JP7363442B2 - Power line transport control system - Google Patents

Description

The present invention relates to a system for remotely controlling a power line carrier.

BACKGROUND ART Conventionally, power line carrier devices/power line carrier communication devices that perform communication using power lines as transmission paths are known (for example, see Patent Document 1).

Japanese Patent Application Publication No. 2002-111553

By the way, regarding power line transportation, the earth return method is used by the work ground (also called "Otsu earth" or "Otsu class earth") that is attached to field equipment during power line work, and if it falls under the earth return method, It is necessary to apply for high frequency use based on Article 100 of the Radio Law and obtain permission from the Ministry of Internal Affairs and Communications. Therefore, in order to avoid the return-to-ground method, it is necessary to stop the power line transport device before carrying out work on the power line.

When dealing with outages of power line carrier equipment, workers go to the site where the power line carrier equipment is installed and physically disconnect the communication lines. There is a problem of large (in other words, large human and time losses). In addition, it is difficult to deal with outage of power line carrier equipment because it is difficult to deal with daily power outage work over a long period of time when power line work is carried out, and it is necessary to stop communication lines for a long period of time. There is a problem in that the risk of simultaneous outage of two routes, such as lines for remote monitoring and control equipment, increases in the event of a disaster.

Therefore, an object of the present invention is to provide a power line transport control system that can detect the installation of a work ground and stop the power line transport device by remote control without going to the site. .

In order to solve the above problem, the invention of claim 1 provides a reception level monitoring device that detects the reception level in a power line carrier terminal device, and a switching between execution and cutoff of power supply to the power line carrier terminal device. and a remote control device that receives the reception level detected by the reception level monitoring device and transmits a control signal for switching the power supply to the power supply control device. , when the reception level decreases by a predetermined width, the remote control device transmits a control signal for cutting off the power supply to the power supply control device, and the power supply control device receives the control signal. The power line carrier control system is characterized in that the power line carrier control system operates and the power supply to the power line carrier end station device is cut off.

The invention according to claim 2 is the power line carrier control system according to claim 1, comprising an input/output isolated DC-DC converter and a relay circuit connected to the power supply control device, is connected to a power source via the DC-DC converter, the power line carrier end station device is connected to the power source via a relay contact of the relay circuit, and the power source control device receives the control signal. is characterized in that the power supply to the power line carrier end station device is cut off by cutting off the power supply to the relay circuit and opening the relay contact.

The invention according to claim 3 is the power line transport control system according to claim 1 or 2, characterized in that the predetermined width is 1 to 5 dBm.

According to a fourth aspect of the present invention, in the power line carrier control system according to any one of the first to third aspects, the power supply control device is a negative grounding device, and the power line carrier end station device is a positive grounding device.

According to the invention of claim 1, it is possible to detect that a working ground is attached to field equipment based on a specific change in the reception level at a power line carrier end station device without going to the field. In addition, it is possible to stop the power line carrier end station equipment by remote control based on the detection, and it becomes possible to improve labor productivity related to the operation and management of the power line carrier equipment.

According to the invention of claim 2, an input/output isolated DC-DC converter is interposed between the power supply and the power supply control device, and a relay contact is interposed between the power supply and the power line carrier end station device. , it is possible to control the power supply to the power line carrier end station equipment without directly connecting the power control equipment and the power line carrier end office equipment, and the power line It becomes possible to configure a mechanism for controlling power supply to the carrier terminal device.

According to the third aspect of the invention, it is possible to accurately detect that a working ground is attached to field equipment.

According to the invention of claim 4, it is possible to configure a mechanism for controlling the power supply to the power line carrier end station device by using the power control device with negative grounding and the power line carrier end station device with positive grounding. .

1 is a schematic configuration diagram of a power line transport control system according to an embodiment of the present invention. 2 is a configuration diagram of the power line transport control system of FIG. 1. FIG. 2 is a schematic configuration block diagram of a remote control device of the power line transport control system of FIG. 1. FIG. FIG. 3 is a diagram illustrating an example of the reception level at the power line carrier end station device during normal times (when a working ground is not installed on the power transmission line). FIG. 6 is a diagram illustrating an example of a change in reception level at a power line carrier end station device when a working ground is installed at one location on a power transmission line. FIG. 3 is a diagram illustrating an example of changes in reception level at a power line carrier end station device when a fault occurs in a power transmission line. FIG. 3 is a diagram illustrating a schematic configuration of a circuit related to a power supply control device in a case where the power line carrier end station device is connected to a positive ground and the power control device is connected to a negative ground. 2 is a timing chart showing the operation of the power line transport control system of FIG. 1. FIG.

