Methodology for Optimal Use of Various Voltage Control Devices in Smart Transmission Grid

Modern transmission network implies classic generation units, which are continuously subjected to decommissioning, growing power of renewable energy sources with low inertia, intermittent drive and installation of smart control, monitoring and protection devices. In such an energy mix, system operators are faced with a disturbed voltage profile that becomes the rule, not the exception. This requires the improvement of classical methods of voltage control by installing new devices, new voltage control systems and the activation of renewable energy sources in the control functions. In this paper, a methodology of optimal use of control devices depending on their time constants and control quantity is proposed. The methodology is based on the maintaining of the voltage profile within the allowed limits, and the minimization of the operation of the voltage control device with fast response during a long-term disturbed voltage profile.