JP2001013196A - One terminal decision type accident point estimation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately estimate an accident point of a power line having a branch line. SOLUTION: A slave station 110 is set to a branch terminal 134 branched from power lines 101, 102, while a master station 112 having a one terminal type accident point estimation device (FL) is set to a terminal 130. When a power line accident occurs, the slave station 110 and the master station 112 respectively take in voltage and current from their own terminals 134, 130, and detect the occurrence of the accident, such as a ground fault, a short circuit or the like, from the voltage states. The slave station 110 transmits an accident detection signal and the branch terminal current to the master station 112 through an exclusive line 114. The master station 112 synchronizes an abnormality detection signal of its own terminal 130 with the abnormality detection signal received from the slave station 110, and estimates an accident point by use of the synchronized its own terminal current and branch terminal current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accident point evaluation device for determining one end of a transmission line, and more particularly to a multi-terminal transmission system.
The present invention relates to an accident point rating device capable of performing a highly accurate rating even when a power supply or a load exists in a branch line.

[0002]

2. Description of the Related Art A conventional one-end determination type fault locating device estimates current sneak current at a branch end based on a self-end current and a branch line impedance, provided that there is no power at the branch end.
Accident point rating calculation is performed using this estimated value. In addition, a setting value that is assumed in advance is provided for the branch end load, and the accident point rating calculation is fixedly corrected.

[0003] Such an accident point locating device includes an impedance method for obtaining a fault point by dividing a voltage drop from a self end to a fault point by a voltage drop per unit length of a transmission line, and an impedance system for obtaining a fault point from the self end to a fault point. There is a reactive power method for finding a fault point from the ratio of the reactive power per unit length to the reactive power per unit length.

[0004] As an example of the former, JP-A-60-20422
In No. 0, the measured value of the current of the transmission line is distributed at the ratio of the set value to estimate the current of each branch load, and the estimated value is sequentially subtracted from the current at the sending end to be regarded as the current of each section, thereby The influence of the branch load is removed, the voltage drop per unit length in each section is obtained, and the distance to the fault point is calculated.

[0005] As an example of the latter, Japanese Patent Publication No. 7-1295 takes in the current and voltage of each phase after the occurrence of a fault at the FL installation end, and converts the reactive power from these values to the fault point of the fault phase into the fault point. The reactive power is calculated as the reactive power between the voltage and the zero-phase current (the sum of the phase currents). The reactive power per unit length is determined from the self and mutual impedances of the faulty phase and the current. At this time, a set value is used for the branch load current. less than,
This method will be supplementarily described with reference to the power transmission system diagram of FIG.

[0006] A load 7 and a branch load 8 are connected to a transmission line 1 in which one three-phase AC circuit is represented by a single line, and power is supplied from a power supply 6. Fault locator (FL) 100 is CT2,
The current value and voltage value of the transmission line 1 are taken in from PT3. FL
Is the installation point P0, the connection point P2 of the load 8, and the failure point F, the distance LF from P0 to _F is a value to be obtained. I _L is a current flowing through the load 7, and I _L2 is a current flowing through the branch load 8. In addition,
The distance L ₁ is P0 from P2, the distance L _F2 is over the length of F from P2.

Now, at the point F, an a-phase ground fault occurs, and P
The input signal voltages from T3 are Va, Vb, Vc, and the input signal currents from CT2 are Ia, Ib, Ic. At this time,
Reactive power Q _F of the zero-phase current I ₀ of the installation point P0 on the basis from the point P0 to the branch point P2 is obtained in the (1) formula. Note that I ₀ is given by equation (2).

[0008]

(Equation 1)

Here, R ₁ is the positive-phase resistance of the section L ₁ , X ₁
Positive-phase reactance of the section L ₁ is, I _L2 is branched load positive phase current, (1) the second term on the right side, the third term is a branch load current I
_{In the} correction term by _L2 , the effective value is obtained by integration. Here, t is the signal capture time, T is the cycle of the system power supply,
The phase of T / 4 indicates an invalid component.

