JPH07140182A - Optical voltage measuring apparatus - Google Patents

Abstract

PURPOSE:To enhance the measurement accuracy of an optical voltage measuring apparatus. CONSTITUTION:The optical voltage measuring apparatus comprises an intermediate electrode 20 opposing the forward end face of a conductor 11 being applied with a voltage in an enclosed case 10, a ground electrode 30 interposed between the conductor 11 and the intermediate electrode 20 with a hole 32 being provided oppositely to the forward end face of the conductor 11, an insulating spacer 21 for holding the intermediate electrode 20 on the ground electrode 30, an optical voltage sensor 40 secured to a supporting base 35 on the inside of the enclosed case 10 while opposing the intermediate electrode 20 with the voltage input terminal being connected with the intermediate electrode 20 and the ground electrode 30, and a hermetically sealed terminal 14 fixed to the enclosed case 10. The measuring apparatus further comprises a signal processing circuit 44 disposed on the outside of the enclosed case 10 in order to convert a signal from the voltage sensor 40 into a voltage on the conductor 11, and optical fibers 41, 42 for connecting the processing circuit 44 and the voltage sensor 40 through a hermetically sealed terminal 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical voltage measuring device for measuring a voltage applied to a conductor of electric equipment.

[0002]

2. Description of the Related Art FIG. 3 shows an example of the configuration of an optical voltage sensor of an optical voltage measuring device.

The optical voltage sensor includes a polarizer 44 and a quarter
It comprises a wave plate 45, an electro-optic crystal 46, and an analyzer 47. A transparent electrode 48 is vapor-deposited on the two surfaces of the electro-optic crystal 46 that are perpendicular to the optical path 49.

When a voltage is applied to the transparent electrode 48, the electro-optic crystal 46 changes its refractive index according to the applied voltage due to the electro-optic effect. This change in the refractive index shows different values depending on the X and Y directions.

The light incident along the optical path 49 is reflected by the polarizer 44.
After being converted into linearly polarized light by, the quarter-wave plate 45 becomes circularly polarized light. Next, this circularly polarized light is phase-modulated by passing through the electro-optic crystal 46 to which a voltage is applied, and becomes elliptically polarized light. Since the intensity of the elliptically polarized light is converted by the analyzer 47, the voltage applied to the electro-optic crystal 46 can be measured as the light intensity.

The voltage that can be measured by the optical voltage sensor is about several hundred volts. Therefore, when measuring a high voltage, a method is used in which the voltage is divided using an intermediate electrode, a capacitor, etc., the divided voltage is measured, and then the voltage is converted from the voltage division ratio.

FIG. 2 shows an example of a conventional optical voltage measuring device.
1 shows an optical voltage measuring device for measuring the voltage of a conductor 11 installed in a closed container 10 of a gas insulation device.

An intermediate electrode 50 located inside the closed container 10 so as to surround the conductor 11, a ground electrode 60 arranged around the conductor 11 and outside the intermediate electrode 50, and a wall surface of the closed container 10. A lead wire 51 connecting the installed insulating terminal 12 and the optical voltage sensor 40 and the intermediate electrode 50 arranged outside the closed container 10 via the insulating terminal 12.
And a lead wire 61 connecting the optical voltage sensor 40 and the ground electrode 60 via the insulating terminal 12, and a partial voltage adjustment for connecting the lead wire 51 and the lead wire 61 in parallel with the optical voltage sensor 40. A capacitor 52, a signal processing circuit 43 that calculates the voltage of the conductor 11 by exchanging optical signals with the optical voltage sensor 40, an optical fiber 41 for light transmission that connects the optical voltage sensor 40 and the signal processing circuit 43, and It is composed of a light-receiving optical fiber 42.

The intermediate electrode 50 and the ground electrode 60
Are fixed in the closed container 10 with an insulator 13 such as a spacer.

