What Should I Know About Electrical Safety?

In electrical engineering operations, the reversal of an operation sequence or the omission of one of the operation items may lead to serious accidents such as personal injury, equipment damage, and large-scale power outages, causing serious adverse consequences and even serious social impacts. .

Electrical operation is a high-risk, accident-prone industry. Therefore, safety measures must be taken for construction. Statistics show that the vast majority of accidents in electric power construction are not caused by the low skill level of the constructors, but because they do not have sufficient safety awareness.

Obviously, it is particularly important to conduct necessary safety education for electrical operators. Enterprises must always adhere to the "safety first, prevention first, comprehensive management" approach, and strive to formulate and improve their accident prevention mechanisms and long-term management mechanisms. People-oriented, the supervisory department should do its job well, strengthen the supervision of construction personnel, strengthen administrative law enforcement, eliminate all hidden dangers and ensure production safety. ^[2]

Electrical safety is the science and technology and management engineering related to electricity in the field of safety. Including electrical safety practice, electrical safety education and electrical safety research. Electrical safety is based on safety and applied science in the field of electricity. It includes electricity safety and electrical safety. Its basic theory is electromagnetic theory and safety principles.

Due to the widespread application of electrical energy, electrical safety is also extensive. No matter in the production or life fields, electricity cannot be separated, and various electrical safety problems will be encountered. Electrical safety also has comprehensive characteristics. It is not only closely related to the power industry, but also to various industries such as construction, coal, metallurgy, petroleum, chemical industry, machinery, etc. Furthermore, electrical safety work has both engineering and technical aspects. There is also an organizational management side.

Electrical safety evaluation includes two aspects of effectiveness and economic evaluation. This thesis focuses on the effectiveness evaluation of electrical safety. The evaluation of the system's electrical safety effectiveness is to evaluate whether the various parts of the system are reasonable in terms of electrical safety, whether the electrical safety precautions taken by each part are reasonable, whether they can coordinate work, and whether there is a dead zone of electrical safety in the entire system. . That is, to identify the electrical danger factors in the actual system of industrial enterprises, and to anticipate the possibility of accidents and the consequences of accidents due to electrical thermal effects, chemical effects, mechanical effects, etc., and then propose electrical safety measures and rectification suggestions.

For general industrial enterprises, electrical accidents mainly include electric shock, electrical fires and explosions, lightning hazards, and electrostatic hazards. However, for enterprises in different industries, due to the different raw materials, production equipment, production processes, etc., the focus of electrical accidents is different. For example, when an oilfield unit conducts electrical safety assessment, fires and explosions are major accidents with significant losses, so electrical fires and explosions, lightning hazards, and electrostatic hazards should be the focus of evaluation. For mechanical processing plants, because of the large coefficient of metal in the workshop, electric shock accidents are prone to occur, so electric shock should be the focus of evaluation. ^[3]

The safety principle states that, under certain circumstances, whether an accident occurs and the possible consequences are extremely contingent, but all have their profound causes, including direct and indirect causes.

Accidents are the consequence of social factors, management factors, and dangerous factors in production triggered by accidents. This is the basic point of view of the comprehensive theory of accident models. Based on this view, these physical, management, environmental, and human causes constitute risk factors in safety evaluation.

Although there are various types of electric shock accidents, the most common is accidental contact with a conductor that is not charged under normal circumstances and accidentally charged. As long as you can master its laws and take corresponding security measures, many can be avoided. The main technical measures to prevent electric shock accidents include the use of safe voltage to ensure the insulation performance of electrical equipment, the use of screens to ensure a safe distance, the reasonable selection of electrical devices, the installation of leakage protection devices, protective grounding, and zero connection.

1) In the work of the main power line through the wall pipe, the first consideration is the magnitude of the rated current of the load provided by the power line and the impact of the short-circuit current under special circumstances. The thermal effect of the line should be considered first. The reason is that when the wires penetrate into the tube, the space is limited, narrow and small, resulting in a small heat dissipation area. Over time, it promotes dangerous accidents due to aging of the insulation.

Secondly, when the wire is pulled through the wall during construction, it is very likely to cause unsafe factors. It can be seen that although the wire through the wall is a simple and common work method, it is often a common misoperation. As a result, the service life of the entire power supply line has been reduced, and thus human, material and financial resources have been wasted.

2) In the mechanical and electrical engineering of the ground, the selection is also very critical. The total power and reactive power of all electrical equipment should be calculated first, and then the matching transformer should be selected according to the calculated power value. During this period, some electromechanical personnel chose extra-large capacity and thought that only large capacity would be safe. In fact, the selection of large capacity wastes financial resources first, and wastes material resources. The most important thing is the increase of unsafe factors. For example, power transformers with a rated capacity of 100kv A / 380v, the protection setting range is 10A-200A, The 800kv A power transformer protection setting range is 100A-400A. It can be seen that if the current at 50A is on fire, if the power transformer protection setting with a small capacity is exactly 50A, it can immediately cut off the power and the capacity is large. However, it is not aware of the protection, because it is at least 100A, which shows that it is necessary to choose a suitable one, because it is economical, reasonable, and safe. So choosing the right power transformer is important. After the selection, the wiring is started. In the three-phase four-wire power supply, the current balance of the three-phase hot wire should be paid attention to, and then the three-phase hot wire should be separated from the neutral (ground) wiring. The main switch of the household (the main switch with leakage current), and then to the sub-switches, special attention is that on the switch, there are signs of live line and neutral line, must not be reversed, otherwise, the protection is lost The consequences are serious and unimaginable. Secondly, due to the intention of the constructor, in the electrical installation process, the standard is to enter the switch with the live wire, and the lamp into the lamp cap, and due to the negligence of the constructor, the fire wire into the lamp cap, and the zero wire into the switch, so that, Although the lamps are not lit, they still carry a single-phase 380v dangerous voltage which directly endangers personal safety. In this case, people generally think that when the lights are off, there is no electricity. Moreover, due to the paralysis of the construction workers, it is very easy to cause physical insecurity to the construction workers.

3) In the output power line of each substation, it is delivered to the electricity consumers through iron pipes preset in the wall. The design of the through-wall pipeline should first pay attention to that both ends of the iron pipe should be It is safe to be chamfered and then polished with gauze. Otherwise, the spikes at the ends of the iron pipe passing through the wall can scratch the insulation of the outside of the transmission line of the project. The wire is cut through directly, which directly affects the power supply, especially if the part inside the wall pipe is broken, the consequences will be very serious. First of all, it is difficult to check the fault, and secondly, it is difficult to handle the fault.

4) In the construction process of installing a lightning protection system, it is necessary to first clarify the importance and practical safety of the installation of the lightning protection system here, and then the skill and construction attitude and method of the welder builder, is it serious or confused? It will directly affect the safety of the power system. Due to poor welding during construction, false welding and false welding will be caused, which will cause the entire lightning protection system to fail to function properly. The safety consequences and economic losses will be disastrous. ^[4]

In short, electricity is one of the most important energy sources for human beings. With the rapid development of China's economic construction and the continuous improvement of people's living standards, various electrical equipment is gradually increasing, and the demand for electricity is also increasing. However, due to the rapid expansion of the construction of the power grid, more and more electrical wiring is being laid in construction and decoration projects. At the same time, the number of fires and losses caused by electrical lines has gradually increased.

Therefore, the prevention of electrical safety not only has important practical significance for ensuring normal production and living order, but also has become one of the important measures to maintain social public safety. ^[3]