I. Introduction
II. Overview of Smart Grid
2.1. Smart Grids' Features
2.2. Smart Grid Applications
III. Smart Grids Architecture
3.1. Smart Grids Communication Technologies
3.2. Smart Grids Protocols
IV. Security of Smart Grids
4.1. A Classification of Cyber-Attacks in Smart Grid
4.2. Cyber-Attacks in Smart Grids
4.3. Detection Techniques of Cyber-Attacks on Smart Grids
4.4. Countermeasures in Smart Grids
4.5. Comparison and Discussion
V. Conclusion