JPWO2007010602A1 - Inductive coupling device for power line carrier communication system - Google Patents

Abstract

Magnetic cores 3a and 3b having apertures 20 through which power lines 2 as primary windings pass, and signal conductors 10 as secondary windings through the apertures 20 are provided. The magnetic cores 3a and 3b are installed on the sheath and grounded.

Description

  The present invention relates to an inductive coupling device for a power line carrier communication system that injects a communication signal into a power line.

  In a power line carrier communication system using a medium voltage power line as a signal transmission line, an inductive coupling device is installed on the power line, and communication is performed by coupling the signal conductor and the power line in a high frequency region. Since the power lines are either bare of the conductive metal or are covered with an insulating coating on the conductive metal, and the surface of the power line is charged with a medium-voltage system voltage, an inductive coupling device is provided with a medium-voltage insulating structure. It is necessary to incorporate.

  An example of an inductive coupling device of a conventional power line carrier communication system having such a configuration is an inductive coupling device installed on a medium voltage power line described in Patent Document 1. This inductive coupling device is composed of two magnetic cores of an upper and lower split type, a power line as a primary winding that passes through the aperture of the magnetic core, and a signal conductor as a secondary winding that also passes through the aperture. The magnetic core is electrically connected to the power line, and the magnetic core and the signal conductor are provided with an insulating structure that can withstand a medium voltage.

  Here, the power line and the magnetic core are electrically connected to eliminate the potential difference between the two to solve the insulation problem such as partial discharge, and the low-voltage signal conductor and the power line have the same potential. An insulation structure capable of withstanding medium voltage is provided between the magnetic core. Such an insulating structure is generally produced by cast hardening a solid insulator between the magnetic core and the signal conductor.

US 2003 / 0222748A1

  The inductive coupling device of the conventional power line carrier communication system is configured as described above, and it is necessary to add an intermediate voltage insulation structure between the power line as the primary winding and the signal conductor as the secondary winding. There has been a problem in that the number of parts, the number of manufacturing processes, the size of the inductive coupling device is increased, and the manufacturing cost increases.

  The present invention has been made to solve the above-described problems, and eliminates the need for an intermediate voltage insulation structure between the power line as the primary winding and the signal conductor as the secondary winding, thereby realizing a reduction in cost. It is an object to obtain an inductive coupling device for a power line carrier communication system.

  An inductive coupling device for a power line carrier communication system according to the present invention includes a magnetic core having an aperture for passing a power line as a primary winding, and a signal conductor as a secondary winding passing through the aperture, The core is installed on the grounding sheath of the power line with the grounding sheath, and the magnetic core is grounded.

  According to the present invention, it is possible to reduce the cost by eliminating the need for an insulation structure with respect to the system voltage, and to obtain the effects that the insulation reliability and the communication reliability can be improved.

It is a perspective view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention. It is a perspective view which shows the other structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention. It is a perspective view which shows the other structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention. It is a figure which shows an example of the place where the inductive coupling device of the power line carrier communication system by Embodiment 1 of this invention is actually installed. It is a figure which shows the other example of the place where the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention is actually installed. It is a figure which shows the example of a calculation result of the electric potential distribution of a magnetic core at the time of installing an inductive coupling device on the grounding sheath of an underground power line. It is a figure which shows the example of a calculation result of the electric potential distribution of a magnetic core at the time of installing the inductive coupling device of the power line carrier communication system by Embodiment 1 of this invention on the earthing | grounding sheath of an underground power line. It is a figure which shows the example of a calculation result of the electric potential distribution of a magnetic core at the time of installing the inductive coupling device of the power line carrier communication system by Embodiment 1 of this invention on the earthing | grounding sheath of an underground power line. It is a figure which shows the example of a calculation result of the electric potential distribution of a magnetic core at the time of installing the inductive coupling device of the power line carrier communication system by Embodiment 1 of this invention on the earthing | grounding sheath of an underground power line. It is a perspective view which shows the other structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention. It is a perspective view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 2 of this invention. It is a top view which shows the structure of the inductive coupling device of the power line carrier communication system by Embodiment 3 of this invention. It is a top view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 4 of this invention. It is a perspective view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 5 of this invention. It is a perspective view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 6 of this invention. It is a perspective view which shows the other structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 6 of this invention.

Hereinafter, in order to describe the present invention in more detail, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a perspective view showing a configuration of an inductive coupling device of a power line carrier communication system according to Embodiment 1 of the present invention. In this inductive coupling device 1, for example, magnetic cores 3 a and 3 b made of a magnetic material such as neodymium or ferrite are fixed with gap materials 4 a and 4 b for suppressing magnetic saturation caused by current flowing through the power line 2 being sandwiched, The power line 2 as the primary winding of the inductive coupling device 1 and the signal conductor 10 as the secondary winding pass through the aperture 20 of the magnetic cores 3a and 3b divided into two in the vertical direction of the power line 2.

  The signal conducting wire 10 is connected to the connector 9 in the connector case 8, and the connector case 8 is molded with a thermoplastic resin or a thermosetting resin in consideration of weather resistance or the like to ensure a waterproof effect. Further, a protective element such as a surge arrester (not shown) is connected to the signal conducting wire 10 in the connector case 8 to suppress the transition of the surge flowing in the power line 2 to the secondary side. A signal line 103 is connected to the connector 9, and a communication modem 104 is connected to the end of the signal line 103. The inductive coupling device 1 injects a communication signal from the communication modem 104 into the power line 2 or extracts a communication signal transmitted from the other communication modem and transmitted through the power line 2.

  The power line 2 includes a cable conductor 31, an insulator 32 outside the cable conductor 31, a ground sheath 33 outside the insulator 32, and a cable jacket 34 outside the ground sheath 33 at the center. The central cable conductor 31 is charged with the system voltage of the power line 2 and is protected by a grounding sheath 33 so that the transmission voltage does not leak outside.

  The magnetic cores 3a and 3b are roughly divided into four surfaces, which are referred to as an outer peripheral surface 21, an upper surface 22, a lower surface 23, and an inner peripheral surface 24, respectively. Among them, the outer peripheral surface 21 is provided with conductive walls 5a and 5b by applying a conductive paint or bonding and fixing a metal plate, etc., and a ground wire 7 is connected to the ground terminals 6a and 6b attached to the walls 5a and 6b. Is done.

