GALVANIC CORROSION SUPPRESSION METHOD, GROUNDING WIRE APPARATUS AND GROUNDING SYSTEM

Abstract

 Embodiments of the present invention provide a galvanic corrosion inhibition method, a ground cable apparatus, and a grounding system, and relate to the field of electronic technologies, resolving a problem that existing galvanic corrosion inhibition solutions have excessively high costs or a poor effect. The ground cable apparatus includes: an isolation and protection module and a first metallic device made of a first metal or a second metallic device made of a second metal, where one end of the isolation and protection module is equipotentially connected to the first metallic device, and the other end of the isolation and protection module is equipotentially connected to the second metallic device; when a potential difference between the first metallic device and the second metallic device is less than a preset switching voltage, the isolation and protection module is in an open-circuit state or in a high-impedance state; and when a potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state. The embodiments of the present invention are applied to galvanic corrosion inhibition.

Description

[0001] This application claims priority to Chinese Patent Application No. 201410605678.2, filed with the Chinese Patent Office on October 30, 2014, and entitled "GALVANIC CORROSION INHIBITION METHOD, GROUND CABLE APPARATUS, AND GROUNDING SYSTEM", which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present invention relates to the field of electronic technologies, and in particular, to a galvanic corrosion inhibition method, a ground cable apparatus, and a grounding system.

BACKGROUND

[0003] In electric power or communications, for ease of maintenance and wiring, one vertical passage for a person to climb down may be dug every other section of road, which is referred to as a manhole. Common manholes include a cable manhole, a communications manhole, and the like. Devices such as an outdoor communications device and a ground bar group embedded into a wall of a manhole are included in the manhole, where a housing of the device is connected to a grounding apparatus by using a ground cable, so that energy of lightning and a fault current can be transferred safely.

[0004] Because a manhole cannot drain, there is usually accumulated water in the manhole. If there is a potential difference between a metal potential of the device housing and a metal potential of the ground bar group, for example, the device housing is of a metallic aluminum Al material and a metal potential of the housing is -1.662 V, and the ground bar group is of a metallic copper Cu material and a metal potential of the ground bar group is +0.337 V. When there is a potential difference between the two metals and the metals are connected by using a conducting wire, galvanic corrosion occurs under a galvanic cell effect with water as an electrolyte. As shown in FIG. 1, Al as an anode loses an electron and is corroded.

[0005] In the prior art, a galvanic corrosion problem is resolved mainly by means of thickening an anti-corrosive coating or sacrificial anode protection. However, because a manhole is located underground, a device needs to be dragged out of the manhole during installation and maintenance, the anti-corrosive coating is prone to be damaged, and consequently, galvanic corrosion cannot be effectively resolved. For the sacrificial anode protection, a worker needs to perform anode replacement periodically, and therefore maintenance costs of the sacrificial anode protection are excessively high.

SUMMARY

[0006] The present invention provides a galvanic corrosion inhibition method, a ground cable apparatus, and a grounding system, so as to resolve a problem that existing galvanic corrosion inhibition solutions have excessively high costs or a poor effect.

[0007] To achieve the foregoing objectives, the following technical solutions are used in embodiments of the present invention:

[0008] According to a first aspect, a ground cable apparatus is provided, including an isolation and protection module and a first metallic device made of a first metal or a second metallic device made of a second metal, where a metal potential of the first metal is less than a metal potential of the second metal;
one end of the isolation and protection module is equipotentially connected to the first metallic device, and the other end of the isolation and protection module is equipotentially connected to the second metallic device;
when a potential difference between the first metallic device and the second metallic device is less than a preset switching voltage, the isolation and protection module is in an open-circuit state or in a high-impedance state, where the switching voltage is greater than a potential difference between the metal potential of the second metal and the metal potential of the first metal; or
when a potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state.

[0009] In a first possible implementation manner of the first aspect, the isolation and protection module is used for unidirectional isolation, and that one end of the isolation and protection module is equipotentially connected to the first metallic device, and the other end of the isolation and protection module is equipotentially connected to the second metallic device includes:

an isolation starting end of the isolation and protection module is equipotentially connected to the first metallic device made of the first metal, an isolation tail end of the isolation and protection module is equipotentially connected to the second metallic device made of the second metal, and a direction from the isolation starting end to the isolation tail end is a direction in which the isolation and protection module allows a current to flow.

[0010] In a second possible implementation manner of the first aspect, the isolation and protection module is used for bidirectional isolation, and when the potential difference between the second metallic device and the first metallic device is greater than or equal to a preset reverse switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state, where the switching voltage and the reverse switching voltage are conducting voltages in different current directions between the first metallic device and the second metallic device.

