Testing and measurement (T&M) solutions play a pivotal role in ensuring a safe, efficient and environmentally sustainable operation of power plants. These solutions are indispensable for extending the lifespan of plant assets, enabling early detection of potential failures and minimising unplanned equipment outages. The implementation of T&M solutions entails deploying a range of sophisticated sensors, transmitters and associated equipment strategically throughout the plant to monitor crucial parameters such as water quality, pressure, temperature, flow rates, emission levels and combustion efficiency.
The comprehensive monitoring facilitated by T&M solutions covers critical aspects such as combustion performance, water chemistry analysis and stack emissions management. By continuously monitoring these parameters, power plants can enhance their operational efficiency, reduce emissions and optimise both routine maintenance and emergency repairs. This proactive approach not only ensures the reliable performance of plant equipment but also contributes significantly to meeting environmental standards and regulatory compliance. Further, T&M solutions enable power plant operators to gather real-time data, which is essential for making informed decisions about operational adjustments and maintenance schedules. By leveraging advanced T&M technologies, such as digital monitoring systems and automated data analytics, utilities can achieve greater operational transparency and efficiency.
Thermal power plants
Emission and effluent monitoring
Power generation companies employ various advanced technologies for continuous monitoring of emissions and effluents online. These include continuous emission monitoring systems (CEMS), predictive emission monitoring systems (PEMS), continuous effluent quality monitoring systems (CEQMS) and continuous ambient air quality monitoring systems (CAAQMS). These systems enable real-time monitoring of air and water pollution.
CEMS specifically focuses on monitoring pollutants such as sulphur oxides, nitrogen oxides (NOx) and particulate matter emitted from stack emissions. CEQMS, in contrast, monitors parameters such as pH levels, total suspended solids and temperature of effluents discharged from power plants. These monitoring systems are mandated by the Central Pollution Control Board for stack emissions and effluent quality monitoring across various categories of highly polluting industries, including power generation. CAAQMS plays a crucial role in monitoring ambient air quality in real time, providing continuous data on air pollutants in the surrounding environment. Additionally, mercury analysers are employed to meet specific monitoring requirements for mercury emissions.
CEMS
CEMS employ a sophisticated technology to monitor emissions from power plants. These systems utilise complex extractive analysers that extract flue gas samples from ducts and analyse them using gas sensor modules or advanced spectroscopic techniques. For measurement accuracy, in-situ analysis is favoured, where sensors are directly placed in the flue gas stream or utilise line-of-sight optical absorption methods. CEMS operates by providing continuous, real-time data on pollutant levels, enabling power plant operators to take immediate corrective actions in response to any deviations from emission norms. Moreover, CEMS allow for remote access to plant performance data and facilitate ongoing checks on the effectiveness of air pollution control devices. However, utilities encounter several challenges when implementing CEMS. These include selecting suitable CEMS systems and suppliers that meet regulatory requirements, managing multiple data formats and platforms, and ensuring seamless integration with the existing plant infrastructure. Overcoming these challenges necessitates close coordination between central and state regulatory bodies to establish coherent standards and protocols for CEMS deployment and operation. Additionally, establishing robust audit mechanisms and compliance procedures is crucial to ensure the accuracy and reliability of emission data reported by CEMS.
PEMS
PEMS, a next-level emission monitoring technology, uses algorithms to predict emissions based on input parameters rather than hardware sensors. PEMS is often integrated into broader environmental monitoring approaches, addressing multiple plant sources. When combined with data acquisition and handling systems and integrated into plant-wide information technology and communications networks, PEMS serves as a diagnostic tool to lower emissions and enhance combustion efficiency.
Combustion monitoring
Efficient combustion is crucial for ensuring cost-effective power generation and reducing emissions from power plants. Balancing the amount of air supplied to the furnace is critical – while sufficient air is necessary for complete coal combustion, excessive air can increase NOx formation and reduce the overall plant efficiency due to higher fan power consumption and heat losses. Achieving the optimal air-fuel ratio is challenging but essential. Monitoring flue gas oxygen levels is key to adjusting combustion for maximum efficiency. Combustion gas oxygen analysers accurately measure oxygen content, enabling precise control of air supply to the burner. Flow meters and actuators further assist in maintaining the ideal fuel-to-air ratio and operating parameters. Enhancing sensor accuracy and employing advanced control systems ensure optimal boiler performance and settings under varying conditions. Additionally, monitoring sodium levels in the boiler with sensitive online monitors is crucial for managing dissolved compounds effectively.
