JPS6153663B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulse generation method for a high-voltage pulse application device used for searching for a ground fault point on an overhead power distribution line using a high-voltage pulse application method.

Conventional high-voltage pulse charging devices (hereinafter referred to as charging devices) generate high-voltage pulses at a constant repetition period T, but due to fluctuations in the power supply voltage and the magnitude of grounding resistance, the voltage of the high-voltage pulses may vary. If the value fluctuates, especially if this voltage value becomes low, there are drawbacks such as decreased exploration performance, wasted time, and decreased exploration efficiency.

FIG. 1 is a diagram showing a state in which a conventional power charging device is connected to a power distribution line, and 1 in FIG. 1 is the power charging device. The power supply device 1 constitutes a high voltage pulse generation circuit with a high voltage power supply 10, a current limiting resistor 11, a power supply capacitor 12, a vacuum switch 13, a line grounding resistor 14, and a current supply capacitor 15, and further includes a power supply 16 and a resistor 17. , capacitor 18, coil 13-4 of vacuum switch 13, thyristor 1
9. The thyristor trigger pulse generator 20 constitutes a drive circuit for the vacuum switch 13. In addition,
13-1 is a normally open contact of the vacuum switch 13;
-2 is a normally closed contact, and 13-3 is a common contact.

Further, 2 is the power distribution line, 3 is the ground, 4 is the grounding resistance at the fault point, and 5 is the capacitance of the power distribution line.

Next, the operation of the conventional power charging device shown in FIG. 1 will be explained with reference to FIGS. 2 to 4. now,
As shown in FIG. 2b (A-B voltage), when the power supply capacitor 12 is charged to the output voltage VH of the high-voltage power supply 10, the trigger pulse generator 20 The thyristor 19 is triggered by a trigger pulse VT as shown in ), and the coil 13-4 of the vacuum switch 13 is driven by the energy of the capacitor 18. As a result, the common contact 13-3 of the vacuum switch 13 is activated, the normally open contact 13-1 is closed, and the power distribution line 2 is connected to the
-B voltage) is applied. When the energy of the capacitor 18 is consumed, the coil 13 of the vacuum switch 13 -
4 is deenergized and common contact 13-3 returns to normally closed contact 13-2.

At this time, the high voltage pulse VP is connected to the contact B by the line grounding resistor 14 and becomes a substantially rectangular wave. The above operation is repeated for each trigger pulse VT of a constant period T from the trigger pulse generator 20. As shown in Figure 2a, the trigger pulse VT has a waveform between D and E, but this trigger pulse VT is a rectangular wave with a constant period, and is a waveform of a monostable multivibrator (not shown). It is generated by a pulse oscillator such as

In addition, the waveform of the voltage between A and B shown in FIG. It discharges and then charges again at VH, resulting in an approximately sawtooth waveform.

Further, the voltage between C and B shown in FIG. 2c is a high voltage pulse VP, which, as described above, is applied between the distribution line 2 and the ground 3 in the form of a substantially rectangular wave.

Now, since the period T of the high voltage pulse VP is constant, the following problems occur, which is a drawback. FIG. 3 shows a case where the ground resistance 4 at the fault point is extremely small. That is, when the value of the grounding resistance 4 is extremely small, a large amount of the energy of the power supply capacitor 12 is discharged during the operation of the vacuum switch 13, and therefore the voltage v across it (FIG. 3b)
becomes extremely low voltage.

Therefore, since the voltage at the start of the next charging is low, it takes a long time to reach the output voltage VH of the high voltage power supply 10, and during that time the trigger pulse VT
is generated, the vacuum switch 13 is activated at a point where the voltage v across the power supply capacitor 12 is low.
As a result, the voltage of the high voltage pulse VP also becomes low as shown in FIG. 3c. This means that a voltage pulse lower than the specified voltage is applied to the power distribution line 2, and the required performance of fault point exploration is degraded. Note that FIG. 3a shows the trigger pulse VT similarly to FIG. 2a.

Next, we will discuss the case where the grounding resistance 4 is extremely large. In this case, each signal is as shown in Figures 4a to 4c. Because of the value, when the vacuum switch 13 is activated, the power supply capacitor 12
consumption of energy is small. Therefore, as shown in FIG. 4b, the voltage v across it does not drop significantly, and the output voltage VH of the high-voltage power supply 10 increases during the next charging.
The charging time reached will be faster.

Therefore, after charging is complete, the next trigger pulse VT
(Fig. 4a) will be a waste of time. Generally, the shorter the period T of the trigger pulse VT, the better the exploration efficiency, so this wasted time must be minimized.

As mentioned above, conventional pulse generation methods have drawbacks, resulting in decreased exploration performance and exploration efficiency.

This invention was made to eliminate the above-mentioned conventional drawbacks, and aims to provide a pulse generation method for a high-voltage pulse energizing device that makes it possible to improve exploration efficiency and shorten exploration time. .

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a pulse generation method for a high-voltage pulse charging device of the present invention will be described with reference to the drawings. FIG. 5 is a circuit diagram connecting a high voltage pulse charging device and a power distribution line applied to one embodiment of the present invention. In FIG. 5, parts that are the same as or correspond to those in FIG. 1 are given the same reference numerals to avoid redundant explanations, and parts that are different from those in FIG. 1 will be mainly described.

In FIG. 5, 21 and 22 are newly added resistors that divide the voltage v across the power supply capacitor 12. Therefore, the resistors 21 and 22 are connected in series, and the series connection body is connected in parallel to the power supply capacitor 12.

A connection point between resistors 21 and 22 is connected to a non-inverting input terminal of a voltage detector 23. Voltage detector 23
compares the voltage vd divided by the resistors 21 and 22 with the reference voltage e from the variable pressure source 24, and generates an output when the divided voltage vd becomes higher than the reference voltage e; for example, Comparators etc. are used.

Further, 25 is a timing circuit. This timing circuit 25 is a trigger signal for the thyristor 19.
Two types of after-time signals, T1 and T2, are generated based on the signal that the VT and the control power source (not shown) are changed from "off" to "on". The output terminal of this timing circuit 25 is connected to the second output terminal of the AND circuit 26.
and the second input terminal of the OR circuit 27. The output terminal of the voltage detector 23 is connected to a first input terminal of the AND circuit 26 .

As is clear from the above explanation, the AND circuit 26 combines the output of the voltage detector 23 with the timing circuit 2.
This is to perform AND control with the T2 output of 5.
The output terminal of the AND circuit 26 is connected to the first input terminal of the OR circuit 27. Therefore, the OR circuit 27 performs OR control of the output of the AND circuit 26 and the T1 output of the timing circuit 25.

The output terminal of the OR circuit 27 is connected to the input terminal of an amplifier 28. The output terminal of the amplifier 28 is connected to the gate of the thyristor 19 and output to the timing circuit 25.
The other configurations are exactly the same as in FIG. 1.

Next, the operation shown in FIG. 5 will be explained with reference to the waveform diagrams from FIG. 6 onwards. First, starting from the case of Fig. 6, the charging voltage v of the power supply capacitor 12 after the vacuum switch 13 is activated (Fig. 6 a) and the voltage vd divided by the resistors 21 and 22 are calculated from Fig. 6 a. are also clearly similar.

Now, when the power supply capacitor 12 is being charged, when the divided voltage vd becomes higher than the reference voltage e, an output is output from the voltage detector 23 and is applied to the first input terminal of the AND circuit 26. The T2 output from the timing circuit 25 is introduced into the second input terminal of the AND circuit 26, and the T2 output and the output of the voltage detector 23 are ANDed, and as a result,
The output of the voltage detector 25 is output from the AND circuit 26 and is applied to the amplifier 28 through the OR circuit 27. After being amplified here, thyristor 1
A trigger pulse VT (FIG. 6b) is generated to be applied to the gate of 9.

This pulse triggers the thyristor 19, and the coil 13-4 of the second vacuum switch 13 is energized by the charge of the capacitor 18, causing the common contact 13-3 of the vacuum switch 13 to become the normally open contact 13-1. Contact.

Therefore, if the reference voltage e is determined, the charging voltage v of the power supply capacitor 12 will always be at a constant point Vc.
The vacuum switch 13 is activated, and the voltage of its output, the high voltage pulse VP (FIG. 6b), also becomes constant.

Further, FIG. 7 shows a case where the grounding resistance 4 is smaller than that in FIG. 6, and the voltage at the start of charging becomes a low voltage as in FIG. 3. However, the charge voltage v is the seventh
Since the vacuum switch 13 is activated after reaching VC as shown in Figure a, the high voltage pulse VP (7th
Figure b) is equal to Vc. Note that FIG. 7c shows the trigger pulse VT applied between the gate and cathode of the thyristor 19.

In addition, the case of FIG. 8 shows a case where the grounding resistance 4 is larger than the case of FIG. 6, and as in FIG. Vc reached, vacuum switch 1
3 is activated, so the high voltage pulse VP is equal to Vc.

In this way, it becomes a kind of automatic control, and regardless of the magnitude of the grounding resistance 4 at the fault point, high voltage pulse
VP becomes a constant voltage value, which means that the exploration performance does not change depending on the magnitude of the grounding resistance 4. However, when the grounding resistance 4 is extremely small (for example, 0Ω), the voltage at the start of charging after the vacuum switch 13 is activated is about 0V, as shown in FIG. Therefore, it takes a long time to charge the voltage up to the operating point of the vacuum switch 13, and the exploration efficiency decreases.

In addition, if the ground resistance 4 is extremely large, the 10th
As shown in the figure, after the vacuum switch 13 is activated, the voltage at the start of charging is very high, and the vacuum switch 13 is activated.
It takes a short time to charge the voltage up to the operating point of the vacuum switch 13, and the number of operations of the vacuum switch 13 increases. As a result, the life of the vacuum switch 13 is shortened, and various devices connected to the power distribution line 2 (for example, high-voltage transformers, sectional switches, etc.) are more likely to be damaged, which is undesirable.