The present invention will be described below based on the illustrated embodiments.

FIG. 1 is a schematic configuration diagram of a power line transport control system 1 according to an embodiment of the present invention. This power line carrier control system 1 is a system that remotely controls a power line carrier device that performs communication using a power line as a transmission path. In this embodiment, a power transmission line 11 and a power transmission line 12 are arranged between an electric station 10A and an electric station 10B, and the power transmission lines 11 and 12 are used as transmission lines for power line transport.

The power line carrier control system 1 includes a reception level monitoring device 2 that acquires the reception level of the power line carrier end station device 13, and a power line control system 1 installed in each of the electric station 10A and the electric station 10B. It has a power supply control device 3 that controls the power supply to the carrier terminal device 13, and is installed in a remote location away from each electric station 10A, 10B, based on information provided from the reception level monitoring device 2. The power supply control device 4 has a remote control device 4 that remotely controls the power supply control device 3.

The reception level monitoring device 2, the power supply control device 3, and the remote control device 4 are each equipped with a communication function. The device 4 is configured to be able to freely communicate with the device 4. In this embodiment, the reception level monitoring device 2, the power supply control device 3, and the remote control device 4 are configured to be able to communicate freely via a communication network 20 such as the Internet or an intranet (for example, a local IP network). configured.

The power line transport control system 1 has a characteristic configuration mainly including a reception level monitoring device 2, a power supply control device 3, and a remote control device 4, and the mechanism itself for performing power line transport has the same configuration as the conventional power line transport. Although a detailed explanation of the configuration equivalent to the conventional one will be omitted, the configuration of this embodiment is roughly as follows (see FIG. 2).

Each power transmission line 11, 12 (specifically, the neutral line of the single-phase three-wire system drop-in line; indicated as "white phase" in the figure) is drawn into each electric station 10A, 10B and connected. It is connected to the power line carrier end station device 13 via a capacitor 15, a line coupling filter (EF) 16, and a balanced coupling filter (MF) 17 for metal circuits, and further via a power line carrier safety device 18. Each power transmission line 11, 12 is also connected to substation equipment via a line trap 19.

The power line carrier terminal device 13 is a device that functions as a terminal station in a power line carrier that performs communication using the power transmission lines 11 and 12 as a transmission path.

The communication power supply 14 is equipment that supplies power to the power line carrier terminal device 13, and is, for example, a DC distribution board.

The power line carrier control system 1 of this embodiment includes a reception level monitoring device 2 that detects the reception level at the power line carrier terminal device 13, and a switch between execution and cutoff of power supply to the power line carrier terminal device 13. and a remote control device 4 that receives the reception level detected by the reception level monitoring device 2 and transmits a control signal for switching the power supply to the power supply control device 3. Then, when the reception level decreases within a predetermined width, the remote control device 4 transmits a control signal (cutoff signal) to cut off the power supply to the power supply control device 3, and the control signal (cutoff signal) The power supply control device 3 that receives this operates to cut off the power supply to the power line carrier terminal device 13.

The reception level monitoring device 2 collects the reception level of the power line carrier end station device 13 and provides it to the remote control device 4 . In this embodiment, the reception level monitoring device 2 detects the reception level at the power line carrier terminal device 13 of the signal superimposed and transmitted on the power transmission lines 11 and 12, and detects the reception level data (reception level) of the detected reception level. A signal representing the level) is transmitted to the remote control device 4 via the communication network 20.

The power supply control device 3 is a device that is interposed between the communication power source 14 and the power line carrier terminal device 13 and switches between execution and cutoff of power supply from the communication power source 14 to the power line carrier terminal device 13. It is.

The remote control device 4 monitors the state of the reception level at the power line carrier end station device 13 using the information provided by the reception level monitoring device 2, detects a change in the reception level, and transmits information to the power line carrier end station device 13. This is a device that executes processing related to determining whether to cut off power supply, and also executes processing related to remote control of the power supply control device 3 based on the result of the determination. As shown in FIG. 3, the remote control device 4 mainly includes a data receiving section 41, a command transmitting section 42, a display section 43, an input section 44, a memory 45, a main task 46, and controls etc. A central processing unit 47 is provided.

