Harmonic filter resistors

The Harmonic Filter resistors are used to eliminate the dangerous distortions (harmonics) generated inside the network due to connection of more and more number of electronic power converters.

The main problems caused by harmonics, that are sinusoidal currents with different frequencies and amplitudes compared with the rated 50/60 Hz network currents, are:

•  increment of losses on the line
• malfunctioning of the test equipments
• interferences with radio and phone systems
• resonances
• high currents at neutral point

These Harmonic Filter resistors , used together with reactors and capacitors, help to reduce and filter the harmonics. The main characteristics of TELEMA resistors are:

• low variation of resistance value at hot condition
•  low working overtemperature
• high reliability
• high insulations, internal and to ground
• specific insulation design to guarantee the integrity of the unit in the event of  overvoltages for atmospheric discharges or switching in the network
• supported impulse test up to 400 kV
• all conductive parts are connected to a well-known potential