JP2000162258A - Phase-detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize phase detection by a simple means to a distribution line, at a point isolated far from a substation or the like. SOLUTION: Phase-detecting devices 11 and 12 determines whether or not distribution lines 13 and 14 at two points separated far from each other have an equal phase or different phases. The detecting devices are provided with detecting parts 15 and 16 at the transmission side and reception side which detect phase voltages of the distribution lines 13 and 14 to ground at each phase detection point and output phase detect signals, an interface part 17 at the transmission side for converting the phase detect signal of the detecting part 15 to a transmission signal through a pulse frequency conversion, and sending the transmission signal to a commercially available transceiver 19 at the transmission side, and a interface part 18 at the reception side for converting a receive signal at a commercially available transceiver 20 to the phase detect signal of the detecting part 15 through a frequency pulse conversion, comparing the phases of the phase detect signal of the detecting part 15 and the phase detect signal of the detecting part 16, thereby determining and displaying, based on the comparison result whether or not the distribution lines 13 and 14 have the identical phase or different phases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase detector, and more particularly, to a phase detector for identifying each phase of a three-phase AC distribution line at two points separated from a substation and a distribution line.

[0002]

2. Description of the Related Art In general, in a power system, an electric power customer is terminated at a power transmission line from a substation via a transmission line stepped down to 6600 V, and power is supplied from the distribution line to the electric power customer. I am trying to do it. This distribution line is generally of a three-phase alternating current, and includes, for example, a U-phase, a V-phase, and a W-phase.

[0003] In such a power system, the end of one distribution line and the end of the other distribution line may be butt-connected in a distribution line change work or the like. At the time of this butt connection, the U-phase,
If the V phase and the W phase are mistaken, there is a possibility that a supply failure accident due to a short circuit between phases occurs, or a serious accident that the motor rotates reversely when the electric power consumer tries to rotate the motor forward, for example.

[0004] In order to prevent such a serious accident due to the erroneous identification of each phase, in the above-mentioned distribution line system change work, etc., before connecting and connecting one distribution line and the other distribution line, The one and the other distribution lines are matched and phase-checked. As shown in FIG. 8, the phase matching of the three-phase distribution lines 3 and 4 is performed by using the phase detectors 1 and 2 as shown in FIG.

[0005] In the butt phase detection by the phase detectors 1 and 2, the phase detector 1 is electrically connected to one distribution line 3 and the phase detector 2 is also electrically connected to the other distribution line 4. . These two phase detectors 1 and 2 are electrically insulated by optically connecting the detection units 5 and 6 with an optical fiber cable 7. Then, a phase detection signal is transmitted from the detection unit 5 of the one phase detector 1 to the other phase detector 2 via the optical fiber cable 7, and the detection unit of the other phase detector 2 is referred to based on the phase detection signal. 6 to determine whether the phase is the same or different.

The determination of these two phase detection signals is performed in the following manner by the circuit configuration including the exclusive OR circuit 8 and the integration circuit 9 shown in FIG. As shown in FIG. 10A, when one distribution line 3 and the other distribution line 4 are in phase, a phase detection signal at the detection unit 5 of one phase detector 1 (FIG. 10).
When the exclusive-OR circuit 8 inputs the signal and the phase detection signal from the detection unit 6 of the other phase detector 2 (shown in the figure), the output signal (shown in the figure) is always low level, No voltage is generated in the output signal (shown in the figure).

Conversely, when one distribution line 3 and the other distribution line 4 are out of phase as shown in FIG.
When the phase detection signal (FIG. 5) of the detection unit 5 and the phase detection signal (FIG. 6) of the detection unit 6 of the other phase detector 2 are input to the exclusive OR circuit 8, the output signal (FIG. (FIG. 2) becomes high level only when the two phase detection signals are at different levels, and a voltage is generated in the output signal (FIG. 2) of the integration circuit 9 at the subsequent stage.

In this manner, it is possible to determine whether one distribution line 1 and the other distribution line 2 are in phase or out of phase by the presence or absence of the generation of a voltage. The worker can be notified by turning on a display lamp or sounding a buzzer.

[0009]

In the conventional phase detectors 1 and 2 described above, the phase detector 1 attached to one distribution line 3 and the phase detector 2 attached to the other distribution line 4 are used.
Are connected by an optical fiber cable 7, and the butt phase detection by the phase detectors 1 and 2 is based on the premise that the distribution lines 3 and 4 to be detected exist very close to each other. The distance is limited to within a few meters. For this reason, for example, it is impossible at present to detect a distribution line at a point far away from a substation or the like.

