Harmonic mitigation: Invest less and save more! The Danfoss masterclass solution for harmonic mitigation is a simple space and cost-saving design that increases efficiency to provide long-term energy savings and troublefree operation. How an advanced active filter works – simply and reliably An active filter works in a similar way to that which noise cancelling headphones filter out extraneous sound. Using external current transformers, the active filter monitors the supply current, including any distortion. From this signal, the control system identifies the required compensation and creates a switching pattern for the IGBT switches. This creates a low impedance path in the filter and harmonics flow into the filter instead of proceeding in the direction of the power supply. By cancelling out the harmonic current distortion almost completely, voltage distortion of the transformer or generator is no longer a concern. The filter carries out its current evaluation and cancellation continuously so that plant load variations, second-to-second or day-to-day, make no difference to the active filter’s performance. Meeting new standards Efficient harmonic mitigation protects electronics and increases system efficiency. The prescribed standard for harmonics mitigation is specified, for example in the IEEE-519 Guide, as limits for the harmonic voltage distortion and current waveforms that may exist in the system to minimize interference between electrical equipment. The latest update to this guide (2014) focuses on keeping down costs and on maintaining the voltage THD within acceptable limits at the Point of Common Coupling – defined as the interface between sources and loads. The Danfoss masterclass solution for harmonic mitigation is developed to meet the standards specified, for example in the IEEE-519 2014 Guide. Minimizing costs using advanced active filters Danfoss offers solutions to harmonics mitigation based on either active front end or passive filter, which may be appropriate in some applications. But to achieve the ambition of ensuring the necessary harmonics mitigation, while minimizing cost and energy consumption, most applications will benefit from our central solution using advanced active filter (AAF) technology; It takes up less space It costs less to install It uses less energy in operation It reduces heat loss It ensures higher uptime Use less energy with central advanced active filter (AAF) mitigation Our central advanced active filter solution encompasses up to 50 drives, ensuring harmonic noise is kept under 3% on all AC drives in the system. Connected in parallel and working in a similar way to noise cancellation headphones, advanced active filters are only active whenever necessary to maintain this level. This saves a lot of energy in comparison with Active Front End (AFE), installed in the drive itself, and requiring a voltage boost of approximately 10%. Minimizing heat loss for maximum installed efficiency The Danfoss master class design for harmonics mitigation combines AAF technology with our unique backchannel cooling concept to achieve a 50% reduction in heat loss in the system, compared to a traditional AFE setup. A future proof solution An upcoming amendment to the IEEE-519 Guide is very likely to include demands for harmonic components of order greater than the 50th. Already in the 2014 guide it states that “Harmonic components of order greater than 50 may be included in THD and TDD when necessary.”With the Danfoss AAF solution you are prepared for this, as high-order harmonic issues are already solved. 16 Danfoss Drives · DKDD.PB.202.A8.02 | Content |
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