- Client: New‑build power station (South Korea)
- Cooling Power: 2 × 1300 kW (redundant) coupled pump/treatment and expansion skids paired with stainless steel air blast dry coolers
- Temperature Range: Ambient -20°C to +50°C
- Conductivity: < 0.1 µS/cm across converter valves
- Dissolved Oxygen: ppb range using GRE designed degassers
- System components: Two pump skids, two expansion skids, two scrubbing circuits, 10 air‑blast dry coolers
- Interesting System features: Fully redundant skids (all components, including instrumentation, pumps and PLCs; modular layout to suit space; on‑site installation and test
Power electronics for STATCOM/HVDC demand extremely stable, low‑conductivity cooling to avoid leakage currents and galvanic effects across valve stacks. GRE engineered, manufactured, shipped, installed and tested two fully redundant DI cooling systems, designed such that no single component outage compromises capacity. Each equipment train includes run-standby process pumps on VFDs, duplex strainers and duty/standby resin polishers. Control is based on dual PLCs with segmented PROFINET networks; IO is distributed to reduce single‑point failures and ease maintenance.
The treatment train uses mixed‑bed ion exchange (polishing) and 0.2 μm filtration, and custom degassing for ppb‑level oxygen. To withstand DI water’s higher solvency, all wetted metallic parts are 316L stainless with all assemblies passivated post fabrication; heat exchangers are fully welded stainless (no copper brazing). All piping spools are orbitally welded to approved standards.
Each system was shipped as three compact skids to navigate plant access constraints, then bolted together on site. Ten air‑blast coolers provide primary heat rejection with N+1 fan redundancy and seasonal control. Continuous trending of conductivity, dp across filters, valve position and pump speed enables precise monitoring predictive maintenance. Commissioning included full functional testing, trip matrix verification and operator training.
GRE also provided a full 2-year spares package for the systems.