  2 and 3 are perspective views showing another configuration of the inductive coupling device of the power line carrier communication system according to the first embodiment of the present invention. In FIG. 1, conductive walls 5a and 5b are provided on the outer peripheral surface 21 of the magnetic cores 3a and 3b and are grounded by the ground terminals 6a and 6b and the ground wire 7. In FIG. 2, the upper surfaces of the magnetic cores 3a and 3b are provided. In FIG. 3, conductive walls 11a and 11b are provided, and in FIG. 3, conductive walls 12a and 12b are provided on the lower surface 23 of the magnetic cores 3a and 3b, and are grounded by ground terminals 6a and 6b and a ground wire 7, respectively. Other configurations in FIGS. 2 and 3 are the same as those in FIG.

  FIG. 4 is a diagram showing an example of a place where the inductive coupling device 1 is actually installed. An overhead power line 101 is hung on the utility pole 102, and an underground power line 106 is connected as a branch. The underground power line 106 as the power line 2 in FIGS. 1 to 3 is, as described above, the outside of the cable conductor 31 (not shown) which is a charging unit via an insulator 32 (not shown). Are grounded by a grounding sheath 33 (not shown). The ground sheath 33 is interrupted by the terminal processing unit 108, and the center cable conductor 31 is exposed at the tip of the ground sheath 33 and connected to the overhead power line 101. The inductive coupling device 1 is installed at a site where the grounding sheath 33 of the underground power line 106 under the terminal processing unit 108 is present. A signal line 103 is connected to a secondary connector 9 (not shown) of the inductive coupling device 1, and a communication modem 104 is connected to the end of the signal line 103.

  FIG. 5 is a diagram showing another example of a place where the inductive coupling device 1 is actually installed. Here, a transformer lead-out line 110 is provided from a transformer 105 provided in the substation, and a cable conductor 31 (not shown) of the underground power line 106 is connected to the end of the transformer lead-out line 110. The configuration of the underground power line 106 is the same as that of the underground power line 106 shown in FIG. The inductive coupling device 1 is installed at a site where the grounding sheath 33 (not shown) of the underground power line 106 under the terminal processing unit 108 is present. A signal line 103 is connected to a secondary connector 9 (not shown) of the inductive coupling device 1, and a communication modem 104 is connected to the end of the signal line 103.

  In FIG. 4 and FIG. 5, the aerial power line 101 and the transformer lead-out line 110 have exposed charging portions. In order to inject a communication signal into these, an insulative structure that can withstand the system voltage is inductively coupled device 1. In the middle voltage class of several kV to several tens of kV, such an insulating structure is a factor that increases the cost of the inductive coupling device 1. Therefore, when communication is performed using the overhead power line 101 and the transformer lead-out line 110, the ground power line 106 with the ground sheath 33 is connected to the ground power line 106 on the ground sheath 33. If the inductive coupling device 1 is installed in the center, the object can be achieved. In this case, it is possible to omit an insulation structure that is directly attached to a medium voltage charging unit.

Next, as shown in FIGS. 4 and 5, the potential increase of the magnetic cores 3 a and 3 b when the inductive coupling device 1 is installed on the grounding sheath 33 of the underground power line 106 will be described.
FIG. 6 is a diagram showing a calculation result example of the potential distribution of the magnetic core 3 when the inductive coupling device 1 is installed on the grounding sheath 33 of the underground power line 106. 7 to 9 show examples of calculation results of the potential distribution of the magnetic core 3 when the inductive coupling device 1 according to the first embodiment of the present invention is installed on the grounding sheath 33 of the underground power line 106. It is. In FIGS. 6 to 9, the potential distribution in the axial target analysis model when the central axis of the underground power line 106 cable conductor 31 is the target axis 201 and the magnetic core 3 is installed on the grounding sheath 33 of the underground power line 106. Is shown as a cross-sectional view including the target axis 201.

  As the magnetic core 3 of the inductive coupling device 1, a magnetic material such as neodymium or ferrite can be used. When a material having a low volume resistivity such as neodymium is used, one or two points of the magnetic core 3 are provided. The entire magnetic core 3 can be suppressed to a low potential by grounding, but when a material having a high volume resistivity such as ferrite is used, a conductive wall 5 is provided on the surface on which the magnetic core 3 is provided. It is necessary to ground the whole. The potential of the magnetic core 3 shown in FIGS. 6 to 9 is an example of calculation results when a ferrite system having a high volume resistivity is used as the magnetic material.

  FIG. 6 shows the calculation result of the potential distribution of the magnetic core 3 when the magnetic core 3 is not grounded without providing the conductive wall 5 on the magnetic core 3. The target axis 201 is the central axis of the cable conductor 31, and the insulator 32 is present outside the cable conductor 31 (on the right side in the figure). The outside of the insulator 32 is divided into a region 211 without the grounding sheath 33 and a region 212 with the grounding sheath 33. The magnetic core 3 is installed outside the region 212 where the grounding sheath 33 is located.

  The calculation result of the potential distribution is represented by an equipotential line 202, and shows the potential of the equipotential line 202 near the magnetic core 3 when the potential of the cable conductor 31 is 100% and the potential of the grounding sheath 33 is 0%. . According to the calculation, the potential of the magnetic core 3 is between 6.3 and 8.8%. If the system voltage is 24 kV and the ground voltage is 24 / √3 KV, the potential of the magnetic core 3 is 870 to 1220 V. It means to become. The calculation results vary depending on the installation distance of the inductive coupling device 1 from the cable end of the underground power line 106, the positional relationship with the peripheral device charging unit, etc., but actually, as shown in FIG. 1 to FIG. The signal conductor 10 is circulated around the core 3, and a partial discharge may occur between the magnetic core 3 and the low voltage signal conductor 10, which may impair insulation reliability or cause communication failure. is there.

  In FIG. 6, a ferrite material having a high volume resistivity is used as the magnetic material of the magnetic core 3. However, even if a neodymium material having a low volume resistivity is used as the magnetic material, there is a large difference in the degree of potential increase. There is no.

  Therefore, in the inductive coupling device 1 of the power line carrier communication system according to the first embodiment of the present invention, when the conductive wall 5 is provided on the outer peripheral surface 21 of the magnetic core 3 and grounded as shown in FIG. It can be seen that the potential is 1.3% or less, and that the potential increase of the magnetic core 3 can be effectively suppressed.

  Further, as shown in FIG. 8, even if the conductive wall 11 is provided on the upper surface 22 of the magnetic core 3, the potential increase can be suppressed to 3.8% or less. Further, as shown in FIG. It can be seen that even if the conductive wall 12 is provided on the lower surface 23, the potential increase can be suppressed to 3.8% or less.

