ABB's high voltage hybrid switchgear for reliable power in Sofia city centre

The substation located in Hermes Park building in Sofia city supplies electrical power to the European Trade Center and to shops and office areas in the proximity of approx 250’000 sqms.

The substation is connected to 2x110 kV air transmission lines owned by the National Electric Company. ABB was responsible for the design, delivery of equipment, engineering, erection and final commissioning of the substation. ”The creative model used for the 110/20 kV ETC substation demonstrates once more ABB’s commitment to deliver energy efficient hi-tech solutions to its customers, leading to power savings and environmental protection.” - said Peter Simon, Country Manager of ABB in Bulgaria.

The substation was built with a single bus sectioned 110 kV side. For the connection to the existing 110 kV overhead lines are used two 110 kV cable lines, 980 m each.The 110 kV side of the substation is equipped with two PASS M0 modules (each with two breakers) – a hybrid ABB equipment with SF6 gas insulation. The 20kV side of the substations is equipped with ZS1 switchgear panels. The modern equipment used in the project was supplied from ABB factories in the Czech Republic, Sweden, Italy, Germany and Bulgaria. The project has been completed in a short time period of 14 months.

An outstanding advantage of this concept is that not only the space has been considerably reduced in comparison to a conventional outdoor substation, but also the reliability of the power supply has increased substantially. ABB’s control system allows remote operation of the substation and a smooth integration with the Building Management System of the Hermes Park. The specific features of the substations accomplished by ABB are the high reliability of the systems, easiness in operation, low maintenance costs as well as environmental benefits.