The voltage between the conductor 11 and the ground electrode 60 is
The capacitance C _T between the conductor 11 and the intermediate electrode 50, the capacitance C _S between the intermediate electrode 50 and the ground electrode 60, the capacitance C _B of the divided voltage adjusting capacitor 52, and the optical voltage sensor. It is divided by a capacitance C _{K of} 40. Therefore, the voltage applied to the optical voltage sensor 40 can be arbitrarily adjusted by changing the capacitance C _B of the divided voltage adjusting capacitor 52.

Of the voltage between the conductor 11 and the ground electrode 60, a voltage of several hundred volts divided by C _T , C _S , C _B , and C _K causes the lead wire 51 and the lead wire 61 to isolate the insulated terminal 12. It is guided to the optical voltage sensor 40 via the. The optical voltage sensor 40 is supplied with light from the signal processing circuit 43 through the light-transmitting optical fiber 41.
Then, the light intensity is converted by the above-described method and is sent to the signal processing circuit 43 through the light receiving optical fiber 42. In the signal processing circuit 43, the optical voltage sensor
The voltage applied to 0 is obtained, and the voltage of the conductor 11 is calculated from the known voltage division ratio.

[0012]

When the divided voltage adjusting capacitor 52 is not used, the voltage between the conductor 11 and the ground electrode 60 is divided by C _T , C _S , and C _K. When the capacitance of the optical voltage sensor 40 is fixed, the voltage is applied to the optical voltage sensor 40 only by changing the distance between the conductor 11 and the intermediate electrode 50 and the distance between the intermediate electrode 50 and the ground electrode 60. The voltage can be adjusted.
However, practically, for example, when a voltage of several hundred volts is applied to the optical voltage sensor 40 when a voltage of 72 kilovolts is applied to the conductor 11 having a diameter of 100 mm, the diameter of the ground electrode 60 is set to 200 mm.
The distance between the intermediate electrode 50 and the ground electrode 60 is about 0.
2 mm. It is very difficult to manufacture the intermediate electrode 50 and the ground electrode 60. Therefore, in the conventional optical voltage measuring device, the conductor 1
In the case where the distance between 1 and the intermediate electrode 50 and the distance between the intermediate electrode 50 and the ground electrode 60 are made easy to manufacture,
The divided voltage adjusting capacitor 52 is indispensable for adjusting the voltage applied to the optical voltage sensor 40.

However, this conventional optical voltage measuring device has a drawback that the temperature characteristic of the divided voltage adjusting capacitor 52 largely appears as a measurement error factor of the optical voltage measuring device.

Therefore, the present invention improves the measurement accuracy of the optical voltage measuring device by obtaining the voltage applied to the optical voltage sensor with a structure that does not require a capacitor for adjusting the divided voltage.

[0015]

[Means for Solving the Problems] An intermediate electrode facing a tip surface of a conductor to be charged in a sealed container, and a portion arranged between the conductor and the intermediate electrode and facing the tip surface of the conductor. A ground electrode with a hole in the ground, an insulating spacer for holding the intermediate electrode on the ground electrode, and a fixing base fixed to the inner surface of the closed container facing the intermediate electrode by a support stand, and the voltage input terminal to the intermediate electrode and the ground electrode. A connected optical voltage sensor, a sealed terminal attached to a sealed container, a signal processing circuit arranged outside the sealed container for calculating the voltage of a conductor from an optical signal of the optical voltage sensor, and this signal processing circuit. The optical voltage sensor and the optical fiber connected to each other via the sealed terminal.

[0016]

In the optical voltage measuring device of the present invention having the above-described structure, a voltage of several hundreds of volts applied to the optical voltage sensor can be obtained only by the intermediate electrode without using a divided voltage adjusting capacitor. The voltage can be accurately measured without being affected by the temperature characteristics of the divided voltage adjusting capacitor.

