What is the Definition of Zero Sequence Currents?

Harmonics and Sequence Currents

• Electrical voltages and currents produce harmonic interference at integer multiples of the fundamental power frequency.

Identification

• Zero sequence currents are harmonic feedback loops found in four-wire systems. The third phase in the series produces voltages that feed back into the neutral bus.

Source

• The source of zero sequence currents are single-phase, non-linear power loads in computers, photocopiers and mainframes. According to the IR Info website, zero sequence currents consume more than 80 percent of the total current in these devices.

Damage

• These currents can damage low-level electronic devices and any power systems connected to them. The IR Info website suggests a high neutral current and low power level may indicate the presence of zero sequence currents.

Harmonics Analyzer

• Zero sequence currents provide a power quality dilemma and require the use of harmonic analyzers. Hammond Power Solutions suggests measurements made by harmonic analyzers can pinpoint distortions by their voltage and current signatures.

Harmonic Filter

• A zero sequence harmonic filter, or ZSF, connects to a power distribution system and attracts zero sequence currents back to a neutral flow conductor.