Reactive power consumption

Significant increase and development of production and city infrastructure is being observed in recent years. In this connection at the places of production the number and power of electrical receivers, involved in the basic technological and auxiliary cycles, is increasing. And consequently, the total power consumption is increasing.

Energy saving at the factories first of all depends on its efficient utilization when operating separate industrial systems and manufacturing plants. Such standard systems and plants of any manufacturing processes are: lighting systems, production equipment electric motors, electric-heating plants, welding equipment, converters, transformers etc.

The majority of above-mentioned electric plants used in the production processes, along with the active energy (P, kW), absorb as well reactive energy (Q, kvar), due to large inductances. This is inevitable for providing normal operation of such equipment, but it leads to network overload.

Unlike active energy, which is converted into useful – mechanical, thermal etc. - power, reactive energy is not connected with execution of any useful work, on the contrary – it is spent on generation of electromagnetic fields in electrical motors, transformers, induction furnaces, welding transformers, chokes, lighting appliances.

Parameter indicating reactive energy consumption is a power factor сosφ. It defines the ratio between active power Р and total power S, consumed by electrical receivers from the network:

The lower is the value of сosφ, the less effective is the power plant operation.

Reactive power always represents a factor reducing electric energy quality and leading to such negative consequences as increase of payment to utility company, additional losses in electric lines as a result of current increase, oversizing of transformers power and cable cross sections, high nominal deviation of mains voltage.