ENERGO-PRO Networks carries out a re-inspection of the installed substations in North-East Bulgaria

ENERGO-PRO Grids completes the annual inspections and inspections of the facilities on schedule to prepare them for operation in winter conditions, when the load is greater. However, the company commissioned a re-inspection of the embedded substations on the territory of North-East Bulgaria in order to re-insure itself after the incident with the exploded substation in the city of Burgas.

The total number of substations owned by Energo-Pro Mrezhi is 11,391, of which 626 are built into residential and public buildings. Most of them were built at the time when the electricity distribution companies were state-owned, and in recent years the company builds such facilities only exceptionally, because everything is more complicated with them - both construction and maintenance. Compared to ordinary overhead substations, the construction and maintenance costs of embedded facilities are about twice as high.

Built-in substations are built in accordance with the existing general development plans of settlements and the opportunities they provide — mainly in the central parts of large cities, where the construction over the years has led to a lack of free plots for the construction of electrical facilities. Usually, the initiative for the construction of this type of substation is on the part of investors who do not want to allocate part of the expensive plots for a power facility.

The condition of the built-in transformer substations is monitored and maintained within the normative limits of the normal operation mode. Energo-Pro Grids maintains its substations in accordance with the current regulations, carrying out technical inspections and maintenance, scheduled repairs and upgrades of the facilities within the regulated deadlines.

In the case of built-in substations, there are increased regulatory requirements for fire safety, noise and vibration, which Energo-Pro strictly complies with. However, for purely technical reasons, their work sometimes causes complaints from those living in such buildings. The problem is that for fire safety reasons, dry transformers are installed in the built-in substations, which are noisier and with greater vibration during operation. For this reason, the company avoids building embedded substations and allows it only at the insistence of the investor and after coordination with local institutions.

In order to remove a given built-in substation, the residential building must be fed from another existing substation or a new one built. Usually, existing facilities in the central parts of cities are optimally loaded and could not take on additional load, which means building new facilities. And the construction of free-standing substations and technical infrastructure requires the presence of free plots in the existing general development plans of settlements.