Corrosion rate measuring device for electric wires and method for measuring the same
The electrochemical impedance measurement device allows for precise in situ corrosion rate assessment of overhead power lines by stabilizing electrolyte contact and preventing leakage, addressing the challenge of measuring corrosion rates on installed wires.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- RAILWAY TECHNICAL RESEARCH INSTITUTE
- Filing Date
- 2024-11-28
- Publication Date
- 2026-06-09
AI Technical Summary
Existing methods fail to accurately measure the corrosion rate of overhead power lines in situ, particularly for stranded wires, which is crucial for proper maintenance and management.
An electrochemical impedance measurement device with a probe container and stopper member is used to apply an electrolyte and electrical signal to the power line, allowing in situ measurement of corrosion rate by impedance analysis.
Enables accurate, non-destructive measurement of corrosion rate on overhead power lines, even when installed, by ensuring stable electrolyte contact and preventing leakage, thus maintaining the integrity of the measurement.
Smart Images
Figure 2026093603000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to an apparatus and method for electrochemically measuring the corrosion rate of overhead power lines in situ. [Background technology]
[0002] Electrical wires, such as trolley wires and feeder wires, are made of metal materials such as copper and aluminum. Over time, these wires corrode, reducing their strength and conductivity, and increasing their electrical resistance. When this happens, an insulating film is formed on the surface of the wire by corrosion products such as oxides and compounds. For example, in the case of copper wires, as corrosion progresses, a colored insulating film made of verdigris is produced, and the state of corrosion can be visually confirmed to some extent. On the other hand, in the case of aluminum wires, even when corrosion progresses, they only become slightly blackened, and the state of corrosion cannot be determined from their appearance. Therefore, a method for electrically determining the corrosion state of electrical wires has been proposed.
[0003] For example, Patent Document 1 discloses a method for measuring the electrical resistance of electric wires such as trolley wires and feeder wires, which have an insulating film formed by corrosion products, by applying low and high voltages with a depth probe. The resistance of the electric wire being measured is measured at low and high voltages. If the resistance is zero at both voltages, it is determined that corrosion is not progressing. Conversely, if the resistance is infinite at low voltage and above a certain level even at high voltage, it is determined that the corrosion is extensive. [Prior art documents] [Patent Documents]
[0004] [Patent Document 1] Japanese Patent Publication No. 2006-258775 [Overview of the project] [Problems that the invention aims to solve]
[0005] Incidentally, as electrical wires corrode, they thin, so for the proper maintenance and management of overhead power lines, it is necessary to understand not only the degree of corrosion but also the corrosion rate. Generally, the corrosion rate of metals is measured by preparing test specimens and conducting exposure tests, but it was desirable to evaluate the corrosion rate of overhead power lines while they were still installed.
[0006] The present invention has been made in view of the above circumstances, and its purpose is to provide an apparatus and method for electrochemically measuring the corrosion rate of overhead power lines in situ, and in particular, an apparatus and method for electrochemically measuring the corrosion rate of stranded overhead power lines in situ. [Means for solving the problem]
[0007] The corrosion rate measuring device according to the present invention is a device for measuring the corrosion rate of an overhead electric wire, wherein the external opening of a through hole that penetrates a probe container containing an electrolyte is positioned on the surface of the measuring portion of the electric wire, and an electrical signal is applied between the electric wire and a counter electrode immersed in the electrolyte to perform impedance measurement, wherein the probe container includes a projection having the external opening at its protruding tip, with the through hole formed along its axis, and a stopper member made of an elastic material having a through hole of a known inner diameter is fitted into the external opening so as to connect the through hole and the through hole, and the opening of the through hole is positioned along the surface of the measuring portion to perform the measurement.
[0008] With these features, it becomes possible to bring an electrolyte solution into contact with an overhead power line over a known area and to apply an electrical signal between the electrolyte solution and the power line, thereby enabling the electrochemical measurement of the power line corrosion rate in situ.
[0009] In the invention described above, the inside of the probe container may be sealed except for the external opening, and the stopper member may be fitted into the external opening to hold the electrolyte without leakage to the outside. With this feature, the electrolyte can be easily brought into contact with and placed on the electric wire, and the corrosion rate of overhead electric wires can be measured electrochemically in situ.
[0010] In the invention described above, the plug member may be a columnar body having the through hole along its central axis, and the plug member may protrude from the external opening. With this feature, even if the electric wire is installed overhead, the electrolyte can be easily brought into contact with and placed on it, and the corrosion rate of the electric wire can be measured electrochemically in place.
[0011] The invention described above may be characterized by including a fixing jig for fixing the probe container to the electric wire with the opening of the through hole positioned along the surface of the measuring section. With this feature, even if the electric wire is suspended overhead, the electrolyte can be easily and stably brought into contact with and placed on it, and the corrosion rate of the electric wire can be measured electrochemically in place.
[0012] The present invention relates to a method for measuring the corrosion rate of an overhead electric wire, wherein the external opening of a through-hole penetrating a probe container containing an electrolyte is positioned on the surface of the measuring portion of the electric wire, and an electrical signal is applied between the electric wire and a counter electrode immersed in the electrolyte to perform impedance measurement, wherein the probe container includes a projection with the through-hole formed along its axis and having the external opening at its protruding tip, and a stopper member made of an elastic material having a through-hole of a known inner diameter is fitted into the external opening so as to connect the through-hole and the through-hole, and the opening of the through-hole is positioned along the surface of the measuring portion to perform the measurement.
[0013] With these features, it becomes possible to bring an electrolyte solution into contact with an overhead power line over a known area and to apply an electrical signal between the electrolyte solution and the power line, thereby enabling the electrochemical measurement of the power line corrosion rate in situ.
[0014] In the invention described above, the probe container may have a second external opening for containing the electrolyte inside, and after fitting the stopper member into the external opening, the electrolyte may be injected into the interior from the second external opening, and then the second external opening may be sealed. Alternatively, the inside of the probe container may be sealed except for the external opening, and the electrolyte may be held without leaking to the outside when the stopper member is fitted into the external opening. With such features, even overhead power lines can be easily brought into contact with and placed on them, and the corrosion rate of the power lines can be measured electrochemically in place.
[0015] In the invention described above, the probe container may be fixed to the electric wire with the opening of the through-hole positioned along the surface of the measuring section. Alternatively, the probe container may be fixed to the electric wire without changing the inner diameter of the through-hole. With such features, even if the electric wire is suspended overhead, the electrolyte can be easily and stably brought into contact with and placed on it, and the corrosion rate of the electric wire can be measured electrochemically in place. [Brief explanation of the drawing]
[0016] [Figure 1] This is a block diagram of a corrosion measuring device according to the present invention. [Figure 2] This is a side view of the probe container of a corrosion measuring device. [Figure 3] This is a photograph of the external appearance of the protruding part of the probe container. [Figure 4] This is a cross-sectional view of the stopper member. [Figure 5]This is a photograph showing a probe container fixed to an electric wire with a fixing jig. [Figure 6] This is a Nyquist diagram obtained by measuring an outdoor-exposed electric wire by the electrochemical impedance method. [Figure 7] This is a Nyquist diagram obtained by measuring an indoor-stored electric wire by the electrochemical impedance method.
Embodiments for Carrying Out the Invention
[0017] Hereinafter, an electric wire corrosion rate measuring apparatus according to the present invention and a measuring method using the same apparatus will be described with reference to FIGS. 1 to 5. First, the corrosion rate measuring apparatus will be described.
[0018] As shown in FIG. 1, a measuring apparatus 1 which is a corrosion rate measuring apparatus is an electrochemical measuring apparatus that measures the corrosion rate of an electric wire 5 such as an overhead wire to be measured by bringing an electrolytic solution E into contact with the electric wire 5 using a probe container 10. That is, the measuring apparatus 1 measures the impedance by applying an electric signal between a measuring part 5a of the electric wire 5 serving as a working electrode and a counter electrode immersed in the electrolytic solution E.
[0019] The measuring apparatus 1 includes a probe container 10 that houses the electrolytic solution E, a measuring part 20, and a control part 23 including a personal computer or the like connected to the measuring part 20. The measuring part 20 includes an AC generator 21 and a potential holder 22, and its operation is controlled by the control part 23. The control part 23 transmits a control signal to the measuring part 20, receives the output from the measuring part 20, performs necessary calculations, and also serves as an image display device or the like that displays information regarding the measurement result.
[0020] One pole for applying a voltage of the measuring part 20 is connected to an electrode 15 (see FIG. 2) of the probe container 10, and the other pole is connected to a terminal 24. The terminal 24 is configured to be able to be connected to the electric wire 5, and for example, an alligator clip can be preferably used.
[0021] In the measurement unit 20, the AC generator 21 can generate an AC signal that serves as the input wave as an electrical signal, while simultaneously measuring and recording the potential of the response wave. Furthermore, the potential holder 22 can control the voltage of the weak AC signal applied by the AC generator 21 to minimize the chemical state change of the measurement unit 5a before and after measurement, keeping it constant even with respect to changes in hydrogen ion concentration. This allows the measurement unit 20 to operate and impedance measurement to be performed.
[0022] Referring also to Figure 2, the probe container 10 has a through-hole 11 that penetrates the container, and the electrolyte E can be contained inside. The through-hole 11 is formed along the axis of the probe container 10. In other words, the probe container 10 is tubular due to the through-hole 11, and has a projection 12 extending downward, a counter electrode insertion part 13 extending laterally, and an electrolyte inlet 14 extending upward from the projection 12, and as a whole it has a roughly T-shape.
[0023] The probe container 10 has an external opening 12a that opens outward at the protruding tip of the protruding portion 12, and a second external opening 14a that opens outward at the end of the electrolyte inlet 14. The external opening 12a is an opening for bringing the electrolyte E into contact with the electric wire 5, and it is preferable that the tip has elasticity to prevent leakage of the electrolyte E, and the attachment of an elastic member that extends the external opening 12a downward is considered. In this embodiment, a stopper member 3 made of an elastic material is fitted into the external opening 12a. Details of the stopper member 3 will be described later. The second external opening 14a of the electrolyte inlet 14 is provided with a sealing stopper 14b. The sealing and opening of the second external opening 14a can be operated by attaching and removing the sealing stopper 14b.
[0024] The counter electrode insertion section 13 has its end sealed and is provided so that the counter electrode 15 is immersed in the electrolyte and protrudes into the inside of the probe container 10. In detail, a substantially cylindrical resin stopper 13b is fixed to the opening 13a of the counter electrode insertion section 13, keeping the opening 13a sealed at all times. Furthermore, a needle-shaped electrode 15 is provided that penetrates the resin stopper 13b from the outside to the inside of the probe container 10, and the electrode 15 protrudes into the inside of the probe container 10. The electrode 15 is made of a material that will not be corroded by the electrolyte E. For example, Pt can be suitably used as the material for the electrode 15.
[0025] The stopper member 3 is a substantially columnar body provided with a through-hole 31 that communicates with the through-hole 11 of the probe container 10, and opens the electrolyte E contained in the probe container 10 to the outside. The stopper member 3 is designed to prevent the electrolyte E from leaking to the outside when the through-hole 31 is pressed against the measuring portion 5a of the electric wire 5 and the opening 31a at the lower end of the through-hole 31 (see Figure 4) is positioned along the surface of the electric wire 5. In particular, it is preferable that the stopper member 3 is attached so as to protrude downward from the external opening 12a of the probe container 10, thereby making it easier to prevent leakage of the electrolyte E by ensuring that only the stopper member 3, which is made of an elastic material, comes into contact with the electric wire 5 when the probe container 10 is pressed against the surface of the electric wire 5.
[0026] Referring to Figure 3, for example, the stopper member 3 can prevent leakage of the electrolyte E by providing an umbrella-shaped sealing portion 32 around the opening 31a of the through hole 31. In other words, by making the sealing portion 32 tightly contact the electric wire 5 around the opening 31a of the through hole 31, it is possible to prevent the formation of gaps through which the electrolyte E can leak.
[0027] As shown in Figure 4, the plug member 3 is provided with a through hole 31 of a known inner diameter along the central axis A. The contact portion 32 of the plug member 3 is umbrella-shaped around the opening 31a below the through hole 31. Furthermore, it is preferable that the contact portion 32 is curved such that the lower surface 33 that contacts the electric wire 5 is positioned lower as it moves outward from the central axis A. It is also preferable that the axial thickness of the contact portion 32 is reduced as it moves outward. In other words, it is preferable that the contact portion 32 has a roughly suction cup shape. This allows the contact portion 32 to be made to adhere well to the electric wire 5 when the plug member 3 is pressed against the electric wire 5, and leakage of the electrolyte E can be easily prevented.
[0028] In this way, the plug member 3 adheres closely to the surface of the electric wire 5, defining the area of the measuring portion 5a by the inner diameter of the through hole 31 (the inner diameter of the opening 31a). Since the area of the measuring portion 5a is used to calculate the corrosion rate, it is preferable that an accurate value be obtained. For this reason, it is preferable that the plug member 3 does not change the inner diameter of the opening 31a of the through hole 31 so as to keep the area of the measuring portion 5a constant when pressed against the surface of the electric wire 5. In particular, the umbrella-shaped contact portion 32 is designed to adhere well to the electric wire 5 by easily deforming in the axial direction, which is the direction in which it is pressed against the electric wire 5, and is also thickened in the radial direction to suppress radial deformation of the opening 31a and maintain its dimensions.
[0029] By the way, when the probe container 10 is sealed except for the external opening 12a (sealing the second external opening 14a of the electrolyte inlet 14 and the opening 13a of the counter electrode insertion part 13), it is preferable that the inner diameter of the through hole 31 be small enough to hold the electrolyte E without leakage even when the external opening 12a is facing downwards. In other words, leakage of the electrolyte E is prevented by the surface tension of the electrolyte E. This makes it easy to place the probe container 10 on the electric wire 5. Also, by making the inner diameter of the through hole 31 small, even if the measuring part 5a is set on a surface with a relatively large curvature on its outer circumference, such as the strands of a stranded wire, when the opening 31a is brought into contact with it, the stopper member 3 surrounds the measuring part 5a without any gaps, making it easy to accurately define the area of the measuring part 5a.
[0030] On the other hand, a relatively large inner diameter of the through-hole 31 that defines the area of the measuring section 5a is preferable because it allows for a larger area of the measuring section 5a, thereby relatively reducing the measurement error. The inner diameter of the through-hole 31 is set considering these balances. In this embodiment, the inner diameter of the through-hole 31 was set to Φ2 mm.
[0031] As shown in Figure 5, the measuring device 1 may also preferably include a fixing jig 4 for fixing the probe container 10 to the electric wire 5. The fixing jig 4 is, for example, a clamp, which can fix the probe container 10 to the electric wire 5 with the opening 31a of the through hole 31 positioned along the surface of the measuring section 5a.
[0032] Next, a method for measuring the corrosion rate of the electric wire 5 using the measuring device 1 will be described.
[0033] First, the stopper member 3 is fitted into the external opening 12a of the probe container 10, then the electrolyte E is injected through the second external opening 14a, and the second external opening 14a is sealed with the sealing stopper 14b. The opening 13a of the counter electrode insertion part 13 is always sealed. The stopper member 3 has a through hole 31, but as described above, it can hold the electrolyte E without leakage from the opening 31a.
[0034] Next, the probe container 10 is installed on the overhead wire 5. At this time, the external opening 12a of the protruding portion 12 is positioned on the surface of the wire 5. That is, the opening 31a of the plug member 3 is positioned along the surface of the wire 5, and the electrolyte E held in the probe container 10 comes into contact with the measuring portion 5a. The measuring portion 5a is the area in contact with the electrolyte E, and its area is defined by the opening 31a. By maintaining the radial dimensions of the opening 31a, the precise area of the measuring portion 5a can be ensured. It is preferable to use the fixing jig 4 when installing the probe container 10 on the wire 5.
[0035] Furthermore, the measuring unit 20 of the measuring device 1 (see Figure 1) is connected to the electrode 15 of the probe container 10 and the electric wire 5. The electric wire 5 is connected using the terminal 24. In this way, the following connections are made in order from the measuring unit 20: electrode 15 (counter electrode), electrolyte E, measuring unit 5a (working electrode), electric wire 5, terminal 24, and measuring unit 20, forming a circuit. If the electric wire 5 is severely corroded and has a thick insulating coating, it is desirable to polish the area on the surface of the electric wire 5 where the terminal 24 is connected using a wire brush or similar tool to ensure conductivity.
[0036] Then, the control unit 23 operates the AC generator 21 and the potential holder 22 of the measurement unit 20 to apply the aforementioned weak AC signal to the circuit while changing its frequency, and measures the impedance of the circuit including the measurement unit 5a using the electrochemical impedance method to measure the corrosion rate of the electric wire 5. In this measurement, since a weak AC signal is used, the change in the state of the measurement unit 5a can be kept small, so even when used on an overhead electric wire 5, it has almost no effect on the continued use of the electric wire 5.
[0037] Since the electrochemical impedance method is well known, a detailed explanation will be omitted here. Briefly, the Nyquist diagram is obtained from the real and imaginary components of the impedance obtained by the measurement unit 20, and the solution resistance R sol (Ω), charge transfer resistance R ct (Ω), Electrical double layer capacitance C dl (F) of which charge transfer resistance R ct We will find the charge transfer resistance R. ct This value represents the difficulty of electron transfer reactions occurring in the measurement section 5a, and therefore the charge transfer resistance R ct The corrosion rate of the electric wire 5 can be calculated from this.
[0038] As described above, the electrochemical measurement method using the measuring device 1 allows for the contact of an electrolyte E over a known area onto an overhead wire 5 and the application of an electrical signal between the electrolyte E and the wire 5. Therefore, the corrosion rate of the wire 5 can be measured electrochemically in situ.
[0039] [Examples] The following describes the results of actually obtaining the charge transfer resistance R ct and measuring the corrosion rate using FIGS. 6 and 7.
