JP2690927B2 - Protection relay system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a protective relay system for a power system, and in particular, determines the presence / absence of an accident in a protected section based on information from a plurality of slave stations. The present invention relates to a backup system in a protection relay system when information from a specific slave station cannot be obtained.

[Conventional technology]

The protective relay system of the electric power system is shown in Fig. 2 reproduced from Fig. 2.2 on page 19 of the Institute of Electrical Engineers of Japan lecture "Protective relay engineering". The presence or absence is judged. A method that determines the presence or absence of an accident from these information at one end of the protection section (distance relay method, etc.) and a method that determines the presence or absence of an accident by combining the information from each end of the protection section (differential relay) Method), but the latter is often used for main protection.

[Problems to be solved by the invention]

Since the latter method uses the information of multiple ends to make a determination, it is generally possible to make a more accurate determination than the former, but even if one of the multiple ends lacks information, it will not be possible to make a determination, or even if it can be done There is a drawback that the determination accuracy is reduced.

Further, in the case of the conventional protective relay device, since the information input device for the determination is fixedly assigned, there is no way to reject the determination result at that time when the information is missing. .

Therefore, if a failure occurs in either the sensor that detects accident information or the transmission path and the information on the input device side is lost, it is difficult to determine the accident, or there is a problem that the reliability is significantly impaired. there were.

An object of the present invention is to provide a highly reliable protective relay system that does not have the above problems.

[Means for solving the problem]

The above object can be achieved by using information from another input device outside the protection section on the input device side where the information is missing, instead of the information of the input device where the information is missing.

[Action]

For example, when the protection relay 14 in FIG. 1 is a current differential relay and the current information at the A end is missing, the current information at the A end is obtained from the current information at the transmission line connected to the A end side of the protection section. By determining, it is possible to determine the presence or absence of an accident in the protected area.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to FIG.

Switchgear 2,3 that separates the track from both sides of the protection section 1.
And sensors 4 and 5 for obtaining accident information such as current and voltage.
Consider the system in which is installed. In this case, the protection section 1 has two terminals for the sake of simplification, but this embodiment is valid even if it has three or more terminals. Now, the left end of the protection section in the figure is called the A end and the right end is called the B end. Furthermore, it is assumed that both ends are in contact with another system, and that there is a branch line on the A end side and there are C and D ends. Opening devices 6, 7 and sensors 8, 9 similar to the A and B ends are provided at both C and D ends.

Further, communication slave stations 10 to 13 for collecting information of each sensor and switching information of the switchgear are provided at each end, and are connected to the protective relay device 14 constituting the master station via a transmission line. There is.
That is, the slave stations 10 to 13 are input devices to the protective relay device 14. The configuration of the slave station is shown in FIG. In this figure, for the sake of clarity, each slave station is provided with a function of integrating the information of the switchgear and the sensor, but it goes without saying that they can be transmitted individually. Also, for example, C
There may be a case where the information of the end and the information of the D end are integrated, but it is omitted here.

The protective relay device 14 is usually a slave station at both ends of the protection section 1.
The difference current is calculated on the basis of the information from 10, 11, and the presence or absence of an accident in the protection zone 1 is judged by this magnitude. If the difference current is larger than a predetermined threshold value, it is judged as an accident and A
A device having a function of issuing an opening command to the switching devices 2 and 3 at both ends of B through the slave stations 10 and 11. Furthermore, since the protection relay device 14 which is the master station is also connected to the C-terminal and D-terminal slave stations 12 and 13 outside the protection section 1 through a transmission line, the slave station 1
You can also enter information from 2,13. As long as the information from the slave stations 10 and 11 at the A and B ends is normal, the information from the slave stations 12 and 13 is not used for protection of the protection section 1, but the current information at the A end cannot be obtained. When such a failure occurs, the current value from the slave stations 12 and 13 at both ends of C and D in the section adjacent to the A end is input, and the sum is calculated to obtain the current at the A end. The presence or absence of can be determined. However, in this case, unless there is information that there is no accident in the adjacent section surrounded by each end of A, C and D, it does not make sense to separate only the protection section 1, so the opening command from the protective relay device 14 is B・ C ・
It is emitted to both ends of D and opens the switchgear 3,6,7.

Although it is assumed that the A-side information is missing in the above-described embodiment, although not shown when the B-side information is missing, it is self-evident that the accident determination can be performed similarly based on the information of the B-side adjacent section.

Further, in the above embodiment, the slave stations 10 to 13 were provided with only the information collection / distribution and communication function, but as shown in another embodiment of FIG. 4, the slave station itself should be provided with the protective relay function. You can Fig. 5 shows the configuration of the slave station.

The slave station 40 inputs the current information of the sensors 34, 35, 38, 39 to the slave station of FIG. 5, converts it into a digital value with an A / D converter,
Normally, the internal current of the protection section 31 is judged by calculating the difference current between the A and B ends with the arithmetic processing circuit CPU, and the switchgear 3
Issue a release command to 2,33. However, once the information at either end of A or B fails, the information at both ends of C or D is input, and after determining the presence or absence of an accident, an opening command is also issued to the switchgear 33, 36, 37. According to this embodiment, there is an effect that the distributed processing of the relay function is enabled and the determination with higher reliability can be performed.

〔The invention's effect〕

According to the present invention, since the conventional input device is fixedly assigned to the protective relay device, it is impossible to determine the accident if any information of the input device is lost. On the other hand, there is an effect that it is possible to determine an accident by using the information of another input device provided outside the protection section of the input where the failure has occurred.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a diagram of a conventional protective relay system, and FIG. 3 is a diagram of a slave station shown in FIG. FIG. 4 is a block diagram of another embodiment.
FIG. 5 is a block diagram of the slave station of FIG. 1 …… Protection section, 2,3,6,7 …… Switching device, 4,5,8,9 …… Sensor, 10 to 13 …… Communication slave station, 14 …… Protective relay device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Terunobu Miyazaki 1-1-1, Kokubun-cho, Hitachi-shi, Ibaraki Inside the Kokubun factory of Hitachi, Ltd. (56) Reference JP-A-59-72925 (JP, A)

Claims (1)

(57) [Claims] 1. A sensor provided at each end of a protection section of a power system for detecting an accident occurring in the protection section, and a switch for disconnecting this section from the power system when an accident occurs in the protection section. A device, a slave station that transmits the information of the sensor and the switching information of the switchgear, and a protective relay device that determines an accident in a protection section based on the transmitted information and issues an opening command to a predetermined slave station. In a protective relay system including, a slave station in a section adjacent to the protection section, and a transmission line connecting the slave station and the protection relay device, the protection relay device in the protection section Protective relay of a power system, which is characterized in that when at least one of information missing or error in information from a slave station is detected, an accident determination is performed using information from a slave station in an adjacent section. system.