JPS61136327A - Signal coupling system for low voltage distribution line communication equipment - Google Patents

Abstract

PURPOSE:To secure a stable transmission line which is scarcely influenced by a load variation by inserting a circuit which goes to a high impedance and a low impedance by a commercial frequency and a signal frequency, respectively, in parallel to both a power source supply end and the last load end of a low voltage distribution line. CONSTITUTION:A bypass capacitor 12 is inserted in parallel to a transformer 11 to the vicinity of a commercial transformer 11 of a commercial power source supply side of a low voltage distribution line 1, and also a bypass capacitor 13 is inserted into the last load side. These capacitors 12, 13 select a capacity value which goes to a lower impedance and a higher impedance by a use frequency and a commercial frequency, respectively, than an impedance of a load 10 connected to the low voltage distribution line 1. In such a way, a transmission line impedance by a signal frequency always goes to low, and a variation by on-and-off conditions of the load goes to small. Accordingly, most of signals from a current transformer 14 flow through a closed loop of the low voltage distribution line 1 and the capacitors 12, 13, and can be extracted by a current transformer 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The industrial field of application 18+1 relates to a signal coupling force formula for a communication device that uses a low-voltage power distribution line as a transmission path.

BACKGROUND OF THE INVENTION Conventionally, this type of communication equipment has adopted a line-to-line coupling force type in which signals are injected in parallel into low-voltage distribution lines using coupling capacitors and coupling transformers as shown in FIG.

By the way, the high frequency physical impedance of the pressure distribution line is
In the range of 10Kth to 4501Gh, the impedance is generally as low as 100 to several ΩO. Also, the fluctuations are large.

However, the length changes quickly and instantaneously depending on the condition of the O load such as the cooler and motor.

In order to fully accommodate these characteristics, the conventional method
A pilot signal for monitoring loss fluctuation levels and a complicated automatic gain 1lin circuit were required on the receiving side. In addition, there is a possibility that the signal may leak to other systems outside the area of use, and to prevent this it is necessary to insert a coil in series with the low-voltage distribution line, which also poses problems in terms of construction.

FIG. 2 is a block diagram of a signal coupling force type of a conventional low voltage distribution line communication device.

In the second vl, l is a low-voltage distribution line (6j), and 2 is a signal transmitter. 3 is a transmission amplifier, which has the function of amplifying the signal generated by the signal transmitter 2 to a level that can be received by the opposing device via the low-voltage power distribution ml. A coupling transformer for 4-digit impedance conversion, also used as insulation from h9 and ° lines. 5 is a coupling capacitor that cuts the commercial voltage, and p1 has an impedance sufficiently high for the commercial station wave number and low for the signal frequency.

A coupling capacitor 6 cuts off the commercial voltage of the signal from the low-voltage distribution line 1, the signal frequency is input to a coupling transformer 7, and a receiving amplifier 8 amplifies the received signal.

This output is restored by the signal receiver 9 as a signal for fulfilling the purpose corresponding to the transmitted signal.

Problems to be Solved by the Invention In the conventional signal coupling force method as described above, a sufficient automatic gain adjustment circuit is required for the above-mentioned receiving amplifier 8, and low voltage distribution is required to prevent signal leakage to other systems. It becomes necessary to insert a coil between the electric wire l and the commercial transformer 11.

Further, the coupling transformer 4.7 and the coupling content t5.6 must be expensive for the purpose of insulation.

Furthermore, the ``ON'' and ``OF'' loads of coolers and baskets
There was a drawback that impedance characteristics and loss characteristics varied depending on the "F" state, making it impossible to secure a high-quality line.

The present invention has been developed in consideration of the above-mentioned conventional circumstances.
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a new signal coupling force formula for a low voltage distribution line communication device that eliminates the above-mentioned Z51 drawbacks.

Means for Solving the Problems In order to achieve the above object, the signal coupling force formula according to the present invention has a high impedance system at the commercial frequency at both the power supply end and the final load end of the low voltage distribution line. Moreover, it is constructed by inserting in parallel a circuit that has a circular impedance at the signal frequency, and connecting a signal injection transformer having the low voltage distribution edge as a secondary side in series with the low voltage distribution line.

Embodiment of the Invention Hereinafter, a preferred embodiment of the signal coupling force formula of the low voltage distribution line communication device according to the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a signal coupling force type of a low voltage distribution line communication device according to the present invention.

A signal generated by the signal transmitter 2 is amplified by a transmission amplifier 3 to a level that can be received at the opposite location via the low voltage distribution line 1. The current transformer 14 injects the amplified signal into the low voltage distribution line 1. The current transformer 15 extracts the signal on the low-voltage distribution line l, the receiving amplifier 8 amplifies the extracted signal, the output is converted to xp, and the signal receiver 9 restores it as a signal for fulfilling the purpose corresponding to the transmitted signal. Sanru.

Here, 14.15 current transformers are used to insulate the low-voltage distribution line and the equipment, and have a number ratio of l:fl to inject and extract signals from the low-voltage distribution line. Here, 1 means the number of turns is 1. This is a low-voltage distribution line that can be thought of as a turn.

In the low voltage power distribution i11, a bypass capacitor 12 and a bypass capacitor 13 are inserted in parallel with the commercial transformer 11 near the commercial transformer 110 on the commercial power supply side. Bypass capacitor 12
．． 13, the impedance of the load connected to 1 ml of W4 low-voltage power distribution is selected to have a capacitance value that provides low impedance at the operating frequency and high impedance at the commercial frequency.

In this way, the transmission path impedance at the signal frequency is always kept low, and fluctuations due to load 1ON'' and OFF conditions are reduced.

Therefore, most of the signal from the current transformer 14 flows through the closed loop of the low voltage distribution line 11 bypass ring 12.13 and is extracted at the current transformer 15.

As described in detail, the present invention provides a low-impedance transmission line, so it is possible to ensure a stable transmission line that is less affected by load fluctuations connected to low-voltage distribution lines, and No. 1 leakage to the grid can be reduced.

In order to make the transmission line low impedance; υ, a current transformer with high signal transmission efficiency between the device and the transmission line can be used. Because current transformers are loosely coupled to transmission lines, they are superior in terms of insulation between low-voltage distribution lines and equipment. It is also possible to connect a capacitor to the current transformer to provide loose coupling for commercial frequencies and tight coupling for signal frequencies.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
The figure is a block diagram showing a conventional example.

Claims (1)

[Claims] In a low-voltage distribution line communication device, a circuit that has high impedance at the commercial frequency and low impedance at the signal frequency is inserted in parallel between the power supply end and the final load end of the low-voltage distribution line. A signal coupling system for a low voltage distribution line communication device, characterized in that a signal injection transformer serving as a next side is connected in series to the low voltage distribution line.