The reactive power Q _{U based} on the zero-phase current per unit length (for example, 1 km) with the line constant of the transmission line 1 as a uniform distribution is given by equation (3). The voltage drop V _au per unit length of the a-phase is given by equation (4).

[0011]

(Equation 2)

Here, R _aa , R _ab , and R _ac are resistance values per unit length between a phase, ab phase, and ac phase, X _aa , X _ab , X _ac
Is also a reactance value. The voltage drop by the equation (4) is obtained by correcting each phase current with the branch load current _IL2 . Note that a in the equation is an operator that gives I _L2 a 120 ° delay (3 / T in time), and a ² gives I _L2 a 240 ° delay.

From this, the orientation value L _F is obtained from the equation (5) as the ratio between Q _F and Q _U.

[0014]

(Equation 3)

[0015]

As described above, in the conventional fault locating device for one end determination of a transmission system having a branch end, the branch load current of the correction term is set in advance as load operating value data. . For this reason, as the difference between the load current actually energized at the time of occurrence of the accident and the input set value increases, the error of the accident point location calculation increases.

It is an object of the present invention to provide an accident point evaluation apparatus which can solve the conventional problems when a branch line has a load or a power supply, performs an accident point evaluation with high accuracy, and can be simply configured. is there.

[0017]

In order to achieve the above object, the present invention relates to an apparatus for determining one end of a transmission line having a branch line terminal and an accident point estimating apparatus for a multi-terminal transmission line. In the provided master station, the installation end side current detection means,
Installation end side accident detection means and accident point locating calculation means, branch end side current detection means and branch end side accident detection means are provided in the slave station provided on the branch line terminal side, respectively, when an accident of the transmission line occurs, The master station fetches the accident detection data by the installation end side accident detection means and the installation end current data by the installation end side current detection means, and the slave station detects the accident by the branch end accident detection means. The slave station fetches the data and the branch end current data from the branch end side current detecting means, and transmits the accident detection data and the branch end current data from the slave station to the master station. The station synchronizes based on both the fault detection data, and the fault point locating means performs fault point locating using the synchronized installation-end current data and branch-end current data. One-end judgment type accident point rating device.

Further, the branch end side fault detecting means is characterized by using an undervoltage relay and a ground fault overvoltage relay. According to this, the voltage state of the branch end is taken in,
Transmission line accidents can be easily detected from the branch end side. In addition, the installation end side accident detection means can be similarly configured. However, when a protection relay device that detects an accident and shuts off the CB is separately provided, the accident detection data may be used.

Further, the branch end current data transmitted from the slave station to the master station determines an effective value from data taken in at least one power supply cycle after the occurrence of the accident, and transmits the effective value. It is characterized by the following. Thereby, transmission data can be compressed, and a low-speed telephone line can be used for the transmission line from the slave station to the master station.

According to the present invention, the accuracy of the fault point evaluation can be improved by using the current data of the branch line.
Further, by transmitting the fault detection data on the branch line, it is possible to easily secure the simultaneousness of the branch line current and the transmission line current data at the installation end.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a power system to be protected according to an embodiment of the present invention. Between the terminal 130 and the terminal 132, a 1L transmission line 101, a 2L transmission line 102
Are provided, and branch lines 103 and 104 are provided to the terminal 134 from the middle of each system. 1L, 2L
Although the system is shown by a simple line, each of the three phases (a, b,
c). The terminal 130 is provided with a generator 105 as a power source, and the branch terminal 134 is also provided with the generator 106. A switch (C
B) 121 to 126 are provided, which are opened by a command from a protection relay provided separately when a system fault occurs, and are closed again after a lapse of a re-closing time.

