JPH0143915B2 - - Google Patents

Description

[Detailed Description of the Invention] When connecting an AC transmission/distribution line at its intermediate point, the present invention uses a voltage detection function to determine whether the line is charging or not charging, and This relates to a phase detector that uses a phase detection function to determine whether the electrical circuits are in phase or out of phase when they are being charged.

Generally, when repairing three-phase power transmission and distribution lines, etc., the construction section is electrically disconnected, the wires are replaced, etc., and then electrically reconnected after the construction is completed. For this reconnection, for example, as shown in FIG. 1, electric wires 3a, 3b, 3c, 3a',
Contact the phase detectors 4 and 5 to 3b' and 3c' to confirm that the electric circuits on both sides to be connected, for example 3c and 3c', are in a charged state, and then make sure that both electric wires 3c and 3c' are in the same phase. must be confirmed. If this happens, when the electric wires 3c and 3c' on both sides are connected by the vacuum switch 6c, a short circuit will occur if their charging voltages are not in the same phase.

The required performance of such phase detectors 4 and 5 is that the detection level for determining whether or not charging is being set to an appropriate value, and that the detected phase has high accuracy.

The present invention was invented for the purpose of satisfying the above requirements, and the present invention will be described below with reference to embodiments shown in the drawings.

The structure of the phase checker 4 on the transmitting side is shown in FIG. 2, and the structure of the phase checker 5 on the receiving side is shown in FIG. The main body of the phase detector on the side, 8 is the phase detector circuit B described later.
9 and 10 are hook-shaped hanging fittings protruding from the upper parts of the phase detector bodies 7 and 8, respectively, and 11 and 12 are hook-shaped hanging fittings provided at the lower parts of the phase detector bodies 7 and 8, respectively. The protruding legs 13 and 14 are operating insulating rods connected to the legs 11 and 12 via universal joints 15 and 16, and 17 and 18 are transmitting antennas built into the legs 11 and 12, respectively. and receiving antenna 19,
Reference numerals 20 denote indicator lights protruding from the phase detector bodies 7 and 8, respectively, and 21 denotes a sound generator fixedly attached to the phase detector body 8 on the receiving side.

The phase detector having the above configuration is used in a state as shown in FIG. 4 or FIG. 5.

The usage example shown in Figure 4 is a case where three wires to be phase tested are stretched vertically in parallel, and one insulating rod
A worker holding 3 and 14 climbs up the utility pole 1 and holds the wires 3c and 3c on both sides to be phase-tested with the hanging fittings 9 and 10 of the phase checker.
It is suspended from 3c'. To explain the work procedure in this case, first, the hanging fitting 1 of the phase detector 5 on the receiving side
0 is suspended from one electric wire 3c'. Then, the internal phase detection circuit B detects whether or not charging is in progress, and when charging is in progress, the indicator light 20 blinks,
The sound generator 21 is made to generate sound. At this time, the phase detection circuit B detects the phase of the charging voltage of the suspended electric wire 3c' and generates a phase signal on the receiving side. Next, the transmitting side phase detector 4 is suspended from the other electric wire 3c. Then, the internal phase detection circuit A detects whether or not charging is in progress, and when charging is in progress, the indicator light 19 blinks. Furthermore, this phase detection circuit A detects the phase of the charging voltage of the electric wire 3c, carries this transmitting side phase signal on a radio wave, and emits it from the transmitting antenna 17. In the receiving side phase detector 5, this radio wave is received by the receiving antenna 18, and the internal phase detecting circuit B extracts the phase signal generated on the transmitting side. Then, this is compared with the phase signal generated on the receiving side, and if they match, the indicator light 20 is turned off, and the sound generator 21 is turned off.
The operator is informed that the charging voltages of the two electric wires 3c and 3c' to be connected are in phase with each other. If the two do not match, the blinking of the indicator light 20 and the operation of the sound generator 21 will continue, so the operator can know the mismatch. In this way, the device of the present invention confirms that the phase detecting wire is being charged by turning on the indicator lights 19 and 20, and confirms that the phases match by turning off the indicator light 20 and turning off the sound generator 21.
This can be determined by the stoppage of the signal, making it highly reliable and easy to use.

In the usage example shown in Fig. 5, three electric wires to be phase tested are stretched horizontally in parallel, and the method of using the phase detectors 4 and 5 in this case is the same as described above. .