Therefore, the present invention has been proposed in view of the above-mentioned problems, and an object thereof is to realize, for example, a phase detection of a distribution line at a point far away from a substation or the like by simple means. It is to provide a phase detector which can be used.

[0011]

SUMMARY OF THE INVENTION As a technical means for achieving the above-mentioned object, the present invention provides a phase detection method for judging whether two phase detection lines are in phase or out of phase. A transmitting and receiving side detecting unit for detecting a ground phase voltage of a phase detection target line at each phase detecting point and outputting the detected voltage as a phase detecting signal, and a phase detecting signal of the transmitting side detecting unit. A transmission interface unit that converts the transmission signal to a commercially available transmission-side transceiver by converting the transmission signal to a commercially available transmission-side transceiver by a pulse frequency conversion, and a phase detection signal of a transmission-side detection unit by performing a frequency pulse conversion on the reception signal from the commercially available reception-side transceiver. , And compares the phase of the phase detection signal of the transmission side detection unit with the phase of the phase detection signal of the reception side detection unit. Based on the comparison result, the reception side interface determines and indicates whether the phase detection target line is in phase or out of phase. Department Characterized in that Bei was.

According to the present invention, there is provided a transmission-side interface unit for converting the phase detection signal of the transmission-side detection unit into a pulse frequency so that the signal can be transmitted by a commercially available transmission-side transceiver.
The transmission signal from the transmitting transceiver is received by a commercially available receiving transceiver, and the received signal of the receiving transceiver is subjected to frequency pulse conversion so that each phase of the phase detection target line can be identified, and the detection of the receiving detector is performed. A receiving-side interface unit for comparing and judging the phase of the phase signal and displaying the result is provided.
As a result, it is possible to perform the phase detection work even at a place as far away from the substation as several km or several tens km.

The transmission-side interface unit converts the audio-frequency pulse signal into a sine-wave signal by waveform shaping, and converts the audible-frequency sine-wave signal into a commercial-frequency detection signal input from the transmission-side detection unit. By adding
A configuration in which the signal is a transmission signal of the transmission-side transceiver is possible.

The receiving-side interface unit converts the received signal of the receiving-side transceiver into a phase-detected signal of the transmitting-side detecting unit by frequency pulse conversion, and detects the signal based on the phase-detected signal input from the receiving-side detecting unit. By generating a pulse signal and comparing the phase of the phase detection signal of the transmitting side detection unit with the detected pulse signal as a criterion, it is possible to generate a display output that determines whether the phase is the same or different based on the comparison result. It is.

Further, the reception-side interface unit can arbitrarily set the phase detection sensitivity for judging in-phase or out-of-phase by adjusting the rise time of the detection pulse signal, which is a criterion.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a phase detector according to the present invention will be described in detail below.

The phase detectors 11 and 12 according to the present invention are used to connect one of the distribution lines 13 and the other of the distribution lines 14 before butt-connecting the distribution lines in a distribution system change work or the like in an electric power system. Distribution line 13 and other distribution line 1
4 and performs phase matching, which is suitable when two phase detection points are separated by a distance of several km or several tens km.

The phase detectors 11, 12 of the embodiment shown in FIG.
A transmitting side that detects a ground phase voltage of the distribution lines 13 and 14 that are detection target lines at respective phase detection points separated by a distance of several km or several tens km, and outputs the detected voltage as a phase detection signal; Receiving side detecting sections 15 and 16 and transmitting side detecting section 1
5 is converted into a transmission signal by pulse frequency conversion, and the transmission interface unit 17 for transmitting the transmission signal to a commercially available transmission transceiver 19 and the reception signal at the commercially available reception transceiver 20 are subjected to frequency pulse conversion. To a phase detection signal of the transmission side detection unit 15, a phase comparison is made between the phase detection signal of the transmission side detection unit 15 and the phase detection signal of the reception side detection unit 16, and based on the comparison result, each distribution line A receiving side interface unit 18 for judging and displaying whether the phases 13 and 14 are in-phase or out-of-phase is provided.

In the configuration of the phase detectors 11 and 12 described above, the transmitting side and receiving side detecting sections 15 and 16 are configured such that the hook-shaped detecting metal fittings at the tips are hooked to the distribution lines 13 and 14 and locked. Distribution line 1 electrically connected to distribution lines 13 and 14 and detected by respective detection units 15 and 16
3 and 14 to the optical fiber cables 21 and 22
And receiving side interface units 17 and 1
8 by optical transmission.

As described above, the transmitting-side and receiving-side detectors 15,
16 and transmission-side and reception-side interface units 17 and 18
Are electrically insulated by optically connecting them with optical fiber cables 21 and 22. Further, as the commercially available transmitting and receiving transceivers 19 and 20, for example, those having a transmission frequency of a 400 MHz band or a 150 MHz band are preferably used.

The transmission-side interface unit 17
It has an appearance as shown in FIGS. A power switch 24 for turning on and off the power, a press talk switch 2 for a call are provided on a front operation surface of the main body case 23.
5, a switch 26 such as a toggle switch for switching between a call state and a data transmission state, and a call condenser microphone 27 and a speaker 28 are provided. Also, an input lamp 29 that lights up when the phase detection signal of the transmission side detection unit 15 is input, a transmission lamp 30 that lights up when transmitting to the transmission side transceiver 19, and a low battery lamp 31 that warns when the battery is low. Are arranged.

An input terminal 32 to which the optical fiber cable 21 extending from the transmitting side detecting section 15 is connected and a connector 33 for connecting to the transmitting side transceiver 19 are provided on the upper surface of the main body case 23. The connector 33 can be replaced with an appropriate connector according to the type of the transmission-side transceiver 19, for example, the shape of the connection terminal and the number of pins.

The transmission side interface unit 17 has a circuit configuration as shown in FIG. That is, based on the input from the optical fiber cable 21, the discrimination circuit 34 that removes unnecessary signal components such as noise signals and harmonic signals other than the pulsed phase detection signal of the commercial frequency (for example, 50 Hz).
An audible pulse generating circuit 35 for generating a pulse signal of an audible frequency (1 kHz), a waveform shaping circuit 36 for converting the pulse signal into a sine wave signal by shaping the waveform with, for example, a band pass filter (BPF) or the like; Frequency of the phase detection signal from the above-described discrimination circuit 34 (50 Hz)
A gate circuit 37 that generates a transmission signal of an audible frequency (1 kHz) that is intermittently transmitted, and transmits a transmission signal output from the gate circuit 37 to the transmission-side transceiver 19,
In addition, the switching circuit 38 includes a switching circuit 38 for switching input / output of the above-described press talk switch 25, the changeover switch 26, the transmission lamp 30, the speaker 28, the condenser microphone 27, and the like. The input lamp 29 is turned on by the output of the discrimination circuit 34 described above.

Next, the receiving side interface unit 18
It has the appearance as shown in FIGS. On the front operation surface of the main body case 39, there are provided a power switch 40 for turning on / off the power and a press talk switch 4 for a telephone call.
1 is placed, and a condenser microphone for call 42,
A speaker 43 and a piezoelectric buzzer 44 are provided. Also, an input lamp 45 that lights up when the phase detection signal of the receiving side detection unit 16 is input, a receiving lamp 46 that lights up when the receiving side transceiver 20 is receiving, a low battery lamp 47 that warns when the battery is low, An in-phase lamp 48 that lights up when the phase is the same as the result of the phase detection and a different-phase lamp 49 that lights up when the phase is different are provided. When the phase detection result is out of phase, the out-of-phase lamp 49 is turned on and the piezoelectric buzzer 44 sounds.

The transmission-side interface unit 1
7, the receiving side detecting unit 1
An input terminal 50 to which the optical fiber cable 22 extending from 6 is connected, and a connector 51 for connection to the receiving transceiver 20 are provided. Note that this connector 5
1 can be replaced with a suitable one according to the type of the receiving transceiver 20, for example, the shape of the connection terminal and the number of pins.

The receiving-side interface section 18 has a circuit configuration as shown in FIG. That is, a switching circuit 52 that sends a signal received by the receiving transceiver 20 to an amplifier circuit described later, an amplifier circuit 53 that amplifies the output of the switching circuit 52, and a received signal output from the amplifier circuit 53 is connected to a commercial frequency ( For example, a pulsing circuit 54 that converts the signal into a pulse signal (phase detection signal) of 50 Hz, and a reception signal discrimination circuit 55 (hereinafter, referred to as a signal) that removes unnecessary signal components such as noise signals and harmonic signals other than the phase detection signal of the commercial frequency. A first discrimination circuit), and a rise detection circuit 56 for detecting a rise of a phase detection signal output from the first discrimination circuit 55.
And

The above-described switching circuit 52 is used to input a received signal from the receiving transceiver 20, or to switch between input and output of the condenser microphone 42, the speaker 43, and the like. Further, the receiving lamp 46 is turned on based on the output of the first discrimination circuit 55.