[0017]

1 is an example of an optical voltage measuring device according to the present invention,
The intermediate electrode 20 located inside the grounded closed container 10 of the gas-insulated equipment and facing the tip surface of the conductor 11 is installed, and the conductor 11 is provided between the tip surface of the conductor 11 and the intermediate electrode 20. The ground electrode 30 having the holes 32 is arranged in the facing portion. The ground electrode 30 is electrically and mechanically connected to the closed container 10, and the intermediate electrode 20 is an insulating spacer 2.
It is fixed to the ground electrode 30 by 1. Optical voltage sensor 4
0 is fixed to the inside of the closed container 10 having the same potential as the ground electrode 30 via the support 35, and its voltage input terminal is connected to the intermediate electrode 20 and the ground electrode 30. Further, the signal processing circuit 43 is disposed outside the closed container 10 and the sealed terminal 14 is provided.
The optical voltage sensor 40 is optically connected to the optical voltage sensor 40 via the optical fiber 41 for light transmission and the optical fiber 42 for light reception.

When a voltage is applied to the conductor 11, an electric field is generated between the conductor 11 and the ground electrode 30. However, since the ground electrode 30 has the hole 32, a certain proportion of the hole 32 is provided according to the size of the hole 32. The electric field leaks to the side of the intermediate electrode 20, and a voltage is generated between the ground electrode 30 and the intermediate electrode 20 depending on the distance between the conductor 11 and the ground electrode 30 and the distance between the ground electrode 30 and the intermediate electrode 20.

In the embodiment, a voltage of 72 kilovolts is applied to the conductor 11 having a diameter of 100 mm to form a ground electrode 30 having a thickness of 10 mm and a hole 32 having a diameter of 20 mm at a position 100 mm away from the end face of the conductor 11. By providing the intermediate electrode 20 having a diameter of 10 mm and a thickness of 2 mm at a position 10 mm away from the ground electrode 30, the ground electrode 30 is provided.
A voltage of approximately 300 volts is obtained between the intermediate electrode 20 and the intermediate electrode 20. This makes it possible to measure a highly accurate voltage that does not change with temperature.

[0020]

According to the present invention, since the voltage of several hundreds of volts applied to the optical voltage sensor can be obtained only by the intermediate electrode without using the divided voltage adjusting capacitor, the temperature of the divided voltage adjusting capacitor is reduced. The voltage to be measured can be accurately measured without being affected by the characteristics.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of an optical voltage measuring device of the present invention.

2A and 2B are views showing an example of a conventional optical voltage measuring device, FIG. 2A is a schematic sectional view in an axial direction, and FIG. 2B is a schematic sectional view in a radial direction.

FIG. 3 is a diagram showing an example of a configuration of an optical voltage sensor.

[Explanation of symbols]

 10 Airtight Container 11 Conductor 20 Intermediate Electrode 21 Insulating Spacer 30 Grounding Electrode 32 Hole 35 Support Stand 40 Optical Voltage Sensor 41 Optical Fiber 42 Optical Fiber 43 Signal Processing Circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Eiji Itakura Eiji Itakura 3-chome, Yoshino-cho, Nishibiwajima-cho, Nishikasugai-gun, Aichi Prefecture Takatake Manufacturing Co., Ltd. Technology Development Center

Claims (1)

[Claims] 1. An intermediate electrode facing a tip surface of a conductor to be charged in a closed container, and a hole provided in a portion facing the tip surface of the conductor, the intermediate electrode being disposed between the conductor and the intermediate electrode. Ground electrode, an insulating spacer for holding the intermediate electrode to the ground electrode, and an optical type that connects the voltage input terminal to the intermediate electrode and the ground electrode, while fixing it to the inner surface of the closed container facing the intermediate electrode with a support. A voltage sensor, a sealed terminal attached to a sealed container, a signal processing circuit arranged outside the sealed container for calculating the voltage of a conductor from an optical signal of an optical voltage sensor, the signal processing circuit and the optical voltage An optical voltage measuring device comprising an optical fiber connecting to a sensor via the sealed terminal.