Current Solution for Harmonic Suppression and Reactive Power Compensation in Public Buildings

At present, in order to save energy and enjoy convenient and comfortable living, UPS power supplies, electronic speed-control equipment, energy-saving lighting fixtures, and computers, microwave ovens, and other electrical equipment with power electronic devices used in homes are increasingly used in public buildings. This has led to a growing number of non-linear loads injecting harmonics into the power grid, causing the impact of power quality pollution to become increasingly significant. In areas where these devices are concentrated, such as large shopping malls, residential communities, office buildings, and hotel apartments, harmonic pollution has become quite serious. The effects of harmonic pollution not only cause a marked deterioration in power quality, but also cause line overheating and fire accidents, interfere with communication, burn fuses, and cause protective equipment to malfunction, among other potential hazards. Therefore, the suppression and treatment of harmonic pollution in power quality has become urgent. Our company's DF6501 series of active harmonic filtering and reactive power compensation devices can effectively solve the harmonic problem in public buildings, not only improving power factor and ensuring the safe operation of equipment in public buildings, but also preventing harmonics from flowing back into the grid and harming other users.

Solution Architecture: Typical harmonic sources in public buildings:
1. Lighting equipment in public buildings typically uses energy-saving lamps in large quantities, which can cause serious harmonic currents, with the 3rd harmonic being the highest. When multiple fluorescent lamps are connected in a three-phase four-wire load, the harmonic current on the neutral line will be the algebraic sum of the harmonic currents on each phase, causing the neutral line current to be too large and heating up seriously. In severe cases, it may cause the power line to collapse.
2. Air conditioning and ventilation equipment: In order to save energy, public places usually use variable-speed fans and air conditioners. Inverters are very serious harmonic sources, with their total harmonic current distortion rate exceeding 30%, producing large amounts of 5th and 7th harmonics that pollute the power grid. 
3. Computers and UPS: The establishment of computer network management in education, banks, and financial fields is inevitable, and the number of computers is very large. In addition, server-type data storage systems must be equipped with UPS and other standby power supplies. The power supply of personal computers and UPS are harmonic sources and will produce large amounts of 3rd, 5th, and 7th harmonics. 
4. Elevators: Elevators are now very common in modern buildings, and elevators are equipped with variable-speed drives to save energy. Inverters are very serious harmonic sources, with their total harmonic current distortion rate exceeding 30%, producing large amounts of 5th and 7th harmonics that pollute the power grid. The above equipment is a typical harmonic source that is widely used. 
For such a harmonic load-concentrated line, centralized treatment can achieve a better compensation effect.