JPH04307370A - Photoelectric current voltage sensor - Google Patents

Abstract

PURPOSE:To obtain a photoelectric current/voltage sensor which is highly reliable, inexpensive, and saves space. CONSTITUTION:A cylindrical ring 4 is placed concentrically with a conductor 2 and is sealed to a tank 1 outside the conductor 2 which is housed within a tank 1 where an insulation gas is filled, a polarization surface storage optical fiber 5 is wound around the ring 4 for a plurality of times spirally, and a light path is constituted in a same direction as a magnetic field which is generated due to current flowing at the conductor 2. A photoelectric sensor 10 is connected to the ring 4 or between a terminal which is at the same potential and is connected electrically to the ring 4 and the tank 1 at the ground potential.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a photocurrent sensor using a polarization-maintaining optical fiber and a photovoltage sensor using a Pockels element for measuring current flowing through a conductor in a gas-insulated switchgear or a gas-insulated busbar. It is related to.

0002

[Prior Art] Conventionally, the measurement of current flowing through a polarization-maintaining optical fiber using the Faraday effect involves winding the optical fiber directly around the outer periphery of a conductor in a spiral shape, forming an optical path in the direction of the magnetic field, and injecting light into the optical fiber. This was done by measuring the change in the emitted light due to the rotation of the plane of polarization by the magnetic field.

An example of the prior art is shown in FIG. Generally, a busbar of a gas-insulated switchgear or a gas-insulated busbar is composed of a tank 1a filled with an insulating gas and a conductor 2a supported by an insulator (not shown). In order to detect the current flowing through the conductor 2a, a polarization maintaining optical fiber 5a is connected to the conductor 2a.
By winding the conductor 2a, an optical path is formed in the same direction as the magnetic field generated by the current flowing through the conductor 2a, and by providing a polarizer 15 and an analyzer 16 at both ends of the optical path, the current flowing through the conductor 2a is controlled by the Faraday effect. It is something to detect. The incident light 17 and the output light 18 are transmitted between the tank 1a side and the conductor 2a by spatial transmission of light, and then connected to the airtight connector 7a.
, via the optical fiber cable 11 outside the tank 1a,
The signal is transmitted to a light emitting/receiving section, an O/E converting section, and a signal output section (not shown). Note that a shield 19 is fixed to the conductor 2a with bolts 20 for the purpose of protecting the polarization-maintaining optical fiber 5a from distortion of the electric field and the high electric field of the polarization-maintaining optical fiber 5a.

The voltage between the conductor 2a and the tank 1a is the voltage between the conductor 2a and the tank 1a.
A cylindrical ring 4 is placed outside of the tank 1a, and is insulated and fixed to the tank 1a to form a floating electrode. The voltage induced is connected to a voltmeter (not shown) through a lead wire 21 and measured.

The voltage V2 induced in the secondary capacitance (C2) 9 is V2=C1V/(C1+C2) where V is the voltage between the conductor 2a and the tank 1a, C1
is the primary capacitance.

[0006]

[Problem to be solved by the invention] Conductor 2a and tank 1
Transmission of light between conductor 2a and tank 1a may be carried out using optical fibers, but protection from high electric fields and mechanical stress caused by displacement between conductor 2a and tank 1a caused by vibration, heat, etc. are issues. Therefore, spatial transmission of light without using fibers is often used. In this case, assembly precision is critical, and it is also necessary to take measures to prevent misalignment of the optical axis due to thermal deformation, vibration, etc.

[0007] Furthermore, a polarization maintaining optical fiber 5 is connected to the conductor 2a.
Since the conductor 2a and other optical components are attached, there is a risk that the heat generated by the conductor 2a will have an adverse effect. Moreover, in order to measure the voltage, the ring 4 is provided only for the purpose of dividing the voltage, which not only increases the size of the device, but also requires a secondary capacitance 9 and a voltage measuring device (not shown). Since these are connected by a lead wire 21, it is necessary to eliminate the influence of electromagnetic noise, and since the voltage division ratio changes depending on the length of the lead wire 21, it is necessary to correct the voltage division ratio. The present invention was devised in view of the above circumstances, and detects current by winding a polarization-maintaining optical fiber around the outer circumference of a ring of floating electrodes, and connects a photovoltage sensor to the secondary side of the ring. The present invention aims to provide a photocurrent and voltage sensor that is highly reliable, inexpensive, and space-saving by detecting voltage.

