JP2585345B2 - Polarity determination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is intended to easily and reliably locate an accident occurrence position such as a ground fault occurring in a power supply line such as a transmission line or an underground line. The present invention relates to an improvement of a possible polarity determination method and an accident point location method.

2. Description of the Related Art Even though a power supply line such as a transmission line or an underground line has a sufficient withstand voltage configuration, when a ground fault occurs or the like, insulation is destroyed and a large current flows. For this reason, it is necessary to quickly detect the location of the accident and prepare for the accident. For this reason, an accident point detecting device as shown in FIG. 5 has been conventionally used. Hereinafter, the configuration and operation of the conventional accident point location device will be described with reference to FIG.

In FIG. 5, the conventional accident point locating device is a transmission line 1
Provided at each of the predetermined points A and B of the transmission line 1
The current detectors 2a and 2b, which are current transformers, for example, detect the current flowing through the current source, and count the clock signal from the clock source 4 and respond to the respective surge detection signals from the current detectors 2a and 2b. Counters 3a and 3b for providing the count value of the above to the calculation circuit 5, a calculation circuit 5 for receiving the count values from the counters 3a and 3b and performing a predetermined operation to locate the fault point, and a calculation result of the calculation circuit 5 And a display unit 6 that displays Counters 3a and 3b are clock sources 4
The synchronous operation is performed by the clock signal from. Next, the operation will be described.

For example, if a ground fault occurs at the point P of the transmission line 1,
Surge current flows toward points A and B. When current detectors 2a and 2b provided at points A and B detect a surge current of a certain level or more, they supply a surge current detection signal to counters 3a and 3b, respectively. In response to the surge current detection signal, the counters 3a and 3b supply the count value at that time to the calculation circuit 5 (at this time, the counters 3a and 3b continue the counting operation). The calculation circuit 5 performs the following calculation based on the given count value. Assume that the arrival times of the surge currents at the points A and B are T1 and T2, respectively, and the surge propagation speed of the transmission line 1 is V. Here, T1 + T2 = X is calculated in advance and stored in the calculation circuit 5. This value X is the surge propagation speed V
And the distance L between the points A and B. In such a case, the surge arrival time at the point A is given by the following equation.

T1 = [(T1 + T2) + (T1 + T2)] / 2 = (X + Y) / 2 Therefore, 1 = V · T1, where Y = T1−T2, l is the distance from the point A to the accident point P.

Therefore, by multiplying each count value by the period of the clock signal of the clock source 4, the times T1 and T2 are obtained, and the distance l from the point A to the accident point P is obtained by the above equation. This distance 1 is displayed on the display unit 6.

[Problem to be Solved by the Invention] Since the conventional fault point locating device as described above makes a determination using only a surge generated at the time of occurrence of an accident, when impulse noise or the like is given from the outside, the impulse noise is reduced. There is a problem that malfunction is often caused because the current is detected as a surge current.

In order to eliminate the problems of the fault locating device using only the surge current as a trigger signal as described above, a locating device as shown in FIG. 6 has been devised. This sixth
The accident point locating device shown in the figure is disclosed in Japanese Patent Application No. 137136, which was invented by the present inventors and assigned to the present applicant. The principle configuration and operation of the polarity determination type accident point locating apparatus shown in FIG. 6 will be described below. In the configuration shown in FIG. 6, predetermined points A, B
By monitoring the transmission line current, the fault occurrence section and the fault point are located.

At point A, a magnetic field sensor 10 that detects a current flowing through the transmission line 1 by detecting a magnetic field induced by the transmission line current.
a, a counter 11a operating in synchronization with a clock signal CLK from a clock source (not shown) and counting the clock signal CLK, and a counter 11a in response to a surge detection signal from the magnetic field sensor 10a. Hold, polarity judgment circuit 1
In response to the fault current detection signal from 3a, the count value of the held count value is made valid and transmitted to the transmitter 14a, and the polarity of the fault current flowing through the transmission line 1 is determined by the fault current detection signal from the magnetic field sensor 10a. A polarity determining circuit 13a for determination and a transmitter 14a for multiplexing and transmitting information from the polarity determining circuit 13a and the count holder 12a are provided.