[0011] With reference to any one of the first aspect, the first possible implementation manner of the first aspect, and the second possible implementation manner of the first aspect, in a third possible implementation manner, the first metallic device is a device housing, and the second metallic device is a ground bar group; or the first metallic device is a ground bar group, and the second metallic device is a device housing.

[0012] With reference to the third possible implementation manner of the first aspect, in a fourth possible implementation manner, the first metal is metallic aluminum AL, and the second metal is metallic copper Cu.

[0013] With reference to any one of the first aspect and the first to fourth possible implementation manners of the first aspect, in a fifth possible implementation manner, the isolation and protection module includes at least one component of a thyristor surge suppressor TSS, a transient voltage suppressor TVS, a diode, a silicon controlled thyristor, and a field effect transistor.

[0014] With reference to any one of the first aspect and the first to fifth possible implementation manners of the first aspect, in a sixth possible implementation manner, the ground cable apparatus further includes an additional component; the additional component is parallelly connected to the isolation and protection module; and the additional component is configured to release at least one of energy generated during a lightning stroke, a fault current, static electricity, and electromagnetic noise.

[0015] With reference to the sixth possible implementation manner of the first aspect, in a seventh possible implementation manner, the additional component includes at least one component of a varistor, a gas discharge tube, the TVS, a resistor, a capacitor, and an invalidation protection component.

[0016] With reference to any one of the first aspect and the first to seventh possible implementation manners of the first aspect, in an eighth possible implementation manner, a value range of the switching voltage is 3 V to 24 V.

[0017] According to a second aspect, a grounding system is provided, including the ground cable apparatus according to any one of the first aspect and the first to eighth possible implementation manners of the first aspect, where the ground cable apparatus includes a first metallic device, and the first metallic device is made of a first metal; and
a second metallic device, where the second metallic device is made of a second metal, and a metal potential of the first metal is less than a metal potential of the second metal, where
the ground cable apparatus is connected to the second metallic device.

[0018] According to a third aspect, a ground cable system is provided, including a first metallic device made of a first metal; and
the ground cable apparatus according to any one of the first aspect and the first to eighth possible implementation manners of the first aspect, where the ground cable apparatus includes a second metallic device, and the second metallic device is made of a second metal; and a metal potential of the first metal is less than a metal potential of the second metal, where
the ground cable apparatus is connected to the first metallic device.

[0019] According to a fourth aspect, a galvanic corrosion inhibition method is provided, where a ground cable apparatus includes an isolation and protection module and a first metallic device made of a first metal or a second metallic device made of a second metal; one end of the isolation and protection module is equipotentially connected to the first metallic device, and the other end of the isolation and protection module is equipotentially connected to the second metallic device; and a metal potential of the first metal is less than a metal potential of the second metal; and
the method includes:

keeping the isolation and protection module of the ground cable apparatus being in an open-circuit state or in a high-impedance state when a potential difference between the first metallic device and the second metallic device is less than a preset switching voltage, where the switching voltage is greater than a potential difference between the metal potential of the second metal and the metal potential of the first metal; or

keeping the isolation and protection module of the ground cable apparatus being in a conducting state or in a low-impedance state when a potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, so that a current flows safely.

[0020] In a first possible implementation manner of the fourth aspect, when the potential difference between the second metallic device and the first metallic device is greater than or equal to a preset reverse switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state, where the switching voltage and the reverse switching voltage are conducting voltages in different current directions between the first metallic device and the second metallic device.

[0021] With reference to the fourth aspect or the first possible implementation manner of the fourth aspect, in a second possible implementation manner, the ground cable apparatus further includes an additional component, and the additional component is parallelly connected to the isolation and protection module; and
at least one of energy generated during a lightning stroke and a fault current, static electricity, and electromagnetic noise that are generated is released by the additional component of the ground cable apparatus.

[0022] With reference to any one of the fourth aspect, the first possible implementation manner of the fourth aspect, and the second possible implementation manner of the fourth aspect, in a third possible implementation manner, the first metallic device is a device housing, and the second metallic device is a ground bar group; or the first metallic device is the ground bar group, and the second metallic device is the device housing; and
a value range of the switching voltage is 3 V to 24 V.

[0023] According to the foregoing solutions, because one end of an isolation and protection module of a ground cable apparatus and a first metallic device are equipotential, and the other end of the isolation and protection module and a second metallic device are equipotential, a potential difference between the two ends of the isolation and protection module is also less than a preset switching voltage when a potential difference between the first metallic device and the second metallic device is less than the preset switching voltage. In this case, the isolation and protection module is in an open-circuit state or in a high-impedance state. In this way, because the switching voltage is greater than a potential difference between a metal potential of a second metal of which the second metallic device is made and a metal potential of a first metal of which the first metallic device is made, the isolation and protection module is in an open-circuit state or in a high-impedance state when the potential difference between the first metallic device and the second metallic device is equal to a difference between the metal potentials of the metals of which the first metallic device and the second metallic device are made, so that a current loop cannot be formed between the first metallic device and the second metallic device. This avoids generating a galvanic cell effect between the first metallic device and the second metallic device, and protects the first metallic device from being corroded. When the potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, for example, when the first metallic device generates a fault current or is struck by lightning, the isolation and protection module is in a conducting state or in a low-impedance state, so that a current flows safely, and the device is protected from being damaged.

