JP3330339B2 - Distribution line carrier signal receiving circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase distribution line which is used as a transmission line for a carrier signal, and superimposes a carrier signal modulated by data on a commercial frequency to transmit data. The present invention relates to an improvement of a distribution line carrier signal receiving circuit in a distribution line carrier system that performs control and measurement.

[0002]

2. Description of the Related Art FIG. 4 is a diagram showing a signal injection system and a signal detection system in a conventional distribution line carrier signal transmission circuit and a conventional distribution line transmission circuit.

As shown in FIG. 4 (a), in a conventional distribution line transport system in a three-phase high-voltage distribution line, the transmission side uses a control signal from a communication line to control the three-phase inverter 11 on the transmission side.
To produce a modulated carrier signal, via a three-phase coupler 12, S _U for all phases of the three-phase high voltage distribution line L, S _V,
It was injected as S _W, the receiving side, detection circuit 13 performs detection of the received signal from any one phase among the three phases. FIG. 4 (a)
Then, the received signal is detected from the V phase, and D _{V of the} detection circuit 13 is detected.
It is shown as an example of outputting from between the terminals .about.COM. The detection of the received signal on the receiving side in FIG. 4A is performed by using a PD (potential divider, FIG. 5A) that performs voltage division by a capacitor as shown in various detection circuits in FIG. Although shown, it is also possible to use a star-connected VT (voltage transformer, FIG. 5B) or CT (current transformer, FIG. 5C). Note that the transmission / reception signal vector in this case is, as shown in FIG.
S _U, S _V, S _W is the same amplitude and phase, respectively 120
°, the receiving side can reliably detect a signal from any phase.

The detected reception signal passes only a carrier signal of a required frequency band in the band-pass filter 14, and is again taken out as a data signal S in the detection circuit 15. Incidentally, COM common terminal, the detection terminals, T of V-phase D _V detection circuit 13 of the detection circuit 13 is a transformer substation.

[0005]

In recent years, miniaturization and cost reduction have been demanded for devices such as an inverter (including a modulation function) and a signal coupling circuit used in a distribution line conveying system. Thus, a single-phase line injection method using a single-phase inverter is adopted on the transmission side. FIG. 6 shows an example of a single-phase line injection method. FIG.
FIG. 6A is a diagram illustrating connection of a transmission circuit and a reception circuit of a carrier signal to the three-phase high-voltage distribution line L, and FIG. 6B is a reception signal vector diagram in the single-phase line injection system.

In the case of adopting the single-phase line injection method, since there are a plurality of transmission points of the carrier signal, the injection phase at each transmission point is undefined (in FIG. 6A, the injection phase is injected into the UW phase). Therefore, on the receiving side, detection of only a single phase (FIG. 6)
In (a), a case may occur in which the signal cannot be received by V-phase single-phase detection). Therefore, signals are detected from two phases of the three-phase star connection, and the signal is reliably detected without depending on the phase relationship between transmission and reception. Need to be able to receive. FIG. 6A shows an example in which a signal is detected from the U phase and the W phase. However, in the case of the present method, the case where the received signal is detected in only one of the phases depending on the injected phase and the case where both the two phases are detected occur, so that a receiving circuit is provided for each phase, or , It is necessary to combine and receive two-phase reception signals.

The configuration of the receiving device in the latter case is shown in FIG.
(A) As shown in FIG.
The one-phase received signal among the received signals is sent to the inverting and adding circuit 17.
After adding and combining, the result is bandpass-filled.
Pass only the carrier signal of the required frequency band
After that, the detection circuit 19 captures the data signal S.
System. In FIG. 6A, reference numeral 20 denotes
Single-phase inverter, 21 is a single-phase coupler, COM is a detection circuit
16 common terminals, D_U Is the U-phase detection terminal, _W Is
Similarly, a W-phase detection terminal and T is a transformer of a substation. Ma
The received signal vector has an amplitude as shown in FIG.
The widths are the same and the phases differ by 180 °.

FIG. 7 is a diagram showing a detection state of a received signal in the single-phase line injection system shown in FIG. 6. The relationship between the injection phase on the transmission side and the detection phase on the reception side will be described with reference to FIG. FIG.
For example, as shown in FIG.
In the case where the reception signal is detected from two phases of the U phase and the W phase, assuming that the carrier signal is injected into the UV phase in a single phase on the transmission side, as shown in FIG. Then, S _U (+) is received. Next, assuming that a signal is injected into the VW phase in a single phase on the transmitting side, the receiving side receives _SW (−) as shown in FIG. 7B. Note that S _U
The amplitudes of (+) and _SW (-) are the same. Further, assuming that the carrier signal is injected into the UW phase in a single phase on the transmitting side, the receiving side receives S _U (+) and S _W (−) as shown in FIG. 7C. Here, assuming the case as shown in FIG. 7 (c), when the one-phase detection signal is inverted and added, the two-phase reception is compared with the one-phase reception as shown in FIG. 7 (d). Therefore, a difference is required in the received signal level, so that some correction is required.

As described above, if a detection circuit is provided for each phase, the cost will be relatively high. In addition, when two-phase signals are combined and received, simple signal inversion and combination depend on the number of reception phases. As a result, the level of the received signal is different, which causes inconvenience in designing the dynamic range and measuring the signal level in the distribution line carrier signal receiving circuit. (Object of the Invention) The object of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a distribution line carrier signal receiving circuit of a single-phase line injection system, which is reduced in size without increasing the number of circuits on the receiving side and is not restricted by the phase relationship between transmission and reception.

