This insulator, designed for the 25kV/27.5kV voltage grade in railway applications, serves to isolate the electrical conductors from the support framework during the operation of the railway power supply. It not only accomplishes the fundamental insulation task but also complies with the special technical requirements of the railway. For example, it must withstand the continuous vibrations from passing trains and maintain stable performance under the complex electromagnetic environment along the railway line.
Distinguishing it from the single-insulated counterpart, there are two main differences. Firstly, in the bottom silicon rubber section, a wire groove is reserved between the second last and the last umbrella skirts. After proper installation, a wire can be inserted into this groove. In case of a discharge, the wire in the groove can short-circuit the bottom of the insulator, redirecting the current and protecting the insulator from total breakdown. Secondly, it has a higher structure height compared to the 25kV/27.5kV Single-insulated Suspension Composite Insulator for Railways.
Although the Deadend Insulators of transmission line towers are similar in appearance to the Suspension Insulators in the electrified railway catenary system, there are significant differences between them in the manufacturing process of core rods, forging process of fittings, the number and method of crimping procedures for fittings and core rods, as well as the quality inspection regulations for semi-finished and finished products.
When trains pass at high speeds, the strong wind and high-frequency vibrations impact the contact wire of the catenary, and the huge tensile load will be transmitted to the Suspension Insulators directly connected to the wire. Moreover, such impacts occur many times a day or even every hour. Therefore, the relevant standard documents for Suspension Insulators for Railway have put forward more stringent requirements for the Specified Mechanical Load (SML) of such products. As we all know, according to ANSI C29.13, the SML performance index of 28kV Deadend Insulators only needs to be ≥70kN. However, according to the Chinese railway industry standard TB/T 3199.2 - 2018, the SML performance index of 27.5kV Suspension Insulators used in the high-speed railway catenary is required to be ≥200kN. That is to say, the SML performance index of Deadend Insulators for power grids is only 35% of that of Suspension Insulators for Railway with the same voltage level.
JD Electric has a sophisticated team of engineers, which has designed and manufactured insulator products for electrified railways in many countries and has ensured their safe operation in railway systems of various countries for many years. China Railway Construction Corporation, China Railway Group Limited, China State Railway Group Co., Ltd., and the China Academy of Railway Sciences regularly send experts to JD Electric for technical exchanges, to improve the processes of existing products, and to conduct discussions on demand analysis and research and development planning for new products.
Standards:
IEC 62621-2011; TB/T 3199.2-2018; Q/CR 549-2016
Specifications:
Application:
It is mainly used on the support structures of the electrified railway contact network. Its primary role is to support the electrical conductors and maintain excellent electrical insulation, which is crucial for the stable power supply and the safe running of trains.
Features:
● High Reliability:
Meeting the strict requirements of the railway sector, it can operate stably for an extended period, minimizing the need for maintenance and ensuring the uninterrupted progress of railway operations.
● Railway-specific Design:
Its structure and material selection are optimized according to the characteristics of the railway environment, making it more suitable for handling the challenges of railway operations than general power system insulators.
● Improved Anti-pollution Ability:
Considering the various pollutants along the railway, it has an effective anti-pollution design to maintain its insulation performance, thereby ensuring the safety of the railway power supply system.
● Excellent Vibration Tolerance:
With high resistance to vibration, it can effectively cope with the vibrations caused by passing trains and preserve its position and insulation function on the support structures.
