JP7116582B2 - FAILURE LOCATION DEVICE, FAILURE POINT LOCATION SYSTEM AND FAILURE POINT LOCATION METHOD - Google Patents

Description

The present invention relates to a failure point locating device, a failure point locating system, and a failure point locating method.

Electric power for operation in an electric railway system is fed from a substation to vehicles via overhead lines, and returned to the substation via return lines such as rails.
Faults that occur in feeder circuits of electric railway systems include short-circuit faults in which overhead lines come into direct contact with rails, and ground faults in which electrical circuits such as overhead lines come into contact with structures such as contact line support poles.

When a short-circuit fault occurs, a large current exceeding the rating flows in the feeder circuit, which may cause failure of equipment such as transformers and circuit breakers. In addition, the route of the fault current caused by a ground fault is significantly different from that during normal operation, and if the fault current continues to flow out, delays in responding to the fault may cause further damage to surrounding structures and field equipment. Therefore, when a fault current occurs, it is necessary to take measures such as stopping power supply from the substation and stopping running trains.

Conventionally, overcurrent relays, DC high-speed circuit breakers, and ΔI fault selection relays have been used to detect fault currents associated with short-circuit faults and ground faults in DC feeding circuits.
These devices are installed at a substation and constantly measure the amount of change in the feeding current in the overhead line within a certain period of time to determine the occurrence of a failure in the overhead line to which power is supplied from the substation. When a fault current is detected, the DC high-speed circuit breaker is opened to cut off the feeding current (fault current).

Various failure point locating methods have been proposed for identifying the point where a failure has occurred in order to quickly recover from the failure when the failure is detected. For example, as described in Patent Document 1, when a fault occurs in an overhead wire supplied from two substations, a method of determining the failure point from the distribution ratio of the fault current flowing through the overhead wire of each substation. It has been known.

JP-A-2002-40087

When applying the technology described in Patent Document 1, it is necessary to accurately synchronize the fault current measurement times at the two substations. That is, the technology described in Patent Document 1 is based on the assumption that the distribution ratio of the current values measured at the two substations at the same time is obtained. Affects estimation accuracy. In particular, when a fault occurs immediately after a fault occurs or when the fault is near a substation, the amount of current fluctuation is steep, so there is a possibility that even a slight noise component or measurement time error may greatly affect the position estimation accuracy.
In addition, in the case of the prior art, it was necessary to measure the fault current at at least two substations, and it was theoretically impossible to estimate the point where the fault occurred with only one substation.

It is an object of the present invention to provide a fault locating device, a fault locating system, and a fault locating method capable of solving the above-described problems and precisely detecting the occurrence point of a fault due to a short circuit, ground fault, or the like. aim.

In order to solve the above problems, for example, the configurations described in the claims are adopted.
The present application includes a plurality of means for solving the above-mentioned problems, but to give an example, when estimating a fault point, which is the position where a fault occurs in the overhead wire of a DC electric railway, the transmission voltage of the substation and an acquisition unit that acquires the feeding current or rail potential of the overhead line, and the feeding current or rail potential obtained at at least two different measurement times based on a calculation formula that estimates the time variation of the fault current at the time of fault occurrence. An arithmetic processing unit that derives the distance from the substation to the fault point using the measured value, and a transmission unit that transmits information on the position of the fault point derived by the arithmetic processing unit. Here, the arithmetic processing unit collates the estimated distances from the substation to the fault point derived from at least two different substations, and derives the position where the estimated distances match as the fault point.

ADVANTAGE OF THE INVENTION According to this invention, the generation|occurrence|production point of the fault current by a short circuit, a ground fault, etc. can be detected with high precision.
Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a configuration diagram of a fault location system according to a first embodiment of the present invention; FIG. 1 is a block diagram showing a hardware configuration example of a failure detection device and a failure point locating device according to a first embodiment of the present invention; FIG. 4 is a flow chart showing an example of processing for detecting whether or not a failure has occurred according to the first embodiment of the present invention; FIG. 5 is a characteristic diagram showing an example of current change when a failure occurs according to the first embodiment of the present invention; 4 is a flow chart showing an example of fault location processing according to the first embodiment of the present invention; 1 is a configuration diagram when a fault location system according to a first embodiment of the present invention is applied to a plurality of substations; FIG. FIG. 10 is a diagram explaining an example of deriving the position of a fault point from the distances to the fault point derived by a plurality of fault point locating devices (an example in which the ranges of the derived distances match); FIG. 10 is a diagram illustrating an example of deriving the position of a fault point from the distances to the fault point derived by a plurality of fault point locating devices (an example in which ranges of derived distances overlap); FIG. 4 is a diagram illustrating an example of deriving the position of a fault point from the distances to the fault point derived by a plurality of fault point locating devices (an example in which the ranges of the derived distances do not overlap); FIG. 4 is a configuration diagram showing a modification of the fault location system according to the first embodiment of the present invention (at the time of detecting a short circuit fault); FIG. 11 is a configuration diagram of a fault location system according to a second embodiment of the present invention; FIG. 10 is a flow chart showing an example of processing for detecting whether or not a failure has occurred according to the second embodiment of the present invention; FIG. FIG. 11 is a flow chart showing an example of fault location processing according to the second embodiment of the present invention; FIG.

<1. First Embodiment>
A first embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 10. FIG.
[1-1. Configuration of fault location system]
FIG. 1 shows the overall configuration of a fault location system for estimating a fault current occurrence point such as a ground fault or a short circuit fault in a railway system.

