JPH088518B2 - Master station device and slave station device for distribution line transportation - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention uses a distribution line for supplying commercial power as a transmission line for a carrier signal, and carries a signal with a relatively low frequency superimposed on the commercial frequency. According to the above, the present invention relates to an improvement of a master station device and a slave station device for carrying a distribution line, which transmits and receives a monitoring / control signal and a data signal on the distribution line.

(Background of the Invention) A distribution line carrier system in which a line between distribution lines is used as a carrier signal transmission line and a signal is transmitted from a master station device to a slave station device is generally called a ripple control system. It is used to transmit carrier signals for various monitoring and control from distribution systems and load devices.

Further, the distribution line carrying method of sending a signal from the slave station device to the master station device is called a current returning method and is used for collecting data.

 FIG. 6 is an explanatory diagram of a distribution line conveying system.

A command signal from the central device 1 installed in a business office of an electric power company is sent to a substation device 4 installed in a distribution substation having a substation main transformer 3 through a communication line 2, and the substation device is provided. 4 from the transmission circuit 5 through the coupling circuit 6 to be injected into the substation bus 7 as a voltage signal.

The injected signal is carried on the high-voltage distribution line 8 and is received by the slave station device 11 connected to the low-voltage distribution line 10 via the pole transformer 9.

Further, the data of the slave station device 11 is injected as a current signal into the low voltage distribution line 10, and is received by the receiving circuit 14 via the feeder current transformer 12 and the auxiliary current transformer 13 of the substation.

 The central device 1 and the substation device 4 constitute a master station device 15.

In the case of signal transmission from the master station device 15 to the slave station device 11, the distribution line transportation method enables monitoring and control of the entire electrode supply system including the low voltage distribution line by injecting the signal into one substation bus 7 Therefore, this is a very effective method for configuring an automated distribution system, but instead of using a dedicated signal line as a signal transmission line, a distribution line for commercial power supply is used. The fluctuation of the S / N ratio due to the fact that the level of the noise existing at the moment changes momentarily, and the output level of the transmission circuit 5 of the substation device 4 is set to a constant value, the injection point caused by the load fluctuation There is a problem in that the injection level of the signal changes as the impedance changes.

In order to solve these problems, conventionally, the standard injection level of the signal is set to a high level of 1-2% with respect to the commercial frequency voltage, which is a high level with a sufficient margin, and the change of the signal injection level or the noise level is changed. Even if there was, it was able to ensure sufficient reliability.

Therefore, the signal-to-noise ratio during signal transmission can be maintained in a good condition in most applicable fields and load conditions, but on the other hand, from the effect on load equipment distributed in the distribution system,
It is desirable that the signal injection level be as low as possible, which has been a major problem in the distribution line transport system.

(Object of the Invention) A first object of the present invention is to solve the above-mentioned problems, to ensure the reliability of signal transmission, and to reduce the influence on load equipment. It is to provide a master station device for use.

Further, the second object of the present invention, in achieving the above first object, the master station device efficiently data for making the setting of the S / N ratio in the master station device more accurately. It is an object of the present invention to provide a slave station device for carrying a distribution line that enables sending.

(Characteristics of the invention) In order to achieve the first object, the invention according to claim 1 is to transmit a signal to a slave station device between lines of a distribution line, and a signal from the slave station device. In the distribution line carrier master station device having a receiving means for receiving the, the signal injection level at the signal injection point, and a measuring means for measuring the noise level of the signal transmission band, and the S / N ratio at the signal injection point Setting means for setting, and automatic adjusting means for adjusting the signal injection level to match the S / N ratio set by the setting means in accordance with changes in the signal injection level and the noise level measured by the measuring means. And a storage means for storing and updating the noise level measured by the measuring means and the signal injection level of the result adjusted by the automatic adjusting means, thereby providing the S / N ratio at the signal injection point. The preset one In addition to a constant value, the signal injection level is always adjusted to the minimum necessary value, that is, it is adjusted to a large value when there is much noise and a small value when there is little noise. To do.

Further, in order to achieve the second object, the present invention according to claim 2 is a receiving means for receiving a signal sent from the master station device according to claim 1 through a power distribution line, and the master station device. In a distribution line carrier slave station device having a transmitting means for injecting a signal to the terminal, the signal reception level when the signal from the master station device is received and the noise level in the signal transmission band at the signal reception point are measured. Measuring means, and the signal reception level measured by the measuring means, and the S / N ratio calculated from the signal reception level and the noise level, the S / N ratio at the injection point of the signal in the master station device is A transmission control unit that causes the transmission unit to transmit to the master station device is provided in order to grasp the state of the entire transmission system when set.

