One of Canada’s largest manufacturers of innovative and sustainable packaging products was facing multiple transformer failures and production stops due to power quality issues at one of its many sites. The manufacturer needed to find a way to eliminate these recurring problems and troublesome interruptions. Multiple studies on power quality were performed by different contractors. Comsys Partner, ADM Engineering, was one of the companies performing power studies and providing analysis report.
The challenge facing ADM was to determine what was causing the periodic failures in the main transformers and to recommend a reliable remedy. Following site measurements and subsequent analysis of the data captured by ADM and Comsys, the root of the problem was identified. The culprit was the resonance caused by the interaction between the natural resonant frequency of the power system, tuned capacitor banks, and nonlinear loads. Based on these findings, ADM was able to recommend ADF as the only viable solution to the site’s persisting problems.
ADF P300 – Active Harmonic Filters engineered and assembled by ADM using PPM300 modules.
The ADF solution has been operating successfully since January 2020, eliminating resonance and harmonics as well as providing near unity power factor. Cost savings alone have amounted to around CAD 30,000 per month by eliminating harmonics and correcting the power factor. Increased uptime and productivity provide even more value.
- Mill power outage frequency significantly reduced
- Oil cooled transformer runs much cooler and requires less frequent oil changes
- Significantly reduced running temperature of several transformers
- Reduced nuisance trips and blown fuses of 600V switchgear
- Reduced saturation of feeding transformers, reduces voltage variations to nominal values
Current THD – before & after installing ADF
Power Factor – before & after installing ADF
Machine drives system supply voltages before active filters installation
Machine drives system supply voltages after active filters installation
It is not only ABB and Schneider that release new, smaller Active Harmonic Filters. Comsys, a Swedish company specialized in Active Harmonic Filters presented their new ADF-P25 model at the SPS Nürnberg last November. We got a chat with Rickard Jacobson, Head of Sales and Marketing at Comsys.
“We see an increasing demand for smaller filters in applications such as datacenters and commercial buildings where harmonics is an increasing issue. We scaled down our current design to 30A but it offers all the functionality and robustness that you find in the larger industrialized versions. As this filters will be broadly utilizedused we have focused a lot on simplicity, plug and play, making it very easy to commission and operate. We offer the option of Sensorless control as well as WiFi to access a bigger user interface on a mobile device.
We think this can be a great entry offering as customers can test the solution without allocating too much funds. It fits well with larger HVAC systems and building technology in general.”
Comsys has released a application note explaining the detailed advantages of using central filtering of many drives rather than installing separate low harmonic drives. A central active harmonic filter is often the cheapest and most efficient answer to maintain code compliance.
Read the report here: Global-vs-Local-Compensation_Application_Note
Comsys has supplied Active Harmonic Filters to multiple offshore supply vessels. Bourbon Offshore, one of the biggest operators of offshore service vessels is using active filtering on their Evolution series of MPSVs. Filtering is employed on the main busbar to comply with class regulations. For a full report on the project and the result see here:
Active Harmonic Filters are becoming cheaper and very competitive compared to other active mitigation solutions such as Active Front End, which we explained here. In some applications that are not too dynamic, a passive harmonic filter makes perfect sense to reduce the investment. A combination of active and passive filters can be the best solution to reduce the investment cost while still being able to cope with dynamic loads. In such an application the passive harmonic filter focuses on the dominant harmonic component. This solution is currently used by for example the German auto industry in their production lines.
PQ Nosswitz, a German power quality solutions firm, devised a system to allow a flexible combination of active harmonic filters and passive harmonic filters to enable the most flexible and cost efficient solution for every project.
Active Filtering just got simpler with Sensorless Control
Comsys has released a new solution for controlling the Active Harmonic
Filter. The sensorless active filter control reduces the cost and
complexity of the system as it does not require any current transformer
In this case study they describe the retrofit on a small diesel
electric powered oil tanker, Fox Luna. The sensorless active filtering
approach is well equipped for protecting sensitive loads from dirty grids.
When the 32 MW Kville wind power station was being built in Sweden, the local grid owner Fortum was looking for alternatives for inductive compensation. The long underground cable length cause a dynamic capacitive reactive power problem that normally is compensated using a large MV inductor. The inductor is very large and costly device at these sizes and Fortum wished to investigate other alternatives.
Comsys used its extensive knowledge from MV applications in applying its liquid cooled low voltage Active Filter with a step up transformer to create a 2,5 MVA STATCOM solution to solve the problem. If applied correctly, an active technology is very compact and flexible enabling high availability. Comsys liquid cooled modular design offers a high degree of redundancy and availability as the modules can be operated individually.
A further complication was the requirement to measure at the PCC on the 130 kV level so the Low Voltage ADF STATCOM worked through two step-up transformers. After extensive simulations by Comsys, the system was designed and supplied through the turn key integrator Siemens.
The active filters where installed in an existing building and the step-up transformer was installed outside, saving valuable indoor space and requiring no additional transformer cooling.
The solution dynamically compensates the capacitive reactive power and keeps it in line with the utility’s requirement. Due to the STATCOM following the load dynamically and observing both voltage and current, optimal grid conditions are ensured during all operating conditions.
The investment cost was reported to be lower than using the customized inductor solution proving the competitiveness of small active STATCOM versus passive options.
The ADF P700 STATCOM is a perfect solution in a dynamic environment such as wind farms. It is as cost effective and compact as a passive solution but with superior performance.
AHF Reduces Flicker from Radiator Production
Today’s industry constantly faces new challenges. As the local community grows, large businesses with energy intensive production processes are faced with the challenge of reducing their effects on the grid. High flicker emission levels can potentially disturb other industries on the public grid.
The plant is a 55000 square meter radiator factory in Belgium, It consists of six production lines that in total can produce about 5000 radiators a day. The production process consists of presses, seam welding and spot welding. The process is inherently very energy demanding and so puts great demands on the power grid. These processes combined to create large voltage drops in the feeding substation with the result of too high Pst values. The problems at the plant caused flashing lights when the local utility company would connect other consumers to the same transformer.
The local utility company demanded that the Pst 95% value could not exceed 0,7. Measured values during 2009 showed tops in the Pst equivalent to 1,6. Achieving this goal was no small feat due to the rapidly fluctuating load, and the many different load patterns that could occur with such a high number of welding machines.
Active Harmonic Filters – the Solution
The market leading response time for the active harmonic filter was a necessity for the customer to reach the values that the utility company demanded. The system consists of six units, making it a total of 2,1 MVAr continous power to compensate for the voltage drops.
Installation of Active Harmonic Filters Creates Results
After installing the active harmonic filters, the plant has managed to keep their Pst value below 0,63, regardless of how many welding lines are run simultaneously. The reference values have been measured by external consultants and approved by the local utility. As a side effect of the lowered flicker value, the plant now also enjoys stabilized production environment.