JP2536932B2 - Out-of-phase ground fault detection method - Google Patents

Description

The present invention relates to a different-phase ground fault detection method capable of detecting ground fault accidents simultaneously occurring in different distribution lines.

[Conventional technology]

FIG. 5 (A) is a system configuration diagram showing a conventional out-of-phase ground fault detection method. In the figure, 1 is a busbar in a power distribution system, 21 and 22 are distribution lines connected to the busbar 1, 3 is a distribution transformer, and 41 and 42 are circuit breakers that interrupt the distribution of power to the distribution lines 21 and 22, respectively. (Hereinafter referred to as CB), 5
1,52 are zero-phase current transformers (hereinafter referred to as ZCT) installed on distribution lines 21,22.
Say. ), 61 and 62 are ground fault direction relays operated by the zero phase current output from these ZCTs 51 and 52, 7 is a ground fault overvoltage relay operated by zero phase voltage, and 8 is a connecting transformer.

Next, the operation will be described. When a ground fault occurs in any section of the distribution lines 21 and 22, the ground fault direction relays 61 and 62 are activated by the zero-phase current extracted by the ZCTs 51 and 52. The operation of the ground fault direction relays 61, 62 cuts off the corresponding CBs 41, 42. Also, in general,
For the purpose of fail-safe, not only the ground fault direction relays 61 and 62 but also the ground fault overvoltage relay 7 that operates by zero-phase voltage is used as a sequence to cut off the CB41 and 42, and both relays operate at the same time. Cut off CB41, 42.

That is, in the distribution substation, the breaking conditions of the breakers 41 and 42 are determined by the logical configuration as shown in FIG. 5 (B). In the figure, 15a and 15b represent AND circuits. In other words, the ground fault direction relays 61 and 62 are operating, and
When the ground fault overvoltage relay 7 operates, the CB41, 42 are cut off.

[Problems to be Solved by the Invention]

Since the conventional out-of-phase ground fault detection method is configured as described above, when a ground fault accident occurs in different sections of the same distribution line 21 and 22, it cannot be detected that it has occurred in two places, For example, even if the accident disappears in the F1 section after simultaneous occurrence in the F1 and F2 sections (section 12 and section 13) shown in FIG. 5 (A), the ground fault accident in the F2 section causes the There was a problem that the breaker 41 was cut off. In addition, a section of a certain distribution line 21, 22 and another distribution line 21,
If there is a ground fault at the same time in a section with 22,
Depending on the resistance of the accident point, one of the ground fault direction relays 61, 62 does not satisfy the operating condition, and there is a possibility that the ground fault may not be detected due to non-operation.

The present invention has been made to solve the above problems, and even if a ground fault accident occurs in different sections of the same distribution line at the same time, it is possible to detect all the sections where the accident has occurred, and to extend over multiple distribution lines. It is an object of the present invention to provide a different phase ground fault detection method that can reliably detect a fault occurrence section even if ground fault accidents occur simultaneously in different sections.

[Means for solving the problem]

The out-of-phase ground fault detection method according to the present invention provides a slave station connected to a distribution line in each section of a plurality of distribution lines, and each slave station has a zero-phase current and a zero-phase overcurrent relay that responds to a voltage and a ground. A relay relay is provided, and response signals created by each slave station according to the operating status of these relays are collected via transmission means,
It is provided with a master station that specifies an accident occurrence section based on the state mismatch of the zero-phase overcurrent relay and the ground fault direction relay between the slave stations corresponding to each of the adjacent sections.

[Action]

The slave station according to the present invention transmits the operating status of each relay provided in the slave station to the master station as a response signal with a slave station address. On the other hand, the master station performs a predetermined logical operation based on the slave station address and the operation status of the relay included in the received response signal to specify the accident occurrence section.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which the distribution line has two lines. In the figure, 511 to 514 and 521 to 524 are the slave stations 911 to 914 and 921, respectively.
~ Zero-phase current transformer ZCT that supplies zero-phase current to ~ 924, 611 ~ 614, 6
21 to 624 are ground fault direction relays provided in the respective slave stations 911 to 914,921 to 924, and 711 to 714,721 to 724 are zero-phase overcurrent relays provided in the respective slave stations 911 to 914,921 to 924, 1
11-114, 121-124 are each slave station 911-914, 921-924
Corresponding to the communication line (transmission means) 13 and each slave station 91.
A communication box for connecting 1 to 914 and 921 to 924, and a master station 14 connected to a communication line 13. Others are the same as those shown in FIG. 5 (A) with the same reference numerals.

