The insulator has an ice flashover failure. To reduce the calculation error of the equivalent icing thickness of transmission lines due to the insufficient number of sensors, a new online monitoring device for wire icing based on 3 sets of force sensors and inclination sensors was designed. The device integrates multiple monitoring functions such as micro-meteorology, wire temperature, distributed multi-rod tension, and images. The study found that the main reason for the ice flash of insulators is that the ice bridging the insulation on the string skirt. The high conductivity of melting ice water causes the ice flash voltage to be too low. A water curtain that blocks the melted ice water with high conductivity from forming a flashover channel. It is a basic measure to improve the ice-coated insulation and the flashover voltage of the ice string.

Nonlinear electric conductance of reinforced insulation can homogenize electric field distribution and suppress local electric field distortion inside high-voltage direct current cable accessories. To achieve a significant nonlinear electric conductance in ethylene–propylene–diene misch–polymere (EPDM) used for reinforced insulation of cable accessories, the inorganic micron crystal powder of calcium copper titanate (CCTO) is synthesized by the sol–gel method, which is filled into EPDM to prepare 5∼15 wt% CCTO/EPDM composites by melting blend and hot-press molding methods. Microscopic structure, electric conductivity, direct current (DC) dielectric breakdown strength, and charge trap characteristics of CCTO/EPDM composites are tested to reveal the underlying derivation of electric conduction nonlinearity. Scanning electron microscopy and X-ray diffraction (XRD) demonstrate that CCTO micron fillers are uniformly dispersed in the EPDM matrix. Dielectric breakdown strength of CCTO/EPDM composites gradually decreases with the increase in CCTO content while persisting qualified for electrical insulation of DC cable accessories. CCTO crystal macron fillers introduce shallower charge traps than the intrinsic charge traps derived from the structural defect EPDM matrix, which initiates the percolating conductive channels between charge traps under high electric fields, accounting for the significant nonlinearity in the profile of electric current density versus electric field strength. Finite-element simulations and analyses on the electrostatic field in DC cable terminals prove that employing 15 wt% CCTO/EPDM composite as reinforced insulation can efficiently homogenize the electric field at the interface between the main insulation and accessory insulation of power cables, which is of great interest to develop insulation materials used for DC cable accessories in severe environments.

Background: The styloid process (SP), stylohyoid ligament and lesser horn of hyoid bone together form the stylohyoid chain. Differences in the ossification degree and the connection sites of each segment of the stylohyoid chain on both sides lead to variations in the length, orientation, thickness, and straightness of SP. The incidence of elongation of the SP, known as styloid process syndrome (SPS), is around 4%, with only 4% of patients showing elongation show symptoms. Computed tomography (CT) remains the firstchoice auxiliary examination for diagnosing SPS, but its performance can be affected by a variety of factors.Ultrasound can reveal the parapharyngeal space and adjacent structures, which offer high consistency with CT findings. Here, we investigated the ultrasonographic features of the SP and its adjacent structures in normal adults and assessed the clinical utility of ultrasound assessment for SP-related diseases.Methods: With the ramus of mandible, mastoid process, SP, and salivary gland as the anatomical landmarks, ultrasonography was conducted on the parapharyngeal space in 78 healthy adults. The scans were performed along the oblique coronal section of the ramus and the cross-sectional plane between the mastoid process and ramus to visualize the SP and its adjacent structures. The SP length, the shortest distance from the SP tip to the outer edge of tonsil (SP-tonsil distance), and the distance from SP to the internal carotid artery (SP-ICA distance) were measured.Results: SP and its adjacent structures were successfully visualized on ultrasonography in all 78 subjects.The measured SP length was 2.65±0.48 cm. The SP-tonsil distance was 1.95±0.50 cm. The SP-ICA distance was 0.509±0.231 cm. The SP length and SP-tonsil distance measured by ultrasound were not significantly different from those measured by CT (P=0.071, P=0.053). Furthermore, the SP length and SP-tonsil distance measured by ultrasound were positively correlated with CT measurements (r=0.917, P=0.071; r=0.978, P=0.053, respectively). SP-tonsil distance was negatively correlated with SP length and SP inward deflection angle.Conclusions: Ultrasound can accurately reveal the shape and size of SP and its adjacent structures and thus will be helpful for the diagnosis of SP-related diseases.

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