Actuation method of transformer of traction substation

FIELD: electricity.

SUBSTANCE: substation transformer start-up method, at which, first, two input terminals are connected to two phases of a three-phase network at transition of phase voltage of the third phase of the network through zero, and then, the third input terminal is connected to the third phase of the network at transition of linear voltage from two previous phases through zero.

EFFECT: simpler implementation of the method and elimination of additional losses in a three-phase transformer owing to providing accuracy of initial moment of actuation of two phases.

2 dwg

 

The invention relates to electrical engineering, in particular to systems for industrial, municipal and traction power supply, and can be used in transformer substations, including for railway and urban (trams, trolley buses, escalators) electrified transport.

The known method include three-phase substation transformer on the AC No. 639120 the USSR, published 25.12.1978 in bull. No. 47, which is used as a prototype. According to the method of connecting two phases of the primary winding of the transformer at the time of maximum voltage between them, and then connect the third phase in the transition of the above-mentioned voltage through zero.

The disadvantage of the prototype method is the complexity of the implementation, due to the fact that the maximum voltage between two phases is difficult, especially when the distortion voltage. Modern consumers in industrial and traction power supply, having a highly variable, reactive, non-linear (including valve) character, create input and output transformer substation distortion of currents and voltages. When the distortion voltage having a random character, may be offset or ambiguity extremum, which makes it difficult to control the maximum voltage.

This feature violates accuracy is ü the inclusion of the two phases in the π/2 line voltage and will not provide for the inclusion without surge current, will increase during the transition process. While the subsequent inclusion of the third phase even at the right time (when switching the above-mentioned voltage through zero) will create a new perturbation to the unfinished transition process.

All this does not completely limit the starting current and the duration of the transition process, creating electrical losses, and one-sided bias of the transformer core will increase the magnetic losses.

The objective of the invention is to simplify the implementation of the method and the elimination of additional losses in three-phase transformer by ensuring the accuracy of the initial inclusion of the two phases.

The solution of the task will be simplified implementation of the method and achieved the exact identification of the moment of inclusion in the π/2 line voltage from these two phases. Ease of implementation is to identify the transition phase voltage of the third phase through zero, using nonorgan, for example, a comparator, one input of which is connected to zero. In addition will be completely eliminated additional trigger losses in the transformer.

The solution of this problem is achieved by the fact that the inclusion of the two input terminals to the two phases of three-phase network are produced in the moment of transition of the phase voltage of the third phase of the network through zero.

usnot the proposed method is illustrated in the following description and the accompanying drawings. In Fig. 1 shows a distorted voltages and currents, and when enabled by a known method, and Fig. 2 - distorted voltages and currents and in the inclusion of the proposed method.

Numerical experiments in MatLab found that the accuracy of the inclusion by a known method violated ambiguous extremum voltage, distorted the 5th and 7th harmonics, and the inclusion of the two phases according to the first maximum linear voltage causes a transition currents (Fig. 1), the attenuation of which lasts several tens of periods. The application of this process include the third phase even at a given point in time during the transition line voltage through zero does not eliminate, but rather exacerbates the situation from the steps of the transition process, i.e. not achieved the desired result. In comparison with this, when turning on the other two phases at the time of zero crossing of the phase voltage of the third phase (Fig. 2), almost immediately achieved steady state currents.

Suitable applications are transformer substation systems for municipal, agricultural, industrial power supply and traction power supply systems electric transport.

The method of inclusion of the substation transformer to the input terminals intended for connection to three-phase with the ti and output terminals, intended for connection through traction network to electrificadora transport, first connect the two input clamp into two phases of three-phase network, and then make the connection to the third input of the clamp to the third phase of the network at the moment of transition line voltage from the two previous phases through zero, characterized in that the inclusion of the two input terminals to the two phases of three-phase network are produced in the moment of transition of the phase voltage of the third phase of the network through zero.



 

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1 dwg, 1 ap

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