JPH08304477A - Method for detecting charging/interruption of line - Google Patents

Abstract

PURPOSE: To avoid noise influences to enhance the reliability of a system and make the system compact, by setting an optical magnetic sensor in a line, converting an output from the optical magnetic sensor to an electric signal and detecting whether the line is charged or shut down. CONSTITUTION: Optical magnetic sensors 2A-2C are set in a power feed line 1, and outputs of the sensors are guided to O/E converters 4A-4C in a digital operating device 8 via optical fibers 3A-3C and converted to electric signals. The electric signals are compared with a predetermined value at comparators 5A-5C, and converted to 'high' or 'low' signals. A logic circuit 6 operates 2outof3(3 C2 ) based on the outputs from the comparators 5A-5C. For example, if two or more of the three outputs are 'high', it is detected that a voltage is present. If two or more of the three are 'low', it is detected that the power line is shut down. A failure detection circuit 7 detects from outputs of the O/E converters 4A-4C whether or not a system is abnormal. When the abnormality is detected, which of the system fails is informed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noncontact detection method for detecting charging / power failure (charging / power failure) of a transmission line or the like.

[0002]

2. Description of the Related Art Heretofore, as a method of detecting charging / outage of this kind, an electric method utilizing electrostatic capacity has been known.

[0003]

However, a device utilizing electrostatic capacitance is susceptible to noise due to lightning, etc., and is relatively large in size, which causes a problem in space. Therefore, an object of the present invention is to provide a detection method that is small and compact and is not easily affected by noise.

[0004]

In order to solve such a problem, according to the present invention, an optical magnetic field sensor is provided for a line, and an output from the optical magnetic field sensor is converted into an electric signal to charge or charge the line. It is characterized by detecting a power failure.

[0005]

By using the optical magnetic field sensor to detect the presence or absence of the voltage on the line in a non-contact manner, the influence of noise is suppressed, the reliability is improved, and the size and the size are reduced.

[0006]

1 is a block diagram showing an embodiment of the present invention. In the figure, 1 is a power transmission line, 2A to 2C are optical magnetic field sensors, 3A to 3C are optical fibers, 8 is an optical / electrical converter (O / E) 4A to 4C, comparators 5A to 5C, and a logic circuit 6 And a failure detecting circuit 7 and the like. Although three optical magnetic field sensors are provided here, this is for ensuring reliability, and basically only one is required.

That is, the optical magnetic field sensors 2A to 2C are provided for the power transmission line 1, and the outputs thereof are optical fibers 3A to 3C.
O / E converter 4A in the digital arithmetic unit 8 via C
~ 4C, where it is converted to an electrical signal. This electric signal is compared with a predetermined value by the comparators 5A to 5C and converted into "high" and "low" signals. The logic circuit 6 outputs 2outof3 based on the outputs from the comparators 5A to 5C.
( ₃ C ₂ ) is calculated, and for example, if two or more of the three outputs are “high”, it is determined that “voltage is present”, and if “low”, “power failure” is determined. The failure detection circuit 7 includes an optical / electrical converter 4
Whether or not the system is abnormal is determined from the outputs of A to 4C, and when the system is abnormal, which system is in failure is notified.

Now, the principle of the optical magnetic field sensor will be described with reference to FIG. Polarizer 1 on crystal 10 that transmits light
When linearly polarized light enters via 1, when a magnetic field is applied,
The plane of polarization rotates in proportion to the strength H of the magnetic field. Analyzer 12
When the rotation angle detected by is θ, the strength H of the magnetic field when θ <π / 4 is proportional to the strength P of the transmitted light.
It is generally well known as the so-called Faraday effect. Therefore, if a crystal such as quartz is used as the light transmitting substance, it can be used as an optical magnetic field sensor.

The intensity P of the transmitted light is expressed as P = P0 · (1 + sin2θ), where P0 is the intensity of the transmitted light when H = 0. From this, it can be seen that whether or not there is a voltage in the cable 1 can be known by the intensity P of the transmitted light from the optical magnetic field sensor.

[0010]

As described above, according to the present invention, since the optical magnetic field sensor is used, it is possible not only to avoid a malfunction due to noise, but also to obtain an advantage that a light weight and compact structure can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating the principle of an optical magnetic field sensor.

[Explanation of symbols]

1 ... Power transmission line, 2A-2C ... Optical magnetic field sensor, 3A-
3C ... Optical fiber, 4A-4C ... Optical / electrical signal converter,
5A to 5C ... Comparator, 6 ... Logic circuit, 7 ... Failure detection circuit, 8 ... Digital arithmetic unit, 10 ... Crystal, 11 ... Polarizer, 12 ... Analyzer.

Claims (1)

[Claims] 1. A line charge / power failure detection, wherein an optical magnetic field sensor is provided for the line, and an output from the optical magnetic field sensor is converted into an electric signal to detect charging or power failure of the line. Method.