[0008]

[Means for solving the problem] A cylindrical ring is placed coaxially with the conductor on the outside of the conductor housed in a tank filled with an insulating gas and is fixed to the tank, and the polarization plane is attached to the outer periphery of the ring. The storage optical fiber is wound once or multiple times in a helical manner to create an optical path that is the same as the magnetic field generated by the current flowing through the conductor. and the ring or
An optical voltage sensor is connected between a terminal at the same potential electrically connected to the ring and a tank at ground potential, and the voltage is converted into an optical signal and transmitted.

[0009]

[Operation] The above eliminates the need for spatial transmission of light, and also eliminates the risk of exposing optical fibers and other optical system components to high temperatures and high electric fields. In addition, since the ring for winding the optical fiber and the ring for voltage division can be used together, it can be made smaller, and since transmission is performed by light, it is not affected by electromagnetic noise, and the secondary side capacitance Since a high-impedance optical voltage sensor and an optical fiber are connected to the sensor, there is no need to correct the voltage division ratio.

0010

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to FIG. Note that the same parts as in FIG. 2 are given the same numbers, and redundant explanations will be omitted.

A cylindrical ring 4 is disposed outside the conductor 2 and coaxially with the conductor 2, and is connected to the tank 1 by a bolt 14.
is fixed to. A polarization-maintaining optical fiber 5 is wound around the outer periphery of the ring 4 once or multiple times in a spiral shape, forming an optical path in the same direction as the magnetic field generated by the current flowing through the conductor 2. Both ends of the polarization maintaining optical fiber 5 are connected to an airtight connector 7 provided with a polarizer 15 and an analyzer 16. Further, since the polarization maintaining optical fiber 5 is attached to the tank 1 side, there is no need for spatial transmission of light, and extraction to the outside is performed by the airtight connector 7.

Furthermore, by connecting the optical voltage sensor 10 between the terminal 6 at the same potential as the ring 4 and the tank 1 at the ground potential or the terminal box 3 at the ground potential, it is possible to Voltage measurement can be performed using the common ring 4.

[0013]

Effects of the Invention In the present invention, all the optical components such as the polarization maintaining optical fiber 5, the polarizer 15, and the analyzer 16 are arranged outside the ring 4 attached to the tank 1. Since there is no need to worry about exposure to high temperatures and there is no need for spatial transmission of light, a highly reliable and inexpensive photocurrent voltage sensor can be provided.

Furthermore, space can be saved by using both the fiber winding ring and the partial pressure ring. Moreover, since an optical voltage sensor is used for voltage detection, electromagnetic noise resistance is improved and complicated voltage divider corrections can be avoided.

[Brief explanation of drawings]

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

FIG. 2 is a diagram showing an example of conventional technology.

[Explanation of symbols]

1 Tank 2 Conductor 3 Terminal box 4 Ring 5 Polarization maintaining optical fiber 6 Terminal 7 Airtight connector 8 Primary side capacitance 9 Secondary side capacitance 10 Photovoltage sensor 11 Optical fiber 12 Insulating washer 13 Insulation collar 14 bolts 15　Polarizer 16 Analyzer 17 Incident light 18 Output light 19 Shield 20 bolts 21 Lead wire

Claims (1)

[Claims] 1. A cylindrical ring is disposed coaxially with the conductor on the outside of the conductor housed in a tank filled with insulating gas and is fixed to the tank, and the polarization plane is preserved on the outer periphery of the ring. The optical fiber is wound once or multiple times in a spiral shape, and an optical path is formed in the same direction as the magnetic field generated by the current flowing through the conductor, and the ring or a wire at the same potential electrically connected to the ring is formed. A photocurrent voltage sensor characterized in that a photovoltage sensor is connected between a terminal and a tank at ground potential.