The security and stability control devices used in power systems have lots of characteristics. It possesses， for instance， many models and complex function with very short manufacturing period; it needs higher accuracy and reliability， processes more data with faster speed in action， and have various modes of communication with the supervisory control system. The developed UFV-200 series devices using configurable method adopt the uniform hardware platform of 32 bits CPU structure， and equally important， the cascading modularization design on the software. Thus， the UFV-200 series devices are capable of meeting with the flexibility of the changeable structure and operation modes in power systems. In addition， the engineering application in fields of the devices has been described at length.