Railway equipment protection system
The railway facility protection system addresses the inadequacies of existing methods by using a power protector, isolation transformer, and series circuit with fuses to suppress voltage and interrupt ground fault currents, effectively safeguarding wayside equipment and power facilities from ground faults.
Patent Information
- Application Number
- JP2024100576
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-06-21
- Publication Date
- 2026-01-08
AI Technical Summary
Existing railway equipment protection systems, such as the flashover conductor and protective ground wire methods, fail to effectively protect wayside equipment from ground faults, particularly at bushings where no conductors are installed, and are insufficient to handle voltage rises above 2.5 kV, leading to equipment failure.
A railway facility protection system comprising a power protector, isolation transformer, first and second protectors, resistor, and fuse, which suppress voltage rises and interrupt ground fault currents through a series circuit, ensuring dielectric breakdown prevention and fuse activation to prevent damage.
The system effectively protects wayside equipment and remote power facilities from ground faults with a simple configuration and low cost, preventing damage and reducing the spread of fault currents.
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Abstract
Description
[Technical Field]
[0001] The present disclosure relates to railway equipment protection systems. [Background technology]
[0002] In electric railways, ground faults can occur in substations and electric rail tracks, which are the equipment that supplies power to trains, due to lightning strikes, flying objects, birds, small animals, fallen trees, etc. When a ground fault occurs, the ground fault current flows out to the ground, is absorbed from the ground into the rails, and returns to the substation. When this happens, the potential at the ground fault point rises significantly, and the rail potential also rises over a wide area (in opposite phase to the ground fault point). Figure 1 shows the rise in potential and the flow of current when a ground fault (ground fault) occurs in a power feeder circuit. While such ground faults do not affect the substation, they can cause malfunctions in equipment installed along the line.
[0003] Now, referring to Figure 2, we will discuss burnout of wayside equipment. Figure 2 is a diagram for explaining burnout of wayside equipment due to a ground fault. In Figure 2, a ground fault occurs in 20kV equipment (feeder circuit switchgear, etc.) located along the way. Because the potential at the ground fault point rises significantly, a large potential difference occurs between the ground fault point and the distant ground, and a potential difference also occurs between the ground fault point and the power equipment and control lines that supply power. As a result, part of the ground fault current flows via the power lines and control lines toward the ground of the distant power equipment or equipment, burning the equipment. Therefore, the burnout does not occur only in the equipment at the ground fault point, but extends over a wide area.
[0004] Currently, the flashover conductor method and the protective ground wire method are used to protect equipment from such ground faults. Figure 3 is a diagram explaining the flashover conductor method. The flashover conductor method aims to protect the insulators that insulate the contact wires from flashover. As shown in Figure 3, a conductor is wound between the high-voltage insulation and the negative insulation of the insulator, and this conductor is connected to the negative feeder (NF) in BT electrified sections and to the AT protection wire (PW) in AT electrified sections. If an insulator flashover occurs in this system, the ground fault current flows through the ground fault conductor to the NF and returns to the substation, activating the substation fault detection relay and opening the substation circuit breaker, thereby protecting the insulator.
[0005] Figure 4 is a diagram explaining the protective ground wire system (FW system). The protective ground wire system (FW system) is used in stations and depots where installing flashover conductors is complicated. A protective ground wire (FW) is installed on the support to be protected (such as a utility pole) and connected to the negative feeder (NF) via a power protector. When a ground fault occurs on the support to be protected, the power protector discharges due to the rise in potential at the ground fault point, and the fault current returns to the substation from the NF via the power protector, thereby significantly suppressing the ground fault current flowing into the ground. [Prior art documents] [Patent documents]
[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-193035 [Non-patent literature]
[0007] [Non-Patent Document 1] "Development of a Power Protector with Follow-Current Suppression for AC Feeder Circuits," PP1493-1499, IEEEJ Trans. IA, Vol. 126, No. 11, 2006 Summary of the Invention [Problem to be solved by the invention]
[0008] However, in the case of the flashover conductor system, as shown in Figure 5 (a diagram showing the unprotectable pattern in the flashover conductor system), it does not function to protect against flashovers at bushings of wayside equipment where no flashover conductor is installed. Therefore, if a ground fault occurs in equipment that is not protected, the ground-fault current cannot be returned to the negative conductor (NF), and a fault like that shown in Figure 2 occurs.
