The invention provides a power supply redundancy 
system of a high-temperature dust removal and denitration 
system, an operation method of the power supply redundancy 
system, and a method for maintaining and detecting a high-
voltage electric field by using the power supply redundancy system, belonging to the technical field of dust removal of 
flue gas. The invention aims to overcome the problem that the reliability of a high-temperature dust removal and denitration system is influenced after a high-
voltage power supply of a high-temperature dust remover fails in the prior art. The system comprises a preheater, a 
flue gas modulation system, a high-temperature dust remover and an SCR denitration system, wherein the preheater, the 
flue gas modulation system, the high-temperature dust remover and the SCR denitration system are sequentially connected through pipelines; the high-temperature dust remover comprises a first high-
voltage electric field and a second high-voltage 
electric field; the first high-voltage power supply supplies power to the first high-voltage electric field through a first high-voltage switching device; the second high-voltage power supply supplies power to the second high-voltage electric field through a second high-voltage switching device; and a high-voltage 
communication device for electrically connecting the first high-voltage switching device and the second high-voltage switching device is arranged between the first high-voltage switching device and the second high-voltage switching device.