The one-end determination type accident point locating apparatus of this embodiment is as follows.
The terminal 130 is provided with a master station 112, and the branch end 134 is provided with a slave station 110. The master station 112 has a CT 14 of a 1L or 2L system.
From each of 0, 141 and PT 144, 145
Phase current data and three-phase voltage data are input. Also,
The slave station 110 also receives three-phase current data and three-phase voltage data from the CTs 142 and 143 and PTs 146 and 147 of the 1L and 2L systems, respectively. Then, current data and the like at the branch terminal 134 are transmitted from the slave station 110 to the master station 112 via the dedicated line 114.

FIG. 2 shows a system configuration of the one-end determination type accident point locating apparatus. In this system, branch line data is transmitted from the slave station 112 provided at the branch end, received by the master station 112 provided at one end of the multi-terminal power transmission system, and the one-end type fault locating device 220 in the master station is branched. The accident point is located using the line data. The slave station 112 is a branch end 1 of a 1L or 2L system.
34, the current state data, etc.
, And these data are sent to the communication device 205 via the modem 203. Communication device 205 transmits data to master station 112 using dedicated line 114. Dedicated line 1
14, a normal 4W system (two transmissions,
(Two serial transmissions) are used.

In the master station 112, the communication station 207 uses the slave station 11.
When the data from 0 is received, the current detection circuit 211 outputs the current data at the branch end 134 via the modem 209. Then, the AND circuit 213 determines that no abnormality detection signal is output from the communication abnormality detection device 212, and outputs the current state data of the 1L and 2L systems from the branch end current circuit 214 to the one-end type fault point locating device 220. Output to

The fault point locating device 220 is an FL starting circuit 221 for activating a fault point locating operation when a system abnormality occurs.
And an accident point locating operation circuit 222 for inputting current state data and the like of the accident system (1L or 2L) from the self-end data detection circuit 216 to perform accident point locating. The system abnormality detection circuit 215 is simply configured with 27 relays and 64 relays that detect an abnormal voltage state at the terminal.

The fault point locating operation circuit 222 performs a fault point locating operation based on the current state of the terminal and the set value of the branch end current. Further, a corrected fault point locating is performed using the actually measured value of the current state of the branch end 134 received from the slave station 110.
A correction operation circuit 223 is provided. As a result, since it is possible to perform the location calculation in consideration of the sneak current at the branch end, it is possible to more accurately locate the fault point than the conventional one-side determination type location device using the set value at the branch end. Although the fault point locating calculation according to the present embodiment is based on the above-described reactive power method, it can be applied to an impedance method.

FIG. 3 shows a detailed processing configuration of taking and transmitting branch end data in the configuration of the slave station in one embodiment. The slave station 110 changes the power state of the power system 380 (1L or 2L) connected to the branch end 134 to PT300.
(PT146 or PT147) at voltage state, CT30
2 (CT142 or CT143) to detect the current state.

In the branch end data detection circuit 201, the abnormality of the power system is determined by the undervoltage relay 308, the ground fault overvoltage relay 3,
10 to determine the occurrence of an abnormality such as a ground fault or a short circuit. Then, the current state of the a-phase to the c-phase is detected by fetching the current data of one phase fetched from the CT 302 by the current fetch circuit 322 and the current data detected from the power system of the other phase (not shown). . These occur during a period (normally 50 to 60 milliseconds) from when an abnormality is detected to when the CB 304 is opened, and a power cycle (20 Hz at 50 Hz).
At least one cycle (millisecond), usually two to three cycles, is performed at a predetermined sampling cycle (for example, 1/12 cycle).

The transmission start circuit 312 receives a signal from the under-voltage relay (hereinafter referred to as 27 relay) 308 from the branch end data detection circuit 201 and a relay operation state (from the ground fault over-voltage relay (hereinafter referred to as 64 relay) 310). ON / OFF)
Are input, and a start signal for starting transmission when any of the relays indicates an abnormality and a voltage abnormal state signal (relay operation state) at that time are output.

