The electrical equipment of sewage treatment plants mainly includes pumps, agitators, blowers and other loads. Fans and pumps generally require frequency conversion, but the frequency converter is a particularly large harmonic source, so it will bring serious harmonic pollution and harmonic interference to the system, affect the work of the system, and often burn out electrical components. At the same time, there are also many power electronic components in the system, such as UPS, switching power supply, etc., which are important harmonic sources.

Load analysis

Water treatment plant has frequency converters, large air conditioning systems, ventilation equipment, these equipment frequency conversion mechanisms, control components are typical nonlinear load, the resulting harmonics flow into the power distribution system, pollute the power grid, not only will have a potential impact on reactive power compensation equipment but also affect the normal operation of various electrical equipment, reduce system efficiency, increase power costs. Reducing the service life of other electrical equipment has a significant impact on the safe and reliable operation of power distribution systems. At present, the power supply quality is difficult to meet the requirements of safety and stability, so harmonics is the main power quality problem.

Harmonic characteristics

The main electricity load of the water treatment plant is a three-phase motor, accounting for more than 90% of the total electricity load. The main harmonic source of the three-phase motor load is the frequency converter, and the frequency converter in the water treatment industry is mainly 380V and 6kV, 10kV frequency converter. The 380V inverter is basically 6 pulsation rectification, and the harmonic component produced is mainly 5th and 7th harmonics.

Solution

In order to ensure the normal water supply of residents, sewage treatment plants generally need to install BW-APF active power filters to control harmonics.

Governance benefits

1. Eliminate the harm caused by harmonics to production equipment and finished products, reduce accidents caused by electrical hidden dangers caused by harmonics, and extend the service life of various types of electrical equipment;

2. Provide power supply security and improve power quality;

3. Improve the utilization rate of equipment, and reduce the total operating current by compensating for reactive power and harmonic suppression;

4. Through compensation, eliminate the imbalance phenomenon and stabilize the 400V bus voltage;

5. Energy saving and consumption reduction, reduce the loss on transformers and lines.