Micro-Hydro Power Plant (MHPP) is one of popular renewable based power plants that appropriate to be installed in developing countries such as Indonesia due to its stability, efficient operation and economic point of view. Frequency stability of power plant systems refers to the ability of generator to maintain the steady frequency during and post faults and rapid dynamic load. In order to keep the stability of power system frequency from fluctuations, generating units change their power output automatically according to the change of the system frequency or load through balancing of the active power with the loads. To keep the stability frequency on MHPP, active power fast control is employed in this study and all the system of MHPP and the frequency control are carried out and simulated extensively using MATLAB/Simulink. With the active power control through fast valving mechanism using HSVC method, duration of stability frequency response is faster compared to the system without fast control.

Critical infrastructures are vital assets for the public safety, economic welfare and national security of countries. Cyber systems are used extensively to monitor and control critical infrastructures. A number of infrastructures are connected to the internet via. corporate networks. Cyber security is therefore, an important item of the national security agenda of a country. These systems will empower our critical infrastructure and have the potential to significantly impact our daily lives as they form the basis for emerging and future smart services. On the other hand, the increased use of CPS brings more threats that could have major consequences for users but advances in technology make it necessary to develop new threats will continue to be exploited and cyber attacks will continue to emerge, hence, the need for new methods to protect CPS. This study introduces a novel framework for understanding cyber attacks and the related risks of multi elements, multi-layered to cyber-physical systems. The longer-term goal is to use the framework as a means to reduce cyber-physical system security properties and to enumerate the principles for designing systems that are resilient to cyber attacks and analysis of the security issues at the various layers of CPS architecture, risk assessment and techniques for securing CPS. Finally, challenges and possible solutions are presented and discussed.