At point B, similarly to point A, a magnetic field sensor 10b,
A counter 1 that operates in synchronization with the clock signal CLK transmitted from the counter 11a and counts the number of clock signals CLK.
1b, the count value of the counter 11b is held in response to the surge detection signal from the magnetic field sensor 10b, and the count value held in response to the fault current detection signal from the polarity determination circuit 13b is sent to the transmitter 14b as valid data. Count holder 1 for transmission
2b, a polarity determining circuit 13b that determines the polarity of the fault current based on the fault current detection signal from the magnetic field sensor 10b and provides the same to the transmitter 14b, and transmission that multiplexes and transmits information from the count holder 12b and the polarity determining circuit 13b. Vessel 14b is provided.

As a device for locating accident points and accident sections,
A location device 15 that performs a predetermined operation in response to information from the transmitters 14a and 14b to perform location of an accident section and an accident point;
A display device 16 for displaying the orientation result of the orientation device 15 is provided. FIG. 7 is a waveform diagram showing a behavior of a fault current flowing through a transmission line when a fault occurs. As shown in FIG. 7, a large surge current flows from the fault point to each point A and B at the initial time ta of the fault occurrence, and is followed by a stable fault current (frequency 50/60 Hz). Flows. Since the fault current exceeds the predetermined positive and negative reference values R1 and R2 every cycle T (T is 1/2 of the fault current cycle), the fault current exceeds the reference values R1 and R2 for each cycle T. Is detected, and the current polarity, for example, the 1.5th wave of the current exceeding the reference values R1 and R2 is detected as the fault current polarity. At this time, transient harmonics flow from the occurrence of the fault until a stable fault current flows.
Since the frequency does not exceed 1, R2, the transient harmonics are not erroneously determined as the fault current, and the fault current polarity is accurately determined. The detection of the surge current is performed based on whether or not a predetermined reference value R3, R3 'is exceeded. Here, preferably, R3, R3 '> R1, R2 are set.

In the section determination, if the polarities of the fault currents at the points A and B are the same, the fault occurrence point is determined to be outside the section, and if the fault currents have different polarities, it is determined to be within the section.

Here, the counters 11a and 11b operate synchronously with the clock signal CLK, but when the distance between the points A and B is long, the counter 11b at the point B counts the counter 11a at the point A for the clock signal propagation time. Is delayed from the count operation. However, since the counters 11a and 11b perform the synchronous operation using the same clock signal, the delay is always constant, and the delay of the counting operation is corrected by measuring the delay. .

FIG. 8 is a diagram showing a method of correcting a delay in the counting operation of points A and B. A method of measuring the count delay will be briefly described with reference to FIG.

A pulse is generated simultaneously with the start of the counting operation of the counter 11a at the point A and transmitted from the point A to the point B.
At the point B, the pulse transmitted from the point A is returned to the point A as it is. The counter 11a at the point A stops the counting operation in response to the returned pulse. At this time, half of the count value indicated by the counter 11a is the counter 11a at the point A.
4 shows a delay in the counting operation of the counter 11b at the point B with respect to the time point. This data can be used as count correction data. Next, with reference to FIGS. 6 to 8, the principle operation of the polarity determination type accident point locating apparatus to which the present invention is applied will be described.

First, when a ground fault occurs in the transmission line 1, for example,
The current flows as shown in the figure.
Reach A, B. Each of the magnetic field sensors 10a and 10b is a transmission line 1
Detection signals corresponding to the current flowing through the
b and the polarity determination circuits 13a and 13b. The count holders 12a and 12b respond to the surge detection signals from the magnetic field sensors 10a and 10b to capture and hold the counts of the counters 11a and 11b (the counters 11a and 11b continue counting operations). On the other hand, the polarity determination circuits 13a and 13b are magnetic field sensors 10a and 10b.
The polarity of the fault current is determined based on the above-described principle in response to the current detection signal from the controller. The count holders 12a and 12b respond to the fault current detection signals (signals indicating that the polarity has been determined) from the polarity determination circuits 13a and 13b and provide the held data as valid data to the transmitters 14a and 14b. . At this time, fault current polarity information of the polarity determination circuits 13a and 13b is also supplied to the transmitters 14a and 14b. The transmitters 14a and 14b multiplex the given determination polarity and count value and
Give to. The locating device 15 locates an accident point and an accident section based on the given information and the frequency of the clock signal. Now, an example of the orientation operation will be specifically described. The count frequency (clock signal frequency) f of the counters 11a and 11b is 30 MHz (corresponding to 10 m per pulse), the counter display is 4 digits (0000 to 9999), and the delay of the count operation accompanying clock propagation is 10 pulses. . The distance between points A and B is 10 km.

