Assessing the Financial Impact and Mitigation Methods for Voltage Sag in Power Grid

Voltage sags, as defined by the IEEE Standard, refer to sudden drops in voltage magnitude that last for a duration greater than 0.5 cycles of the power frequency but less than or equal to 1 minute. These events are considered significant in power quality issues. The change rate of voltage during a voltage sag can range from 0.1 to 0.9 per unit (p.u.) of nominal voltage, where 1 p.u. represents the nominal voltage level. Addressing the power quality (PQ) challenge is a critical component of ensuring the reliable and efficient operation of modern power systems. Advances in PQ monitoring and control technologies, power electronic devices, smart grid technologies, and PQ standards have all contributed significantly to improving PQ and enhancing the resilience and responsiveness of power systems. However, voltage sags are particularly challenging to resolve and may require a range of solutions. Voltage sags are a critical factor in PQ and can cause significant disruptions in the power system. As a result, mitigating voltage sags is a key area of focus in PQ improvement efforts. This paper presents an in-depth analysis of voltage sags in power grid, including their causes, characteristics, and harmful effects on electrical equipment and industrial processes. The authors highlight the significance of voltage sag mitigation techniques to reduce the economic losses and damage caused by these PQ issues. The paper provides an overview of existing mitigation techniques, including dynamic voltage restorer (DVR), distribution static synchronous compensator (D-STATCOM), and other custom solutions. Additionally, the paper discusses the economic impact of voltage sag on various industrial sectors, including the semiconductor and information industries. The authors emphasize the need for continued research and development of effective voltage sag mitigation techniques to enhance the stability and reliability of power grid and electrical systems. This paper is a valuable resource for researchers, engineers, and professionals in the field of power systems, providing insights into the causes and mitigation of voltage sags in the power grid.