Harmonics pollute the electrical network and make equipment connected to it behave erratically.
Harmonics can cause damage to sensitive electronics, interference in communication equipment, and false readings on measurement devices. Harmonics can trip circuit breakers, blow fuses and cause capacitor failures. The effects also include overheating of transformers, cables, motors, generators and capacitors. Equipment must be designed to tolerate harmonics in the network, and oversizing leads to higher investment costs and underutilized capacity.
The problems caused by harmonics result in increased losses because more energy is wasted due to overheating, equipment has a shorter life time and is subject to unreliable operation. In the worst cases, harmonics cause unnecessary and unwanted process interruptions.