This advanced microprocessor controlled power quality filter has been designed to solve harmonic and neutral current related problems in commercial buildings and small industrial applications:
The PQFS has the versatility to work equally well with three-phase, three-wire or three-phase, four-wire systems. It is ideally suited for smaller and medium loads where the equipment is connected between line and neutral or line and line or a mix of all these types.
The feature of load balancing between line and neutral, thought to be unique, enables the PQFS to reduce even the fundamental frequency current in the neutral, normally present due to unbalanced loading between phases, as well as filtering the harmonic currents from the line and neutral conductors.
Standard PQF features:
The PQFS is packed with the standard features of the PQF range; including individual targeting of harmonics combined with curve setting functionality and closed loop control. This allows achievement of standards such as G5/4, IEEE 519 etc. with optimal filter rating. Reactive power compensation enables the load power factor to be increased to the desired level, while balancing loads between phases helps in reducing the negative sequence current. Other features include dynamic low loss control system, the highly advanced PQF-Manager user interface with network analysis capability, Modbus communication capability, real time stamp of events, parallel operation of units without derating, easy commissioning etc.
In common with the existing filters in the PQF range (PQFI, PQFM, PQFK) the PQFS is modular in design. On-site extensions can be done easily by adding slave units in parallel to the master unit. The PQFS is suitable for direct connection up to 415V and is available in three power ranges: 60, 45 and 30 ARMS per unit.
ABB PQF active filter concept:
The increasing use of non-linear loads in all types of industrial and commercial applications has resulted in the introduction of potentially harmful harmonics into the power network that can lead to overheating of cables, motors and transformers, damage to sensitive equipment, tripping of circuit breakers and blowing of fuses as well as premature ageing of the installation. ABB PQF active filters provide a reliable and cost-effective solution to this problem by continuously monitoring the current in real time to determine what harmonics are present and then injecting harmonic currents in the network with exactly the opposite phase to the components that are to be filtered. The two harmonics effectively cancel each other out so that the feeding transformer sees a clean sine wave.
ABB PQF active filters are factory assembled and tested, ready to install and use at site. They have a modular construction, which allows easy extension to cater for future load growth. There is also no need to apply a de-rating factor when PQF units are coupled in parallel, which makes it feasible to achieve a high rating within a small footprint. Since the PQF does not operate according to the conventional low harmonic impedance principle employed by passive filters it remains unaffected by changes in network parameters and cannot be overloaded.
The picture shows the new ABB PQFS compact wall-mounting active filter unit.