What is polymer line post insulator


1. Brief introduction of polymer line post insulators.

Polymer line post insulator (also called composite line post insulator, polymeric line post insulator) consisting of a load-bearing cylindrical insulating solid core, a housing and end fittings attached to the insulating core. It is intended to be subjected to cantilever, tensile and compressive loads. The polymer line post insulators are often used in braced structures whose geometry varies from line to line.

Core of a polymer line post insulator is the internal insulating part of the insulator which is designed to ensure the mechanical characteristics. The core usually consists of either fibers (e.g. glass) which are positioned in a resin-based matrix or a homogeneous insulating material (e.g. porcelain or resin).

force on post insulator

2. Type of polymer line post insulators

The polymer line post insulators are usually for a. c. systems with a nominal voltage greater than 1 000 V. Usually according to how the insulator are installed, the polymer line post insulators are divided into 2 group of horizontal post insulators and vertical post insulators. And pin type insulators belong to vertical ones. Refer to the following figures for polymer line post insulators.

3. Main characters of polymer line post insulators

Polymer line post insulators are in an atmospheric space and exposed to pollution, rain, and other natural phenomena make them at risk of being damaged due to punctures. It nearly has no risk of flashover to working at heavy pollution area, when comparing with porcelain post insulators. 

4.Tests for polymer post insulators

The tests for polymer line post insulators are described in IEC 61952. And tests are divided into 4 groups:

4.1 Design tests

These tests are intended to verify the suitability of the design, materials and method of manufacture (technology). A composite line post insulator design is defined by the following elements:

  • materials of the core, housing and their manufacturing method,
  • material of the end fittings, their design and method of attachment (excluding the coupling),
  • layer thickness of the housing over the core (including a sheath where used),
  • diameter of the core.

4.2 Type tests 

These tests are intended to verify the main characteristics of a polymer line post insulator which depend mainly on its shape and size. Type tests shall be applied to polymer insulators, the class of which has passed the design tests.3.3 Sample testsThe sample tests are for the purpose of verifying other characteristics of polymer insulators, including those which depend on the quality of manufacture and on the materials used. They are made on insulators taken at random from lots offered for acceptance.

4.3 Routine tests

These tests are intended to eliminate polymer line post insulators with manufacturing defects. They shall be made on every polymer line post insulator offered for acceptance.

5. Main manufacturer of post insulators

  • Xiangyang Guowang Composite Insulators Co., Ltd.
  • Maclean Power System
  • Lapp insulator