JPH0619101Y2 - Transmission line fault section locator - Google Patents

Description

[Detailed Description of the Invention] The present invention is a power transmission line that directly supplies electricity to a demand side electric station such as a factory, such as an overhead power transmission line of 33 kV class or less. The present invention relates to a device to be installed under a power transmission line in order to orient.

Currently, for transmission lines of 77 kV class or higher, a method of locating the position of a failure point is adopted from an electrical phenomenon at the time of a failure at an electric station such as a power station or a substation. On the other hand, as shown in Fig. 1, in the transmission line of 33 kV class or less, the transmission line 1 from the electric power station 4 on the supply side such as a substation is branched to transmit electric power to the electric power station 6 on the demand side such as many factories. It is difficult to apply the system which locates the failure point from the electric station which is used in 77kV class or more because the number of points 2 increases and the electric phenomenon at the time of failure becomes too complicated. Not adopted.

By the way, as factory automation has progressed recently, the impact of electrical failures accompanied by short-term power outages has increased, and early detection of failure points and strengthening of countermeasures are required even for transmission lines of 33kV or less. However, for the transmission lines of 33kV class or less, the current situation is that the overhead ground line for lightning protection, which is installed in the transmission line of 77kV class or more, is not installed. Therefore, the following fault zone localization method has been proposed.

That is, if a ground fault occurs at the failure point 3 of the power transmission line 1 shown in FIG.
The fault current 7, which is usually called the zero-phase current, which returns to the earth, flows in the section from the fault location 3 to the fault location 3. The load current of the power transmission line at all times cancels the magnetic flux with each other in three phases, but the zero-phase current at the time of this failure is three-phase unbalanced, so a larger magnetic flux is generated and It is possible to generate an electromagnetic induction voltage that is larger than the normal load current. If the electromagnetic induction detection device 5 is installed in an appropriate place under the power transmission line, at the time of a failure, the electromagnetic induction due to the zero-phase current at the time of the failure occurs in the section up to the electric station 4 such as a substation and the failure point 3. Since the voltage increases, it can be distinguished from the rest of the section and the fault section can be located.

Such a method is theoretically possible, but in practice, it is usually thought that malfunctions will increase due to the electromagnetic induction noise at the time of lightning strike and the electromagnetic induction noise of peripheral electric devices, etc. Such a method has many problems in practical use and has a problem.

On the other hand, the present invention, on the other hand, when a power failure occurs in a transmission line, a protective relay operates at an electric station 4 such as a substation to stop the supply of electricity, so that the line voltage temporarily disappears. In addition to paying attention to the points and the confirmation of failure time by memory, in the social background as described above, unlike the conventional method, a device is directly installed under the transmission line and the failure section is located without malfunction. This is an attempt to put the practical method into practical use.

The principle of locating a failure section in the transmission line failure section locator according to the present invention will be described with reference to FIG.

The current situation is that the 33 kV class or lower transmission line does not have the overhead ground wire for lightning protection that is installed in the 77 kV class or higher transmission line. Therefore, FIG. 2 shows an example of waveforms of the electromagnetic induction voltage 8 under constant load, the electromagnetic induction voltage 9 during failure, and the electrostatic induction voltage 10 detected under the power transmission line. The electromagnetic induction voltage is detected by arranging electromagnetic coils horizontally under the wire at right angles to the line direction. The electrostatic induction voltage 10 is obtained by a method usually called an electric field intensity meter, that is, by detecting a potential difference generated between two electrode plates placed between the transmission line and the ground. The electromagnetic induction voltage is affected by electromagnetic induction noise from the outside due to its nature, but the electrostatic induction voltage is relatively less affected by others because the induction source is the high voltage of the transmission line. .

In the present invention, when detecting the electromagnetic induction voltage 9 due to the zero-phase current at the time of failure, the electromagnetic induction noise depends on whether the electrostatic induction voltage becomes zero or decreases after a certain time after the electromagnetic induction voltage exceeds the specified level. To prevent malfunction by determining whether the failure time is due to a fault current.Furthermore, by storing the failure time in a memory circuit and calling the failure time according to the display of the failure section when necessary, the electricity on the supply side of the substation, etc. This enables the normal operation to be confirmed by comparing it with the records at the site, and thus enables the practical application of fault location under the transmission line.

