Traditional current and voltage transformers are iron core transformers, which have inherent weaknesses and limitations, such as small range, low precision, large weight, and a certain degree of insecurity. In the late 20th century, a new type of sensor was developed to replace the traditional mutual inductance (1) current transformer: the new type of current transformer mainly includes AC coil and optical current sensor. The optical current sensor has basically the same advantages as the AC coil, but the main advantages are large dynamic range, good performance, small size, no open circuit problem, and low cost. The principle of

brown stay current sensor is to apply Faraday effect, that is, the polarization plane of a beam of linearly polarized light can be deflected under the action of an external magnetic field, and its rotation has a fixed function relationship with the magnetic field strength.

(2) Voltage sensor: The response characteristics of conventional voltage transformers are not good, and as the measured voltage increases, the volume of the voltage divider increases accordingly, and the response characteristics are worse.

country new photoelectric voltage sensor is an electro-optic crystal application pockels the principle of the electro-optic effect is made. The advantages of voltage sensors are: large dynamic range, good performance, fast response speed, can adapt to the requirements of electronic measurement, protection and control, and can be combined together, small size, light weight, easy installation, high reliability and electromagnetic compatibility Sex, good safety. Photoelectric voltage sensors have been widely used in the 21st century.