In such a case, as shown in FIG. 9, a trigger pulse is generated by the T1 output of the timing circuit 25 to activate the vacuum switch 13 early. At this time, the high voltage pulse VP will be slightly lower than VC, and the exploration performance will deteriorate somewhat, but wasted time will be eliminated and the exploration efficiency will be greatly improved.

Further, as shown in FIG. 10, even if the divided voltage vd becomes higher than the reference voltage e of the voltage detector 23 and generates an output, if the T2 output of the timing circuit 25 does not come out, the vacuum switch 13 not working,
When the T2 output occurs, a trigger pulse is generated by the amplifier 28, and the vacuum switch 13 is activated. Therefore, the vacuum switch 13 does not operate frequently and has a long lifespan, and the power distribution line 2
There will also be no impact on high voltage equipment connected to the

It is obvious in a general time constant circuit using a resistor and a capacitor that the output voltage VH of the high voltage power supply 10 must be higher than the voltage VC at the operating point of the vacuum switch 13.

FIGS. 11 and 12 are waveform diagrams for explaining another embodiment of the present invention. Among these, in FIG. 11, as mentioned above, the trigger pulse VT is the divided voltage vd similar to the charging voltage v, and the reference voltage e
When the reference voltage e is generated when the voltage becomes higher, and when the high voltage pulse VP is generated, the reference voltage e is set to e1, e2, e3 (the first
When the voltage is changed to Fig. 1a), the point at which the trigger pulse VT is generated by the voltage detector 23 is also changed, and as a result, the voltage VC at the operating point of the vacuum switch 13 is also changed. This makes it possible to vary the voltage value of the high voltage pulse VP (FIG. 11b).

In the case of FIG. 12, as described above, when the grounding resistance 4 is extremely small, the voltage at the start of charging of the power supply capacitor 12 is low, and it takes a long time to charge it to the voltage VC at which the vacuum switch 13 operates. Ru.
At this time, a trigger pulse is generated by the T1 output of the timing circuit 25, and a high voltage pulse is generated.
VP is generated.

In such a case, the internal time change section (not shown) of the timing circuit 25 is changed to change its output to T.
1, T2, and T3 (Fig. 12a), the trigger pulse generation point can also be varied, and the vacuum switch 1
The voltage VC at the operating point in step 3 also changes. This makes it possible to vary the voltage value of the high voltage pulse VP (FIG. 12b).

As detailed above, according to the present invention, the drawbacks of the conventional methods can be overcome, and therefore,
It is possible to improve exploration efficiency and shorten exploration time.
This provides an extremely large advantage in detecting fault points on power distribution lines, and in turn contributes to a stable supply of electricity through early restoration in the event of an accident.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the connection state between a conventional high-voltage pulse charging device and a power distribution line, and Figures 2a to 2c to 4a to 4c are the operating waveforms of Figure 1, respectively. 5 is a circuit diagram of a high voltage pulse charging device applied to an embodiment of the pulse generation method of the high voltage pulse charging device of the present invention, and FIGS. 6a to 6c to 10 FIGS. 11a to 10c are operation waveform diagrams for explaining one embodiment of the pulse generation method of the high voltage pulse charging device of the present invention, FIGS. 11a and 11b, and FIGS. 12a and 12c, respectively. FIG. 12b is an operation waveform diagram for explaining another embodiment of the pulse generation method of the high voltage pulse energizing device of the present invention. 1... Power charging device, 2... Distribution line, 3... Earth, 4... Earthing resistance, 10... High voltage power supply, 12...
...Power supply capacitor, 13...Vacuum switch, 14
...Line grounding resistance, 15...Current supply capacitor, 16...Power supply, 18...Capacitor, 9
...Thyristor, 21, 22...Resistor, 23...
Voltage detector, 24... variable voltage power supply, 25... timing circuit, 26... AND circuit, 27... OR circuit, 28... amplifier. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. Applying the voltage of a high-voltage power supply to a power supply capacitor to store energy, and applying the energy as a high-voltage pulse to the power distribution line via a vacuum switch, and supplying current to the output side of the vacuum switch. In a high voltage pulse charging device equipped with a power supply capacitor, the voltage across the power supply capacitor is compared with a predetermined reference voltage by a voltage detector, and when the voltage across the power supply capacitor exceeds the reference voltage, an output from the voltage detector is generated. drives the coil of the vacuum switch, switches the contact of the vacuum switch to the power supply capacitor side, applies a predetermined high voltage pulse to the distribution line, and if the period of applying this high voltage pulse changes beyond a predetermined value, A pulse generation method for a high voltage pulse energizing device, characterized in that a high voltage pulse is applied to the power distribution line by driving a coil of the switch at a predetermined period to switch contacts of the vacuum switch. 2. Claims characterized in that the voltage of the high-voltage pulse generated is varied by changing the detection level of a voltage detector, and the voltage of the high-voltage pulse is varied by changing the generation period of this high-voltage pulse. 2. A pulse generator for a high-voltage pulse charging device according to item 1.