Semnan University Press Journal of Modeling and Simulation in Electrical and Electronics Engineering 2821-0786 5 2 2025 09 24 UHF Detection of Partial Discharge in High-Voltage Air Insulated Switchgear Using Improved Vivaldi Antenna 11 17 10105 10.22075/mseee.2025.35958.1189 EN Mohammad-Reza Nickpay Tehran Regional Electric Company, Tehran, Iran. Mohammad Danaie Faculty of Electrical and Computer Engineering, Semnan University, Semnan, Iran. Roohallah Amirabadi Tehran Regional Electric Company, Tehran, Iran. Vahid Yari Tehran Regional Electric Company, Tehran, Iran. Karim Goudarzikia Tehran Regional Electric Company, Tehran, Iran. Journal Article 2024 11 17 Partial discharge (PD) is a major concern in high-voltage electrical equipment, and its detection is crucial for ensuring the reliability and safety of power systems. In high voltage (HV) air-insulated switchgear (AIS), which is commonly used in the transmission and distribution of electrical power, PD can occur due to various factors such as insulation defects, voids, or impurities. Detecting PD at an early stage is essential to prevent equipment failure and costly downtime. Ultra-high frequency (UHF) detection methods are widely used for PD detection in HV AIS, as they offer high sensitivity and the capability to detect PD signals over long distances. In this paper, we will discuss using Vivaldi directional antennas for PD detection in HV AIS, focusing on their advantages, challenges, and potential applications. The simulation was carried out using CST Microwave Studio, and the result revealed that the antenna has a wide impedance bandwidth of 100% in the range of 0.5 to 1.5 GHz with S11 ˂ -10. An average gain of 5 dB and a maximum gain of 8.62 dB are achieved at the operational frequency band. https://mseee.semnan.ac.ir/article_10105_3f1d8be469dede6dd03fd8d1e17be288.pdf