Supporting the operation of an automated waste collection system

Segment background

Our customer operates an Automated Waste Collection System (AWCS) in Australia. AWCS utilizes vacuum fans and pipes to transfer waste from distributed disposal points to a collection station, where the waste is sorted and transferred to recycling. These fans must be high-powered to be able to create the vacuum and transfer the waste for long distances, which makes the overall process very energy intensive.

Challenges of the waste collection system

To be able to maintain an adequate vacuum in the piping of the waste collection system, Variable Frequency Drives (VFDs) are used to control the speed of the vacuum fans. When VFDs are used in this type of high-power application, they produce significant amounts of harmonics to the network, if suitable compensation is not used. The customer contacted our local partner Ampcontrol and asked them to install passive harmonic filters to five different vacuum fans in the system.
After thorough investigations and power quality measurements, it was discovered that a passive solution would not be suitable for this type of application due to its slow reaction time. Constant over- or under-compensating will lead to high capacitive reactive power spikes or lack of it when needed. This will in turn lead to reactive power charges in the electricity bill because the reactive power needs to be drawn from the network when the passive filter under-compensates the load. In addition, a typical passive filtering system has a limited ability to reduce harmonics and they do not cope well with unbalanced loads.

Our Merus^® Solution

A more suitable solution was proposed to the customer: Merus^® A2 – 200A Active Harmonic Filters installed to each of the two busbars of the main switchboard connected in a closed loop configuration. With Merus^® A2, dynamic compensation is utilized for the fast-fluctuating loads in the network. It filters out harmonics, compensates reactive power, and corrects phase imbalances. Compared to a passive filter, Merus^® A2 provides a faster, more redundant, and scalable solution with a smaller installation footprint.

Results after installation

After our partner installed and commissioned the Merus^® A2 – Active Harmonic Filters, the customer experienced a range of benefits. The THDi was significantly reduced from extremely high levels, ensuring the effective operation of their Automated Waste Collection System. Reduction in harmonic distortion can lead to improved energy efficiency and lower operating costs. Furthermore, the Merus^® A2 – Active Harmonic Filters enabled the customer to meet local power quality standards and avoid penalties that may be imposed for non-compliance.