As shown in FIG. 1, a substation 103 that supplies electric power to a vehicle 102 via an overhead wire 101 and a rail 104 that serves as a return line for the current supplied from the substation 103 is provided. The electric power supplied from the substation 103 to the vehicle 102 is direct current.
The substation 103 includes an ammeter 105 for measuring the current supplied from the substation 103 to the overhead line 101, a voltmeter 106 for measuring the voltage sent out from the substation 103, and a power supply from the substation 103 to the overhead line 101. and a circuit breaker 107 that cuts off the supply. Furthermore, the substation 103 is equipped with a failure detection device 108 that detects whether or not a failure has occurred based on the feeding current detected by the ammeter 105 . The failure detection device 108 interrupts the circuit breaker 107 when detecting the occurrence of failure.

The fault detection device 108 is connected to the fault location device 110 via the network 111 . The failure point locating device 110 performs arithmetic processing for estimating the failure point based on the information transmitted from the failure detection device 108, and locates the failure point. The failure point locating device 110 is also connected to the substation 103 via the network 111 .
The failure point locating information obtained by the failure point locating device 110 is transmitted to the alarm device 112, and the alarm device 112 notifies the occurrence of the failure and the information of the failure point that occurred.

The failure detection device 108 determines whether there is a failure in the feeder circuit based on the current value of the overhead wire measured by the ammeter. When the failure detection device 108 detects that a failure has occurred, the circuit breaker 107 cuts off the power supply to the corresponding overhead wire. Further, the failure detection device 108 transmits the current value and the voltage value measured within a certain period of time before and after the failure of the feeding circuit is detected to the failure point locating device 110 via the network 111 .

The failure point locating device 110 performs arithmetic processing for estimating the failure point of the feeding circuit based on the current value and voltage value transmitted by the failure detection device 108 . The details of the process of estimating the failure point will be described later. After estimating the failure point, the failure point locating device 110 transmits the location information of the failure point to the alarm device 112 .

As the information transmitted from the failure point locating device 110 to the alarm device 112, in addition to the location information of the failure point, information regarding the failure may be added. The information to be given may include, for example, the failure detection time, the measured current value, the voltage value, and the failure occurrence factor and failure event type (ground fault, short circuit, etc.) estimated from the measured values.

Note that FIG. 1 shows a state in which one vehicle (set) 102 is on the line in the power transmission section from the substation 103, but there is no vehicle 102 in the corresponding section, or there are a plurality of vehicles 102 may be on-line. Further, the configuration of the feeder circuit of the overhead line 101 may be double-wire feeder or parallel feeder.
The failure detection device 108 is provided for each overhead wire 101 to which power is supplied from the substation 103 and detects occurrence of a failure in the overhead wire 101 .

A network 111 is a facility for communication between the substation 103 and the fault detection device 108 and the fault location device 110 . The network 111 is configured by wired communication using electric wires, optical fibers, or the like, for example. Alternatively, the network 111 is configured by wireless communication using space waves or the like. In addition, the ammeter 105 and the voltmeter 106 installed along the line are directly connected to the substation 103 and the failure detection device 108, and also connected to the substation 103 and the failure detection device 108 via a network (not shown). You may

The alarm device 112 is a device for notifying the operator of the railway system of an alarm that a failure has occurred in the feeder circuit, and is an output device for notifying the operator of the alarm, such as a display screen or speaker. have The alarm device 112 may be a terminal device such as a mobile phone, a smart phone, or a tablet device possessed by a worker, in addition to the monitoring terminal included in the railway operation management system.

In order to ensure the reliability and availability of the failure location system, the failure location system may have a plurality of each of the failure detection device 108, the failure location device 110, and the alarm device 112. Conversely, in order to simplify the system configuration, for example, two or more of the functions of the failure detection device 108, the failure point locating device 110, and the alarm device 112 can be physically integrated into one device (computer device, server, etc.). ). For example, one computer device may be configured to implement all of the functions of the fault detection device 108, the fault location device 110, and the alarm device 112. FIG.

[1-2. Hardware configuration example]
FIG. 2 shows a hardware configuration example when the failure detection device 108 and the failure point locating device 110 are configured by a computer.
The failure detection device 108 and the failure point locating device 110 are configured by computers, and general-purpose computers such as personal computers (PCs) and server computers are used, for example.
The computer shown in FIG. 2 includes a CPU (Control Processing Unit) 1, a ROM (Read Only Memory) 2, and a RAM (Random Access Memory 3) connected to a bus 8, respectively. Furthermore, the computer includes a storage device 4 , an operation section 5 , a display section 6 and a communication interface 7 .

The CPU 1 is an arithmetic processing unit that reads out from the ROM 2 program codes of software that implement each function according to the present embodiment and executes them.
The RAM 3 is temporarily written with variables, parameters, etc. generated during the arithmetic processing. Execution of processing in each system and apparatus according to the present embodiment is realized mainly by the CPU 1 executing program codes.