The effective value calculating circuit 320 is a current taking circuit 32
2, the current data (instantaneous value) at the branch end is taken in, and the effective current value at the branch end is obtained from the data of at least one cycle of the system power supply after the occurrence of the accident. The AND circuit 314 receives an output from the transmission activation circuit 312 and a signal from the effective value calculation circuit 320 and outputs current state data and a relay operation state to the data transmission circuit 316. The data transmission circuit 316 transmits to the master station 112 a voltage abnormal state signal (relay operation state), an effective value of current data of each phase of the branch terminal, and zero-phase current data obtained therefrom. The zero-phase current data may not be transmitted, and may be calculated on the master station side.

FIG. 4 shows the configuration of the master station in one embodiment, and shows the detailed processing configuration of the orientation calculation in the master station 112. In the master station 112, the data receiving circuit 330 of the communication device 207 receives data from the slave station 110. In the master station 112, PT3 connected to the transmission line 390 of its own terminal
40 (PT144 / PT145)
The current state is detected at T346 (CT140 / CT141).

The under-voltage state detection circuit 332 and the ground fault over-voltage detection circuit 334 determine the contents of an accident (ground fault, short circuit, etc.) on the slave station side from the transmitted abnormal voltage data (relay operation state). The current receiving circuit 336 obtains the current state of the a-phase to the c-phase and the zero-phase current state of the slave station from the current data received from the slave station. Own-end data detection circuit 216
Detects an abnormality in the power system at the own end by the undervoltage relay 348 and the ground fault overvoltage relay 350 from the voltage state at the own end, and determines that an abnormality such as a ground fault or a short circuit has occurred in the power system at the own end. . The current take-in circuit 354 takes in current data of each phase at its own end in a period until the CB 342 is opened.

The accident point locating circuit 220 is provided with a simultaneous data determination circuit 224 for synchronizing data between the master station 112 and the slave station 110 at the time of correction calculation. The determination circuit 224 determines the reception timing of the abnormal voltage data at the branch end 134 by the undervoltage state detection circuit 332 and the ground fault overvoltage detection circuit 334, the undervoltage relay 348 at its own end 132,
By comparing the detection timing of abnormal voltage data at its own terminal from the ground fault overvoltage relay 350, the effects of transmission delay errors due to current sneaking around the branch end and transmission delay errors due to data transmission from slave stations are eliminated. .

That is, since the fault detection (detection of the abnormal voltage state) at the slave station and the master station for the same fault is performed simultaneously, the abnormal voltage data received first from the slave station 110 and the abnormal voltage data at its own end are detected. Are synchronized. Therefore, if the current state data following the abnormal voltage data is used, the current state data can be synchronized with its own current data. If the second and third data are received before the CB reclose time, those data are discarded. This ensures the data synchronization between the master station and slave stations. If no data is received from the slave station even after the CB reclose time elapses,
Abandon fetching branch end data.

More specifically, the simultaneous data determination circuit 224 determines the synchronism between the received data and the self-end data, and outputs a synchronizing signal during the reception period T2 of the abnormal voltage data received first and the current state data subsequent thereto. The synchronization signal and the current state data from the current receiving circuit 336 are taken into the AND circuit 225, and the current state data at the branch end is taken into the orientation calculation circuit 22.
Enter 2 In the orientation calculation circuit 222, the AND circuit 22
5, receive the synchronized branch-end current data via
Correction calculation of the fault point location is performed, and data indicating the fault location is output from the output circuit 360 to the outside.

FIG. 5 is a flowchart showing the procedure of the one-end type accident point locating operation according to one embodiment. In this system, a master station 112 and a slave station 110
At the same time, the following processing is started.

When the slave station 110 detects an abnormal voltage state of the transmission line at the branch end by using 27 relays or 64 relays (s1).
01), a branch end current for FL orientation is calculated from the sampling data for the system cycle (s102). For FL orientation, CT2 that matches with the other end from the effective value conversion and CT ratio
Indicates the calculation of the next value. Next, the operation (abnormal state) of the 27 relay or the 64 relay and the current calculation result are transmitted to the master station 112 (s103).

