Aimed at the applied limitations of traditional spare power automatic switchover（SPAS） for conversional substation in chain-mode power grid，a new technology of SPAS for area network is studied. The basic principle and procedure is also discussed while the key points are analyzed. Through demonstrated the cooperation relationship with traditional SPAS， auto-reclosing， security automation device and small power source etc， and considered a series of blocking conditions for power grid security， it is fully convinced that the application of SPAS technology for area network in smart grid is necessary and feasible. The test technology and approach under different channel environments in the laboratory and substation as well as the action time-limit of the area SPAS logic strategy are both given. While the potential risks of the area SPAS are analyzed， the reasonable improvement measures under the current grid communication technology conditions are given.This work is supported by Power Grid Automation Key Laboratory of China South Grid（No. K-GD2011-363）.