  In addition, although the inner peripheral surface 24 of the magnetic core 3 of FIGS. 1 to 3 is also possible as a place where the conductive wall for suppressing the potential rise of the magnetic core 3 is provided, in this case, as the inductive coupling device 1 It is better to avoid the inductive coupling, which is the basic function of, because it is reduced by the magnetic shielding effect of the conductive wall. That is, the potential increase of the magnetic core 3 is suppressed by providing a conductive wall on all surfaces except the inner peripheral surface 24 of the magnetic core 3 or any one surface except the inner peripheral surface 24 and grounding. Further, the effect can be efficiently obtained by providing the conductive wall 5 on the outer peripheral surface 21 of the magnetic core 3 and grounding it, and the inductive coupling device 1 having high insulation reliability and communication reliability can be configured. Become.

  FIG. 10 is a perspective view showing another configuration of the inductive coupling device of the power line carrier communication system according to Embodiment 1 of the present invention. In FIG. 10, a plurality of magnetic cores 3 a-1, 3 b-1, 3 a-2, 3 b-2, 3 a-3, and 3 b-3 are connected in the direction perpendicular to the axial direction of the power line 2. It is composed. In order to obtain the coupling characteristics of the inductive coupling device 1, a certain size of the magnetic core 3 is required. However, when the large magnetic core 3 is manufactured integrally, the shrinkage strain at the time of firing the core is large. Since deformation and cracking are likely to occur, a high manufacturing technique is required and the yield is deteriorated, resulting in an increase in manufacturing cost.

  Therefore, the magnetic core 3 is divided and fired in the direction perpendicular to the axial direction of the power line 2 and arranged or bonded side by side to form a single magnetic core 3, thereby reducing the magnetic properties without affecting the magnetic characteristics. The inductive coupling device 1 can be manufactured at a low cost. In this case, the conductive walls 5b-1, 5b-2, 5b-3 of the magnetic cores 3b-1, 3b-2, 3b-3 are electrically connected by the ground bridges 11b, 12b, and the ground terminal 6b and the ground wire 7 are connected. If the grounding is performed via the, the potential increase of the magnetic core 3b can be reliably suppressed. Although not shown in FIG. 10, in this case, the magnetic cores 3a-1, 3a-2, 3a-3 are also electrically connected by the ground bridges 11a, 12a, and are connected via the ground terminal 6a and the ground line 7. And the potential rise of the magnetic core 3a can be reliably suppressed.

  As described above, according to the first embodiment, when a communication signal is injected into a lead line of a power device having a charging exposure part such as the overhead power line 101 and the transformer lead line 110, an inductive coupling device is provided in the charging part. Inductive coupling device 1 is installed in underground power line 106 with grounding sheath 33 connected in the vicinity thereof, and all surfaces except for inner peripheral surface 24 of magnetic core 3 of inductive coupling device 1 are installed. Or, by providing conductive walls 5, 11 and 12 on either side and grounding, it is possible to reduce the cost by eliminating the need for an insulation structure for the system voltage, and to improve insulation reliability and communication reliability. The effect of being able to be obtained.

Embodiment 2. FIG.
FIG. 11 is a perspective view showing a configuration of an inductive coupling device of a power line carrier communication system according to Embodiment 2 of the present invention. The conductive walls 5 a and 5 b of the magnetic cores 3 a and 3 b are connected to the ground wire 7 through the ground terminals 6 a and 6 b, and the ground wire 7 is electrically connected to the signal conductor 10 inside the connector case 8. The signal conductor 10 is connected to the communication modem 104 through the signal line 103. In the communication modem 104, the signal line 103 is grounded with a predetermined impedance that does not cause an increase in potential of the magnetic cores 3a and 3b with respect to the power frequency. . Other configurations are the same as those in FIG. 1 of the first embodiment.

  As described above, according to the second embodiment, the same effects as those of the first embodiment can be obtained, and the ground of the magnetic cores 3a and 3b can be connected to the signal modem 10 through the signal line 103 and the communication modem 104 side. As a result, the ground wire wiring / connection work is not required for the installation of the inductive coupling device 1, and the installation cost can be reduced.

Embodiment 3 FIG.
FIG. 12 is a top view showing the configuration of the inductive coupling device of the power line carrier communication system according to the third embodiment of the present invention, and is a view of the inductive coupling device 1 as viewed from above together with the cross section of the power line 2. Here, elastic bodies 41a and 41b are attached to the inner walls of the magnetic cores 3a and 3b. The inner diameters of the elastic bodies 41a and 41b are smaller than the outer dimensions of the power line 2. The power line 2 includes a cable conductor 31, an insulator 32, a grounding sheath 33, and a cable jacket 34. Other configurations are the same as those in FIG. 1 of the first embodiment.

  When installing the inductive coupling device 1 on the power line 2, the magnetic cores 3 a and 3 b that are divided into two parts are opened and covered with the power line 2, and the magnetic core 3 a is fixed with a fixture (not shown) such as a clamp or a screw-tightened metal band. , 3b is fixed so as to close with the gap members 4a, 4b interposed therebetween. At this time, the elastic bodies 41 a and 41 b are pressed and deformed against the cable jacket 34 of the power line 2, and the inductive coupling device 1 is fixed to the power line 2 by the elastic force. As the elastic bodies 41a and 41b, for example, silicon rubber, ethylene propylene rubber or the like can be used.

  As described above, according to the third embodiment, the same effects as those of the first embodiment can be obtained, and the structure in which the inductive coupling device 1 is fixed using the elastic bodies 41a and 41b can be simplified. The inductive coupling device 1 can be fixed to the power line 2 with a simple structure, and the effect that the installation cost can be reduced is obtained.

Embodiment 4 FIG.
FIG. 13 is a top view showing the configuration of the inductive coupling device of the power line carrier communication system according to the fourth embodiment of the present invention, and is a view of the inductive coupling device 1 as viewed from above together with the cross section of the power line 2. Holding plates 42a and 42b are attached to the inner walls of the magnetic cores 3a and 3b via springs 43a and 43b. The inner diameter dimensions of the pressing plates 42 a and 42 b are smaller than the outer dimension of the power line 2. The power line 2 includes a cable conductor 31, an insulator 32, a grounding sheath 33, and a cable jacket 34. Other configurations are the same as those in FIG. 1 of the first embodiment.