Further, based on an input from the optical fiber cable 22, a phase detection signal discrimination circuit 57 (hereinafter, referred to as a second discrimination circuit) for removing noise signals and harmonic signals other than the phase detection signal of the commercial frequency (for example, 50 Hz). ), And a detection pulse for determining whether the reception signal of the reception-side transceiver 20 (the detection signal of the transmission-side detection unit 15) is in-phase or out-of-phase based on the phase detection signal output from the second discrimination circuit 57. A detection pulse generation circuit 58 for generating a signal, a gate circuit 59 for outputting a determination result based on an output from the rise detection circuit 56 based on the detection pulse signal output from the detection pulse generation circuit 58, and a gate thereof. A display circuit 60 for displaying whether the phase detection signal of the transmission side detection unit 15 is in phase or out of phase with the phase detection signal of the reception side detection unit 16 based on the output signal from the circuit 59. It is made.

The in-phase or out-of-phase lamps 48 and 49 are selectively turned on by the output of the display circuit 60,
When is turned on, the piezoelectric buzzer 44 simultaneously sounds.
The input lamp 45 is turned on by the output of the second discrimination circuit 57 described above.

The phase detection operation of the phase detectors 11 and 12 described above will be described in detail below.

First, one transmission line 1
The phase detection signal is output from the transmission side detection unit 15 to the transmission side interface unit 17 via the optical fiber cable 21 by detecting the ground phase voltage 3. At this time, the transmission-side interface unit 17 is in a state where data transmission is possible by switching the changeover switch 26 to the data transmission side, and the transmission lamp 30 is lit. In addition, in order to talk with the worker at the phase detection point of the other distribution line 14, the changeover switch 26 is switched to the audio side, and by using the press talk switch 25, the conversation is performed by the condenser microphone 27 and the speaker 28. It is possible.

When the phase detection signal of the transmitting side detecting section 15 is input to the transmitting side interface section 17, an unnecessary signal component such as a noise signal or a harmonic signal is removed by a discriminating circuit 34.
Only the pulse-shaped phase detection signal of the commercial frequency (for example, 50 Hz) is output (see FIG. 6A). This discrimination circuit 34
The input lamp 29 is turned on by the output signal of.

On the other hand, a pulse signal of an audible frequency (for example, 1 kHz) is output from the audible pulse generation circuit 35, and the pulse signal is converted into a sine wave signal by the waveform shaping circuit 36 (see FIG. 6B). When the phase detection signal output from the above-described discrimination circuit 34 and the sine wave signal output from the waveform shaping circuit 36 are input to the gate circuit 37, the gate circuit 37 converts the phase detection signal of the transmission side detection unit 15 A transmission signal that can be transmitted by the transmission-side transceiver 19 is output.
That is, the frequency of the phase detection signal from the discrimination circuit 34 (50
Hz), a transmission signal of an intermittent audio frequency (1 kHz) is generated (see FIG. 6C) and output to the transmission-side transceiver via the switching circuit 38.

When the transmission signal of the transmission-side transceiver 19 is received by the reception-side transceiver 20 in this manner, the reception signal of the reception-side transceiver 20 is input to the amplification circuit 53 via the switching circuit 52 and amplified. The output signal of the amplifying circuit 53 has an audible frequency (1 kHz) which is intermittent at a frequency (50 Hz), like the transmission signal described above.
z), the output signal of the amplifying circuit 53 is converted into a pulse signal (phase detection signal) of the commercial frequency (50 Hz) by the pulsing circuit 54. Further, the phase detection signal output from the transmission side detection unit 15 output from the pulsing circuit 54 is subjected to a first discrimination circuit 55 in which unnecessary signal components such as a noise signal and a harmonic signal are removed. Is input to the gate circuit 59. The reception lamp 46 is turned on by the output of the first discrimination circuit 55 described above.

