JPH04158274A - Method for detecting breakage of high voltage power distribution system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method for detecting disconnection in a high voltage power distribution system using a pole transformer and a communication network of the power distribution system.

B0 Summary of the Invention The present invention provides a slave station that detects the secondary voltage of the transformer for each pole-mounted single-phase transformer in a high-voltage three-phase distribution line and transmits a disconnection detection signal to the master station through the communication network of the distribution system. Based on this disconnection detection signal, the master station identifies the pole closest to the power supply among the transformer poles where a disconnection has been detected, and then sends information about the two phases to which the primary side of that pole-mounted transformer is connected. The primary side of the transformer is connected to the two phases included in the lower phases other than the above two phases near this transformer pillar, and the disconnected phase is identified from the information on the two phases of the transformer pillar where the disconnection has been detected, It is determined that a disconnection has occurred in the specified phase between the specified pillar and the pillar of the transformer connected to the two upper phases closest to the specified pillar.

C0 Conventional technology Insulated wiring for power distribution lines has progressed to almost 100%, contributing to increased safety. However, on the other hand, even if the wire breaks and falls to the ground, no ground fault current will flow, making it difficult to immediately locate the accident itself or the point of the accident.

For this reason, a disconnection detection protection relay has been proposed that uses a change in line current as information for detecting a disconnection in a distribution line on the power source side (substation).

D0 Problems to be Solved by the Invention However, in the disconnection detection protective relay that detects such line current changes, it is not possible to specify the disconnection section within a certain limited range (for example, between the transformer pillars).

The present invention was made in view of these problems, and its purpose is to address the possibility that the power distribution system will be improved in the near future to improve supply reliability and provide various services to consumers. The present invention relates to a disconnection detection method for a high-voltage power distribution system that can identify and detect a disconnection section between transformer pillars using a communication network with a large amount of power.

89 Means for Solving the Problems In order to achieve the above object, the present invention provides a disconnection detection method for a high-voltage power distribution system in which a disconnection detection method for a pole-mounted single-phase transformer connected to a high-voltage three-phase distribution line is provided with a A slave station is provided that detects the secondary voltage and transmits a disconnection detection signal to the master station through the communication network of the distribution system, and the master station transforms the transformer that detects the disconnection based on the disconnection detection signal transmitted from each slave station. Identify the first pole closest to the power supply among the transformer poles, and then identify the first two-phase information to which the primary side of the transformer on that pole is connected and the first two-phase information on the lower side closest to this transformer pole. The primary side of the transformer is connected to two phases including phases other than the second phase, and the disconnected phase is identified from the information on the second two phases of the transformer pillar where the disconnection is detected, and It is determined that a disconnection has occurred in the specific phase between it and the second pillar of the transformer which is connected to the first two phases and is higher than the first pillar and is closest.

F3 action When one phase of a high-voltage three-phase distribution line is disconnected, two
The primary voltage of the pole-mounted single-phase transformer connected to the phase is approximately 1/2
decreases to A slave station provided on the transformer pillar layer detects the secondary voltage of the transformer and transmits a disconnection detection signal to the master station via a communication network.

The master station can identify the first pillar in which a disconnection has been detected closest to the power source based on the disconnection detection signal transmitted from each slave station.

The disconnected phase is the information of the first two phases to which the primary side of the transformer of the identified first pillar is connected, and the two phases that include the lower phases other than the above two phases near this pillar. It can be identified as a common phase from the information on the second two phases of the transformer pole to which the primary side is connected and the disconnection has been detected.

In addition, the second pillar for determining the disconnection section is the identified first pillar and the nearest transformer pillar located above it, connected to the same first two phases, and in which no disconnection was detected. It can be specified as

G. Example Embodiments of the present invention will be described with reference to the drawings.

In Figure 1, 1 is a high-voltage three-phase distribution line, T8 to T13 are connected to the high-voltage distribution line 1, are pole-mounted transformers, and 28 to 2.3 are connected to the secondary sides of pole-mounted single-phase transformers T8 to TI3. The low voltage distribution lines (100-0-100V) B8 to B+3 are slave stations that detect the secondary side voltages of the pole transformers T8 to TI3 and send disconnection information to the master station via the communication network.

In Figure 2, A is the master station, N is the communication network, and B
n is a slave station, and voltage detector 11.n is a slave station. It is composed of a comparator 12, a disconnection detection section 13, and a signal transmission section 14. The master station or each slave station contains in advance data on which two of the three high-voltage phases (for example, the red phase and the own phase) the primary winding of each pole transformer is connected to. .