The phase detection circuits A and B built in the phase detectors 4 and 5 to perform the above operation will be explained with reference to FIGS. 6 and 7.

To explain the phase detection circuit A on the transmitting side, a is a detection section, 9 is a hanging fitting that is hung on the electric wires 3a, 3b, 3c to be phase-detected, 11 is a transmitting antenna, 1
1' is a conductor provided on the ground side of the phase detector 4, and a transmitting antenna 11 is used. 22 and 23 are detection capacitors connected in series between the hanging fitting 9 and the conductor 11', 24 is a stray capacitance between the conductor 11' and the ground, and 25 is a capacitor that indicates whether the electric wires 3a, 3b, and 3c are in a charged state or not. A first level detection circuit having a detection level _V1 as shown in FIG. 10, 26 is an electric wire 3a,
Detection level V ₂ as shown in FIG. 10 for converting the AC waveform of the charging voltage of 3b and 3c into a rectangular wave.
When the first level detection circuit 25 detects the state of charge, the second level detection circuit 27 has a state of charge.
A switching circuit 28 generates an ON output when the second level detection circuit 26 performs a detection operation that the input voltage is higher than its detection level _V1 .
29 is a high frequency oscillation circuit that oscillates when the switching circuit 27 generates an ON output; 30 is a mixing circuit; 31 is a high frequency amplifier; 32 is a circuit that generates a flicker signal when the switching circuit 27 generates an ON output; The generated flicker circuit 33 is a driver circuit that causes the indicator light 19 to flicker based on the output of the flicker circuit 32.

Also, to explain the phase detection circuit B on the receiving side,
b is a detection unit, 10 is electric wires 3a', 3b' to be phase-detected,
3c' is a hanging fixture, 12 is a receiving antenna, 12' is a conductor provided on the ground side of the transmitter 5, and the receiving antenna 12 is used. 34 and 35 are detection capacitors connected in series between the hanging fixture 10 and the conductor 12', 36 is the stray capacitance between the conductor 12' and the ground, and 37 is the electric wire 3a', 3b', 3c' that is charged. Detection level as shown in Figure 10 for status or not
a first level detection circuit 38 having a detection level V ₁ and a second level detection circuit 38 having a detection level V ₂ as shown in FIG. A detection circuit 39 is a switching circuit that generates an ON output when the first level detection circuit 37 detects the charging state.
0 is a frequency conversion circuit, 41 is an intermediate frequency amplification circuit,
42 is a detection circuit, 43 is a low-pass filter, 44
is a waveform shaping circuit, 45 is an exclusive OR circuit, 46
5 is a first NAND circuit; 47 and 48 are a first NOT circuit and a second NOT circuit; 49 is a first NAND circuit; 50 is a first AND circuit; 51 is an integrating circuit;
3 is a second AND circuit, 54 is a Ricker circuit, 55 is a low frequency oscillation circuit, and 56 is a driver circuit that drives the indicator light 20 and the sound generator 21 by the output of the low frequency oscillation circuit 55.

The above phase detection circuits A and B are designed to increase detection accuracy.
The detection parts a and b have different detection levels V ₁ and V ₂ . First and second level detection circuits 25, 26
Or 37, 38 are provided.

That is, the first level detection circuits 25 and 37 determine the presence or absence of charging, and the second level detection circuit 2
At 6 and 38, the sinusoidal waveform of the charging voltage is converted into a rectangular wave depending on whether the voltage is above the detection level. The reason for providing two level detection circuits in this way is whether the charging state requires setting the detection level _V1 to a predetermined value (setting a low level will result in too high sensitivity and false detection). The first level detection circuit 2 of
This is because if 5 and 37 are shared as a level detection circuit for phase detection, the point where the phase of the sine wave changes from negative to positive (or from positive to negative) cannot be accurately detected. That is, the waveform conversion for phase detection is preferably a rectangular wave in which all positive (negative) periods of the sine wave rise. This is because it is desirable that the detection level of phase detection be as low as possible.

Next, the above-mentioned operation of the phase detectors 4 and 5 will be explained with respect to the phase detector circuits A and B.

