JP2818248B2 - Fault location device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a fault point locating apparatus for locating an accident point at the time of an accident by using the voltage of each terminal of a multi-terminal transmission line. .

(Prior art) The fault location, which determines the distance to the fault point using the voltage and current at each terminal of the transmission line, is based on the condition that the remaining voltage at the fault point calculated from the voltage and current at both terminals is the same in a two-terminal system. It is implemented using. For example, it is shown on page 45 of Ohmsha's “Troubleshooting for Transmission Lines” published by Ohmsha in 1957.

According to this, in the system shown in FIG.
_F is the voltage ( _A , _B ), current ( _A , _B ) of both terminals,
Impedance Z and line length l of the per unit length of the line, represented by the following formula than the distance l _X to the fault point.

_F = _A − _A ·· l _X (1) _F = _B − _B · (l−l _X ) (2) _F is eliminated from equations (1) and (2) to obtain l _X And equation (3).

_A , _B , _A , _B , and _{A in} Equation (3) are all vector quantities. Here, since the phases of the voltage components are almost equal, they are obtained as scalar quantities. This method uses the fault voltage
_{Since F} is theoretically erased, there is no influence of the accident point resistance, and if the electric quantity at both ends can be measured with high accuracy, accurate orientation can be performed. However, when each electric quantity is treated as a scalar quantity in the equation (3), accuracy is obtained when there is no load current, but when there is a load current, a phase shift occurs between the voltage at both ends and between the currents at both ends, resulting in a large error. . For this reason, it is necessary to calculate the voltage and current at both ends with reference to the signal synchronized at both ends in the calculation of the expression (3). Recently, the following three methods have been adopted.

The first method is to connect between both terminals due to recent development of transmission technology.
This is a method of connecting by PCM transmission, transmitting and receiving a synchronization signal and creating a simultaneous reference signal at both ends. This method has already been put to practical use in a current differential relay in which transmission line protection is performed by a digital relay. However, this method has disadvantages that the transmission device is complicated and a large-capacity transmission line is required.

(For example, Japanese Patent Publication No. 57-50262) The second method is a method based on the point of change of the system at the time of the occurrence of an accident. Using this as a reference time point, the magnitude and phase of the voltage and current of each terminal are determined. In this case, the transmission of the voltage and current values (magnitude, phase) of each terminal is the first
There is an advantage that the transmission device can be simplified with a small capacity as compared with the above method. However, the change point detection at the time of occurrence of an accident means that the degree of change according to the position of the accident differs at each terminal,
Since the degree of change differs depending on the power supply condition behind the terminal and the change point in the case of multiple accidents is complicated, there is a drawback that the scale of the apparatus increases in order to increase the accuracy of change point detection. (For example, the paper "1304 digital type fault locator of the 1987 National Institute of Electrical Engineers of Japan," and the paper "1361 digital type fault locator of the National Institute of Electrical Engineers of 1987, the second." The method is to determine the voltage and current data of each terminal with reference to the voltage of each terminal (for example, a-phase voltage reference),
Thereby calculating the fault point voltage _(F) from each terminal, the distance is changed progressively until the fault point so that the fault point voltage calculated from the terminals become equal, the fault point to l _{X when F} matches It is a method. However, although this method is said to be asynchronous, the transmission device can be simplified,
There are drawbacks in that it becomes extremely complicated when expanding to a three-terminal system and a four-terminal system, and that an error increases. (For example, Showa
1977 National Institute of Electrical Engineers National Convention paper “Development of 1238 Digital Fault Locator (Results)” (Problems to be Solved by the Invention) As described above, the creation of reference amounts for each terminal voltage and current data requires a large capacity. There is a drawback that a transmission line is required, or the extension to a multi-terminal system is inferior in accuracy and the device becomes complicated.

In view of the above, it is an object of the present invention to provide a fault locating device which simplifies a transmission device for collecting data and does not complicate the device even in a multi-terminal system.

