Delta Active Harmonic (Power) Filter

APF Principle

Delta’s PQC Series APF is connected in parallel with non-linear loads, and uses one set of current transformers (CT) to detect the load current. It calculates each order harmonic current by FFT algorithms in its DSP microchips, and then generates a compensating current with the same amplitude but opposite phase angles to the detected harmonic current, which cancels out the original load harmonics.

The PQC series APF not only eliminates harmonic current from the load side, but it also mitigates harmonic voltage caused by harmonic currents. The APF system can also improve power factor (PF) and correct load imbalances in the power system.

Description

TECHNICAL SPECIFICATIONS

Mixed Fixed Type

Electrical Specification
Rated Voltage	AC 208 V, AC 400 V, AC 690 V
Input Voltage Range	AC 208 V: AC 166~250 V AC 400 V: AC 308~456 V AC 690 V: AC 384~880 V
Electric Connection	AC 208 V & 400 V: 3P4W, 3P3W AC 690 V: 3P3W
Rated Current per Module	AC 208 V: 50 A, 75 A, 100 A, 150 A AC 400 V: 30 A, 50 A, 75 A, 100 A, 150 A AC 690 V: 100 A
Rated Current per Cabinet	AC 208 V: 50~750 A (Module combination) AC 400 V: 30~750 A (Module combination) AC 690 V: 100~500 A (Module combination)
Rated Frequency	50(60) Hz ± 10%
Input Voltage THD Range	≤ 15%
Redundancy	Each module is an independent filtering system
Harmonic Elimination Range	2^nd~50^th order (Selectable)
Harmonic Filtering Degree	0~100% programmable per harmonic in Ampere value
Harmonic Filtering Performance	Filter up to 98% harmonics at rated load THDv < 3%, THDi < 5% after filtering
Reactive Power Compensation Capability	Both inductive and capacitive reactive power
Reactive Power Compensation Performance	Cosφ ≥ 0.99 after compensation (if the APF capacity is sufficient)
Imbalance Correction Capability	Mitigate negative and zero sequence
Full Response Time	< 10 ms
Instant Response Time	< 100 us
Thermal Loss	AC 208 V: ≤ 5% of APF rated capacity AC 400/690 V: ≤ 3% of APF rated capacity
Output Current Limitation	Automatic (100% rated capacity)
Parallel Expansion (System)	Up to 10 Racks (7 modules per cabinet)
MTBF	> 100,000 hours