Connect the hanging fitting 9 of the phase detector 4 on the transmitting side to the electric wires 3a, 3.
When suspended from either wire b or 3c, the wire 3
A, 3b, 3c sends a small detection current with a sinusoidal waveform to the ground via the hanging fitting 9, the detection capacitors 22, 23, the conductor 11, and the stray capacitance 24 as shown in A of FIGS. 8 and 9. Flowing. The first level detection circuit 25 outputs a charging state detection signal when the voltage across the detection capacitor 23 becomes larger than the detection level _V1 . This output causes the switching circuit 27 to generate an ON output. Furthermore, this
Once the charging state is detected, the ON output continues for a fixed period of time, for example, 2 to 3 seconds. this
The ON output causes the flicker circuit 32 and driver circuit 33 to operate, and the indicator light 19 starts blinking. At the same time, when the voltage across the detection capacitors 22 and 23 becomes larger than the detection level V2, the second level detection circuit ₂₆ outputs a high level to convert the sine waveform A of the charging voltage of the wire into a rectangular waveform. The low frequency oscillator 28 transmits the low frequency signal to the mixing circuit 3 only during the high level period.
It is outputting to 0. Here, the switching circuit 27
When outputs ON, the high frequency oscillation circuit 29 performs an oscillation operation and outputs it to the mixing circuit 30. Therefore, the mixing circuit 30 transmits the high frequency signal modulated by the low frequency signal to the high frequency amplifier only during the high level period of the rectangular wave. 31 and is emitted from the transmitting antenna 11. When the state of charge is detected in this way, a high frequency wave in which a rectangular wave C which is a phase signal is combined as a low frequency signal is transmitted from the transmitting antenna 11, and the blinking of the indicator light 19 indicates that the transmission is in progress. Can be confirmed.

Further, the phase detection circuit B of the phase detector on the receiving side performs the phase detection operation as follows.

Connect the hanging fitting 10 of the receiving side phase detector B to the electric wires 3a', 3.
b' or 3c', when the electric wire is in a charged state, the first level detection circuit 37 and switch circuit 39 detect the charging state by the same operation as described above, and switch the ON output to the first level. Output to 2AND circuit 53. The second level detection circuit 38 also operates in the same manner as described above, converting the sinusoidal waveform (b) of the charging voltage of the electric wire into a rectangular wave (d) and outputting the same. Further, the transmitting side radio waves emitted from the transmitting antenna 11 are received by the receiving antenna 12, and this high frequency wave is transmitted to a frequency conversion circuit 40, an intermediate frequency amplification circuit 41, a detection circuit 42, a low pass filter 43, and a waveform shaping circuit 44.
The rectangular wave C generated by the second level detection circuit 26 in the phase detector 4 on the transmitting side is extracted.

The rectangular wave C extracted in this way is
It is compared with the rectangular wave D output from the level detection circuit 38 in the following manner, and it is determined whether the phases of the charging voltages of the two wires match or do not match.

First, a case where the phases match will be explained. In this case, as shown in FIG. 8, the phases of both rectangular waves C and D completely match. Therefore, the output of the first NAND circuit 46 receiving the inputs of both rectangular waves C and D is as shown in FIG. 8E. Also, both rectangular waves C,
The signals obtained by inverting D in the first NOT circuit 47 and the second NOT circuit 48 are as shown in FIG. Be like Chi. Then, the output obtained by inputting the outputs E and J to the first AND circuit 50 becomes a zero level output over the entire period as shown in FIG. 8R. Therefore, the output obtained by inputting this to the integrating circuit 51 is also at zero level, and the judgment circuit 5
2 outputs a low-level mismatch output because it is lower than the set level. Therefore, even if the switching circuit 39 outputs a high level signal to detect charging, the second AND circuit 53 outputs a low level signal and does not operate the flicker circuit 54. Therefore, the display 20 goes out and the sound generator 21 does not operate.

On the other hand, if the rectangular waves A and B are out of phase as shown in FIG. 9, the following mismatch detection operation is performed.