On the other hand, the receiving-side detecting section 16 detects a phase-to-ground voltage of the other distribution line 14, and a phase detection signal from the receiving-side detecting section 16 is transmitted to the receiving-side interface section 18 via the optical fiber cable 22. Is output. At this time, in the receiving interface section 18, when the phase detection signal of the receiving side detecting section 16 is input via the optical fiber cable 22, an unnecessary signal component such as a noise signal or a harmonic signal is generated by the second discriminating circuit 57. The second discrimination circuit 57 is removed.
The input lamp 45 is turned on by the output of. When the phase detection signal from the second discrimination circuit 57 is input to the detection pulse generation circuit 58, the reception signal which is the phase detection signal of the transmission side detection unit 15 is received based on the phase detection signal from the second discrimination circuit 57. A detection pulse signal for determining whether the received signal from the side transceiver 20 is in phase or out of phase is generated.

This detection pulse signal is generated as follows. The detection pulse generation circuit 58 includes two monomultivibrators 61 and 62, and one cycle is 20 ms.
The first monomultivibrator 61 is triggered by the rising edge of the phase detection signal (see FIG. 7A) of the receiving-side detector 16 at (50 Hz). The first monomultivibrator 61 generates a pulse signal (see FIG. 7B) with a rise time set to about 18 ms, and triggers the second monomultivibrator 62 at the fall.

The second mono-multivibrator 62 generates a detection pulse signal (see FIG. 7C) whose rise time is set to about 3.3 ms. The rise time (approximately 3.3 ms) of the detection pulse signal output from the second monomultivibrator 62 is an allowable value serving as a criterion for determining that the distribution lines 13 and 14 are in phase. The phase difference of the signal corresponds to about 15 °. Therefore, if the phase difference between the two detection signals of one distribution line 13 and the other distribution line 14 is within 15 °, both distribution lines 1
3, 14 are determined to be in phase.

By adjusting the time constant of the second mono-multivibrator 62, the rise time of the above-described detection pulse signal can be made longer than the above-mentioned about 3.3 ms to lower the sensitivity, or conversely, about 3 ms. It is possible to increase the sensitivity by setting it shorter than 0.3 ms, and in this way it is possible to set any sensitivity as needed, and to perform appropriate phase detection work according to the usage of the phase detector. Can be realized.

As described above, the determination result based on the pulse signal output from the rise detection circuit 56 is output from the gate circuit 59 using the detection pulse signal output from the detection pulse generation circuit 58 as a determination reference. As described above, the receiving side transceiver 2 which is the phase detection signal of the transmitting side detecting section 15
The rising edge of the received signal of 0 (in the case of the same phase) (see FIG. 7D) is detected by the rising edge detection circuit 56, and the rising edge (see FIG. 7E) corresponds to the rising time of the detection pulse signal [FIG. )], The transmission lines 13 and 14 have the same phase on the transmission side and the reception side, and the display circuit 60 based on the output signal from the gate circuit 59 [see FIG. Output turns on the in-phase lamp 48.

The rising edge of the received signal (in the case of a different phase) of the receiving transceiver 20 (see FIG. 7 (g)) is detected by the rising edge detecting circuit 56, and the rising edge [FIG.
(H)] is the rise time of the detection pulse signal [FIG.
(C), the distribution lines 13 and 14 are out of phase between the transmission side and the reception side, and are displayed based on the output signal from the gate circuit 59 (see FIG. 7 (i)). The output of the circuit 60 causes the out-of-phase lamp 49 to light up and the piezoelectric buzzer 44 to emit sound.

[0041]

According to the present invention, a transmitting side interface unit for converting a phase detection signal of a transmitting side detecting unit into a transmitting signal by pulse frequency conversion and transmitting the transmitting signal to a commercially available transmitting side transceiver, The received signal at the receiving transceiver is converted into a phase detection signal of the transmission side detection unit by frequency pulse conversion, and the phase of the phase detection signal of the transmission side detection unit is compared with the phase detection signal of the reception side detection unit. By providing a receiving interface unit for determining and displaying whether the phase detection target line is in phase or out of phase based on the result, phase detection data can be transmitted using a commercially available transceiver. The phase detection work can be realized even between points as far away as 10 km, and a versatile phase detector can be provided.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a phase detector according to the present invention.

2A is a plan view showing an appearance of a transmission-side interface unit shown in FIG. 1, FIG. 2B is a front view of FIG. 1A, and FIG. 2C is a side view of FIG.

