Image Characteristic Extraction of Ice-Covered Outdoor Insulator for Monitoring Icing Degree

Abstract

Serious ice accretion will cause structural problems and ice flashover accidents, which result in outdoor insulator string operating problems in winter conditions. Previous investigations have revealed that the thicker and longer insulators are covered with ice, the icing degree becomes worse and icing accident probability increases. Therefore, an image processing method was proposed to extract the characteristics of the icicle length and Rg (ratio of the air gap length to the insulator length) of ice-covered insulators for monitoring the operation of iced outdoor insulator strings. The tests were conducted at the artificial climate room of CIGELE Laboratories recommended by IEEE Standard 1783/2009. The surface phenomena of the insulator during the ice accretion process were recorded by using a high-speed video camera. In the view of the ice in the background of the picture of fuzzy features and high image noise, a direct equalization algorithm is used to enhance the grayscale iced image contrast. The median filtering method is conducted for reducing image noise and sharpening the image edge. The maximum entropy threshold segmentation algorithm is put forward to extract the insulators and its surface ice from the background. Then, the modified Canny operator edge detection algorithm is selected to trace the boundaries of objects through the extraction of information about attributes of the endpoints of edges. After we obtained the improved Canny edge detection image for both of the ice-covered insulators and non-iced insulators, the icing thickness can be obtained by calculating the difference between the edge of the non-iced insulators image and the edge of the iced insulator image. Besides, in order to identify the icing degree of the insulators more accurately, this paper determines the location of icicles by using the region growth method. After that, the icicle length and Rg can be obtained to monitor the icing degree of the insulator. It will be helpful to improve the ability to judge the accident risk of insulators in power systems.

Electric Field Distribution and AC Breakdown Characteristics of Polluted Novel Lightning Protection Insulator under Icing Conditions

“…They are negative power function, quadratic function, negative power function with the constant term, and piecewise function. The functional form is shown in Equations ( 5)- (8).…”

“…Large-scale power outages caused by pollution-induced flashover accidents might harm social-economic growth [4][5][6]. In addition, as a unique form of pollution, the harm of insulator surface icing to the power systems is prominent [7][8][9].…”

Outdoor Insulation and Gas-Insulated Switchgears

“…Liu et al [46] proposed a method to monitor of the icing degree of an insulator during icing accretion. Two algorithms (direct equalization and median filter methods) have been used to reduce the noise and enhance the contrast of the images obtained in simulated laboratory conditions.…”

Physical De-Icing Techniques for Wind Turbine Blades

“…Ice accumulation on different aerodynamic structures and industrial constrictions is a significant problem for their protection and operation. The lines transmission can have huge additional static loading due to massive ice accumulation on the cables or their insulators doing power blackouts [4]. Larger fragments of the accreted ice can fall off with a potential danger of grim or even fatalities, involving pedestrians around the building, traffic crossing the bridge, or wind turbines placed close to highways.…”

“…3 installation of vibration mechanisms in characteristic areas of the blade for ice dumping. 4 the share of the power consumption of the protection system from the rated power of the wind generator.…”