[Means for Solving the Problems] A fault locating device of the present invention uses a voltage and current data transmitted from a terminal device installed at each terminal of a multi-terminal power transmission line, and a central determination device. The terminal device comprises an input processing means, a receiving means, a data synchronizing means, a data freezing means, and a transmitting means, and the central determining apparatus comprises a receiving means, a branch point voltage calculation. Means, phase difference calculating means, SP (sampling) synchronization adjustment signal generating means, transmitting means, change detecting means, start command generating means, accident section discriminating means, and locating means.

(Operation) The present invention transmits the voltage and current data of each terminal from the terminal device to the central predetermined device, and uses the central determination device to check one of the terminals (main terminal) and the other terminal before the accident. The branch point voltage is calculated, and a sampling synchronization adjustment signal is transmitted to the terminal device based on the phase difference. The terminal device synchronizes the voltage and current data of each element with the sampling synchronization adjustment signal. In the event of an accident, a change is detected by the central determination device, a start command and a retroactive time are generated and transmitted to the terminal device. The terminal device freezes the voltage and current data for a predetermined time based on the start command, and transmits the central determination device. The central unit determines and locates an accident section from the voltage and current data from each terminal device.

Example An example of the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram in which a fault point locating device of the present invention is applied to a power system. Hereinafter, a four-terminal system will be described as an example. The voltages and currents of the terminals A to D in the target section for the fault location are calculated by the data generators 113, 123, 133, and 143 of the terminal devices installed at the respective terminals, and the respective transmitters 114, 1
The data is transmitted to the central determination device via the communication lines 24, 134 and 144. And
The central determination unit 201 performs a fault location operation using the voltage and current data transmitted from each terminal. In FIG. 1, A, B, C and D are terminal names, J ₁ and J ₂ are branch points, l _X is a line length of each section, and Z _X is an impedance per unit length.

An outline of the present invention will be described. First, each end of FIG.
Synchronize the electric quantities of A, B, C, and D at normal times (before the accident). That is, for example, with the main end as the A end and the sub ends as B, C, D ends, the electric quantity at the sub ends (B, C, D ends) is synchronized with the electric quantity at the main end (A end). Specifically, each terminal device transmits a voltage and a current to the central judgment device, and the branching point voltage viewed from the main terminal at the central judgment device (J ₁ for the B terminal, C ₁ terminal for the D terminal, Then, an apparent phase difference between J ₂ ) and the branch point voltage seen from the slave end is determined, a signal for adjusting the synchronization of sampling at each terminal (SP synchronization adjustment signal) is transmitted to each terminal. Each terminal device transmits the representative phase voltage and current sample value of its own terminal to the central determination device in synchronization with the received SP synchronization adjustment signal.

Second, the central determination device detects an accident, for example, detects a change in the branch point voltage as viewed from the main end, and sends a start command to each terminal. Each terminal device freezes the voltage and current data of all phases for a predetermined time in response to the start command and transmits the data to the central determination device.

Third, the central determination device determines an accident section based on the data received from each terminal device, performs a location calculation, and outputs a location result.

Next, the configuration and internal processing of the central determination device and the terminal device will be described with reference to the drawings.

FIG. 2 is a functional block diagram of the central determination device. From each terminal data (A / D converted value of the representative phase voltage and current) received by the receiving means 20, the branch point voltage calculating means 21 calculates the voltage at the branch point viewed from each terminal. Branch point voltage calculation means
Based on the output of 21, the phase difference calculating means 22 calculates the apparent phase difference of each terminal data. The SP (sampling) synchronization adjustment signal generating means is output by the output of the phase difference calculating means 22.
23 generates an SP synchronization adjustment signal and transmits it to each terminal by the transmission means 24. The change detecting means 25 determines from the output of the branch point voltage calculating means 21 whether or not there is a change in the branch point voltage (the presence or absence of a system fault). When the change detecting unit 25 detects the presence of the change, the start command generating unit 26 generates a start command, and the start command is transmitted to each terminal by the transmitting unit 24.

After transmitting the start command, each terminal data received by the receiving means 20 (the synchronized voltage of all phases of the time width required for orientation,
Based on the A / D conversion value of the current), the branch point voltage calculating means 21 calculates the voltage at the branch point. The fault section determination means 28 determines the fault section from each branch point voltage. The orientation means 29 calculates an orientation value from the voltage, current, and impedance, and outputs the result.

