Abstract: In view of the current and voltage faults that may exist in the operation of cable rewind, an intelligent cable rewind protection system is designed, which takes STM32F103RCT6 single-chip microcomputer control unit as the core and integrates the functions of collection, judgment, protection and inspection, so as to realize the reliable protection of cable rewind.Due to the traditional overcurrent protection method in cable roll cart appears not to conduct a comprehensive effective protection current failure, so the introduction of the basic theory of symmetrical component method as a protection to put car running current fault detection cable volume, by measuring the degree of over current runtime, zero sequence current, negative sequence component and low voltage and overvoltage, cable roll cart for short circuit fault protection, open phase protection, unbalanced three-phase fault protection, single-phase earth fault protection, two phase ground fault protection, under voltage fault protection and overvoltage protection.To collect to the voltage, current signal into a single chip can handle the single polarity of small signal, design the signal conditioning circuit, and design the protection system of software, including data collection and processing, data analysis and calculation, fault detection, protection action to perform, as well as the human-computer interaction part, realized with cable roll cart running state judgment and fault alarm function.The test results show that the protection device meets the protection requirements.