The central processing unit 47 is configured, for example, by a processor using a CPU or the like, or configured to implement each function according to a program stored in the memory 45.

The data receiving unit 41 receives data on the reception level (a signal representing the reception level) at the power line carrier end station device 13 transmitted from the reception level monitoring device 2 via the communication network 20 . The data receiving unit 41 transfers the received data at the reception level to the main task 46 .

The command transmitter 42 transmits a control signal transferred from the main task 46 to the power supply control device 3 for cutting off or restarting the power supply from the communication power supply 14 to the power line carrier terminal device 13. It is transmitted via the network 20.

The display unit 43 is, for example, a liquid crystal screen, and displays information regarding the status of the power transmission lines 11 and 12, and the like.

The input unit 44 is, for example, a keyboard or a mouse, and receives operations from a worker and transfers operation signals to the central processing unit 47 and the main task 46.

The memory 45 is a storage device capable of storing various information and data, and functions as a storage area for data such as the reception level received by the data reception unit 41, and is used for determining the operation of the power supply control device 3 and for remote control. It functions as a work area when executing related processes.

The main task 46 is a group of tasks and programs for executing processing related to determination of the operation of the power supply control device 3 and remote control. The main task 46 mainly includes a reception level determination task 46a, a cutoff signal generation task 46b, an alarm output task 46c, and a restart signal generation task 46d.

The reception level determination task 46a is a task that executes a process of determining whether or not a working ground has been installed for the power transmission lines 11 and 12 based on reception level data transmitted from the reception level monitoring device 2.・It is a program. The reception level determination task 46a receives and processes the reception level data transferred from the data reception unit 41, and when it is determined that the work ground has been installed, the reception level determination task 46a transmits the determination result to the cutoff signal generation task. 46b.

In normal times, in other words, when a working ground is not installed for the power transmission lines 11 and 12, as shown in FIG. , the reception level at the power line carrier end station device 13 is stabilized at about -20 dBm. On the other hand, according to the inventor's findings, when a working ground is installed at one location on the power transmission lines 11 and 12, the signal is superimposed and transmitted on the power transmission line 11, as shown in FIG. The reception level at the power line carrier end station device 13 decreases by about 3 dBm, resulting in about -23 dBm, and while the working ground is installed, the reception level stabilizes at about -23 dBm.

Therefore, the reception level determination task 46a determines that a working ground has been installed for the power transmission lines 11 and 12 when the degree of decrease in the reception level at the power line carrier end station device 13 is within a predetermined range. . In addition, when the work ground is installed in two places, the reception level will further decrease by about 3 dBm from the stable state of about -23 dBm when it is installed in one place, resulting in about -26 dBm. As long as the working ground is installed at two locations, the reception level will be stable at around -26 dBm.

At the power line carrier end station device 13, the degree of the reception level in normal times and the degree of decrease in the reception level when a work ground is installed depend on the characteristics of the equipment related to power transmission and distribution, and the equipment related to power line carrier communication. It is conceivable that the present invention is not limited to the above example, depending on the characteristics of the work ground and the degree of influence on various equipment when the work ground is installed. For this reason, the degree of reduction in the reception level especially when the working ground is installed is the same as the reception level actually observed at each power line carrier end station device 13 when the working ground is installed. The values may be set for each power line carrier end station device 13 based on the track record of the degree of decline. The degree to which the reception level decreases (a predetermined width or a predetermined value) when a working ground is installed for the power transmission lines 11 and 12 is referred to as a "ground installation decrease level."

In addition, when a failure occurs in the power transmission lines 11 and 12 due to a lightning strike, for example, as shown in FIG. Specifically, for example, it decreases by about 40 dBm to about -60 dBm (or decreases by 40 dBm or more to -60 dBm or less). Therefore, the reception level determination task 46a determines that if the degree of decrease in the reception level at the power line carrier end station device 13 is within a predetermined width, a working ground is installed for the power transmission lines 11 and 12. If the width exceeds a predetermined width, it is determined that a fault has occurred in the power transmission lines 11 and 12.

The degree of decrease in the reception level when a failure occurs in the power transmission lines 11 and 12 is based on the actual results of the degree of decrease in the reception level actually observed at each power line carrier end station device 13 when a failure occurs. It may be configured to be set for each power line carrier terminal device 13. The degree of reduction in the reception level (predetermined width or predetermined value) when a fault occurs in the power transmission lines 11, 12 is referred to as a "failure occurrence reduction level."

