Transient Voltage Management in Offshore Wind Power Systems

Transient voltage events in offshore wind power systems arise primarily from switching operations, cable energisation and de-energisation, and fault clearance. These events manifest as rapid overvoltages with high amplitude and steep waveform fronts, posing a threat to wind turbine transformers, submarine cable insulation and protection devices. Management of these overvoltages relies on a combination of accurate transient modelling, real-time monitoring and application of mitigation devices such as snubber circuits, surge arresters, pre-insertion resistors and damping reactors. Recent advances have focused on capturing the microscopic dielectric recovery processes of vacuum circuit breakers, refining high-frequency component models for submarine cables and transformer windings, and optimising the coordination of suppression schemes across complex collector grid topologies. Effective transient voltage management is essential to ensure grid code compliance, prolong equipment lifetime and enable stable large-scale integration of offshore wind capacity into national transmission networks.

Research from Nature Portfolio

A recent evaluation of overvoltage suppression measures tested four commonly deployed schemes—R–L smart choke, R–C snubber circuit, surge capacitor and pre-insertion resistor (PIR)—across radial, single- and double-ring, and star collector grid topologies. Using an SF6 circuit breaker model based on a real offshore wind farm, the study confirmed that the R–L smart choke consistently delivered the highest overvoltage reduction (62–84 %), followed by PIR (33–67 %), R–C snubbers (8–25 %) and surge capacitors (4–15 %). Importantly, grid topology variations did not alter the ranking of effectiveness, underscoring the smart choke’s universal applicability in diverse offshore configurations.

Transient Voltage Management in Offshore Wind Power Systems publication trend

The graph below shows the total number of articles in transient voltage management in offshore wind power systems across all publications each year (not limited to Nature Index journals).

Technical terms

Transient overvoltage (TOV): A short-duration voltage spike occurring during switching or fault events, characterised by high amplitude and steep front.

SF6 circuit breaker: A high-voltage switching device using sulphur hexafluoride gas to quench arcs and interrupt fault currents.

R–L smart choke: A damping inductor with tailored resistance used to attenuate high-frequency transient components.

Pre-insertion resistor (PIR): A resistor temporarily inserted into the circuit at breaker closing to limit current and voltage stress.

Dielectric strength recovery: The process by which a breaker’s insulating gap regains its dielectric withstand capability after arc extinction.

Surge arrester: A protective device that diverts or clamps excessive transient voltages to ground, safeguarding equipment insulation.

Ferroresonance: A nonlinear resonance phenomenon involving transformer magnetising inductance and system capacitance, leading to unpredictable overvoltages.

References

1. Evaluation of the efficacy of transient overvoltages suppression measures in different wind farm topologies using SF6 circuit breaker. Scientific Reports (2023).
2. Simulation and Protection of Reignition Overvoltage in Wind Farm Considering Microscopic Dielectric Recovery Process of Vacuum Circuit Breaker. Energies (2023).
3. Optimization-Based Mitigation Techniques of the Temporary Overvoltage in Large Offshore Wind Farm. IEEE Access (2023).