JPS59222028A - Method of detecting flash trouble in transmission line branch point - 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 This invention relates to a method for detecting flash faults at power transmission line branch points.

(B) Conventional technology and its problems When a power transmission tower or transmission line is struck by lightning, the insulator is destroyed by flash or reverse flash, and the current being transmitted flows into the ground through the discharge path of the accident tower. occurs, and this follow-on current activates the relay, resulting in a power outage. Therefore, it is necessary to promptly detect the lines and towers involved in the flash fault and to carry out accident recovery.

In order to solve this problem, the present applicant has proposed
No. 22 describes a method and device for detecting flash-faulted steel towers, Japanese Patent Application Laid-Open No. 57-901-71 describes a follow-up detection device, and Japanese Patent Application Laid-Open No. 57-90172 describes the use of the above-mentioned detection device. We propose a detection method that eliminates false detections.

The detection method according to Japanese Patent Application Laid-open No. 57-46622 is based on the detection method on both sides of the overhead ground wire 2 centered on the tower 1, as shown in Figure 1, or on the top of the tower 1 and close to the ground as shown in Figure 2. A C-F (current transformer) 3 is attached to the section, and when a flash fault occurs, the follow-on current flowing to the tower or ground wire is detected by two Cr2.3, and the secondary current phase of each detected CT is By comparing the two, it is determined that if the phases match, it is a non-accidental tower, and if they do not match (transmission phase), it is determined to be an accidental tower.

On the other hand, the invention disclosed in JP-A No. 57-90172 sets the magnetic saturation level of the core of the CT low to output a secondary current as a pulse corresponding to the zero cross point of the following current, and converts it into a light beam. The method of JP-A No. 57-901.71 eliminates the difference in the generation timing of the pulse output when a follow-on current occurs and In order to prevent misclassification by the sorting device based on the DC component superimposed on the following current, at least the first pulse is excluded and the second or third pulse is used for phase difference comparison. It is.

However, the above method is aimed at detecting flash faults on general transmission towers as shown in Figure 1, and is not intended for detecting flash fault areas at transmission line branch points. There wasn't. In other words, in the above method, if two CTs are used or if there are two or more power transmission lines, it is not possible to clearly identify where the flash fault occurred by simply comparing the phase difference between the two CRs. cannot be determined.

V→ Means for Solving the Problem This invention provides a method for detecting flash faults at transmission line branch points.
A flash fault current detecting C1' is installed on each overhead ground wire of the branch tower, and by mutually comparing the phase of the secondary current flowing through each CT, it is possible to identify the flash fault line, and the current phase of each CT is matched. In such a case, the signal from the A N +) gate circuit connected to the output circuit of each current transformer and the signal from the current phase comparator circuit of each current transformer should be compared to determine that it is a branch tower flash fault. I have to.

Hereinafter, the present invention will be explained in detail based on the attached FIGS. 3 and 4.

Reference numeral 10 in Fig. 3 indicates a branch tower, and in the vicinity of this tower, CT14, CT15.
Install 6. In addition, if each CT is based on the tower side and installed in a direction that provides a positive output when fault current flows from the branch tower 10 to the track side, the circuit configuration of the follow-on current detection device and phase comparison circuit will be simplified. . Therefore, the following explanation will be based on this method.

In the above CT14, 15.16, as shown in the $4 figure,
Circuits 17, 18, and 19 that mutually compare the phases of secondary currents converted into optical pulses, etc. are connected, and the signals of each phase comparison circuit are compared to determine in which line a flash fault has occurred. . For example, if there is a flash fault on the line (I), the fault current flowing through the overhead ground wires 11, 12, 13 will be in the direction shown by the solid line arrow in FIG. Therefore, as shown in case 1 in the table below, the signals A and C from the phase comparator circuits 17 and 19 become different phase determination signals (with output), and the signal B from the circuit 18
becomes a signal O (no output) for in-phase determination.

Therefore, from the presence or absence of this signal, it is possible to know which line the flash fault occurred on.

However, if there is a flash fault in the branch tower 10, the direction of the fault current will be as shown by the dotted line in Figure 3, and in this case, the signals A and B will be activated as shown in Case 4 in the table below.

Since the same phase judgment signal for both C and C is 0, it is considered that there is no accident. Therefore, an AND gate circuit 20 is added to the output section of c-r 14, 15, and 16 to detect that each C1' is activated (a large current flows), and that signal is used to output the other A, B, and C. If the signal is 0, it is determined that it is a branch tower flash fault.

Judgment Table Note that the number of CTs used will increase as the number of branch lines on branch towers increases, but the basic concept of detection is the same as above in that case.

2) Effects As explained above, this invention identifies lines with flash faults by mutually comparing the phases of the secondary currents of CTs attached to each overhead ground wire of branch towers, and furthermore, detects flash faults on branch towers. If there is a fault, it is detected by illuminating the output signal of the ANI gate circuit and the phase comparison rotation signal of each Ci'', thereby reducing flash faults at transmission line junctions. It can be detected accurately and accurately.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing the conventional flash fault detection method, and Figure 3 is the overhead ground wire c'-i' of the present invention.
FIG. 4 is a block diagram showing a circuit for phase comparison. 10... Branch tower, (i,), (IT), (
Trr)...Power transmission line, 11.12.13...Overhead ground wire, 14,15.16...C-1'', 17,18.1
9. Phase comparator circuit, 20. Ant gate circuit patent applicant Sumitomo Electric Gyokugyo Co., Ltd. Agent
Sickle 1) Text 2 Figure 3

Claims (1)

[Claims] At the branch point of the power transmission line, a current transformer that detects flash fault current is installed on each overhead ground wire of the branch tower, and a flash fault fault line is determined by mutually comparing the phase of the secondary current flowing through each current transformer. In addition, if the current phase of each current transformer matches,
A transmission line branch characterized in that it is determined that a flash fault has occurred in a branch tower by comparing the signal of an AND gate circuit connected to the output circuit of each current transformer with the signal of a current phase comparison circuit of each current transformer. A method for detecting flash faults at points.