Now, the count values of the counters 11a and 11b at the reference time t0 are set to 0000 and 9990, respectively, and the counts taken into the count holders 12a and 12b when the surge reaches 0350 and 0640, respectively.
And At this time, the distance X from the midpoint between the points A and B to the accident point is given by the following equation.

X = [350− (640 + 10)] / 2 = −150 Since one pulse corresponds to 10 m, −150 × 10 =
-1.5Km indicates the distance between the accident point and the center point of section AB. The sign of the given numerical value has directionality from the center point, and the direction of the point A from the center point of the sections A and B is negative, and the direction of the point B is positive. Therefore, the accident point is determined to be a point 1.5 km away from the center point of sections A and B on point A side.

By performing the above-described calculation, the location of the accident located by the orientation device 15 is provided to the display device 16 together with the determination polarity from the polarity determination circuits 13a and 13b. Is displayed on the display device 16. Here, when an accident occurs outside the section between the points A and B, the accident point is, for example, a point A or a point B, that is, a distance to the accident point is 5 km (a distance between the points A and B is 10 km).
And the polarity determination circuits 13a and 13b
It is displayed together with the display inside or outside the section from, so that it is possible to know on which side of the section of points A and B the accident has occurred.

Here, in the above configuration, the polarity determination circuit
13a and 13b both describe the case where the fault current is detected and its polarity is determined. However, depending on the connection path between the points A and B, the fault current may flow to only one of the points. For example, point A is connected to a power source,
When the fault current occurs in the sections A and B, the fault current flows to the point A but does not flow to the point B. Therefore, in this case, it is conceivable that the count holder at the point B determines that the received count value is invalid and does not give it to the transmitter 14b.
In this case, the fault current detection signal from the polarity determination circuit 13a is transmitted to the count holder 12b at the point B, and the count value held by the count holder 12b is used as valid data, so that the fault point is detected. It is configured so that orientation can be performed reliably. At this time, for example, if no fault current is detected at the point B, the transmitter 14b sends the count value and the polarity determination failure result to the orientation device 15. FIG. 9 shows an example of a configuration in the case where an accident point locating system is configured along a transmission line with the locating device having the above-described configuration. In FIG. 9, the direction of the thick arrow indicates the direction in which the surge current detected based on the data of the terminal device LS provided at each point flows, and the hatched portion indicates the accident occurrence section. .

In the case of the above-described configuration, the fault section and fault location are determined by the polarity information of the fault current, the propagation direction of the surge (this can be determined by the sign of the distance display), and the fault location in each section. By taking this into account, the determination point provided at the central monitoring station MS locates the accident point. However, due to some malfunction,
When an accident determination result as shown in the figure is obtained, the accident point occurs between sections F and G, and between sections B and C and between sections J and It is determined that the surge propagation directions of the slave stations LS10 and LS9 provided between K are incorrect. Therefore, in this case, the above-mentioned criterion information, that is, the polarity information of the fault current, the propagation direction of the surge current and the information in which a certain weight is applied to the position of the fault point in each section are transmitted, and the fault point is stochastically located. By doing so, the accuracy of the accident section location can be improved. At this time, the value of the weight assigned to each criterion is determined based on experimental data, and if the location probability of the section where the accident actually occurs increases, Since the rating probability becomes smaller, the location of the accident point is to be located by comparing the location probability with the threshold probability.

