JP6011602B2 - AC feeder system - Google Patents

Description

  The present invention relates to an AC power feeding system, and more particularly to a power source switching system for an electric vehicle to pass through different power source sections having substantially the same phase.

  Since AC electric vehicles such as the Shinkansen are single-phase, they receive AC power from an electric power company in three phases and feed the AC electric vehicle using a three-phase to single-phase converter. As this three-phase to single-phase converter, a Scott transformer that obtains two single-phase power supplies (M and T) on the secondary side, and two single-phase power supplies (A and B) on the secondary side There are wood bridge transformers etc. to get.

  For this reason, the vehicle travels across power sources having different phases, and a section for matching different power sources is provided immediately below the substation in order to prevent a short circuit in the different phases. In conventional lines, a dead section is provided at the location where the different power sources are matched, and in the Shinkansen, a middle section is provided as a switching section to switch the power source.

  In addition, at the feeding section, power supplies with almost the same phase are matched, but there is a voltage difference depending on the presence status of the vehicle, and there is a slight phase difference, so it is necessary to always classify, The switching method is the same as for substations.

  Japanese Patent Application Laid-Open No. H10-228707 describes a tap switching transformer for switching the phase of a power source without causing an instantaneous power failure in the middle section.

Japanese Patent Application No. 2014-131079

  However, since Patent Document 1 is mainly applied to substations whose phases are different by 90 °, in order to apply the equipment of Patent Document 1 to a power distribution station where power supplies having substantially the same phase are matched, Switching and control switching are necessary, which increases the burden in terms of equipment and cost.

  As described above, in the middle section of a power distribution section where power sources that generate a voltage difference with substantially the same phase are matched, it is a problem to reduce the cost and supply power without an instantaneous power failure. .

  The present invention has been devised in view of the above-described conventional problems, and one aspect thereof is substantially the same as that output from the first three-phase to single-phase conversion transformer and the second three-phase to single-phase conversion transformer. An AC feeding system in which a middle section of a feeding section having an inlet air section and an outlet air section at both ends is provided at a butt of a phase power supply, wherein the middle section of the feeding section is A first isolation transformer that steps down the voltage output from the first three-phase to single-phase conversion transformer, and connected in parallel with the first isolation transformer, and output from the second three-phase to single-phase conversion transformer A second insulation transformer that steps down the voltage; a step-up transformer that steps up the voltage stepped down by the first insulation transformer and the second insulation transformer and outputs the boosted voltage to a middle section; and the secondary winding of the first insulation transformer And the primary winding of the step-up transformer A first switch interposed between the first insulation transformer, a second switch interposed between the secondary winding of the second insulation transformer and the primary winding of the step-up transformer, and the first insulation transformer A first reactor inserted between a secondary winding and the first switch, and a second reactor inserted between a secondary winding of the second insulation transformer and the second switch Until all the pantographs of the electric vehicle pass through the inlet side air section, the first switch is turned on and the second switch is turned off, and all the pantographs of the electric vehicle are turned on the inlet side After passing through the air section, the second switch is turned on with the first switch turned on, and then the first switch is turned off. After all the pantographs of the electric vehicle have passed through the outlet side air section , Turn off the second switch and turn off the first switch. Characterized by a.

  As one aspect thereof, the first switch and the second switch are thyristor switches.

  According to the present invention, it is possible to reduce the cost and supply power without causing an instantaneous power failure in the middle section of the feeder section where a voltage difference occurs in substantially the same phase.

Schematic which shows the alternating current feeding system in embodiment. Schematic which shows the three phase-single phase conversion transformer in embodiment. Schematic which shows the middle section of the feeding section in embodiment.

  The present invention proposes a new AC feeding system that supplies power without an instantaneous power failure in the middle section of the feeding section where the power supplies of substantially the same phase are matched.

  Hereinafter, an embodiment of an AC feeding system according to the present invention will be described in detail with reference to FIGS.

[Embodiment]
FIG. 1 is a schematic diagram showing an AC feeding system according to the present embodiment. As shown in FIG. 1, the AC feeding system in the present embodiment includes first and second three-phase / single-phase conversion transformers 2a and 2b, and first and second three-phase / single-phase conversion transformers 2a, Middle section 4a, 4b, 4c, 4d of the substation where the voltages of different phases of 2b are matched, and the distribution section where the voltages of almost the same phase of the first and second three-phase / single-phase conversion transformers 2a, 2b are matched Middle sections 4e and 4f, and first and second three-phase / single-phase conversion transformers 2a and 2b, and circuit breakers 3a to 3h provided between the middle sections 4a to 4f.

