This document provides an overview of HVDC (high voltage direct current) transmission. It discusses how HVDC transmission plays a major role in power transmission due to increasing energy demands. HVDC allows transmission over long distances with lower losses compared to AC transmission and requires only two conductors. The key components of an HVDC system include converters, smoothing reactors, harmonic filters, and electrodes. HVDC transmission configurations can be monopolar, bipolar, or homopolar, and applications include back-to-back, overhead line, underground cable, and submarine transmission. India's first long-distance HVDC projects were Rihand-Delhi and Chandrapur-Padghe.