JP2016142659A - Failure point locating method and failure point locating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a failure point location method and the like capable of locating a failure point after determining a propagation speed of a surge with as little facilities as possible.SOLUTION: A failure point locating method includes: acquiring a first time at which a direct wave of a surge generated at a failure point reaches a first arrival point present on the side of a supply part from the failure point; acquiring a second time at which the direct wave reaches a second arrival point present on the side of a line terminal part from the failure point; acquiring a third time at which a reflected wave of the surge reflected at the line terminal part reaches the second arrival point; calculating a propagation speed of the surge on the basis of a time difference between the second time and the third time, and a transmission path length from the second arrival point to the line terminal part; and locating the failure point on the basis of the propagation speed of the surge, a transmission path length between the first arrival point and the second arrival point, and the first time and the second time.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a fault location method and a fault location system.

  Each of the slave stations provided in the power transmission / distribution path in order to locate a fault point such as a ground fault in a path for supplying power using a power transmission / distribution line (hereinafter referred to as a power transmission path) A fault location system is known that detects a surge (current or voltage) and identifies a fault point based on the time when the surge is detected at each slave station (for example, Patent Document 1). In order to more accurately locate a failure point with such a failure point location system, it is necessary to more accurately determine the propagation speed of the surge from the failure point. For this reason, a method for obtaining the propagation speed of surge is known (for example, Patent Document 2).

Japanese Patent No. 3527432 Japanese Patent No. 4039576

  However, in the method described in Patent Document 2, it is necessary to use three or more slave stations to calculate the propagation velocity of surge. For this reason, there has been a problem that the cost of constructing a system having equipment for calculating the propagation speed of surge is high and the threshold for introduction is high. In addition, in the conventional method, when the number of slave stations that can be used for the propagation speed of the surge with respect to the failure point becomes 2 or less, the propagation speed of the surge cannot be obtained, and it is difficult to determine the failure point. There was a problem of becoming.

  Accordingly, an object of the present invention is to provide a failure point locating method and a failure point locating system capable of locating a failure point after obtaining a propagation speed of a surge with fewer facilities.

  In order to solve the above-described problems and achieve the object, the present invention provides a fault in a transmission path provided between a supply unit that supplies power and a line end that is supplied with power from the supply unit. A failure point locating method for locating a failure point when occurring, wherein a direct wave of a surge generated at the failure point reaches a first arrival point existing on the supply unit side from the failure point. The time is acquired, the second time when the direct wave reaches the second arrival point existing on the line end side from the failure point is acquired, and the reflected wave of the surge reflected at the line end is obtained. The third time when the second arrival point is reached is obtained, and the time difference between the second time and the third time and the transmission path length from the second arrival point to the line end are obtained. The surge propagation speed is calculated based on the surge propagation speed, the previous Based on the first transmission path length and the first time and the second time between the arrival point and the second arrival point for locating the fault point.

As a desirable mode of the present invention, when the transmission path length from the second arrival point to the line end is L, and the time difference between the second time and the third time is t, the following formula ( The surge propagation velocity v between the second reaching point and the line end is calculated by 1).
v = 2L / t (1)

  In order to solve the above-described problems and achieve the object, the fault location system of the present invention is provided between a supply unit that supplies power and a line end that is supplied with power from the supply unit. A first acquisition device for acquiring a first time when a direct wave of a surge current flowing from the failure point reaches a first arrival point existing on the supply unit side from the failure point when a failure occurs in the transmission line; The reflected wave of the surge current reflected at the second time point when the direct wave reaches the second arrival point existing on the line end side from the failure point and the line end part reaches the second arrival point. Based on the second acquisition device for acquiring the reached third time, the time difference between the second time and the third time, and the transmission path length from the second arrival point to the end of the line Calculate the propagation speed of the surge current and An arithmetic processing unit that locates the failure point based on a carrying speed, a transmission path length between the first arrival point and the second arrival point, and the first time and the second time; .

  As a desirable mode of the present invention, the first acquisition device and the second acquisition device each include a time synchronization unit that synchronizes the current time measured by each.

  As a desirable mode of the present invention, the time synchronization unit synchronizes the current time using time data included in the GPS signal.

  According to the present invention, the failure point can be determined after obtaining the propagation speed of the surge with less equipment.

