JPS6188167A - Device for discriminating section of transmission line - Google Patents

Abstract

PURPOSE:To prevent an accident section based upon physical damage of CT due to noise or high voltage from misjudge by detecting a magnetic field by optical magnetic sensors and transmitting the detected results to signal processing circuits through optical fibers. CONSTITUTION:The optical magnetic sensors 2a, 2b are arranged on both the end points A, B of a section L. Optical outputs corresponding to sequence currents which are outputted from the sensors 2a, 2b are transmitted to the signal processing circuits 4a, 4b through two-core optical fiber cables 3a, 3b. The circuits 4a, 4b convert the optical signals transmitted through the cables 3a, 3b respectively into electric signals and transmit the electric signals to a decision circuit 5. The circuit 5 decides the existence of earthing and the earthing section on the basis of the transmitted signals.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a section discriminating device for a power transmission line, particularly to a section discriminating device for a pipeline aerial power transmission line.

[Prior Art] A conduit aerial power transmission line (hereinafter referred to as GIL) has a center conductor and a metal sheath that are held together by an insulating spacer, and M t' in the space between the center conductor and the metal sheath. It is filled with R gas, for example, SF G gas.

Since such a GIL is used with a sheath solid bond, a sheath current of approximately the same magnitude as the conductor current flows through the sheath in the opposite direction.

In such a GIL, a ground fault may occur even though the MTi pressure JFf is sufficiently established, and countermeasures against this are required.

Therefore, when a ground fault occurs, it is necessary to monitor whether the ground fault has occurred in a predetermined GIL section or outside the section connected to this GIL section.

The conventional method for countering this problem is to install current transformers (hereinafter referred to as CT) at both ends of a defined section, and to
There is a method of detecting the fault point using the (if current) from T.However, in this method using C[, C-[
The distance between the CT and the equal signal processing circuit that detects the signal PTi is long, and the signal lead wire is an electric wire, so noise may be picked up along the way and the CT may be exposed.
Since it is attached to a 6-voltage wire, erroneous judgments may occur due to contact between the CT and the ^-voltage wire or physical destruction of the CT.

Another drawback was that the shape of the CT was large.

[Summary of the Invention] An object of the present invention is to eliminate the drawbacks of the above-mentioned method using two CTs, and to provide an accident section discriminating device that has a simple configuration and does not cause misjudgment.

If approved, this invention replaces two CTs with magnetic field detection sensors installed at each end of a predetermined GIL section, and this 2ff! The signal from the magnetic field detection sensor of if is transmitted to the optical-to-electrical conversion circuit through an optical fiber, and the signal from this conversion circuit is used to determine whether
This is to determine whether there is a ground fault or not and the accident section.

The objects and other objects and features of the invention will become more apparent from the detailed description given below with reference to the drawings.

[Embodiment of the Invention] FIG. 1A is a block diagram of the configuration of a GIL grade accident zone determination device using an optical magnetic field sensor, which is an embodiment of the present invention. In FIG. 1A, the section Lt of GILl
fi monitored. Optical magnetic field sensors 2a and 2b are installed at both end points A and B of the section, respectively. The sheath Tram compatible optical outputs derived from both magnetic field sensors 2a and 2b are transmitted to signal processing circuits 4a and 4b by two-core optical fiber cables 3a and 3b, respectively. Signal processing circuit 4a.

4b is the optical signal transmitted by the optical fiber cables 3a and 3b, respectively, and the ratio of 1% to 13% according to this optical signal.
and transmits it to the discrimination circuit 5. The determination circuit 5 determines the presence or absence of a ground fault and the ground fault section based on the transmitted signal. FIG. 1B is a block circuit diagram of the discrimination circuit 5 of FIG. 1A. In FIG. 1B, the discrimination circuit 5 is composed of a multiplier 6 which multiplies the amplitudes of the inputs X and Y from the signal processing circuits 4a and 4b by 1i)tiI. This I! ) The sensor 6 is a noise and magnetic field sensor 2a.

2 hours! This is provided to prevent erroneous judgments due to defects such as 54-year malfunctions.

First, an optical magnetic field sensor based on the present invention will be explained.

