Optical voltage measuring apparatus

Abstract

An optical voltage measuring apparatus includes at least a light source, an optical branching device, a polarizer, a phase modulator, a transmission fiber, a Faraday rotator that turns the polarized wave of emitted light from the fiber, an electro-optic element that applies refraction index change by a Pockels effect to the turned light, a reflector mirror, and a detector. When the temperature coefficient of the sensitivity of the electro-optic element is positive, incident polarized light orientation of the Faraday rotator to the electro-optic element is set so as to be coaxial with the axis of birefringence that appears by the Pockels effect at the lowest temperature in a service temperature range. When the temperature coefficient of the sensitivity of the electro-optic element is negative, the same setting is made at the highest temperature in the service temperature range.

Description

technical field [0001] Embodiments of the present invention relate to an optical voltage measurement device for measuring voltage of transmission and distribution lines, distribution voltage of electric equipment, and the like. Background technique [0002] Figure 7 A configuration example of a conventional optical voltage measuring device is shown in . [0003] This optical voltage measurement device 100 includes a sensor unit 101 , a light emitting unit 102 , a light receiving unit 103 , and signal processing circuit units (not shown) on the light emitting side and the light receiving side. [0004] The sensor unit 101 includes a polarizer 13 , a quarter-wave plate 35 (hereinafter also referred to as “λ / 4 plate”), an electro-optic element 31 , and an analyzer 52 arranged sequentially on the same optical axis from the light incident side. [0005] In addition, the light emitting unit 102 includes an E / O circuit including a light emitting element such as an LED (Light Emit...

AI Technical Summary

Problems solved by technology

[0013] However, the optical voltage measuring device 100 is a method of measuring the applied voltage Vm by calculating the degree of modulation of the light quantity, so there is a problem in that it cannot measure the DC voltage essentially.

In addition, sensitivity errors and phase errors will also occur due to environmental changes such as temperature, but this is different from the case of current measuring devices, so they become errors when measuring power and impedance, deteriorating measurement accuracy

In addition, since a voltage divider is required in the measurement, there is also the problem that the measurement accuracy and response speed are limited by the voltage divider

[0014] In addition, in the optical voltmeter aiming at eliminating the voltage divider, light propagation in gas needs to be long-distance, or many light sources and optical systems are required, which poses problems in terms of accuracy and reliability

[0015] On the other hand, a method of measuring voltage using the amount of light itself as a signal has also been considered, but in reality, a change in the sensitivity of the detector or a change in the transmittance of the optical element directly leads to an error, so it is difficult to obtain the necessary accuracy

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