FIG. 3 is a block diagram showing a circuit configuration of a transmission-side interface unit in FIG. 1;

4A is a plan view showing the appearance of the receiving-side interface unit in FIG. 1; FIG. 4B is a front view of FIG. 1A; FIG. 4C is a side view of FIG.

FIG. 5 is a block diagram showing a circuit configuration of a receiving-side interface unit in FIG. 1;

6A is a waveform diagram showing an output signal of the discrimination circuit of FIG. 3; FIG. 6B is a waveform diagram showing an output signal of the waveform shaping circuit of FIG. 3; Waveform diagram shown

7A is a waveform chart showing an output signal of a second discriminating circuit of FIG. 5; FIG. 7B is a waveform chart showing an output signal of a first monomultivibrator of the detection pulse generating circuit of FIG. 5; 5D is a waveform diagram showing an output signal of the second monomultivibrator of the detection pulse generation circuit of FIG. 5. FIG. 5D is a waveform diagram showing an output signal of the first discrimination circuit of FIG. A waveform diagram showing an output signal of the rise detection circuit, (f) is a waveform diagram showing an output signal of the gate circuit in the case of the same phase, and (g) is a waveform diagram showing an output signal of the first discrimination circuit in FIG. (h) is a waveform diagram showing an output signal of the rise detection circuit in the case of out-of-phase. (i) is a waveform diagram showing an output signal of the gate circuit in the case of out-of-phase.

FIG. 8 is an overall configuration diagram showing a conventional example of a phase detector.

FIG. 9 is a circuit diagram showing an exclusive OR circuit and an integration circuit that constitute a phase detection circuit;

10A is a waveform diagram showing each output signal in the case of in-phase, and FIG. 10B is a waveform diagram showing each output signal in the case of out-of-phase.

[Explanation of symbols]

 11, 12 phase detector 13, 14 phase detection target line (distribution line) 15 transmitting side detecting unit 16 receiving side detecting unit 17 transmitting side interface unit 18 receiving side interface unit 19 transmitting side transceiver 20 receiving side transceiver

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshinori Mori 3-7-1, 1-cho, Aoba-ku, Sendai, Miyagi Prefecture Tohoku Electric Power Co., Inc. (72) Kanji Yamazaki 3-chome, Obamacho, Amagasaki-shi, Hyogo No. 29-3 Hasegawa Electric Industry Co., Ltd. F-term (reference) 2G014 AA07 AB33 AC07 AC15

Claims (4)

[Claims] 1. A phase detector for judging whether a phase detection target line at two distant points is in phase or out of phase, and detects a ground phase voltage of the phase detection target line at each phase detection point. The transmitting side and receiving side detecting sections for outputting these as phase detection signals, respectively, and the phase detecting signals of the transmitting side detecting section are converted into transmission signals by pulse frequency conversion, and the transmission signals are transmitted to commercially available transmission side transceivers. The transmitting side interface unit and the receiving signal of the commercially available receiving side transceiver are converted into the phase detecting signal of the transmitting side detecting unit by frequency pulse conversion, and the phase detecting signal of the transmitting side detecting unit and the phase detecting of the receiving side detecting unit are converted. A phase detector, comprising: a phase interface for comparing a signal with a signal; and a receiving interface unit for determining and displaying whether the phase detection target line is in phase or out of phase based on the comparison result. 2. The transmitting-side interface unit converts a pulse signal of an audible frequency into a sine wave signal by waveform shaping, and outputs a sine-wave signal of the audible frequency to a phase detection signal of a commercial frequency input from the transmitting-side detecting unit. 2. The phase detector according to claim 1, wherein a transmission signal of the transmission-side transceiver is obtained by adding the following. 3. The receiving-side interface unit converts a received signal of the receiving-side transceiver into a phase-detected signal of a transmitting-side detecting unit by frequency pulse conversion, and based on a phase-detected signal input from the receiving-side detecting unit. By generating a detection pulse signal and comparing the phase of the phase detection signal of the transmitting side detection unit with the detection pulse signal as a criterion, a display output for determining whether the phase is the same or different based on the comparison result is generated. The phase detector according to claim 1, characterized in that: 4. The reception-side interface unit can arbitrarily set a phase detection sensitivity for judging in-phase or out-of-phase by adjusting a rise time of a detection pulse signal as a judgment reference. The phase detector according to claim 3.