Next, the operation will be described. If a ground fault occurs in any of the sections, the corresponding slave stations 911 to 914,921 ...
At 924, ground fault direction relays 611-614, 621-624 or zero-phase overcurrent relays 711-714,721-724 are activated. Therefore, the corresponding slave station creates a response signal indicating that the relay has operated, and further adds the slave station number of its own station to the corresponding communication box 111-114, 121-124 and communication line 13
To the master station 14 via. The master station 14 receives this response signal and cuts off the corresponding cutoffs 41 and 42 based on the added slave station address, and the other slave stations 911 to
Response signals are also collected from 914, 921 to 924.

Here, section 12, section 13 and section 22 (hereinafter, F1, F2
And called F3. The operation of the master station 14 will be described by taking as an example a case where a ground fault accident occurs at one or two of the above). The zero-phase overcurrent relays 711 to 714 and 721 to 724 are activated when the zero-phase current exceeds a certain value. Here, the constant value is not a value that flows at the time of a normal one-line or two-line ground fault accident, but is a value that operates in the case of a different point and different phase ground fault. In addition, the ground fault direction relays 611 to 614,6
Reference numerals 21 to 624 are for reacting when the zero-phase current enters a predetermined phase range with reference to the zero-phase voltage. Therefore, the response signals collected by the master station 14 when a ground fault occurs in each section of F1 to F3 are as shown in FIG. In Fig. 2, the left column shows the section where the ground fault occurred by F1, F2, and F3, and "○" or "X" indicates each slave station 911 to 914, 9 at that time.
The operation status of the relays 21 to 924 is shown. “O” indicates that the relay is operating, “x” indicates that the relay is not operating, and “−” indicates that the operation is indefinite. Referring to FIG. 2, adjacent child stations 911-914,921-
Zero-phase overcurrent relays (denoted as 51GH in Fig. 2) 711 to 714, 721 to 724 between 924 or ground fault direction relays (denoted as 67G in Fig. 2) 611 to 614, 621 to 624 are not matched. If it can be detected, the ground fault accident occurrence section can be specified. SG1, SG2 or SG3 from the enclosed state respectively
It indicates that the ground fault in the section of F1, F2 or F3 can be detected.

FIG. 3 is a diagram showing a circuit configuration example of a circuit in the master station 14 for specifying the ground fault accident occurrence section from the collected data as shown in FIG. In FIG. 3, only the portion for specifying the section from F1 to F3 is shown. In the figure, 14a to 14f are exclusive OR circuits, and 14g to 14i are logical OR circuits. Note that the slave station's zero-phase overcurrent relay 712 with the reference numeral 912 is 51GH12, and the ground fault direction relay 612 is 67GH.
Shown as G12. Then, the response signal for each relay becomes 0 corresponding to "1" and "x" corresponding to "○" in FIG.
Input to a to 14f. For example, if a ground fault occurs in the sections F1 and F3, from Figure 2, 51GH11,51GH12,
You can see that 51GH21 and 51GH22 work. Therefore,
Only the two exclusive OR circuits 14a and 14e output "1", and only the two OR circuits 14g and 14i output "1". Therefore, it can be seen that a ground fault occurred in the sections F1 and F3.

FIG. 4 is a flow chart showing a process of specifying the ground fault accident occurrence section when the master station 14 is configured by a computer.
To explain the operation, first, in step ST1, the communication line 1
Response signals are collected from each slave station 911 to 914, 921, 924 via 3. Then, the operating statuses of 51 GH and 67 G of the slave stations 911 to 914 and 921 to 924 are sequentially stored in the first register and the second register (steps ST2 to ST17). When the storage is completed (step ST17), the contents of the first register and the second register are as shown in FIG. 2 with the 51GH state of the slave station 11 with the reference numeral 911 as the least significant bit (bo). (See the bottom of FIG. 2). Here, "○" in FIG.
Corresponds to "1" and "x" corresponds to "0".