Based on the inventor's knowledge and the above, the reception level determination task 46a performs a work operation on the power transmission lines 11 and 12 when the reception level at the power line carrier end station device 13 decreases within a range of about 1 to 5 dBm, for example. It is determined that a grounding ground has been installed, or it is determined that a working grounding ground has been installed when the reception level drops within a range of about 2 to 4 dBm, or when the reception level drops by about 3 dBm. It is preferable to determine that a work ground has been installed when the work ground is installed.

Then, the reception level determination task 46a analyzes the reception level data transmitted from the reception level monitoring device 2 and transferred from the data receiving unit 41, and determines whether the reception level at the power line carrier end station device 13 is at the earth installation lower level. When a drop corresponding to 1 is detected, an instruction to create a signal to cut off the power supply to the power line carrier terminal device 13 (referred to as a "cutoff signal generation instruction") is transferred to the cutoff signal generation task 46b. The reception level determination task 46a also transfers a cutoff signal generation instruction to the alarm output task 46c.

On the other hand, the reception level determination task 46a does not transfer the cutoff signal generation instruction when the reception level at the power line carrier end station device 13 has decreased to a level that does not correspond to the earth installation decrease level.

The cutoff signal generation task 46b is a task program that executes processing to generate a signal for remotely controlling the power supply control device 3 based on the instruction transferred from the reception level determination task 46a. The cutoff signal generation task 46b starts processing upon receiving the input of the cutoff signal generation instruction transferred from the reception level determination task 46a, and remotely cuts off the power supply from the power supply control device 3 to the power line carrier terminal device 13. A signal (referred to as a "cutoff signal") for this purpose is generated and transmitted to the command transmitter 42.

The alarm output task 46c is a task program that executes a process of outputting information regarding the status of the power transmission lines 11 and 12 based on instructions transferred from the reception level determination task 46a. The alarm output task 46c starts processing upon receiving the input of the cutoff signal generation instruction transferred from the reception level determination task 46a, and outputs information indicating that the working ground has been installed for the power transmission lines 11 and 12. Output. The alarm output task 46c may, for example, cause the display unit 43 of the remote control device 4 to display a message indicating that the working ground has been installed, or the alarm output task 46c may cause the display unit 43 of the remote control device 4 to display a message indicating that the working ground has been installed, or the alarm output task 46c may display a message from a speaker (not shown) of the remote control device 4. make a sound.

The restart signal generation task 46d is a task program that executes a process of generating a signal for remotely controlling the power supply control device 3 based on an instruction given via the input unit 44. The restart signal generation task 46d starts processing upon receiving the input of an instruction given by the operator's operation of the input unit 44, and restarts the power supply from the power supply control device 3 to the power line carrier terminal device 13 by remote control. A signal for this purpose (referred to as a "resume signal") is generated and transmitted to the command transmitter 42.

Here, as a mechanism for switching between execution and cutoff of power supply to the power line carrier terminal device 13, the power supply control device 3 may be directly connected to the power line carrier terminal device 13 as it is; 13 is a positive ground, but if the equipment (also called a "rebooter" etc.) that constitutes the main part of the power supply control device 3 is a negative ground, the power supply control device 3 can be directly connected to the power line carrier terminal device 13. Cannot connect directly. In order to solve this problem, in other words, when the power line carrier terminal equipment 13 is positively grounded and the equipment that constitutes the main part of the power supply control device 3 is negatively grounded, the circuit related to the power supply control device 3 is A schematic configuration is shown in FIG. In the configuration shown in FIG. 7, the power supply control device 3 is connected to negative ground, and the power line carrier end station device 13 is connected to positive ground.

The configuration shown in FIG. 7 includes an input/output isolated DC-DC converter 7 and a relay circuit 9 connected to the power supply control device 3. The power line carrier terminal device 13 is connected to the power source (distribution board 5) via the relay contact 91 of the relay circuit 9, and receives a control signal (cutoff signal). The power supply control device 3 cuts off the power supply to the relay circuit 9 and the relay contact 91 becomes open, thereby cutting off the power supply to the power line carrier terminal device 13.