For example, a keyboard, a mouse, and the like are used as the operation unit 5 , and the user uses the operation unit 5 to perform predetermined input.
The display unit 6 is, for example, a liquid crystal display monitor, and the result of the processing executed by the computer is displayed to the user by the display unit 6 . However, the computer having the operation unit 5 and the display unit 6 as shown in FIG. It may be configured without

A large-capacity data storage medium such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) is used as the storage device 4 . The storage device 4 stores a program for performing fault detection processing or a program for performing fault location processing, measured values of the ammeter 105 and the voltmeter 106, and the like.
For example, a NIC (Network Interface Card) or the like is used for the communication interface 7 . The communication interface 7 transmits and receives various data to and from the outside via a LAN (Local Area Network), a dedicated line, or the like to which terminals are connected. This communication interface 7 functions as a transmission unit to devices connected via a network. The communication interface 7 also functions as an acquisition unit that acquires current values, voltage values, and the like.

It should be noted that the computer constituting the failure detection device 108 and the failure point locating device 110 is an example, and other configurations may be used. For example, part or all of the functions performed by the fault detection device 108 and the fault location device 110 may be realized by hardware such as FPGA (Field Programmable Gate Array) and ASIC (Application Specific Integrated Circuit).

[1-3. Details of orientation processing at the time of failure occurrence]
FIG. 3 is a flow chart showing the flow of processing for detecting the occurrence of a failure by the failure detection device 108. As shown in FIG. The flowchart in FIG. 3 shows failure detection processing for detecting whether or not a failure has occurred, which is performed by the failure detection device 108 periodically or periodically.

First, failure detection device 108 measures the transmission current and transmission voltage of substation 103 from the measured values of ammeter 105 and voltmeter 106 (step S11).
Next, the fault detection device 108 determines whether or not a fault has occurred based on the measured current value (step S12).

Here, if the occurrence of a failure is detected (Yes in step S12), the failure detection device 108 opens the circuit breaker 107 installed in the feeder circuit in which the occurrence of the failure has been detected, and stops the subsequent power supply. (Step S13).
After that, the fault detection device 108 transmits the fault detection information and the current/voltage measured values to the fault location device 110 (step S14). Here, the current measurement value and the voltage measurement value to be transmitted to the failure point locating device 110 include information on the measurement time. The measurement time is determined by, for example, the failure detection device 108 having a clock function.
Note that when the fault detection device 108 detects the occurrence of a fault, the current and voltage measurements are measured at least two times at different times immediately after the fault occurs, and all of the measured current and voltage measurements are performed. Information on the value and measurement time is transmitted to the fault location device 110 .

On the other hand, if the fault detection device 108 does not detect a fault in step S12 (No in step S12), fault location information and current/voltage measurement values are used without executing the process in step S13. It is transmitted to the device 110 (step S14). If there is no failure, the transmission of the current/voltage measurement values may be omitted.

As the process of determining whether or not a failure has occurred in step S12, for example, it is determined whether or not a failure has occurred based on whether or not the acquired feeder current of the overhead wire exceeds a predetermined current value (threshold value). That is, when the feeding current exceeds a predetermined current value, processing is performed to determine that a failure has occurred. For detecting the occurrence of this failure, for example, a conventionally known high-speed circuit breaker or ΔI type failure detection device can be applied. Also, an overcurrent relay may be installed as a protection relay, and when a current exceeding a set operating value is measured, it may be determined that a failure has occurred and cut off the current.
Also, the current threshold for determining the occurrence of a fault may be statistically determined based on the operating state of the vehicle 102 existing on the overhead line 101, current measurement data when a fault current occurred in the past, or during normal operation.

Further, in step S12, in order to avoid an erroneous determination caused by an instantaneous measurement error or the like, for example, the fault detection device 108 detects that a fault current is generated when the time when the predetermined current value is exceeded is less than or equal to a predetermined time. It may be determined that it is not.
Furthermore, in step S12, even if the current value and voltage value measured at the original substation 103 are within appropriate ranges, if an abnormality is detected at another substation 103, it is determined that a failure has been detected. Then, the process proceeds to step S13. In this way, a mechanism is provided in which the failure detection devices 108 of the two substations 103 feeding in parallel operate in conjunction with each other. Try to cut off the current.

The data transmitted from the failure detection device 108 to the failure point locating device 110 may be partially or wholly encrypted in order to prevent information leakage to a third party. In addition, in order to detect spoofing by a third party and bit errors on the communication path, the data includes the ID information of the substation, and the error correction code, hash value, electronic signature, etc. for part or all of the data. You may give it.

Furthermore, when executing the transmission process of step S14, either the case of transmitting the measured value information for one time or the case of collectively transmitting the measured value information for a plurality of times may be used. For example, when measurements are performed a plurality of times in a cycle shorter than one failure determination process, the measured values obtained by the measurements performed after the previous measurement information was transmitted are transmitted all at once.
As described above, the failure detection device 108 ends the determination process for determining whether or not a failure has occurred once, and waits until the next determination process.

Next, a process of estimating a failure point by the failure point locating device 110 will be described.
First, the principle of estimating the failure point will be explained from the current change characteristics of FIG.
FIG. 4 shows an example of change in current value during normal operation and when a failure occurs. The horizontal axis of FIG. 4 indicates time (seconds), and the vertical axis indicates current (A). FIG. 4 shows a state in which a failure (ground fault) occurs at time 0 and the current increases over time.
FIG. 4 shows _two current characteristics, i.e., a current change characteristic I1 during normal operation and a current change characteristic I2 when _a failure occurs.
In the case of the current change characteristic I1 during normal feeding to the vehicle ₁₀₂ , the current value does not exceed the preset threshold value Ith. On the other hand, in the case of the current change characteristic _I2 at the occurrence of the ground fault, the current value rises sharply and exceeds the threshold value Ith.

For example, in the case of the current change characteristic I1 when the vehicle ₁₀₂ is normally powered, the current value does not exceed the threshold value Ith even if the current changes.

On the other hand, in the case of the current change characteristic _I2 at the time of occurrence of a ground fault, when the current values i21 and _i22 are measured twice, from the state of rapid increase of the current values _i21 and _i22 at the _two times, It becomes an abnormal state exceeding the threshold Ith.
Here, from the values of the current values _i21 and _i22 for the two times and conditions such as the feeding state of the substation 103, the curve of the current change characteristic _I2 at the time of occurrence of the ground fault can be calculated. It is possible to estimate the time point of By calculating the curve of the current change characteristic _I2 , the time when the ground fault occurred can be calculated, and the distance from the substation 103 to the fault point where the ground fault occurred can also be calculated.

The flow chart of FIG. 5 shows the flow of processing for locating a failure point by the failure point locating device 110 based on this principle.
The failure point locating device 110 periodically acquires measured values of the ammeter 105 and the voltmeter 106 of the substation 103 by the processing in the failure detection device 108 already described, and cooperates with the failure detection device 108. , to locate the fault point in the feeding circuit.

First, the failure point locating device 110 receives data including failure detection information and measured values from the failure detection device 108, and acquires this information (step S21). Here, the data received by the failure point locating device 110 from the failure detection device 108 is the same data as the data transmitted by the failure detection device 108 in step S14 of the flowchart of FIG.

Next, the failure point locating device 110 determines whether or not a failure has occurred based on the received data (step S22). Here, whether or not a failure has occurred is determined by, for example, confirming the failure determination result included in the failure detection information.
If it is determined in step S22 that a fault has occurred (Yes in step S22), parameters of the corresponding feeder circuit are derived (step S23). Here, the relevant feeding circuit parameters include the sending voltage, the sending current, the resistance value per unit length (wire, rail, ground), and the inductance value of the relevant substation 103 .

Then, the fault point locating device 110 derives the distance to the fault point using the derived feeder circuit parameters in an arithmetic process using an arithmetic expression prepared in advance (step S24), and calculates the distance to the derived fault point. Based on the distance, the position of the fault point is derived (step S25). A specific example of processing for deriving the distance to the fault point and the position of the fault point will be described later.
Further, the failure point locating device 110 transmits failure information to the alarm device 112 (step S26). After transmitting the failure information, the failure location device 110 saves the failure-related data in the database (step S27).

On the other hand, if no failure is detected in step S22 (No in step S22), the failure point locating device 110 does not perform the processing of steps S23 to S26, and performs the storage processing of the measured data in step S27.
When storing the failure-related data in step S27, the failure determination result, failure detection time, distance from the substation to the failure point, location of the failure point, measured values (current, voltage), measurement time, etc. preferably included.
With the flow of processing described above, the failure point locating device 110 ends the failure point locating process for locating the failure point for one time, and waits until the next failure point locating process.

If the fault detection device 108 transmits fault detection information at a predetermined time or at regular time intervals, in step S21, if the fault location device 110 cannot receive data from the fault detection device 108 even after the prescribed time has passed. , it may be determined that an abnormality has occurred. In this case, the fault location device 110 directly notifies the alarm device 112 of the abnormality.

In step S22, even if the failure detection information received from the failure detection device 108 is normal (no failure), if failure occurrence is received from the failure detection device 108 of another substation 103, the failure is detected. It may be determined that it has been detected, and the process may proceed to step S23. As a result, when a failure is detected at one substation 103, the failure point can be estimated by combining the measured values at the other substations 103, enabling rapid and highly accurate failure point location. .

Next, a specific example of processing for deriving the distance to the fault point in step S24 will be described.
Various methods are known for the calculation model of the feeding circuit. For example, it is known that the model can be modeled as a series circuit of a resistor and a coil. It is described in "Electric Railway (2nd edition), Masayuki Matsumoto, Morikita Publishing Co., Ltd., 2007, p.

Also known is a circuit configuration in which a rail is modeled as a distributed constant circuit, and the leakage conductance between the rail and the ground, the ground resistance, and the electrostatic capacitance between the rails are also included. Regarding the modeling of this rail as a distributed constant circuit, see "Thinking about track circuits that are not easily affected by return currents, etc., by Mitsuyoshi Fukuda, Railway Technical Research Institute, RRR, Vol.69, No.4, 2012. Publishing”.
Further, there is also known a feeder circuit configuration in which a train located near a substation is modeled as a current source or a power source.
In the following description, for the sake of simplicity, a failure point locating method when a feeding circuit is modeled as a series circuit of a resistor and a coil will be described. It should be noted that the present invention can be similarly applied even when a distributed constant circuit or a feeding circuit including leakage conductance, ground resistance, and capacitance is modeled.

In railway systems, the feeder circuit parameters include rail resistance per unit length, ground conductivity, rail inductance, and rail-to-rail capacitance, which can be approximated by the type of rail material, shape, gauge, and ballast. be.
Therefore, in step S23 of the flowchart of FIG. 5, when the failure point locating device 110 derives the feeder circuit parameters, these values are values generally estimated from the type of rail material, shape, gauge, track bed, etc. Alternatively, use the value obtained by preliminary measurement on site.
Also, the value measured by the voltmeter 106 or the ammeter 105 is used for the substation transmission voltage or transmission current included in the feeding circuit parameters.

