Case studies
Challenge
The power plant, owned by the Ministry of Energy, consists of a steam unit and six gas turbines. As a result of military conflicts in past decades, some generating units were damaged or completely dismantled. Following the end of the conflicts, a gradual rehabilitation and modernization program was initiated, including the restoration of the high-voltage distribution systems.
IVEP participated in the project by delivering two key high-voltage solutions, each addressing a different technical challenge.
Indoor Medium-Voltage Switchgear for Secondary Distribution – Type MVSI-DS
Technical Parameters
- Rated voltage: 17 kV
- Rated current: 400 A
- Delivery date: July 29, 2021
Assignment and Challenges
The original MV feeder supplied an auxiliary transformer for low-voltage technologies within the so-called Power Island. Due to the high short-circuit power and significant asymmetry of short-circuit currents, it was not possible to use a standard catalog solution.
Additional challenges included:
- installation of the feeder inside an existing MV substation,
- the need to maintain compatibility with surrounding equipment,
- increased safety requirements in the event of a fault on the LV side.
IVEP Solution
IVEP designed and delivered a special MV feeder MVSI-DS, which:
- includes both upper and lower insulating disconnectors,
- allows safe replacement of fuses,
- features an upper disconnector rated for the full short-circuit current for a minimum duration of 1 s,
- has a lower disconnector coordinated with the transformer protection and equipped with an earthing switch,
- increases operator safety during faults or maintenance interventions.
The scope of supply also included two independent earthing switches with a dual-lever mechanism, integrated into the existing substation.
Result
- Replacement of a non-compliant feeder without impact on surrounding equipment
- Improved operational safety and reliability
- A solution tailored to extreme short-circuit conditions
Medium-Voltage Switchgear for Supplying an Auxiliary Transformer Unit – Type MVSO-CH
Technical Parameters
- Rated voltage: 17 kV
- Rated current: 1,600 A
- Delivery date: September 14, 2021
Assignment and Challenges
The second part of the project addressed the replacement of two MV changeover switchgear panels enabling the selection of power supply from two independent sources. The original equipment was obsolete and difficult to replace with currently available market components.
Customer Requirements
- retention of both automatic and manual changeover functions,
- addition of a motor-operated drive,
- installation of voltage transformers on both the incoming and outgoing sides,
- new auxiliary circuits for changeover control,
- dimensional constraints – the equipment had to fit into the existing installation space.
IVEP Solution
IVEP designed the MVSO-CH MV changeover switchgear, which:
- fully replaces the function of the original solution,
- enables safe changeover between two power sources without the risk of parallel connection,
- supports both automatic and manual operating modes,
- is equipped with the necessary measuring and signaling devices,
- can be installed in an outdoor version or within a protective enclosure.
The cabinet dimensions were optimized to comply with the limited installation space of the existing power plant.
Result
- Modernization of a key power supply node for auxiliary technologies
- Increased operational flexibility and automation
- Full compatibility with the existing power plant infrastructure
Přínos IVEP
Tato dvojice projektů demonstruje schopnost IVEP:
- navrhovat nestandardní VN řešení pro rekonstrukce starších elektráren,
- pracovat s extrémními zkratovými proudy,
- přizpůsobit zařízení omezenému prostoru a existující infrastruktuře,
- dodat řešení přesně podle provozních i bezpečnostních požadavků zákazníka.