[0024] From the above mentioned, the present invention can effectively inhibit galvanic corrosion, and the ground cable apparatus includes a conventional component by using a conventional technology. Therefore, costs for resolving a galvanic corrosion problem are reduced.

BRIEF DESCRIPTION OF DRAWINGS

[0025] To describe the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings required for describing the embodiments. Apparently, the accompanying drawings in the following description show merely some embodiments of the present invention, and a person of ordinary skill in the art may still derive other drawings from these accompanying drawings without creative efforts.

FIG. 1 is a schematic diagram of a principle of galvanic corrosion according to an embodiment of the present invention;

FIG. 2a is a schematic structural diagram of a ground cable apparatus according to an embodiment of the present invention;

FIG. 2b is a schematic structural diagram of another ground cable apparatus according to an embodiment of the present invention;

FIG. 3a is a schematic diagram of a connection between the ground cable apparatus shown in FIG. 2a and a second metallic device according to an embodiment of the present invention;

FIG. 3b is a schematic diagram of a connection between the ground cable apparatus shown in FIG. 2b and a first metallic device according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of an isolation and protection module for unidirectional isolation according to an embodiment of the present invention;

FIG. 5 is a schematic structural diagram of an isolation and protection module for bidirectional isolation according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of another isolation and protection module for bidirectional isolation according to an embodiment of the present invention;

FIG. 7a is a schematic structural diagram of another ground cable apparatus according to an embodiment of the present invention;

FIG. 7b is a schematic structural diagram of another ground cable apparatus according to an embodiment of the present invention;

FIG. 8 is a schematic flowchart of a galvanic corrosion inhibition method according to an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a grounding system according to an embodiment of the present invention; and

FIG. 10 is a schematic structural diagram of another grounding system according to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

[0026] The following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are merely some but not all of the embodiments of the present invention. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] In descriptions of the present invention, it should be understood that what is described in a sentence with a description manner of "a potential difference between a first ... and a second ..." is a potential difference obtained by subtracting a potential of the second ... from a potential of the first ..., but does not include a potential difference obtained by subtracting the potential of the first ... from the potential of the second ..., for example, "a potential difference between the first metallic device and the second metallic device" represents a potential difference obtained by subtracting a potential of the second metallic device from a potential of the first metallic device, and the forgoing manner is also applicable to sentences with a same description manner in the present invention.

[0028] An embodiment of the present invention provides a ground cable apparatus 20. The ground cable apparatus 20 includes an isolation and protection module 21 and a first metallic device 22 (shown in FIG. 2a) made of a first metal or a second metallic device 23 (shown in FIG. 2b) made of a second metal.

[0029] One end A of the isolation and protection module 21 is equipotentially connected to the first metallic device 22, and the other end B of the isolation and protection module 21 is equipotentially connected to the second metallic device 23, which is shown in FIG. 3a or FIG. 3b.

[0030] A metal potential of the first metal is less than a metal potential of the second metal.

[0031] When a potential difference between the first metallic device 22 and the second metallic device 23 is less than a preset switching voltage, the isolation and protection module 21 is in an open-circuit state or in a high-impedance state, where
the switching voltage is greater than a potential difference between the metal potential of the second metal and the metal potential of the first metal.

[0032] When the potential difference between the first metallic device 22 and the second metallic device 23 is greater than or equal to the switching voltage, the isolation and protection module 21 is in a conducting state or in a low-impedance state.

[0033] Optionally, the first metallic device is a device housing, and the second metallic device is a ground bar group; or the first metallic device is a ground bar group, and the second metallic device is a device housing.

[0034] Optionally, the first metal is metallic aluminum AL, and the second metal is metallic copper Cu.

[0035] It should be noted that the first metallic device is the partner which loses an electron and is corroded when a galvanic cell effect occurs, the first metallic device may be a device housing, or may be a ground bar group, and in a case in which only a galvanic cell effect occuring between the first metallic device and the second metallic device without an external current or voltage, a potential difference between the first metallic device and the second metallic device is equal to a potential difference between a metal potential of a metal of which the second metallic device is made and a metal potential of a metal of which the first metallic device is made. As shown in FIG. 1, a metal potential of metallic Al is less than a metal potential of metallic Cu, and when a galvanic cell effect occurs, the metallic Al as an anode loses an electron and is corroded, and the metallic Cu as a cathode obtains the electron and is protected. In this case, the metallic Al is used as a first metal, the metallic Cu is used as a second metal, and a potential difference between the anode and the cathode is a metal potential difference between the metallic Cu and the metallic Al.