FIG. 3 is a flowchart showing the operation of the above-described central determination device. In FIG. 3, in step 221, the voltage and current data of the representative phase transmitted from each terminal are received. First, the A and B ends will be described. In step 222, the branch point voltage viewed from the main terminal (A terminal) is calculated as in equation (4).

However, m: a sampling time V _a: bus voltage a terminal I _a: line current of a terminal Z _a: a terminal and a unit length impedance l _a between branch points: Distance Next, steps between branch points and the terminals At 23, the branch point voltage as viewed from the slave end (end B) is calculated as in equation (5).

To the branch point J _1, However, n: Sampling time V _b: bus voltage terminal b I _b: line current of the terminal b Z _b: b terminal and unit length impedance l _b between branch points: In the terminal b and the distance step between branch points 224, The phase difference φ is calculated as follows.

First, a _{u m w n-3 -u m} -3 w n = UWsinφ ...... (6) u m w n + u m-3 w n-3 = UWcosφ ...... (7). Here, for example, when searching for n that maximizes the calculation result of equation (7), Where the apparent phase difference, that is, the angle at which the sampling time point n at the B end advances with respect to the m time point at the A end.

Next, an example of the four-terminal system shown in FIG. In step 222, it is calculated as in equation (9).

For junction J ₂ Also, in step 223, calculation is made as in equation (10). To the branch point J _2, As described in the equations (6) to (8), apparent phase differences (advance) φ _c , φ _d at the C and D ends with reference to the A end.
Is found.

In step 225, the phase differences φ and φ obtained in step 224
_c, phi each terminal _d on the basis of (B, C, D) with respect to transmit information corresponding to the phase difference as SP (sampling) synchronizing adjustment signal. Note that a phase difference = 0 is transmitted to the terminal A (main terminal).

In step 226, it is determined whether the accident on the magnitude relation between the change amount [Delta] V _J and constant K of the master end voltage branch point J ₁ as seen from (A end) (V _J). If there is no change (ΔV _J <K ₁ ), the process returns to step 221. When there is a change (ΔV _J K ₁ ), the process proceeds to step 227.

 In step 227, a start command is transmitted to each end.

At step 230, voltage and current data of all phases transmitted from each terminal is received. Next, at step 231, the branch point voltage for the example of the four-terminal system shown in FIG.
It is calculated as in the formula.

In step 232, it is determined whether or not the difference between each terminal voltage and the branch point voltage or between the branch point voltages is equal to or more than a predetermined value (K ₂ ). For example, When the judges fault section and between J ₁ and J ₂ in step 233.

In general, if p ≠ q is p ≠ q in any of a, b, c, d, J ₁ and J ₂ , the same relationship as equation (12) holds, and the accident section is p, q
It is determined to be between.

 At step 234, the orientation calculation is performed by the equation (13).

When the equation (12) is established, referring to FIG. Is calculated.

 At step 235, the orientation result x is output.

Next, the terminal device will be described with reference to the functional block diagram of FIG. The voltage of the terminal taken in by the input processing means 11,
Get the A / D conversion value of the current. The receiving means 12 receives an SP (sample) synchronization adjustment signal from the central determination device. The data synchronization means 13 synchronizes the data of the output of the input processing means 11 with the output of the reception means 12. The output (data and voltage data of the representative phase) of the data synchronizing means 13 is transmitted by the transmitting means 14 to the central determination device. Further, the receiving unit 12 receives a start command and a retroactive time from the central determination device. The data freezing means 15 freezes data for a predetermined time based on the start command of the output of the input processing means 11. That is, it is stored and no new update is performed. The output of the data freezing means 15 (voltage and current data of all phases) is transmitted by the transmitting means 14 to the central determination device.

