The reason for the large harmonics in nonlinear load power supply

The reason for the large harmonics in nonlinear load power supply

Include the following:
The characteristics of nonlinear components: The resistance value of components (such as diodes, transistors, etc.) in nonlinear loads varies with voltage or current, resulting in non sinusoidal waveforms between current and voltage, thereby generating harmonics.
Non synchronization of voltage and current: When a sine wave voltage is applied to a nonlinear component, due to the nonlinear characteristics of the component, the current will not change synchronously with the voltage, resulting in a current that is not a sine wave and generates harmonics.
Load characteristics: The components in nonlinear loads are not linearly related to the applied voltage, resulting in distortion of the current waveform and generation of harmonics.
Common types of nonlinear loads: Common nonlinear loads include UPS, switching power supply, rectifier, frequency converter, inverter, etc.
The impact of harmonics on the power supply system:
High neutral current: In the three-phase four wire system of single-phase nonlinear loads, the third harmonic is neutralized, but the neutral current will exceed all phase currents, which may cause neutral overload and even fire.
Circuit breaker failure: Harmonic currents may cause the circuit breaker to malfunction, affecting the stability of the power supply system.
Overheating of busbars and terminals: Harmonics can cause overheating of busbars and terminals, increasing circuit losses and fault risks.
Cabinet vibration: The magnetic field generated by harmonic currents may cause mechanical resonance of switchgear, leading to cabinet vibration and buzzing sound.
Communication interference: Harmonics can affect communication systems, causing interference and malfunctions in communication equipment such as telephones.
Transformer failure: High frequency harmonic currents can increase transformer losses and heat generation, which may cause overheating and damage to the transformer.
Methods to solve harmonic problems:
Using filters: Installing filters in the power supply system can effectively reduce the generation and propagation of harmonics.
Adjust load configuration: Reasonably configure the load to avoid the concentrated use of a single type of nonlinear load.
Using passive filters or active filters: Passive filters can filter out harmonics of specific frequencies, while active filters can dynamically compensate based on real-time detected harmonics.
Regular inspection and maintenance: Regularly inspect the harmonic situation of the power supply system, promptly identify problems, and carry out maintenance.