JPH0568333A - Fault section detection system for substation - Google Patents

Abstract

PURPOSE:To provide a fault section detection system for a substation by which one can know the fault division easily from outside in case that an accident occurs in the substation. CONSTITUTION:Buses 3, which are connected to the power receivers 1 and 2 of a substation, are divided into a plurality of divisions, A, B, and C, where a plurality of transformers 4, 5, and 6 are connected, by bus supporting insulators fitted with photoelectric current sensors 14. Since the direction of the accident current flowing to each photoelectric current sensor 14 changes by the division where an accident has occurred, the accident division can be judged by matrix method, by comparing the phase of each current wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fault section detection system for a substation that allows a fault section to be easily known from the outside when a fault occurs in the substation provided with a plurality of transformers. It is a thing.

[0002]

2. Description of the Related Art The basic equipment form of an unmanned substation is that two lines of power receiving units are connected to both ends of a single bus to receive one line or two lines, and a plurality of transformers are simultaneously installed on these buses. It is common for them to be connected and each transformer to carry multiple loads. Since a current transformer is installed on the line side of the power receiving unit, if a failure occurs, whether it is an internal failure or an external failure of the substation depends on the operating condition of the current transformer of the power receiving unit and can be sent from a remote control station. I can know. However, if an internal failure occurs in the bus section of the substation, the failure section cannot be known from the outside, and all the transformers are stopped until the worker goes to the site and finds the failure location. There is no choice but to do so, and there is a drawback that power outages are large and take a long time.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and when an internal failure occurs in a substation, the failure section can be easily known from a distant control station or the like. It has been completed to provide a failure section detection system for a substation that can immediately re-transmit power in a healthy section by disconnecting the failure section.

[0004]

SUMMARY OF THE INVENTION The present invention, which has been made to solve the above problems, provides a plurality of transformers in which a busbar connected to a power receiving section is connected by a busbar support insulator with a photocurrent sensor. It is characterized in that it is divided into sections, and the section in which a failure occurs is determined by a matrix method by comparing the phases of the respective current waveforms obtained by the photocurrent sensor attached to the busbar insulator. is there.

[0005]

According to the present invention, when an internal fault such as a ground fault or a short circuit occurs in a substation, a fault current flows toward the fault point, and a photocurrent attached to the busbar support insulator at the boundary of each section. Since the output of the sensor fluctuates, by comparing the phases of the current waveforms detected by the photocurrent sensor, it is possible to know in which section the failure has occurred from a remote location. Therefore, by disconnecting the faulty section by remote control and immediately restarting power transmission to the healthy section, the power outage time and the power outage section can be minimized.

[0006]

The present invention will now be described in more detail with reference to the illustrated embodiments. FIG. 1 is a plan view showing a facility configuration of a typical unmanned distribution substation. 1, 2 are first and second power receiving units, 3 is a busbar unit, 4, 5 and 6 are first and second units. , The third transformer. The bus bar 3 is provided with three lead wires 3a, 3b, 3c corresponding to each phase of the three-phase alternating current.
For 3a, 3b, 3c, three transformers 4, 5,
6 are connected to each other. Then, the power is normally received in one of the power receiving units 1 and 2, and is supplied to the three transformers 4, 5 and 6 via the lead wires 3a, 3b and 3c, and each transformer receives its own load. The power is distributed to the side.

A disconnector 7, a current transformer 8, and a circuit breaker 9 are provided in the power receiving units 1 and 2, respectively, and the current transformer 8 causes a fault current to flow in the event of a ground fault or a short circuit in the substation. Can be detected. On the other hand, the busbar section 3
Each of the lead wires 3a, 3b, 3c is divided into three sections A, B, C by bus line disconnectors 12, 13, but in the present invention, the support insulators of these bus line disconnectors 12, 13 are shown in FIG. The photocurrent sensor 14 shown in FIG. 2 is provided.

That is, in FIG. 2, reference numeral 15 is a busbar support insulator for supporting the busbar disconnector 12, 12a is a blade of the disconnector, 12b is a contactor, and 12c is a terminal plate. Around the terminal plate 12c, a donut-shaped iron core 14a and a sensor element
14b and a photocurrent sensor 14 are attached, and the current flowing through the bus bar is taken out as an optical signal. It is preferable to use a Faraday element such as YIG or BSO as the sensor element 14b, and an optical signal is taken out to the outside through an optical fiber 16 built in the busbar support insulator 15. Reference numerals 17 and 18 denote a moisture-proof pipe and a moisture-proof container provided above and below the busbar support insulator 15 to prevent insulation deterioration of the optical fiber 16 part. The support insulator to which the photocurrent sensor is attached may be attached to a position different from the disconnector.

As shown in FIG. 3, a light emitting element 19 and a light receiving element 20 are connected to the photocurrent sensor 14, and the outputs of these elements are amplified and then the phase comparison ratio differential detector 21 of the failure section discriminating apparatus 21. Is input to the failure section discriminator 22. Then, together with the signals from the current transformers 8 of the power receiving units 1 and 2, the fault section is discriminated by phase comparison of the fault currents. This determination is performed by the matrix method, and its specific content is as described below.

