With the growing integration of renewable energy into the grid, hydropower is expected to play a major role in addressing the intermittency and balancing requirements. Hydropower projects are capital intensive. If these assets are maintained well, significant benefits can be extracted from the plant over a longer period of time as compared to other sources of energy. Therefore, the technical needs of hydropower plants are focused primarily on addressing the various challenges the industry faces. Moreover, there is a growing trend towards digitalisation in the power industry given the benefits it offers, including reduced operations and maintenance (O&M) costs, improved data analysis and enhanced project management.
Depending on the grid frequency, hydropower plants are required to ramp up or down generation, inject reactive power based on the local bus voltage, and provide quick start and stop capabilities to support the grid in peak times. Digitalisation helps hydropower plants to fulfil these requirements more efficiently and increases equipment life as well. It may also help address the plants’ operational issues and lags in maintenance. Although digitalisation has been prevalent in other parts of the world and industries for some time, its adoption in India has gained traction only recently. Digitalisation aims to enhance the efficiency of hydropower plants to reduce costs, increase flexibility and improve the management of assets.
A look at the key aspects of digitalisation and its benefits for the hydropower segment in India…
Key drivers
Digitalisation has a number of benefits for the hydropower segment. It delivers better connectivity, ensures accurate asset management, enables predictive maintenance, and facilitates efficient operations through data and analytics. It improves planning and project design, making them more efficient and less expensive. It also lowers O&M costs by enabling predictive maintenance, reduces water usage, improves system reliability and stability, decreases the number of unplanned outages and downtime by easily detecting the point of failure, and extends the asset lifetime. Longer lifetimes yield higher revenues and reduce the requirement for capex. Further, improved connectivity and monitoring build a strong case for remote operations. Digitalisation also helps in the integration of hydropower operations with other variable renewable energy sources. The operations of hydropower plants can be closely coordinated through the use of digital systems so that hydropower fills the supply and demand gaps in solar generation, and hydropower generation can be ramped down when solar power is available in order to conserve water. Digitalisation also optimises reservoir management and extends the operating range of existing hydro units.
New technologies
Digital components are available at various stages of hydro plant operations, right from the design and construction of the plant to its operation, management and maintenance. Some of the key aspects of a digitalised hydropower plant are distributed control systems (DCS), digital governors and excitation controllers, numerical relays, and internet-based condition monitoring and predictive maintenance systems.
DCS involves a network of instrumentation comprising sensors, flow switches, transducers, etc. It provides real-time information to operators, allowing complete control of machines and auxiliaries from the control room (often located at a remote location). With a DCS, no manual intervention is required. Numerical relays can record and store a large number of events and disturbance records, providing excellent fault diagnosis tools. They are highly configurable as the setting parameters and operational logic can be changed easily. The latest numerical relays, which are based on open protocols, can communicate on the plant control network, improving ease of access.
The internet of things brings together industrial machines, advanced analytics and people. It is a network of a multitude of connected devices that monitor, collect, exchange, analyse and deliver valuable new insights. An internet-enabled condition monitoring system analyses remotely collected real-time operational data of multiple power stations. It uses machine learning processes to track the health of the plant, detect failures in advance, and improve the diagnostics and prognostics of faults. Intelligent predictive maintenance systems are algorithms and models designed to analyse data from the power plant control system. They notify the changes in function and performance using equipment sensors, and identify faults before any serious malfunction occurs. Some power plants across the world have also installed drones for the monitoring and maintenance of hydroelectric plants.
The digitalisation of hydropower plants, control systems and the surrounding networks is an emerging industry trend that promises to optimise performance and asset management. With the growing requirement for ancillary services and the introduction of regulatory frameworks, more analytical tools are needed to optimise operational performance. Digital systems such as SCADA, digital governors and excitation systems have helped in better implementation of grid requirements.
Another solution is the computational fluid dynamics (CFD) tool. CFD is an efficient and inexpensive tool to make internal flow predictions for good accuracy. It detect any sort of flow problems to be and makes improvements in the geometry of turbine components. It is used for checking the efficacy of alternative turbine designs for optimisation before the final experimental testing of selected designs. Another emerging trend is allowing for flexibility in turbine design. Today, turbines are available in varying configurations, such as horizontal and vertical, to ensure the efficiency and reliability of operation under extreme conditions. This enables longevity, durability, reliability and robustness, and allows a wide range of operations.
Another development in the O&M space is the use of a thermal spray coating process for extending equipment life. This step significantly increases erosion resistance and enhances corrosion protection. High velocity oxygen fuel (HVOF) coating of underwater parts such as runners, guide vanes and cheek plates can be done at silt-affected power stations for mitigating abrasion/erosion problems. The high velocity air fuel (HVAF) coating process, which is similar to HVOF, uses compressed air in place of oxygen fuel. While HVAF is currently at the testing stage in India, it has various advantages over HVOF, such as no oxygen usage, leading to lower costs, better adhesion, hardness and toughness.
Predictive maintenance of hydropower systems is another solution that can yield immediate savings in maintenance costs. Some of the diagnostics for condition monitoring, which is a major component of predictive maintenance, being implemented in the industry include air gap monitoring, stator frame and rotor vibration, generator temperature, thrust and guide bearing temperatures, and ultrasonic flow measurements.
Challenges and the way forward
Despite the many benefits, there are some obstacles in the digitalisation of hydropower plants. Poor network connectivity between power stations and remote centres poses a major challenge as effective digitalisation depends on strong communications connectivity. For commercial confidentiality reasons, asset owners and operators may not be willing to share information about individual power plants and network infrastructure. This issue can be addressed by building a robust communication network. There is also the risk of cyberthreats, which increases with digitalisation. To minimise these threats, utilities need to raise awareness about cybersecurity and build strong strategies for technological and cyber resilience. Another challenge in the implementation of digitalisation initiatives is the lack of financial incentives and IT infrastructure with gencos. The industry has raised concerns about the lack of incentivising investments in digital technologies. Moreover, asset owners and operators are often not willing to share data and information about individual power plants and network infrastructure among peer groups and companies in order to preserve commercial confidentiality.
These challenges need to be overcome and hydropower stations encouraged to adopt emerging technologies and innovative approaches in order to improve their operational performance and cope with cybersecurity risks. Moving forward, what is needed is the creation of greater awareness about the benefits of digitalisation, a comprehensive policy for developing the cyber insurance market, and the incorporation of the latest technologies to enhance the operational efficiency of hydro plants.