JPH0222575A - Direction decision type fault current passage display device - Google Patents

Abstract

PURPOSE:To accurately grasp the direction of accident currents of all power transmission lines by fitting coils and voltage detection rods to all electric wires one to one at an equal distance and detecting the voltage and current of almost each wire with the same gain. CONSTITUTION:The distances between the electric wires on a steel tower and coils, and the electric wires and detection rods are equalized. Zero-phase currents of the power transmis sion lines are extracted from induced voltages of the coils individually between a No.1 wire and a No.2 wire; and the zero-phase current of the No.1 wire is rectified synchronously with the its zero-phase voltage and the zero-phase current of the No.2 wire is rectified with its zero-phase voltage to obtain an output. The positive-phase currents of the power transmis sion lines are extracted from the induced voltages of the coils independently between the No.1 and No.2 wires and the positive-phase currents of the power transmission lines are extracted from currents flowing in the detection rods; and the positive-phase currents of the No.1 and No.2 wires are rectified synchronously with the positive-phase voltages respective ly to obtain two outputs. Further, the total of the absolute value of the current flowing in the detection rod of the No.1 wire and the absolute value of the current flowing in the detection rod of the No.2 wire is applied to a decision circuit to detect the no-voltage stages by the power transmission lines distinctively between the No.1 and No.2 wires. The decision circuit decides and displays the disconnection of >=1 power transmission line right after the passage of the accident current by using said outputs.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a device for determining and displaying the passage of fault current by attaching a coil and a voltage detection rod to the tower of a power transmission line. Effective when used in grounding systems or direct grounding systems.

<Prior art> In the past, there were devices that mainly detected the magnitude of fault current, but there was no device that could detect the direction of fault current separately for lines 1 and 2, and moreover, detect zero-sequence current and positive-sequence current. Problems to be Solved by the Invention In the conventional system, there is a power supply side and a load side, and in the case of a power transmission line where the neutral point on the power supply side is grounded, it worked conveniently, but if the power supply side is grounded at both ends. system or a directly grounded system, there is a drawback that fault current flows in from both ends, making it impossible to make a 9 judgment. Furthermore, in the case of a two-circuit power transmission line, if there is a large error when determining the sum of the currents of line 1 and line 2, there is a risk of malfunction.

<Means for Solving the Problems> In the present invention, the status of the power transmission line is accurately detected in all items. For this reason, coils and voltage detection rods are attached to all wires at equal distances, and the voltage and current of each wire are detected with equal gain, and variable resistors, filters, operational amplifiers, etc. are used to detect accurate zero-phase components. or take out the positive phase component.

Next, by synchronous rectification, the magnitude and direction of the positive phase component and zero phase component of lines 1 and 2 are detected separately, and the direction of the fault is detected, and at the same time, due to the fault in the transmission line.

Determine whether the circuit breaker has tripped.

Through these comprehensive judgments, it is possible to accurately determine the passage of fault current and the interruption situation at that time.

<Example> The figure is a diagram showing the mutual arrangement of a coil, a voltage detection rod, and an electric wire according to the present invention.

The distance between the wire 2 and the coil 14 is the distance between the wire 3 and the coil 15.
The distance between all coils and wires below is equal.

Similarly, voltage detection rods 8, 9, 10. II, 32. +3,!
: Soreso, t1 d corresponding electric 192.3, 4, 5.6
The distance between them is equal.

This is achieved in particular by the support 20.21 of the coil 15.
18 and voltage detection rod 9.12 were extended outside. However, without the supports 20 and 21, the coil 15 would not be able to sufficiently catch the magnetic flux of the electric wire 3, and the detection current of the rod 9 would also decrease. Electric wire 6 and coil 18. The same applies to the detection rod 12.

In this way, the current and voltage of all wires can be detected with approximately equal gain.

The subsequent signal processing can be done analog or digitally, and can be shown in a single circuit or block diagram, or in the form of a microcomputer program.

Since many types of transformations are possible in this way, the main text will explain the concept of technical processing.

(+) Find vector values of zero-sequence current and positive-sequence current for line 1 and line 2 separately.

(2) Find vector values of zero-sequence voltage and positive-sequence voltage for line 1 and line 2 separately.

(3) The vector value of the zero-sequence current of line 1 is synchronously rectified with the vector value of the zero-sequence voltage of line 1.

At this time, in the resistance grounding system, the resistance component of the zero-sequence current is detected, and in the direct grounding system, the component with a delay of about 45 degrees is detected.

In the same way, line 2 is synchronously rectified.

(4) Perform synchronous rectification using the vector value of the positive-sequence voltage that is the sum of the vector value of the positive-sequence current of line 1 and lines 1 and 2. Similarly, Line 2 is also synchronously rectified.

(5) If one or more of the absolute value of the positive sequence voltage of line 1 and the absolute value of the positive sequence voltage of line 2 becomes less than a certain value and this continues for more than Iθ seconds, the line It is assumed that the connection has been interrupted.

(6) For a certain period of time from the occurrence of the accident until the line is cut off, the synchronously rectified outputs of items (3) and (4) above are integrated and held to be used as the synchronous output during the accident.

(7) The synchronized output during the accident in item (6) above is input to the judgment circuit to determine the direction of the accident, and as a result, there is an accident in the direction that should be displayed, and the track is If it is determined that the system has been shut off, this will be displayed, and the synchronous output during the accident will be stored in memory and examined at a later date.

Depending on the case, it may be transmitted to a long distance using a T line, a FL line, an optical fiber cable, etc.

<Effects of the Invention> According to the present invention, it is possible not only to accurately know the direction of fault current in all power transmission lines, but also to display only the case where the circuit breaker breaks immediately after that, and to display the direction of fault current in other power transmission lines. It has the advantage of not displaying any fault current even if it flows.

[Brief explanation of the drawing]

The figure is a diagram showing the arrangement of a steel tower, electric wires, coils, and voltage detection rods for explaining the present invention in detail. The explanation of the symbols is as follows: l... Steel tower 2.3.4, 5, 6.7... Wire 8.9.10.1+, 12.13... Voltage detecting rod 14.1
5. +6.17.18.19...Coil 20.21...
・Support

Claims (8)

[Claims] (1) Coils and voltage detection rods should be placed on each transmission line tower wire. (2) All wires and coils should be placed at equal distances. (3) The distance between the electric wire and the voltage detection rod shall be the same. (4) From the voltage induced in the coil, extract the zero-sequence current of the transmission line separately for lines 1 and 2, synchronously rectify the zero-sequence current of line 1 with the zero-sequence voltage of line 1, and Synchronous rectification of zero-sequence current with zero-sequence voltage of line 2 to obtain respective outputs. (5) From the voltage induced in the coil, the positive sequence current of the power transmission line is calculated as 1
The positive-sequence voltage of the transmission line is extracted from the current flowing into the voltage detection rod, and the positive-sequence currents of lines 1 and 2 are synchronously rectified with the positive-sequence voltage, and the two lines are extracted separately. Getting the output. (6) Add the sum of the absolute values of the currents flowing into the voltage detection rods of Line 1 and the sum of the absolute values of the currents flowing into the voltage detection rods of Line 2 to the judgment circuit, and based on the judgment results, To detect the status of line 1 and line 2 separately and obtain the output. (7) Add the outputs of (4) and (5) above to the judgment circuit,
In addition, it shall have a determination circuit that comprehensively determines that one or more circuits of the power transmission line have been cut off immediately after the passage of the fault current, based on the output in item (6) above. (8) The display device is operated by the output of the determination circuit in item (7) above. Direction-discriminating type fault current passing indicator that uses the above (8) items at the same time