When both wires to be phase-compared are in a charged state, rectangular waves C and D generated from charging voltages A and B are output from the waveform shaping circuit 14 and the second level detection circuit 38 by the same operation as described above. Output. These rectangular waves C and D are sent to the first NAND circuit 46 and the
2NAND circuit 49, first and second NOT circuit 47,
48. When input to the exclusive OR circuit 45 composed of the first AND circuit 50, the output shown in FIG. 9 is obtained by the above-mentioned logical operation. In FIG. 9, this output L is a portion where the high level portions of the two types of rectangular waves C and D do not overlap, that is, a portion where the phases are shifted. This output is from the integrator circuit 51
Further, the level is compared with a determination level in a determination circuit 52, and when the magnitude of the phase shift exceeds a certain amount, the determination circuit 52 outputs a high level indicating a mismatch. For this reason,
The output of the 2AND circuit 53 remains at a high level, and the indicator light 20 and sound generator 21 continue to operate due to the operations of the flicker circuit 54, low frequency oscillator 55, and driver circuit 56, indicating a phase mismatch.

In the phase detector 5 on the receiving side of the present invention, the two types of rectangular waves C and D are input to the exclusive OR circuit 45 for phase comparison, so the phase shift can be calculated from 0° to 180°. It can be detected linearly within the range. Therefore, the detection accuracy is high, and the determination level of whether the phases match or do not match in the determination circuit 52 can be easily and accurately set.

In the above embodiment, a wireless method is used to transmit the phase signal from the phase detector 4 on the transmitting side to the phase detector 5 on the receiving side, but this can also be done using a wired method using a transmission cable. good.

As explained above, according to the present invention, there is provided a phase detector which obtains a rectangular wave corresponding to a positive or negative half cycle of a charging voltage AC waveform and performs phase comparison when an AC power transmission/distribution line is being charged. , a detection section having a first level detection circuit having a detection level for determining whether or not the charging state is in the charging state, and a second level detection circuit having a detection level for converting the AC waveform of the charging voltage into a rectangular wave. Placed between the power distribution line and the ground, the state of charge can be detected at an appropriate level, for example, V ₁ in Figure 10.
Set it to . In addition, since phase conversion detection is performed at a low level, for example, _V2 in Figure 10,
Highly accurate voltage detection and phase detection functions can be obtained. In addition, in the phase detector of the present invention, the phase detection function works only when the state of charge is detected by the voltage detection function. The range of change is kept below a certain value, improving reliability. In other words, when the charging voltage is small, the sine wave becomes small as shown by the dotted line in Figure 10, and the width of the resulting rectangular wave becomes small, resulting in a phase detection error. By setting , when the state of charge is detected, the error e will not exceed the magnitude shown in FIG. 10. In other words, the maximum value of the phase detection error can be determined by the ratio of the two types of detection levels V ₁ and V ₂ . This means that in order to use the phase detector of the present invention for both bare wires and insulated wires, the detection parts a,
This means that even if the sinusoidal voltages a and b input to b vary greatly, it is possible to guarantee that the phase detection error is within the maximum set value.

[Brief explanation of drawings]

Figures 1, 4 and 5 are diagrams showing how the phase detector of the present invention is used, Figure 2 is a front view of the phase detector on the transmitting side, and Figure 3 is a front view of the phase detector on the receiving side. Front view, Figure 6 is the phase detection circuit diagram of the transmitting side phase detector, Figure 7 is the phase detection circuit diagram of the receiving side phase detector, and Figure 8 is the phase detection circuit when the phases match. Figure 9 shows the waveform diagram of each part of the phase detection circuit when the phases do not match. Figure 10 shows the relationship between the two detection levels in the detection section and the rectangular wave whose waveform has been converted. It is a diagram. 4... Phase detector on the transmitting side, 5... Phase detector on the receiving side, 3a, 3b, 3c, 3a', 3b', 3c'... Electric wire, 9, 10... Hanging fitting, 11... Transmitting Antenna, 12... Receiving antenna, 19, 20... Indicator light, 21... Sound generator, 25, 37... First level detection circuit, 26, 38... Second level detection circuit, 45... Exclusive logical OR circuit, A... Phase detection circuit on the transmitting side, B... Phase detection circuit on the receiving side, a, b...
Detection unit.

Claims (1)

[Claims] 1. When an AC transmission/distribution line is being charged, a phase detector that obtains a rectangular wave corresponding to the positive or negative half cycle of the AC waveform of the charging voltage and performs phase comparison detects whether or not it is in a charging state. A detection section having a first level detection circuit having a detection level and a second level detection circuit having a detection level for converting the AC waveform of the charging voltage into a rectangular wave is disposed between the AC power transmission and distribution line and the ground. A phase detector characterized by: