Homogeneous Mixture Management in Transformer Manufacturing

In medium-voltage epoxy cast-resin transformers, the mechanical strength of the windings, partial discharge performance, and long-term thermal stability are a direct result of the mineral filler ratio and homogeneity used within the epoxy resin. In these applications, the dried and sieved silica (quartz) powders commonly used as filler material play a critical role in the production process due to their high filler ratios (60–75%).

| Recipe Precision and Process-Focused System Design

In this project, VOLDE designed a turnkey powder raw material management system covering the entire process, aimed at incorporating the silica-based filler powder used in epoxy cast-resin MV transformer manufacturing into production in a stable, repeatable manner. Due to their low flowability, high abrasiveness, and moisture sensitivity, these fine silica-based powder raw materials cannot be reliably managed with manual or semi-automatic systems on transformer production lines. Dosing deviations in particular can lead to viscosity changes during casting and air voids inside the mold, putting product quality at risk.

The system architecture is structured based on the recipe accuracy, batch repeatability, and mixer feeding continuity that are critical in transformer manufacturing.

• The fine powder raw material is managed within a controlled, closed system starting from the big-bag feeding points
• The risk of clumping and foreign matter is eliminated before it can affect the casting recipe
• Weighing and feeding steps are carried out automatically, with a precision that matches the epoxy-filler ratio exactly

Approximately 700 kg of silica-based filler is prepared in a temperature-controlled, weighed mixer, achieving the flowability and homogeneous structure suited to the epoxy casting process, and made ready for mixer feeding.

| Multiple Mixer Feeding

The parallel operation of multiple mixers in epoxy cast-resin transformer manufacturing is critically important for production capacity and cycle time. In this system, the prepared powder filler mixture is transferred to the mixers via a vacuum conveying system, through specially selected rotary valves suited to abrasive materials.

• The vacuum conveying infrastructure is configured to provide balanced, uninterrupted feeding for 6 epoxy casting mixers
• Thanks to the cyclone and diverting-screw combination, independent, controlled filler feeding can be carried out for each mixer
• The filler quantity fed to each mixer is managed by the automation system on a recipe and batch basis

| SCADA Integration and Reporting

The entire system operates integrated with a PLC & SCADA infrastructure; all critical parameters of the epoxy casting process are made digitally traceable. Each production recipe is managed by the automation system on a batch basis, and the data generated throughout the process is recorded centrally.

Thanks to SCADA integration;

• The amount of silica filler used, weighing accuracy, and feeding times for each batch are recorded
• Mixer-based production data allows recipe compliance and deviations to be tracked retrospectively
• Root-cause analysis and quality improvement work are supported through alarm, warning, and process-stoppage records

This structure meets the traceability, documentation, and quality-continuity requirements of epoxy cast-resin transformer manufacturing, minimizing variables dependent on operator initiative and creating an auditable, repeatable production infrastructure.