How to carry out high voltage safety protection?
1. Personal safety protection
When repairing cars with high-voltage electricity, maintenance personnel must protect themselves from being injured by high-voltage electricity. Although existing electric cars are designed to prevent accidental electric shocks, high-voltage power always exists for accident cars and the high-voltage power battery pack assemblies of these cars.
Personal protective equipment to prevent electric shock mainly includes insulating gloves, goggles, insulating shoes, and non-chemical fiber clothing.
①Insulating gloves. As shown in Figure 1, insulating gloves for high-voltage car maintenance usually have two independent properties: electrical insulating gloves made of rubber are required to be used for any operation related to high-voltage components or lines, and can withstand 1000V The above working voltage: Second, it has alkali resistance, when it comes into contact with chemicals such as hydroxides from the high-voltage power battery pack during work, it can prevent these substances from harming human tissue.
Insulating gloves require periodic inspection and must be self-checked for leaks before each use. The method of inspection is to blow a certain amount of air into the gloves to observe whether there is a risk of air leakage in the gloves.
②Goggles. As shown in Figure 2, goggles prevent battery fluid from splashing into the eyes. The goggles used for the maintenance of high-voltage electric cars should have a side protection function to prevent the electric sparks generated during the maintenance process from damaging the eyes.
③ Insulating shoes. The function of insulating shoes (boots) is to insulate the human body from the ground, prevent the current from passing through the human body and the ground to form a path, cause electric shock damage to the human body, and minimize the danger of electric shock. Because the current during electric shock flows into the ground through the human body through the contact point, it is necessary to wear not only insulating gloves but also insulating shoes during electrical work.
As shown in Figure 3, the insulating shoes are produced according to the standard, and the resistance value ranges from 100k ohms to 1000MΩ.
Insulated shoes should also be inspected regularly.
④ Non-chemical fiber work clothes. When repairing the high-voltage system, non-chemical fiber work clothes must be worn. Chemical fiber work clothes will generate static electricity, and in the event of a fire accident, chemical fibers will adhere to human skin in a high temperature environment, resulting in serious secondary injuries to maintenance personnel.
2. Use insulated repair tools
When maintaining high-voltage cars, tools with insulating functions must be used. These tools include commonly used sockets, wrenches, screwdrivers, pliers, electrician’s knives, etc., as well as special instruments (such as digital multimeters), as shown in the figure 4 shown.
The use of insulated tools can effectively prevent accidental electric shock accidents. There are three types of insulated power tools.
① Class I tools: refers to electric tools with ordinary basic insulation. In terms of protection against electric shock, it not only relies on basic insulation, but also should add a safety precaution, that is, it is not charged under normal conditions, but when its basic insulation is damaged, the exposed conductive parts of the charged body are protected and connected to zero. In order to be reliable, there should be no less than two zero protection connections, and additional leakage protection should be added. At the same time, the operator is required to use insulating protective equipment.
②Class II tools: refers to electric tools with double insulation or reinforced insulation. In terms of protection against electric shock, they not only rely on their basic absolute image, but also have double insulation between the live parts under normal conditions and the accessible non-charged conductive parts. Or strengthening insulation and isolation measures, which is equivalent to designing and manufacturing the operator’s personal insulating protective equipment on the tool in a reliable and effective way.
③ Class III tools: refers to electric tools powered by extra-low safety voltage. Rely on the safety isolation transformer for power supply in terms of protection against electric shock.
In the maintenance of high-voltage electric cars, it is required to use Class II and above insulated power tools.