  When installing the inductive coupling device 1 on the power line 2, the magnetic cores 3 a and 3 b which are divided into two parts are opened and covered with the power line 2, and the magnetic core is fixed by a clamp or a screw-tightening metal band or the like (not shown). 3a and 3b are fixed so as to close with the gap members 4a and 4b interposed therebetween. At this time, the springs 43 a and 43 b are compressed, and the holding plates 42 a and 42 b are pressed against the cable jacket 34 of the power line 2 by the spring force, and the inductive coupling device 1 is fixed to the power line 2.

  As described above, according to the fourth embodiment, the same effect as that of the first embodiment can be obtained, and a long structure can be obtained by fixing the inductive coupling device 1 by the spring force of the springs 43a and 43b. Even when the inductive coupling device 1 is installed on the power line 2 over a period of time, since the fixing structure can stably exhibit the contact pressure with the power line 2, an effect that a highly reliable fixing structure can be obtained is obtained.

Embodiment 5 FIG.
FIG. 14 is a perspective view showing a configuration of an inductive coupling device of a power line carrier communication system according to Embodiment 5 of the present invention. In FIG. 14, the holding band 13 circulates around the magnetic core 3 b to form a loop smaller than the loop formed by the signal conductor 10, and the signal conductor is formed by the connector case 8 that fixes the end of the signal conductor 10. 10 is fixed together. Other configurations are the same as those in FIG. 1 of the first embodiment. Although mechanical stress is applied to the signal conductor 10 through the signal line 103, the mechanical stress is reduced by the holding band 13 to prevent the signal conductor 10 from being disconnected.

  As described above, according to the fifth embodiment, the same effect as in the first embodiment can be obtained, and the holding band 13 forming a loop smaller than the loop formed by the signal conducting wire 10 can be used. By reducing the mechanical stress applied to the signal conducting wire 10, it is possible to prevent the signal conducting wire 10 from being disconnected.

Embodiment 6 FIG.
FIG. 15 is a perspective view showing the configuration of an inductive coupling device of a power line carrier communication system according to Embodiment 6 of the present invention. In FIG. 15, the holding band 13 is formed of a conductor, the conductive wall 5 b provided on the outer peripheral surface 21 of the magnetic core 3 b is electrically connected to the holding band 13, and the holding band 13 is in the connector case 8. Are electrically connected to the signal conductor 10. The signal conductor 10 is connected to the communication modem 104 via the signal line 103, and is grounded with a predetermined impedance such that the potential rise of the magnetic cores 3a and 3b does not cause a problem with respect to the power frequency. The conductive wall 5 a provided on the outer peripheral surface 21 of the magnetic core 3 a is electrically connected to the conductive wall 5 b by the ground bridge 14. Other configurations are the same as those in FIG. 14 of the fifth embodiment.

  In this way, the conductive walls 5a and 5b of the magnetic cores 3a and 3b are grounded via the holding band 13 formed of a conductor, so that wiring and connection work of the ground wire are not required.

  FIG. 16 is a perspective view showing another configuration of the inductive coupling device of the power line carrier communication system according to the sixth embodiment of the present invention. In FIG. 16, the conductive wall 11b provided on the upper surface 22 of the magnetic core 3b is electrically connected to the holding band 13 which is a conductor. The signal conductor 10 is connected to the communication modem 104 via the signal line 103, and is grounded with a predetermined impedance such that the potential rise of the magnetic cores 3a and 3b does not cause a problem with respect to the power frequency. Further, the conductive wall 11 a provided on the upper surface 22 of the magnetic core 3 a is electrically connected to the conductive wall 11 b and the ground bridge 14. Other configurations are the same as those in FIG. 14 of the fifth embodiment.

  In this manner, the conductive walls 11a and 11b of the magnetic cores 3a and 3b are grounded via the holding band 13 formed of a conductor, thereby eliminating the need for wiring of the ground wire and connection work.

  As described above, according to the sixth embodiment, the same effect as in the first embodiment can be obtained, and the conductive walls 5a, 3b of the magnetic cores 3a, 3b can be provided via the holding band 13 formed of a conductor. By grounding 5b or the conductive walls 11a and 11b, there is no need for grounding wires and connection work, and the installation cost of the inductive coupling device can be reduced.

  As described above, the inductive coupling device of the power line carrier communication system according to the present invention is suitable for a device that eliminates the need for an insulation structure for the system voltage.

  The present invention relates to an inductive coupling device for a power line carrier communication system that injects a communication signal into a power line.

  In a power line carrier communication system using a medium voltage power line as a signal transmission line, an inductive coupling device is installed on the power line, and communication is performed by coupling the signal conductor and the power line in a high frequency region. Since the power lines are either bare of the conductive metal or are covered with an insulating coating on the conductive metal, and the surface of the power line is charged with a medium-voltage system voltage, an inductive coupling device is provided with a medium-voltage insulating structure. It is necessary to incorporate.

  An example of an inductive coupling device of a conventional power line carrier communication system having such a configuration is an inductive coupling device installed on a medium voltage power line described in Patent Document 1. This inductive coupling device is composed of two magnetic cores of an upper and lower split type, a power line as a primary winding that passes through the aperture of the magnetic core, and a signal conductor as a secondary winding that also passes through the aperture. The magnetic core is electrically connected to the power line, and the magnetic core and the signal conductor are provided with an insulating structure that can withstand a medium voltage.

  Here, the power line and the magnetic core are electrically connected to eliminate the potential difference between the two to solve the insulation problem such as partial discharge, and the low-voltage signal conductor and the power line have the same potential. An insulation structure capable of withstanding medium voltage is provided between the magnetic core. Such an insulating structure is generally produced by cast hardening a solid insulator between the magnetic core and the signal conductor.

US 2003 / 0222748A1

  The inductive coupling device of the conventional power line carrier communication system is configured as described above, and it is necessary to add an intermediate voltage insulation structure between the power line as the primary winding and the signal conductor as the secondary winding. There has been a problem in that the number of parts, the number of manufacturing processes, the size of the inductive coupling device is increased, and the manufacturing cost increases.

  The present invention has been made to solve the above-described problems, and eliminates the need for an intermediate voltage insulation structure between the power line as the primary winding and the signal conductor as the secondary winding, thereby realizing a reduction in cost. It is an object to obtain an inductive coupling device for a power line carrier communication system.