The feeder circuit parameters may fluctuate due to weather, secular change, running conditions of trains, and the like. Therefore, in step S23, the feeding circuit parameters are appropriately updated based on, for example, current or voltage measurements obtained during normal train running and currents transmitted and received by track circuits installed along the tracks.

Then, in step S24, the failure point locating device 110 uses the feeder circuit parameters of the substation 103 to derive the distance to the failure point by the following processing.
If the substation 103 is modeled as a voltage source, the overhead wire and rails are modeled as resistors and coils, and each model is modeled as a feeder circuit connected in a series circuit, the current fluctuation in the feeder circuit after a fault occurs is as follows: It is calculated from Equation 1.

In Equation 1, t is the elapsed time [seconds] from the occurrence of the fault, x is the distance [km] from the substation 103 to the fault point, I(t) is the current sent from the substation at time t [A], E(t ) is the substation delivery voltage [V] at time t. In Equation 1, R is the resistance per unit distance [Ω/km], L is the inductance per unit distance [H/km], and e is the natural logarithm.

Among the parameters included in Equation 1, the voltage E(t) sent by the substation 103, the current I(t) sent by the substation 103, the resistance R per unit length, and the inductance L are derived in step S23. On the other hand, the distance x from the substation 103 to the fault point is an unknown variable. Regarding the elapsed time t from the occurrence of the failure, t=0 is set as the failure occurrence time, but since the failure occurrence time is not specified in the failure point locating device 110, the time t is also an unknown variable.

Therefore, since the two parameters (x, t) are unknown, using the current values I(t) and I(t+Δt) obtained at at least two different measurement times, by solving the simultaneous equations of Equation 1, , distance x and elapsed time t can be derived. Although the elapsed time t is an unknown variable, Δt can be derived from the difference between the measurement times of the current values. For example, Δt can be obtained from the difference between the measurement times of the two current values _i21 and _i22 shown in FIG. 4, and the failure occurrence time (time of t=0) can be derived from the elapsed time t. By determining the failure occurrence time, the distance x from the substation 103 to the failure point can also be derived.
When there is only one substation 103, the distance x from the substation 103 to the fault point is derived. Two positions of a point separated by a distance x on the other are calculated. However, as will be described later, by performing calculations based on measurement data at a plurality of substations, the failure occurrence position is determined to be any one position.

When deriving parameters, the failure-related data (including past measured values) stored in step S27 may be used.
Also, in step S24, when the current values (I(t1), I(t2), I(t3), . By applying the system identification method using As a result, it is expected that the distance to the fault point will be derived with higher accuracy.

Further, in step S24, the current value measured by the ammeter 105 of the substation 103 minus the load current for the vehicle 102 traveling within the feeding range of this substation 103 is sent as a feeding circuit parameter. You may use it as an electric current. In this case, as a method of specifying the load current of the vehicle 102, for example, a measured value of the ammeter 105 before failure detection may be used. Alternatively, the load current estimated from the train running state (notch, slope, etc.) at each time may be used. Furthermore, a wireless transmission device (not shown) for communicating with the failure point locating device 110 is provided on the vehicle 102 side, and the load current value measured by an ammeter (not shown) installed inside the vehicle 102 is It may be transmitted from the vehicle 102 to the fault location device 110 . By subtracting the load current of the vehicle 102 in this way, it is expected that the deterioration of the distance estimation accuracy caused by the operation of the vehicle 102 located near the substation 103 can be reduced.

[1-4. Example of cooperation with multiple substations]
Next, an example of deriving the position of a fault point by coordinating the detection of fault points at a plurality of substations will be described.
FIG. 6 shows the overall configuration of an embodiment of a fault location system including multiple substations and fault detection devices.
Here, as shown in FIG. 6, as failure-related data at a substation (called substation B) 203 different from the substation (called substation A) 103 for which the fault point is to be calculated, substation (B) Assume that the distance xB from 203 to the fault point is already stored. At this time, in step S24 of FIG. 5, the derived distance xA from the substation (A) 103 to the fault point and the distance xB from the substation (B) 203 to the fault point are compared to derive the position of the fault point. do.

At the substation (B) 203, an ammeter 205, a voltmeter 206, a circuit breaker 207, and a failure detection device 208 are installed. The fault detection device 208 is configured similarly to the fault detection device 108 on the substation (referred to as substation A) 103 side, and transmits fault occurrence information and measured values to the fault location device 110 via the network 111 .
Here, as shown in FIG. 6, when there is a failure point (ground fault point) in the feeding circuit between the substation (A) 103 and the substation (B) 203, the distance calculated at each is It is possible to match and specify the position.

FIG. 7 shows a specific example of identifying a fault point between substation (A) 103 and substation (B) 203 .
Here, the substation (A) 103 exists at the 5 km point, the substation B exists at the 15 km point, the distance to the fault point derived from the measurement data of the substation (A) 103 is 3 km, and the distance to the fault point of the substation (B) 203 is 3 km. A case where the distance to the fault point derived from the measurement data is 7 km is shown.

If the distance to the fault point derived from the measurement data of the substation (A) 103 is 3 km, the fault point may be a 2 km point or an 8 km point. On the other hand, if the distance to the fault point derived from the measurement data of the substation (B) 203 is 7 km, the fault point may be 8 km or 22 km.
Here, the failure point locating device 110 compares the distances derived from the two substations 103 and 203, and derives the location of the failure point as the 8 km point from the matching location.

