JPS62126356A - Optical transformer - Google Patents

Abstract

PURPOSE:To make it possible to independently detect voltage/current informations for protection and control by a common sensor part, by simultaneously passing light outputs from a plurality of light emitting sources different in wavelength and independently detecting the angle of rotation of a polarizing surface. CONSTITUTION:Lights emitted from two light emitting elements different in a light emitting wavelength are guided to a common polarizer 32 by a light insert device 311 through an optical fiber F1 and respectively individually receive the rotation of a plane of polarization surface by a common Faraday element 33 and, after the respective specific components thereof are taken out by a common analyser 34, said lights are guided to a light branching device 35 through a common optical fiber F2 to be applied to two light receiving elements 35A, 35B. If it is set that the light receiving element 35A receives only light with a wavelength lambda1 and the light receiving element 35B receives only light with a wavelength lambda2, current informations for protection and control can be independently obtained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a mixed current and voltage transformer for introducing power system information into a substation control and protection system, and in particular,
This article relates to photocurrent and photovoltage transformers that utilize optoelectronic technology.

[Background of the invention]

FIG. 4 shows an example of the arrangement of control and protection devices in a conventional substation and the connection relationship between them and the equipment.

In the figure, for example, nl for power transmission lines LA, Lm, Lc
In the case of the current transformer CT and the voltage transformer PT, their -order outputs are provided independently for the protection device and the control device, respectively. The biggest reason for this is that, in terms of Vl of the -current transformer, the dynamic ranges handled are significantly different for protection and control.

In other words, in the case of protection, of course, when the lineage is destroyed,
Even in the event of an abnormality, the passing current (in a super-transformation system, the value can be as high as 50V'2 x 2kA or 141V, including the transient DC component) must be guided to the protective relay device as a secondary output. On the other hand, in the case of control, the current should always be around the rated current or below (approximately 4000A or below in the case of ultra-high pressure systems).
This is because if a common CT is used for both, it is not possible to economically satisfy the required accuracy for both.

The second reason is to make the protective jumpers independent in terms of commercial use, so that a malfunction in one does not affect the other.

[Purpose of the invention]

The object of the present invention is to have a common sensor section for voltage and current information for protection and control, so that it can be detected independently and independently, and it can also detect lateral changes with a dynamic range suitable for both uses. <Our objective is to provide a voltage/current transformer that can be detected.

[Summary of the invention]

A method of realizing a current transformer using the interaction of light and a magnetic field is one that applies the Faraday effect, as shown in Section 21A. This method utilizes the fact that when a polarized wave is passed through, the direction of the ti light is rotated by an external magnetic field. Its configuration consists of a polarizer 32, a Faraday element 33, and an analyzer 34, and the principle of current detection is that the polarized light component of the direct current obtained from the light source 31 through the polarizer 32 is placed near the conductor. Since the magnetic field H is rotated in proportion to the magnitude of the magnetic field H when it passes through the Faraday element 33, the output intensity (the rotation angle θ component of the polarization plane as shown) is detected by the analyzer 34, and this is converted into an electric field. The current value is determined by processing the current value.

Figure 3 shows an example of this, gas insulated switchgear (GIS)
A Faraday element 33 is placed near the primary guide beam in 100.
, a polarizer 32, and an analyzer 34, a light emitting diode (LED) 31 is used as a light source, and the light is guided to the polarizer 32 through an optical fiber F1, and the light obtained by the analyzer 34 is transmitted through an optical fiber F2. A photodiode (PD), which is a light-receiving element,
35, where the output is converted into an electrical signal, converted into a digital signal by an analog-to-digital converter (AD) 36, and further converted into a digital signal.
This is an example in which data can be transmitted as digital data using a secondary parallel-to-serial conversion circuit (PS) 37.

In order to achieve the first objective by extending the configuration shown in FIG. It is necessary to provide a light emitting element and a light receiving element for each set, resulting in an expensive system.

[Embodiments of the invention]

In the present invention, the light emitted from two light emitting elements having different emission wavelengths (wavelength input 1 and wavelength input 2 light, respectively) is connected to a common optical fiber by an optical inserter 311, as shown in the typical embodiment shown in FIG. F1 is guided to a common polarizer 32, and the plane of polarization is individually rotated by a common Faraday element 33, which extracts each specific component by a common analyzer 34, and is connected to a common optical fiber F2. The light is guided through a light branch (f351) and given to two light receiving elements 35B, where one light receiving element 35A receives the light, and the other light receiving element 35B receives only the light. Ba,
Current for maintenance and control +′f! information can be acquired independently, each maintaining electrical independence.

1. The outputs of the two light-receiving elements obtained in this way are transferred to, for example, an AD converter 36A after the 35 light-receiving elements. If a 15-bit AD converter is used for each of the converters 368, the former can detect in units of digits even one signal of the maximum input with a dynamic range of 100V2kA (including transient DC components) for protection, and can achieve the required performance. Obtainable.

Moreover, if the latter is used for measurement and 12 pits of its 16-bit output are used, the artificial 1 = 100V2
12.5V'2kA was AD converted with 12 pits, 8 bit equivalent toner, ``'''', = 6.1v'2
A/2048digxtdig, and this value is 6 when sending a normal ultra-high HE system.
．． Even for a single person's rated current of 400 OA, there is an oval. 0OA
X100=0.15t, for measurement (for fl, IJ)
It can be seen that the required accuracy of ±0.3 inch or less can be sufficiently completed.

According to the optical transformer according to the present invention, it is possible to solve the problems caused by the difference in dynamic range, which was originally intended, while maintaining the independence of the protection and control functions.

In addition, although the example of the charging current transformer has been described above, the optical PT
Since the principle of can be realized by the configuration shown in FIG. 5, it is easy to understand that the same concept as that of the implementation column can be applied to the case of optical PT.

In FIG. 5, 31 is a light source using a light emitting element such as an LED, and 32 is a polarizer, which functions to extract only the linear side light component from the light emission components of the light source. On the primary side to be measured, both ends of the pressure 101 are applied to the Pockels element 40 which is an electric field-optical effect element, and when the light after passing through the tic field inward photon 32 is passed through the Pockels element 40. Since the light is polarized by an amount proportional to the magnitude of the electric field E due to the primary side voltage, only the phase difference component is extracted by the 174-wave plate 41, and this light is passed through the analyzer 34, so that only the effective component that is advantageous for measurement is extracted. It is designed to take out the .

Note that 38A and 38B in the figure are transmission lines.

[Brief explanation of drawings]

Figure 1 is a system diagram of an embodiment of the present invention, Figures 2 and 3 are explanatory diagrams of a method for realizing a current transformer using the interaction of light and magnetic fields, and Figure 4 is a conventional variation. FIG. 5 is an explanatory diagram of a method for realizing a voltage transformer using the interaction of light and magnetic fields.

Claims (1)

[Claims] 1. A magneto-optical effect element is placed near the primary conductor, and the polarization plane of the optical signal passing through the magneto-optical effect element rotates in proportion to the magnetic field generated by the current flowing through the primary conductor. In the optical transformer, optical outputs from a plurality of light emitting sources having different wavelengths are simultaneously passed through the single magneto-optical effect element, and rotation angles of optical signal polarization planes received by each of the optical signals can be individually detected. An optical transformer characterized by: