ENERGO-PRO Grids completely renovated the equipment of the hub station “Karlovtsi”
The facility is of strategic importance for improving the security of electricity supply to customers in the area of the “Republic Pass”
In the past year, ENERGO-PRO Networks continued to invest funds in renovation and modernization of equipment in substations and node stations on the territory of North-East Bulgaria, despite the financial possibilities limited by the regulatory framework.
The company carried out a complete rehabilitation of the “Karlovtsi” interchange station, located at the southeastern edge of the village of Karlovtsi, near the “Passage of the Republic”. The facility supplies electricity to a hard-to-reach mountainous area, which is characterized by many shutdowns due to bad weather conditions, especially during the winter period. The node station was built in the 60s of the twentieth century, and after more than half a century of operation, despite its long service life, its efficiency has dropped sharply.
The reconstruction is worth over BGN 80,000 and is of key importance for customers in the area, as it reduces the response time in case of accidents, due to the fact that the manipulations are already carried out centrally and there is no need for an emergency team to reach the facility. In addition, the rehabilitation has led to an increase in the quality and security of power supply for the nearly 3500 customers, mainly domestic, customers. The facility feeds small settlements, most of which have a small number of inhabitants and are located in remote, hard-to-reach places. In this area there is also the village of Voneshta voda, known for the healing properties of mineral springs and the development of balneological tourism.
The node station has mainly a distribution function, that is, it distributes the electrical energy that reaches it through medium-voltage overhead power lines (HEVs). In this case, the power lines that reach the Gallevtsi plant are three: VEL Belitsa, VEL Sredni Kolibi and VEL Rajkovtsi. It is indisputable that in such mountainous areas, servicing facilities and locating accidents on overhead power lines requires a lot of effort on the part of the teams on duty. “Fixing damage in this rugged terrain, especially in severe winter conditions, sometimes takes hours, which inevitably affects the comfort of our customers. At the same time, the area offers conditions for the development of rural and balneological tourism, and in this regard, good infrastructure and reliable electricity supply are of particular importance. With the renovation of the node station, we were able to reduce the time to locate and eliminate accidents to a minimum, and this was felt by our customers during the current winter season. We will continue to gradually replace the most vulnerable sections of our network in order to guarantee the necessary quality and security of power supply to our customers,” said Mr. Petar Zhivkov, Head of Department “Service of Substations and Node Stations West” at ENERGO-PRO Networks.
The overhaul of the node station was completed last year and included the replacement of primary and secondary electrical equipment and switchgears. In the course of the reconstruction, the old medium-voltage oil circuit breakers were replaced with new vacuum ones, which have a higher operating rate and, last but not least, have a lower environmental impact. The old electromechanical relay protections were also updated with new digital ones, which protect the equipment from possible breakdowns in the event of accidents and reduce the time of power outages. During the repair, current and voltage transformers are installed in the node station, as well as a transformer for own needs. After the reconstruction, the facility now also has a rechargeable battery equipped with a rectifier. The rechargeable battery actually represents the “heart” of the node station. It ensures the independence of the operational power supply of the facility, which in practice means that if, as a result of an accident, the electricity supply to the node station stops, the rechargeable battery at the site allows a remote connection to the dispatch center, from where very fast and practically imperceptible to customers switches are made that restore their power supply.
Telemechanics in the hub station “Gyłvtsi” has also been completely renovated, which allows remote control of the facilities. The telemechanical control system is extremely important, as it gives the dispatcher complete information about the parameters and status of the network in real time. In this way, the localization and, accordingly, the elimination of accidents is carried out faster, since the emergency teams do not waste time to reach the facility. The object is equipped with a security system for protection in case of encroachments.
“The project for the renovation and modernization of the equipment of the Khelvtsi Node Station is of key importance for the development of the network in this high-mountain difficult area in Stara Planina. In addition to providing better quality power to customers in nearby villages, the node station has an important distribution function, i.e. in case of disconnection of one of the three power lines, the other two power lines at the outlet of the node station remain available, which can be used as an alternative. Jellovtsi Air Station also provides a connection between the substations “Dluga Laka” and “Elena”, which in total supply more than 20,000 customers. In many cases of planned repairs and accidents that occurred at some of the terminals of one or the other substation, the connection to the HSC “Karlovtsi” allows to supply backup power to the affected customers and thus prevent the inconvenience for customers due to the lack of power supply. “, shared Mr. Martin Stanev, Head of Department “Technology and Subconstruction” stations” in ENERGO-PRO Networks and project manager for reconstruction of the node station.
