Electric spark is a form of electric arc, which is an electronic component. The striking spark is not an electric arc, it is a spark, it is a particle of a high-temperature substance that is hit. The two are essentially different. A certain voltage, when he ionizes the air, vacuum or other substances between the electrodes, it is released in the form of sparks. The stone and the stone rub against each other to generate energy, and the release becomes an electric spark. The high voltage breaks down the insulation. The high voltage of material discharge is generally based on electromagnetic induction. The energy difference may be generated during friction. The excess energy generates high temperature and is released in the form of light and heat.
With the continuous expansion of the power grid scale and the continuous improvement of power load requirements, the damage and failure of various types of high-voltage equipment used in the power system are also increasing, and the requirements for preventive maintenance are also increasing. Equipment such as power transmission and supply lines and substation power distribution work in an atmospheric environment. In some cases, structural defects or surface partial discharges occur as the insulation performance decreases. During the corona and surface partial discharge processes, the corona and discharge parts will be A large amount of ultraviolet radiation is radiated, so that the generation and enhancement of corona and surface partial discharge can be used to indirectly evaluate the insulation status of operating equipment and find defects in insulation equipment in time.
Because of the various methods that can be used for the discharge process for diagnostic purposes, the optical method has the best sensitivity, resolution and anti-interference ability. The gallium-core photoelectric ultraviolet sensor is used to develop arc ultraviolet detection, that is, a high-sensitivity ultraviolet sensor and radiation receiver are used to record the ultraviolet radiated during corona and surface discharge, and then process and analyze to achieve the purpose of evaluating the condition of the equipment. Prevention and reduction of major losses caused by equipment failures have great economic benefits.
At present, corona discharge detection on transmission lines mainly includes: manual inspection detection, pulse current detection, infrared detection, ultrasonic corona detection, and ultraviolet detection. Because the target of corona discharge is small, the signal is weak, and many transmission lines are installed outdoors with relatively poor natural conditions, manual inspections are not only time-consuming and laborious, but also have poor detection results; pulse current detection is not suitable for ultra-high voltage detection. Moreover, the volume of the instrument is large; infrared detection is greatly affected by sunlight, the false detection rate is high, and the response speed is slow. When infrared can be detected, the line is often heated, which is a later detection and cannot meet the current requirements of power transmission and transformation; ultrasonic corona detection It is also difficult to achieve the desired effect outdoors. The more effective corona discharge monitoring of high-voltage power grid is ultraviolet monitoring.
The existing UV detection equipment is mainly UV phototubes and semiconductor UV detectors. The representative product of UV photoelectricity is R2868. However, when this product detects ultraviolet light in the UVC band, the phototube is in the open or off state. It can reflect the intensity of the corona in real time. At this stage, semiconductor-type UV detectors are mainly UV-Arc and UV-Arc imported from Sglux in Germany. Generally, the current generated by the general ultraviolet sensor will be very low when detecting weak ultraviolet rays. Therefore, the sensor must be a low dark current sensor based on SiC material. After high magnification, the effect of dark current on the output value will be reduced to lowest. At the same time, due to the increased magnification ratio, the sensor material is generally not completely insensitive to ultraviolet rays in the UVA and UVB bands. The A and B band ultraviolet rays in the sun are not negligible compared to the C band ultraviolet rays in the corona. In a circuit with high magnification and multiple speeds, the errors caused by the A and B bands under sunlight will completely cover the C band, so the sensor must be added with a filter during use. German Sglux ultraviolet sensor-UV-Arc comes with a filter that suppresses the A and B bands of sunlight, and its metal casing has high electromagnetic compatibility. The sensor body is completely waterproof, mainly used for pantograph arc monitoring, high-voltage wire arc monitoring, the monitoring distance needs to be determined according to the arc intensity