An inductive coupling device for a power line carrier communication system according to the present invention includes a magnetic core having an aperture for passing a power line as a primary winding, and a signal conductor as a secondary winding passing through the aperture, A core is installed on a grounding sheath of a power line with a grounding sheath, the magnetic core is grounded , and a conductive wall is provided on the surface of any one of the magnetic cores except the inner peripheral surface of the magnetic core facing the power line; the conductive wall is shall be grounded.

  According to the present invention, it is possible to reduce the cost by eliminating the need for an insulation structure with respect to the system voltage, and to obtain the effects that the insulation reliability and the communication reliability can be improved.

Hereinafter, in order to describe the present invention in more detail, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
FIG. 1 is a perspective view showing a configuration of an inductive coupling device of a power line carrier communication system according to Embodiment 1 of the present invention. In this inductive coupling device 1, for example, magnetic cores 3 a and 3 b made of a magnetic material such as neodymium or ferrite are fixed with gap materials 4 a and 4 b for suppressing magnetic saturation caused by current flowing through the power line 2 being sandwiched, The power line 2 as the primary winding of the inductive coupling device 1 and the signal conductor 10 as the secondary winding pass through the aperture 20 of the magnetic cores 3a and 3b divided into two in the vertical direction of the power line 2.

  The signal conducting wire 10 is connected to the connector 9 in the connector case 8, and the connector case 8 is molded with a thermoplastic resin or a thermosetting resin in consideration of weather resistance or the like to ensure a waterproof effect. Further, a protective element such as a surge arrester (not shown) is connected to the signal conducting wire 10 in the connector case 8 to suppress the transition of the surge flowing in the power line 2 to the secondary side. A signal line 103 is connected to the connector 9, and a communication modem 104 is connected to the end of the signal line 103. The inductive coupling device 1 injects a communication signal from the communication modem 104 into the power line 2 or extracts a communication signal transmitted from the other communication modem and transmitted through the power line 2.

  The power line 2 includes a cable conductor 31, an insulator 32 outside the cable conductor 31, a ground sheath 33 outside the insulator 32, and a cable jacket 34 outside the ground sheath 33 at the center. The central cable conductor 31 is charged with the system voltage of the power line 2 and is protected by a grounding sheath 33 so that the transmission voltage does not leak outside.

  The magnetic cores 3a and 3b are roughly divided into four surfaces, which are referred to as an outer peripheral surface 21, an upper surface 22, a lower surface 23, and an inner peripheral surface 24, respectively. Among them, the outer peripheral surface 21 is provided with conductive walls 5a and 5b by applying a conductive paint or bonding and fixing a metal plate, etc., and a ground wire 7 is connected to the ground terminals 6a and 6b attached to the walls 5a and 6b. Is done.

  2 and 3 are perspective views showing another configuration of the inductive coupling device of the power line carrier communication system according to the first embodiment of the present invention. In FIG. 1, conductive walls 5a and 5b are provided on the outer peripheral surface 21 of the magnetic cores 3a and 3b and are grounded by the ground terminals 6a and 6b and the ground wire 7. In FIG. 2, the upper surfaces of the magnetic cores 3a and 3b are provided. In FIG. 3, conductive walls 11a and 11b are provided, and in FIG. 3, conductive walls 12a and 12b are provided on the lower surface 23 of the magnetic cores 3a and 3b, and are grounded by ground terminals 6a and 6b and a ground wire 7, respectively. Other configurations in FIGS. 2 and 3 are the same as those in FIG.

  FIG. 4 is a diagram showing an example of a place where the inductive coupling device 1 is actually installed. An overhead power line 101 is hung on the utility pole 102, and an underground power line 106 is connected as a branch. The underground power line 106 as the power line 2 in FIGS. 1 to 3 is, as described above, the outside of the cable conductor 31 (not shown) which is a charging unit via an insulator 32 (not shown). Are grounded by a grounding sheath 33 (not shown). The ground sheath 33 is interrupted by the terminal processing unit 108, and the center cable conductor 31 is exposed at the tip of the ground sheath 33 and connected to the overhead power line 101. The inductive coupling device 1 is installed at a site where the grounding sheath 33 of the underground power line 106 under the terminal processing unit 108 is present. A signal line 103 is connected to a secondary connector 9 (not shown) of the inductive coupling device 1, and a communication modem 104 is connected to the end of the signal line 103.

  FIG. 5 is a diagram showing another example of a place where the inductive coupling device 1 is actually installed. Here, a transformer lead-out line 110 is provided from a transformer 105 provided in the substation, and a cable conductor 31 (not shown) of the underground power line 106 is connected to the end of the transformer lead-out line 110. The configuration of the underground power line 106 is the same as that of the underground power line 106 shown in FIG. The inductive coupling device 1 is installed at a site where the grounding sheath 33 (not shown) of the underground power line 106 under the terminal processing unit 108 is present. A signal line 103 is connected to a secondary connector 9 (not shown) of the inductive coupling device 1, and a communication modem 104 is connected to the end of the signal line 103.

  In FIG. 4 and FIG. 5, the aerial power line 101 and the transformer lead-out line 110 have exposed charging portions. In order to inject a communication signal into these, an insulative structure that can withstand the system voltage is inductively coupled device 1. In the middle voltage class of several kV to several tens of kV, such an insulating structure is a factor that increases the cost of the inductive coupling device 1. Therefore, when communication is performed using the overhead power line 101 and the transformer lead-out line 110, the ground power line 106 with the ground sheath 33 is connected to the ground power line 106 on the ground sheath 33. If the inductive coupling device 1 is installed in the center, the object can be achieved. In this case, it is possible to omit an insulation structure that is directly attached to a medium voltage charging unit.

Next, as shown in FIGS. 4 and 5, the potential increase of the magnetic cores 3 a and 3 b when the inductive coupling device 1 is installed on the grounding sheath 33 of the underground power line 106 will be described.
FIG. 6 is a diagram showing a calculation result example of the potential distribution of the magnetic core 3 when the inductive coupling device 1 is installed on the grounding sheath 33 of the underground power line 106. 7 to 9 show examples of calculation results of the potential distribution of the magnetic core 3 when the inductive coupling device 1 according to the first embodiment of the present invention is installed on the grounding sheath 33 of the underground power line 106. It is. In FIGS. 6 to 9, the potential distribution in the axial target analysis model when the central axis of the underground power line 106 cable conductor 31 is the target axis 201 and the magnetic core 3 is installed on the grounding sheath 33 of the underground power line 106. Is shown as a cross-sectional view including the target axis 201.