[0009] In the case of the protective ground wire system, as shown in Figure 6 (a diagram showing protection failure pattern 1 in the protective ground wire system), it does not function to protect against flashovers at bushings (equipment not connected to FW) on wayside equipment. This causes the fault shown in Figure 2. Also, Figure 7 (a diagram showing protection failure pattern 2 in the protective ground wire system) shows a case where the protected equipment is within the protection range of the power protector. Even in such a case, the AC discharge inception voltage of the power protector is generally around 2.5 kV, which is insufficient to protect the wayside equipment. In other words, the protected equipment cannot withstand up to 2.5 kV, and so the equipment will fail.
[0010] In view of such circumstances, the present disclosure proposes a new method for protecting wayside equipment and remote power supply facilities and other equipment connected to the wayside equipment from ground faults. [Means for solving the problem]
[0011] In order to solve the above-described problems, the present disclosure provides, as an example, a railway facility protection system that protects railway facilities from ground faults, comprising: a power protector connected to the railway equipment and configured to suppress a voltage rise due to a ground fault to a predetermined value; an isolation transformer provided between a power supply facility that supplies AC power to the railway facility and the railway facility; a first protector that is provided between the control line of the railway equipment and the Class A ground of the railway equipment and discharges when a predetermined voltage that is suppressed by the power protector is applied; A resistor provided in the control line; a fuse provided after the resistor; A second protector is provided between the rear stage of the fuse and a remote ground that is provided at a predetermined distance or more from the Class A ground, and discharges when a predetermined voltage value suppressed by the power protector is applied, the isolation transformer prevents dielectric breakdown between the primary side and the secondary side of the isolation transformer by its withstand voltage; We propose a railway equipment protection system in which the first protector discharges when a predetermined voltage suppressed by the power protector is applied, and the current resulting from this discharge propagates through the resistor, the fuse, and the second protector, causing the fuse to blow as the current flows through it.
[0012] Further features related to the present disclosure will become apparent from the description and accompanying drawings of this specification, and aspects of the present disclosure may be realized and realized by the elements and combinations of various elements and aspects set forth in the following detailed description and the appended claims. The descriptions herein are exemplary and illustrative only and are not intended to limit the scope or application of the present disclosure in any way. [Effects of the Invention]
[0013] According to the technology of the present disclosure, it is possible to protect wayside equipment and remote power supply facilities and other equipment connected to the wayside equipment from ground faults with a simple configuration and at low cost. [Brief explanation of the drawings]
[0014] [Figure 1] FIG. 1 is a diagram showing the state of potential rise and current flow when a ground fault (ground fault accident) occurs in a feeding circuit. [Figure 2] FIG. 10 is a diagram for explaining burnout of wayside equipment due to a ground fault. [Figure 3] FIG. 10 is a diagram for explaining a flashover conductor method. [Figure 4] FIG. 1 is a diagram for explaining a protection field wire system (FW system). [Figure 5] FIG. 10 is a diagram showing a non-protectable pattern in the flashover conductor method. [Figure 6] FIG. 10 is a diagram showing a protection-unavailable pattern 1 in the protection line system. [Figure 7] FIG. 10 is a diagram showing a protection unavailability pattern 2 in the protection line system. [Figure 8] 1 is a diagram showing an example of the schematic configuration of a ground fault protection system (also called a "railway facility protection system") 100 according to the present embodiment. [Figure 9] FIG. 10 is a diagram showing the flow of current from the wayside device 101 to the class A grounding 302 and the negative feeder (NF) when a ground fault occurs. [Figure 10] 10 is a diagram for explaining the protective action on the insulating transformer 201 side. FIG. [Figure 11] FIG. 10 is a diagram for explaining the protective effect on the control line 210 side. [Figure 12] FIG. 2 is a diagram showing a test circuit for a ground fault simulation test. [Figure 13] 10 is a table showing the results of a contact line ground fault simulation test. [Figure 14] FIG. 10 is a diagram showing waveforms in a ground fault simulation test. DETAILED DESCRIPTION OF THE INVENTION
[0015] Hereinafter, embodiments and examples of the present disclosure will be described with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements may be designated by the same numerals. Note that the accompanying drawings show specific embodiments and implementation examples in accordance with the principles of the present disclosure, but these are intended to aid in understanding the present disclosure and are by no means to be used to interpret the present disclosure in a limiting manner.
[0016] Although the present embodiment has been described in sufficient detail to enable those skilled in the art to implement the present disclosure, it should be understood that other implementations and forms are possible, and that changes in configuration and structure and substitutions of various elements are possible without departing from the scope and spirit of the technical ideas of the present disclosure. Therefore, the following description should not be interpreted as being limited thereto.
