Solid-state Decoupler

The solid-state decoupler is a key device in cathodic protection and AC corrosion mitigation systems. Its core function is "DC-block / AC-pass": it blocks DC current (CP current, stray current) flowing between structures while allowing power-frequency induced AC, lightning and fault over-voltage to be quickly discharged to ground. It combines metal-oxide varistors (MOV) with solid-state switching elements (thyristor / SCR, rectifier bridge, etc.) and is an upgraded replacement for traditional polarization cells and spark gaps. Under normal conditions the device shows high impedance and has no effect on CP potential; when the AC voltage across its terminals exceeds the action threshold, it instantly conducts and dumps dangerous current to ground, then automatically returns to blocking state after the event.

Main applications: insulating joint protection, pipeline cross-bond decoupling, AC interference drainage, safe connection between pipelines and grounding grids / other metallic structures.

Key Technical Specifications

• DC blocking voltage±2 V (customizable up to ±10 V)
• AC action (turn-on) voltage≤ 1.5 V (power-frequency RMS)
• Rated continuous AC current30 A / 50 A / 100 A (selectable)
• AC short-time withstand (1 s)≥ 2 kA
• Lightning impulse current (8/20 μs)100 kA
• Fault current withstand (0.5 s)50 kA
• Response time< 25 ns (nanosecond-level, far faster than spark gap)
• Insulation resistance≥ 10⁹ Ω
• Operating temperature-40 °C to +70 °C
• Ingress protectionIP65 / IP68 (burial / EX-proof box)
• Housing materialStainless steel / engineering plastic
• ConnectionM10 stud terminal / direct cable lug

Key Features & Advantages

• DC-block & AC-pass, dual protection in one device: blocks DC to prevent CP current loss while passing AC for induced current drainage — solves two problems with a single device.
• Solid-state, arc-free, maintenance-free: pure solid-state structure, no mechanical contacts, no arc erosion, longer service life than spark gaps.
• Multi-layer protection in one: AC decoupling + lightning/over-voltage protection + DC isolation, can replace the "polarization cell + spark gap" combination.
• No interference with CP system: high insulation, low residual voltage, no effect on pipeline protection potential or CP current.
• Flexible & universal installation: fits insulating-joint parallel mounting, test posts, EX-proof boxes and direct burial.