The Golovnaya Hydropower Plant is a multipurpose power station located in the lower reach of the Vakhsh cascade. It was commissioned in 1964 with a power capacity of 240 MW. It is one of the largest hydropower plant in Tajikistan and as such, is a strategically important source of power for both Tajikistan and its neighboring countries. It has been generating an average of 840 GWh per annum since 2005-2012 but frequent emergency breakdowns have reduced this figure in recent years. To prevent further decline, urgent rehabilitation works had to be undertaken as soon as possible.

Since the initial construction of the Golovnaya Hydropower scheme, no substantial improvements or modernization had been made to maintain its original efficiency, reliability, and safety standards or reduce operation and maintenance costs apart from one generating unit, Unit which was rehabilitated in 2012. As a result of this lack of upkeep, the condition of the plant has significantly deteriorated, affecting most of its electro-mechanical and hydro-mechanical components and systems.

The full replacement of units 1,2,3,5 and 6 of the Golovnaya hydropower scheme

To counter this decline in efficiency, Tajikistan’s government proposed a rehabilitation project for Golovnaya hydropower including the full replacement of units 1, 2 and 5. With financial support from the Asian Development Bank (ADB), this project was implemented by the State energy company Barqi Tojik, and following completion is expected to bring about substantial improvements in power generation during winter deficit season. The capacity of the power plant will reach 252 MW with average annual generation expected to be 1,130 GWh in 2021 based on average hydrology of past two decades.

The rehabilitation of the plant includes the complete replacement of Kaplan units 1, 2 and 5, and Block3 and Block 2 Generator Step up transformers 10.5/110/220 kV 250 MVA. Unit 3 and Unit 6 were finally not refurbished but replaced, this included governor and excitation systems, and SF6 generator circuit breakers.  

The project also includes the installation of oil spill containment facilities to avoid an environmental disaster in case of emergency.

The scheme includes two switchyards for power evacuation: Air Insulated Switchgears 220/10/6 kV and 110/35/6 kV. Specific actions for high voltage equipment include the replacement of switchgear bay by bay to minimize the energy loss due to switchyards outages. A new 220 kV tower was installed in 220 kV switchyard to implement the new 220 kV transmission line from powerhouse to switchyard; additional 220 kV transformer bay will connect the new Block3 transformer to the switchyard.

All 220 kV and 110 kV lines from the powerhouse were refurbished, including towers and gantries. New control buildings were built to enable the management of separate entities between generation, transmission and distribution.

Both 220 kV and 110 kV substations were provided with specific and redundant protection systems, including Special Load Shedding System.

Rehabilitation, modernization and upgrade

The successful completion of rehabilitation works at Golovnaya ensure a stable source of hydro-power not just for Tajikistan but also its neighbors, it will help meet growing demand in the region. It also reduces emissions as compared to fossil fuel generation and is intended to help maintain balance between power supply and water resources availability. The project requires considerable investment from international stakeholders to ensure its rapid completion - an important step towards ensuring long-term sustainability of energy sources in the region.

It was also reported that Khatlon region supplied mainly by Golovnaya hydropower plan experienced many outages due to voltage drops and overloads; thus the rehabilitation of Vose 110/35/10 kV substation (close to completion) and new Rudaki 110/10 kV substation to increase the daily energy availability were realized.

Gruner’s services for the rehabilitation of the Golonaya hydropower scheme

In association with KGAL and Sofreco, Gruner provided owner’s engineer services for the following tasks:

• Preparation of the Switchyards Contract for tendering, including:

1. 1. Assessment of the condition of the 110/35/6 kV switchyard (“110 kV Switchyard”) and the 220 kV switchyard, and
   2. Preparation of concept designs for their rehabilitation.

• Assist the PMU with the competitive procurement of the Switchyards Contract, including:

1. 1. drafting a Request for Proposals;
   2. assisting the PMU in soliciting and evaluating bids, and
   3. negotiating with the preferred bidder leading to the award of a contract.

• Provision of project management and contract administration services during the construction period of both the Powerhouse Contract and the Switchyards Contract.
• Feasibility study, preliminary design, tender document, and procurement assistance.
• Construction supervision and commissioning of 220 kV Switchyard, including four line bays, three transformer bays, and two new Generator Step up Transformers 10.5/110/220 kV 250 MVA OFAF.
• Construction supervision and commissioning of the 110 kV double busbar switchyard with transfer bus, including eight-line bays, three transformer bays, one coupling bay, one transfer bus bay and two new Distribution Transformers 110/35/6 kV 25 MVA.
• Construction supervision and commissioning of 220 kV,110 kV and 35/6 kV control buildings, including review of protection system, and telecommunication design.
• Construction management of the Powerhouse EPC Contract, including commissioning tests and guarantee tests of five units.
• Detailed design and technical specifications of 110 kV rehabilitation works in Vose substation, including seven-line bays, two transformer bays, one coupling bay, one transfer bus bay and two new Distribution Transformers 110/35/10 kV 25 MVA, 35 kV and 10 kV control building.
• Detailed design and technical specifications of the new 110 kV Rudaki substation, including two transformer bays and two Distribution Transformers 110/10 kV 16 MVA, and 10 kV control building.
• Detailed design and technical specifications of new 110 kV transmission line between Vose and Rudaki substations

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