Regulated and unregulated capacitor units KRM
The difficult economic situation in the country prompts builders to think about the cost item. Costs must be reduced. The cost of construction is influenced by a variety of factors: the cost of operating the technical fleet, the price of building materials, employee wages, and much more. However, the most important thing becomes the elaboration of cost estimates at the preliminary preparation stage. That means it is necessary to work out in as much detail as possible the PPR – the work execution plan.
Let's consider the issues that the work execution plan includes:
– determination of the scope of work;
– compilation of their list;
– building the technological sequence and algorithm of work;
– determination of methods for performing the necessary work;
– calculation of required labor costs, number of shifts, and required man-hours;
– calculation of machine hours;
– creation of a general plan for the constructed facility;
– calculation of required power supply for the construction site;
– list of necessary materials and calculation of their cost.
For example, let's calculate the power supply for our construction site.
The algorithm for calculating power supply consists of the following points:
– determine the consumers of electrical energy;
– select the necessary sources of electricity;
– calculate the power of these sources;
– draw up a working power supply scheme for our construction site.
It is easy to see that the main consumer of electrical energy on the construction site is the company's machinery park. That is, all these cranes, mechanisms, construction installations – in general, all construction equipment.
Having identified the electrical load of current consumers (welding equipment, all electric motors, lighting systems, etc.), one can determine the required power of temporary power supply sources. After all mechanisms and machines that consume electrical energy are identified, and taking into account the power of current consumers, a general calculation of the total electrical load is performed. It is necessary to take into account both the active load, which is converted into thermal, mechanical and other types of energy, and the reactive load – it goes to create electromagnetic fields in mechanisms, transformers, electric motors, etc.
For any current consumer, the calculated power factor cos φ will be from 0.5 to 1.0. Taking into account inevitable losses in the transformer, the average power factor, which is 0.92 for the construction site, will decrease to 0.9. Hence, the total calculated reactive load will equal 107.33 kVA.
We will also include in the calculation a compensator, a capacitor unit for reactive power compensation UKM or KRM, which compensates for losses on the reactive load, initially calculated at 75 kVA. Thus, the total reactive load is reduced by more than half – by 70%! At the same time, cos φ increases to 0.99. As a result, the total load on the facility can be reduced by as much as 9%.
Consequently, through the use of a reactive power compensator, the costs for power supply of the construction site are reduced quite significantly: savings range from 10 to 15%.
A competent approach to cost accounting will significantly reduce the cost of construction. This is very important not only on a local but also on a global economic scale: a decrease in construction costs will help attract financial investments into the housing construction sector. Overall, this will not only help stabilize the construction industry but also contribute to its development, despite the current situation in the global and domestic economy.
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