Description
Application Scenarios:
A Nordic steel service center operates a 90 MVA electric arc furnace that was causing 6–8% voltage flicker on the regional grid, triggering utility penalty tariffs. The plant‘s static VAR compensator used a thyristor-controlled reactor leg with twelve 5STP18H4200 devices in series per phase. After sixteen years of two-shift melting, one phase began misfiring intermittently during high di/dt transients. The maintenance team pulled the suspect thyristor, curve-traced it, and discovered the threshold voltage had drifted from 0.96 V to approximately 1.18 V—classic signs of silicon wear after roughly 120,000 thermal cycles. Swapping all twelve pieces in that phase restored clean phase-angle control, and grid flicker dropped to 2.4% within the same shift. The press-pack mounting meant the swap was simply unbolting the water-cooled heatsink clamps, lifting the disc, dropping in the replacement, re-torquing to specification, and bleeding the cooling loop—no solder, no bonded leads, no busbar rework .
Parameter:
| Parameter | Value/Description |
|---|---|
| Product Model | 5STP18H4200 |
| Manufacturer | ABB / Hitachi Energy |
| Product Category | Phase Control Thyristor (PCT) |
| Max Repetitive Blocking Voltage | 4200 V (VDRM/VRRM) |
| Average On-State Current | 2075 A @ Tc = 70°C |
| Max Load Current (RMS) | 3.4 kA |
| Max Forward Impulse Current | 32 kA |
| Gate Trigger Current (Igt) | 400 mA |
| Threshold Voltage (VTO) | 0.96 V typical |
| Slope Resistance | 0.285 mΩ typical |
| Turn-Off Time (tq) | 600 µs |
| Body Dimensions | Ø102 mm / Ø63 mm contact |
| Mounting Method | Press-Pack (compression) |
| Weight | Approximately 900 g |
