The invention discloses a self-adaptive selective leakage 
protection system and method for a mine low-
voltage electric network. The 
system comprises a 
microcontroller module, double 
Ethernet communication circuit modules, an A / D (Analog-to-Digital) conversion circuit module, a leakage testing circuit module, a key operation circuit module, a 
noise elimination and filter circuit module, an 
electric network voltage and zero sequence 
voltage transmission circuit module, a plurality of 
branch zero sequence current transmission circuit modules, a 
liquid crystal display circuit module and a leakage 
tripping output circuit module. The method comprises the following steps: firstly, 
signal acquisition; secondly, 
signal collection, storage, analysis and 
processing; thirdly, manual 
leakage test existence judgment; fourthly, manual 
leakage test failure judgment and judged result output; fifthly, insulation parameter measurement and storage; sixthly, 
electric network leakage judgment; and seventhly, electric network leakage judged result output and leakage protection. The self-adaptive selective leakage 
protection system is novel and reasonable in design, strong in self-adaptability for different network structures of a mine power supply 
system, high in leakage detecting speed, reliable and accurate in action and high in popularization and application values.