[0040] [Measurement Results (1)] As shown in FIG. 6, for the overhead wire exposed outdoors while being overhead, impedance measurement was performed by the measuring device 1 to obtain a Nyquist diagram. From this Nyquist diagram, the charge transfer resistance R ct was found to be approximately 9000 Ω. Then, using this charge transfer resistance R ct , when the amount of zinc corrosion per year was determined as the zinc corrosion rate, it was 0.18 mm / year. Since the overhead wire is a stranded wire of zinc-plated steel, using the physical property values of zinc (molar mass 65.4 (g / mol), density 7.12×10 -3 (g / mm 3 )) and setting the corrosion rate conversion constant to 0.013 (V), the zinc corrosion rate was calculated.
[0041] [Measurement Results (2)] As shown in FIG. 7, for the overhead wire stored indoors, impedance measurement was performed by the measuring device 1 to obtain a Nyquist diagram. From this Nyquist diagram, the charge transfer resistance R ct was found to be approximately 16000 Ω. Then, using this charge transfer resistance R ct , when the zinc corrosion rate was determined, it was 0.10 mm / year. Comparing with the overhead wire exposed outdoors shown in Measurement Results (1), it was found that the zinc corrosion rate was smaller. That is, the wire exposed outdoors and corroded had a faster corrosion rate than the wire stored indoors and with less corrosion progress.
[0042] As described above, representative embodiments of the present invention and modifications associated therewith have been described, but the present invention is not necessarily limited thereto and can be appropriately changed by those skilled in the art. That is, those skilled in the art will be able to find various alternative embodiments and modification examples without departing from the scope of the appended claims.
Explanation of Reference Numerals
[0043] 1. Measuring device 3 Plug member 5 Electric wire 5a Measuring part 10 Probe container 11 Through hole 12a External opening 15 electrodes 20 Measurement section 23 Control Unit 31 Through-holes E Electrolyte
Claims
1. A device for measuring the corrosion rate of overhead power lines, This electrochemical measuring device measures impedance by applying an electrical signal between the electric wire and a counter electrode immersed in the electrolyte, with the external opening of a through-hole penetrating a probe container containing an electrolyte positioned on the surface of the measuring portion of the electric wire. The device for measuring the corrosion rate of electric wires is characterized in that the probe container includes a projection having an external opening at its tip, with the through hole formed along the axis, a plug member made of an elastic material having a through hole of a known inner diameter is fitted into the external opening so as to connect the through hole and the through hole, and the opening of the through hole is positioned along the surface of the measuring part to perform the measurement.
2. The corrosion rate measuring device for electric wires according to claim 1, characterized in that the inside of the probe container is sealed except for the external opening, and the stopper member is fitted into the external opening to hold the electrolyte without leakage to the outside.
3. The wire corrosion rate measuring device according to claim 1, characterized in that the plug member is a columnar body having the through hole along its central axis, and the plug member protrudes from the external opening.
4. The wire corrosion rate measuring device according to claim 1, characterized in that it includes a fixing jig for fixing the probe container to the wire while the opening of the through hole is positioned along the surface of the measuring section.
5. A method for measuring the corrosion rate of overhead power lines, This electrochemical measurement method involves placing the external opening of a through-hole penetrating a probe container containing an electrolyte solution on the surface of the measuring portion of the electric wire, and applying an electrical signal between the electric wire and a counter electrode immersed in the electrolyte solution to perform impedance measurement. A method for measuring the corrosion rate of an electric wire, characterized in that the probe container includes a projection having an external opening at its protruding tip and a through hole formed along its axis, a plug member made of an elastic material having a through hole of a known inner diameter is fitted into the external opening so as to connect the through hole and the through hole, and the opening of the through hole is positioned along the surface of the measuring part to perform the measurement.
6. The method for measuring the corrosion rate of an electric wire according to claim 5, characterized in that the probe container has a second external opening for containing the electrolyte inside, the plug member is fitted into the external opening, the electrolyte is injected into the interior from the second external opening, and then the second external opening is sealed.
7. The method for measuring the corrosion rate of an electric wire according to claim 6, characterized in that the inside of the probe container is sealed except for the external opening, and the electrolyte is held in place without leakage to the outside when the stopper member is fitted into the external opening.
8. The method for measuring the corrosion rate of an electric wire according to claim 5, characterized in that the probe container is fixed to the electric wire with the opening of the through hole positioned along the surface of the measuring section.
9. The method for measuring the corrosion rate of an electric wire according to claim 8, characterized in that the probe container is fixed to the electric wire without changing the inner diameter of the through hole.