Avoidance of use of materials known to impact environment. Due to global warming, depletion of the ozone layer and degradation of the environment are on the rise. This topic explains how to reduce the carbo n footprint in our substation design. Manufacturing industry is consciously avoiding or removing materials that can impact the environment adversely. Few examples of environment, unfriendly materials are lead, mercury, cadmium, asbestos, PVC, PCB or polychlorinated biphenyls, oil and SF6 gas. Electrical equipment industries and consumers have consciously reduced the usage of lead and mercury. Usage of mercury vapor lamps, which was quite popular from the 1970s to 1980s, is on the vane. PVC is extensively used as an insulation material for cable. PVC supports better serviceability due to its longer life. There is no suitable alternative material to replace PVC. PCB oil, which was used in transformers and capacitors in the 1960s, is banned. At present, mineral oil is used. Transformer oil shall not drain into soil, as soil will be contaminated. Batteries contain materials like lead and cadmium, which are harmful to the environment. After the useful life, batteries shall not be disposed off indiscriminately. After the useful life of batteries, they have to be disposed off properly since they contain material which is harmful to the environment. Battery manufacturers undertake to take back the old batteries for resecting and safe disposal. The alternative to lead acid and nickel cadmium batteries are emerging like lithium ion. However, the lead acid and nickel cadmium batteries continue to be used in industry due to longer service life. As a result of this, the lead acid and nickel cadmium batteries are still in use, as in when economically viable alternative batteries emerge. These batteries may also be phased out. We use SF6 gas as an insulating or interrupting medium in MV, HV and EHV switch gear. SF6 gas is housed in virtually leak-proof compartments, and hence, exposure of SF6 gas to the environment is minimal. However, handling of SF6 gas shall be undertaken very carefully to avoid any leakage to the environment. We do not have mature technology to replace SF6 gas. Hence, the use of SF6 gas is being continued in electrical industries. However, recently, General Electric Corporation and Siemens reported that they have commenced use of an SF6 substitute in a smaller scale. We must also address noise pollution and light pollution in all design processes as they are harmful to humans and animals, excessive outdoor lighting shall be avoided. There are standards that specify maximum noise levels that the equipment can generate. Such requirements are more stringent in residential, hospital and school zones. Here is a quick recap of what you have learned thus far. Lead, mercury, cadmium, asbestos, PVC, PCB or polychlorinated biphenyls, oil and SF6 gas are some of the environmental pollutants related to electrical substations. As there are no alternatives, PVC continues to be used as an insulation material for cables. PCB oil that was widely used in transformers and capacitors in the 1960s has been replaced by mineral oil. Lithium ion batteries are fast emerging as an alternative to lead acid and nickel cadmium batteries. However, the later is still a preferred choice due to the longer service life and lack of economically viable alternatives. SF6 gas, even though harmful to environment, is still used as an insulating and interrupting medium in MV, HV and higher voltage switch gear. The development of a matured technology to produce a replacement gas for SF6 on an industrial scale is presently under progress. Measures to control light pollution and noise pollution due to substation equipment are important in the design process.