The distribution board 5 is equipment corresponding to the communication power supply 14 in FIGS. 1 and 2, and is connected to the power supply side terminal 6 to supply DC-48V (DC-24V is also conceivable) DC power. This is a DC distribution board that provides branch supply. Note that the polarity of the power supplied from the distribution board 5 is positive ground.

The DC-DC converter 7 is an input/output isolated type DC-DC converter, and can provide insulation resistance. Therefore, by interposing the DC-DC converter 7 between the distribution board 5 and the power supply control device 3, it is possible to connect the distribution panel 5 and the power supply control device 3, which are devices with different polarity grounding. (In other words, it makes it possible to convert the polarity. In other words, it makes it possible to resolve differences in the polarity of devices.) In the example shown in FIG. 7, the DC-DC converter 7 converts 48V DC to 24V DC (100W) (or, if the distribution board 5 is DC-24V, converts 24V DC to 24V DC ( 50W). Note that the reference numeral 22 in FIG. 7 is a fuse.

The power line carrier end station device 13 is connected to the device side terminal 8 which is connected to the power source side terminal 6 to which power is supplied from the distribution board 5, that is, the power line carrier end station device 13 is connected to the device side terminal 8 which is connected to the power source side terminal 6 and the device side terminal from the distribution board 5. Electric power is supplied via 8. Note that the polarity of the power supply supplied from the distribution board 5 is positive grounding, and the power line carrier terminal device 13 is also positive grounding, so there is no need to convert the polarity between them.

A relay contact 91 is provided between the power supply side terminal 6 and the device side terminal 8. By opening and closing the relay contact 91, the supply of power to the power line carrier end station device 13 is switched between execution and cutoff. Relay contact 91 is normally closed. When the relay contact 91 is closed, power is supplied to the power line carrier terminal device 13, and when the relay contact 91 is open, the power supply to the power line carrier terminal device 13 is cut off.

The power supply control device 3 includes a communication section 31 for communicating with the remote control device 4 via the communication network 20, a power input section 32 that receives input of DC power via the DC-DC converter 7, It has a control unit 33 that controls execution and cutoff of power supply to the external circuit.

The power supply control device 3 is connected to a DC-DC converter 7 connected to a power supply side terminal 6 to which power is supplied from the distribution board 5, that is, from the distribution board 5 to the power supply side terminal 6 and the DC-DC converter. Power is supplied via 7. The power supply control device 3 normally supplies power to the external circuit, and upon receiving a cutoff signal transmitted from the remote control device 4 via the communication unit 31, cuts off the power supply to the external circuit.

A relay circuit 9 is connected to the control unit 33 of the power supply control device 3 as an external circuit. The relay circuit 9 normally receives power supply from the power supply control device 3 to close the relay contact 91, and operates when the power supply control device 3 receives a cutoff signal and cuts off the power supply to the relay circuit 9 as an external circuit. to open the relay contact 91. When the relay contact 91 is opened, the power supply is cut off and the power line carrier terminal device 13 is stopped.

Next, the function, operation, etc. of the power line transport control system 1 having such a configuration will be explained using FIG. 8 as well. Note that all reception level values in the following description are examples.

First, under normal conditions, power is supplied from the power supply control device 3 to the relay circuit 9 (step S1), and the relay contact 91 is closed (step S2), thereby supplying power to the power line carrier terminal device 13. The supply is executed (step S3), and power line carrier communication is performed using the power transmission lines 11 and 12 as transmission paths (step S4). At this time, if the working ground is not installed for the power transmission lines 11 and 12, the reception level determination task 46a is transmitted from the reception level monitoring device 2 (step S5) and the data receiving unit 41 receives the reception level determination task 46a. Based on the received reception level data transferred, it is determined that the reception level at the power line carrier end station equipment 13 is stable at around -20 dBm, and that no working ground is installed for the power transmission lines 11 and 12. do.

In the above state, when a working ground is installed for the power transmission lines 11 and 12, the reception level at the power line carrier end station device 13 decreases by about 3 dBm, resulting in about -23 dBm. At this time, the reception level determination task 46a determines that the reception level at the power line carrier end station device 13 is 3 dBm based on the reception level data transmitted from the reception level monitoring device 2 (step S6) and transferred from the data reception unit 41. As a result, it has stabilized at around -23 dBm, and it is determined that a working ground has been installed for the power transmission lines 11 and 12. Then, the reception level determination task 46a transfers the cutoff signal generation instruction to the cutoff signal generation task 46b and the alarm output task 46c (step S7).

