Electric field equivalent method for AC/DC hybrid electric equipment adapted to digital twin with low latency

Abstract

• The equivalence of electric field is mainly related to the excitation source. • The 2D axisymmetric model under various excitations is constructed and verified. • This method can ensure the real-time and high fidelity in electric field digital twin technology. • A novel isolated power supply transformer in flexible DC transmission is introduced and the method is applied. Real-time synchronization and high fidelity are the most important features of the digital twin technology. When constructing the digital twin of power equipment in flexible DC transmission technology, the simulation analysis based on transient electric field is accurate, but the real-time is difficult to guarantee due to complex structure and various working conditions. In order to reduce the delay caused by the solution as much as possible, starting from the type of excitation source, an electric field equivalent method for AC/DC hybrid electric equipment adapted to digital twin with low latency is proposed: electrostatic field equivalent is used under power frequency AC or impulse voltage excitation, and constant electric field equivalent is used under typical DC voltage at the converter station. The method has been theoretically deduced in detail and verified by using a RC voltage divider model. The results show that the method proposed in this paper can shorten the solution time to 6.4% of the original, and ensure that the error after equivalence is within 5‱ . Finally the method is actually applied to the digital twin electric field analysis of a power supply transformer for 535 kV DC circuit breaker. The time required for solving is 40 min and 14 s. It can fully meet the demand of the dispatching department to update and calibrate the electric field once every hour and ensure safe and stable operation of equipment without corona.