Modeling of Secondary Voltage Regulation for 24-hour load flow and dynamic simulation for coordinated voltage control application

Effective and efficient management of voltage and reactive power devices is one of the most challenging tasks in power grid operation especially in a large power grid. A Coordinated Voltage Control (CVC) approach that consists of primary voltage control (PVR), secondary voltage control (SVR) and tertiary voltage control (TVR) is the most effective solutions for reactive power and voltage control. CVC refers to an approach in which secondary voltage control or regulations (SVR) is carried out automatically using a control system that would coordinate the various voltage control equipment to achieve a desired voltage at a pilot node in the system. There are various SVR model has been deployed by power utility for their CVC implementation. In Tenaga Nasional Berhad (TNB) power system, coordinated voltage control system is yet to be implemented, but improvement in the approach and methods to performing secondary voltage control are desirable since it could enhance system performance in terms of reliability and security as well as system losses. To demonstrate the capabilities of SVR within TNB grid system, a preliminary studies has been carried out, where new SVR dynamic model has been developed suitable for TNB CVC system implementation. Since voltage control is a real time activity that repeats itself on a daily basis, it was agreed that a more effective approach to study the process of SVR would be to perform simulations on a 24-hour basis where at defined times during the day the SVR would be applied. Two simulations approach has been carried: 24-hour load flow and 24-hour dynamic simulation, both implemented using PSS/E simulation software. From studies conducted, it is clear that implementation of SVR system can bring great potential and benefits to TNB in-term of system loss reduction, better voltage profile, and control and effective utilization of reactive power resources.