(Embodiment of the Invention) FIG. 7 is a typical example of frequency versus transmissibility of a signal from a substation bus 7 to an end of a distribution system.

As is clear from FIG. 7, the signal transfer rate is more stable in the lower frequency band, and the noise level on the power distribution line is more uniform in the lower frequency band.

The present invention provides the stability of the signal transfer rate in the low frequency band,
And the uniformity of the noise level, that is,
In the low frequency band, since the signal transfer rate and the noise level are uniform, the S / N ratio at the signal injection point is almost equal to the S / N ratio at the signal reception point. By injecting the minimum necessary level signal according to the noise level at the point, it is possible to always ensure the reliability of signal transmission without injecting an excessive level signal.

FIG. 1 is a block diagram showing a signal injection-related portion of a substation device 20 in a master station device according to an embodiment of the present invention.

FIG. 2 is a flow chart showing the order of operations in the embodiment shown in FIG.

FIG. 3 is a block diagram showing a part related to the S / N ratio setting of the central unit 21 of the master station apparatus which is an embodiment of the present invention.

In this embodiment, the pulse width control method is used as the signal level control method. As a signal level control method,
In addition to this, there are a method of controlling the DC power supply voltage of the inverter by a thyristor, a method of controlling the gain by using an analog amplifier, and the like. In the distribution line carrier method, a commercial frequency and its harmonics are connected via a coupling circuit. Since the leak voltage spills into the transmission circuit, the pulse width control method that can vary the signal level injected into the distribution line while keeping the output voltage of the transmission circuit constant is optimal.

When monitoring and controlling the power distribution system, the main control circuit 22 to the line control circuit 23 of the central unit 21 such as the sales office of the power company
After that, the necessary command signal is issued to the slave station device, but the S / N ratio setting circuit 24 of the central device 21 can set the S / N ratio to any value, and the main control circuit 22 sends the command signal. Prior to doing
The value of the S / N ratio at the signal injection point is transmitted to the substation device 20, and the substation device 20 receives the value at the level adjusting circuit 25. However, the transmission of this S / N ratio is the S / N ratio at the time of the previous signal injection.
It is performed only when the ratio is changed, and omitted when the S / N ratio is not changed.

The level adjustment circuit 25 is
A standard pulse duty is given to the pulse width control circuit 26,
The inverter circuit 27 is driven for a short time with this standard pulse duty.

The output pulse of the inverter circuit 27 is converted into a sine wave having a predetermined signal frequency by a coupling circuit 28, which is an LC resonance circuit including a transformer and a capacitor, and is tentatively injected into the substation bus 7.

In step 2, the level detection filter 29 separates the injected test signal from the commercial frequency through the transformer 30, the A / D converter 31 digitizes the test signal, and the level measurement circuit 32 measures the signal injection level. . Level adjustment circuit 25
In step 3, the level storage circuit 33 stores the measured signal injection level and the pulse duty used at that time.

Next, in step 4, the level detection filter 29 separates the noise of the substation bus 7 which is the signal injection point from the commercial frequency, and
The D converter 31 digitizes the noise, the level measuring circuit 32 measures the level, and in step 5, stores the result in the level storage circuit 33. Send command (step 6)
And S / N ratio data (step 7) are both stored in the central unit 2
When not sent from 1, noise level measurement and data storage are always performed.

When the S / N ratio data is sent from the central unit 21 prior to the transmission command, the process proceeds from step 7 to step 8,
The level adjustment circuit 25 determines the pulse duty of the pulse width control signal corresponding to the signal injection level that is the S / N ratio set by the central unit 21 with respect to the measured noise level, based on the data of the level storage circuit 33. Calculate and pulse width control circuit
Transfer to 26.

When the pulse width control circuit 26 receives the command signal from the central device 21 in step 6, the pulse width control circuit 26 controls the inverter circuit 27 by the pulse width control signal of the pulse duty corresponding to the signal injection level which is the S / N ratio set previously. In control, the inverter circuit 27 injects a voltage signal into the substation bus 7 at a predetermined level via the coupling circuit 28.

Further, in step 10, the level measurement circuit 32 measures the signal injection level immediately after the signal injection is started, and the step 11
In the case where the S / N ratio at the injection point is different from the preset value, in step 12, the signal injection level is repeatedly corrected until the predetermined S / N ratio is obtained, and in step 13 Then, the data in the level storage circuit 33 is updated with the pulse duty of the pulse width control signal corresponding to the finally corrected signal injection level, and is used as the data for calculating the pulse duty for the next signal transmission.

