Electricity: Active and Reactive Power
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 necessary for the creation of an electromagnetic field.
The reactive component of power loads the electrical lines, leading to the need to increase the cross-section of power cables and wires, which affects the costs of enterprises for organizing normal electricity supply.
Consumers of Reactive Energy
The main consumers of reactive energy are:
- asynchronous type motors;
- induction furnaces;
- power and welding transformers;
- electrical transmission lines;
- other electrical installations that operate on the principle of creating an electromagnetic field.
Expert estimates show that about 60% of all reactive electric energy consumed worldwide is used for the operation of asynchronous electric motors, and approximately 25% is used for transformers.
Compensation of Reactive Power
To reduce the value and compensate for reactive power in operating electrical installations, it is necessary to:
- optimize the technological process to reduce the energy intensity of reactive load consumers;
- reduce the idle time of welding transformers, asynchronous electric motors, and other equipment through organizational and technical measures;
- remove underloaded electrical equipment from operation if it does not affect the reliability of electricity supply;
- install frequency converters on asynchronous electric machines under the conditions of their operational technological cycle;
- replace outdated asynchronous equipment with new synchronous type equipment;
- improve the quality of repairs for electric machines to increase their efficiency.
The above measures can reduce reactive power consumption by more than 10% overall. The main role in this process is assigned to compensating devices, which include: synchronous electric motors, capacitor installations, compensation converters, and cosine capacitors.
Advantages of Capacitor Installations
The wide use of capacitor installations in reactive power compensation systems is explained by:
- low specific losses of active power;
- absence of moving parts;
- convenience and simplicity of installation;
- competitive cost;
- the ability to compensate over a wide range;
- silent operation;
- the possibility of automatic operation.
Unlike synchronous compensators, which can be both producers and consumers, capacitor batteries only perform the function of compensating for reactive energy.
Synchronous Electric Machines
Synchronous electric machines are popular for compensating reactive power. Synchronous motors increase the power factor j, which reduces the cost of electricity for consumers, and act as generators of reactive energy even when operating in idle mode.
The main differences between a synchronous motor and a reactive power compensator lie in the lighter rotor and shaft, as well as in the reduced air gap.
Given the trends towards increasing the cost of reactive electric energy, most enterprises are implementing compensation systems for this indicator in their energy systems.