1. SF6 gas insulated substation
SF6 gas insulated substation (GIS) consists of multiple SF6 gas insulated switchgear combined in an outdoor enclosure, which can reach IP54 protection level. With the advantage of SF6 gas insulation capability (the arc breaking capacity is 100 times that of air), the gas insulated substation can operate stably for more than 30 years. All live parts are placed in a fully sealed stainless steel tank filled with SF6 gas. This design can ensure that the GIS is more reliable during the service life and requires less maintenance.
The medium voltage gas insulated substation is generally composed of 11KV or 33KV gas insulated switchgear. These two types of gas insulated substations can meet the application requirements of most projects.
GIS gas insulated switchgear station usually adopts economical and compact layout design during construction, so the advantages of GIS substation are as follows:
Compared with the normal size switchgear substation, it only occupies one-tenth of the space. Therefore, GIS gas insulated substation is the best choice for projects with small space and compact design.
2. Since the SF6 gas is in the sealed tank, the gas insulated substation components will work in a stable state, and there will be much fewer failures than the air insulated substation.
3. Reliable performance and maintenance-free.
Disadvantages of GIS gas insulated substation:
1. Cost will be higher than ordinary substation
2. When a failure occurs, it takes much longer to find the cause of the failure and to repair the GIS substation.
3. Each module cabinet must be equipped with an SF6 gas pressure gauge to monitor the internal gas pressure. The gas pressure reduction of any module will lead to the failure of the entire gas insulated substation.
2. The harm of sulfur hexafluoride leakage
Pure sulfur hexafluoride (SF6) is a non-toxic and odorless gas. The specific gravity of sulfur hexafluoride gas is higher than that of air. After leakage, it sinks to a lower level and is not easy to volatilize. After being inhaled by the human body, it will accumulate in the lungs for a long time. Inability to excrete, resulting in reduced lung capacity, severe dyspnea, suffocation and other adverse consequences. In view of the harm caused by the leakage of Sf6 sulfur hexafluoride gas to the human body, experts give the following:
1. Sulfur hexafluoride is a suffocating agent. In high concentrations, it can cause breathing difficulties, wheezing, blue skin and mucous membranes, and body spasms. After inhaling a mixture of 80% sulfur hexafluoride + 20% oxygen for a few minutes, the human body will experience numbness of the limbs and even death by asphyxiation.
2. The decomposition products of sulfur hexafluoride gas under the action of electric arc, such as sulfur tetrafluoride, sulfur fluoride, sulfur difluoride, thionyl fluoride, sulfuryl difluoride, thionyl tetrafluoride and hydrofluoric acid, etc. , They are both strongly corrosive and toxic.
1. Sulfur tetrafluoride: It is a colorless gas at room temperature with a pungent odor. It can generate smoke with moisture in the air, which is harmful to the lungs and affects the respiratory system. Its toxicity is equivalent to that of phosgene.
2. Sulfur fluoride: It is a colorless gas at room temperature, toxic, has a pungent odor, and has a damaging effect similar to phosgene to the respiratory system.
3. Sulfur difluoride: The chemical properties are extremely unstable, and the performance is more active after heating, and it is easily hydrolyzed into sulfur, sulfur dioxide and hydrofluoric acid.
4. Thionyl fluoride: It is a colorless gas, smells of rotten eggs, has stable chemical properties, and is a highly toxic gas that can cause severe pulmonary edema and suffocate animals to death.
5. Sulfuryl difluoride: It is a colorless and odorless gas with extremely stable chemical properties. It is a toxic gas that can cause spasms. Its danger is that it has no pungent smell and will not cause irritation to the nasal mucosa, so it will often die quickly after being poisoned.
6. Tetrafluorothionyl: It is a colorless gas with a pungent odor, which is harmful to the lungs.
7. Hydrofluoric acid: It is the most corrosive substance in acid. It has a strong stimulating effect on the skin and mucous membranes, and can cause pulmonary edema and pneumonia.
Sf6 sulfur hexafluoride gas leakage emergency treatment: quickly evacuate personnel from the leaked contaminated area to the upper wind, and isolate them, strictly restrict access. It is recommended that emergency response personnel wear self-contained positive pressure breathing apparatus and general work clothes. Cut off the source of leakage as much as possible. Reasonable ventilation to accelerate diffusion. If possible, use it immediately. Leaking containers should be properly handled and used after repair and inspection.
The sulfur hexafluoride gas detection function of the SF6 gas insulated substation is detected by the SF6 sensor. When a leak occurs or the ratio exceeds the standard, the first time it detects and sends out an on-site alarm or remote SMS or telephone alarm to remind the staff to leave the dangerous area and effectively prevent Serious harm caused by gas leakage.
Post time: Aug-20-2021