FIG. 4 is a diagram for explaining a matrix type accident section discrimination method by phase comparison of the present invention. For convenience of explanation, the photocurrent sensor 14 between the section A and the section B is set to 14P and the section B is set. The photocurrent sensor 14 between section C and section C is designated as 14Q. Then, as shown in the upper part of FIG. 4, when the direction of the fault current changes to the right and left, the output of the photocurrent sensor 14 changes to − and +.

If a ground fault or the like occurs at point F _{1 of} section B, a current flows rightward to the busbar of the portion where the photocurrent sensor 14P is attached, so that its output i ₁ becomes negative and vice versa. Since a current flows leftward in the bus bar where the photocurrent sensor 14Q is attached, the output i ₂ becomes +.
Therefore, the phases of the outputs of both photocurrent sensors 14P and Q are shown in FIG.
As shown in the diagram on the left in the lower part of the figure, it faces in the opposite direction.
Determines that the faulty section is B.

Next, when a ground fault or the like occurs at the point F _{2 of the} section A, a current flows leftward to the busbar of the portion where the photocurrent sensor 14P is attached, so that the output i ₁ becomes +, Further, since a current also flows leftward to the bus bar where the photocurrent sensor 14Q is attached, its output i ₂ also becomes +.
Therefore, the phases of the outputs of both photocurrent sensors 14P and Q are shown in FIG.
As shown in the center diagram in the lower part of the figure, the same direction is oriented in the first quadrant of the X-R coordinate, and this is detected by the phase comparison ratio differential detector 21 and the failure section discriminator 22 determines the failure section as A. ..

When a ground fault or the like occurs at the point F _{3 in the} section C, the output phases of the photocurrent sensors 14P and 14Q are X-R as shown in the lower right diagram of FIG. 4 contrary to the above. In the third quadrant of the coordinates, they are oriented in the same direction, which is detected by the phase comparison ratio differential detector 21 and the failure section discriminator 22 judges the failure section as C. Table 1 summarizes the above contents. In any case, it is needless to say that it is possible to discriminate between the internal accident and the external accident of the substation by the direction of the accident current flowing through the current transformer 8 of the power receiving units 1 and 2.

[0014]

[Table 1]

When the failure section is determined to be A as described above, the failure section is separated by opening the bus line disconnector 12, and if the second power receiving section 2 receives the power, a healthy section is obtained. It is possible to immediately restart the power distribution to the sections B and C. When a failure occurs in section B, the busbar disconnectors 12 and 13 are both opened to separate the failure section, and both the first and second power receiving units 1 and 2 are separated.
By receiving the power in section A, it is possible to immediately restart power distribution to sections A and C, which are healthy sections. Further, when a failure occurs in section C, the failure section can be separated by opening the busbar disconnector 13 between B and C, and power distribution to sections A and B, which are sound sections, can be resumed immediately.

[0016]

As is apparent from the above description, the present invention utilizes the photocurrent sensor attached to the busbar insulator when a failure occurs inside a distribution substation having a plurality of transformers. Since the faulty section can be immediately identified by the matrix method by phase comparison, the faulty section is separated and the power is transmitted to the sound section automatically or in a short time by a command from a remote control station. Can be implemented. Therefore, the power outage time and the power outage area can be minimized, and it is also effective in performing the restoration work promptly. Moreover, in the present invention, since the photocurrent sensor is attached to the busbar insulator, no extra space is required, and it can be easily attached to an unmanned substation or the like which has a small space. Since it is difficult to pick up noise due to the electric field and magnetic field of the above, it is possible to construct an extremely reliable system. Therefore, the present invention, as a faulty section detection system for a substation that eliminates the conventional problems, is extremely important in contributing to the development of industry.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing how the photocurrent sensor is attached to the busbar support insulator used in the present invention.

FIG. 3 is a block diagram of the entire system.

4A and 4B are a circuit diagram and an output waveform diagram of a photocurrent sensor for explaining a matrix type fault section determination method by phase comparison of the present invention.

[Explanation of symbols]

 1 Power receiving part 2 Power receiving part 3 Bus bar 4 Transformer 5 Transformer 6 Transformer 14 Photocurrent sensor 15 Bus bar support insulator 21 Phase comparison ratio Differential detector 22 Fault zone discriminator

Claims (1)

[Claims] 1. Buses 3a, 3b connected to the power receiving units 1, 2,
3c is divided into a plurality of sections A, B and C to which a plurality of transformers 4, 5 and 6 are connected by a bus bar insulator 15 with a photocurrent sensor 14, and the section in which the failure occurs is the bus bar insulator. 15
A fault section detection system for a substation, characterized by making a matrix-based determination by comparing the phases of respective current waveforms obtained by the photocurrent sensor 14 attached to the.