JPH03108673A - Light-transformer - Google Patents

Abstract

PURPOSE:To make it possible to measure not only a commercial frequency, but also a high-frequency component contained in a surge, by constructing a receiving part so that it detects a low-frequency component and the high-frequency component separately. CONSTITUTION:A light transformer comprises an electro-optical transducer 1 converting a voltage-current to be measured into a light signal, a wide-band amplifier 4 converting the light signal into an electric signal, a low-frequency amplifier 5 amplifying only a low-frequency component of signals therefrom, and a high-frequency amplifier 6 amplifying only a high-frequency component thereof. After an output light 3 of the device 1 is amplified by the amplifier 4, the low-frequency and high-frequency components are separated and a stationary voltage-current component and a temporary signal component such as a lighting-switching surge are distinguished from each other and measured. On the occasion, the amplifier 6 does not need to have so high a function as that for the low-frequency component. According to this constitution, an invasion from outside and a surge voltage generated inside can be measured by a compact arrangement for a long time, while a highly-precise function of measurement for a commercial frequency is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an optical transformer for measuring voltage or current of power transmission and transformation equipment.

(Conventional technology) Conventionally, circuit breakers and disconnectors have been used in power transmission and substations.

A gas-insulated switchgear is used, in which the grounding device, instrument transformer, lightning arrester, etc. are housed in a sealed metal container, and pressurized SF6 gas is filled in the container. Furthermore, due to improvements in various analysis and testing techniques using electronic computers, power transmission and substation equipment has become increasingly smaller and heavier, and the insulation technology that supports this has made remarkable progress.

By the way, various surge voltages are generated in power transmission and substations due to lightning strikes and opening/closing operations of circuit breakers, disconnectors, etc. used for system switching.

These surge voltages include frequency components from several hundred kilohertz to several tens of megahertz, which is much higher than commercial frequencies. When designing insulation for power transmission and substation equipment such as insulated switchgear and transformers, it is extremely important to quantitatively understand these surge voltages and collect the data necessary for insulation design in order to streamline insulation design.

However, in conventional designs, the insulation design is not necessarily based on rational considerations because the actual measurement data is limited. When actually measuring surge voltage, conventional methods require the installation of dedicated measuring equipment in power transmission and substation equipment, especially when long-term observation is required such as surge measurement.
There were problems with the reliability of the measuring instruments, and it was not always easy to achieve the objectives.

On the other hand, recent optical wave technology has led to the development of optical transformer technology that utilizes electro-optic effects such as the Pockels effect, Kerr effect, or Faraday effect, instead of the conventionally used wound transformer. It's here. Optical transformers inherently have better frequency response than wound transformers, are smaller and lighter, and are attracting attention as next-generation transformers because of their ease of signal processing.

(Problem to be solved by the invention) However, since current optical transformers require extremely high accuracy in measuring voltage and current, they are designed based on a design philosophy that ensures high accuracy at commercial frequencies. Technology was being developed. For this reason, it has the disadvantage that it is not very suitable for measuring surge voltages required for insulation design of power transmission and transformation equipment.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks and provide an optical transformer that can measure not only commercial frequencies but also high frequency components included in surges.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention converts voltage or current into an optical signal using an electro-optical conversion element and guides the signal to a receiving section via an optical path. , an optical transformer that converts an optical signal into an electrical signal in the receiving section and detects the voltage or current, characterized in that the receiving section is configured to be able to detect a low frequency component and a high frequency component separately. It is.

(Function) According to the present invention, while maintaining the function of highly accurate measurement of voltage or current as a transformer, it is possible to measure surge voltages that enter from outside of power transmission/transformation equipment or surge voltages that occur inside power transmission/transformation equipment for a long time. It becomes possible to measure over a period of time.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, 1 is an electro-optical conversion element that converts a voltage or current signal to be measured into an optical signal, and 2 is an electro-optical conversion element 1.
3 is the output light from the electro-optical conversion element 1, 4 is the incident light on the
is a high-bandwidth amplifier for converting optical signals to electrical signals,
5 is a low frequency amplifier that amplifies only the low frequency component of the signal from the high band amplifier 4, and 6 is a high frequency amplifier that amplifies only the high frequency component of the signal from the high band amplifier 4.

Next, the operation of this embodiment will be explained.

The response characteristics of the electro-optical conversion element 1 are generally much better than those of an amplifier used for amplifying electrical signals. In such a case, the output light 3 of the electro-optical conversion element 1 contains various information ranging from low frequency components to high frequency components. After the signal of this output light 3 is once amplified by a high-band amplifier 4, it is separated into a low frequency component and a high frequency component, and is divided into a steady voltage or current component and a temporary signal component such as a lightning surge or a switching surge. and be measured separately. In this case, since the low frequency amplifier 5 is required to be highly accurate, it is necessary to configure a measurement circuit commensurate with this. On the other hand, the high frequency amplifier 6, which deals with high frequency components, does not require high precision for low frequency components, so the circuit configuration is simple and the cost is reduced accordingly.

As described above, according to this embodiment, while maintaining the function as a transformer of highly accurate measurement of voltage or current for commercial frequencies, it is possible to prevent surge voltages that enter from the outside of power transmission and substation equipment, or that occur internally. Surge voltage can be measured compactly and over a long period of time.

FIG. 2 is a block diagram of another embodiment of the present invention.

In the figure, the voltage or current to be measured is measured by an electro-optical conversion element 11 having high accuracy for low frequency components and an electro-optical conversion element 1 having high accuracy for high frequency components.
5 is applied.

Reference numeral 12 denotes light incident on the electro-optical conversion element 11, and the signal of the output light 13 is amplified by a low frequency amplifier 14, and a steady voltage component or current component is measured. Further, 16 is the incident light to the electro-optical conversion element 15, and this output light 17
The signal is amplified by a high frequency amplifier 18, and a temporary high frequency voltage component or current component such as a lightning surge or a switching surge is measured.

In this way, in this embodiment, a transformer is configured for each of the electro-optic conversion elements 11 and 15, so that the electro-optic effect of the electro-optic conversion element can be applied to each required frequency band. Since it becomes possible to select them together, it becomes possible to configure an optical transformer with higher precision.

Although this example shows an example using two electro-optic conversion elements, it is possible to create an optical transformer with even higher precision by combining multiple electro-optic conversion elements with different frequency characteristics as necessary. Needless to say, it can be configured.

[Effects of the Invention] As explained above, according to the present invention, in addition to the function as a transformer of highly accurate measurement of voltage or current for commercial frequencies, surge voltages and It is possible to measure internally generated surge voltages with high precision, compactly, and over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of another embodiment of the present invention. 1, 11. 15...Electro-optical conversion element 2.12.
16...Incoming light 3.13.17...Output light 4...High band amplifier 5.14...Low frequency amplifier 6.18...High frequency amplifier (11733) Agent Patent attorney Sho Inomata Akira (1 other person)

Claims (1)

[Claims] In the optical transformer, the voltage or current is converted into an optical signal by an electro-optical conversion element and guided to a receiving section via an optical path, and the optical signal is converted into an electrical signal in the receiving section and the voltage or current is detected. An optical transformer characterized in that a receiving section is configured so that low frequency components and high frequency components can be detected separately.