Further, the level adjusting circuit 25 returns the data of the signal injection level to the central device 21 in step 15 after the signal injection is completed (step 14), and displays it on the operation panel of the central device 21 for operation. Allow the person to confirm this.

As the value of the S / N ratio to be set, it is usually enough to set it to about 20 dB, and the signal injection level for this is
Since it is 0.1 to 0.2% of the commercial frequency voltage, the signal injection level is about 1/10 of the conventional level, and the effect on load equipment is greatly reduced.

 Note that steps 1 to 3 are not always necessary.

The distribution company's remote monitoring and control functions performed by electric power companies include automatic meter reading data for electricity meters, control of distribution system switches, collection of distribution line management information such as distribution line voltage and current, and load control. However, in the case of load control that does not require the return of the data signal from the slave station device 11 among these functions, the load control receiver is installed at the low voltage end of the distribution system, and Since it is difficult to predict the reliability of the receiving side from the S / N ratio, and the reception status cannot be confirmed, it is not possible to set any S / N ratio and it is set in advance in the level adjustment circuit 25. The signal is injected at a high level where a sufficient S / N ratio similar to the conventional one can be expected, and the signal level is not adjusted.

Further, in the case of automatic meter reading, switch control, and power distribution management information collection, different S / N ratios are desirable because the time zones and frequencies are different.

Next, not only the master station device but also a slave station device having a function of returning a data signal to the master station device measures the signal level transmitted from the master station device and the noise level at the signal reception point. A distribution line carrying slave station device will be described in which means is provided and the signal reception state is returned to the master station device.

FIG. 4 is a block diagram of a distribution line carrying slave station device 40 which is an embodiment of the present invention.

FIG. 5 is a flowchart showing the sequence of operations of the slave station device 40.

In the slave station device 40, in step 20, the noise on the low-voltage distribution line 10 is separated from the commercial frequency by the reception filter 41, the A / D converter 42 converts it into a digital value, and the level measurement circuit 43 constantly maintains the level. The measurement is performed, and in step 21, the level storage circuit 44 stores this data.

In step 22, when the receiving circuit 45 detects that there is a signal,
In step 23, the level measuring circuit 43 measures the signal level, in step 24 the S / N ratio for the signal level and noise level is calculated, and in step 25, the level storage circuit 44
Store these data in. When the receiving circuit 45 determines in step 26 that the received signal is its own calling command signal, it receives the command content in step 27. The load monitoring control circuit 46 operates according to the received command content, and inputs data such as a monitoring result to the transmission control circuit 47. Further, the level measuring circuit 43 reads out the signal level and the S / N ratio from the level storage circuit 44 and inputs them to the transmission control circuit 47. As a result, in step 28, the transmission circuit 48 returns the signal level and S / N ratio to the parent station device by adding it to the returned data.

In the master station device, the noise level at the signal injection point and
The state of the entire transmission system can be grasped together with the S / N ratio data, and therefore the S / N ratio can be set more accurately.

In addition, when the data related to the signal reception state is always added to the return data and the slave station device 40 returns the data to the master station device, the returned data becomes redundant and the operability of the distribution system automation system is impaired. May add an instruction bit to the command from the master station device to the slave station device 40, and may return data as necessary.

(Correspondence between Invention and Embodiment) The inverter circuit 27 and the coupling circuit 28 shown in FIG.
The level measuring circuit 32 in FIG. 1 is the measuring means, the S / N ratio setting circuit 24 in FIG. 2 is the setting means, and the level adjusting circuit 25 in FIG. 1 is the automatic adjusting means. The level storage circuit 33 of FIG. 1 corresponds to the storage means.

Further, the reception filter 41 and the reception circuit 45 of FIG. 4 correspond to the reception means of the invention described in claim 2, the level measurement circuit 43 of FIG. 4 is the measurement means, and the transmission control circuit 47 is the transmission control means. Equivalent to each.

(Effects of the Invention) As described above, according to the present invention as set forth in claim 1, the signal injection level at the signal injection point and the noise level in the signal transmission band are measured in the master station device for carrying the distribution line. Measuring means, setting means for setting the S / N ratio at the injection point of the signal, and the signal injection level was set by the setting means according to the change in the signal injection level and the noise level measured by the measuring means. An automatic adjusting means for adjusting to match the S / N ratio, and a memory means for storing and updating the noise level measured by the measuring means and the signal injection level of the result adjusted by the automatic adjusting means are provided, Therefore, the S / N ratio at the injection point of the signal is set to a preset constant value, and the signal injection level is always adjusted to the minimum necessary value, that is, a large value when there is a lot of noise,
When the noise is small, the value is adjusted to a small value, so it is possible to ensure the reliability of signal transmission.
The influence on the load device can be reduced. Also, measure the signal injection level and noise level at the signal injection point,
The signal injection level is adjusted according to the change, and since this adjustment is independent of the response of the slave station device, the adjustment to the predetermined signal injection level can be performed in a short time. Furthermore, since the signal injection level is stored and updated by the storage means as the adjustment result, the operation of the automatic adjustment means can be facilitated.