On the other hand, when the master station 112 detects the abnormal voltage state of the transmission line at its own end by using 27 relays or 64 relays (s104), a timer is started by the operation of the relay (s105). Next, the FL locating current is calculated (s
106) Based on the preset setting value of the branch current, a fault point locating operation is performed according to the fault content (ground fault / short circuit, etc.), and the result (b) is temporarily stored (s107). This result (b) is based on the conventional orientation calculation, and deals with a case where the slave station data cannot be obtained for some reason.

Next, it is checked whether or not the abnormal voltage data of the same accident as the own terminal has been received from the slave station (s108). If the abnormal voltage data has been received, the branch end current immediately after the abnormal voltage data is fetched and measured. The corrected accident point location calculation is performed (s109), and the result (a) is output (s110). On the other hand, when the abnormal voltage data is not received from the slave station side, it is determined whether or not the time measured by the timer has exceeded T3 (s11).
1) If the time does not exceed T3 from the abnormality detection, process s10
Return to 8. If T3 is exceeded, data reception from the slave station 110 is abandoned, and the stored result (b) is output (s).
112). T3 is the CB reclosing time T4 (normally 60 seconds)
It is set slightly shorter.

The effective value of the branch end current is calculated, for example, by calculating the effective value of one cycle after the occurrence of the accident from the instantaneous value of 12 samplings performed every 30 ° of the system power supply cycle (360 °). As a result, the data transmission capacity from the slave station can be reduced by 1 /
Can be compressed to 12.

The transmission data from the slave station to the master station includes a relay name indicating the operating state of 27 relays or 64 relays, state data (1/0), and an effective value of the branch end current following (or from the same frame). (Usually, 10 to 1000
(A)). Therefore, these digital data after the A / D conversion can be sufficiently transmitted through a telephone line (4W system) having a transmission speed of about 600 baud, and the system cost can be reduced.

FIG. 6 is a time chart showing the operation of the present system. In the system configuration shown in FIG. 1, when a ground fault occurs at the position F of the transmission line 101, the terminal 130
Then, from the voltage state of the branch terminal 134, each of the 64 relays for detecting a ground fault is activated (a, d), and the timer is started. The falling edge of the waveform (a, d) indicates the time when the CB is released. Next, before the release of the CB, the current data is taken in both the slave station and the master station (b, e),
On the master station side, the accident point locating device 220 is started immediately, and the locating operation is performed using the branch end data as the set value (f).

The slave station side starts transmitting branch end data (64 relays on, branch end current effective value) to the master station after T1 required for acquisition of branch end data and transmission procedure, and one set of data transmission time. The process ends after T2 (c). The master station 112
The reception of the branch end data is started substantially at T1, and the reception is ended substantially after T2 (g), and an accident point locating operation in which the branch end current is corrected with the actually measured value is performed.

If no data is received from the slave station by T3, the calculation result of (f) is substituted. Also, T3
If the received data has been received a plurality of times before, the first data is normal branch end data with synchronization, and the other data is discarded. The time T3 is slightly shorter than the CB re-closing time T4. During this period, the slave station transmits the branch end data only once and does not perform the re-transmission. The master station also takes in the data from the branch end only once during this period T3, and does not take in the data again. Then, when the fault location is started again at the master station after T4, the branch end data is fetched again to calculate the fault location.

[0045]

According to the present invention, a slave station is provided at a branch end to transmit a branch end current at the time of occurrence of an accident to the master station, and the master station simultaneously transmits the current with the own end current at the time of detection of an accident at the own end. The fault point locating calculation is performed using the current at the branch end and the current measured at the branch end, and the fault point locating calculation considering the sneak current to the branch end becomes possible. In addition, the accuracy of accident point location can be improved.

Further, since the branch end current transmitted from the slave station to the master station uses an effective value to compress the transmission data, the transmission path can be operated at a low speed and with a small number of communication lines. The use enables an inexpensive system configuration.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a power system to be protected according to an embodiment of the present invention.

