Reactive power compensation

Electricity is supplied to consumers in the form of active and reactive power. Active electrical power is used to perform useful work, while reactive power is used to create an electromagnetic field

In addition, the reactive component of power loads electric lines, which necessitates an increase in the cross section of power cables and wires, and this affects the costs of the enterprise for organizing normal power supply

The main consumers of reactive energy are the following electrical installations:

• motors of asynchronous type;
• induction furnaces;
• power and welding transformers;
• power lines;
• other electrical installations with the principle of operation based on the creation of an electromagnetic field

According to experts, approximately 60% of all reactive electrical energy consumed in the world is spent on the operation of asynchronous electric motors, and about 25% is consumed by transformers

 

To reduce the value and reactive power compensation at existing electrical installations, it is necessary to carry out:

• optimization of the technological process with a decrease in the energy intensity of reactive load consumers;
• reducing the idle mode of welding transformers, asynchronous electric motors and other electrical equipment through organizational and technical measures;
• out of operation of underloaded electrical equipment, if this does not affect the reliability of power supply;
• installation of frequency converters on asynchronous electrical machines, if it is permissible according to the conditions of the technological cycle of their work;
• replacing obsolete asynchronous hardware with a new synchronous type;
• improving the quality of repair of electrical machines, thereby increasing their efficiency

These measures make it possible to reduce reactive power consumption by more than 10% in total. In this regard, the main role in the process of reducing consumption is assigned to compensating devices. These include: synchronous electric motors, capacitor units, compensation converters Today, synchronous electric machines are mainly used and cosine capacitors

 

The widespread use of capacitor units in reactive power compensation systems is due to:

• low specific active power losses;
• the absence of rubbing and rotating parts;
• convenience and ease of installation;
• low cost;
• the possibility of reactive power compensation in a wide range of values;
• silent operation;
• the ability to work in automatic modeUnlike synchronous compensators, which can be both producers and consumers, capacitor banks are designed exclusively to compensate for this type of energy

  Synchronous electrical machines are a fairly popular way to compensate for reactive power. Synchronous motors increase the cos j factor and thereby reduce the cost of electricity for consumers. Such a motor is a generator of reactive energy, even when it is idling

  The main differences between a synchronous motor and a reactive power compensator are a lightweight rotor and shaft, as well as a reduced air gap between them. However, the main disadvantage of synchronous compensators is the need for a power source, which is why the specific active power loss when using this method is much higher than for cosine capacitor units

  In connection with the current trend towards an increase in the cost of reactive electricity, most enterprises are implementing compensation systems for this indicator at their energy facilities. This allows not only saving financial resources, but also transmitting more active electric energy over the same lines

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