Every person whose work is related toelectrical engineering, should be well aware of what the term "installed power" means. During installation, this allows the most efficient way to choose the power source, as well as properly perform the necessary matching calculations.
In the definition given by the Soviet dictionaryThe power engineering specialists of 1984, the installed capacity of any electrical installation is understood as the largest active component of all its capacities, allowing the entire installation to operate for a long time in normal mode without overload, according to the passport data. However, in this case it is hardly possible to speak about a clear definition. In fact, everything is quite simple.
Imagine a situation familiar to many whenthere is a need to replace home wiring. It would seem that there are no difficulties. But it is not. One of the key points is the selection of the conductor section. It is performed on the permissible current or, which is also true (albeit with some reservations), on the value of power. For example, one incandescent lamp, an electric kettle and a microwave oven are placed in the room. Installed power is the sum of all active components of each appliance, that is, 100 W + 1200 kW + 2000 kW = 3300 kW. Any reactive load, if any, must be accounted for separately (total power in kilovolt-amperes). Electric motors and fluorescent lamps are the most common such consumers. So, the first point is that the installed power is not actually consumed, since it is not at all necessary that all electrical appliances should be switched on at the same time.
In the case of the power supply system,the sum of all its components of generating capacity (current sources). An example is the network of substations in production. It is important to note the utilization of power. It represents the ratio of electric energy produced during the reference period of time to its design value. For example, for a month, generators produced 10 MW of energy per consumer, while the theoretical limit of output is 100 MW. Obviously, the generating capacity is used inefficiently and idle. Indirectly, this means "extra" costs for the purchase and maintenance of electrical equipment. At the same time, this factor is also required in the calculations to account for the time required: scheduled maintenance (with shutdown), fuel loading (for NPP and CHP), etc.
In the above example with wiringThe demand factor for electrical equipment is used. In fact, this is a correction value, which allows to take into account in the calculations the fact that almost never all electrical consumers are activated at the same time. For a single device, its power must be multiplied by a factor, which will give the actual value. The coefficient is selected according to the tables depending on the characteristics of consumers. The use of such a solution allows significantly (sometimes more than twice) to reduce the cost of equipment and related materials, simplify subsequent maintenance.
For example, in the case of the calculation of lighting networks, this coefficient is assumed to be:
- 1.0 for emergency lines (which is quite understandable - power consumption is relatively low, and work is short-term).
- 0.6 - storage rooms. As a rule, the inclusion of light is needed only when using buildings.
- 0.8 - domestic facilities in the production. Specific changes are made by specificity (sometimes the light is on around the clock), but on average, the calculation from 0.8 is correct.
- 0.95 - buildings with large spans. Sometimes even on a sunny day there is a need for lighting, etc.