FIG. 5 is a flowchart showing the operation of the terminal device described above. In step 301, the instantaneous values of the A / D-converted voltage and current are stored for a predetermined time (for example, 10 cycles), and unnecessary DC components and harmonic components included in the data are removed. In step 302, an SP (sampling) synchronization adjustment signal is received. In step 303, the sampling of the voltage and current data at the own end is synchronized with the sampling of the voltage and current data at the other end based on the SP synchronization adjustment signal.
Specifically, since the SP synchronization adjustment signal represents a sampling phase difference with respect to the main terminal, the sampling timing at the own end is adjusted so that the SP synchronization adjustment signal approaches zero.

In step 304, it is determined whether a start command has been received from the central determination device. If there is no start command, the process proceeds to step 305 to transmit the voltage and current data of the representative phase. Steps
When it is determined in 304 that there is a start command, in step 307, the voltage and current data are frozen for a predetermined time based on the start command. In step 308, voltage and current data of all phases (output of step 307) are transmitted to the central determination device.

Using the voltage and current of the representative phase before the accident obtained by the terminal device, the central judgment device calculates the branch point voltage seen by each terminal,
By transmitting the apparent phase difference of each branch point voltage to each terminal and synchronizing the sampling, a high-capacity transmission line is not required, and a high-precision fault location can be performed even in a multi-terminal system without complicating the equipment. It can be.

(A)-Transmission between the central determination device and the terminal device in the embodiment may be performed intermittently in order to reduce the transmission capacity. A functional block diagram in this case is shown in FIGS. 6 and 7.

FIG. 6 is a modified example of FIG. 1, in which the central determination device intermittently transmits the SP synchronization adjustment signal and the start command by the transmission means 24 at normal times. Further, the retroactive time generation means 27 obtains a predetermined time as the retroactive time plus “the time during which the transmission of the start command is delayed due to intermittent transmission during normal times”, and transmits it to the terminal device by the transmitting means 24.

FIG. 7 is a modification of FIG. 3, in which the terminal device intermittently receives the SP synchronization adjustment signal and the start command by the receiving means 12. Further, the receiving means 12 receives the retroactive time and outputs it to the data freezing means 15. The data freezing means freezes the data for a predetermined time from the timing of going back by the retroactive time from the start command.

 According to this example, the transmission capacity can be reduced.

(B) When synchronizing the voltage and current data of each terminal and correcting the integer cycle shift (phase difference) of the data, the transmission delay time between the central determination device and each terminal device is taken into consideration.

When the variation of the transmission delay with each terminal is less than one cycle, it is uneasy to consider the transmission delay time. In addition, since the purpose is to correct an integer cycle shift, the strictness of the transmission delay time is uncertain.

In this modification, the SP synchronizing signal generation means 23 is replaced with the SP synchronizing signal plus transmission delay time generating means in FIG. Send a signal. Also, in FIG.
Is replaced with the one that receives the SP synchronization adjustment signal and the transmission delay time. Then, the data synchronizing means 13 is replaced with a data synchronizing means which adjusts the timing to a point in time which is advanced by the transmission delay time in synchronization with the SP synchronization adjustment signal. Furthermore, data freezing means 15
Is replaced with the one that freezes the data for a predetermined time from the timing retroactive by the transmission delay time from the start command.

According to this example, it is possible to correct the integer cycle shift of each end data. Of course, a combination of the modified examples (a) and (b) can be easily inferred from the present invention.

(C) In the embodiment, the central determination device and the main end of the terminal device have been described as separate devices, but both may be configured as a single device for simplification of the device.

FIG. 8 shows a modification of FIG. 1, in which a central determination device is placed at terminal A at the main end, and the voltage and current at terminal A are directly input to the central determination device and are calculated by data creating section 113. There is no transmission unit (CCU) and transmission path for terminal A.

FIG. 9 is a modification of FIG. 2, in which the A / D converted values of the voltage and current of the main terminal (A terminal) taken in by the input processing means 11 are obtained. Further, the data freezing means 15 freezes data for a predetermined time from the output of the input processing means 11 based on the output of the start command generating means 26 (start command). Data freezing means 15
Is introduced into the branch point voltage calculating means 21.

FIG. 10 is a modification of FIG. 3, in which steps 301 and 307 (both are the same as in FIG. 5) are added.

