Reactive Power Compensation
What is Reactive Power?
Every device powered by electricity draws both active and reactive power from the electrical network. The former is converted into useful work—heat, motion, or light—while the latter is not converted into work but is necessary for the proper functioning of the device. Furthermore, unlike active power, reactive power does not flow in one direction between the power plant and the consumer but circulates between them.
Reactive power is divided into two types: inductive and capacitive. Inductive reactive power is drawn from the electrical network and is essential for generating a magnetic field in motors, transformers, or chokes. These devices require a magnetic field to maintain the conditions necessary for performing work. On the other hand, capacitive reactive power is returned to the electrical network by various devices, including LED lighting and capacitors.
Although the presence of reactive power is necessary, it generally increases active power losses and worsens the operation of circuit breakers. It can also contribute to more frequent network failures, as it causes voltage drops in supply lines and transformers.
Regulations limit the amount of reactive power drawn. The key factor here is the power factor tangent (tg ∅), which defines the ratio of inductive reactive power to active power. Exceeding a value of 0.4 incurs financial penalties imposed by distribution system operators. Electricity distributors also charge fees for introducing capacitive reactive power into the network and for excessive volumes of inductive reactive power.
For these reasons, it is beneficial to take measures to limit the transmission of reactive power over long distances. This is where the term reactive power compensation comes in, which refers to storing reactive power close to the point of demand.
What is Reactive Power Compensation?
Reactive power compensation involves installing devices that generate reactive power near the consumers, thus eliminating the need to transport it through the electrical network. To compensate for inductive reactive power, capacitor banks are typically used, while for compensating capacitive reactive power, inductive choke banks are employed. By using compensatory devices, the amount of reactive power drawn from the network is reduced, and the possibility of exceeding the permissible value of the power factor tangent is eliminated.
Benefits of Reactive Power Compensation
It is very likely that your electricity bill includes a line item related to reactive power, which is associated with additional charges. If you are a business owner, particularly in the industrial sector, you probably feel the expenses incurred from reactive power. The problem primarily affects machines with inductive motors, UPS systems for computers, LED lighting, and cooling equipment. Did you know that charges for excessive reactive power consumption can amount to around 20-30% of your electricity expenses? These costs can be mitigated, but first, you need to invest in reactive power compensation systems. Calculations show that this investment typically pays off within a year.
How to Select Reactive Power Compensation Devices?
Selecting reactive power compensation devices is undoubtedly a task for specialists. While you can research the topic, choosing capacitor banks for reactive power compensation on your own is often very challenging. It is advisable to entrust this task to a company that specializes in such matters. One such company is Innogy Polska, which offers individual consulting and assistance in improving energy efficiency for businesses.
Why is it complicated to select reactive power compensation devices on your own? The type of capacitor bank should be chosen based on the devices used and other equipment powered by the same network. This often requires measuring network parameters at the location where the device will be connected.
Although reactive power is essential for the proper functioning of many devices, it generates energy losses and high costs, especially for businesses. However, you do not need to bear these costs. Investing in specialized compensation devices is worthwhile as it will lead to lower electricity bills.
