Active Harmonic Filters (AHF), also known as Active Harmonic Filter (AHF), help maintain clean and stable power by detecting and canceling harmonic currents in real time. Harmonics are unwanted distortions generated by non-linear loads such as variable frequency drives, welding systems, and computer equipment. The filters continuously monitor the current, analyze the harmonic content, and inject a compensating current of equal magnitude and opposite phase to neutralize distortion within the network. Besides harmonic mitigation, these filters also improve power factor and enhance voltage stability through dynamic reactive power compensation. They are widely used in industrial facilities, data centers, and commercial buildings where high power quality is essential for reliable and energy-efficient operation.
| General | Product type | Active Harmonic Filter (AHF) | |||||
| Rated capacity | 30A | 50A | 75A | 100A | 150A | 200A | |
| Operating voltage | Selectable 1. 400V (-20% to 20%) 2. 220V (-15% to 15%) 3. 690V (-30% to 15%, only for 100A) | ||||||
| Operating frequency | 50/60Hz ±5Hz | ||||||
| Wiring method | Selectable 1. Three-phase, three-wire 2. Three-phase, four-wire | ||||||
| Current sampling position | Selectable 1. Load side 2. Grid side | ||||||
| Parallel operation | Up to 12 units in parallel | ||||||
| Cooling method | Intelligent forced air cooling | ||||||
| General | Filter range | 2nd to 50th | |||||
| THDi (Total Harmonic Distortion) | < 5% | ||||||
| Three-phase unbalance protection | Supported | ||||||
| Instantaneous response time | < 50μs | ||||||
| Full response time | < 10ms | ||||||
| Noise level | < 65dB | ||||||
| Protection functions | Self-diagnosis and multiple protection features including over-voltage, under-voltage, frequency anomaly, over-temperature, over-current, short-circuit, phase-loss, DC bus over-voltage, DC bus under-voltage, IGBT fault, and inverter bridge reverse protection | ||||||
| Communication & Control | Extended functions | 10-channel TSC interface, capable of operating in combination with TSC/TSF | |||||
| Communication interface | RS485 port | ||||||
| Communication protocol | Selectable 1. Electricity master protocol 2. Modbus protocol 3. TCP/IP protocol | ||||||
| Display information | Displays grid parameters such as voltage, current, power, and harmonics | ||||||
| Monitoring method | Selectable 1. Independent module monitoring 2. Centralized module monitoring | ||||||
| Operating environment | Ambient temperature | -20℃ to 45℃ | |||||
| Relative humidity | ≤95%, non-condensing | ||||||
| Altitude | ≤1500m (for every 100m above 1500m, rated power decreases by 1%) | ||||||
| Enclosure protection level | IP20 as standard (higher protection levels are customizable upon request) | ||||||
| Installation | Selectable 1. Wall-mounted (modular) 2. Rack-mounted (modular) 3. Cabinet type (integrated) | ||||||
| Wiring method | Selectable 1. Bottom entry 2. Top entry | ||||||
Low-voltage APFs (also known as AHFs) are recommended. They filter 3rd–25th order harmonics, protecting sensitive equipment such as UPS units and precision instruments, and helping reduce failures caused by voltage distortion.
These filters typically target low- to mid-frequency harmonics generated by non-linear loads, effectively removing 3rd, 5th, 7th, 11th, and 13th order harmonics, and up to the 25th in complex systems.
Yes. In addition to harmonic suppression, they provide dynamic reactive power compensation, which improves power factor, stabilizes voltage, and reduces energy losses in the network.
Founded in 1995, Shanghai Wenlida develops and manufactures advanced voltage regulation and power quality equipment designed to maintain stable grid voltage levels, and ensure efficient and reliable operation of industrial and utility power systems.
