Mathematical Model of Pole-to-ground DC Fault in Power Supply System of Twenty-four-pulse Diode Rectifier

Twenty-four-pulse diode rectifier (TFPDR) with high resistance grounding at neutral point has been widely used in various isolated power systems. Many diode conduction combinations, complex and short transient process make it hard to model the dynamic behavior of pole-to-ground (P-to-G) dc fault of TFPDR. To solve this problem, a large signal mathematical model of P-to-G dc fault in TFPDR is established, which is based on switching function law and harmonic balance principle. Through comparison between mathematical calculation and physical experiment, it is validated that the mathematical model is effective and can accurately reflect the transient behavior of P-to-G dc fault.