JPS5926176B2 - High-voltage part of reactor-type voltage fluctuation absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-voltage part of a voltage fluctuation absorbing device that is directly connected to a high-voltage distribution line.

The device of the present invention, as shown in FIG.
The purpose of this invention is to control the firing angle of the thyristor stack SCR and change the current flowing through the reactor L to absorb the voltage fluctuation caused by the variable load VL connected to the reactor L.

C is a capacitor for power factor improvement. A high-voltage power distribution line has a line impedance equivalently represented by reactance and resistance, so when the current flowing through the reactor L increases, the voltage decreases, and when the current decreases, the voltage increases. This property is used to absorb voltage fluctuations. Conventionally, 6
This type of device connected to a power distribution line of about kV is equipped with a reactor L or a thyristor stack SC, as shown in Figure 1.
A method has been adopted in which R is directly connected to the line, but in this case, since the lightning surge voltage is directly received, the thyristor stack SCR receives the overvoltage directly, so a protection device such as an arrester Al installed in the stack , a method is taken to prevent destruction of the thyristor stack SCR.

0 In the case of Figure 1, if a steep lightning surge voltage enters,
Although the wave front steepness is alleviated to some extent by the capacitor C, the effect of reducing the wave height value is small, and the method of protecting the thyristor stack SCR using arrester Al, etc. in the thyristor stack SCR as described above is recommended. However, each part is exposed to relatively high voltage, which is not preferable.

The present invention improves the lightning voltage suppression method and develops a device that can be directly connected to high-voltage distribution lines. To explain the present invention in detail with the help of drawings, Fig. 2 shows an embodiment of the present invention. or disconnection.

Although FIG. 2 shows a single-phase system for convenience of explanation, in reality, three sets of similar devices are often made and used in a three-phase system5. Reactors Li and L2 may be wound around the same iron core. In this figure, the thyristor stack SCR and the DC detector DC are not connected directly to the line, but the lightning surge can enter through the reactor no matter which side of the line it is viewed from. Stray capacitance C' of reactors Li and L2 and intermediate tap T of the reactor
In a series circuit with capacitor C inserted between i and T2, almost no lightning surge voltage is applied to capacitor C due to the condition C>C17). 5. Therefore, the potential difference applied to both ends of the thyristor stack SCR can be reduced.

After providing sufficient protection against lightning in this way, the DC current flowing through the reactors L1 and L2 is detected by a DC detector and a thyristor stack is installed to prevent DC current from flowing into the reactors. In addition to controlling the SCR, in the event that an excessive DC current flows, the switch S shown in Fig. 2 is automatically opened to protect the SCR.

If such a protection system is not provided, the amount of direct current generated when the firing angle of the thyristor stack SCR becomes unbalanced will be excessive, which is dangerous, compared to the case where the reactor is connected through the transformer. FIG. 3 is a diagram showing the inside of the thyristor stack SCR of FIG. 2.

After the surge is sufficiently absorbed by the arrester AL, resistor R, capacitor C, etc. in this way, the circuits are connected in series to obtain the necessary withstand voltage. FIG. 4 shows an example of the detection section of the direct current detector DC.

In this figure, when a DC component and an AC component flow through conductor A at the same time, the magnetic flux of the AC component is canceled by the coil w, and only the magnetic flux of the DC component is applied to the hollister H, and this output is amplified and applied to the protection circuit. . In addition to this, the DC detector DC may be of a type in which the voltage applied to both ends of the shunt is amplified by a DC amplifier and the signal is sent by light. As described above, according to the present invention, a reactor-type voltage fluctuation absorbing device that can be directly connected to a high-voltage power source can be produced.

This eliminates the need for a transformer, making it possible to reduce the size and weight of the device.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram showing a conventional system. FIG. 2 shows an embodiment of the present invention, which shows an improvement of the portion indicated by the dotted line in FIG. FIG. 3 is a wiring diagram showing the inside of the thyristor stack SCR of FIG. 2. FIG. 4 is an explanatory diagram of one embodiment of the DC detection section of the DC detector DC. R. S.
T is a three-phase AC high-voltage distribution line, L... is a load that repeatedly fluctuates at a high frequency that cannot be responded to by a tap-switching voltage regulator (referred to as a variable load in this text), L...・・・・・・Reactor, SCR・・・・・・Thyristor stack connected in anti-parallel, C：Capacitor, E：
... is a high voltage AC power supply of about 6kV, S... is a switch, TC... is a trip coil attached to the switch, L1, L2 are reactors, T1, T2 are the above Intermediate tap of the reactor, DC... is the direct current detector, R... is the electrical resistance, AL... is the arrester, and A... is the current to be detected. is the conductor that leads, W... is the coil, 1... is the iron core,
H... is a Hall effect element, Hollister.

Claims (1)

[Claims] 1 Connect one end of switch S to one end of power supply E,
Connect the load side of reactor L_1 to reactor L_
A thyristor stack SCR and a DC detector DC are connected in series between 1 and L_2, and a reactor L
A capacitor C is connected between intermediate taps T_1T_2 of _1 and L_2, the other end of the reactor L_2 is connected to the other end of the power supply E, and the detected voltage of the DC detector DC is applied to the trip coil TC of the switch S. High-voltage part of the reactor-type voltage fluctuation absorption device.