JPS63974B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transient surge voltage protection device for a distribution line signal injection device in a distribution line carrying system.

Configuration of Conventional Example and its Problems The conventional example will be described below with reference to FIG. 1 of the drawings. A low voltage capacitor 2 connected to the primary side of the two-winding coupled reactor 1, a primary side circuit that resonates at a frequency higher than the signal frequency due to the reactor 3, a high voltage capacitor 4 connected to the secondary side of the reactor, and an injection impedance 5. , the secondary side circuit that resonates with the signal frequency is a two-winding coupling reactor 1
A coupling circuit is constructed by the mutual conductance of . Further, a series inverter is configured by a DC power supply 6, first and second thyristors 7, 8, and first and second diodes 9, 10, and the coupling circuit has primary and secondary frequency characteristics, Since the impedance always shows a leading phase angle with respect to the signal frequency, it also serves as a commutation circuit for the series inverter. In this distribution line signal injection device,
When the first switch 11 is turned on, the current shown in FIG. 2 and FIG. Due to the transient surge voltage, it is charged to about twice the steady state value, and its value reaches 1000V.

Therefore, even if an attempt is made to cause the distribution line signal injection device to oscillate by turning on the second switch 12, the overcurrent relay 13 for protecting the series inverter operates, making oscillation impossible. Further, since the DC power supply 6 is charged with a voltage approximately twice as high as in a steady state, deterioration is accelerated and damage is likely to occur. Note that 14 indicates a high voltage distribution system.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned conventional drawbacks, prevent oscillation failure due to transient phenomenon surge voltage, prevent overcharging of a DC power supply, and enable stable oscillation.

Composition of the Invention The present invention connects a low voltage capacitor and a high voltage capacitor in series to a first switch connected to a high voltage distribution system, a low voltage side and a high voltage side of a two-winding coupled reactor, respectively, and connects a first thyristor and a high voltage capacitor to each other in series. A first composite element having a first diode connected in antiparallel is connected to the low voltage side in parallel via the low voltage capacitor, and a second composite element having a second thyristor and a second diode connected in antiparallel is connected to the low voltage capacitor. a series inverter connected in series between the
A distribution line signal injection device is configured by providing a second switch for turning on and off the input of the DC power supply, and a third switch is provided in parallel on the output side of the series inverter, and when the first switch is turned on, Turn on the third switch
However, the third switch is turned off in advance when the second switch is turned on.

DESCRIPTION OF EMBODIMENTS Hereinafter, one embodiment of the present invention will be described with reference to FIG.
This will be explained along with FIG.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
11, 12, 13, and 14 are respectively a two-winding coupled reactor, a low voltage capacitor, a reactor, a high voltage capacitor, an injection impedance, a DC power supply, and a first
thyristor, second thyristor, first diode,
They are a second diode, a first switch, a second switch, a relay, and a high-voltage power distribution system. In the present invention, a third switch 15 is connected in parallel to the output side of the series inverter.

Next, the first, second and third switches 11, 12, 1
The opening/closing procedure of No. 5 will be explained using the time chart shown in FIG. If the time when the first switch 11 is turned on and connected to the high voltage distribution system 14 is t ₁ , then the second switch 1
2 is turned OFF, and the third switch 15 is turned ON before t ₁ , and the transient phenomenon surge voltage generated on the low voltage side of the two-winding coupled reactor 1 by the closing of the first switch 11 is switched to the third switch 15. short circuit. Next, several cycles after the transient surge voltage becomes a steady voltage,
t Turn off the third switch 15 for ₂ hours, and then turn off the second switch 15.
Turn on the switch 12 to start oscillation. In this way, the series inverter and the DC power supply 6
Since the transient phenomenon surge voltage has no effect on the DC power supply 6, the DC power supply 6 is not overcharged and stable oscillation is possible.

Effects of the Invention According to the present invention, it is possible to prevent a transmitter in a distribution line conveyance system from becoming unable to oscillate due to a transient surge voltage that occurs when it is connected to a high-voltage distribution system, and to prevent overcharging of a DC power supply. , stable oscillation is possible. It has excellent effects.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of a conventional distribution line signal injection device.
Figure 2 is a high voltage side transient current waveform diagram when the first switch is closed, Figure 3 is a low voltage side transient current waveform diagram when the first switch is closed, and Figure 4 is an embodiment of the present invention. The circuit diagram of the transient phenomenon surge voltage protection device for the distribution line signal injection device in Figure 1 is shown in Figure 1.
~ This is the closing time chart of the third switch. 1... Two-winding coupled reactor, 2... Low voltage capacitor, 3... Reactor, 4... High voltage capacitor, 5... Injection impedance, 6... DC power supply, 7... First thyristor, 8... Second Thyristor, 9...first diode, 10...second diode, 11...first switch, 12...second switch, 14...high voltage distribution system, 15...third switch.

Claims (1)

[Claims] 1. A low-voltage capacitor and a high-voltage capacitor are connected in series to the first switch connected to the high-voltage distribution system and to the low-voltage side and high-voltage side of the two-winding coupled reactor, respectively, and the first thyristor and the first diode are connected in antiparallel. The connected first composite element is connected in parallel to the low voltage side via the low voltage capacitor, and a second composite element having a second thyristor and a second diode connected in antiparallel is connected in series between the low voltage capacitor and the DC power supply. A distribution line signal injection device is configured by providing a second switch connected to the DC power source and turning on/off the input of the DC power supply, and a third switch is provided in parallel to the first composite element, and a third switch is provided in parallel to the first composite element, A transient phenomenon surge voltage protection device for a distribution line signal injection device, wherein the third switch is turned on in advance when the second switch is turned on, and the third switch is turned off in advance when the second switch is turned on.