[0017] <Example of ground fault protection system configuration> FIG. 8 is a diagram showing an example of the schematic configuration of a ground fault protection system (also called a "railway facility protection system") 100 according to this embodiment.
[0018] The ground fault protection system 100 is a system for protecting railway facilities including wayside equipment 101 from ground faults, and includes the wayside equipment 101, a power protector 102, and a protector panel 200. The protector panel 200 includes an isolation transformer 201 having a primary side connected to a remote power supply facility 301 and a secondary side connected to the wayside equipment 101 to supply AC power to the wayside equipment 101, a shielding layer 202 provided between the primary winding and secondary winding of the isolation transformer 201, an insulating plate 203 provided under the housing of the isolation transformer 201, at least one protector A204 connected to a control line 210 leading to a control circuit (not shown) that controls the wayside equipment 101, at least one resistor 205 provided on the control line 210, at least one fuse 206 provided on the control line 210 and connected in series with the resistor 205, at least one protector B207 connected to the control line 210, and a relay 208 provided in a part of the control line 210.
[0019] One terminal of the wayside equipment 101 is connected to the trolley wire, and the other terminal is grounded to the Class A grounding 302 and is also connected to the negative feeder (NF) via the power protector 102. The action of the power protector 102 can suppress the rise in ground potential of the wayside equipment 101 in the event of a ground fault to about 2.5 kV.
[0020] In the protector panel 200, the shield layer 202 of the insulating transformer 201 and the protector B 207 are grounded to the distant earth 209. The class A ground 302 and the distant earth 209 are provided at a distance of 10 m or more. This is to increase the potential difference between the class A ground 302 and the distant earth 209, thereby increasing the current flowing through the fuse 206 and improving the melting efficiency of the fuse 206, as well as to prevent the influence of a rise in the potential of the class A ground 302 in the event of a ground fault (if the potential of the distant earth rises, there is a risk of a fault occurring on the control circuit side).
[0021] In addition, the protector panel 200 is configured so that an insulating state is ensured between the wayside equipment 101 and the remote power supply facility 301 by an insulating transformer 201 and an insulating plate 203 on the AC power supply side of the wayside equipment 101. Furthermore, on the control circuit side, a DC voltage is applied (an insulating transformer configuration cannot be adopted), so a series circuit that interrupts the ground fault current is configured, consisting of protector A 204, protector B 207, resistor (resistor group) 205, and fuse (fuse group) 206.
[0022] Relay 208 is connected to the output of a portion of fuse (fuse group) 206, and operates to change the ground fault detection contact from conductive to open, or from open to conductive, when fuse (fuse group) 206 melts due to a ground fault. When relay 208 operates the ground fault detection contact, remote monitoring device 304 detects the operation of the ground fault detection contact, i.e., the blowing of fuse 206.
[0023] <Operation when a ground fault occurs> 9 to 11 are diagrams for explaining the operation of the ground fault protection system 100 when a ground fault occurs. Fig. 9 is a diagram showing the flow of current from the wayside device 101 to the class A grounding 302 and the negative feeder (NF) when a ground fault occurs. Fig. 10 is a diagram for explaining the protective action on the insulating transformer 201 side. Fig. 11 is a diagram for explaining the protective action on the control line 210 side.
[0024] (1) Figure 9 As shown in FIG. 9, when a ground fault (dielectric breakdown) occurs between the trolley wire and the housing of the wayside equipment 101 (see (i)), a ground-fault current flows from the housing of the wayside equipment 101 to the class A grounding 302 (see (ii)), and the ground potential of the class A grounding 302 rises (for example, to about 10 kV: see (iii)). Furthermore, the rise in the ground potential of the class A grounding 302 generates a potential difference between the terminals of the power protector 102, i.e., between the class A grounding 302 and the negative feeder (NF), and the power protector 102 discharges, causing a ground-fault current to flow (see (iv)). Then, a ground-fault current flows from the housing of the wayside equipment 101 to the power protector 102 to the NF to the substation. This action causes the maximum potential rise of the housing of the wayside equipment 101 to become equal to the discharge start voltage (for example, 2.5 kV) of the power protector 102 (see (v)).
