Eight major harmonic hazards promote the application rate of green and low-carbon UPS
China Education Equipment Purchasing Network News: According to the information released by Computer Room 360, the harm caused by harmonic currents is very large. From the perspective of the performance of the power grid, harmonics have eight major hazards. This leads users to consider using green UPS to prevent harmonics Of pollution.
With the development of science and technology, energy and environmental issues are becoming more and more prominent, which requires the UPS industry to develop toward "green, low-carbon". However, the true green "low-carbon" UPS power supply is manifested by the small harmonic current on the power grid. The harmonic pollution is small, the efficiency of UPS operation is high, and the loss is reduced.
Low-carbon development (or low-carbon economy) is gradually becoming a global trend and is widely regarded as the only path for human development in the world. After the "Copenhagen Conference", the Chinese government successively issued a series of "low-carbon" environmental protection policy measures. In 2010, it was nicknamed "China's first year of low-carbon". With changes in policies and consumption environment, "green UPS" and "green UPS technology" have become the strategic highlands for the leading UPS markets. Lead-free production, DSP technology, IGBT rectification technology, APFC technology, etc. have all made great progress. And use.
The ideal UPS should be purely resistive to the power grid, that is to say, the power factor of the UPS is preferably 1, so that it does not have any pollution to the power grid. But the reality is that most UPS generally use 50Hz The low-frequency thyristor rectifier produces a large amount of harmonic feedback pollution to the city power. The problem before all users is to control the harmonic pollution, just like we treat the sewage discharged by chemical plants. Harmonics cause great harm.
The harm of harmonics mainly lies in:
1. Make the motor generate additional loss and heat, generate pulsating torque and noise. Transform power, cause additional losses and heat generation in the motor, and generate pulsating torque and noise. Make the power transformer coil heat, accelerate the aging of insulation, shorten the life, cause additional loss and noise.
2. Disturb the circuit breaker, leakage protector, relay and other protection and automatic control devices, causing malfunctions.
3. Shorten the life of lighting facilities.
4. It causes measurement errors of ammeter, voltmeter, power meter and electric energy meter.
5. Generate electrostatic interference and electromagnetic interference to the adjacent communication lines.
6. The series / parallel resonance of the electrostatic compensation capacitor of the power distribution system is caused.
7. Increase the loss of distribution lines, generate heat, shorten the insulation life, and even cause short circuit and fire.
8. Due to harmonics, the voltage mutation causes damage to electronic equipment and malfunctions, which affects the normal operation of computer programs. It causes data loss and even damages the hardware, causing the building automation, fire alarm system, and security protection system to malfunction or even fail to work.
At present, the main ways of dealing with UPS harmonic pollution in the market are: 6-pulse rectifier + input filter; 12-pulse rectifier; 12-pulse rectifier + input filter; active filter. These methods have a common disadvantage, that It is pollution before treatment. Because the UPS uses a thyristor rectifier structure, it will inevitably cause harmonic pollution, and then the user is forced to spend a lot of money to control harmonic pollution. If the UPS does not produce or rarely produces Harmonic pollution, then users do not need to spend money to control it.
If you want to achieve the same index, you need to add many options such as input filter, 12-pulse rectifier, etc., each additional option will further reduce the overall efficiency of the UPS. Therefore, the 12-pulse rectifier will reduce the efficiency by 2%, and the active filter will reduce the system efficiency by 4%. Therefore, in the actual measurement, the overall efficiency of many 12-pulse UPS is still less than 88%. Many people only pay attention to UPS price comparison when purchasing UPS, but they do not know how to measure the operating cost of UPS.
For example, an HP9330C series 80KVA (64KW) UPS has an overall efficiency of 95%, while a 12-pulse rectifier has an efficiency of only about 88%. In the 10-year UPS life cycle, the HP9330C series UPS The electricity cost saved is 64 (KW) × (95% -88%) × 24 (hours) × 365 (days) × 10 (years) × 1 (yuan / degree) = 392,448 yuan. The power consumption will be based on heat The form emanates, so that users also have to pay a large amount of electricity for air conditioning and cooling, and UPS has saved nearly 400,000 yuan in electricity charges for users.
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