The example in FIG. 7 is a case where an ideal position can be derived. For example, it is assumed that a single point cannot be specified. In that case, based on the distance derived by the failure point locating device, it is conceivable to derive a certain range in which the failure point may exist instead of specifying one point.
Specific examples of this case are shown in FIGS. 8 and 9. FIG.

FIG. 8 shows an example in which the distance ranges from the substations 103 and 203 overlap, and the failure point locating device 110 cannot narrow down the failure point to one point. For example, from the measurement data at the substation (A) 103 side, a point 4 km from the substation (A) 103 is derived as the failure point, and from the measurement data at the substation (B) 203 side, Assume that the 8 km point is derived as the failure point.
At this time, the entire range from the 7 km point to the 9 km point where the ranges overlap is derived as a range in which the fault point may exist (hereinafter referred to as "location candidate range"). Alternatively, the midpoint of the orientation candidate range (here, the 8 km point) is derived as the failure point.

FIG. 9 shows an example in which the distance ranges from the substations 103 and 203 do not overlap, and the failure point locating device 110 cannot narrow down the failure point to one point. For example, from the measurement data at the substation (A) 103 side, a point 2 km from the substation (A) 103 is derived as the failure point, and from the measurement data at the substation (B) 203 side, Assume that the point of 6 km is derived as the failure point.
At this time, the range between the range of distance derived by one substation (A) 103 and the range of distance derived by the other substation (B) 203 (range from point 7 km to point 9 km) is located. Candidate range. Alternatively, the midpoint of the orientation candidate range (here, the 8 km point) is derived as the failure point.

Also, the weighting of the distance obtained at each substation may be adjusted for the location candidate range derived by these processes. That is, by adjusting the feeder circuit parameters using a technique such as system identification, the point with the highest probability of becoming a failure point may be derived from the location candidate range. Furthermore, the distribution of the probability that a failure point exists at each point within the orientation candidate range may be derived. If the location candidate range is larger than a certain value, it is determined that noise, parameter errors, multiple failures, etc., that make failure point location difficult, have occurred. information may be output.

Information about the failure point and the candidate orientation range derived by these processes is transmitted to the alarm device 112 . At this time, the failure point locating device 110 sends to the alarm device 112 the measured values (current, voltage), information on the section of the overhead wire where the fault current is detected, and information on the detection time, in addition to the information on the failure point or the location candidate range. preferably sent. As a result, it becomes possible to appropriately perform maintenance and inspection support by estimating the scale of failure damage and the like.
Although the examples of FIGS. 7 to 9 show examples of calculating the fault point from the distances derived by two substations, it is possible to calculate the fault point from the distances derived by three or more substations. is also possible.
As described above, the fault locating apparatus 110 of the present embodiment can perform fault locating with high accuracy without synchronizing the measurement times of a plurality of substations.

[1-5. Example of short-circuit accident]
In the embodiments described so far, the case where a ground fault occurs as a failure event at the failure point 109 (FIGS. 1 and 6) has been described.
On the other hand, as shown in FIG. 10, for example, even if a short circuit occurs at the fault point 109' where the overhead wire 101 and the rail 104 come into contact with each other, the fault locating device 110 The fault point can be located by the same processing as .

In this way, the flow amount and path of the fault current are determined according to the surrounding environment such as rail resistance, leakage conductance, earth resistance, and ground resistance between the rail and the earth. Here, it is generally assumed that when a short-circuit fault occurs, the rate of fault current flowing to the substation via the rail as the return line increases, while when a ground fault occurs, the proportion of the fault current that flows via the ground as the return line increases. Therefore, the rail inductance and rail resistance dominate the fluctuation of the fault current flowing through the rail, and the ground return inductance and ground resistance dominate the fault current flowing in the ground.

Further, in step S23, when the feeder circuit parameters are derived, if a failure event can be estimated, by changing the applied resistance and inductance according to the failure event, the failure point location accuracy can be improved. . As a method for estimating fault events, for example, short-circuit faults tend to generate a large fault current, so if the measured fault current exceeds a certain value, it is assumed to be a short-circuit fault, and if it is below a certain value, it is assumed to be a ground fault. , to derive the feeder circuit parameters corresponding to each fault.

<2. Second Embodiment>
Next, a second embodiment of the invention will be described in detail with reference to FIGS. 11 to 13. FIG.
[2-1. Configuration of fault location system]
FIG. 11 shows the overall configuration of a fault location system in this embodiment.
In the first embodiment described above, the fault point is located from the measured values of the ammeter 105 and the voltmeter 106 installed at the substation 103 . On the other hand, in this embodiment, as shown in FIG. , 113, the feeder circuit parameters are derived to locate the fault point.
Here, the rail potential is the voltage (potential difference) between the rail and the ground (installation mat, auxiliary return line, equipment ground network, etc.).
The fault locating system shown in FIG. 11 has the same configuration as the fault locating system shown in FIG. 1 except that the voltmeter 113 for measuring the rail potential is provided and the ammeter 105 is omitted.

It is known that when a ground fault occurs, the rail potential near the fault point rises in proportion to the magnitude of the fault current. A DC high-voltage grounding relay is known as an electrical protection system that utilizes this phenomenon.

[2-2. Flow of fault location process]
Next, referring to the flowcharts of FIGS. 12 and 13, the process of periodically or periodically locating failure points using the rail potential by the failure detection device 108 and the failure point locating device 110 will be described.

FIG. 12 is a flow chart showing the flow of failure detection processing for detecting whether or not a failure has occurred, which is performed by the failure detection device 108 periodically or periodically.

