What are the hazards of the harmonics generated by the UPS power supply?
For our long-term use of the UPS power supply, in the end UPS power supply which will produce what harmonics, the current harmonics in the end what will be the harm, the specific hazards are the following:
1, on the circuit breaker, leakage protection, relays and other protection, automatic control device interference, resulting in malfunction. So that the motor generates additional losses and heat, resulting in pulsating torque and noise. So that the power transformer, so that the motor generated additional loss and heat, resulting in pulsating torque and noise.
2, the adjacent communication lines produce static interference and electromagnetic interference. Causing the electrostatic compensation capacitor of the distribution system to occur in series / parallel resonance.
3, due to harmonics, so that voltage changes caused by electronic equipment damage, a malfunction, affecting the normal operation of computer programs. Resulting in data loss, and even damage to the hardware, causing building automation, fire alarm system, security system malfunction, or even unable to work.
Suppression of harmonic methods
Method 1, the use of 6-pulse UPS + active harmonic filter, input current harmonic <5% (rated load), the input power factor of 0.95. This configuration, although the input index is very good, but the technology is still immature, there are false compensation, over compensation and other issues, leading to the main input switch error trip or damage and other phenomena; THM active harmonic filter technology defects
Method 2, the use of 6-pulse UPS + 5 harmonic filter, if the UPS rectifier device for the three-phase full-controlled bridge 6-pulse rectifier, rectifier generated by the harmonics of all harmonics nearly 25-33% plus 5 harmonic Wave filter to reduce to 10% or less, the input power factor of 0.9, can be partially reduced harmonic current on the power grid hazards. This configuration, the input current harmonics are still too large, the generator capacity requirements for the ratio of 1: 2 or more, and there lead to abnormal increase in the output of the hidden dangers;
Method 3, the use of phase-shifting transformer +6 pulse rectifier false 12 pulse program, its composition consists of two 6-pulse rectifier ups into:
Method 4, the use of 12-pulse UPS + 11 harmonic filter, if the UPS rectifier device for the three-phase full control bridge 12 pulse rectifier, plus 11 harmonic filter reduced to 4.5% or less, can basically completely eliminate the harmonic Current content on the power grid hazards, the price is much cheaper than the active filter.