In the accident point locating device having the above configuration, the sixth
As described with reference to the figure, the same clock signal CLK
Is used to synchronize the counting operation.
That is, for example, in the case of the configuration shown in FIG.
The clock signal CLK is provided from the central monitoring station (master station) MS to each of the terminal devices LS1 to LS10. Therefore, when a failure occurs in one terminal device LS, the clock signal is transmitted to a lower terminal device (here, a lower device indicates a device provided farther than a central monitoring station along a transmission line). The clock signal is not transmitted, and each terminal device cannot perform the detection operation. On the other hand, in the upper device, information for correcting the counting operation is not given from the lower device, so that an accurate counting operation cannot be performed, and an accurate accident point location is calculated. A problem arises in that it is no longer possible. Therefore, in the polarity determination method fault point locating device as described above, if one terminal device falls into a failure state and transmission and return of the clock signal become impossible,
Problems such as the inability of the entire orientation device system to operate and the inability to perform an accurate orientation operation occur.

Therefore, an object of the present invention is to eliminate the above-described problems of the polarity determination type accident point locating device, and to prevent the operation of the entire locating device system from being stopped even when a failure occurs in a terminal device or the like. An object of the present invention is to provide a polarity determination type accident section locating apparatus.

[Means for Solving the Problems] In order to achieve the above-mentioned object, in the polarity determination type accident point locating device according to the present invention, each terminal device is provided with a clock generator, and a clock signal from the clock generator is provided. It is possible to prevent the failure of one terminal device from affecting the system down.

That is, in the first invention, two terminal devices are configured as a unit, and a clock signal from a clock generator in one terminal device is given as a clock signal for counting operation of the other terminal device, and one The clock signal supplied from the generator is used only in two terminal devices.

In the second invention, each clock generator is provided, and clock detecting means for detecting whether or not a clock signal given from a terminal on the upper side or a central device is provided. When a clock signal from a neighboring device on the side is not detected, a clock signal from a clock signal generator provided uniquely for each device is sent to a lower-level device.

[Operation] In the first invention, the loop through which the clock signal is transmitted is closed between two terminal devices as constituent units or between a central monitoring station and a terminal device adjacent thereto. Even if a device fails and cannot send a clock signal to a lower terminal device, a clock signal is sent from an adjacent terminal device to a lower terminal device, causing an accident between lower terminal devices. The point location operation becomes possible, and even in the higher-level device, the clock signal is normally given to all the higher-level devices than the faulty device, the device operates normally, and the fault location operation can be performed.
It is possible to prevent a down state of the entire system due to a failure of one terminal device.

In the second invention, when the clock signal is not supplied from the higher-level device, the clock signal from the clock generator provided in the terminal device is supplied to the lower-level terminal device as a synchronization signal. Therefore, a clock signal is given to each lower-level terminal device, and an operation for locating an accident point when an accident occurs can be performed. Similarly, since the clock signal is transmitted from the higher-level device to the higher-level device than the failed device, each device can perform the location operation similarly. As a result, in the above-described polarity determination type accident point locating device, it is possible to prevent the entire system from being down due to the failure of one device, and it is possible to make only the minimum necessary fault section. In the event that a failure occurs in a device such as a terminal, a backup system can be prepared.

[Embodiment of the Invention] Fig. 1 is a view showing the concept of a polarity determination type accident point locating apparatus according to an embodiment of the present invention. In FIG. 1, terminal devices LS1, LS2 and LS3 are representatively illustrated. Each of the terminal devices LS1 to LS3 has its own clock signal generator C1, C
2 and C3. Clock generator for terminal device LS1
The clock signal from C1 is provided as a clock signal for the lower terminal device LS2. The clock signal of the clock generator C2 of the terminal device LS2 is supplied to the adjacent lower terminal device LS3 as a clock signal. Each of the terminal devices LS1 to LS3 is configured to transmit each count operation and count error information to the higher-order device using a clock signal given from a higher-order adjacent device as a synchronization signal. Therefore, two terminal devices (for example, LS1, LS
Between 2), the clock signal transmission path loop is closed.