First, a wire breakage detection method will be explained with reference to FIG.

Each phase voltage Va, Vb, Vc, each line voltage Vab.

In the high voltage distribution line 1 of Vbc and Vca, when the a-phase line is disconnected, if there is no load L2 and the three phases are balanced, the line voltage is expressed as follows. Therefore, disconnection can generally be detected using the following algorithm using a voltage sensor.

However, vNoM is the line voltage during normal operation. ij is ab, be, ca Here, α is selected between 0.5 and 0.8.

By selecting this α, it is possible to detect a disconnection even if there is a load or L2 is unbalanced.

Accordingly, each slave station B8 to B+3 detects the secondary side voltage of the pole transformers T8 to TI3 using the above algorithm, detects a disconnection, and transmits a disconnection detection signal to the master station A through the communication network N.

Based on the disconnection detection signals transmitted from each slave station, the master station A uses a microcomputer or the like to identify the disconnection section using the following algorithm.

■ If there is even one pillar in which a disconnection is detected, processing is performed after at least one second has elapsed from that point.

■ Identify the pole with the highest power direction among the transformer poles where a disconnection was detected. In Figure 1, it is column 100.

As a result, candidates for two of the three phases that are disconnected are identified (red phase or self phase).

■ Next, check the phase of the transformer one level below the identified transformer pillar, and check whether one phase other than the two phases identified in (■) is detected. If the remaining one phase is included, the phase that is disconnected can be determined by whether or not it is disconnected. If the remaining one phase is not included, the process moves to the next lower transformer pillar and performs the same process. 11 in Figure 1
Column 0 is taken from the same two phases as column 100, so 1
The phase that is disconnected at column 20 is revealed. That is, the red phase can be detected as a broken phase. If column 120 is black,
If it is taken from the own phase, there is no voltage drop and disconnection cannot be detected, so it is clear that the red phase is disconnected.

■ Examine the transformer pillar one level above the transformer pillar where the first identified disconnection is detected, and see if the disconnected phase is included. If a disconnected phase is included, it can be seen that a disconnection has occurred between this transformer column and the first identified transformer column. If the disconnected phase is not included, move to the next higher transformer column and perform the same process. In FIG. 1, since column 90 does not include the red phase of the disconnection determined by ■, it can be seen that the disconnection has occurred in the red phase between column 80 and column 100.

H0 Effects of the Invention Since the present invention is configured as described above, it produces the following effects.

■ High-voltage distribution line break points can be identified between adjacent or several transformer poles apart. At the same time, a disconnected phase can also be determined.

■ Since a pole transformer is used to detect high voltage, a special high voltage instrument transformer is not required and the cost can be reduced.

■ Since the disconnection detection signal detected at each transformer pole of the high-voltage distribution line is used, there is no error in identifying the disconnection location.

[Brief explanation of the drawing]

Figures 1 and 2 relate to embodiments of the present invention; Figure 1 is a block circuit diagram showing connections between distribution lines, pole transformers, and slave stations, and Figure 2 is a block circuit diagram showing connections between distribution lines, pole transformers, and slave stations. FIG. 3 is a circuit diagram for explaining the principle of disconnection detection. l...High voltage 3-phase distribution line, 2s~213...Low voltage distribution line, Ta'''''TI3...Pole transformer, N...Communication network, A...Master station, B8~B11I+ Bn
... Slave station, 11... Voltage detector, 12... Comparator, 13... Failure detection section, 14... Signal transmission section. 1 other person

Claims (1)

[Claims] (1) A slave station that detects the secondary voltage of each pole of a pole-mounted single-phase transformer connected to a high-voltage three-phase distribution line and transmits a disconnection detection signal to the master station through the communication network of the distribution system. Based on the disconnection detection signals transmitted from each slave station, the master station identifies the first pole closest to the power source among the transformer poles in which a disconnection has been detected, and then uses the temporary A transformer whose primary side of the transformer is connected to two phases including information on the first two phases to which the side is connected and phases other than the first two phases located at a lower level near this transformer pillar, and a disconnection has been detected. The disconnected phase is identified from the information on the second two phases of the transformer pillar, and the second pillar of the transformer that is connected to the first pillar and the first two phases and is located above and closest to the first pillar is identified. A method for detecting disconnection in a high-voltage power distribution system, comprising determining that a disconnection has occurred in the specific phase between.