JPS61153571A - Phase detection system for distribution line - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for detecting the classification of multi-wire AC power distribution lines.

[Prior art]

Multi-wire AC distribution lines such as 3-phase 3-wire and single-phase 3-wire systems are labeled with phase names such as R, S, and T, and these phase classifications must be clearly identified in power transmission and distribution. In cases where electric wires have been laid as follows, the phase separation may become unclear during distribution line switching work in the event of an accident. In this case, measure the line voltage or ground voltage. Although phase determination has been done empirically based on voltage differences, etc., this has the disadvantage of being inaccurate due to the effects of voltage fluctuations.

[Summary of the invention]

The present invention has the purpose of completely eliminating all the drawbacks of the conventional art, by converting the alternating current waveform of a known specific phase into a full rectangular wave, modulating the entire carrier wave with this, transmitting it through a transmission line, and transmitting it to other parts. This is received and demodulated to obtain a received rectangular wave, and the AC waveform obtained from any phase is used as the entire test rectangular wave, and after compensating for the transmission delay time from modulation to demodulation,
The present invention provides an extremely effective distribution line phase detection method that compares the phases of a received rectangular wave and a tested rectangular wave and detects the phase relationship between a known specific phase and any of the phases.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings of Example Kaneko.

Figure 1 is a block diagram, and Figure 2 is a diagram showing the waveforms of each part in Figure 1, which is a 3-phase, 3-wire arrangement having R(a), 5(b), and T(c) phases. Electric wires 1a to 1C are wired, and at a specific location 2 such as a substation or a business office, a low voltage AC waveform (a) t-obtained from a specific phase, for example, R (a) phase, via a transformer 3, The waveform converter 4 converts this into a rectangular wave (d) with the zero cross point as the changing point, and the modulator 5 converts the rectangular wave (d) into a carrier wave 'tF of high and low image frequencies.
After sK (frequency shift) modulation, the signal is transmitted as No. 4, and is transmitted from an antenna 7 via a transmitter 6 that constitutes the entire wireless transmission line.

On the other hand, in other parts 8 such as work sites along the power distribution lines 1a to 1C, the transmission from the antenna 7 is received by all the antennas 9 and the receiver 10, and the received output is all demodulated by the demodulator 11.
demodulates the received rectangular wave (e) t-obtain, delay circuit 1
2, the transmission delay time from the modulator 5 to the demodulator 11 is compensated by the delay time td, and the reference rectangular wave (f)
shall be.

Also, as one of the phases, for example, a low voltage AC waveform (b) from the 5(b) phase via the transformer 13? This is converted by the waveform converter 14 into a test rectangular wave (9) whose changing point is the zero-crossing point of the AC waveform (b), and this is combined with the reference rectangular wave (f) in an exclusive OR circuit. The phase comparator 15 performs all the phase comparisons between the two, extracts the comparison output (h), and determines its pulse width tp by counting clock pulses in the judgment circuit 16. This result is displayed on the display 1T. It is to be displayed by.

Therefore, in other parts 8, the phase relationship between the known specific phase and any arbitrary phase is detected according to the display on the display 17, and the phase classification of each distribution line 1a to 1C is easily and accurately determined. be able to.

Note that the delay time td of the delay circuit 12 is the antenna 7.9.
Since the transmission time between them can be ignored, it is desirable that the antenna 9 to the display 1γ be integrated into a mobile or portable type and adjusted at the specific location 2.

Further, the carrier wave for performing FSX modulation is required to be selected from the frequencies that pass through all the transmission lines between the transmitter 6 and the receiver 10.

However, the transmission line used may be not only a wireless line but also a wired line, and the frequency of the carrier wave is selected according to these transmission frequency bands, and depending on the situation, in addition to FSK modulation, amplitude modulation, The same applies to devices that perform various modulations such as phase modulation, and the delay circuit 12 is connected to the input side of the demodulator 11, or between the transformer 13 and the phase comparator 15, or between the transformer 3 and the transmitter. It may also be provided between the machines 6.

In addition, the judgment circuit 16 uses an integral circuit isotonous, and the comparison output (h
) After k-averaging, an indicator may be used as the indicator 17 and driven.Alternatively, an indicator that simply generates a discrepancy output may be used as the phase comparator 15, and this output lights up the indicator light. Even if I do the same thing,
The present invention can be applied to single-phase three-wire distribution lines, and various modifications can be made.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to easily and accurately identify the phases of a multi-wire distribution line, so that each phase can be correctly connected and In addition to optimizing the load distribution situation at each stage, construction work can be speeded up, and significant effects can be obtained in terms of phase inspection of distribution lines.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing the corrugated metal of each part in FIG. 1a-1c...Power line, 2...Fist/specific part,
3,13...Transformer, 4,14...Fist...Waveform converter, 5...Modulator, 6-...Transmitter, T,9...
・Antenna, 8...Other parts, 10...Receiver, 11...Demodulator, 12...Delay circuit, 15...
... Phase comparator, (a) to (c) ... AC waveform,
(d)... Rectangular wave, (e)... Received square wave, (
7)...Test square wave, (h)...Comparison output.

Claims (1)

[Claims] The AC waveform obtained from a known specific phase of the multi-wire distribution line is converted into a rectangular wave whose changing point is the zero cross point of the waveform, and the carrier wave of the frequency passing through the transmission line is modulated by the rectangular wave and then transmitted. The transmitted signal is transmitted as a signal through the transmission line, the transmitted signal is received via the transmission line at another part of the distribution line, the reception output is demodulated to obtain a received square wave, and the transmission signal is transmitted at another part of the distribution line. Converting an AC waveform obtained from any phase of the electric wire into a test rectangular wave whose changing point is a zero-crossing point of the waveform, and transmitting the test rectangular wave and the received rectangular wave from the modulation to the demodulation. A distribution line phase detection method characterized by performing phase comparison after compensating for delay time, and detecting the phase relationship between the specific phase and any phase based on the comparison output.