[0036] In addition, both the connection between the isolation and protection module 21 and the first metallic device 22 and the connection between the isolation and protection module 21 and the second metallic device may be an equipotential connection performed by using OT terminals, that is, the end A of the isolation and protection module 21 may be connected to an OT terminal by using a conducting wire and connected to the first metallic device 22 by using the OT terminal. The other end B of the isolation and protection module 21 may also be connected to an OT terminal by using a conducting wire and connected to the second metallic device 23 by using the OT terminal.

[0037] The foregoing is only used for description by using an example. For example, the isolation and protection module 21 may also be connected to the first metallic device 22 or the second metallic device 23 in a manner in which a screw thread is in fit with a stud or a bolt, which is not limited in the present invention.

[0038] Optionally, the isolation and protection module 21 includes at least one component of a TSS (Thyristor Surge suppressor, thyristor surge suppressor), a TVS (Transient Voltage Suppressor, transient voltage suppressor), a diode, a silicon controlled thyristor, and a field effect transistor.

[0039] It should be noted that the TSS is also referred to as a solid-state discharge tube; and when an applied voltage of the TSS is lower than an off-state voltage of the TSS, the TSS is in an open-circuit state. When the applied voltage of the TSS exceeds the off-state voltage of the TSS, the TSS enters a conducting state due to a negative impedance effect. When an applied voltage of the TVS is lower than an off-state voltage of the TVS, the TSS is in a high-impedance state. When the applied voltage of the TVS exceeds the off-state voltage of the TVS, the TVS is in a low-impedance state.

[0040] In addition, when an applied voltage of the diode is lower than an off-state voltage of the diode, the diode is in a high-impedance state. When the applied voltage of the diode exceeds the off-state voltage of the diode, the diode is in an open-circuit state, the silicon controlled thyristor and the field effect transistor are similar, where when an applied voltage of the silicon controlled thyristor or the field effect transistor is lower than an off-state voltage of the silicon controlled thyristor or the field effect transistor, the silicon controlled thyristor or the field effect transistor is in an open-circuit state. When an applied voltage of the silicon controlled thyristor or the field effect transistor exceeds the off-state voltage of the silicon controlled thyristor or the field effect transistor, the silicon controlled thyristor or the field effect transistor is in a conducting state.

[0041] Optionally, the isolation and protection module 21 is used for unidirectional isolation, an isolation starting end of the isolation and protection module is equipotentially connected to the first metallic device 22, an isolation tail end of the isolation and protection module is equipotentially connected to the second metallic device 23, and a direction from the isolation starting end to the isolation tail end is a direction in which the isolation and protection module allows a current to flow.

[0042] Exemplarily, the first metal is Al, and the second metal is Cu, where a potential difference between a metal potential of Cu and a metal potential of Al is 0.337 V - (-1.662 V) = 1.999 V. The isolation and protection module is one TSS or n serially-connected TTSs, where n is a positive integer greater than 1. In this way, if the isolation and protection module includes one TSS, the switching voltage is an off-state voltage of the TSS, for example, 3 V. If the isolation and protection module includes the n serially-connected TTSs, as shown in FIG. 4, a direction in which the isolation and protection module allows a current to flow is a direction from an isolation starting end to an isolation tail end. In this case, the isolation starting end of the isolation and protection module is connected to the first metallic device, the isolation tail end of the isolation and protection module is connected to the second metallic device, and if the off-state voltage of the TSS is 3 V, the switching voltage of the isolation and protection module is 3n V.

[0043] Therefore, when there is no external voltage or current on the ground cable apparatus, the potential difference between the first metallic device and the second metallic device is 1.999 V. In this case, a potential difference between the end A (the isolation starting end) and the other end B (the isolation tail end) of the isolation and protection module is also 1.999 V and less than the off-state voltage 3 V of the TSS. Therefore, the isolation and protection module is in an open-circuit state, so that a current loop cannot be formed between the first metallic device and the second metallic device, which is equivalent to that a conducting wire in FIG. 1 is broken. This avoids generating a galvanic cell effect between the first metallic device and the second metallic device, and protects the first metallic device from being corroded. When the first metallic device generates a fault current or is struck by lightning to enable the potential difference between the first metallic device and the second metallic device to be greater than the switching voltage, the isolation and protection module is in a conducting state, so that a current flows safely, and the device is protected from being damaged.

