The invention discloses a method and a
system, and relates to the technical field of
relay protection. The method comprises the following steps of: acquiring electrical data of a synchronous parallel point, inputting two paths of
voltage data, setting a setting value, judging the state of the synchronous parallel point based on the input two paths of
voltage data, and performing manual intervention on asynchronous protection after asynchronous protection quits. According to the grid-connected asynchronous protection method provided by the invention, the state of a synchronous parallel point can be accurately judged by comparing the output two paths of
voltage data with the setting
value set in the device, the fault condition and position of a
power grid can be more accurately judged, the abnormal state can be quickly detected, a
circuit breaker can be timely pulled open, and the safety of the
power grid is ensured. The method prevents generation of strong
impact current, prevents burning loss of equipment, effectively protects electrical primary equipment, compares timing time with a setting
value set by a
system, ensures that non-synchronous protection does not continue to work due to misoperation, and enables an
electric power system to recover to normal more quickly. According to the invention, better effects are achieved in the aspects of preventing electric appliance
burnout and
response time.