An Optical Sensor Realizing Arc Flash Detection in Switchgear

Abstract

The invention discloses an optical sensor capable of effectively detecting produced electric arc light and converting the electric arc light into an electric signal to be output when an outgoing wire or a bus of a switch cabinet has a short-circuit fault. The optical sensor comprises a light acquisition lens, a photoelectric converter and a plastic optical fiber, wherein two ends of the plastic optical fiber are provided with ST connectors, and the plastic optical fiber is connected with the light acquisition lens and the photoelectric converter through the ST connectors. Due to the fact that the light acquisition lens is a passive device, the light acquisition lens is connected with the active photovoltaic conversion portion through the plastic optical fiber, and a primary device of the switch cabinet is not influenced. The light acquisition lens only acquires light information of specific wave bands in arc light and can effectively filter interference of other light sources. An electrical signal only existing at the photovoltaic conversion portion of the sensor, the rest is light signals, and electromagnetic interference produced during actions of the switch cabinet can be effectively avoided. By adopting anti-static design achieved by a transient diode, the device reliability is improved, and the optical sensor can adapt to various assembling and usage environments.

Description

technical field [0001] The invention relates to the field of optical sensing, in particular to an optical sensor applied to arc flash monitoring of switch cabinets in electric power systems. Background technique [0002] Medium and low voltage switchgears are suitable for power transmission, distribution and power conversion in power plants, petroleum, chemical, metallurgy, textile, high-rise buildings and other industries. In recent years, there have been frequent accidents in medium and low-voltage switchgear across the country. The reason is that when a single-phase ground fault occurs in the outgoing line or busbar, due to the large capacitive current at the ground point, the arc at the ground point cannot be completely extinguished, resulting in repeated re-ignition of the arc. ; and because of the arc resistance, the short-circuit current often does not reach the set value of the over-current speed and cannot quickly act to cut off the fault, while the insulation l...

AI Technical Summary

Problems solved by technology

[0003] Power grid equipment damage and power outage accidents caused by medium voltage switchgear arc flash not only cause considerable economic losses, but also seriously affect the safe and stable operation of the power grid, thus directly threatening the normal operation of substations and the safety of operating personnel

Images