Ensuring the Correct Operation of Distance Relays Under Dynamic System Conditions

Distance relays are the most commonly used protection devices in transmission systems around the world. The recent large disturbances in North America and Europe demonstrated their sensitivity and impact on wide area disturbances. Modern distance protection relays are complex multifunctional devices that can perform much better under dynamic system conditions. Methods for improvement in their performance, as well as for testing their functionality are discussed in the paper.