Product Overview

The ABB 5STP26N6500​ is a high-power phase control thyristor (SCR) from ABB Switzerland Ltd. Semiconductors’ 5STP series, engineered for line-commutated converter (LCC) and high-voltage AC/DC switching applications where blocking voltage, surge capability, and on-state efficiency must coexist at multi-megawatt scale. The model decodes as 5STP = 5STP phase-control family, 26 = 2600A-class current envelope, N = “N-type” ceramic press-pack housing, 6500 = 6500 V repetitive peak blocking (V_DRM/V_RRM). Delivering a maximum average on-state current I_T(AV)M of 2810 A at T_C = 70 °C (half-sine) and 4410 A RMS, with a non-repetitive surge rating I_TSM of 45 kA (10 ms) / 50 kA (8.3 ms), the ABB 5STP26N6500​ sits in the upper tier of the 5STP 26Nxx sub-family alongside the 26N6200 (6200 V) and 26N5800 (5800 V) siblings.

What distinguishes the ABB 5STP26N6500​ from generic high-current SCRs is ABB’s patented free-floating silicon technology combined with an interdigitated amplifying gate structure. The free-floating die is not rigidly bonded to the Mo/molybdenum carrier but allowed micro-movement under the 81–108 kN hydraulic clamping force, which equalizes stress across the 6500 V silicon and suppresses cosmic-ray-induced failure modes—a key reason the 5STP platform is qualified for HVDC converter valves with 30+ year design life. The amplifying gate ensures uniform turn-on across the entire cathode area even at the 250–500 A/μs di/dt rates the ABB 5STP26N6500​ is specified for, keeping local hot-spot formation below damaging thresholds during converter valve commutation.

Electrically, the ABB 5STP26N6500​ shows V_T0 = 1.12 V and r_T = 0.29 mΩ, translating to ~2.0 V at 3000 A on-state—among the lowest on-state loss figures in the 6500 V / 2800 A class. The device is packaged as a 35–35.6 mm thick ceramic press-pack (weight 2.9 kg) with 56 mm surface creepage and 22 mm air strike distance, designed for double-side cooled heatsink stacks where R_th(j-c) drops to 5.7 K/kW. Qualified applications span HVDC LCC valve arms, SVC (static VAR compensator) TCR branches, medium-voltage motor soft-starters, and traction converter inter-phase links—anywhere a 6500 V blocking, 2800 A+ continuous thyristor with 45 kA surge immunity is the correct device choice.

Technical Specifications

Main Features and Advantages

Patented free-floating silicon for long-term reliability.​ The ABB 5STP26N6500​ uses ABB’s signature free-floating die architecture, where the silicon pellet is mechanically decoupled from the molybdenum carrier via a compliant buffer layer. Under the 90 kN nominal clamping force of a converter valve stack, this prevents thermo-mechanical shear that would otherwise accumulate over decades of 50/60 Hz cycling. In HVDC LCC valves—where the ABB 5STP26N6500​ is a typical arm-level device—this translates to the 30+ year design life utility operators require without scheduled thyristor replacement. Cosmic-ray single-event turn-on (SETO) mitigation is also baked into the free-floating structure, a differentiator versus lower-grade press-pack SCRs that lack it.

Interdigitated amplifying gate for uniform turn-on.​ At 6500 V blocking and 3000 A+ on-state, non-uniform cathode turn-on creates localized current crowding that can kill a thyristor in one commutation. The ABB 5STP26N6500​ integrates an interdigitated amplifying gate that pre-injects current into distributed cathode segments before the main gate pulse arrives, ensuring the entire 2600 A-class die area conducts within microseconds. This is what allows the ABB 5STP26N6500​ to sustain 250 A/μs continuous di/dt (500 A/μs for 60-second bursts) without destructive filamentation—a spec most 6500 V competitors can’t match without derating.

Ultra-low on-state loss at the 6500 V tier.​ V_T0 = 1.12 V and r_T = 0.29 mΩ give the ABB 5STP26N6500​ roughly 2.0 V drop at 3000 A, or ~6 kW dissipation per device at full tilt. In a 12-pulse HVDC valve quadrant carrying dozens of ABB 5STP26N6500​ devices in series per arm, that V_T advantage compounds into hundreds of kilowatts saved at the converter level—directly improving station efficiency and reducing heatsink/cooling OPEX. For SVC TCR branches that spend most of their life partially conducting, the low r_T also flattens the loss-vs-current curve, reducing VAR-stage step discontinuity.

High dv/dt and surge headroom.​ The ABB 5STP26N6500​ is rated 3000 V/μs commutating dv/dt at 4340 V working (T_j = 125 °C), and 45 kA / 10 ms surge (50 kA / 8.3 ms). This matters in SVC TCR applications where capacitor-bank switching injects high dV/dt into the thyristor pair, and in HVDC valve commutating chops where reverse recovery overshoot rides on top of 6500 V. The ABB 5STP26N6500​ also specifies a turn-off time t_q ≤ 800 μs @ V_D ≤ 0.67·V_DRM, dv/dt = 20 V/μs, I_TRM = 3000 A—adequate margin for 50/60 Hz line-commutated designs without forced-commutation assistance.

Double-side cooling flexibility.​ The 5.7 K/kW R_th(j-c) in double-side cooled configuration (vs. 11.4 K/kW single-side) means the ABB 5STP26N6500​ can be stacked between two heatsinks in a valve wing or placed anode-up / cathode-up as the cabinet layout demands. The 56 mm creepage and 22 mm air strike on the ceramic envelope also satisfy pollution-degree-2 outdoor-valve-housing requirements without additional potting, keeping the ABB 5STP26N6500​ serviceable during valve-wing refurbishments.