A utility-scale solar-plus-battery energy storage system (PV+BESS) that employs string power conversion systems (PCS), instead of centralized ones, offers several advantages, notably modularity.
Sineng Electric, the Chinese PV inverter and energy storage solution maker, has recently strengthened its string PCS product portfolio with its latest liquid-cooled 430 kW model. Suitable for a wide range of ESS application scenarios, this model can be characterized based on multiple key metrics – modularity & flexibility, performance, and safety & reliability.
Modularity & Flexibility
The new product’s modular design – featuring scalability and compatibility with battery containers exceeding 6 MWh – helps optimize the project’s Levelized Cost of Storage (LCOS) across a wide range of application scenarios. Notably, compared to its predecessors, the company claims the new model offers a power density increase of up to 130%, reducing the installation footprint by 20% for the same installed capacity. This translates to enhanced installation flexibility in space-constrained environments and reduced infrastructure and material costs, according to the company.
Performance
From a generation standpoint, the integration of liquid cooling technology and advanced power control algorithms into the PCS improves round-trip efficiency (RTE) – a key performance metric – by up to 0.2%, while also reducing auxiliary power consumption by as much as 30%. Additionally, the system’s cluster-level management boosts charge and discharge capacity by more than 7% compared to conventional systems, contributing to greater operational cost optimization throughout the product’s lifecycle.
In addition, the intelligent thermal management system – powered by liquid cooling – extends the product’s operational life to up to 25 years and enhances both charging and discharging efficiency. Beyond operational performance, features like cluster-level management and automated state-of-charge (SOC) calibration reduce maintenance costs by up to 50%, according to Sineng Electric. Furthermore, rapid replacement of the PCS in under 30 minutes significantly minimizes downtime, increasing system availability to as high as 99.5%.
The unit also features advanced grid-forming technology with seamless switching between on-grid and off-grid modes. This ensures robust grid resilience through multiple grid-interactive functions such as fault ride-through, grid inertia response, and primary frequency response. In the event of a blackout, the PCS can support a black start, contributing to grid stability.
Safety & Reliability
The company says the PCS is designed for resilience in harsh environmental conditions, featuring an IP66-rated enclosure and C5-level anti-corrosion protection. It maintains consistent performance across wide temperature ranges (–40°C to +60°C), at altitudes up to 5,000 meters, and in corrosive coastal regions. Regarding critical safety concerns – such as fire risks from DC-side short circuits – the PCS incorporates advanced protection features that limit DC short-circuit current to 10 kA, the company noted.