Next, in order to compare the relay states of the adjacent slave stations 911 to 914 and 921 to 924, the contents of the second register for 2 bits,
After shifting to the lower bit side (step ST18), the contents of the two registers are exclusive-ORed bit by bit (step ST19). As a result of exclusive OR, adjacent child stations 911 to 91
Since the non-matching state of the relay states of 4,921 to 924 is obtained as "1", the ground fault occurrence section can be specified by checking whether the corresponding bit of the obtained result is "1" (steps ST20 to ST25). ).

〔The invention's effect〕

As described above, according to the present invention, the out-of-phase ground fault detection method is used, in each section of a plurality of distribution lines, a slave station having a zero-phase overcurrent relay and a ground fault direction relay is provided, and each slave station has a relay The master station that collects the operation status performs logical operation based on the response signal of the adjacent slave station to identify the ground fault accident occurrence section, so it is possible to detect the ground fault accident in multiple sections in the same distribution line. There is an effect that it is possible to obtain a method capable of detecting the ground fault accidents occurring in a plurality of sections over different distribution lines without fail.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an out-of-phase ground fault detection method according to an embodiment of the present invention, FIG. 2 is an explanatory diagram for explaining a relay operation state of each slave station, and FIG. 3 is a ground fault in a master station. FIG. 4 is a flow chart showing the operation of the master station for specifying the ground fault accident occurrence section, and FIG. 5 (A) shows the conventional out-of-phase ground fault detection method. The system configuration diagram, FIG. 5 (B), is a circuit diagram showing the logical conditions for interrupting the conventional circuit breaker. 1 is a busbar, 21 and 22 are distribution lines, 41 and 42 are circuit breakers, 511 to 51
4,521 to 524 are zero-phase current transformers ZCT, 611 to 614,621 to 624 are ground fault direction relays, 711 to 714,721 to 724 are zero phase overcurrent relays, 9
11 to 914, 921 to 924 are slave stations, 13 is a communication line (transmission means), 14
Is the parent station. In the drawings, the same reference numerals indicate the same or corresponding parts.

Front page continuation (72) Inventor Kenji Kamiwaki 2-47 Shiobara, Minami-ku, Fukuoka City, Fukuoka Prefecture, Kyushu Electric Power Co., Inc. Research Institute, Electric Power Laboratory (72) Inventor Toshinori Ebisaka Wadazaki, Hyogo-ku, Kobe-shi, Hyogo Prefecture 1-2, Machi Mitsubishi Electric Co., Ltd. Control Works (72) Inventor Keiji Isahaya 1-2-1, Wadazakicho, Hyogo-ku, Kobe Hyogo Prefecture Mitsubishi Electric Co., Ltd. (72) Inventor Akira Kaneda 1-2-1 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Inside Mitsubishi Electric Corporation Control Works (56) Reference JP 61-15522 (JP, A) JP 57-83119 (JP, A)

Claims (1)

(57) [Claims] 1. A plurality of distribution lines that are connected to a bus bar and are divided into a plurality of sections, respectively, and are provided between the bus bar and the plurality of distribution lines, and are generated in any of the plurality of sections. In a power distribution system including a circuit breaker that is cut off by the ground fault, the zero phase overcurrent relay has a zero phase overcurrent relay and a ground fault direction relay that respond to the zero phase current and voltage in each section. And a plurality of slave stations that output a response signal indicating the operation status of the ground fault direction relay,
Between the transmission means for transmitting the response signal output from each of the slave stations, and between the slave stations corresponding to each of the adjacent sections, based on the response signals, by receiving the response signal via the transmission means. Of the zero-phase overcurrent relay and the ground fault direction relay are detected, and a section surrounded by the slave stations in which the state mismatch is detected is specified as a ground fault accident occurrence section, and a master station is provided. Out-of-phase ground fault detection method.