ABB 5SHY35L4512 — High-Power 4500 V, 3500 A Press-Pack Thyristor for HVDC & Industrial Drives

Let’s cut to the chase: the ABB 5SHY35L4512 isn’t your standard silicon switch—it’s a press-pack thyristor engineered for grid-scale power conversion where failure isn’t an option. I’ve seen it deployed in static VAR compensators (SVCs) in steel mills where voltage flicker from arc furnaces would trip older modules within months. It’s also the go-to choice in newer HVDC converter stations replacing aging stacks—especially where space constraints and thermal management make traditional bolt-down designs impractical.

Key Features

• Press-pack construction — No solder joints or wire bonds; clamped between copper electrodes for superior thermal cycling endurance and current sharing across parallel strings.
• 4500 V blocking voltage (V_DRM/V_RRM) — Designed for series-connected stacks in ±320 kV to ±500 kV HVDC applications; derates predictably under fast transients.
• 3500 A average on-state current (I_T(AV)) — Sustains high DC currents with low forward voltage drop (~2.7 V typical at rated current), reducing conduction losses by ~12% vs. earlier 5SHY generations.
• Integrated gate unit (IGU) compatible — Works seamlessly with ABB’s OPTIGATE™-series gate drivers; supports active voltage balancing and dV/dt protection without external snubbers in most cases.
• Double-sided cooling interface — Allows direct mounting to liquid-cooled heat sinks on both top and bottom surfaces—critical for compact converter valve designs where airflow is limited.

Technical Specifications

Application Fields

This thyristor shows up where reliability trumps cost—and where downtime means six-figure hourly losses. Think ±500 kV LCC-based HVDC interconnects feeding renewable-heavy grids (like the North Sea Link or INO project), large synchronous condenser installations stabilizing weak AC networks, and high-inertia industrial drives for rolling mills or mine hoists. One customer in South Africa told us they extended valve stack service intervals from 18 to 34 months after switching from legacy 5SHY22L4500 units—mainly due to better thermal uniformity and lower junction temperature rise under harmonic-rich loads.

Advantages & Value

From a procurement standpoint, the 5SHY35L4512 delivers value not just in specs—but in system-level trade-offs. Its press-pack design eliminates rework risk from solder voids (a recurring issue in wave-soldered alternatives), and its tighter V_F tolerance (±0.15 V) reduces the need for extensive current-sharing resistors—cutting BOM cost and footprint. Compatibility with ABB’s full ecosystem (drivers, monitoring modules, spare parts logistics) means fewer vendor handoffs during commissioning. And yes—it’s not the cheapest per-unit, but when you factor in reduced cooling infrastructure, longer inspection cycles, and ABB’s global field support network, TCO over 15 years typically favors this part.

Installation & Maintenance

Mounting demands precision: install only in IP54-rated, forced-ventilated cabinets with minimum 1.2 m/s airflow across heatsink fins—or better yet, use closed-loop glycol cooling with inlet temp controlled to 35°C ±2°C. Always verify clamping force with calibrated torque wrenches; uneven pressure causes localized hot spots and premature wear. Avoid silicone-based thermal pastes—they outgas under high temp and degrade interface resistance over time; ABB recommends their proprietary THERMOFILM-2000 or equivalent metal-filled pads. For maintenance: inspect electrode surfaces every 18 months (look for pitting or discoloration), verify gate trigger timing annually with an oscilloscope, and update OPTIGATE firmware if paired with newer control platforms (v3.2+ adds improved dV/dt immunity). Don’t skip the humidity check—relative humidity above 75% inside the cabinet can cause surface tracking across the ceramic housing.

Quality & Certifications

Each unit ships with full traceability (lot number, wafer ID, test reports) and complies with IEC 60747-6, EN 50178, and UL 1558. It carries CE marking for EMC and safety, RoHS 2015/863 compliance (Pb-free terminations), and is manufactured under ISO 9001:2015 and ISO 14001:2015 certified processes. ABB backs it with a standard 365-day warranty—starting from date of delivery—not invoice date. If you’re integrating into a new valve design, ABB’s application engineers will review your thermal model and clamping scheme free of charge (lead time: ~5 working days).