FIG. 2 is a diagram showing the basic principles of a b1 field sensor.Linearly polarized light having a constant polarization direction A is applied to a Faraday element 7 made of, for example, a BSO crystal. An electric field H is applied to this Faraday element 7 in parallel to the traveling direction of the incident light. When the incident light passes through the Faraday element 7, it undergoes Faraday rotation and the direction A of the incident light
is rotated by a constant angle φ. Therefore, the transmitted light of this Faraday element 7 becomes direct M light in the vibration direction B.The strength of the magnetic field is H, and the length of the Faraday element 7 is 9. If the Bell f constant is Ve, then the rotation angle φ is expressed as φ=ve −H − Garden (1).

FIG. 3 is a structural diagram of a magnetic field sensor that utilizes this Faraday rotation. (The 1-field sensor 2 uses a BSO single crystal as the Faraday element 7. This Faraday element 7 is covered with a dielectric multilayer reflection f18 except for the incident light side and the transmitted light side.The incident light side of this Faraday element 7 A polarizer 9 is installed to convert the beam into linear quaternary light. Also, for transmitted light measurement, an analyzer 10 whose optical axis forms an angle of 45° with the analyzer 9 is installed. Between the photon 10 and the Faraday element 7, there is an optical rotator 1 that rotates the optical axis of the transmitted light by a certain angle.
1 is added.

Transmission rate T of this sensor 2 (intensity ratio of transmitted light and incident light)
is T = (1+sln 2φ), / 2 ・(
2). Under the condition of 2φ × 1, formula (2)%
The formula %(3 and 'cl Z) ,, where the magnetic field H is H, stn <0
At the 15th point of the police box ρ ship 17 expressed in degrees Celsius, the transmission {PT is as shown in equations (1) and (3)], 1= (1'-2Ve -H,!-, eye 1f
, ri [・ρ, ) / 2. By finding the ratio (variable, 11.ribosa) of the two components and the alternating current component, we can calculate the strength of the AL field, H6 can be found.

The fourth step is to use the magnetogastric sensor 2 described above to find the magnitude of the applied magnetic field 1.a) Basics of the 151 field sensor circuit? 1 configuration C
be. In FIG. 4, a constant z is output from the signal processing circuit 12.
No. 13 is applied to the light emitting diode 13.

The light-emitting diode responds to this (No. 3) by transmitting a light signal of a certain intensity through the light-emitting device 1 to the magnetic field sensor → L2.
There are people in the middle of the day. The transmitted light 1 of the field sensor 2 is transmitted to the upper diode 14 through the optical fiber cable 3. Diodes 14 to 14 provide electrical signals responsive to this transmitted light to the equal signal processing circuit 12. Signal processing circuit 12
calculates the ratio of the DC component to the AC component of this electric signal, and outputs 43 t of electricity according to the magnitude and frequency of the magnetic field H applied to the magnetic field sensor 2.

This applied magnetic field H is caused by the sheath current. Therefore, since the strength of the magnetic field H is proportional to the magnitude of the sheath 'I'':1 current, a change in the strength Ha of the magnetic field H corresponds to a change in the sheath current.In other words, the signal processing circuit 12 The level of the derived voltage signal corresponds to the magnitude of the sheath current. Therefore, by detecting and determining the signal derived by the signal processing circuit 12, it is possible to detect a change in the magnitude of the sheath current.

FIG. 5 is a list of the operations of the discrimination circuit 5. Hereinafter, the three-fault section discrimination method will be described with reference to FIGS. 1B and 5.

First, let's consider the case where jikyoku occurs outside the interval.

When grounding occurs, the sheath current increases. Since the ground current occurs outside the section, the phases of the sheath currents flowing to points A and B are almost the same. In response to this increased sheath T1 flow, l:f,, the moon (*""; salmon from the processing circuits 4a and 4b) is introduced into the cylinder 6). Since the nov device 6 outputs the amplitude of its inputs X and Y by 4 times, the output signal from the step n T5 G has an input signal whose amplitude has further increased on the positive and n sides, as shown in FIG. a @ roar. This output signal is compared with reference set values provided on the positive side and the n side. This output signal level is the reference setting for both
If it exceeds , it is determined that the land is outside the section.

Next, let us consider the case where a land position occurs within the interval.

At this time as well, the sheath current increases when the area is outside the range. However, the phases of the sheath currents at point A J3 and point B t:1 differ by approximately 180° (the sheath current is alternating current). For this reason, the signal processing circuits 4a and 4b
The signals given by the two also have a phase difference of 180° from each other. i
t) + ii 6 multiplies these signals whose phases are 180657, so as shown in FIG.
The output signal from nff! The signal only for 11 is roaring. Therefore, if the output level of this output signal does not exceed the positive reference setting value and exceeds the negative reference setting value, it is determined that there is a ground fault within the section.