According to the present invention as set forth in claim 2, a signal reception level at the time of receiving a signal from the master station device according to claim 1 to the distribution line carrier slave station device, and signal transmission at a signal reception point. Measuring means for measuring the noise level of the band, the signal reception level measured by the measuring means, and the S / N ratio calculated from the signal reception level and the noise level, the signal injection point at the master station device. In order to grasp the state of the entire transmission system when the S / N ratio is set, the transmission means is provided to the master station device by the transmission means, so the S / N ratio in the master station device is set. It is possible to efficiently send data to the master station device so that the setting can be performed more accurately.

[Brief description of drawings]

FIG. 1 is a block diagram showing a signal injection-related portion of a substation device which constitutes a part of a distribution line carrier master station device according to an embodiment of the present invention, and FIG. 2 is a signal of the embodiment shown in FIG. FIG. 3 is a flow chart showing the sequence of the injection operation, and FIG. 3 is a block diagram showing the S / N ratio setting-related portion of the central device which constitutes the remaining part of the distribution line carrier master station device according to an embodiment of the present invention, Fourth
FIG. 5 is a block diagram showing a slave station apparatus for carrying a distribution line according to an embodiment of the present invention, FIG. 5 is a flow chart showing the sequence of operations of the embodiment shown in FIG. 4, and FIG. 6 is a conventional distribution line carrying system. FIG. 7 is a diagram showing the frequency vs. transmissibility characteristic of the signal of the high voltage power distribution line. 1 ... Central device, 4 ... Substation device, 11 ... Slave station device,
15 …… Main station equipment, 20 …… Substation equipment, 21 …… Central equipment,
24 …… S / N ratio setting circuit, 25 …… Level adjustment circuit, 26 ……
Pulse width control circuit, 27 …… Inverter circuit, 29 …… Coupling circuit, 29 …… Level detection filter, 31 …… A / D converter, 32 …… Level measurement circuit, 33 …… Level storage circuit, 40
...... Slave station device, 41 …… Reception filter, 42 …… A / D converter, 43 …… Level measurement circuit, 44 …… Level storage circuit,
45 …… Reception circuit, 46 …… Load monitoring control circuit, 47 …… Transmission control circuit, 48 …… Transmission circuit.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masahiro Oikawa 3-7-1, Ichibancho, Sendai City, Miyagi Prefecture Tohoku Electric Power Co., Inc. (72) Inventor Satoshi Komazawa 2-2-7, Higashigotanda, Shinagawa-ku, Tokyo Osaki Electric Industry Co., Ltd. (72) Inventor Kyoichi Koyama 2-2-7 Higashigotanda, Shinagawa-ku, Tokyo Osaki Electric Industry Co., Ltd. (56) Reference JP-A-63-151122 (JP, A) JP-A-51-21415 (JP, A) JP-A-56-48735 (JP, A) Actually opened 61-42152 (JP, U) Actually opened 53-88742 (JP, U)

Claims (2)

[Claims] 1. A master station apparatus for carrying a distribution line, comprising: a transmitting means for injecting a signal to a slave station apparatus between lines of a distribution line; and a receiving means for receiving a signal from the slave station apparatus. Measuring means for measuring the signal injection level at the injection point and the noise level in the signal transmission band, and S / at the signal injection point
Setting means for setting the N ratio, and automatic adjustment for adjusting the signal injection level to match the S / N ratio set by the setting means in response to changes in the signal injection level and the noise level measured by the measuring means. A master station for distribution line delivery, comprising: adjusting means; and storage means for storing / updating the noise level measured by the measuring means and the signal injection level as a result of the adjustment by the automatic adjusting means. apparatus. 2. A distribution line carrying slave station comprising a receiving means for receiving a signal sent from the master station apparatus according to claim 1 through a power distribution line, and a transmitting means for injecting a signal to the master station apparatus. In the device, a signal receiving level when a signal from the master station device is received, and a measuring unit that measures a noise level of a signal transmission band at a signal receiving point, and a signal receiving level measured by the measuring unit, and S / N ratio calculated from the signal reception level and the noise level, in order to grasp the state of the entire transmission system when the S / N ratio at the injection point of the signal is set in the master station device, A slave station apparatus for carrying a distribution line, comprising: a transmission control section that causes a transmission section to transmit to the master station apparatus.