[0010]

In order to achieve the above-mentioned object, the present invention provides a method for injecting a carrier signal between any one of three-phase distribution lines on a transmitting side and a method for injecting a carrier signal on a receiving side. Detecting a received signal in two phases of the phase distribution line, separating the carrier signal from the detected received signal, a distribution line carrier signal receiving circuit to detect, the detected two-phase received signal Delay the phase of one phase of the received signal by 60 degrees,
The reception signal is synthesized by adding the reception signal to another one-phase reception signal.

[0011]

FIG. 1 is a diagram showing an example of a distribution line carrier signal receiving circuit according to an embodiment of the present invention.

As shown in FIG. 1, in order to detect a carrier signal injected between single-phase lines on the transmitting side of a three-phase high-voltage distribution line L, for example, in a detection circuit 1, two phases of U-phase and W-phase (star detects the reception signal S _U and S _W from the shape connection), the phase of the 60 ° phase of the received signal S _W of the W-phase delay circuit 2
The signal is delayed by 60 ° at the signal center frequency, added to the U-phase reception signal S _U by the addition circuit 3, passed only by the carrier signal of the required frequency band in the band-pass filter 4, Extracted as signal S. Incidentally, COM common terminal, D _U is also detected terminal, D _W of the U-phase of the detection circuit 1 is a detection terminal of the same W-phase.

FIG. 2 is a diagram showing a received signal vector in the distribution line carrier signal receiving circuit configured as shown in FIG.

As shown in FIG. 2A, for the carrier signal injected into the UV phase on the transmitting side, U
The received signal S _U (+) is detected in one phase only, and
As shown in FIG. 2B, with respect to the carrier signal injected into the VW phase on the transmission side, the reception signal SW _W (-) is detected on the reception side only in the W phase, and these phases are detected. But the amplitude is the same.

Next, on the transmitting side, the carrier signal is applied to the WU phase in a single-phase mode.
In the case of receiving, as shown in FIG.
Received signal S in W phase_W (+), Received signal S in U phase_U (-)
Are detected with a 180 ° phase difference. this
If a signal is detected from two of the three phases,
Phase signal S_U The signal S with the phase of (−) delayed by 60 °
_U ′ Is generated and the W-phase signal S_W Addition synthesis to (+)
Then S_W + S_U ′ Is obtained, as shown in FIG.
So, this signal S_W + S_U ’Amplitude in one phase
Only when the signal is received.

FIG. 3 is a diagram showing a composite reception signal in each relationship between the injection phase of the carrier signal on the transmission side and the detection phase of the reception signal on the reception side. As is clear from FIG. The detection of the signal is the same regardless of the phase relationship on the transmitting and receiving sides, that is, the carrier signal injected between the single-phase lines on the three-phase distribution line on the transmitting side, and the receiving signal is detected from the two phases on the receiving side. In the case of a distribution line transport system that can receive a received signal with the same amplitude as the signal level when the received signal is received only from one phase and uses single-phase line injection, a star By detecting a reception signal from any two phases of the connection, a reception signal of the same level can be always received regardless of the phase relationship between transmission and reception.

[0017]

As described above, according to the present invention,
It is possible to provide a distribution line carrier signal receiving circuit that can be downsized without increasing the number of circuits on the receiving side and that is not restricted by the phase relationship between transmission and reception even when the transmitting side is a single-phase line injection system.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a distribution line carrier signal receiving circuit according to an embodiment of the present invention.

FIG. 2 is a diagram showing a received signal vector in the distribution line carrier signal receiving circuit of FIG. 1;

FIG. 3 is a diagram illustrating a combined reception signal in each relationship between an injection phase of a signal on a transmission side and a detection phase of a signal on a reception side.

FIG. 4 is a diagram illustrating a signal injection method and a signal detection method in a conventional distribution line carrier signal transmission circuit and a conventional distribution line transmission circuit.

FIG. 5 is a diagram showing various detection circuits.

FIG. 6 is a diagram showing a conventional example of connection between a transmission circuit and a reception circuit of a carrier signal of a single-phase line injection system to a three-phase distribution line.

FIG. 7 is a diagram showing a received signal detection state in the single-phase line injection method of FIG. 6;

[Explanation of symbols]

Reference Signs List 1 detection circuit 2 60 ° phase delay circuit 3 addition circuit 4 bandpass filter 5 detection circuit 11 three-phase inverter 12 three-phase coupler 13 detection circuit 14 bandpass filter 15 detection circuit 16 detection circuit 17 inverting addition circuit 18 bandpass filter 19 detection Circuit 20 Single-phase inverter 21 Single-phase coupler COM Common terminal of detection circuit D _U- phase detection terminal of _U detection circuit D-phase detection terminal of _{V V} detection circuit D-phase detection terminal of _W detection circuit L Three-phase high-voltage distribution Line S Data signal S _U U-phase reception signal S _U 'U-phase reception signal delayed by 60 ° S _V V-phase reception signal _SW W-phase reception signal T Transformer at substation

Claims (1)

(57) [Claims] 1. A transmitting side injects a carrier signal between any one phase of three-phase distribution lines, and a receiving side detects a reception signal in two phases of the three-phase distribution lines, and detects the signal. A distribution line carrier signal receiving circuit that separates the carrier signal from the received signal and detects the delay, delaying the phase of one phase of the detected two-phase received signal by 60 degrees,
A distribution line carrier signal receiving circuit, wherein the received signal is synthesized by adding the received signal to another one-phase received signal.