Abstract: This chapter focuses on the electrical equipments that are required to protect devices to safeguard them during fault conditions. Switchgear, cables, transformers, overhead lines, and other electrical equipments require protection devices to safeguard them during fault conditions. In addition, the rapid clearance of faults prevents touch and step potentials on equipment from reaching levels that could endanger life. The function of protection is not to prevent the fault itself but to take immediate action upon fault recognition. Protection devices detect, locate, and initiate the removal of the faulted equipment from the power network in the minimum desirable time. It is necessary for all protection relays, except those directly associated with the fault clearance, to remain inoperative during transient phenomena, which may arise during faults, switching surges, or other disturbances to the network. Protection schemes are designed on the basis of safety, reliability, and selectivity. While the earliest relays were electromechanical in construction, technological developments led to the introduction of solid state or static relays using discrete devices, such as transistors, resistors, and capacitors. Advent of microprocessors led to the development of microprocessor-based relays and this culminated with today's state-of-the-art system of numerical relaying, where the measurement principles themselves changed from analog to numerical.
Publication Year: 2011
Publication Date: 2011-12-12
Language: en
Type: book-chapter
Indexed In: ['crossref']
Access and Citation
Cited By Count: 2
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot