Product Description and Usage Instructions:

P, PQ High-Voltage Line Pin-Type Porcelain Insulators

I. Overview

Needle-type insulators are an older type of insulator used in high-voltage transmission and distribution lines. Due to their simple manufacturing, low cost, easy installation, and ability to reduce the height of poles (as they are installed vertically with the grounding part at the bottom), they are widely employed in overhead power lines with a rated voltage of 6～35kV and a frequency of 100Hz in standard and polluted areas for three-phase power systems, serving as insulation and support for conductors.

The needle-type insulator is composed of an insulating element and a steel base, which is a rigid insulator that rigidly mounts the insulating element onto the support structure by means of a steel base fixed within the insulator. The insulator can be made up of a single piece or multiple insulating elements connected together. The insulating elements of the porcelain insulator are porcelain pieces, typically glazed in brown or white. The fixation of the porcelain pieces and the base can be separable or permanent (as in needle-type insulators with adhesive feet).

Insulators are categorized by structure into two types: glue-mounted and zinc-threaded connection. The glue-mounted type connects the porcelain piece directly to the base with cement, featuring a deep groove in the porcelain section where the steel base is inserted to prevent loosening, and an elastic pad is placed between the steel base and porcelain piece. The zinc-threaded connection type involves first cementing a zinc threaded sleeve into the porcelain inner hole, and then connecting the sleeve to the steel base via the threads. The zinc threaded sleeve serves as a shock absorber and facilitates the replacement of the porcelain piece. There are also types that use mechanical connections through porcelain threads.

The old model needle-shaped porcelain insulators specified in the GB1000-1981 standard are divided into five grades according to rated voltage: 6, 10, 15, 20, and 35 kV. Each grade is further divided into two specifications based on the steel foot type: iron pole straight foot and wood pole straight foot.

The new model needle-type porcelain insulators specified in GB/T1000.2-1988 standard have a rated voltage of 10kV, and are categorized into three types according to applicable environmental conditions: Standard Type, Reinforced Insulation Type 1 (Medium Pollution), and Reinforced Insulation Type 2 (Heavy Pollution).

To reduce radio interference, edge glaze insulators are provided for the upper half of the conductive glaze above the side slots, with models containing the letter "B".