According to this example, the central determination device and one of the terminal devices are integrated, and the overall device scale can be simplified.

[Effects of the Invention] The apparent phase difference between the branch point voltages seen by the main terminal and each slave terminal is determined using the representative phase voltage and current at each terminal before the accident, and sampling synchronization based on this phase difference is determined. For this purpose, a high-capacity transmission path is not required, and a high-precision fault locating can be performed without complicating the apparatus even with a large number of terminals.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram of the fault locating device of the present invention, FIG. 2 is a functional block diagram of the central determining device of the present invention, FIG. 3 is a processing flowchart of the central determining device of the present invention, and FIG. FIG. 5 is a functional block diagram of the terminal device of the present invention, FIG. 5 is a processing flowchart of the terminal device of the present invention, FIGS. 6 to 10 are diagrams for explaining another embodiment of the present invention, and FIG. FIG. 4 is a power system diagram to be described. 113, 123, 133, 143 Data creation unit 114, 124, 134, 144 Transmission unit (CCU) 201 Central judgment device 11, Input processing unit 12, 20 Reception unit 13, Data synchronization unit 14, 24 Transmission unit 15, ... Data freezing means 21 ... Branch point voltage creating means 22 ... Phase difference detecting means 23 ... SP synchronization adjustment signal generating means 25 ... Change detecting means 26 ... Start command generating means 28 ... Fault section determining means , 29 …… Orientation means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-249079 (JP, A) JP-A-2-74877 (JP, A) JP-A-2-84014 (JP, A) JP-A-1- 285872 (JP, A) JP-A-2-22574 (JP, A) JP-A-62-272163 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01R 31/08

Claims (3)

(57) [Claims] 1. A fault point locating device for locating a fault point of a transmission line by a central determination device using voltage and current data transmitted from a terminal device installed at each terminal of a multi-terminal transmission line. Receiving means for delivering current information; branch point voltage calculating means for calculating a branch point voltage at each terminal from the output of the receiving means; and phase difference calculation for calculating a phase difference from the output of the branch point voltage calculating means. Means, sampling adjustment signal generation means for generating a sampling adjustment signal from the output of the phase difference calculation means, transmission means for transmitting the output of the sampling adjustment signal generation means, and change from the output of the branch point voltage calculation means. Change detecting means for detecting, start command generating means for generating a start command from an output of the change detecting means, transmitting means for transmitting an output of the start command generating means, and receiving means A central determining device including an accident section discriminating means for discriminating an accident section from an output and an output of a branch point voltage calculation, and a locating means for locating an accident point; and input processing means for inputting terminal voltage and current information Receiving means for receiving the sampling synchronization adjustment signal, data synchronizing means for synchronizing data from the output of the input processing means and the output of the receiving means, the receiving means for receiving the start command, A terminal device comprising: data freezing means for freezing (storing and not updating) data for a predetermined time from an output of the means based on a start command, and transmitting means for transmitting outputs of the data synchronizing means and the data freezing means. A fault point locating device comprising: 2. A method according to claim 1, further comprising a retroactive time generating means for obtaining a retroactive time by adding a predetermined time and a time when the start command is delayed for intermittent transmission during normal times. A central determining device in which the transmitting means intermittently transmits a sampling synchronization adjustment signal, a start command and a retroactive time, and a receiving means in which the receiving means intermittently receives a sampling synchronous adjustment signal, a start command and a retroactive time. A terminal device that freezes data from a timing retroactive by a retroactive time from a start command as a starting point. 3. The apparatus according to claim 1, wherein said sampling synchronization adjustment signal generating means is means for generating a sampling synchronization adjustment signal and a transmission delay time, and said transmitting means is a sampling synchronization adjustment signal and a transmission delay time. And a central determination device that transmits a start command, and a receiving unit that receives a sampling synchronization adjustment signal, a transmission delay time, and a start command, and a data synchronization unit that goes back by a transmission delay time with respect to the sampling period adjustment signal. And a terminal device for synchronizing data at a time point, and having a terminal device that freezes data from a timing retroactive by a transmission delay time from a start command to a data freezing means. Orientation device.