[0044] In addition, the isolation and protection module may further include one TVS or n serially-connected TVSs. In this case, when a potential difference between the end A and the other end B of the isolation and protection module 21 is less than a preset switching voltage, the isolation and protection module 21 is in a high-impedance state. When the potential difference between the end A and the other end B is greater than or equal to the switching voltage, the isolation and protection module 21 is in a low-impedance state, and a working principle of the isolation and protection module 21 is the same as the above, which is not repeatedly described herein.

[0045] Optionally, the isolation and protection module 21 is used for bidirectional isolation, and when the potential difference between the first metallic device and the second metallic device is greater than or equal to a preset reverse switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state. The switching voltage and the reverse switching voltage are conducting voltages in different current directions between the first metallic device 22 and the second metallic device 23.

[0046] It should be noted that because a lightning stroke may be positive, or may be negative, when a device is struck by lightning, a current may be released in a direction from the first metallic device to the second metallic device, or a current may be released in a direction from the second metallic device to the first metallic device. Therefore, in a preferred implementation manner of the present invention, the isolation and protection module is used for bidirectional isolation, when a potential difference between the first metallic device and the second metallic device is greater than or equal to a preset switching voltage, or when a potential difference between the second metallic device and the first metallic device is greater than or equal to a preset reverse switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state. As shown in FIG. 5, two TSSs are parallelly connected reversely and then may be used as an isolation and protection module for bidirectional protection. Similarly, two TVSs are parallelly connected reversely, or a bidirectional protection effect may be achieved when one TSS and one TVS are parallelly connected reversely, which is not limited in the present invention.

[0047] In a possible implementation manner of this embodiment of the present invention, the isolation and protection module is a combination of symmetric or asymmetric diodes. As shown in FIG. 6, the isolation and protection module is formed by parallelly connecting two groups of serially-connected diodes reversely, where one group is formed by serially connecting N diodes, the other group is formed by serially connecting M diodes, and M may be equal to N, or may be unequal to N.

[0048] Exemplarily, N is equal to 5, M is equal to 3, and because an off-state voltage of a diode is 0.7 V, a switching voltage between the end A and the end B is 5 x 0.7 V = 3.5 V, and a reverse switching voltage between the end B and the end A is 3 x 0.7 V = 2.1 V. Therefore, referring to the foregoing descriptions, when the device neither generates a fault current nor is struck by lightning, a potential difference between the end A and the end B of the isolation and protection module is 1.999 V and is less than the switching voltage. In this case, both the two groups of serially-connected diodes are in a high-impedance state. This avoids generating a galvanic cell effect between the device housing and the ground bar group, and protects the device housing from being corroded. When the device generates a fault current or is struck by lightning, if a potential difference between the end A and the end B is greater than 3.5 V, a side on which N diodes are serially connected is open-circuit, and a side on which M diodes are serially connected is in a high-impedance state. In this case, a current may safely flow through the side on which the N diodes are serially connected. If a potential difference between the end B and the end A is greater than 2.1 V, the side on which the M diodes are serially connected is open-circuit, and the side on which the N diodes are serially connected is in a high-impedance state. In this case, a current may safely flow through the side on which the M diodes are serially connected, and the device is protected in a bidirectional way from being damaged.

[0049] It should be noted that when both the switching voltage and the reverse switching voltage are greater than the potential difference between the metal potential of the second metal and the metal potential of the first metal, either end of the isolation and protection module may be connected to the first metallic device, that is, the isolation and protection module 21 may be connected to the first metallic device 22 and the second metallic device 23 irrespective of directions.

[0050] In addition, the isolation and protection module may further include a silicon controlled thyristor or a field effect transistor, or may include a combination of multiple components of a TSS, a TVS, a diode, a silicon controlled thyristor, and a field effect transistor, which is not repeatedly described herein.

[0051] In a preferred embodiment of the present invention, a value range of the switching voltage is 3 V to 24 V.

[0052] Exemplarily, as shown in FIG. 6, because an off-state voltage of a diode is 0.7 V, a value range of N may be [5, 34], and a value range of a switching voltage of the isolation and protection module is [3.5, 23.8].

[0053] Further, as shown in FIG. 7a or FIG. 7b, the ground cable apparatus further includes an additional component 24, where the additional component 22 is parallelly connected to the isolation and protection module 21, and the additional component 24 is configured to release at least one of energy generated during a lightning stroke, a fault current, static electricity, and electromagnetic noise.

[0054] Optionally, the additional component 22 includes at least one component of a varistor, a gas discharge tube, a TVS, a resistor, a capacitor, and an invalidation protection component.

[0055] Specifically, to ensure that the ground cable apparatus can protect the device from being damaged by an overcurrent with ultra-high energy and generated during a lightning stroke and the like, the additional component may include the varistor or the gas discharge tube, assisting the isolation and protection module 21 in releasing an overcurrent. In addition, the additional component may further include the resistor or the capacitor configured to release static electricity or electromagnetic noise of the device. Moreover, to avoid that the device cannot be prevented, in a case in which the isolation and protection module 21 is damaged (for example, burnt or broken), from being struck by lightning, the additional component may further include the invalidation protection component, where when a potential difference between the device housing and the ground bar group reaches a preset threshold, the additional component is in a short-circuit state.

[0056] In this way, in a scenario in which galvanic corrosion occurs on a device housing in a manhole, the device housing is the first metallic device, a ground bar group is the second metallic device. According to the foregoing method, the device housing can be effectively protected from being corroded, and a person skilled in the art should clearly understand that this embodiment of the present invention is applicable to all scenarios in which galvanic corrosion occurs.

[0057] According to the foregoing ground cable apparatus, because one end of an isolation and protection module of the ground cable apparatus is equipotentially connected to a first metallic device, and the other end of the isolation and protection module is equipotentially connected to a second metallic device, a potential difference between the two ends of the isolation and protection module is also less than a preset switching voltage when a potential difference between the first metallic device and the second metallic device is less than the preset switching voltage. In this case, the isolation and protection module is in an open-circuit state or in a high-impedance state. In this way, because the switching voltage is greater than a potential difference between a metal potential of a second metal of which the second metallic device is made and a metal potential of a first metal of which the first metallic device is made, the isolation and protection module is in an open-circuit state or in a high-impedance state when the potential difference between the first metallic device and the second metallic device is equal to a difference between the metal potentials of the metals of which the first metallic device and the second metallic device are made, so that a current loop cannot be formed between the first metallic device and the second metallic device. This avoids generating a galvanic cell effect between the first metallic device and the second metallic device, and protects the first metallic device from being corroded. When the potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, for example, when the first metallic device generates a fault current or is struck by lightning, the isolation and protection module is in a conducting state or in a low-impedance state, so that a current flows safely, and the device is protected from being damaged.

[0058] From the above mentioned, this embodiment of the present invention can effectively inhibit galvanic corrosion, and the ground cable apparatus is constituted by a conventional component by using a conventional technology. Therefore, costs for resolving a galvanic corrosion problem are reduced.

[0059] An embodiment of the present invention provides a galvanic corrosion inhibition method. As shown in FIG. 8, a ground cable apparatus includes an isolation and protection module and a first metallic device made of a first metal or a second metallic device made of a second metal; one end of the isolation and protection module is equipotentially connected to the first metallic device made of the first metal, and the other end of the isolation and protection module is equipotentially connected to the second metallic device made of the second metal; and a metal potential of the first metal is less than a metal potential of the second metal. The method includes:

S801: keep the isolation and protection module of the ground cable apparatus being in an open-circuit state or in a high-impedance state when a potential difference between the first metallic device and the second metallic device is less than a preset switching voltage, where the switching voltage is greater than a potential difference between the metal potential of the second metal and the metal potential of the first metal.

S802: keep the isolation and protection module of the ground cable apparatus being in a conducting state or in a low-impedance state when the potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, so that a current flows safely.

[0060] Optionally, when the potential difference between the second metallic device and the first metallic device is greater than or equal to a reverse switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state.

[0061] Optionally, the ground cable apparatus further includes an additional component, where the additional component is parallelly connected to the isolation and protection module; and at least one of energy generated during a lightning stroke and a fault current, static electricity, and electromagnetic noise that are generated is released by the additional component of the ground cable apparatus.

[0062] Optionally, the first metallic device is a device housing, and the second metallic device is a ground bar group; or the first metallic device is the ground bar group, and the second metallic device is the device housing; and a value range of the switching voltage is [3 V, 24 V].

[0063] It should be noted that the method is executed by the ground cable apparatus 20 in the apparatus embodiments, all steps of the method correspond to functional modules of the ground cable apparatus 20. For the method steps described above, refer to corresponding processes in the foregoing apparatus embodiments, which are not repeatedly described herein.

[0064] According to the foregoing method, because one end of an isolation and protection module of a ground cable apparatus and a first metallic device are equipotential, and the other end of the isolation and protection module and a second metallic device are equipotential, a potential difference between the two ends of the isolation and protection module is also less than a preset switching voltage when a potential difference between the first metallic device and the second metallic device is less than the preset switching voltage. In this case, the isolation and protection module is in an open-circuit state or in a high-impedance state. In this way, because the switching voltage is greater than a potential difference between a metal potential of a second metal of which the second metallic device is made and a metal potential of a first metal of which the first metallic device is made, the isolation and protection module is in an open-circuit state or in a high-impedance state when the potential difference between the first metallic device and the second metallic device is equal to a difference between the metal potentials of the metals of which the first metallic device and the second metallic device are made, so that a current loop cannot be formed between the first metallic device and the second metallic device. This avoids generating a galvanic cell effect between the first metallic device and the second metallic device, and protects the first metallic device from being corroded. When the potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, for example, when the first metallic device generates a fault current or is struck by lightning, the isolation and protection module is in a conducting state or in a low-impedance state, so that a current flows safely, and the device is protected from being damaged.

[0065] In addition, for brief description, the foregoing method embodiment is described as a combination of a series of actions, but a person skilled in the art should understand that the present invention is not limited by a sequence of described actions, and a person skilled in the art shall should also understand that the embodiments described in this specification are preferred embodiments, and actions and modules involved are not mandatory for the present invention.

[0066] An embodiment of the present invention provides a grounding system 90. As shown in FIG. 9, the grounding system 90 includes the ground cable apparatus 20 shown in FIG. 2a, where the ground cable apparatus 20 includes a first metallic device made of a first metal. For details about the ground cable apparatus 20, refer to the descriptions corresponding to FIG. 2a in the apparatus embodiments, which is not repeatedly described herein; and
a second metallic device 91, where the second metallic device 91 is made of a second metal, and a metal potential of the first metal is less than a metal potential of the second metal, where
the ground cable apparatus 20 is connected to the second metallic device 91.

[0067] By using the foregoing grounding system, in the grounding system, because one end of an isolation and protection module of a ground cable apparatus and a first metallic device are equipotential, and the other end of the isolation and protection module and a second metallic device are equipotential, a potential difference between the two ends of the isolation and protection module is also less than a preset switching voltage when a potential difference between the first metallic device and the second metallic device is less than the preset switching voltage. In this case, the isolation and protection module is in an open-circuit state or in a high-impedance state. In this way, because the switching voltage is greater than a potential difference between a metal potential of a second metal of which the second metallic device is made and a metal potential of a first metal of which the first metallic device is made, the isolation and protection module is in an open-circuit state or in a high-impedance state when the potential difference between the first metallic device and the second metallic device is equal to a difference between the metal potentials of the metals of which the first metallic device and the second metallic device are made, so that a current loop cannot be formed between the first metallic device and the second metallic device. This avoids generating a galvanic cell effect between the first metallic device and the second metallic device, and protects the first metallic device from being corroded. When the potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, for example, when the first metallic device generates a fault current or is struck by lightning, the isolation and protection module is in a conducting state or in a low-impedance state, so that a current flows safely, and the device is protected from being damaged.

[0068] An embodiment of the present invention provides a grounding system 100. As shown in FIG. 10, the grounding system 100 includes a first metallic device 101 made of a first metal; and
the ground cable apparatus 20 shown in FIG. 2b, where the ground cable apparatus 20 includes a second metallic device made of a second metal, and a metal potential of the first metal is less than a metal potential of the second metal. For details, refer to the descriptions corresponding to FIG. 2b in the apparatus embodiments, which is not repeatedly described herein.

[0069] The ground cable apparatus 20 is connected to the first metallic device 101.

[0070] According to the foregoing grounding system, in the grounding system, because one end of an isolation and protection module of a ground cable apparatus and a first metallic device are equipotential, and the other end of the isolation and protection module and a second metallic device are equipotential, a potential difference between the two ends of the isolation and protection module is also less than a preset switching voltage when a potential difference between the first metallic device and the second metallic device is less than the preset switching voltage. In this case, the isolation and protection module is in an open-circuit state or in a high-impedance state. In this way, because the switching voltage is greater than a potential difference between a metal potential of a second metal of which the second metallic device is made and a metal potential of a first metal of which the first metallic device is made, the isolation and protection module is in an open-circuit state or in a high-impedance state when the potential difference between the first metallic device and the second metallic device is equal to a difference between the metal potentials of the metals of which the first metallic device and the second metallic device are made, so that a current loop cannot be formed between the first metallic device and the second metallic device. This avoids generating a galvanic cell effect between the first metallic device and the second metallic device, and protects the first metallic device from being corroded. When the potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, for example, when the first metallic device generates a fault current or is struck by lightning, the isolation and protection module is in a conducting state or in a low-impedance state, so that a current flows safely, and the device is protected from being damaged.

[0071] The foregoing descriptions are merely specific embodiments of the present invention, but are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention shall fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A ground cable apparatus, comprising an isolation and protection module and a first metallic device made of a first metal or a second metallic device made of a second metal, wherein a metal potential of the first metal is less than a metal potential of the second metal;
one end of the isolation and protection module is equipotentially connected to the first metallic device, and the other end of the isolation and protection module is equipotentially connected to the second metallic device;
when a potential difference between the first metallic device and the second metallic device is less than a preset switching voltage, the isolation and protection module is in an open-circuit state or in a high-impedance state, wherein the switching voltage is greater than a potential difference between the metal potential of the second metal and the metal potential of the first metal; or
when a potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state.

