Conventional energy grids growing in time have become complex, inefficient and expensive to operate and use. They are critical because of providing the whole energy needs of the technologies required for our modern life but also cumbersome entities. "Smarting" the grids by automating, facilitating the troubleshooting and productivity analysis with the help of information technologies infrastructure, reinforcing the controls, charging the services in details makes it possible to administrate efficiently and provide high level quality services. But, evolving cyber threats against the grids has addressed the security aspect again. This paper summarizes the inevitable strategic cyber security approach to be demonstrated against cyber threats and attacks exploiting the vulnerabilities of the smart grids that are one of the cyber-physical systems in critical infrastructures of many national cyber security strategies.