Hereinafter, the present invention will be described in detail with reference to FIG. 3, which is a circuit diagram of an embodiment of the present invention.

FIG. 3 is a circuit diagram showing an embodiment of the transmission line fault section locator according to the present invention. The entire circuit of this embodiment is installed as a device under the transmission line, such as a tower of a transmission line tower. Is.

When the voltage from the electromagnetic induction coil 11 increases and exceeds a certain level, the switch 13 from the DC power supply circuit 12 of the battery constantly charged by the solar battery is turned on. After the high-frequency induction noise is removed from the voltage from the electromagnetic induction coil 11 through the filter circuit 14, the comparison circuit 15 confirms that the voltage exceeds the constant level value for a certain period of time.
The comparison circuit 15 is provided on condition that the voltage of the electrostatic induction detection circuit 18 for detecting the potential difference between the two insulated electrode plates becomes zero or decreases from the normal value until it does not become zero.
The judgment circuit 16 judges the result of whether or not it is the failure section judged in step S6, and the display circuit 17 is operated.

Even if the electromagnetic induction voltage increases above the specified level value due to the electromagnetic induction noise from the other, if there is no change in the electrostatic induction voltage, it is judged as a malfunction and the switch 13 is opened to return to the standby state to avoid the malfunction. . The display circuit 17 has an internal clock circuit, and stores the time in the storage circuit each time a failure occurs.

When the failure display overlaps several times, this failure time is called from the display circuit 17 to the liquid crystal digital display circuit and compared with the failure time recorded at the electric station such as a substation so that normal operation can be confirmed. is there.

Since the transmission line fault section locator according to the present invention is as described above, there is an effect that it is possible to realize a fault section locator under an overhead transmission line where an overhead ground wire is not installed without malfunction.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a power transmission line, FIG. 2 is an explanatory diagram showing waveforms of electromagnetic induction voltage / electrostatic induction voltage of a transmission line, and FIG. 3 is an electric circuit diagram showing an embodiment of the present invention. is there. 1 ... Transmission line, 2 ... Branch point, 3 ... Failure point, 4 ...
Supply side electric stations such as substations, 5 ... Electromagnetic induction detection device,
6 ... Demand side electric stations such as factories, 7 ... failure current, 8 ...
… Electromagnetic induction voltage under constant load, 9… Electromagnetic induction voltage during failure, 10 ... Electrostatic induction voltage, 11 ... Electromagnetic induction coil, 12 ... Power supply circuit, 13 ... Switch, 14 ... Filter circuit , 15 ... Comparison circuit, 16 ... Judgment circuit,
17 ... Display circuit, 18 ... Electrostatic induction voltage detection circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Nobutaka Fukui 51 857, 857, Fukudome-cho, Matsuto-shi, Ishikawa (56) References JP 47-43940 (JP, A) JP 59-214778 (JP, A)

Claims (2)

[Scope of utility model registration request] Claim: What is claimed is: 1. A transmission line fault section locator installed below an overhead power transmission line in which an overhead ground wire is not installed, which circuit detects an electromagnetic induction voltage due to a line current flowing through the transmission line.
A circuit that detects an electrostatic induction voltage due to the line voltage and a detection voltage of the electromagnetic induction voltage detection circuit are compared with a specified level, and a failure detection output is generated when the detected electromagnetic induction voltage exceeds the specified level. Judgment that produces a judgment output indicating a line failure when the detection voltage of the comparison circuit and the electrostatic induction voltage detection circuit is lower than the normal value and the detection output of the electromagnetic induction voltage detection circuit is generated A transmission line fault section locator comprising a circuit and a display for indicating that the section is a fault section based on the judgment output of the judgment circuit. 2. The utility model registration, wherein the display device includes a clock circuit for measuring a failure occurrence time and a digital display for storing the failure occurrence time and calling the failure time for display. The transmission line fault section locator according to claim 1.