The alarm output task 46c that receives the input of the cutoff signal generation instruction causes the display unit 43 of the remote control device 4 to display a message indicating that the working ground has been installed, or displays the message that the work ground is installed. Sound is emitted from a speaker (not shown) (step S8).

The cutoff signal generation task 46b, which has received the input of the cutoff signal generation instruction, generates a cutoff signal and transfers it to the command transmitter 42 (step S9). The command transmitter 42, which has received the input of the cutoff signal, transmits the cutoff signal to the power supply control device 3 via the communication network 20 (step S10). Then, the power supply control device 3 that has received the input of the cutoff signal cuts off the power supply to the relay circuit 9 (step S11), and as a result, the relay contact 91 is opened (step S12), and the power line carrier terminal device 13 The power supply to the terminal is cut off (step S13), and the power line carrier terminal equipment 13 is stopped (step S14).

Thereafter, the working ground installed for the power transmission lines 11 and 12 is removed, and the input unit 44 is operated by the worker to issue an instruction to resume power supply to the power line carrier terminal equipment 13. When input, the restart signal generation task 46d generates a restart signal and transfers it to the command transmitter 42 (step S15).

The command transmitter 42, which has received the restart signal, transmits the restart signal to the power supply control device 3 via the communication network 20 (step S16). Then, the power supply control device 3 that has received the restart signal restarts the power supply to the relay circuit 9 (step S17), and as a result, the relay contact 91 is closed (step S18), and the power line carrier terminal device 13 The power supply to the power line is restarted (step S19), and the power line carrier terminal device 13 is activated (step S20). In normal times, the power transmission lines 11 and 12 are used as transmission paths to perform power line carrier communication.

Although the embodiments of this invention have been described above, the specific configuration is not limited to the above embodiments, and even if there are changes in the design within the scope of the gist of this invention, Included in invention.

For example, when a plurality of remote control devices 4 are arranged to monitor power line carrier communication performed between a plurality of electric stations, communication with the plurality of remote control devices 4 is performed via the communication network 20. A general control device (not shown) may be installed to manage the plurality of remote control devices 4. In this case, it is possible to centrally manage the status of power line carrier communication performed between multiple electric stations within the managed area, and the remote control device 4 can be operated from the integrated control device. It can also be configured.

1 Power line carrier control system 2 Reception level monitoring device 3 Power supply control device 31 Communication section 32 Power input section 33 Control section 4 Remote control device 41 Data reception section 42 Command transmission section 43 Display section 44 Input section 45 Memory 46 Main task 46a Reception level Judgment task 46b Shutdown signal generation task 46c Alarm output task 46d Restart signal generation task 47 Central processing unit 5 Distribution board 6 Power supply side terminal 7 DC-DC converter 8 Device side terminal 9 Relay circuit 91 Relay contact 10A Electrical station 10B Electrical station 11 Power transmission line 12 Power transmission line 13 Power line carrier terminal equipment 14 Communication power supply 15 Coupling capacitor 16 Line coupling filter (EF)
17 Balanced coupling filter (MF) for metal circuits
18 Power line transport safety device 19 Line trap 20 Communication network

Claims (4)

a reception level monitoring device that detects a reception level at a power line carrier end station device;
a power supply control device that switches between execution and cutoff of power supply to the power line carrier end station device;
a remote control device that receives the reception level detected by the reception level monitoring device and transmits a control signal for switching the power supply to the power supply control device,
When the reception level decreases by a predetermined width, the remote control device transmits a control signal for cutting off the power supply to the power supply control device, and the power supply control device receiving the control signal operates to cut off the power supply to the power line carrier terminal device;
A power line transport control system characterized by: An input/output isolated DC-DC converter,
a relay circuit connected to the power supply control device;
The power supply control device connects to a power supply via the DC-DC converter,
The power line carrier terminal device is connected to the power source via a relay contact of the relay circuit,
The power supply control device that has received the control signal cuts off the power supply to the relay circuit and the relay contact becomes open, thereby cutting off the power supply to the power line carrier terminal device.
The power line transport control system according to claim 1, characterized in that: the predetermined width is 1 to 5 dBm;
The power line transport control system according to claim 1 or 2, characterized in that: the power supply control device is negative grounded;
the power line carrier end station device is positive grounded;
The power line transport control system according to claim 2, characterized in that:

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