  As the magnetic core 3 of the inductive coupling device 1, a magnetic material such as neodymium or ferrite can be used. When a material having a low volume resistivity such as neodymium is used, one or two points of the magnetic core 3 are provided. The entire magnetic core 3 can be suppressed to a low potential by grounding, but when a material having a high volume resistivity such as ferrite is used, a conductive wall 5 is provided on the surface on which the magnetic core 3 is provided. It is necessary to ground the whole. The potential of the magnetic core 3 shown in FIGS. 6 to 9 is an example of calculation results when a ferrite system having a high volume resistivity is used as the magnetic material.

  FIG. 6 shows the calculation result of the potential distribution of the magnetic core 3 when the magnetic core 3 is not grounded without providing the conductive wall 5 on the magnetic core 3. The target axis 201 is the central axis of the cable conductor 31, and the insulator 32 is present outside the cable conductor 31 (on the right side in the figure). The outside of the insulator 32 is divided into a region 211 without the grounding sheath 33 and a region 212 with the grounding sheath 33. The magnetic core 3 is installed outside the region 212 where the grounding sheath 33 is located.

  The calculation result of the potential distribution is represented by an equipotential line 202, and shows the potential of the equipotential line 202 near the magnetic core 3 when the potential of the cable conductor 31 is 100% and the potential of the grounding sheath 33 is 0%. . According to the calculation, the potential of the magnetic core 3 is between 6.3 and 8.8%. If the system voltage is 24 kV and the ground voltage is 24 / √3 KV, the potential of the magnetic core 3 is 870 to 1220 V. It means to become. The calculation results vary depending on the installation distance of the inductive coupling device 1 from the cable end of the underground power line 106, the positional relationship with the peripheral device charging unit, etc., but actually, as shown in FIG. 1 to FIG. The signal conductor 10 is circulated around the core 3, and a partial discharge may occur between the magnetic core 3 and the low voltage signal conductor 10, which may impair insulation reliability or cause communication failure. is there.

  In FIG. 6, a ferrite material having a high volume resistivity is used as the magnetic material of the magnetic core 3. However, even if a neodymium material having a low volume resistivity is used as the magnetic material, there is a large difference in the degree of potential increase. There is no.

  Therefore, in the inductive coupling device 1 of the power line carrier communication system according to the first embodiment of the present invention, when the conductive wall 5 is provided on the outer peripheral surface 21 of the magnetic core 3 and grounded as shown in FIG. It can be seen that the potential is 1.3% or less, and that the potential increase of the magnetic core 3 can be effectively suppressed.

  Further, as shown in FIG. 8, even if the conductive wall 11 is provided on the upper surface 22 of the magnetic core 3, the potential increase can be suppressed to 3.8% or less. Further, as shown in FIG. It can be seen that even if the conductive wall 12 is provided on the lower surface 23, the potential increase can be suppressed to 3.8% or less.

  In addition, although the inner peripheral surface 24 of the magnetic core 3 of FIGS. 1 to 3 is also possible as a place where the conductive wall for suppressing the potential rise of the magnetic core 3 is provided, in this case, as the inductive coupling device 1 It is better to avoid the inductive coupling, which is the basic function of, because it is reduced by the magnetic shielding effect of the conductive wall. That is, the potential increase of the magnetic core 3 is suppressed by providing a conductive wall on all surfaces except the inner peripheral surface 24 of the magnetic core 3 or any one surface except the inner peripheral surface 24 and grounding. Further, the effect can be efficiently obtained by providing the conductive wall 5 on the outer peripheral surface 21 of the magnetic core 3 and grounding it, and the inductive coupling device 1 having high insulation reliability and communication reliability can be configured. Become.

  FIG. 10 is a perspective view showing another configuration of the inductive coupling device of the power line carrier communication system according to Embodiment 1 of the present invention. In FIG. 10, a plurality of magnetic cores 3 a-1, 3 b-1, 3 a-2, 3 b-2, 3 a-3, and 3 b-3 are connected in the direction perpendicular to the axial direction of the power line 2. It is composed. In order to obtain the coupling characteristics of the inductive coupling device 1, a certain size of the magnetic core 3 is required. However, when the large magnetic core 3 is manufactured integrally, the shrinkage strain at the time of firing the core is large. Since deformation and cracking are likely to occur, a high manufacturing technique is required and the yield is deteriorated, resulting in an increase in manufacturing cost.

Therefore, the magnetic core 3 is divided and fired in the direction perpendicular to the axial direction of the power line 2 and arranged or bonded side by side to form a single magnetic core 3, thereby reducing the magnetic properties without affecting the magnetic characteristics. The inductive coupling device 1 can be manufactured at a low cost. In this case, the conductive walls 5b-1, 5b-2, 5b-3 of the magnetic cores 3b-1, 3b-2, 3b-3 are electrically connected by the ground bridges 14a, 14b , and the ground terminal 6b and the ground wire 7 are connected. If the grounding is performed via the, the potential increase of the magnetic core 3b can be reliably suppressed. Although not shown in FIG. 10, in this case, the conductive walls 5a-1, 5a-2, 5a- 3 of the magnetic cores 3a-1, 3a-2, 3a -3 are also grounded bridges (not shown). And is grounded via the grounding terminal 6a and the grounding wire 7, and the potential increase of the magnetic core 3a can be reliably suppressed.

  As described above, according to the first embodiment, when a communication signal is injected into a lead line of a power device having a charging exposure part such as the overhead power line 101 and the transformer lead line 110, an inductive coupling device is provided in the charging part. Inductive coupling device 1 is installed in underground power line 106 with grounding sheath 33 connected in the vicinity thereof, and all surfaces except for inner peripheral surface 24 of magnetic core 3 of inductive coupling device 1 are installed. Or, by providing conductive walls 5, 11 and 12 on either side and grounding, it is possible to reduce the cost by eliminating the need for an insulation structure for the system voltage, and to improve insulation reliability and communication reliability. The effect of being able to be obtained.

Embodiment 2. FIG.
FIG. 11 is a perspective view showing a configuration of an inductive coupling device of a power line carrier communication system according to Embodiment 2 of the present invention. The conductive walls 5 a and 5 b of the magnetic cores 3 a and 3 b are connected to the ground wire 7 through the ground terminals 6 a and 6 b, and the ground wire 7 is electrically connected to the signal conductor 10 inside the connector case 8. The signal conductor 10 is connected to the communication modem 104 through the signal line 103. In the communication modem 104, the signal line 103 is grounded with a predetermined impedance that does not cause an increase in potential of the magnetic cores 3a and 3b with respect to the power frequency. . Other configurations are the same as those in FIG. 1 of the first embodiment.

