Gurevich V. Power supply devices and systems of relay protection

Monograph, the 1st edition, CRC Press, Boca Raton (USA), 2014, pg. 248Development of modern machinery and transition to microprocessor-based elements is accompanied by constant sophistication. Modern digital protection relay (DPR) devices, unlike old electromechanical relays, require power supplies. Quality and reliability of relay protection (RP) power supply systems and devices affect RP’s ability to perform its functions. The power supply of RP starts at a transformer for a substation’s own needs and ends at a built-in power supply of the DPR, including a system of auxiliary current, battery chargers, accumulator batteries, uninterruptable power supply (UPS), auxiliary systems of monitoring of insulation, and integrity of auxiliary current circuits.
All these systems and devices are connected by many links and represent an integral organism, where a failure of one organ can result in a serious “illness” of the whole organism. For example, routine work to find a location of insulation breakage in a 220 V DC system by means of a standard device, which has been done multiple times and with which all electricians are so familiar, can suddenly result in the switching off of a power transformer and a full range of overhead transmission lines at 160 kV, redistribution of the load to other lines, their overload, and, finally, the breakdown of the whole energy system.
The book is meant for engineers and technicians who use AC and DC auxiliary power systems of power plants and substations, as well as relay protection systems. The book may be useful for teachers and students of corresponding disciplines at vocational schools and higher education institutions.Basic components
Secondary power supplies
Battery chargers
Uninterruptable power supply
Lead–acid accumulator batteries
Systems for supervision of substation battery continuity
Backup of substation DC auxiliary power systems
Insulation problems in substation DC Auxiliary power supply
Voltage disturbances in auxiliary power supply