectors loaded line voltage is close to ninety degrees. Under the same load the left and right of ways in the primary winding 2 current reverse sequence is missing, and the supply voltage is not distorted. But when unequal loads of ways he appears, and the supply voltage may be distorted. However, this drawback is inherent to all transformer converters three-phase voltage two-phase (2).

A distinctive feature of the proposed transformer is the lack of current zero-sequence in each of the windings under all possible modes of operation.

The transformer is easy to manufacture and consumption of materials close to transformers General purpose of the same capacity.

Sources of information

1. Three phase three-winding transformer TDTNZH-40000 / 110kV-U. Room 03.03.15-91. The branch directory in electrical engineering, Informalsector, 1991.

2. Ammonds and others who staticheskie electromagnetic frequency converters and the number of phases. SEI, M-L, 1961.

Balancing traction transformer, containing three magnetic circuit, three-phase symmetrical primary winding and three-phase secondary winding, wherein the secondary winding is connected by the three-beam scheme zigzag, each beam which consists of two connected in series the same windings located on different cores of the magnetic circuit, each of the windings of one of the beams has a voltage of 2.5-3.0 times less than that of each of the windings in the other two beams.



 

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