Table of Contents
Power quality application: Beijing West Railway Station is very important
Beijing West Railway Station was opened in 1996 and expanded in 2000. It provides services for up to 400000 people every day. With an area of 510000 square meters, it is the largest railway station in Asia. This project is a typical power quality application of Enjoypowers in the transportation industry.
Ensuring the safety and energy conservation of Beijing West Railway Station is the focus of the operation and maintenance of the power system of Beijing West Railway Station.
Why is power quality so important?
In the power system operation and maintenance of Beijing West Railway Station, it is very important to ensure the power quality of the electrical system.
- The primary consideration of Beijing West Railway Station is to ensure the safe operation of the electrical system and reduce the risk of equipment failure or overheating;
- Good power quality ensures that the electrical system is more efficient. The daily power consumption of Beijing West Railway Station is very huge. Ensuring that the equipment operates with the best energy consumption can not only save electricity but also reduce the overall energy consumption, so as to reduce the carbon footprint.
What causes poor power quality?
- The load change of the locomotive traction system is not only fast but also violent
- A large number of nonlinear loads are increasing (including LED lights, UPS power supply, frequency converter, and other power electronic equipment)
- A large number of single-phase loads are increasing
- The above problems lead to serious power quality problems, including high harmonic, low power factor, and serious three-phase imbalance.
These problems will affect the normal operation of the control system and relay protection devices, and even cause problems such as false tripping, cause hidden dangers of social public safety, and increase energy loss.
How is power quality measured?
Enjoypowers use the power quality analyzer (low-frequency spectrum analyzer) to analyze the power quality of the electrical system in real-time. Its function is to provide the spectrum graph of AC voltage on the display screen.
Enjoypowers adopted the French CA8336 quality analyzer and provided customers with a power quality audit report
What is the difference between active and passive harmonic filters?
For the power quality problem of Beijing West Railway Station, customers can choose to use the active harmonic filter or passive harmonic filter to solve the harmonic problem.
The passive harmonic filter filters the current wave through the input reactor, output reactor, shunt reactor, and capacitor. They are simpler solutions for a single equipment project but are limited to a single and stable load.
An active harmonic filter(AHF) is a kind of harmonic compensation device, which can eliminate the harmonic damage of the current spectrum in real-time, and provide accurate compensation for the harmonic quality of the active load. It helps to comply with the international power quality standard IEEE 519.
AHF is larger than the passive harmonic filter. Although the AHF has space limitations, it can provide a higher level of power quality improvement:
- When the rated capacity of the filter is reached, the active harmonic filter will not be overloaded, while the passive harmonic filter may have overload risk.
- If the active harmonic filter is disabled, the motor whose power is being optimized will not be affected because the currency itself does not flow through the filter.
- The active harmonic filter can work with many variable speed drives. If the installation contains many nonlinear loads, the passive harmonic filter will not be able to perform effectively.
Beijing West Railway Station finally adopted our proposal to use AHF. Although the initial cost is a little higher, the AHF will be more effective in terms of use-value and full life cycle cost.
How can we improve power quality?
After analyzing the power quality problems of Beijing West Railway Station, Enjoypowers provided the power quality audit report and eight sets of 150A wall mounted Three-level AHF. AHF is installed on the low-voltage outgoing side of the transformer, and mitigates power quality problems like harmonics, low power factor, and imbalances, to ensure grid power quality and reliability.
How about the actual effect
Compared with the data before and after compensation, the harmonic treatment effect is remarkable:
| AHF | THDi（total） | THDi（5th） | THDi（7th） |
| Before compensation | 27% | 22% | 6.7% |
| After compensation | 4.5% | 5% | 2.9% |
After comparing the data before and after the AHF operation. After using our AHF for harmonic treatment, the total current distortion rate (THDi) of the Beijing west railway station power grid is reduced from 27% to 4.5%, and the effect is remarkable.
About Enjoypowers
Enjoypowers is the top 2 power quality supplier in China, providing OEM services for power quality products to more than 480 partners. Enjoypowers’ products have been successfully delivered in more than 20 countries。Enjoypowers Technology has a large number of power quality application cases around the world.
Selecting power quality products according to your specific requirements: Enjoypowers team is happy to assist you to select and calculate the appropriate AHF or module size and implement a power quality solution that perfectly meets your requirements.
For this, please send us your application data and contact me: [email protected], or connect with me on LinkedIn.