2. The ground cable apparatus according to claim 1, wherein the isolation and protection module is unidirectional isolation, and that one end of the isolation and protection module is equipotentially connected to the first metallic device, and the other end of the isolation and protection module is equipotentially connected to the second metallic device comprises:

an isolation starting end of the isolation and protection module is equipotentially connected to the first metallic device made of the first metal, an isolation tail end of the isolation and protection module is equipotentially connected to the second metallic device made of the second metal, and a direction from the isolation starting end to the isolation tail end is a direction in which the isolation and protection module allows a current to flow.

3. The ground cable apparatus according to claim 1, wherein the isolation and protection module is used for bidirectional isolation, and when the potential difference between the second metallic device and the first metallic device is greater than or equal to a preset reverse switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state, wherein the switching voltage and the reverse switching voltage are conducting voltages in different current directions between the first metallic device and the second metallic device.

4. The ground cable apparatus according to any one of claims 1 to 3, wherein
the first metallic device is a device housing, and the second metallic device is a ground bar group; or the first metallic device is a ground bar group, and the second metallic device is a device housing.

5. The ground cable apparatus according to claim 4, wherein the first metal is metallic aluminum AL, and the second metal is metallic copper Cu.

6. The ground cable apparatus according to any one of claims 1 to 5, wherein the isolation and protection module comprises at least one component of a thyristor surge suppressor TSS, a transient voltage suppressor TVS, a diode, a silicon controlled thyristor, and a field effect transistor.

7. The ground cable apparatus according to any one of claims 1 to 6, wherein the ground cable apparatus further comprises an additional component; the additional component is parallelly connected to the isolation and protection module; and the additional component is configured to release at least one of energy generated during a lightning stroke, a fault current, static electricity, and electromagnetic noise.

8. The ground cable apparatus according to claim 7, wherein the additional component comprises at least one component of a varistor, a gas discharge tube, the TVS, a resistor, a capacitor, or an invalidation protection component.

9. The ground cable apparatus according to any one of claims 1 to 8, wherein
a value range of the switching voltage is 3 V to 24 V

10. A grounding system, comprising the ground cable apparatus according to any one of claims 1 to 9, wherein the ground cable apparatus comprises a first metallic device, and the first metallic device is made of a first metal; and
a second metallic device, wherein the second metallic device is made of a second metal, and a metal potential of the first metal is less than a metal potential of the second metal, wherein
the ground cable apparatus is connected to the second metallic device.

11. A grounding system, comprising a first metallic device made of a first metal; and
the ground cable apparatus according to any one of claims 1 to 9, wherein the ground cable apparatus comprises a second metallic device, and the second metallic device is made of a second metal; and a metal potential of the first metal is less than a metal potential of the second metal, wherein
the ground cable apparatus is connected to the first metallic device.

12. A galvanic corrosion inhibition method, wherein a ground cable apparatus comprises an isolation and protection module and a first metallic device made of a first metal or a second metallic device made of a second metal; one end of the isolation and protection module is equipotentially connected to the first metallic device, and the other end of the isolation and protection module is equipotentially connected to the second metallic device; and a metal potential of the first metal is less than a metal potential of the second metal; and
the method comprises:

keeping the isolation and protection module of the ground cable apparatus being in an open-circuit state or in a high-impedance state when a potential difference between the first metallic device and the second metallic device is less than a preset switching voltage, wherein the switching voltage is greater than a potential difference between the metal potential of the second metal and the metal potential of the first metal; or

keeping the isolation and protection module of the ground cable apparatus being in a conducting state or in a low-impedance state when a potential difference between the first metallic device and the second metallic device is greater than or equal to the switching voltage, so that a current flows safely.

13. The method according to claim 12, wherein when the potential difference between the second metallic device and the first metallic device is greater than or equal to a preset reverse switching voltage, the isolation and protection module is in a conducting state or in a low-impedance state, wherein the switching voltage and the reverse switching voltage are conducting voltages in different current directions between the first metallic device and the second metallic device.

14. The method according to claim 12 or 13, wherein the ground cable apparatus further comprises an additional component, and the additional component is parallelly connected to the isolation and protection module; and
at least one of energy generated during a lightning stroke and a fault current, static electricity, and electromagnetic noise that are generated is released by the additional component of the ground cable apparatus.

15. The method according to any one of claims 12 to 14, wherein the first metallic device is a device housing, and the second metallic device is a ground bar group; or the first metallic device is the ground bar group, and the second metallic device is the device housing; and
a value range of the switching voltage is 3 V to 24 V.

Drawing