[0025] (2) Figure 10 By the operation of the power protector 102, the potential difference occurring between the housing of the wayside equipment 101 and the remote power supply equipment 301 and the remote earth 209 is suppressed to the above-mentioned 2.5 kV or less (see (vi)). When such a potential difference occurs, the withstand voltage of the insulating transformer 201 (e.g., AC 10 kV or more) prevents dielectric breakdown between the primary and secondary sides of the insulating transformer 201, and the withstand voltage of the insulating plate 203 (e.g., AC 3 kV or more) prevents dielectric breakdown between the housing / shield layer 202 of the insulating transformer 201 and the housing of the protector panel 200 (see (vii)). This prevents a ground-fault current from flowing to the primary side of the insulating transformer 201 and prevents a rise in the ground potential of the remote earth 209.
[0026] (3) Figure 11 When a ground fault current occurs, protector A 204 and protector B 207 are activated, and the ground fault current flows in the following path: casing of wayside equipment 101 → protector A 204 → resistor 205 → fuse 206 → protector B 207 → remote ground 209. At this time, the current flowing through fuse 206 (with an interruption characteristic of, for example, 300 A when 3 kV is applied) is suppressed to approximately 90 A or less by the series resistor (e.g., 30 Ω) 205 and the potential difference between the casing of wayside equipment 101 and remote ground 209 (2.5 kV) / 30 Ω of series resistor 205 (see (viii)). When the ground fault current (current suppressed to approximately 90 A or less) flows through each fuse 206, each fuse 206 melts and interrupts the ground fault current (see (ix)). This prevents the ground fault current from flowing to the control circuit side.
[0027] Furthermore, when each fuse 206 blows, a relay (ground fault detection contact) 208 operates, and outputs a ground fault detection (fuse blown) signal to a remote device such as a monitoring device.
[0028] The resistor 205 (e.g., 30 Ω) is provided to prevent a large current that exceeds the breaking capacity of the fuse 206 from flowing through the fuse, which would otherwise prevent the fuse 206 from blowing. For this reason, it is necessary to use resistor 205 with a resistance value that can suppress the ground fault current to a current value that allows the fuse 206 to break. For example, when using a small fuse with a rated current of 2 A, a resistance value of 30 Ω or more is suitable. When using a fuse with high breaking capacity, it is possible to suppress the resistance value to less than 30 Ω, but there is a concern that larger fuses will result in larger ground fault protection systems.
[0029] <Effects of the embodiment> According to this embodiment, it is possible to prevent dielectric breakdown between the housing and internal circuitry of wayside equipment (railway facilities) in the event of a ground fault, thereby reducing the risk of damage to the wayside equipment. It is also possible to prevent damage to distant power supply facilities and other equipment connected to the wayside equipment, thereby suppressing the spread of damage. [Example]
[0030] A ground fault simulation test was carried out to confirm the protective effect of the ground fault protection system according to this embodiment.
[0031] Figure 12 shows a test circuit for a ground fault simulation test. In Figure 12, component 1201 corresponds to protector panel 200 in Figure 8, the application of 6000 V AC corresponds to ground fault voltage generation (i) in Figure 9, power No. 2 follow-on current suppression G-type 1203 corresponds to power protector 102 in Figure 8, and wayside device simulation 1204 corresponds to wayside device 101 in Figure 8. To simulate a ground fault, two VCBs are turned on. To activate the power protectors, the switch of power No. 2 follow-on current suppression G-type 1203 is turned on. In this simulation test, the synergistic effect of the combination of protector panel 200, which provides a current interruption function (e.g., by a fuse), and power protector 102 is confirmed by the presence or absence of ground fault voltage application and the activation of power No. 2 follow-on current suppression G-type 1203.
[0032] Figure 13 is a table showing the results of the overhead contact line ground fault simulation test. In Figure 13, test numbers 1 and 2 show the results when the power protector was activated, and test number 3 shows the results when the power protector was not activated.
[0033] In Test No. 1 and Test No. 2, power supply No. 2 discharged simultaneously with the VCB closing, which simulated a ground fault. At the same time, current also flowed through the fuse on the control circuit side. This was because the discharge start voltage of power supply No. 2 was AC 2.5kV, and the control circuit protection safety device, which has a lower discharge start voltage, operated. The fuse blew in 13ms to 15ms, and no abnormalities occurred in the DC 100V power supply, which simulates lineside equipment, or the relay. This result means that power supply No. 2 alone was insufficient to protect the control circuit, and that the fuse was effective in interrupting the ground fault current that was diverted to the control circuit side.
[0034] As mentioned above, Test No. 1 and Test No. 2 were tests on a circuit that combined a power protector (power No. 2) and a fuse, and their protective effect was confirmed. Next, when a test was conducted without power No. 2, the fuse and the resistor (30 Ω) inserted in series with the fuse burned out and were unable to cut off the current. This result shows that a fuse alone is not sufficient to protect the control circuit, and that it is essential to use it in conjunction with a power protector (power No. 2).