Feedwater monitoring
Monitoring and controlling the quality of water and steam in the feedwater is crucial for optimal performance of a coal-fired power plant. Various chemicals must be managed carefully to ensure efficient steam generation. Dissolved oxygen in the feedwater can lead to boiler pitting and reduce its lifespan. Adding hydrazine to the feedwater helps mitigate oxygen by converting it to nitrogen and water. However, at high temperatures and pressures, ammonia can form, increasing feedwater pH levels and the risk of corrosion. Silica, another concern, can impair heat transfer and potentially cause turbine issues due to blade precipitation. Monitoring pH levels helps assess contamination levels and determine appropriate treatment measures
Renewable power plants
As renewable energy capacity continues to expand, there will be a rising demand for T&M of renewable energy equipment such as solar cells, solar photovoltaic (PV) modules, wind turbine generators and hydropower plants.
Solar plants
Solar PV plants can be monitored either manually or remotely, depending on their scale and location. Remote monitoring is generally favoured for its reliability, improved operations and maintenance efficiency and enhanced performance of the PV system. This method employs sensors, signal processing units, data transmission systems, data storage and cloud-integrated analytics. These components enable thorough condition monitoring and structural assessment of solar plants, enabling proactive maintenance to address component failures before they disrupt energy production.
Wind plants
Condition monitoring of wind turbines is crucial, especially for structural components such as foundations, blades and towers, as their failure can significantly impact operational costs. Offshore wind turbines face heightened exposure to harsh environments, increasing their vulnerability. Therefore, monitoring these structural elements is essential to reduce maintenance expenses and prevent severe failures. Additionally, monitoring the overall turbine condition helps detect changes in behaviour and predict faults, thereby minimising performance decline and expenses. Key sensors used for wind turbine condition monitoring include accelerometers, temperature sensors, pressure sensors, rotational speed sensors and current clamps.
Hydro plants
In June 2023, the Central Electricity Authority introduced guidelines for conducting field efficiency tests in hydroelectric power plants, including those with pumped storage capabilities. These guidelines apply universally to units of all sizes and types, covering generators, motors, impulse/reaction turbines, and pump-turbines exceeding 5 MW in capacity. They mandate efficiency tests for synchronous generators/induction machines to validate their performance on-site, alongside tests to measure the efficiency of turbines and pumps. The testing process utilises essential instruments such as flowmeters for fluid flow rate measurement, thermal detectors for monitoring liquid coolant temperatures and calorimeters for assessing cooling systems such as bearing oil and water in air- or gas-cooled set-ups. Furthermore, instruments such as micro-ohm meters for precise resistance measurement, digital power analysers, three-phase digital watt meters and multifunction meters are employed for accurate measurement of electrical parameters.
Conclusion
With the emergence of new age technologies, T&M of generation equipment is evolving rapidly. Drones are increasingly being used to monitor power plants remotely, offering benefits such as evaluating plant condition, accessing inaccessible areas, reducing downtime and maintenance costs, and enhancing personnel safety. They are particularly valuable for monitoring power stations equipped with flue gas desulphurisation systems and assessing internal chimney linings during outages to prevent corrosion and structural damage.
Additionally, power gencos are adopting advanced control solutions for monitoring and managing equipment parameters through automation. Machine learning algorithms are gaining popularity for intelligent fault detection, predictive maintenance and comprehensive system monitoring. Further, the T&M sector is poised for growth driven by advancements in recognition technology, artificial intelligence, machine learning and IoT-enabled instruments. This evolution is crucial as the demand for T&M services in renewable energy equipment, such as solar cells, PV modules and wind turbines, is expected to rise sharply due to the government’s ambitious target of achieving 500 GW of renewable energy capacity by 2030.