Jelena Nikolić

As part of the TPP Kostolac A, since the first synchronization of its unit A1 in 1967, coal delivery has been operating, the task of which is to receive, store and delivery coal for the operation of TPP. With the construction of unit A2 in 1980, there was an increased consumption of coal, as well as a demand for more stable and reliable operation of the units, which led to the construction of a 6.3 kV switchgear in 2002. After exploitation and continuous operation, in 2023, the reconstruction and modernization of the 6.3 kV switchgear was carried out. There were no more spare parts for the equipment that was in operation, and a large number of manipulations led to more frequent electrical equipment failure. At the time of the reconstruction, most of the equipment in the switchgear was more than 21 years old. Maintenance and exploitation were based on the experience of the staff. Old vacuum circuit breakers with damaged contacts and worn-out motor-spring drives have been replaced by new vacuum power block circuit breakers that have a shorter operating time, higher tripping current and less need for maintenance. Microprocessor protections of the older generation have been replaced by protections of the latest generation that are more reliable, faster, more transparent, more efficient, more suitable for subsequent analysis of archived data and with more functions. Two spare fully equipped cubicles have been installed, which increased reliability and left a reserve for the needs of the technological process. A control system was installed and integrated into the existing SCADA system on the electrical control panel and full remote control of the switcgear was introduced. The reconstruction of the coal delivery facility resulted in simpler manipulation, easier maintenance, remote monitoring and control, and most importantly, the level of reliability of the powered equipment has been raised.

Keywords: coal delivery, microprocessor protection, 6.3 kV switchgear, SCADA system, vacuum circuit breaker