(1) Power failure and fire extinguishing:
1. Power-off technical measures: In order to prevent electric shock accidents on the fire site, the cooperation of electrical technicians should be the first step in power-off, and the following technical measures should be taken when special power-off equipment is used to cut off the power supply:
A. The main switch of the substation is disconnected.
B. Cut off the power supply with jump fuse.
C. Request the power supply bureau to blackout the area where the transformer is located.
2. Fire extinguishing measures after power failure: When transformer fire occurs, the method of fire extinguishing after power cut off is the same as that of combustible liquid fire extinguishing.
A. If the fuel tank is not damaged, dry powder, 1211, CO2 and other fire extinguishers can be used for extinguishing.
B, if the fuel tank breaks down, a lot of oil will flow out and burn. When the fire is fierce, cut off the power supply and use spray water or foam to fight. The oil fire scattered can also be buried with sand. When the maximum time, the oil can be trenching and the oil will be put out with foam.
C. Large-scale substation equipment, there are many qualified insulating bushings, these bushings are easy to burst and damage the equipment in high temperature or uneven cooling, which may cause unnecessary losses. If the insulation oil is burst, the insulation oil will be dispersed and the fire will expand further. Therefore, it is better to use spray water to extinguish the fire and pay attention to the uniform cooling equipment.
(2) Live fire extinguishing:
In fire fighting, equipment is often charged. In some emergency situations, in order to fight for fighters, it is necessary to carry out fire fighting under charged conditions. Sometimes when the power supply can not be cut off due to production needs or other reasons, or when there is still a high residual voltage after the power supply is cut off, live fire extinguishing is also needed. The key to live fire extinguishing is to solve the electric shock hazard. When various safety measures are taken, the fire extinguishing method for live transformer is the same as that after power failure.
1. Fire extinguishing with live fire extinguisher:
(1) Commonly used fire extinguishers and minimum safety distance: Commonly used fire extinguishers are CO2, 1211, dry powder, etc. These fire extinguishers are not conductive and have sufficient insulation capacity. For the sake of safety, we should make the minimum safe distance between human body and charged body not less than 3m.
2. Notes: First, pay attention to the operation essentials and use requirements; second, try to spray in the upper wind.
(3) Keep the minimum safe distance.
2. Start fire extinguishing device live fire extinguishing:
Fixed or semi-fixed fire extinguishing devices play an important role in timely extinguishing initial fires, protecting equipment and preventing the spread of fires. At present, the fixed fire extinguishing devices used in power plants and power supply systems are water vapor, 1211 and foggy water, etc. However, as far as the current situation of our country is concerned, there are few fixed fire extinguishing devices in outdoor transformers.
(1) 1211 devices. In transformer substation, 1121 fire extinguishing device is commonly used. Its sprinkler is installed around the upper and lower oil storage of transformer, so that fire extinguishing agent can be focused on the combustion area.
2. Water spray fire extinguishing device: in reality, it only aims at indoor large and important substation equipment, computer room and power supply system. It adopts automatic control system, which can automatically alarm and extinguish fire in case of fire.
3. Fire extinguishing with live water:
Water can conduct electricity. It is harmful to human body to use water column of direct current water gun to extinguish fire of charged equipment. According to the experiment, the resistance of the human body is about 1000 ohms. When the current passes through the human body for 1mA, the human body feels electrified. Therefore, if the electric current through the human body is not 1mA, the safety of the fire extinguishers can be guaranteed.
(1) The factors affecting the leakage current of water gun:
A. Effect of water resistivity: Different media have different resistivity, and their conductivity varies with impurities. When water with high water resistivity is used for live fire extinguishing, the resistance of water column will be large and the leakage current through water column will be small, so the safety level can be improved. It is not conductive to use chemically purified water, but it is impossible in reality.
B. The influence of voltage on leakage current: When using direct current water gun to extinguish a fire, if the power supply voltage is relatively high, the leakage current through the water column is also relatively large. Therefore, attention should be paid to the distance between the nozzle of the water gun and the charged body.
C. The influence of distance between water gun nozzle and charged body on leakage current.
The longer the distance between the nozzle and the charged body of the water gun is, the longer the water column is, the greater the resistance of the water column is, and the smaller the leakage current through the water column is. Therefore, if the direct current water gun is used for live fire extinguishing in the fire field, it can give full play to the long range characteristics of the direct current water gun, properly increase the distance between the nozzle of the water gun and the charged body, so as to improve the safety of live fire extinguishing with water, and also can properly use the direct current water gun for direct fire extinguishing.
D. The influence of nozzle diameter on leakage current;
Under the condition of the same voltage, the same resistivity of water and the same distance, the leakage current through the water column of small caliber water gun is smaller than that of large caliber water gun. When using direct current water gun for live fire extinguishing in fire field, if the voltage is relatively high or the resistivity of water is relatively small, in order to improve the safety, small caliber water gun should be used. If the water consumption for fire extinguishing needs to be increased, the number of small caliber water guns can be increased without changing to large caliber water guns.
E. The influence of water pressure on leakage current.
Popularly speaking: when the pump pressure increases, the full water column emitted from the direct current water gun will increase correspondingly, the water column will be more compact, the current will pass easily, and the leakage current will increase with the increase of pressure. If the water flow is blooming, the greater the pressure of the pump, the better the dispersion of the water flow and water droplets, the more uniform the gap between the water droplets, and the resistance will increase correspondingly, and the leakage current will increase accordingly.