The interaction between salt density and gray density

The salt density and ash density on the surface of the insulator are the basis for judging the pollution degree of the insulator, and its value also represents the pollution degree of the local external insulation equipment.

According to the proportion of soluble matter (called salt) and insoluble matter (called ash) in the pollution, the types of pollution are divided into A and B categories.

Class A: Solid contaminants containing insoluble matter are attached to the insulating surface, and the contaminants conduct electricity when wet. Such contaminants can be characterized by measuring equivalent salt density and gray density.

Class B: The liquid electrolyte adheres to the insulating surface and contains a small amount of insolubles. Such contaminants can be characterized by measuring equivalent salt density and ash density.

Type A pollution is common in inland, desert or industrial pollution areas. The salt pollution layer formed on the surface of insulators in coastal areas can also be regarded as Class A pollution under the influence of dew, fog or drizzle.

Type B pollution mainly exists in coastal areas, where sea breezes carry salt mist and settle directly on the surface of the insulator. Chemical mists emitted by chemical companies and heavy fog and drizzle with high salt content caused by severe atmospheric pollution can also be classified as such.

On-site pollution measurement: After the insulator has been contaminated for 3 to 5 years, the surface equivalent salt density and gray density are measured. The on-site pollution can be measured on the live electrified reference disc-type suspension insulator, or on the uncharged reference disc-type insulator suspended near the running insulator string. The ratio of the charged measurement value to the uncharged measurement value (that is, the charging coefficient) should be determined according to the actual measurement results in various places. (YM3200 direct-reading salt density meter supports the setting of charge coefficient)

Note: Grade a—very light; grade b—light; grade c—medium; grade d—heavy; grade e—very heavy. The pollution degree indicated by this letter does not correspond to the pollution degree represented by numbers in GB / T16434-1996.