Active Harmonic Filter
3P3W/3P4W Active harmonic filter
What is harmonic?
Harmonic is a signal whose frequency is a multiple of the frequency of a reference signal Harmonics are due to periodic distortion of the voltage or current waveform The distortion comes from nonlinear devices, principally loads.
The impact of inadequate power quality depends on the duration, intensity, and timing of the problem, along with how sensitive the attached devices are. Issues with power quality can lead to disruptions in operations, corruption and loss of data, errors in equipment controlled by computers, and excessive heating of electrical devices.
Causes of poor power quality
While it might be assumed that poor power quality mainly stems from external factors like weather and utility disruptions, research indicates that these contribute to only a minor fraction of electrical disturbances. In fact, a significant number of these issues originate internally or from nearby businesses within the same building or area. Common internal culprits include devices such as fax machines, copiers, air conditioners, elevators, and variable frequency drives.
The following conditions are indicators that a building may be at a higher risk for power quality problems, although they do not definitively predict issues:
● A history of power-related problems
● An electrical system that is poorly maintained
● Regular reliance on backup power systems
● Instances of lost or corrupted data
● Premature failures of equipment
● Frequent weather and utility interruptions
● Failure of surge protection devices
● A dense array of electronic devices
● Infrared surveys showing excessive heat due to current flow in grounding conductors and system neutrals
● Recurrent and unexplained equipment malfunctions, failures, tripped circuit breakers, or blown fuses
● Equipment overheating
These signs suggest an increased probability of encountering power quality issues.
Active Harmonic Filter (AHF) is a power electronic device designed to eliminate or significantly reduce harmonic currents generated by nonlinear loads in low-voltage distribution systems. The main purpose of this product design is to improve power quality and protect the power grid and electrical equipment from the impact of harmonic pollution.
Technical Specifications
| Operating voltage | 400V*±15% |
| Operating frequency | 50Hz±2.5 |
| Main circuit structure | 3p3w/3p4w |
| Rated capacity(Module) | 15A, 25A, 50A, 75A, 100A, 150A |
| Circuit topology | Three-level structure |
| Multi devices in parallel | Up to 12 sets can be connected in parallel |
| Response time | ≤5ms |
| Efficiency of single machine | ≥98% |
| Working mode | Harmonic compensation, reactive power compensation, three-phase load unbalance compensation. |
| Harmonic filtering | The device can filter out harmonics 2nd to 50th odd orders at the same time(Full), and specific order harmonics(between 2nd to 50th odd) can be filtered out by setting(selective) |
| Current limit | The compensating current is automatically limited within the rated current range. |
| Compensation effect (At sufficient capacity) | Total harmonic current distortion rate (THDi) ≤ 5%; Reactive power factor ≥0.99; Three-phase unbalance degree≤ 5%; |
| Display Interface | External 7” HMI or built-in HMI |
| Display status | Displayed in a data mode |
| Operations | Manual start, automatic start |
| Communication | RS485, Modbus communication protocol |
| Environment temperature | -20 ~ 55 ℃ (rated power output) |
| Storage temperature | -30～70℃ |
| Relative humidity | 95 % at a maximum, no condensation |
| Altitude | Below 1500 meters above sea level |
| Cooling requirements | Require well ventilation, and the air vent can be opened through the cabinet door, or a fan installed in the cabinet. |
Application scope
Widely used in industrial fields, such as chemical, metallurgical, manufacturing, data centers, hospitals, commercial buildings, and other places with a large number of nonlinear loads, it is of great significance to ensure electricity safety, stable operation, and meet relevant electricity quality standards.
Industrial automation production lines
In modern factories, variable frequency drives, rectifiers, and other nonlinear load devices are widely used, which generate a large amount of harmonic currents. Installing LV-AHF can effectively reduce the impact of these harmonics on the power grid, protect sensitive control equipment, improve production efficiency, and comply with power quality standards.
Distributed power generation system:Data center and IT facilities:
The UPS system, switching power supplies, and a large number of electrical equipment such as servers in the data center generate a large amount of harmonics, which affect the quality and reliability of power supply. By applying LV-AHF, voltage fluctuations and flicker caused by harmonics can be reduced, ensuring stable operation of critical loads.
Commercial buildings and office environments:
Lighting dimming systems, elevator drivers, and air conditioning systems in commercial buildings often contain nonlinear components, which may cause harmonic problems. LV-AHF can ensure the normal operation of these devices while improving the overall power quality of the building, reducing energy consumption and maintenance costs.
Railway and Rail Transit
In rail transit systems, electric train traction inverters are typical nonlinear loads that generate a large number of harmonics. The use of LV-AHF in the distribution system of stations or rolling stock depots can significantly reduce harmonic content, ensure rail transportation safety and reliable power supply.