  As described above, according to the second embodiment, the same effects as those of the first embodiment can be obtained, and the ground of the magnetic cores 3a and 3b can be connected to the signal modem 10 through the signal line 103 and the communication modem 104 side. As a result, the ground wire wiring / connection work is not required for the installation of the inductive coupling device 1, and the installation cost can be reduced.

Embodiment 3 FIG.
FIG. 12 is a top view showing the configuration of the inductive coupling device of the power line carrier communication system according to the third embodiment of the present invention, and is a view of the inductive coupling device 1 as viewed from above together with the cross section of the power line 2. Here, elastic bodies 41a and 41b are attached to the inner walls of the magnetic cores 3a and 3b. The inner diameters of the elastic bodies 41a and 41b are smaller than the outer dimensions of the power line 2. The power line 2 includes a cable conductor 31, an insulator 32, a grounding sheath 33, and a cable jacket 34. Other configurations are the same as those in FIG. 1 of the first embodiment.

  When installing the inductive coupling device 1 on the power line 2, the magnetic cores 3 a and 3 b that are divided into two parts are opened and covered with the power line 2, and the magnetic core 3 a is fixed with a fixture (not shown) such as a clamp or a screw-tightened metal band. , 3b is fixed so as to close with the gap members 4a, 4b interposed therebetween. At this time, the elastic bodies 41 a and 41 b are pressed and deformed against the cable jacket 34 of the power line 2, and the inductive coupling device 1 is fixed to the power line 2 by the elastic force. As the elastic bodies 41a and 41b, for example, silicon rubber, ethylene propylene rubber or the like can be used.

  As described above, according to the third embodiment, the same effects as those of the first embodiment can be obtained, and the structure in which the inductive coupling device 1 is fixed using the elastic bodies 41a and 41b can be simplified. The inductive coupling device 1 can be fixed to the power line 2 with a simple structure, and the effect that the installation cost can be reduced is obtained.

Embodiment 4 FIG.
FIG. 13 is a top view showing the configuration of the inductive coupling device of the power line carrier communication system according to the fourth embodiment of the present invention, and is a view of the inductive coupling device 1 as viewed from above together with the cross section of the power line 2. Holding plates 42a and 42b are attached to the inner walls of the magnetic cores 3a and 3b via springs 43a and 43b. The inner diameter dimensions of the pressing plates 42 a and 42 b are smaller than the outer dimension of the power line 2. The power line 2 includes a cable conductor 31, an insulator 32, a grounding sheath 33, and a cable jacket 34. Other configurations are the same as those in FIG. 1 of the first embodiment.

  When installing the inductive coupling device 1 on the power line 2, the magnetic cores 3 a and 3 b which are divided into two parts are opened and covered with the power line 2, and the magnetic core is fixed by a clamp or a screw-tightening metal band or the like (not shown). 3a and 3b are fixed so as to close with the gap members 4a and 4b interposed therebetween. At this time, the springs 43 a and 43 b are compressed, and the holding plates 42 a and 42 b are pressed against the cable jacket 34 of the power line 2 by the spring force, and the inductive coupling device 1 is fixed to the power line 2.

  As described above, according to the fourth embodiment, the same effect as that of the first embodiment can be obtained, and a long structure can be obtained by fixing the inductive coupling device 1 by the spring force of the springs 43a and 43b. Even when the inductive coupling device 1 is installed on the power line 2 over a period of time, since the fixing structure can stably exhibit the contact pressure with the power line 2, an effect that a highly reliable fixing structure can be obtained is obtained.

Embodiment 5 FIG.
FIG. 14 is a perspective view showing a configuration of an inductive coupling device of a power line carrier communication system according to Embodiment 5 of the present invention. In FIG. 14, the holding band 13 circulates around the magnetic core 3 b to form a loop smaller than the loop formed by the signal conductor 10, and the signal conductor is formed by the connector case 8 that fixes the end of the signal conductor 10. 10 is fixed together. Other configurations are the same as those in FIG. 1 of the first embodiment. Although mechanical stress is applied to the signal conductor 10 through the signal line 103, the mechanical stress is reduced by the holding band 13 to prevent the signal conductor 10 from being disconnected.

  As described above, according to the fifth embodiment, the same effect as in the first embodiment can be obtained, and the holding band 13 forming a loop smaller than the loop formed by the signal conducting wire 10 can be used. By reducing the mechanical stress applied to the signal conducting wire 10, it is possible to prevent the signal conducting wire 10 from being disconnected.

Embodiment 6 FIG.
FIG. 15 is a perspective view showing the configuration of an inductive coupling device of a power line carrier communication system according to Embodiment 6 of the present invention. In FIG. 15, the holding band 13 is formed of a conductor, the conductive wall 5 b provided on the outer peripheral surface 21 of the magnetic core 3 b is electrically connected to the holding band 13, and the holding band 13 is in the connector case 8. Are electrically connected to the signal conductor 10. The signal conductor 10 is connected to the communication modem 104 via the signal line 103, and is grounded with a predetermined impedance such that the potential rise of the magnetic cores 3a and 3b does not cause a problem with respect to the power frequency. The conductive wall 5 a provided on the outer peripheral surface 21 of the magnetic core 3 a is electrically connected to the conductive wall 5 b by the ground bridge 14. Other configurations are the same as those in FIG. 14 of the fifth embodiment.

  In this way, the conductive walls 5a and 5b of the magnetic cores 3a and 3b are grounded via the holding band 13 formed of a conductor, so that wiring and connection work of the ground wire are not required.

  FIG. 16 is a perspective view showing another configuration of the inductive coupling device of the power line carrier communication system according to the sixth embodiment of the present invention. In FIG. 16, the conductive wall 11b provided on the upper surface 22 of the magnetic core 3b is electrically connected to the holding band 13 which is a conductor. The signal conductor 10 is connected to the communication modem 104 via the signal line 103, and is grounded with a predetermined impedance such that the potential rise of the magnetic cores 3a and 3b does not cause a problem with respect to the power frequency. Further, the conductive wall 11 a provided on the upper surface 22 of the magnetic core 3 a is electrically connected to the conductive wall 11 b and the ground bridge 14. Other configurations are the same as those in FIG. 14 of the fifth embodiment.

