Evaluation of Thac Mo Hydropower Plant Units after Over 29 Years of Operation

Thac Mo Hydropower Plant is located on the Be river in Binh Phuoc province, in three districts (Phuoc Long, Bu Dang, Bu Gia Map), Southwest direction approximately 170 km from Ho Chi Minh City, this is the top step of the total energy exploitation diagram of the Be river basin.

This construction began at the end of 1991. It is classified as a level II project. By 1995, it was put into operation with two units, having a total installed capacity of 150 MW, supplying electricity to the Southern power system in the period 1995 – 2000 and now it has been integrated into the National Power System with annual electricity output is 610 million kWh. In addition, the regulatory regime of Thac Mo Hydropower Plant will supply a water source for irrigation and daily life in the downstream area of Be River – Phuoc Hoa – Ho Chi Minh City, with a dry season flow of 56m3/s.

Overview of generating units H1 and H2

Nowadays, the generation units of Thac Mo Hydropower Plant have been operating for nearly 30 years. The phenomenon of mechanical aging of materials (especially insulating materials) is becoming increasingly evident with high frequency. Moreover, the existing electrical equipment of the two units, produced during the Soviet era, poses significant challenges in finding replacement parts due to geopolitical tensions. Additionally, the long-term operation process has led to multiple points of insulation damage in the stator windings of the generator due to Partial Discharge (PD) phenomena.

Om May 31, 2023, the National Power System Dispatch Center (A0), now is National Power System and Market Operator Company Limited (NSMO)– issued document No. 1880/ĐĐQG-TTĐ regarding the operation of hydro power plants when the reservoir water level (RWL) is low. According to this document, the load demand has increased significantly since April 2023, while the water inflow to hydro power reservoirs nationwide has been unfavorable. As a result, all types of power sources have been maximally mobilized, including oil-fired thermal power units. In the near future, as the load demand continues to rise during the peak hot season, A0 has requested power generation companies to study solutions to operate the units with reservoir water levels below the dead water level to ensure safe and reliable power supply for the national grid.

Given these issues, optimizing the plant’s operational capacity and water levels is essential to avoid affecting production and operation. Therefore, in order to ensure safe and stable operation, it is necessary to conduct surveys, evaluations, and propose repair and upgrade solutions for Thac Mo Hydropower Plant.

Power Engineering Consulting Joint Stock Company 3 (PECC3) is the consultant for the investor, collaborating with domestic and international technical experts. The role of PECC3 in the project is conducting surveys and preparing evaluation reports for generating unit H2 (in 2023) and unit H1 (in 2024), specifically as follows:

– Collecting data (equipment history, design/manufacturing/operation documents, etc.) – Conducting on-site technical surveys, including visual inspection of equipment (generators, transformers, hydraulic turbines) and supervising relevant tests on generators and transformers. – Discussing about assessment results with foreign experts (generators, turbines), domestic experts (transformers) and experience in maintenance, replacement form other Hydropower plants to propose optimal solutions for the investor. – Preparing evaluation reports on the current state of the equipment, advising on solutions (repair/replacement/capacity upgrade), and estimating costs for each solution.

The evaluation reports conducted by PECC3 provide the investor with a comprehensive view of the technical condition of the plant’s operational equipment. This enables the investor to choose optimal solutions that are financially suitable, ensuring efficient, safe, and stable operation in the future.