Third harmonic (H3) : tertiary sector

In the tertiary or public sector (offices, hospitals, public buildings,...) the current is provided using an UPS. This UPS  supplies monophasic, not linear users. These kind of users (electrical-medical equipment, electronical ballasts, airco's, office equipment,...) generate harmonic currents and more specific the third harmonic (H3).

This third harmonic current is added to the current in the neutral. The current in the neutral is higher than the current in the phases. This causes damage in the neutral and even fire (the section of the neutral is often the half of the section in the phases).

Third harmonic currents cause disturbance in electronical applications.

Disadvantages of harmonic currents are :

• A sudden cutting off of the differential switch
• overheating of the neutral
• flickering of the lighting and screens
• extra charging (up till 15%) of the transformer

Comar Benelux developed a filter to solve these problems. The third harmonic current is filtered out on the network, where this filter is installated.

Advantages of the filter :

• Reducing the third harmonic current in the phases
• Reducing the third harmonic in the neutral
• Reducing the temperature loads in transformers, cables, fuses, vending machines, ...
• Reducing the capacity losses of transformers, cables and other network devices
• Saving energy
• Reducing electro magnetic fields