JPS59155765A - Voltage measuring apparatus - Google Patents

Abstract

PURPOSE:To enable the detection of voltages of conductors in phases with one photovoltage sensor by electrostatically shielding intermediate electrodes for capacitively dividing voltages of conductors in varied phases of a 3-phase package electric conductor so as to measure a conductor voltage without said measurement being affected by other phases. CONSTITUTION:An intermediate electrode 4-U is arranged between a conductor 3-U and a shield tube 2-U insulated from both. A voltage Vu of the conductor 3-U is induced in the intermediate electrode 4-U as divided by electrostatic capacity between the shield tube 2-U and the intermediate electrode 4-U and the conductor 3-U and the intermediate electrode 4-U. Likewise, voltages Vv and Vw are induced in intermediate electrodes 4-V and 4-W. The voltages Vu, Vv and Vw are inputted sequentially into a photovoltage sensor 6 with a changeover switch 5 to be converted into light signals, which are taken out through an optical fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage measuring device for measuring conductor voltage of power equipment such as a substation.

Traditionally, potential transformers PT, capacitor-type potential transformers PD, etc. have been used as the main tools for measuring conductor voltage in power equipment, but they have drawbacks such as large size and high price, so new methods are needed. It is requested. As one method, a method has been proposed in which an element with an electro-optic effect is used to optically measure the voltage Y. However, in three-phase finger-shaped electrical equipment, the influence of the shadow #χ from other phase conductors and the error There was a sound. Furthermore, since optical voltage sensors and optical fibers are currently relatively expensive, there was a desire to make them cheaper.

This invention has been made in view of the above-mentioned conventional problems, and it prevents static electricity in each part of each phase conductor Y of a three-phase collective electric conductor by using a shield tube at ground potential, and between the shield tube and each conductor. An intermediate electrode is arranged, a changeover switch is provided in a portion surrounded by a shield tube, and the voltage of the intermediate electrode is sequentially switched and inputted to a photovoltage sensor, and the voltage of the intermediate electrode is guided to the outside of the photovoltage switch for time-division processing. By doing so, it is possible to detect the voltage of each phase conductor with a single optical voltage sensor without being affected by other phases, and it is manufactured at a lower cost than before.
DESCRIPTION OF THE PREFERRED EMBODIMENTS It is an object of the present invention to provide a voltage measuring device 7 that can be used in various ways.

In the figure, reference numeral 1 denotes a metal outer cylinder of a three-phase electric conductor, which is kept at ground potential. 2-U, 2-V and 2-W are shielded tubes of a certain length and are kept at ground potential, and each phase conductor 3-U, 3-V and 3- of the three-phase collective electric conductor
W Y Provides electrostatic protection from other parts. 4-U,
4-V and 4-W are intermediate electrodes, respectively conductor 3-
U and shielded tube 2-U, conductor 3-V and shielded tube 2-v
1 conductor 3-W and the shield tube 2-W at the longitudinal center of the shield tube and on the center side of the metal outer cylinder 1, insulated from other parts. Reference numeral 5 designates a changeover switch, which is fixed to the outside of the shielded tubes 2-U, 2-V, 2-W17), in the central part 0 of the metal outer cylinder 1 surrounded by the three shielded tubes in this embodiment. The switching output is guided to the optical voltage sensor 6. The input side of the changeover switch 50 is the intermediate electrode 4
-U, 4-V.

4-W via a lead 7, and the intermediate electrode 4
-U, 4-V, 4-W voltage switching output. Reference numeral 8 denotes a signal transmission device, which converts the optical signal into an electrical signal and transmits it to a voltage measuring device (not shown). The optical signal output from the optical voltage sensor 6 is guided to the outside of the metal outer cylinder 1 via the optical fiber 9-1, 9-22 and input to the signal transmission device 8.

Reference numeral 10 denotes a switch changeover control device, which supplies a changeover command signal to the changeover switch 5 via a signal line 11. Reference numeral 012 designates an airtight terminal board which receives the signal and processes the optical signal input in a time-division manner.

In this configuration, the intermediate electrode 4-U is disposed between the conductor 3-U and the shield tube 2-U so as to be insulated from both. The voltage Vt of the conductor 3-U, which is divided by the electrostatic density between the conductor 2-U and the intermediate electrode 4-U and between the conductor 3-U and the intermediate electrode 4-U
t is induced.

The same applies to the other intermediate electrodes 4-V and 4-w, each with a voltage V proportional to the voltage of the conductor 3-4.3-W.

VW is induced. These induced voltages are generated at the intermediate electrode 4
Since -U, 4-V, and 4-w are electrostatically shielded from each other, they are not affected by other conductors. Voltage vtL, vv, V
W is input into the optical pressure sensor 6 in a predetermined order by the changeover switch 5, where it is sequentially converted into an optical signal corresponding to a voltage level, and sequentially taken out to the outside via an optical fiber. The optical signal taken out to the outside is converted into a confidential electric signal by the signal transmission device 8, and is outputted in time series.

In this embodiment, the changeover switch 5 is located at the center of the metal outer cylinder 1, and the intermediate electrodes 4-U, 4-V, 4-wy are located on the center side. -V,
The impedance between 4-W and the optical voltage sensor 6 is small,
This can prevent the input level of the optical voltage sensor 6 from decreasing and noise from entering.

As described above, according to the present invention, since the intermediate electrodes that divide the voltage of each phase conductor in a dense manner are each prevented from electrostatic discharge,
Conductor voltage can be measured accurately without being affected by other phases, and the voltage of each phase conductor can be detected with a single optical voltage sensor, making it cheaper to manufacture than conventional methods. I can do it.

[Brief explanation of the drawing]

The figure is a configuration diagram of an embodiment of an optical voltage measuring device according to the present invention. In the figure, 2-U, 2-V, 2-W-V-rut tube, 3-U
, 3-V, 3-W-4 body, 4-U, 4-V, 4-W, , intermediate electrode, 5...
...! 17J conversion switch, 6... Optical voltage sensor, 9-1... Optical fiber °8...
・Signal transmission device, 10... switch switching control device, 9
-2...Light 77 Iha-,. In addition, in the diagram, the same reference numerals indicate the same or equivalent parts.O Agent: Makoto Kuzuno Procedural amendment (voluntary). 5939 Mr. Commissioner of the Patent Office, Month, Day, Showa 1, Indication of Case, Patent Application No. 58-30558 2,
Title of the invention, Pressure device 3, Person making the amendment 5, Detailed description of the invention column 6 of the specification subject to amendment, Contents of the amendment (1) “The light Correct "voltage switch sochi" to "the optical voltage sensor". (2) On page 4, line 15 of the same page, change “density due to electrostatic density” to “
It should be corrected as "capacitance". (3) "Density partial pressure" on page 5, line 16 of the same page is replaced with "capacity partial pressure"
I am corrected.

Claims (1)

[Claims] Each of the three-phase bulk electric conductors is shielded with a shielded tube of a predetermined length, and each shielded tube is maintained at a ground potential, and an intermediate electrode insulated from other parts is arranged between each phase electric conductor and the shielded tube, A changeover switch is installed in the area surrounded by the three shielded tubes to sequentially switch and input the voltage of the intermediate electrode to one optical voltage sensor, and output the optical output of the optical voltage sensor to the outside via an optical fiber cable. Voltage measuring device 0 characterized in that the first chip taken out to the outside is guided to an external device that performs time-sharing processing in synchronization with the switching operation of the changeover switch.