First, the failure detection device 108 measures the transmission voltage of the substation 103 from the measured value of the voltmeter 106, and measures the rail potential from the measured value of the voltmeter 113 (step S31).
Next, the fault detection device 108 determines whether or not a fault has occurred based on the measured rail potential (step S32).

Here, if the occurrence of a failure is detected (Yes in step S32), the failure detection device 108 opens the circuit breaker 107 installed in the feeder circuit in which the occurrence of the failure has been detected, and stops the subsequent power supply ( step S33).
After that, the failure detection device 108 transmits the failure detection information, the overhead wire voltage measurement value, and the rail potential measurement value to the failure point locating device 110 (step S34). Here, the measurement value to be transmitted to the failure point locating device 110 includes information on the measurement time.

On the other hand, if the fault detection device 108 does not detect a fault in step S32 (No in step S32), the fault-free information, the overhead line voltage measurement value, and the rail potential measurement value are obtained without executing the processing in step S33. is sent to the failure point locating device 110 (step S34). If there is no failure, the transmission of the voltage measurement value and the rail potential measurement value may be omitted.

FIG. 13 is a flow chart showing the flow of processing for locating failure points by the failure point locating device 110 .
The failure point locating device 110 periodically acquires the measured value (tension line voltage) of the voltmeter 106 and the measured value (rail potential) of the voltmeter 113 of the substation 103 by the processing in the failure detection device 108 already described. , and cooperates with the fault detection device 108 to locate fault points in the feeder circuit.

First, the fault locating device 110 receives data including fault detection information and measured values from the fault detection device 108 (step S41). Here, the data received by the failure point locating device 110 from the failure detection device 108 is the same data as the data transmitted by the failure detection device 108 in step S34 of the flowchart of FIG.

Next, the failure point locating device 110 determines whether or not a failure has occurred based on the received data (step S42). Here, whether or not a failure has occurred is determined by, for example, confirming the failure determination result included in the failure detection information.
If it is determined in step S42 that a fault has occurred (Yes in step S42), parameters of the corresponding feeding circuit are derived (step S43). The relevant feeding circuit parameters include the transmission voltage of the relevant substation 103, the rail potential, the resistance value per unit length (wire, rail, ground), and the inductance value.

Then, the fault point locating device 110 uses the derived feeder circuit parameters to derive the distance to the fault point (step S44), and calculates the distance to the derived fault point by arithmetic processing using an arithmetic expression prepared in advance. Based on the distance, the position of the fault point is derived (step S45).
Furthermore, the failure point locating device 110 transmits failure information to the alarm device 112 (step S46). Also, after transmitting the failure information, the failure location device 110 saves the failure-related data in the database (step S47).

On the other hand, if no failure is detected in step S42 (No in step S42), the failure point locating device 110 does not perform the processing of steps S43 to S46, and performs the storage processing of the measured data in step S47.
In step S47, when storing the failure-related data, the failure judgment result, failure detection time, distance from the substation to the failure point, location of the failure point, measured values (overhead line voltage, rail potential), measurement time, etc. preferably included.
With the flow of processing described above, the failure point locating device 110 ends the failure point locating process for locating the failure point for one time, and waits until the next failure point locating process.

When deriving the distance to the fault point in step S44, it differs from the first embodiment in that fault detection and fault point evaluation are performed based on the rail potential in the vicinity of the substation.
Here, in step S43, when deriving the feeder circuit parameters, based on Ohm's law, the above-described fault current calculation formula (Equation 1), the leakage conductance between the rail and the ground, the ground resistance, Parameters such as resistance from the substation to the rail potential measurement point are used. The resistance between the fault point and the rail potential measurement point is derived from the overhead wire resistance, rail resistance, ground resistance, ground resistance between the rail and the ground, etc. that make up the feeder circuit. For example, by specifying the distance x from the substation 103 to the fault point and modeling structures (rails, trackbeds, viaducts, etc.) near the rails with electric circuits, the above-described resistance values can be calculated.

In step S44, by the same procedure as in step S24 of the first embodiment, the substation 103 to derive the distance to the fault point.
At that time, as in the method shown in the first embodiment, distance x and elapsed time t are assumed to be unknown variables, and simultaneous equations are calculated using rail potential measurement values obtained at least at two different measurement times. By solving, the distance x and elapsed time t can be derived.

Thus, according to the second embodiment as well, the fault locating device 110 and the fault detecting device can detect the fault point with higher accuracy than the measured value of the rail potential without using the current sent from the substation. Orientation can be performed.

<3. Variation>
The present invention is not limited to each embodiment described above, and includes various modifications.
For example, in each of the above-described embodiments, the failure point locating system obtains the feeding current, determines the presence or absence of a failure, and locates the failure point. On the other hand, when a failure is detected, the failure point locating system may notify another external system of the occurrence of the failure and cause control to take into account the detected failure.

For example, the failure point locating system is configured to be connected via a network to a railway operation management system, a railway safety system, or a substation system that manages substations. Then, the failure point locating system notifies the operation control system and railway safety system that a fault current has occurred and information on the location where an abnormality is presumed to occur, thereby restricting train entry to the location. You may let
In addition, the failure detection device may notify the substation system that manages the substation of the occurrence of an abnormality (and information on the substation where the failure is thought to occur), and limit power supply to the substation.