  In this manner, the conductive walls 11a and 11b of the magnetic cores 3a and 3b are grounded via the holding band 13 formed of a conductor, thereby eliminating the need for wiring of the ground wire and connection work.

  As described above, according to the sixth embodiment, the same effect as in the first embodiment can be obtained, and the conductive walls 5a, 3b of the magnetic cores 3a, 3b can be provided via the holding band 13 formed of a conductor. By grounding 5b or the conductive walls 11a and 11b, there is no need for grounding wires and connection work, and the installation cost of the inductive coupling device can be reduced.

  As described above, the inductive coupling device of the power line carrier communication system according to the present invention is suitable for a device that does not require an insulating structure for the system voltage.

It is a perspective view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention. It is a perspective view which shows the other structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention. It is a perspective view which shows the other structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention. It is a figure which shows an example of the place where the inductive coupling device of the power line carrier communication system by Embodiment 1 of this invention is actually installed. It is a figure which shows the other example of the place where the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention is actually installed. It is a figure which shows the example of a calculation result of the electric potential distribution of a magnetic core at the time of installing an inductive coupling device on the grounding sheath of an underground power line. It is a figure which shows the example of a calculation result of the electric potential distribution of a magnetic core at the time of installing the inductive coupling device of the power line carrier communication system by Embodiment 1 of this invention on the earthing | grounding sheath of an underground power line. It is a figure which shows the example of a calculation result of the electrical potential distribution of a magnetic core at the time of installing the inductive coupling device of the power line carrier communication system by Embodiment 1 of this invention on the earthing | grounding sheath of an underground power line. It is a figure which shows the example of a calculation result of the electric potential distribution of a magnetic core at the time of installing the inductive coupling device of the power line carrier communication system by Embodiment 1 of this invention on the earthing | grounding sheath of an underground power line. It is a perspective view which shows the other structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 1 of this invention. It is a perspective view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 2 of this invention. It is a top view which shows the structure of the inductive coupling device of the power line carrier communication system by Embodiment 3 of this invention. It is a top view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 4 of this invention. It is a perspective view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 5 of this invention. It is a perspective view which shows the structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 6 of this invention. It is a perspective view which shows the other structure of the inductive coupling apparatus of the power line carrier communication system by Embodiment 6 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Inductive coupling device, 2 Power line, 3, 3a, 3b Magnetic core, 4a, 4b Gap material, 5, 5a, 5b, 11, 11a, 11b, 12, 12a, 12b Conductive wall, 6a, 6b Ground terminal, 7 Ground Wire, 8 connector case, 9 connector, 10 signal conductor, 13 holding band, 14, 14a, 14b grounding bridge, 20 aperture, 21 outer peripheral surface, 22 upper surface, 23 lower surface, 24 inner peripheral surface, 31 cable conductor, 32 insulator 33 Ground sheath, 34 Cable jacket, 41a, 41b Elastic body, 42a, 42b Holding plate, 43a, 43b Spring, 101 Overhead power line, 102 Utility pole, 103 Signal line, 104 Communication modem, 105 Transformer, 106 Underground power line , 108 terminal processing unit, 110 transformer lead line, 201 target axis, 202 equipotential line, 2 2,212 area.

Claims (15)

A magnetic core having an aperture for passing a power line as a primary winding;
A signal conducting wire as a secondary winding passed through the aperture,
An inductive coupling device for a power line communication system, wherein the magnetic core is installed on a ground sheath of a power line with a ground sheath, and the magnetic core is grounded.   2. The inductive coupling device for a power line communication system according to claim 1, wherein a conductive wall is provided on any surface except the inner peripheral surface of the magnetic core, and the conductive wall is grounded.   3. The inductive coupling device for a power line carrier communication system according to claim 2, wherein the conductive wall is electrically connected to a signal conductor grounded with a predetermined impedance.   3. The inductive coupling device for a power line carrier communication system according to claim 2, wherein the magnetic core is divided into a plurality in the axial direction of the power line, and each conductive wall provided in each magnetic core is grounded.   5. The power line carrier communication system according to claim 4, wherein the magnetic core is divided into a plurality of parts in the direction perpendicular to the axial direction of the power line, and the conductive walls provided in each magnetic core are connected by a ground bridge and grounded. Inductive coupling device.   5. The inductive coupling device for a power line carrier communication system according to claim 4, wherein an elastic body is attached to an inner wall of each magnetic core, and the elastic body is fixed to the power line by being in close contact with the power line.   5. The power line carrier according to claim 4, wherein a pressing plate is attached to an inner wall of each magnetic core via a spring, and the spring is compressed and the pressing plate is fixed to the power line by closely contacting the power line. An inductive coupling device for a communication system.   2. A holding band forming a loop smaller than a loop of a signal conducting wire that circulates around the magnetic core is passed through the aperture, and the end of the signal conducting wire and the holding band are mechanically connected to each other. Inductive coupling device of power line carrier communication system.   9. The power line carrier communication according to claim 8, wherein the holding band is formed of a conductor, is electrically connected to a conductive wall of the magnetic core, and is electrically connected to a signal conductor that is grounded with a predetermined impedance. Inductive coupling device of the system. A plurality of magnetic cores having an aperture for passing a power line as a primary winding and divided in the axial direction of the power line;
A signal lead as a secondary winding through the aperture;
An inductive coupling device for a power line carrier communication system, comprising a conductive wall provided on any surface except for the inner peripheral surface of each magnetic core and for grounding each magnetic core.   The inductive coupling device for a power line carrier communication system according to claim 10, wherein each conductive wall is electrically connected to a signal conductor grounded with a predetermined impedance.   The inductive coupling device of a power line carrier communication system according to claim 10, wherein an elastic body is attached to each inner wall of each magnetic core, and an inner diameter dimension of each elastic body is smaller than an outer diameter dimension of the power line.   11. The inductive coupling of a power line carrier communication system according to claim 10, wherein a pressing plate is attached to an inner wall of each magnetic core via a spring, and an inner diameter dimension of each pressing plate is smaller than an outer diameter dimension of the power line. apparatus.   A holding band passing through the aperture, the holding band forming a loop smaller than the loop of the signal conductor that circulates around the magnetic core, and mechanically connected to the end of the signal conductor. Item 11. An inductive coupling device for a power line carrier communication system according to Item 10.   15. The power line according to claim 14, wherein the holding band is formed of a conductor, is electrically connected to each conductive wall of each magnetic core, and is electrically connected to a signal conductor grounded with a predetermined impedance. Inductive coupling device for carrier communication system.

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