Node station “Provadia” — renovated and modernized with the latest generation equipment

ENERGO-PRO invests BGN 170,000 in the complete rehabilitation of the key facility

ENERGO-PRO carried out a large-scale repair of the node station “Provadia” worth BGN 170,000. Thanks to the rehabilitation carried out, more than 7,000 customers of the company from the city of Provadia and the surrounding area will receive significantly more secure electricity supply.

Node station “Provadia” is located in the area of the old cemetery park of the city of Provadia. It was built about 40 years ago and, like any depreciated facility, its operation has become increasingly inefficient over the years.

Within a few months, ENERGO-PRO Networks specialists carried out the replacement of the “heart” of the station - the primary and secondary electrical equipment and switchings. Part of the medium voltage disconnectors, voltage and current transformers were replaced, new electrical panels were also installed. “The materials and elements used are of the latest generation of technological development, purchased by the best — but not the most expensive — manufacturers of such facilities,” says Mr. Simeon Evtimov, Director at ENERGO-PRO Networks, head of rehabilitation. Morally and technically obsolete oil circuit breakers (produced in 1967!) were replaced with vacuum ones, the main advantage of which is their reliability in operation and their longer service life. In addition to their better technical parameters, they are more environmentally friendly.

Another important part of the rehabilitation was the replacement of the electromechanical relay protections of the node station with digital ones. Reliability of facilities in the power system determines the quality of power supply. No matter how high-quality the individual equipment is, no matter how accurately it is installed and maintained, emergency situations are not completely excluded. For this reason, the protection mechanisms installed in the stations are essential. Well-chosen and tuned relay protection reduces the time during which customer power can be cut off and limits damage to the equipment itself in the event of an accident.

Undoubtedly of great importance in the overall rehabilitation of the Air Force “Provadia” is the telecechanics for remote control built and put into operation. This system reduces the response time in case of accidents, as the facility is controlled directly by the Central Network Management (TMC) Varna. Thus, by controlling the node station from a distance, the possibility of rapid response and elimination of faults and accidents occurring on the power distribution network in the area is significantly improved. Remote control of the node station represents a significant advantage both for the operation of the electricity distribution company and for all its customers, since it provides the possibility of 24-hour monitoring of facilities, more secure and reliable control of the network, as well as making switches without disturbing the normal and uninterrupted supply of electricity consumers.

“In order to supply electricity with the necessary technical parameters to the final customers, our company constantly makes efforts to invest in the maintenance of the facilities in good technical condition, as well as to develop the network through the construction of new facilities. ENERGO-PRO Networks serves 98 node stations located on the territory of North-East Bulgaria. Given the fundamental importance of node stations as part of the network, in recent years a number of facilities of this kind have been completely or partially retrofitted. The rehabilitation of Air Force “Provadia” is just one of the measures we have taken to improve the quality and security of power supply for our customers in the area of the town of Provadia”, said Mr. Martin Mirchev, member of the Management Board of ENERGO-PRO Networks.

With the obsolescence of a facility such as a hub station, the risk of accidents and power deprivation for a large number of electricity consumers increases significantly. In this regard, despite the unfavorable regulatory framework in which it has been placed in recent years, the electricity distribution company continues to invest in improving the condition of facilities such as the Provadia Air Force, which are key to improving the electricity infrastructure. The rehabilitation project of the facility was completed at the end of 2013.

Curious:

Why are node stations key to the operation of electrical networks?

A node station is a facility, part of the electricity distribution network, which generally has the function of distributing electrical energy. As is known, the electricity that reaches our homes must have a nominal voltage of 230V (according to the BDS it is permissible for it to vary +/- 10% of this value). In production in different types of power plants, however, electrical energy is generated with a voltage of 110 kV, or the more common term — high voltage. In order to be able to be transferred to the distribution network, it must be transformed to a lower voltage — 20 kV, or the so-called medium voltage. After this transformation, the energy is transferred along the company-owned power lines and “enters” the substations, where it undergoes a transformation again to “exit” with a voltage of about 230 V — a low voltage. The main purpose of the node station is to distribute electricity by reaching one or more medium voltage power lines and a larger number of medium voltage power lines coming out, which supply a large number of substations. The distribution of energy in the node stations ensures the “power reserve”, which is important for all customers, i.e. at least one additional power line is always available at the output of the node station, which can be used as an alternative when one of the other power lines is switched off. In other words, when carrying out planned shutdowns (due to repair work) or unplanned power outages (in case of accidents) through the node station, the so important continuity of the power supply is ensured. Even if a short interruption is required, it is so that customers can be powered on another power line that is at the outlet of the respective node station while working on the failed or repaired power line. This minimizes the time during which homes and industrial sites remain without power, regardless of the reason for it. The distribution of electricity in the node station gives another advantage, and that is that in the event of a repair or an emergency situation, a much smaller number of customers can be left without power supply precisely because the energy supplied to the node station is distributed to several outlets.

Many of these facilities also have an important connecting function between individual substations. The functions of the node stations determine their key role in the smooth operation of the power distribution network.