Power quality problems in schools
With the continuous introduction of modern teaching and advanced teaching methods of electronic libraries, the continuous improvement of school conditions such as intelligent water supply and drainage, variable frequency air conditioners, and elevator transmission systems, as well as the continuous energy-saving transformation of lighting systems, the external devices in schools are becoming more and more burdensome. The use of these external power electronic devices will bring harmonic pollution, increase the reactive power of the system, cause low power factors, cause current imbalance and other power quality problems, and have an incremental impact and dissolution on the power quality of the harmonic system. By controlling harmonics, the stability of the harmonic system operation can be effectively improved, the life of teaching equipment and power equipment can be extended, the failure rate can be reduced, and the safety deficiencies of the system can be reduced.
Where do school harmonics come from?
The school's electrical load is mainly lighting. Most of the school's lighting equipment uses fluorescent lamps, which will produce higher third-order harmonics. In addition, the school also uses many air conditioners and elevators. Air conditioners and elevators use frequency conversion devices, which will produce many harmonics, mainly 5th and 7th harmonics. Secondly, the school has an information center multimedia center, computers and UPS power supplies. The computer's switching power supply and UPS are harmonic sources, which will produce a large number of 3rd, 5th, and 7th harmonics. In addition, colleges and universities have laboratory buildings, which have various experimental equipment. There are nonlinear devices in this experimental equipment, which will produce low-order harmonics, mainly 5th and 7th harmonics.
Pain points of school harmonics
Grid harmonics will reduce the power quality of the school's power grid, seriously affect the reliability of power supply, and may cause the system to be powered off for no reason in severe cases. Due to the existence of harmonic currents, the load current increases, occupies the transformer capacity, and reduces the system utilization rate. In addition, the temperature rise of the system transformer and transmission line increases, the service life of the equipment is reduced, and there is a safety hazard of electrical fire. Schools are densely populated, and the requirements for power quality and power safety are very high. Therefore, if there are harmonies in the distribution system, timely attention and treatment are required.
School Harmonic Treatment Plan
The harmonics generated by the school are mainly 3rd, 5th, and 7th low-order harmonics, and the load current is small, and the harmonic current value is not large. Shanghai Xixing Technology EasyPQ-SVG series static VAR generator can compensate for reactive power, adjust the imbalance of three-phase current, and can also treat 2~13th harmonics, comprehensively improving the power quality of the school's distribution system.
For teaching buildings and dormitory buildings, a centralized treatment plan can be adopted, and SVG can be added to the power trunk line of the distribution system for compensation and filtering. For experimental buildings, libraries, and information centers, small-capacity SVG can be added to the distribution box on the floor for on-site compensation and treatment.