FIG. 2 is a block diagram showing an example of a specific configuration of the terminal device shown in FIG. 1 in more detail. FIG. 2 shows the configuration of one terminal device. In FIG. 2, a terminal device LS includes an O / E converter 101 that receives a clock signal from an adjacent upper terminal device or a central monitoring station (master station) via an optical fiber and converts the clock signal into an electric signal. ,
A counter A103 that operates in synchronization with a clock signal from the O / E converter 101 and counts the number of clock signals, and starts a counting operation in response to a start pulse generated at predetermined time intervals from the counter A103, A counter B104 for stopping a count operation in response to a stop signal from the O / E converter 105, and an electric converter for receiving a power supply line current detection signal from a magnetic field sensor, converting the signal to an electric-optical signal, and performing optical-electrical conversion. An optical-electrical converter 107; a data acquisition unit 108 for acquiring the count number from the counter A103 in response to a surge detection signal from the electric-optical-electrical converter 107; A polarity judging circuit 109 for judging the polarity of the fault current in response to the fault current detection signal, and a count value captured by the data capturing unit 108 in response to the fault current detection signal from the polarity determining circuit 109 are held. data Holding unit 110,
A data multiplexing transmission unit 111 for multiplexing and transmitting the count value held by the data holding unit 110 and the polarity determination data from the polarity determination circuit 109, and electro-optically transmitting the multiplexed data from the data multiplexing transmission unit 111. And a conversion unit 112 for converting and outputting. The start pulse from the counter A103 is provided as a start pulse to the counter B104 of the terminal device LS and is also used as a stop pulse to the counter B included in the adjacent higher-level device. The counter B104 starts a counting operation by a start pulse generated every predetermined time from the counter A103, and stops the counting operation by a start pulse from the counter A included in the lower terminal device. Therefore, the counter B1
The count value of 04 generates data for correcting the delay of the counting operation due to the clock signal propagation delay with the lower terminal device. Optical-to-electrical converters and electrical-to-optical converters are used because optical fibers are used to connect the various parts, to eliminate the effects of noise in each signal and to increase the speed of signal transmission. It is for utilizing. The data multiplex transmission unit 111 multiplexes the count value held by the counter B104 and transmits the multiplexed value. Data multiplex transmission section
Reference numeral 111 multiplexes information in the terminal device LS together with data transmitted from the lower terminal device, and transmits the multiplexed information to the data multiplex transmission unit included in the higher terminal device. Therefore, the data sent from each terminal device is given to a central monitoring station (master station).
The fault point is located based on information from each terminal device.

Further, in the configuration shown in FIG. 2, a clock source is
100 is provided, and a clock signal from the clock source 100 is transmitted as a synchronization clock signal to the lower terminal device via the electro-optical converter 102.

In the above-described configuration, when an fault current is detected in any one of the terminal devices, the data is transmitted to the data multiplex transmission unit provided in each terminal device, so that the fault current is not detected in the device. In this case, it is detected that an accident has occurred, and the count value held by the data holding unit and the data from the polarity determination circuit (in the case where no fault current is detected, data in which polarity cannot be determined in that case) are multiplexed and transmitted. Is done. With such a configuration, even if no fault current is detected due to the connection configuration, if a fault current occurs in any one of the terminal devices, the surge that first triggered the acquisition of the count number may cause a fault. Since it is determined that the accident is accompanied, it is possible to more reliably locate the accident section and the point.

Here, in any of the terminal devices, when no fault current is detected, the surge triggered is determined to be a noise pulse, and each count value is reset based on information from a processing unit provided at a central monitoring station. Is done.

With the above-described configuration, the clock signal transmitted from the central monitoring station is used as a synchronization clock signal only in the terminal device adjacent thereto, and two terminal devices are similarly configured in the lower terminal device. Only in a loop as a unit, a clock signal from a higher-level device is used as a clock synchronization signal. Therefore, even if one terminal device breaks down and cannot send a clock signal to the next stage (lower terminal device), the terminal device in a normal state will be lower than the lower terminal device. Since the clock signal can be transmitted to the locating device system, the down state of the entire positioning device system is not caused by the failure of one terminal device.

That is, in the configuration of FIG.
If LS2 fails, the terminal devices LS1 and LS3 cannot perform the counting operation or the detecting operation.
Since a terminal device lower than LS3 and a terminal device higher than terminal device LS1 can perform a normal determination and detection operation, in the orientation device system, the section in which the determination is impossible is performed between the terminal devices LS1 and LS2. And only between the terminal devices LS2-LS3. Such a failure state is monitored by detecting data transmitted from each data transmission unit at a central monitoring station, and a failure section can be specified.

