Research on Underwater Constant High-Voltage DC Switching Technology for MCSEM

Area of Science:

• Marine geophysics
• Electrical engineering
• Power electronics

Background:

• Marine Controlled Source Electromagnetic (MCSEM) transmitters require high currents near the seabed.
• Three-phase alternating current (AC) transmission in MCSEM systems can cause three-phase imbalance, leading to excessive current and tow cable safety risks.

Purpose of the Study:

• To propose and analyze a novel underwater constant high-voltage direct-current (DC) switching scheme for MCSEM transmitters.
• To replace traditional AC transmission with DC transmission to enhance operational safety and efficiency.

Main Methods:

• Development of a simulation model to analyze the proposed DC switching scheme.
• Design of key hardware components: a DC switching inverter unit, a filter unit, and a step-down rectification unit.
• Utilization of insulated gate bipolar transistor (IGBT) modules and sinusoidal pulse width modulation (SPWM) for DC to AC conversion.

Main Results:

• The proposed scheme effectively converts 3000 V DC input to an adjustable 48.3-73.4 V DC output.
• Significant reduction in current on the tow cable was achieved.
• Fundamental avoidance of three-phase imbalance and AC inductive losses.

Conclusions:

• The developed DC switching scheme offers a safer alternative to AC transmission in MCSEM operations.
• This technology has the potential to reduce tow cable burnout incidents and improve overall MCSEM system safety.