One consequence of reactive power is overheating of electrical installations. Overheating can occur in various parts of the installation, including cables, distributors and transformers. This negatively impacts operational lifetime of these components and entails extra costs for service, maintenance and investment. In addition, overheating presents a safety risk.
Overheating of installation components
Every cable, transformer, distributor and other electrical device has its own specific electrical resistance. additional reactive power flows through these installation components, heat will increase in the resistors. Elevated temperatures, in turn, provide an additional increase in resistance with a possible escalation as a result.
Cable connections are the weakest link
Cable connections, the weakest parts of an installation, are often the first to suffer the consequences of reactive overheating. Insulation around these links will burn and, after some time, the possibility arises of the installation catching fire.
This is due to the fact that the apparent power (kVA) transported through the cable is much higher than the actual power (kW). The cause of this is the abundance of reactive power (kVAr) which increases the apparent power (sum of the actual power and reactive power). In some cases, the apparent power, which may be signficantly higher than the actual power, is not taken into account.
Reactive power: an unnecessary cost factor and security risk
Overheating caused by reactive power not only poses a safety risk, but also has an adverse effect on the operational lifetime of all installation components through which reactive power is transported. These installation components are more likely to cause problems in the event of prolonged overheating, which entails additional service costs. What’s more, cables, distributors, transformers and, in some cases, other installation parts need to be replaced earlier than expected, which means unexpected investment costs.
In addition to overheating, reactive power may have other consequences, including tripping of fuses and protections, loss of capacity in the installation and in some cases even fines from the energy supplier.