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Anti-pollution flashover coating is the most effective method to control pollution flashover in China
Issuing time: 2018-04-16 10:39
What are the anti-pollution flashover methods used in China at this stage? So what are the most effective methods now? Aiming at the current anti-pollution flashover methods used in the national power grid and internationally, review the development history of anti-pollution flashover work in China's power system and analyze The status quo of anti-pollution flashover and related technical policies, put forward the current and feasible anti-pollution flashover technologies and anti-pollution flashover policies from foreign countries that are not completely suitable for China's national conditions, and it is necessary to develop a "one step in place" in line with national conditions. Anti-fouling flash technology policy; it is proposed that anti-fouling flash coatings will become increasingly important anti-fouling flash products for power equipment, especially transformer equipment in a long period of time in the future. Performance, so that it is upgraded from a temporary and remedial product-RTV to a formal and durable product-PRTV.
1 Historical review and status quo analysis of anti-pollution flashovers in power systems
1.1 Brief History of Anti-pollution Flash
(1) In the 1950s, pollution flashes began to appear in power equipment in relatively developed areas such as China's coastal regions.
(2) Before the 1980s, the main insulation of China's power equipment was porcelain insulators. Among them, the external insulation of transformer equipment includes disc-shaped suspension insulators, pillar insulators, porcelain sleeves and bushings. Except for the large number of suspension porcelains used in lines, In addition to insulators, a small amount of toughened glass insulators are used. Both porcelain insulators and glass insulators are inorganic materials. The biggest feature is that the materials have super aging resistance and the service life is up to 50 years. In addition, silicone oil and paraffin wax are also used in small amounts as anti-pollution flash measures.
(3) Since the 1980s, with the development of China's economy, environmental pollution has become increasingly serious. The zero-level and first-level external insulation configurations that have been used extensively in power equipment in the past have been difficult to meet the requirements for anti-pollution flashover. Cleaning once a year has become a pollution-flash suppression Major technology policies. While strengthening the cleaning, the line began to be adjusted on a small scale (including increasing the string length and replacing the insulator with a large creepage distance); due to the inconvenience of replacing the equipment in the substation, the use of silicone oil and ground wax has a significant anti-pollution flashover effect, but the validity period is too short. 3-6 months, with severe adhesion and fouling, difficult to clean.
(4) In the mid-to-late 1980s, the line began trialing synthetic insulators (Beijing Power Supply Company and Tianjin Electric Power Company tried a small amount of 35kV synthetic insulators in 1986); substations began to use RTV coatings.
(5) In the 1990s, especially in the mid-to-late 1990s, with the continuous improvement of technology, synthetic insulators have been used in large quantities as formal external insulation products popular with design, infrastructure and operation units, such as Tianjin Electric Power More than 85% of the company's line straight strings are synthetic insulators. The RTV coating only emphasizes the single performance of anti-pollution flashover, and its comprehensive performance is generally low, especially the short period of validity (3-5 years). Therefore, it has been used as a remedial and temporary anti-fouling measure for transformer equipment, which is difficult to be used by electricity. Accepted by the design and infrastructure sectors, this phenomenon continues to this day.
(6) In recent years, environmental pollution has not improved (environmental pollution in large and medium-sized cities has been curbed, and the majority of small and medium-sized cities and rural areas have not improved or become worse), and the increasing number of transmission and transformation equipment and "redundancy and efficiency" The contradiction caused by this has led to the increasingly difficult implementation of the anti-pollution flashover measures of “cleaning once a year”. The maintenance and cleaning work that only took a few months in the past year now needs to be completed across the whole year. For this reason, in 2001, Guodian Corporation proposed a technical policy of “Configuring the external insulation of equipment according to saturated salt density”. At present, this work is under intense preparation and implementation.