In addition, although the example of comparing the calculated distances when the fault point locating device locates the fault point from the information calculated at a plurality of substations has been shown, when calculating the distance at each substation, , t=0 may be matched to improve the accuracy. That is, if the calculation using the parameters measured at each substation does not match the time t=0 at which the ground fault occurred, etc., the time t=0 is set to an intermediate value, etc. You may improve the precision of an arithmetic operation.

Further, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to those having all the described configurations. In addition, in the configuration diagrams and functional block diagrams such as FIG. 1, only those control lines and information lines that are considered necessary for explanation are shown, and not all control lines and information lines are necessarily shown on the product. do not have. In practice, it may be considered that almost all configurations are interconnected. In addition, in the flowcharts shown in FIGS. 3 and 5, etc., the execution order of some processing steps may be changed or some processing steps may be executed at the same time as long as the processing results of the embodiment are not affected. You may do so.

DESCRIPTION OF SYMBOLS 1... Central control unit (CPU), 2... ROM, 3... RAM, 4... Storage device, 5... Operation part, 6... Display part, 7... Communication interface, 8... Bus line, 101... Overhead line, 102... Vehicle 103 Substation 104 Rail 105 Ammeter 106 Voltmeter 107 Breaker 108 Fault detector 109, 109' Fault point 110 Fault point locator 111 Network 112 Alarm device 113 Voltmeter 203 Substation 205 Ammeter 206 Voltmeter 207 Circuit breaker 208 Failure detection device

Claims (8)

A failure point locating device for estimating a failure point, which is a position where a failure occurs in an overhead wire of a DC electric railway,
an acquisition unit that acquires the transmission voltage of the substation and the feeder current or rail potential of the overhead line;
Based on a formula for estimating the time variation of the fault current at the time of fault occurrence, the measured values of the feeding current or the rail potential obtained at at least two different measurement times are used to determine the distance from the substation to the fault point. an arithmetic processing unit that derives the distance;
a transmitting unit that transmits information on the position of the fault point derived by the arithmetic processing unit;
The arithmetic processing unit collates estimated distances from the substation to the fault point derived from at least two different substations, and derives a position where the estimated distances match as the fault point.
Fault locator. The current obtained on the train, the current of the overhead wire obtained before the failure is detected, or the load current estimated from the running state of the train at each time is used as the load current of the train running within the feeding range of the substation. year,
The fault location according to claim 1, wherein the arithmetic processing unit uses a value obtained by subtracting the load current of the train from the feeding current of the overhead line acquired at the substation as the measured value of the feeding current. Device. When collating the estimated distance from the substation to the fault point derived from at least two different substations, the arithmetic processing unit, when the distance ranges from the respective substations to the fault point overlap, , the overlapping range is derived as an orientation candidate range as a range in which a fault point may exist,
If the distance ranges from each substation to the fault point do not overlap, the range sandwiched between the distance range derived by one substation and the distance range derived by the other substation is defined as the fault point. 2. The failure point locating apparatus according to claim 1 , wherein the location candidate range is derived as a range in which a can exist. When the arithmetic processing unit compares estimated distances from the substation to the fault point derived at least two different substations to derive the location candidate range,
deriving a point having the highest probability of becoming the failure point from the location candidate range, or deriving a distribution of the probability that the failure point exists at each point in the location candidate range, or deriving the location candidate range 4. The failure point locating device according to claim 3 , wherein an error is determined when the difference is larger than a certain value. The arithmetic processing unit determines a fault event type such as a ground fault or a short circuit fault based on the measured value of the feeding current obtained at the substation,
2. The fault locating apparatus according to claim 1, wherein, based on the discriminated fault event type, a feeder circuit parameter used in the calculation formula for estimating the time variation of the fault current when a fault occurs is changed. Information about the failure event detected in at least one of a railway operation control system, a railway safety system, and a substation system connected via a network when it is determined that a failure has occurred in the overhead line. The failure point locating device according to any one of claims 1 to 5 , which transmits the A failure point locating system comprising a failure point locating device for estimating a failure point, which is a position where a failure has occurred in an overhead wire of a DC electric railway, and an alarm device for notifying the failure point,
The failure point locating device,
an acquisition unit that acquires the transmission voltage of the substation and the feeder current or rail potential of the overhead line;
Based on a formula for estimating the time variation of the fault current at the time of fault occurrence, the measured values of the feeding current or the rail potential obtained at at least two different measurement times are used to determine the distance from the substation to the fault point. an arithmetic processing unit that derives the distance;
a transmission unit that transmits information on the position of the fault point derived by the arithmetic processing unit;
with
The alarm device includes a notification unit that notifies a failure point when receiving information transmitted by the transmission unit ,
The arithmetic processing unit of the fault point locating device compares the estimated distances from the substation to the fault point, which are derived from at least two different substations, and derives a position where the estimated distances match as the fault point. do
Fault location system. A fault location method for estimating a fault point, which is a position where a fault occurs in an overhead wire of a DC electric railway,
Acquisition processing for acquiring the transmission voltage of the substation and the feeding current or rail potential of the overhead line;
Based on a formula for estimating the time variation of the fault current at the time of fault occurrence, the measured values of the feeding current or the rail potential obtained at at least two different measurement times are used to determine the distance from the substation to the fault point. Arithmetic processing for deriving a distance;
a notification process for transmitting information on the position of the fault point derived by the arithmetic process ,
In the arithmetic processing, estimated distances from the substation to the fault point derived from at least two different substations are collated, and a position where the estimated distances match is derived as the fault point.
fault location method.

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