Modern inhabitant metropolis developed not imagine his life without all sorts of instruments and mechanisms.But most of them are operated by electricity consumption.So sometimes it seems that the present normal activity impossible without it.Currently, the network of electrical tightly entangle virtually all populated corners of the globe.Their design is the simplest representation of a plurality of sources and points of transformation, distribution and transmission of this species.However, some consumers need a constant and uninterrupted supply, while the individual devices can be in a certain time without being connected to the main power line.So what is the group to include one or another mechanism?That question will be considered below the material.
Category reliability of electricity supply
As mentioned earlier, different devices have different requirements for the power from the system power supply.In the currently used classification comprising three basic groups, each of which is called "power supply section".It should be noted that such division is applicable to the individual power consumers.However, in most cases it is necessary to talk about them together.They can be present as the devices belonging to the first category, and the mechanisms that are assigned to the third.In such situations, you should pay attention to the amount of any power consumers prevails over the others.In this connection it was decided to treat the previously described group preferably one of the categories on the supply reliability.Let us consider each of these in more detail.
main feature
After considering this classification should understand on what it is based.The most important criterion for the separation of the above groups was the need for uninterrupted power supply from the mains.For example, you can not compare in significance ordinary private house in the village and any health care facility, such as a hospital.You agree that even the most insignificant break in the power supply operating rooms lead to harm human health and life, located at that time in the hands of doctors.Conversely, residents of an apartment house can stay without loss without electricity.
Group 1
Among the consumers of the first category of reliability of power supply are those instruments and mechanisms, a break in the supply of which is able to cause a threat to human life and health, a threat to the normal existence of the state and its security including a fairly largematerial damage.In addition, it also includes violation of complex processes, a devastating change in the functioning of strategically important components of television and communication, as well as public utilities.The first category of supply, as mentioned earlier, includes responsible enough receivers of electric energy, so there is a certain number of requirements to them.
One such power supply can be considered from two unrelated sources.That independence is the most important criterion.The use of such schemes due to a significant decrease in the risk of accidental disconnection from the mains receivers.Considered category allows power interruptions in the flow of energy only for the time necessary and sufficient for automatic switching from one source to the other.
first special category of power
We should also select a group of devices that are characterized in that they require an absolutely uninterrupted power supply network.This category includes power receivers of energy that is continuously working to safely stop the production flow, prevent the occurrence of a fire or other emergency.An important condition for the effective operation of such electric machinery is to use a third independent source of supply.For example, it may be a diesel generator or batteries.In this case, if it becomes impossible to supply energy from two main points of supply, the work immediately enter the third.Nevertheless, the probability a situation where there is no possibility to use the aforementioned additional source.In this case, application of so-called technological reserve, which also contributes to the smooth and fast as possible halt of production activities.
Group 2
second category of electricity consumers has some indulgences of the claimant to the mains supply.It includes such receivers and devices outage that can cause a significant reduction in the release of manufactured products, production downtime vehicles and equipment involved in a particular process.In addition, this category of power, disabling a certain period of time may result in the disruption of normal living conditions of a significant number of residents of the state.Requirements for feed-similar to the criteria for the first group, but there are some differences.Second category of power supply needs to receive a power of two places, but allowed the temporary absence of power, enough to switch from one source to another through the visiting team networks or operating personnel of the consumer.
Group 3
This group is the most extensive.3 category of power supply includes all the devices that have not been put in the previously mentioned groups.Nevertheless, it imposes some requirements.For example, the term of a power interruption is allowed no more than 72 total hours in a year and not more than 24 consecutive hours.
Application in practice
It should be noted that the category of utility power can be changed when required.Of course, everything depends on its purpose.If we consider a production area, it is likely he will be assigned to the first or second group of reliability.In contrast, a category of power supply of residential houses will be the third most frequently.
Conclusion
normal vital functions of any modern man is not easy to imagine without electricity.Reliable supply of such resources was essential for the effective operation of factories and industrial enterprises, educational institutions and health care components of the housing sector and elements of agriculture.