FIG. 1 is a diagram illustrating an example of a main configuration of a fault location system. FIG. 2 is a diagram illustrating an example of a main configuration of a slave station. FIG. 3 is a schematic diagram illustrating an example of a configuration provided in the power transmission system. FIG. 4 is a diagram illustrating an example of a main configuration of the master station. FIG. 5 is a flowchart showing an example of a main processing flow related to the fault location. FIG. 6 is a diagram illustrating an example of a correspondence relationship between the frequency component of the surge waveform and the propagation speed of the surge. FIG. 7 is a schematic diagram illustrating an example of data regarding capacitance.

(Embodiment)
Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating an example of a main configuration of the failure point location system 1. As shown in FIG. 1, the fault location system 1 includes a plurality of slave stations 10 and a master station 20. The slave station 10 is provided in a power transmission system that connects the power supply unit 30 and the line end E. The supply unit 30 is a facility such as a power plant or substation of an electric power company, for example. However, the supply unit 30 is not limited to this, and corresponds to the supply unit 30 as long as power is supplied to the line end E. Yes. The line end E refers to the end of the power transmission system in an open state.

  FIG. 2 is a diagram illustrating an example of a main configuration of the slave station 10. The slave station 10 detects an electrical waveform (hereinafter, surge waveform) generated by a surge generated at the failure point B (see FIG. 3). The slave station 10 transmits the time when the waveform is generated to the master station 20 as “the time when the surge current reaches the position where the slave station is provided”. Specifically, the slave station 10 includes, for example, a time synchronization unit 11, a surge waveform detection unit 12, a transmission unit 13, and the like.

  The time synchronization unit 11 performs a process for synchronizing the current time measured by each slave station 10. Specifically, the time synchronization unit 11 includes, for example, a digital clock circuit that measures the current time, an antenna that receives a signal (GPS signal) from a satellite of a global positioning system (GPS), a GPS signal, Includes a time correction unit for correcting the current time measured by the digital clock circuit based on the time data included in Since each slave station 10 has the time synchronization unit 11, the time counted by each slave station 10 is unified with the current time indicated by the time data included in the GPS signal.

  The surge waveform detector 12 detects a surge waveform. Specifically, the surge waveform detector 12 is, for example, a zero-phase-sequence current transformer (ZCT), the arrival of the surge waveform and the arrival direction of the surge waveform according to the current detected by the ZCT. And a signal output circuit for outputting a detection signal indicating. When the surge current reaches the slave station 10, a current indicating a surge waveform flows through the ZCT. The surge waveform detection unit 12 outputs a detection signal to the transmission unit 13 when a current indicating a surge waveform flows through the ZCT.

  The transmission unit 13 transmits to the master station 20 data indicating the time when the surge current reaches the position where the slave station 10 is provided and the arrival direction of the surge current. The transmission unit 13 includes, for example, a time acquisition unit that acquires the time when the detection signal is output from the surge waveform detection unit 12 from a digital clock circuit, a reception unit 21 that transmits and receives data to and from the master station 20, and the like. The surge information Sig indicating the arrival time of the surge current indicated by the time acquired by the time acquisition unit and the detection signal is transmitted to the master station 20. The receiving unit 21 of the present embodiment communicates with the master station 20 by wireless communication, but the specific form of communication is arbitrary.

  FIG. 3 is a schematic diagram illustrating an example of a configuration provided in the power transmission system. Two or more slave stations 10 are provided in one power transmission system. Specifically, as shown in FIG. 3, for example, the power transmission system between the supply unit 30 that supplies power and the line end E to which the power from the supply unit 30 is supplied has a relatively supply unit. There is a slave station 10 (first slave station 10A) provided on the side 30 and a slave station 10 (second slave station 10B) provided on the line end E side relatively.

  FIG. 4 is a diagram illustrating an example of a main configuration of the master station 20. The master station 20 performs various arithmetic processes for locating the failure point B based on the data from the slave station 10. Specifically, the master station 20 includes, for example, a reception unit 21 and an arithmetic processing unit 22. The receiving unit 21 includes, for example, an antenna and other communication devices, and performs various communications such as reception of surge information Sig transmitted from the slave station 10. The arithmetic processing unit 22 includes an arithmetic processing circuit such as a CPU, and a storage device such as a RAM, a ROM, and a flash memory, and malfunctions based on data input via the reception unit 21 and data stored in the storage device. Various arithmetic processes related to the orientation of the point B are performed.

The storage device of the present embodiment has a transmission path length (L _a ) between the first arrival point and the second arrival point and transmission from the second slave station 10B to the line end E (see FIG. 3). Data indicating the path length (L) is stored.

  Next, the location of a failure point (for example, the failure point B in FIG. 3) by the failure point location system 1 will be described. In the power transmission system shown in FIG. 3, when a fault with a ground fault occurs at a position between the first slave station 10 </ b> A and the second slave station 10 </ b> B, that position becomes the fault point B, and the surge current is Propagate to the supply unit 30 side and the line end E side.

