JP5525331B2 - DC power supply - Google Patents

Description

  Embodiments of the present invention relate to a DC power supply apparatus that can reduce energy injected into a DC circuit breaker connected to a DC circuit.

  Conventionally, in a DC circuit such as an electric railway feeder circuit, a DC circuit breaker such as a vacuum circuit breaker or an air circuit breaker is connected to protect the circuit. A reactor is connected to such a DC circuit so as to reduce the rate of change in current at the time of an accident and facilitate interruption (see, for example, Patent Document 1).

  In this type of DC circuit, as shown in FIG. 5, the rectifier 2 is connected to the secondary side of the transformer 1, and DC power is supplied. A DC circuit breaker 3 is connected to the positive polarity side of the rectifier 2, and DC power is supplied to the train 5 via the feeder 4. The rail 6 serving as a return line is connected to the negative polarity side of the rectifier 2.

  On the other hand, the electric power generated when the train 5 uses the regenerative brake is converted into AC power via the inverter 7 and collected. In the DC circuit on the inverter 7 side, a reactor 8 of several mH is connected in series, and a capacitor 9 and a resistor 10 connected in series are connected in parallel to suppress the rate of change of fault current and protect it from overvoltage. Has been done.

JP 2010-45920 A

In the conventional DC circuit described above, when an accident such as a short circuit occurs, an accident current having a current change rate of about 1 MA / s and a peak value of several kA to several tens of kA flows. This accident current is interrupted by the DC circuit breaker 3, but the energy stored in the reactor 8 must also be interrupted at the same time. The energy stored in the reactor 8 is obtained by ½ LI ² , and when a reactor 8 of 5 mH is used, it becomes several hundred kJ.

  As described above, the DC circuit breaker 3 is injected with the sum of the accident current and the energy accumulated in the reactor 8, and there is a problem that the amount of wear of the contacts and the like increases. In addition, the operating force had to be increased in proportion to the energy. For this reason, it was necessary to reduce the energy accumulated in the reactor 8.

  An embodiment of the present invention has been made to solve the above-described problem, and an object thereof is to provide a DC power supply device capable of reducing energy stored in a reactor connected in series to a DC circuit.

In order to achieve the above object, a DC power supply according to an embodiment of the present invention includes a rectifier that supplies power to a DC circuit, a DC circuit breaker that protects a circuit connected in series to the rectifier, and the DC circuit breaker. comprising a reactor to reduce the series-connected current change rate, an inverter for collecting the generated electric power in the DC circuit and an electrical member diverting connected in parallel fault current in the reactor, the electric member , A circuit that closes in synchronization with the opening command of the DC circuit breaker.
And a resistor connected in series to the switch .

The figure explaining the circuit structure of the direct-current power supply device which concerns on Example 1 of this invention. The figure explaining the circuit structure of the DC power supply device which concerns on Example 2 of this invention. The figure explaining the circuit structure of the DC power supply device which concerns on Example 3 of this invention. The characteristic view of the nonlinear resistor used for the direct-current power supply device which concerns on Example 3 of this invention. The figure explaining the circuit structure of the conventional DC power supply device.

  In an embodiment of the present invention, an electric member for reducing energy is connected in parallel to a reactor connected to a DC circuit, and an accident current is shunted to the electric member. Embodiments of the present invention will be described below with reference to the drawings.

  First, a DC power supply apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a diagram illustrating a circuit configuration of a DC power supply device according to Embodiment 1 of the present invention. In FIG. 1, the same components as those in the prior art are denoted by the same reference numerals.

  As shown in FIG. 1, a rectifier 2 is connected to the secondary side of the transformer 1 to supply DC power. The positive polarity side of the rectifier 2 is connected to a vacuum or atmospheric DC breaker 3 that protects the DC circuit, and DC power is supplied to the train 5 via the feeder 4. The rail 6 serving as a return line is connected to the negative polarity side of the rectifier 2.

  On the other hand, the electric power generated when the train 5 uses the regenerative brake is converted into AC power via the inverter 7 and collected. In the DC circuit on the inverter 7 side, a reactor 8 of several mH and a resistor 11 of several Ω connected in parallel are connected in series. The inverter 7 is connected in parallel with a capacitor 9 and a resistor 10 connected in series.

  In such a circuit configuration, for example, if the inductance of the reactor 8 is 5 mH, the resistance value of the resistor 11 is 1Ω, and an accident current having a peak value of 10 kA and a current change rate of 1 MA / s flows, the accident occurs in the reactor 8 and the resistor 11. The current is shunted in a similar manner. For this reason, the energy stored in the reactor 8 is about ¼ when the resistor 11 is not connected. The above-mentioned fault current is a magnitude that can be generated in a general electric railway feeder circuit.