FIG. 3 is a diagram showing a principle configuration of a polarity determination type accident point locating device according to the second invention, and shows a case where a clock signal switching unit is provided in each terminal device. That is, each of the terminal devices LS1 to LS3 is provided with the clock signal generators C11 to C13, and selects either the clock signal from the clock signal generator in each terminal device or the clock signal from the upper terminal device. Switches (clock selection circuits) S1 to S3 for transmitting the signals to the lower terminal device are provided. With such a configuration, even when one terminal device fails, the clock signal is transmitted from the terminal device located at the highest level among the normal terminal devices in the lower terminal device. The terminal device can perform the counting operation and the polarity detection operation. In addition, since the clock signal is also supplied from the higher-level terminal device to the higher-level terminal device than the failed terminal device, the count operation and the polarity determination operation can be performed in each terminal device. Therefore, one failure section (for example, when the terminal device LS2 fails, the terminal devices LS1-LS2
Even if the undeterminable section of (interval) is generated by one terminal device, the location of the accident point in the other section is performed normally,
The down state of the entire system due to the failure of one detecting device does not occur.

FIG. 4 is a diagram showing an example of a specific configuration of the terminal device shown in FIG. 3, and the same or corresponding parts as those of the terminal device shown in FIG. 2 are denoted by the same reference numerals. 4th
In the configuration shown in the figure, a clock source 200 that generates a clock signal of a predetermined frequency as a clock selection circuit S,
A clock detection circuit 201 for detecting a clock signal from the optical-to-electrical converter 101, and a clock signal from the optical-to-electrical converter 101 and a clock from the clock source 200 in response to the signal from the clock detection circuit 201. And a switching circuit 202 for selecting and outputting any of the signals. The output of the switching circuit 202 is used as a clock signal for the terminal device LS and the lower terminal device. That is, the clock signal from the switching circuit 202 is supplied to the lower terminal device in the form of an optical signal via the electro-optical converter 102, and is also used as a counter clock signal in the counters A and B inside the device. Can be

The clock detection circuit 201 determines that the higher-level device has failed if no clock signal has been supplied from the higher-level terminal device (terminal device or central monitoring station) for a predetermined time or longer, and determines whether the clock source 200 has failed. Is activated to generate a clock signal internally and to control the switching circuit 202 to output the clock signal from the clock source 200. As a configuration of such a clock detection circuit 201, a clock signal, that is, a clock signal from the optical-to-electrical converter 101 is counted, and a clock signal is supplied when it cannot be counted up to a predetermined number within a predetermined time. The configuration can be easily made by using a timer that determines that there is no such event. The switching circuit 202 may be configured using a simple multiplexer, and can be easily configured using a gate circuit.

Other configurations are the same as those shown in FIG. 2, and the start pulse from the counter A103 is transferred via the electro-optical converter 113 as a stop pulse in the upper device. The data multiplexing transmission unit 111 receives data from the lower terminal device via the electro-optical-electrical converter 114, multiplexes the data in the terminal device, and transmits the multiplexed data to the upper terminal device or a central monitoring station). The signal is transmitted through the electro-optical converter and the optical-electric converter 112, and further receives various control signals (for example, a reset signal) from a higher-level device, and is reset at the time of an erroneous determination operation due to surge noise or the like. .

In the above-described configuration, the clock source 200 is activated and generates a clock signal in response to a signal that detects that no clock signal is supplied from the clock detector 201. Instead, the clock source 200 is always operated, that is, kept in the oscillation state, and the switching circuit 202 is controlled only when the clock signal is not supplied from the host device for a predetermined time or more, and the clock signal from the clock source 200 is used. It may be.

2 and 4, in order to reduce the number of optical fibers used as signal transmission lines,
In order to transmit / receive a pulse for pulse delay correction and a clock pulse using the same fiber, a configuration may be adopted in which transmission / reception is performed by performing wavelength multiplexing.

In the above embodiment, the configuration for detecting the current flowing through the transmission line has been described. However, the present invention is applicable to an underground line instead.

In the above description, referring to FIG. 4, when the switching circuit 202 selectively switches the clock signal upon detecting that the upper device is in a failure state, the failure occurrence information is transmitted to each terminal device. A configuration may be provided in which the information is generated in the form of display or audio, and the failure information is given to the data multiplex transmission unit. By doing so, the system can be instantaneously restored in response to a failure in the terminal device, and the location of the failed station can be easily performed.