  FIG. 2 is a schematic diagram showing the first and second three-phase / single-phase conversion transformers 2a and 2b in the present embodiment. In FIG. 2, a Scott transformer is shown as an example of the first and second three-phase / single-phase conversion transformers 2a and 2b. As shown in FIG. 2, there are an M seat and a T seat on the secondary side of the Scott transformer 2a, and the phases of the M seat and the T seat are different by 90 °. A trolley line T and a feeder line F are drawn from the secondary side M seat and T seat, respectively.

  As shown in FIG. 1, the T section trolley wire T and the M seat trolley wire T are abutted in the middle sections 4a, 4b, 4c, and 4d of the substation. The middle section in which the power sources of the T-seat and M-seat with different phases are matched is not directly related to the present invention, and thus description thereof is omitted here.

  The middle sections 4e and 4f in the feeding section are matched with the voltages of substantially the same phase at the T seat of the first three-phase / single-phase conversion transformer 2a and the T seat of the second three-phase / single-phase conversion transformer 2b. ing.

  FIG. 3 is a schematic explanatory view showing a middle section of the feeding section where the power supply of the T seat and the T seat are abutted. Although FIG. 3 shows a power distribution section where the power supply of the T seat and the T seat are abutted, the power distribution section where the power supply of the M seat and the M seat is abutted is the same.

  As shown in FIG. 3, in the middle sections 4e and 4f of the feeding section, the T-seat trolley wire T and the feeder wire F drawn from the secondary winding of the first three-phase / single-phase conversion transformer 2a The primary winding of the first insulation transformer AT1 is connected to the end. The primary winding of the second insulation transformer AT2 is connected to the ends of the T-seat trolley wire T and the feeder wire F drawn from the secondary winding of the second three-phase / single-phase conversion transformer 2b. The The first and second insulation transformers AT1 and AT2 are each provided with a secondary winding, and the first and second insulation transformers AT1 and AT2 step down the voltage from about 30000V to about 6000V, for example. .

  Reactors L1 and L2 are connected to one ends of the secondary windings of the first and second insulation transformers AT1 and AT2, respectively. The other ends of the reactors L1 and L2 are respectively connected to one ends of first and second switches (in this embodiment, thyristor switches: hereinafter referred to as thyristor switches) S1 and S2, and the first and second thyristors. The other ends of the switches S1 and S2 are connected. The other ends of the secondary windings of the first and second insulating transformers AT1 and AT2 are connected to each other.

  One end of a primary winding of a step-up transformer TR (for example, an autotransformer) is connected to a common connection point of the first and second thyristor switches S1 and S2, and the other ends of the first and second isolation transformers AT1 and AT2 are connected to each other. The other end of the primary winding of the step-up transformer TR is connected to the common connection point.

  One end of the secondary winding of the step-up transformer TR is connected to the trolley line T, and the other end of the secondary winding of the step-up transformer TR is connected to the rail line R. For example, the voltage of about 6000 V is boosted to about 30000 V by the step-up transformer TR. First and second air sections D1 and D2 (generally about 50 m) are provided at both ends of the middle section (generally about 1000 m) of the trolley wire T.

  Although the left T seat and the right T seat in FIG. 3 are basically substantially in phase, a voltage difference (about 2000 V to 3000 V) is generated depending on the presence state of the electric vehicle 1.

  Therefore, in the case of the conventional AC power feeding system, when the electric vehicle 1 passes through the electric power 1 with power running between them, an arc is generated due to a short circuit between both seats in the pantograph. Repeating this situation is unacceptable for an AC feeder system, so it is necessary to have the same phase and voltage when the pantograph passes through the middle section of the feeder section.

  The operation of the first and second thyristor switches S1 and S2 in the AC feeding system of this embodiment will be described. In the present embodiment, it is assumed that there is means (for example, a track circuit) that detects that the electric vehicle 1 has entered and passed through the middle section.

  First, the first thyristor switch S1 is turned on and the second thyristor switch S2 is turned off until the electric vehicle 1 enters the middle section.

  When all the pantographs of the electric vehicle 1 pass through the first air section D1, the second thyristor switch S2 is turned on while the first thyristor switch S1 is kept on. Thereafter, the first thyristor switch S1 is turned off. That is, there is a time when both the first and second thyristor switches S1 and S2 are turned on. Here, the time during which both the first and second thyristor switches S1 and S2 are ON is preferably as short as possible in consideration of the time during which a blackout current can flow while avoiding an instantaneous power failure. In this embodiment, the time from when the second thyristor switch S2 is turned on to when the first thyristor switch S1 is turned off (that is, the time when both the thyristor switches S1 and S2 are turned on) is several ms to several tens of times. ms.

  Thereafter, after the electric vehicle 1 passes through the second air section D2, the second thyristor switch S2 is turned off, the first thyristor switch S1 is turned on, and the operation waits until the next electric vehicle 1 enters the middle section.

  As described above, according to the AC power feeding system in the present embodiment, the first and second thyristor switches S1 and S2 are instantaneously turned on in a state where the electric vehicle 1 is completely in the middle section. It becomes possible to suppress an instantaneous power failure of the electric vehicle 1 when passing through the middle section. Further, by suppressing the instantaneous power failure of the electric vehicle 1 when passing through the middle section, the instantaneous power failure countermeasure system when passing through the middle section of the vehicle becomes unnecessary.

  In addition, when both the first and second thyristor switches S1 and S2 are instantaneously turned on, the pantograph of the electric vehicle 1 can pass through the middle section without any phase difference and voltage difference. Therefore, the acceleration change when passing through the middle section is eliminated, and the ride comfort is improved. In addition, measures to improve riding comfort are not required.

  When there is a phase difference between the voltage input to the first isolation transformer AT1 and the voltage input to the second isolation transformer AT2, or when the voltage difference is large, the first and second thyristor switches S1 and S2 are switched instantaneously. If the ON state is turned on, a large enveloping current may be generated. In the present embodiment, the first and second reactors L1 and L2 are provided between the first and second thyristor switches S1 and S2 and the secondary windings of the first and second insulation transformers AT1 and AT2, respectively. It is possible to suppress the entangling current generated by instantaneously turning on both the first and second thyristor switches S1 and S2.

  Further, since the primary winding side and the secondary winding side are insulated by the first and second insulating transformers AT1 and AT2, the first three-phase-single-phase conversion transformer 2a and the second three-phase-single It becomes possible to prevent the circulating current flowing between the phase conversion transformers 2b.

  Further, since the voltage is stepped down by the first and second isolation transformers AT1 and AT2, the withstand voltage of the first and second thyristor switches S1 and S2 is lowered (the number of series of the first and second thyristor switches S1 and S2 is reduced). can do.

Moreover, since the excessive inrush current due to the opening and closing of the first and second thyristor switches S1 and S2 is suppressed by the first and second reactors L1 and L2, no inrush current countermeasure devices such as in-vehicle devices are required. In addition, since the inrush current is suppressed, it is possible to simplify the feeder protection system. It is also possible to apply a switching breaker using VCB or the like to the first and second switches S1, S2. In the Tokaido Shinkansen, etc. with a large number of trains, it is necessary to replace the first and second switches S1 and S2 between 1.5 and 2 years, which causes an increase in cost. On routes with a large number of trains, the replacement frequency is reduced and the cost can be reduced by applying thyristor switches S1 and S2 as the first and second switches S1 and S2 as in this embodiment. Become.

  In addition, the single-circuit accident between the poles in the switching breaker system is eliminated, and the reliability of the system is improved.

  In addition, as in Patent Document 1, it is possible to reduce costs compared to a phase conversion device using a tap switching transformer.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

  For example, FIG. 2 shows a Scott transformer, but other three-phase to single-phase converters may be used.

DESCRIPTION OF SYMBOLS 1 ... Electric vehicle 2a, 2b ... Three phase-single phase conversion transformer (Scott transformer)
3a to 3h ... circuit breaker 4a to 4d ... middle section of substation 4e, 4f ... feeder section AT1, AT2 ... first and second insulation transformers (autotransformer)
L1, L2 ... 1st, 2nd reactor S1, S2 ... 1st, 2nd switch (thyristor switch)
TR: Step-up transformer D1, D2: First and second air sections

Claims (2)

Feeder having an inlet side air section and an outlet side air section at both ends at the abutting point of the substantially same phase power source output from the first three phase-single phase conversion transformer and the second three phase-single phase conversion transformer An AC feeder system with a middle section of the division,
The middle section of the feeder section is
A first isolation transformer that steps down the voltage output from the first three-phase to single-phase conversion transformer;
A second insulation transformer connected in parallel with the first insulation transformer and stepping down the voltage output from the second three-phase to single-phase conversion transformer;
A step-up transformer that steps up the voltage stepped down by the first insulation transformer and the second insulation transformer and outputs the boosted voltage to a middle section;
A first switch interposed between a secondary winding of the first insulation transformer and a primary winding of the step-up transformer;
A second switch interposed between the secondary winding of the second insulation transformer and the primary winding of the step-up transformer;
A first reactor interposed between the secondary winding of the first insulation transformer and the first switch;
A second reactor interposed between the secondary winding of the second insulation transformer and the second switch;
With
Until all the pantographs of the electric vehicle pass through the inlet side air section, the first switch is turned on, the second switch is turned off,
After all pantographs of the electric vehicle have passed through the inlet side air section, the second switch is turned on while the first switch is turned on, and then the first switch is turned off.
An AC feeding system, wherein after all the pantographs of an electric vehicle have passed through the outlet side air section, the second switch is turned off and the first switch is turned on.   2. The AC feeding system according to claim 1, wherein the first switch and the second switch are thyristor switches.

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