  The surge current propagated to the supply unit 30 side reaches the first slave station 10A as a direct wave of surge. The first slave station 10 </ b> A detects the surge current propagated to the supply unit 30 side and transmits surge information Sig (first information) to the master station 20. In this case, the position where the first slave station 10 </ b> A where the surge current has reached is the first arrival point located on the supply unit 30 side from the failure point B. Moreover, 1st information shows the 1st time when the direct wave of surge arrived at the 1st arrival point. The first slave station 10A functions as a first acquisition device. The master station 20 receives the first information transmitted from the first slave station 10A in response to the direct wave of surge.

  The surge current propagated to the line end E side first reaches the second slave station 10B as a direct surge wave. The second slave station 10B detects the surge current propagated to the line end E side and transmits surge information Sig (second information) to the master station 20. In this case, the position where the second slave station 10B where the surge current has reached is the second arrival point located on the line end E side from the failure point B. Moreover, 2nd information shows the 2nd time when the direct wave of surge arrived at the 2nd arrival point. The second slave station 10B functions as a second acquisition device. The master station 20 receives the second information transmitted from the second slave station 10B in response to the direct wave of surge.

The surge current propagated to the line end E side passes through the second arrival point, is reflected by the line end E, and reaches the second slave station 10B as a reflected wave. Specifically, when the surge impedance of the power transmission system is Z1, and the surge impedance of the line end E is Z2, the reflection coefficient α of the surge current can be calculated by the following equation (2). Since the line end E is in an open state, Z2 = ∞. For this reason, the reflection coefficient α obtained by the equation (2) is substantially “1”. That is, the surge current is totally reflected at the line end E.
α = (Z2−Z1) / (Z2 + Z1) (2)

  The second slave station 10B detects a surge current that has arrived due to reflection, and transmits surge information Sig (third information) to the master station 20. In this case, the third information indicates the third time when the reflected wave of the surge reaches the second arrival point. The master station 20 receives the third information transmitted from the second slave station 10B in response to the surge reflected wave.

  Whether the surge current reaching the second slave station 10B is a direct wave or a reflected wave depends on whether the direct wave reaches the second slave station 10B earlier, the arrival direction of the direct wave, and so on. The arrival direction of the reflected wave is opposite, the arrival direction of the surge current indicated by the surge information Sig output from the first slave station 10A, and the surge current indicated by the surge information Sig output from the second slave station 10B It can be distinguished by the relationship with the direction of arrival.

The master station 20 calculates the propagation speed of the surge based on the time difference between the second time and the third time and the transmission path length between the second arrival point and the line end E. Specifically, the arithmetic processing unit 22 of the master station 20 determines the second time and the third time from the time difference between the surge current arrival time indicated by the second information and the surge current arrival time indicated by the third information. The time difference (t) is calculated. In addition, the arithmetic processing unit 22 reads out data indicating the transmission path length between the second slave station 10B and the line end E from the storage device, and between the second arrival point and the line end E. The transmission path length (L) is specified. The arithmetic processing unit 22 calculates the propagation velocity (v) of the surge between the second arrival point and the line end E by the equation (1). “2L” in Equation (1) indicates that the reflected wave reciprocates between the second arrival point and the line end.
v = 2L / t (1)

The arithmetic processing unit 22 locates the failure point B based on the surge propagation speed, the transmission path length between the first arrival point and the second arrival point, and the first time and the second time. Specifically, the arithmetic processing unit 22 determines the transmission path length (L ₁ ) between the failure point B and the first slave station 10A and the failure point B based on the following equations (3) and (4). The failure point B is specified by calculating at least one of the transmission path lengths (L ₂ ) between the second slave stations 10B. In the expressions (3) and (4), t1 and t2 indicate the first time and the second time, respectively. Equations (3) and (4) indicate that the failure point B exists at the intermediate point (L _a / 2) between the first slave station 10A and the second slave station 10B if t1 = t2. ing. Further, in the equations (3) and (4), if t1 ≠ t2, the failure point B corresponds to the time difference between t1 and t2 from the intermediate point between the first slave station 10A and the second slave station 10B. In other words, it is located at a position shifted by half the propagation path length of the surge. The unit of time indicated by (t1-t2) and (t2-t1) (for example, microseconds [μs]) and surge propagation speed (v) (for example, microseconds per meter [m / μs]) It is assumed that the unit of time used to indicate is unified. Also, the length unit used to indicate the propagation speed (v) of the surge and the length used to indicate the transmission path length (L _a ) between the first arrival point and the second arrival point. The unit of length shall be unified.
L ₁ = {L _a + (t1−t2) v} / 2 (3)
L ₂ = {L _a + (t2−t1) v} / 2 (4)

