Lines and power plants, substations, filth level: in accordance with the actual measurement of the filth salt density value mg/cm2, set out the filth level. Filth level is divided into: 0, Ⅰ, Ⅱ, Ⅲ, Ⅳ level, *** five levels.
Do a good job of preventing pollution flash accident groundwork, we must adhere to the salt density measurement, and according to the environmental protection and meteorological data and operating experience, the classification of filth level and draw the system to make a map of the sewage area.
Salt density measurement method is to use a certain amount of distilled water, insulators or electrical equipment porcelain parts on the surface of the dirt cleaned down, and measure its electrical conductivity, and then an equal amount of distilled water to produce the same electrical conductivity of the amount of sodium chloride salt, as the equivalent amount of salt, then
Equivalent density of salt = W / A (4-1)
In the formula W - equivalent salt, mg;
A - insulator surface area, cm2.
(a) the level of filth in the substation level
In accordance with the severity of the filth can be divided into a number of level of filth in the substation. Grade.
Based on the natural environmental conditions of filth, the International Electrotechnical Commission will be divided into four levels of filth.
(1) light: mainly the absence of industry, the installation of heating equipment in the housing density of small areas; industrial or housing density is small, but often windy and (or) rainy areas; agricultural areas; mountainous areas. All of these areas are at least 10-20km from the sea and do not suffer directly from the action of the sea breeze.
(2) Medium: industrial areas that do not produce particularly polluting soot and/or areas with a medium density of houses with heating equipment; areas with a high density of houses and/or industries but with frequent wind and/or rain; areas that are subject to the action of the sea breeze but are not too close to the coast (at least a few kilometers apart).
(3) Heavy: areas of high industrial density and urban areas with a high density of pollution-producing heating equipment; areas close to the coast or in any case exposed to fairly strong sea breezes.
(4) very heavy: can be subjected to conductive dust and can produce particularly thick conductive deposits of industrial soot, the range of moderate; very close to the coast and will be subject to sea spray or will be subject to a strong polluting sea breeze, the range of moderate; long periods of no rain by the sand and salt sand and strong winds, and often condensed dew in the region and desert areas.
China's national standards, compared with only one more level 0, for no obvious dirt areas.
(B) high-voltage overhead lines of the filth level
High-pressure overhead lines of the filth level classification standards, the following filth level:
(1) 0 level for the atmosphere is clean and away from the coast of more than 50km of the region, the salt density, for strong electrolytes 0 ~ 0.03mg/cm2, for weak electrolytes 0 ~ 0.06mg/cm2.
(2) 1 level for the atmosphere is clean and away from the coast of more than 50km of the region, its salt density, for strong electrolytes 0 ~ 0.03mg/cm2, for weak electrolytes 0 ~ 0.06mg/cm2.
(2) 1 level for the atmosphere is mildly polluted areas or moderately polluted areas of the atmosphere, including saline areas, furnace smoke fouling areas, and 10 to 50km from the coast. In the flash season, dry and less fog (including drizzle) or more rain, the salt density of 0.03-0.05mg/cm2.
(3) Level 2 for the moderately polluted areas of the atmosphere, including saline areas, furnace smoke dirty areas, and from the coast of the 2-10km area, in the flash season, humid and foggy (including drizzle) but less rain, the salt density of 0.05-0.10mg/cm2.
(4) Level 3 is a seriously polluted area, including areas with heavy fog due to atmospheric pollution, areas 1 to 3km from the coast, and heavily saline areas near salt farms, with a salt density of 0.10-0.25mg/cm2.
(5) Level 4 is a particularly seriously polluted area, including areas attacked by heavy salt fog, and areas within 1km from the coast, with a salt density greater than 0.25mg/cm2.
(5) Level 4 is a particularly seriously polluted area, including areas attacked by heavy salt fog, and areas within 1km from the coast, with a salt density greater than 0.25mg/cm2. Its salt density is greater than 0.25mg/km.
Three, the design of the anti-pollution measures
Design, should be in the dirt area map and the distribution of the source of dirt on the basis of determining the configuration of the external insulation of the power plant, substation, overhead lines.
In the substation design, the site should be located as far away as possible from the various sources of pollution, especially chemical plants, fertilizer plants and metallurgical plants, etc., the site should be in a variety of sources of pollution in the prevailing wind direction of the upwind side. Insulators and electrical equipment outer insulation creepage ratio distance selection, should be based on the nature and severity of the source of pollution in the substation to determine the level of filth. The minimum creepage distance of the outer insulation of electrical equipment is shown in Table 4-10. For seriously dirty areas can be used in the house power distribution or gas-insulated metal-enclosed appliances; for indoor power distribution in humid areas, should be appropriate to improve the outer insulation creepage distance of porcelain.