Adaptation of own consumption in the business building “Elektromreža Srbije” AD, Nacionalni dispečerski centar – (National Dispatch Center (NDC)) Phase II

The adaptation of own consumption in the National Dispatch Center (NDC) building, Phase II, was carried out from December 2017 to March 2020 at Vojvode Stepe 412, Belgrade, under investor “Elektromreža Srbije” AD Beograd. This project envisages the adaptation of the power supply system of the facility’s own consumption: replacement of the 10 kV switchyard in the 10/0.4 kV substation, no. V-1551 and replacement of two 10/0.4 kV transformers in TS 10/0.4 kV, no. V-1551, adaptation of 0.4 kV rail connections, adaptation of the existing monitoring system and adaptation of accompanying systems and installations.

To supply the necessary consumers, there are two diesel generators in the building as backup power sources, which are 100% spare for each other. The power of the diesel generator is 886 kVA/708 kW (“stand-by”) / 805 kVA/644 kW (“prime”).

The existing power supply and distribution system is used to connect and power the complete equipment for control informatics of NDC, TK system EMS AD and Data Center EMS AD, whose functionality must not be interrupted.

Existing 10 kV plant in SS 10/0.4 kV, no. V-1551 consists of 8 (eight) cells.

Existing home transformers T1 and T2 (dry) have a transmission ratio of 10±2×2.5% / 0.4 kV, power 1600 kVA, Dyn5 couplings and represent 100% reserve to each other. Transformers are prohibited from operating in parallel on the low voltage side.

At the site of the existing 10 kV switchyard, a new 10 kV switchyard was installed. The newly designed 10 kV switchyard (RP) consists of modular, metal-shielded, air-insulated, type-certified cells for indoor installation, rated voltage 12 kV, rated current 630 A, withstand one-second short-circuit thermal currents 25 kA.

At the place of the part of the existing, armored rail distribution (transformer-main distribution 0.4 kV), a new shielded, type-tested, prefabricated 0.4 kV bus distribution was installed.

A new remote station (RTU) was installed in the existing SS V-1551, which enabled complete supervision and management of a part of the newly installed 10 kV switchyard (K4, K5, K6 and K7), by EPS Distribucija – Pogon Beograd.

During the adaptation, the existing monitoring system of the complete facility was expanded. The SCADA system is designed so that, similarly to the old building, it shows the status of medium voltage switches, namely water cells, connecting cells and transformer cells.

After the works performed, the security of electricity supply to all vital consumers in the NDC building was increased, and thus the security of the electric power system of Serbia and the international exchange of electricity, which goes through our system.