  FIG. 5 is a flowchart showing an example of the main processing flow related to the fault point B orientation. When a failure occurs between the first slave station 10A and the second slave station 10B, a surge propagates from the failure point B. The first slave station 10A transmits to the master station 20 first information including information indicating a first time at which a surge waveform due to a surge direct wave is detected (step S1). The second slave station 10B transmits second information including information indicating the second time when the surge waveform due to the direct surge wave is detected to the master station 20 (step S2). The second slave station 10B transmits third information including information indicating the third time when the surge waveform due to the reflected wave of the surge is detected to the master station 20 (step S3). The processing order of step S1, step S2, and step S3 is the processing order corresponding to the positional relationship between the failure point B and each slave station. However, the process of step S3 is always the process after the process of step S2.

The master station 20 acquires the first time, the second time, and the third time from the first information, the second information, and the third information, respectively (step S4). The arithmetic processing unit 22 of the master station 20 generates a surge based on the time difference (t) between the second time and the third time and the transmission path length (L) from the second slave station 10B to the line end E. The propagation speed is calculated (step S5). The arithmetic processing unit 22 determines the failure point B based on the propagation speed of the surge, the transmission path length (L _a ) between the first arrival point and the second arrival point, and the first time and the second time. Orientation is performed (step S6). As described above, the master station 20 including the arithmetic processing unit 22 functions as an arithmetic processing device.

  FIG. 6 is a diagram illustrating an example of a correspondence relationship between the frequency component of the surge waveform and the propagation speed of the surge. With reference to FIG. 6, the reason why the surge propagation speed is obtained when determining the failure point B will be described. The surge propagation speed varies depending on the frequency component (band) of the surge waveform. In the example shown in FIG. 6, when the band is 0.05 [kHz] under the same predetermined conditions other than the band, the surge propagation speed is 220 [m / μs], and the band is 1 [kHz]. When the propagation speed of the surge is 244 [m / μs], the band is 10 [kHz], the propagation speed of the surge is 260 [m / μs], and the band is 50 [kHz]. This shows that the surge propagation speed is 273 [m / μs]. The band of surge is not constant and can be different at each failure.

  The surge propagation speed is also affected by the capacitance in the propagation path. FIG. 7 is a schematic diagram illustrating an example of data regarding capacitance. The storage device of the present embodiment stores data relating to the capacitance of the power transmission system. Specifically, the storage device stores, for example, data indicating the number of transformers and switches and the capacitance of each of the transformers and switches. The data shown in FIG. 7 is obtained by using one pole switch SW having a ground capacitance of 150 [pF] between the second slave station 10B and the line end E in the power transmission system shown in FIG. pF] indicates that there is one pole transformer T having a ground capacitance of [pF].

  The surge propagation speed calculated by equation (1) is the surge propagation speed between the second arrival point and the line end E, and passes through the second arrival point, the line end E, and between them. It is influenced by the electrostatic capacitance in the propagation path of the reflected wave. In the example shown in FIG. 3, one pole transformer T (2000 [pF]) and one pole switch SW (150 [pF]) exist in the propagation path of the reflected wave.

The propagation speed (v) of the surge can be expressed as the following formula (5) when generalized. In Expression (5), ω represents the angular frequency of the surge, and can be expressed as Expression (6). In Expression (6), f is a surge frequency. Further, β in the equation (5) is a phase constant. The phase constants are the capacitance (C) in the surge propagation path, the inductance (I) in the surge propagation path, the line resistance (R) in the surge propagation path, the line conductance (G) in the surge propagation path, and the surge It is determined based on the angular frequency (ω).
v = ω / β (5)
ω = 2πf (6)

If the surge propagates in the lossless distributed constant circuit ignoring the line resistance (R) and the line conductance (G), the propagation speed can be expressed as the following equation (7).

  As described above, the propagation speed of the surge represented by the equation (5) depends on the angular frequency (ω) of the surge, that is, the surge frequency (f). The frequency (f) of the surge can be different for each failure. For this reason, the propagation speed of the surge can be different for each failure. Therefore, even if the propagation speed of the surge at the time of the actual failure becomes different even if the propagation speed of the surge is estimated only by the estimation of the propagation speed of the surge by simulation of the failure and the preliminary verification with a predetermined pulse current, Failure point location errors can occur. Therefore, as in this embodiment, when a failure occurs, the surge propagation speed can be determined more accurately by determining the surge propagation speed in the failure with the actual propagation path. Point B can be located.

