• Energy Research

Accurate temperature estimation inside an electrical motor is key for condition monitoring, fault detection, and enhanced end-of-life duration. Additionally, thermal information can benefit motor control to improve operational performance. Lumped-parameter thermal networks (LPTNs) for electrical machines are both flexible and cost-effective in computation time, which makes them attractive for use in real-time condition monitoring and integration in motor control. However, the accuracy of these thermal networks heavily depends on the accuracy of its system parameters, some of which are difficult to calculate analytically or even empirically and need to be determined experimentally. In this paper, a methodology for the thermal condition monitoring of long-duration transient and steady-state temperatures in an induction motor is presented. To achieve this goal, a computationally efficient second-order LPTN for a 5.5 kW squirrel-cage induction motor is proposed to apprehend the dominant heat paths. A fully thermally instrumented induction motor has been prepared to collect spatial and temporal temperature information. Using the experimental stator and rotor temperature data collected at different motor operating speeds and torques, the key thermal parameter values in the LPTN are identified by means of an inverse methodology that aligns the simulated temperatures of the stator windings and rotor with the corresponding measured temperatures. Validation results show that the absolute average thermal modelling error does not exceed 1.45 °C with maximum absolute error of 2.10 °C when the motor operates at fixed speed and torque. During intermittent motor-loading operation, a mean (maximum) stator temperature error of 0.38 °C (0.92 °C) was achieved and mean (maximum) rotor errors of 2.11 °C (3.40 °C). These results show the validity of the proposed thermal model but also its ability to predict in real time the temperature variations in stator and rotor for condition monitoring and motor control.

Accurate temperature estimation inside an electrical motor is key for condition monitoring, fault detection, and enhanced end-of-life duration. Additionally, thermal information can benefit motor control to improve operational performance. Lumped-parameter thermal networks (LPTNs) for electrical machines are both flexible and cost-effective in computation time, which makes them attractive for use in real-time condition monitoring and integration in motor control. However, the accuracy of these thermal networks heavily depends on the accuracy of its system parameters, some of which are difficult to calculate analytically or even empirically and need to be determined experimentally. In this paper, a methodology for the thermal condition monitoring of long-duration transient and steady-state temperatures in an induction motor is presented. To achieve this goal, a computationally efficient second-order LPTN for a 5.5 kW squirrel-cage induction motor is proposed to apprehend the dominant heat paths. A fully thermally instrumented induction motor has been prepared to collect spatial and temporal temperature information. Using the experimental stator and rotor temperature data collected at different motor operating speeds and torques, the key thermal parameter values in the LPTN are identified by means of an inverse methodology that aligns the simulated temperatures of the stator windings and rotor with the corresponding measured temperatures. Validation results show that the absolute average thermal modelling error does not exceed 1.45 °C with maximum absolute error of 2.10 °C when the motor operates at fixed speed and torque. During intermittent motor-loading operation, a mean (maximum) stator temperature error of 0.38 °C (0.92 °C) was achieved and mean (maximum) rotor errors of 2.11 °C (3.40 °C). These results show the validity of the proposed thermal model but also its ability to predict in real time the temperature variations in stator and rotor for condition monitoring and motor control.

Following the urgency of climate change issues, investments in renewable energy sources and electrification of the transportation sector have enormously increased to facilitate the transition to a more sustainable future. However, as renewable resources like wind parks are replacing conventional power plants, new balancing solutions are required to strengthen grid stability. As responsive loads with quick dynamics, electrolysers operating in HRSs can present flexible balancing services to the power grid. To gain this benefit, this work examines the techno-economic features of providing different frequency grid services by an HRS, considering the possibility of hydrogen injection into the industrial and natural gas pipelines. The ratings of the subcomponents and dispatch plans are optimised to enhance the performance of the plant. A probabilistic mixed-integer linear programming problem is solved over one year with a time resolution of one hour and using real-world historical data based on the European electricity market. The simulation results indicate that the economic profits can be increased significantly as a result of participating in the ancillary service markets and meeting its operation specifications while the stable performance of the HRS is guaranteed.