Further, although not specifically shown in the above description, it is preferable that all clock signals generated by the clock sources 100 and 200 have the same frequency. Thus, the counting operation of each counter B can be easily corrected without performing complicated processing.

[Effects of the Invention] As described above, according to the present invention, a clock generator is provided in each terminal device in the polarity determination type accident point locating device,
This clock generator is used to form a clock signal loop with two terminal devices as constituent units, or to provide a clock signal of the clock signal source to a lower terminal device when a failure occurs. The backup function can be provided, and even if one terminal device fails, its influence can be minimized, and the entire positioning device system can be prevented from being down. It is possible to realize a high accident point location system.

[Brief description of the drawings]

FIG. 1 is a diagram showing the concept of a polarity determination type accident point locating apparatus according to the present invention. FIG. 2 is a diagram showing an example of a specific configuration of a terminal device used in the polarity determination type accident point locating device shown in FIG. FIG. 3 is a view showing still another concept of the present invention. FIG. 4 is a diagram for embodying the concept of the invention shown in FIG. 3, and is a diagram showing an example of a specific configuration of the terminal device. FIG. 5 is a diagram schematically showing the configuration of a conventional accident point locating device. FIG. 6 is a diagram showing an improved example of the conventional accident point locating device, and is a diagram showing a principle configuration of the accident point locating device to which the present invention is applied. Seventh
FIG. 6 is a diagram for explaining the timing at which the operation of the polarity determination circuit and the timer of the fault point locating device shown in FIG. 6 is performed, and is a diagram showing the behavior of the transmission line current when an accident occurs in the transmission line. FIG. 8 is a diagram showing the principle of correcting the counter delay in the accident point locating device shown in FIG. FIG. 9 is a diagram illustrating an example of a case where an accident point locating device system is configured using the device configuration illustrated in FIG. 6, and is a diagram illustrating an example of a determination operation in the central device MS. In the figure, 100 and 200 are clock sources, 103 is a counter A for counting the number of clocks for deriving an accident occurrence point, 104 is a counter B for correcting a clock signal propagation delay, 108 is a data acquisition unit, and 110 is data holding. Part, 11
1 is a data multiplex transmission unit, 109 is a polarity determination circuit, 201 is a clock detector, 202 is a switching circuit, LS, LS1 to LS3 are terminal devices,
MS is a central monitoring station (master station), C1 to C3 and C10 to C13 are clock generators, and S is a backup clock selection circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (4)

(57) [Claims] 1. An accident is provided at each of a plurality of predetermined points on a power supply line, based on a surge current flowing through the power supply line when an accident occurs on the power supply line and a stable accident current following the surge current. An apparatus for locating a point of occurrence, comprising: a clock source for generating a clock signal; means for transmitting a clock signal from the clock source to a lower adjacent device; and a clock transmission included in the upper adjacent device. Counter means for receiving and counting a clock signal from the means, means provided for each device, means for detecting a current flowing through the power supply line, and in response to a surge current detection signal from the current detection means, Means for holding the count value of the counter means; means for determining the polarity of the fault current based on the fault current detection signal from the current detecting means; Means for transmitting the count value held by the means and the fault current polarity determined by the polarity determining means to a host device. 2. An apparatus according to claim 1, further comprising means for receiving information transmitted from each of said apparatuses and locating an accident point on said power supply line. 3. The apparatus according to claim 2, wherein each of the devices responds to an accident current detection signal from at least one of the current detection means provided corresponding to each of the plurality of points on the power supply line. 3. The polarity determination type fault point locating device according to claim 1, wherein each transmission means is configured to be activated. 4. A first clock source for generating a first clock signal instead of the clock source; a means for inputting a second clock signal transmitted from a higher-level adjacent device; Means for detecting whether or not a second clock signal is provided to the input means; and passing the second clock signal provided from the host device in response to the clock detection signal from the clock signal detection means. And a clock selecting means for passing a first clock signal in response to a clock non-detection signal from said clock detecting means, wherein an output of said clock selecting means is provided to said clock transmitting means. The polarity determination type accident point locating device according to claim 1.