Study on Magnetic Field Distribution Calculation and Protection of Dry-type Air Core Bridge Arm Reactor for VSC-HVDC System

As one of the most important main equipment of VSC-HVDC transmission system, the dry-type air core bridge arm reactor bears the AC and DC composite large current in operation. The strong AC and DC magnetic fields generated by bridge arm reactor in operation have a certain impact on the surrounding environment and the occupational safety of personnel. Based on the technical parameters of a bridge arm reactor, this paper establishes a multi enveloped magnetic field simulation model of the reactor, and carries out the DC and AC magnetic field simulation calculation of the reactor under the rated working condition, the DC temperature rise current working condition, the 50Hz temperature rise current working condition and the 100Hz rated current working condition, and compares the simulation results with the industry standard magnetic field limits. It is specified that the magnetic induction intensity under rated working condition and DC temperature rise current working condition shall not exceed the standard limit of DC magnetic field. Under 50Hz temperature rise current working condition, the power frequency magnetic induction intensity 1.8 m above the ground and 6.96 m along the reactor radial direction is less than the occupational exposure limit of
$\mathbf{1000}\ \mu \mathbf{T}$
, In addition, the requirements for safe movement distance of operation and maintenance personnel under the rated current condition of 100Hz are clarified, and the recommended measures for setting safety anti magnetic fence are put forward. The research results can provide technical guidance for the magnetic field protection of VSC-HVDC bridge arm reactor and worker.