FIG. 2 is a system configuration diagram of a one-end determination type accident point locating apparatus according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a slave station according to one embodiment.

FIG. 4 is a configuration diagram of a master station according to one embodiment.

FIG. 5 is a flowchart showing a procedure of a one-end accident point location calculation according to one embodiment.

FIG. 6 is a time chart showing the operation of the one-end determination type accident point location device.

FIG. 7 is a power transmission system diagram for explaining a conventional fault locating method for a transmission line having a branch line.

[Description of Signs] 101, 102: Transmission line, 103, 104: Branch line, 1
05, 106: power supply, 110: slave station, 112: master station, 1
14: dedicated line, 121 to 126: switch (CB), 13
0 ... Terminal (FL installation end), 132 ... Terminal, 134 ... Branch terminal, 140-143 ... CT, 144-147 ... PT,
201: branch end data detecting means, 203: modem, 20
5 communication device, 207 communication device, 209 modem, 2
11: current detection circuit, 212: communication abnormality detection device, 21
3: AND circuit, 214: branch end current circuits 214, 21
5: system abnormality detection circuit, 216: self-end data detection circuit,
220: one-end type fault locating device, 221: FL starting circuit, 222: fault locating calculation circuit, 223: correction calculating circuit, 300 ... PT, 302 ... CT, 304 ... CB, 30
8 Undervoltage relays 308 and 310 Ground fault overvoltage relay 312 Transmission start circuit 314 AND circuit 31
6 data transmission circuit, 320 effective value calculation circuit, 322
… Current take-up circuit, 332… undervoltage state detection circuit, 33
4: ground fault overvoltage detection circuit, 336: current receiving circuit, 34
0: PT, 342: switch, 346: CT, 348: undervoltage relay, 350: ground fault overvoltage relay, 354: current intake circuit, 360: output circuit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuto Ito 1-1-1, Kokubuncho, Hitachi City, Ibaraki Prefecture Inside the Kokubu Plant, Hitachi, Ltd. (72) Inventor Haruo Matsuoka 3-chome Nakanoshima, Kita-ku, Osaka-shi, Osaka No. 22 Kansai Electric Power Co., Inc. (72) Inventor Masanori Toshima 3-2-2 Nakanoshima, Kita-ku, Osaka-shi, Osaka-shi Kansai Electric Power Co., Inc. (72) Inventor Kiyoji Tanaka 3, Nakanoshima, Kita-ku, Osaka-shi, Osaka 3-22, Kansai Electric Power Co., Inc. (72) Takashi Obe 3-3-22, Nakanoshima, Kita-ku, Osaka-shi, Osaka Prefecture F-term within Kansai Electric Power Co., Inc. EF02 EF03 5G064 AA04 AC09 CB19 DA03

Claims (3)

[Claims] The present invention relates to an accident point estimating apparatus for determining one end of a transmission line having a branch line terminal, wherein an installation end side current detecting means is provided at a master station provided at an installation end side of the locating device of the multi-terminal transmission line. The end-side accident detection means and the accident point locating calculation means are provided with branch-end-side current detection means and branch-end-side accident detection means, respectively, at a slave station provided on the branch line terminal side. The master station captures the accident detection data by the installation end side accident detection means and the installation end current data by the installation end side current detection means, and the slave station accident detection data by the branch end accident detection means. −
The branch end current data is fetched by the branch end side current detecting means, and the fault detection data and the branch end current data are transmitted from the slave station to the master station. One end determination wherein synchronization is performed based on the detected data, and the fault point locating operation means performs fault point locating using the synchronized installation-end current data and branch-end current data. Type accident point rating device. 2. The one-side judgment type fault point rating device according to claim 1, wherein an undervoltage relay and a ground fault overvoltage relay are used as the branch end side fault detection means. 3. The branch end current data transmitted from the slave station to the master station according to claim 1 or 2, wherein an effective value is obtained from data taken in at least one power supply cycle after the occurrence of the accident. A one-end determination type accident point rating device for transmitting the effective value.