The accident section identification system is structured as described above, so
It is possible to determine the section of a geogaku, and at the same time, it is also possible to determine the presence or absence of a geogaku.

FIG. 6 is a block diagram of the configuration of the discriminating circuit 5 which is another example of this firing. In FIG. 6, the discrimination circuit 5 calculates the amplitude of the human forces X and Y by T2, and
tt) Calculator 1G, in which an inverting circuit 17 for inverting the human input Y is connected in series to one input section, are connected in parallel to each other.

FIG. 7 is a diagram showing the operation of the discriminating circuit 5 using the above-mentioned hanging lamps 15 and 16.

The operation of another example of the real muscle according to the present invention will be described with reference to FIGS. 6 and 7.

Since the inverter circuit 17 is connected in series to the human power section of the hanging device 16, the input signal Y of one of the inverter circuits has a phase of 18
06 shift. Therefore, when the ground fault is outside the section,
Signals with a phase difference of 180°rA are multiplied by t'7F51
6 is input. Conversely, when a ground fault occurs within the section, the phase! The same signal is input to the 11F mouthpiece 16. As shown in FIG. 7), when a ground fault occurs outside the section, only the output fzf'3 level of the hooker 15 exceeds the positive reference setting value. Further, when a ground fault occurs within the interval, only the output signal level on the positive side of the multiplication 1516 exceeds the base IPπ2 constant Inn on the positive side. Even with this configuration, it is possible to determine whether or not there is a ground fault section in the person in charge of the above-described embodiment of the invention.

[Effects of the Invention] As described above, in the accident zone discrimination device according to the present invention, two magnetic field sensors are used instead of the conventional accident zone discrimination device using two CTs, and the No. 13 lead wire is used. An optical fiber is used as an optical fiber, and an 11-to-zero circuit is used as a separate circuit. Therefore, it is possible to clearly determine the accident zone and the presence or absence of a ground fault without misjudgment by drawing a small and in-cylinder equipment.

13. In the second embodiment, one field was detected for the sheath current of the conduit aerial power transmission line, but if it is the magnetic field corresponding to the center conductor current rather than the sheath current, the tube Transmission 7r other than road power transmission lines? It can also be applied offshore, and the same effects as the above-mentioned embodiments can be obtained.

[Brief explanation of drawings]

Figure 1A shows the fall 1 of the accident section map 1j according to the present invention.
~ FIG. 2 is a block diagram of the configuration of a locator. The 1st B port is the 1st
It is a block diagram of the discrimination circuit of a Δ diagram. FIG. 2 is a diagram showing the operating principle of a Faraday element. FIG. 3 is a diagram showing Mizo of the LO';it part of FIG. 1A. FIG. 4 is a block diagram of the basic configuration of the fQ product sensing circuit. FIG. 5 is a diagram showing signal waveforms in each portion of FIG. 1A. FIG. 6 is a block diagram of the configuration of a discriminating circuit according to an embodiment of the present invention. FIG. 7 is a signal waveform diagram at each part of FIG. 1A in J3 in another example of an actual plane of the present invention. In the figure, 1 is GIL, 7 is Faraday element, 2.2
a and 2b are magnetic field sensors, 4a and 4b are signal processing circuits, 5 is a discrimination circuit, 6.15.164; is a hanging device, and 17 is an inverter. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Figure 1A Urn Figure 1B Figure 2 Figure 3I21 Figure 4

Claims (3)

[Claims] (1) Detection means for detecting the level of the current, installed at both ends of a defined section of a power transmission line that transmits current, and detecting the signal derived by the detection means and detecting the fault section of the power transmission line. A power transmission line section discriminating device comprising a discriminating means for discriminating a magnetic field, the detecting means detecting a magnetic field induced by the current and converting the detected magnetic field into an optical signal, and a magnetic field-optical converting means for detecting a magnetic field induced by the current and converting the detected magnetic field into an optical signal. The power transmission line section discriminating device further includes an optical-to-electrical conversion means for converting into an electrical signal, and the discriminating means includes at least one multiplier inputting the signal from the detecting means. (2) The power transmission line section discriminating device according to claim 1, wherein the magnetic field-light conversion means is an optical magnetic field sensor using Faraday rotation. (3) The discrimination means includes a first multiplier and a second multiplier each having two input terminals, and an inverting circuit is connected in series to one input terminal of the second multiplier. A power transmission line section determination device according to claim 1.