Following the urgency of climate change issues, investments in renewable energy sources and electrification of the transportation sector have enormously increased to facilitate the transition to a more sustainable future. However, as renewable resources like wind parks are replacing conventional power plants, new balancing solutions are required to strengthen grid stability. As responsive loads with quick dynamics, electrolysers operating in HRSs can present flexible balancing services to the power grid. To gain this benefit, this work examines the techno-economic features of providing different frequency grid services by an HRS, considering the possibility of hydrogen injection into the industrial and natural gas pipelines. The ratings of the subcomponents and dispatch plans are optimised to enhance the performance of the plant. A probabilistic mixed-integer linear programming problem is solved over one year with a time resolution of one hour and using real-world historical data based on the European electricity market. The simulation results indicate that the economic profits can be increased significantly as a result of participating in the ancillary service markets and meeting its operation specifications while the stable performance of the HRS is guaranteed.

In Belgium, and many other countries, rooftop solar panels are becoming a ubiquitous form of decentralised energy production. The increasing share of these distributed installations however imposes many challenges on the operators of the low-voltage distribution grid. They must keep the voltage levels and voltage balance on their grids in check and are often regulatory required to provide sufficient reception capacity for new power producing installations. By placing solar panels in different inclinations and azimuth angles, power production profiles can possibly be shifted to align more with residential power consumption profiles. In this article, it is investigated if the orientation of solar panels can have a mitigating impact on the integration problems on residential low voltage distribution grids. An improved simulation model of a solar panel installation is constructed, which is used to simulate the impact on a residential distribution grid. To stay as close to real-life conditions as possible, real irradiation data and a model of an existing grid are used. Both the developed model as the results on grid impact are evaluated.

In Belgium, and many other countries, rooftop solar panels are becoming a ubiquitous form of decentralised energy production. The increasing share of these distributed installations however imposes many challenges on the operators of the low-voltage distribution grid. They must keep the voltage levels and voltage balance on their grids in check and are often regulatory required to provide sufficient reception capacity for new power producing installations. By placing solar panels in different inclinations and azimuth angles, power production profiles can possibly be shifted to align more with residential power consumption profiles. In this article, it is investigated if the orientation of solar panels can have a mitigating impact on the integration problems on residential low voltage distribution grids. An improved simulation model of a solar panel installation is constructed, which is used to simulate the impact on a residential distribution grid. To stay as close to real-life conditions as possible, real irradiation data and a model of an existing grid are used. Both the developed model as the results on grid impact are evaluated.

The energy from solar can easily harnessed to be used for various applications and grid injection. For cooking, different techniques can be utilized. Some people use the sun to cook. Other people use batteries and inverters even at noon. Hence, the cooking system becomes expensive. In fact, Photovoltaic panels did not decrease considerably in price. This paper proposes a simple electronic circuit that a Photovoltaic system can directly be used for cooking. The circuit aims at facilitating a cooking plate user to set a duty ratio. The duty ratio is limited to maintain the array voltage above a minimal level to avoid that it operates too far away from the maximal power point when less power is available. Moreover, it shows to be cost-effective compared to Photovoltaic grid connected and to charcoal.

The energy from solar can easily harnessed to be used for various applications and grid injection. For cooking, different techniques can be utilized. Some people use the sun to cook. Other people use batteries and inverters even at noon. Hence, the cooking system becomes expensive. In fact, Photovoltaic panels did not decrease considerably in price. This paper proposes a simple electronic circuit that a Photovoltaic system can directly be used for cooking. The circuit aims at facilitating a cooking plate user to set a duty ratio. The duty ratio is limited to maintain the array voltage above a minimal level to avoid that it operates too far away from the maximal power point when less power is available. Moreover, it shows to be cost-effective compared to Photovoltaic grid connected and to charcoal.