  During normal operation, the rate of change in current is as low as 10 kA / s or less, and most of the current flows through the reactor 8. Therefore, the current flowing through the resistor 11 connected in parallel is very small and it is necessary to consider the influence of heating and the like. Absent. It is preferable that the resistance value of the resistor 11 be equal to or less than the impedance generated in the reactor 8 when the accident current is energized.

  Here, in the event of an accident, the resistance of the reactor 8 increases in proportion to the frequency component of the current, and the accident current is shunted to the resistor 11. Therefore, the resistor 11 is referred to as an electric member that shunts the accident current flowing through the reactor 8. .

  According to the DC power supply device of the first embodiment, since the resistor 11 is connected in parallel to the reactor 8 connected in series with the DC circuit, the accident current is shunted to the reactor 8 and the resistor 11 and accumulated in the reactor 8. Energy can be suppressed, and energy injected when the DC breaker 3 is shut off can be reduced.

  Next, a DC power supply apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2 is a diagram illustrating the circuit configuration of the DC power supply device according to the second embodiment of the present invention. In addition, the point from which Example 2 differs from Example 1 is the member connected to a reactor. In FIG. 2, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 2, a resistor 12 and a switch 13 connected in series are connected in parallel to the reactor 8. The resistance value of the resistor 12 can be made smaller than that of the resistor 11 of the first embodiment. The switch 13 is closed from the open circuit in synchronization with the opening command of the DC circuit breaker 3.

  Thereby, at the time of interruption | blocking, the switch 13 is closed and an accident electric current can be shunted to the resistance 12. That is, since the opening command is issued to the DC circuit breaker 3 before the accident current starts flowing and reaches the peak value, the current flowing through the reactor 8 can be reduced.

  Here, the resistor 12 and the switch 13 are referred to as electric members that shunt the accident current flowing through the reactor 8.

  According to the DC power supply device of the second embodiment, the switch 13 is closed in synchronization with the opening command of the DC circuit breaker 3, and the accident current is shunted. Therefore, the energy accumulated in the reactor 8 can be reduced. .

  Next, a DC power supply according to Embodiment 3 of the present invention will be described with reference to FIGS. FIG. 3 is a diagram illustrating a circuit configuration of a DC power supply device according to Embodiment 3 of the present invention, and FIG. 4 is a characteristic diagram of a nonlinear resistor used in the DC power supply device according to Embodiment 3 of the present invention. The third embodiment is different from the first embodiment in the member connected to the reactor. In each figure, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, a non-linear resistor 14 such as a zinc oxide element is connected to the reactor 8 in parallel. In addition, when the zinc oxide element single-piece | unit is connected in series and it is set as the nonlinear resistor 14, the voltage V1 between terminals mentioned later can be controlled finely.

  The inter-terminal voltage V1 of the nonlinear resistor 14 is set by a voltage generated when an accident current flows through the reactor 8, as shown in FIG. That is, assuming that the inductance of the reactor 8 is, for example, 5 mH, the peak value of the accident current is 10 kA, and the current change rate is 1 MA / s, the terminal voltage V1 at which the resistance value suddenly changes and decreases is 5000 V. The inter-terminal voltage V1 is set to be equal to or lower than the withstand voltage value of an electric device such as the rectifier 2 connected to the DC circuit. The resistance value during normal operation is a high resistance of 1000Ω or more.

  Here, the non-linear resistor 14 is referred to as an electric member that diverts an accident current flowing through the reactor 8.

  According to the DC power supply device of the third embodiment, when the accident current is energized, the nonlinear resistor 14 has a low resistance and diverts the accident current. Therefore, the energy accumulated in the reactor 8 can be reduced.

DESCRIPTION OF SYMBOLS 1 Transformer 2 Rectifier 3 DC circuit breaker 4 Feed line 5 Train 6 Rail 7 Inverter 8 Reactor 9 Capacitor 10, 11, 12 Resistance 13 Switch 14 Nonlinear resistance body

Claims (1)

A rectifier for supplying power to the DC circuit;
A DC circuit breaker for protecting a circuit connected in series to the rectifier;
A reactor for reducing the rate of change in current connected in series to the DC circuit breaker;
An inverter that recovers the electric power generated in the DC circuit;
An electric member for shunting an accident current connected in parallel to the reactor ,
The electrical member is a switch that closes in synchronization with an opening command of the DC breaker;
A DC power supply device comprising a resistor connected in series to the switch.

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