Method of balancing of traction-feeding transformer load

FIELD: electricity.

SUBSTANCE: substance of method consists in distribution of highest load of lagging or leading phases of contact network at non-loaded phase of traction-feeding transformer. At that the highest capacity of one of phases of contact network is identified, voltage picked up from non-loaded phase of traction-feeding transformer is rectified and converted with the help of inverter driven by according phase of contact network, and step-up transformer into sinusoid voltage with frequency equal to frequency of the main harmonic of network, and specified voltage is supplied to according phase of contact network. Loading of non-loaded phase of traction-feeding transformer is carried out via rectifier and inverter, only at one phase of contact network, which makes it possible to transfer electric capacity to that phase of contact network, in which unit of contact network capacities comparison has identified the highest capacity.

EFFECT: increased efficiency of using capacity of traction-feeding transformer, reduced volumes of distortion capacity generation in the form of active power by reverse sequence and active power by high harmonics.

2 dwg

 

The invention relates to electric power and is intended for use in power supply systems electrical transport and, in particular, at traction substations AC, as well as for balancing transformers for General use.

Known way to turn the traction transformers, which consists in distributing the load of the contact system in two-phase traction transformer windings are connected respectively to advanced and lagging phases of the network (see Kguard. The supply of electrified Railways. M.: Transport, 1982, p.23-25).

The main disadvantage of this method is unbalanced mode of operation of the traction transformer, as one phase on the side of the traction winding is unloaded, and the other two loaded unevenly respectively load advanced and lagging phases of the contact network. Thus, it can be used only 66.6% of the traction power transformer. In this mode of operation, the traction substation increase the amount of generation of active energy in reverse order and active energy of higher harmonics, which leads to deterioration of the quality of electric energy and the underestimation of power in the point of common connection.

The technical result of the proposed method is to increase efficiency the efficiency of use of the traction power transformer, as well as the decrease in power generation distortions in the form of active power in reverse order and active power in the higher harmonics.

This is achieved by a method for balancing load of the traction transformer, which consists in distributing the load of the contact system in two phases transformer, pre-measure the load on the phases of the contact network and the largest load of one of the phases of the contact network distribute advanced to third, unloaded, phase transformer, the voltage taken from this phase, rectify and convert using the inverter, the slave network the phase of the contact network, in which the load more in a sinusoidal voltage with a frequency equal to the frequency of the main harmonic, and through single-phase transformer serves the specified voltage in the phase of the contact network, where the load more.

The method consists in distributing the load backward or advanced phases of the contact system in the unloaded phase traction transformer, thus determine the largest power of one of the phases of the contact network, the voltage taken from the unloaded phase traction transformer, rectify and convert using inverter slave appropriate phase of the contact network, and the step-up transformer into a sinusoidal voltage with frequency, equal to the frequency of the main harmonic of the network, and serves the specified voltage to the corresponding phase of the contact network. Download the unloaded phase traction transformer through the rectifier and the inverter in a single phase circuit, which allows to transmit electric power to the phase of the contact network, in which the block comparison of the capacities of the contact network has identified the most power.

Figure 1 is a diagram of a device that implements the inventive method; figure 2 - diagram of the simulation of this method.

Figure 1: 1, 2, 3 is unloaded, the backward and forward phase traction transformer; 4 - rail; 5 - step-down transformer unloaded phase traction transformer; 6 - rectifier; 7 - inverter; 8 - up transformer; 9, 10 - vacuum switches on the left and right shoulders of the contact network; 11, 12 - the current transformers on the left and right shoulders of the contact network; 13, 14 - voltage transformers on the left and right shoulders of the contact network; 15, 16 - the power meters in the left and right shoulders of the contact network; 17 - comparison circuit capacity in the contact network; 18 - control circuit switches vacuum switches.

The method is as follows.

After you turn the traction transformer with an unloaded phase 1 to the input of a step-down transformer 5 is supplied to the custody, which is fed to the rectifier 6, the rectified voltage is transmitted to the input of the inverter 7, the slave of the corresponding phase of the contact network, which is increased by means of the transformer 8. Power in the contact network are determined by the power meter 15, 16 in the left and right shoulders of the network, the values of which are fed to the block 17 comparison of capacities, which, by comparing the measured values of power, sends a signal to the circuit 18 controls the switching of vacuum circuit breakers, resulting activated the corresponding vacuum circuit breaker 9, 10 on the left and right shoulders of the contact network; AC sinusoidal voltage with a frequency equal to the fundamental frequency harmonics from the output of the inverter 7, the slave network via the single-phase transformer 8, is supplied to the corresponding phase of the contact network and rail canvas 4.

The inventive method provides a more uniform load distribution in the contact network on the three phases of the traction transformer and thereby the compensation due to straightening and subsequent inverting the unloaded phase traction transformer in an alternating sinusoidal voltage with a frequency equal to the frequency of the main harmonic of the supply voltage and supply it to the corresponding phase of the contact network, as well as reducing the level of higher harmonics due to their vypra the population, and their energy with the help of the inverter will be supplied in the contact network in the form of energy the main harmonics and used for traction.

The modeling method was carried out according to the scheme of figure 2, where: 19, 21, 20 respectively loaded and unloaded phase transformers; 22, 23 - rheostats loads; 24 - single-phase rectifier 25 - inverter driven network; 26, 27 - switches; 28 - clamp meter for measuring phase currents; 29 - ends for measuring phase voltages; 30 - grounding; 31 - CPI "OMSK-M".

When the ratio of output load 5:1, which is given by the rheostats 22,23, the analyzer of the quality of electrical energy 31 gave the following values: the asymmetry coefficient of the voltage in the reverse order of 5.8%, and then through switch 26 to the load 22 connected to the inverter 25, the slave network, which provided a supply of electric power to the load 22 from the unloaded phase 20 by successive rectification by the rectifier 24 and converting DC to AC sine wave voltage of industrial frequency inverter 25, the slave network, and the asymmetry factor of the voltage in a reverse sequence decreased to 0.9%, and the ratio between the capacities of all three phases was 2.5:2,9:1, respectively.

The inventive method eliminates the major disadvantages inherent in the world is this way, because of symmetrical three phase traction transformer. This is mainly what determines which of the two loaded phase traction transformer maximum load, and some of this load is transmitted to the third light phase traction transformer. And, as a consequence, the mode of operation of the traction transformer becomes symmetric, while improving this indicator of the quality of electric energy, as the asymmetry coefficient in a reverse sequence, and also increases the reliability of the traction transformer. Significantly reduced generation of active power in reverse order and active power in the higher harmonics.

The method of balancing the load of the traction transformer, which consists in distributing the load of the contact system in two phases of the transformer, wherein the pre-measure the load on the phases of the contact network and the largest load of one of the phases of the contact network allocates an additional third, the unloaded phase of the transformer, the voltage taken from this phase, rectify and convert using the inverter, the slave network the phase of the contact network, in which the load more in a sinusoidal voltage with a frequency equal to the frequency of the main harmonic, and through single-phase t is Informator serves the specified voltage in the phase of the contact network, where the load is greater.



 

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