[0035] On the other hand, no abnormalities were found in the DC 100V power supply of the lineside equipment simulation 1204 in any of the test numbers. This is due to the effect of the isolation transformer inserted on the primary side of the DC 100V power supply bearing the 2.5kV increase in potential.
[0036] Figure 14 shows the waveforms of a ground fault simulation test. Figure 14(a) shows the power supply voltage and current waveforms, and Figure 14(b) shows the fuse voltage and current waveforms. Figures 14(a) and (b) show that the waveforms are stable after the VCB is turned on (when the ground fault occurs) and the fuse blows.
[0037] The technology described in this embodiment is not inherently related to any specific device and can be implemented by combining components. Various types of general-purpose devices can also be added. A dedicated device may be constructed to perform the functions of this embodiment and each example. Various functions can also be formed by appropriately combining multiple components disclosed in this embodiment and each example. For example, some components may be omitted from all the components shown in the embodiment and each example, or components from different examples may be appropriately combined.
[0038] Although specific embodiments are described in this disclosure, they are in all respects illustrative and not limiting, and it will be understood by those skilled in the art that there are numerous combinations of hardware and firmware suitable for implementing the technology of this disclosure.
[0039] Furthermore, in the above-described embodiments and examples, the control lines and information lines are those that are considered necessary for explanation, and not all control lines and information lines in the product are necessarily shown. All components may be interconnected.
[0040] In addition, other implementations of the present disclosure will be apparent to those skilled in the art from consideration of the present embodiments and examples. The specification and examples are exemplary only, with the scope and spirit of the technology of the present disclosure being indicated by the following claims. [Explanation of symbols]
[0041] 100 Earth Fault Protection System 101 Lineside equipment 102 Power protector 200 Safety device board 201 Isolation transformer 202 Shield Layer 203 Insulating board 204 Protector A 205 Resistance 206 Fuse 207 Protector B 208 Relay 209 Distant grounding 210 Control Line 301 Remote power supply equipment 302 Class A grounding 303 Remote Equipment 304 Remote Monitoring Device
Claims
1. A railway equipment protection system that protects railway equipment from ground faults, comprising: a power protector connected to the railway equipment and configured to suppress a voltage rise due to a ground fault to a predetermined value; an isolation transformer provided between a power supply facility that supplies AC power to the railway facility and the railway facility; a first protector that is provided between the control line of the railway equipment and the Class A ground of the railway equipment and discharges when a predetermined voltage that is suppressed by the power protector is applied; A resistor provided in the control line; a fuse provided after the resistor; a second protector that is provided between the rear stage of the fuse and a remote ground that is provided at a distance greater than a predetermined distance from the Class A ground, and that discharges when a predetermined voltage that is suppressed by the power protector is applied; the isolation transformer prevents dielectric breakdown between the primary side and the secondary side of the isolation transformer by its withstand voltage; A railway equipment protection system in which the first protector discharges when a predetermined voltage suppressed by the power protector is applied, and the current caused by the discharge propagates through the resistor, the fuse, and the second protector, and the fuse melts when the current flows through the fuse.
2. In claim 1, the isolation transformer is grounded to the remote ground; an insulating plate provided under a housing of the isolation transformer; a shielding layer provided between the isolation transformer and the insulating plate, The insulating plate prevents dielectric breakdown between the housing of the isolation transformer and the shielding layer due to the withstand voltage of the insulating plate, thereby preventing current due to the ground fault from flowing to the primary side of the isolation transformer and preventing an increase in the ground potential of the remote ground. This is a railway equipment protection system.
3. In claim 1 or 2, The resistor has a resistance value that suppresses the current caused by the ground fault to a current value that can be interrupted by the fuse.
4. In claim 3, The fuse has a rated current of 2 A, The resistor has a resistance value of 30 Ω or more.
5. In claim 2, The AC withstand voltage of the insulating transformer is 10 kV or more, The insulating plate has an AC withstand voltage of 3 kV or more.
6. In claim 1, A railway equipment protection system, wherein the remote grounding is at least 10 m away from the Class A grounding.
7. In claim 1, The first protector, the second protector, the resistor, and the fuse form a series circuit.
8. In claim 1, a relay provided in a subsequent stage of the fuse in the control line; When the fuse blows, the relay is activated, thereby enabling an external monitoring device to detect that the protection function of the railway equipment has been activated.
Citation Information
Patent Citations
Failure spotting system, method, program and computer readable record medium
JP2006193035A