  As described above, according to the present embodiment, if the configuration for detecting the arrival of a surge (for example, the second slave station 10B) is at the second arrival point, the propagation speed of the surge can be calculated. That is, only one facility (for example, the slave station 10) for calculating the propagation speed of surge is sufficient. Therefore, the cost of the facility for calculating the propagation speed of surge can be further reduced. Further, according to the present embodiment, the failure point B is determined based on the propagation speed of the surge, the transmission path length between the first arrival point and the second arrival point, and the first time and the second time. Therefore, the failure point B can be determined after obtaining the propagation speed of the surge.

  Moreover, the calculation of the propagation velocity of surge can be further simplified by using the equation (1).

  Further, according to the present embodiment, only one slave station 10 is required for calculating the propagation velocity of surge. For this reason, since the present embodiment requires only one slave station 10 as compared to the conventional case where three or more slave stations are required for a failure point where the occurrence location is uncertain, it is more reliable. In addition, the propagation speed of surge can be calculated. Also, since the number of necessary slave stations 10 is sufficient for the fault point location, the fault point can be more reliably determined.

  As mentioned above, although embodiment was described, this invention is not limited by the content of these embodiment. In addition, the above-described constituent elements include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the above-described components can be appropriately combined. Furthermore, various omissions, substitutions, or changes of the components can be made without departing from the spirit of the above-described embodiment.

  For example, synchronization of the current time using the GPS signal by the time synchronization unit 11 is merely an example of a method for synchronizing the current time of the slave stations 10 to each other. The time synchronization unit 11 may synchronize the current time between the slave stations 10 by other methods. For example, the current time may be synchronized using a standard radio wave indicating standard time. Other configurations may also be realized by other specific configurations that satisfy the functional requirements.

  Further, the configuration affecting the capacitance is not limited to the pole transformer T and the pole switch SW. Any configuration provided in the power transmission system and having a ground capacitance can affect the propagation speed of the surge.

DESCRIPTION OF SYMBOLS 1 Fault location system 10 Slave station 10A 1st slave station 10B 2nd slave station 11 Time synchronization part 12 Surge waveform detection part 13 Transmission part 20 Master station 21 Reception part 22 Arithmetic processing part 30 Supply part B Failure point E Line Terminal SW Switch on pole T Switch on pole

Claims (5)

A failure point locating method for locating a failure point when a failure occurs in a transmission line provided between a supply unit that supplies power and a line end part to which power from the supply unit is supplied,
Obtaining a first time when a direct wave of a surge generated at the failure point reaches a first arrival point existing on the supply unit side from the failure point;
Obtaining a second time at which the direct wave has reached a second arrival point existing on the line end side from the failure point;
The third time when the reflected wave of the surge reflected at the end of the line reaches the second arrival point is acquired,
Calculate the surge propagation speed based on the time difference between the second time and the third time and the transmission path length from the second arrival point to the end of the line,
The failure point is determined based on the propagation speed of the surge, the transmission path length between the first arrival point and the second arrival point, and the first time and the second time. Method. When the transmission path length from the second arrival point to the end of the line is L and the time difference between the second time and the third time is t, the second equation is expressed by the following equation (1). The failure point locating method according to claim 1, wherein a surge propagation velocity v between the arrival point and the line end is calculated.
v = 2L / t (1) When a failure occurs in a power transmission path provided between a supply unit that supplies power and a line end that is supplied with power from the supply unit, a direct wave of a surge current that flows from the failure point is the failure point. A first acquisition device for acquiring a first time at which the first arrival point on the supply unit side is reached;
A second time when the direct wave reaches the second arrival point existing on the line end side from the failure point and a reflected wave of the surge current reflected at the line end point reaches the second arrival point. A second acquisition device for acquiring the third time,
The surge current propagation speed is calculated based on the time difference between the second time and the third time and the transmission path length from the second arrival point to the line end, and the surge current propagation speed. A failure point comprising: a transmission path length between the first arrival point and the second arrival point; and an arithmetic processing unit for locating the failure point based on the first time and the second time. Orientation system. The fault location system according to claim 3, wherein each of the first acquisition device and the second acquisition device includes a time synchronization unit that synchronizes a current time measured by each. The fault location system according to claim 4, wherein the time synchronization unit synchronizes the current time using time data included in a GPS signal.

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