This design is and switches on the optimum matching again to the line protection the theory and the method research. Between paper utilization many kinds of methods improve the line protection and switch on again the coordination: Through inquires each kind of material and the data confirmed that reduces switches on the time limit is achievable again; At the same time, this article according to the constant area rule principle computation to obtain best switches on the time again, the guarantee system is stable; In the tradition switches on again the foundation, analyzes auto-adapted thoroughly switches on the technology again, differentiates the breakdown using the voltage criterion the nature, before superposition did the diagnosis whether instant nature, decide that again switches on the signal the transmission or not; About will divide the floodgate time selection aspect to use the Fourier algorithm to direct current and the AC component separation, will realize a short circuit zero predict that if will be able to achieve this algorithm and computer's high speed computing power union the short circuit undercurrent a minute floodgate, guarantee electrical power system's stability.
key word: Switches on the time limit again, a short-circuit current zero predict that switches on again auto-adapted, switches on again best