scholarly journals Combined Method of Flow-Reduced Dump Load for Frequency Control of an Autonomous Micro-Hydropower in AC Microgrids

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8059
Author(s):  
Leonardo Peña-Pupo ◽  
Herminio Martínez-García ◽  
Encarna García-Vílchez ◽  
Ernesto Y. Fariñas-Wong ◽  
José R. Núñez-Álvarez
Keyword(s):  
Power Systems ◽  
Flow Control ◽  
Frequency Control ◽  
Experimental Studies ◽  
Load Frequency Control ◽  
Nozzle Flow ◽  
Increase Energy Efficiency ◽  
Water Simulation ◽  
Primary Frequency ◽  
Primary Frequency Control

Nowadays, microgrids (MGs) play a crucial role in modern power systems due to possibility of integrating renewable energies into grid-connected or islanded power systems. The Load Frequency Control (LFC) is an issue of paramount importance to ensure MGs reliable and safe operation. Specifically, in AC MGs, primary frequency control of each energy source can be guaranteed in order to integrate other energy sources. This paper proposes a micro-hydro frequency control scheme, combining the control of a reduced dump load and the nozzle flow control of Pelton turbines operating in autonomous regime. Some works have reported the integration of dump load and flow control methods, but they did not reduce the dump load value and adjust the nozzle flow linearly to the power value demanded by users, causing the inefficient use of water. Simulation results were obtained in Matlab®/Simulink® using models obtained from previous research and proven by means of experimental studies. The simulation of the proposed scheme shows that the frequency control in this plant is done in correspondence with the Cuban NC62-04 norm of power energy quality. In addition, it is possible to increase energy efficiency by reducing the value of the resistive dump load by up to 7.5% in a case study. The validation result shows a 60% reduction of overshoot and settling time of frequency temporal behavior of the autonomous micro-hydro.

scholarly journals Application of Battery Energy Storage Systems for Primary Frequency Control in Power Systems with High Renewable Energy Penetration

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1379
Author(s):  
Md Ruhul Amin ◽  
Michael Negnevitsky ◽  
Evan Franklin ◽  
Kazi Saiful Alam ◽  
Seyed Behzad Naderi
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Power System ◽  
Storage Systems ◽  
Frequency Control ◽  
Battery Energy Storage ◽  
Battery Energy Storage Systems ◽  
Battery Energy ◽  
Primary Frequency ◽  
Primary Frequency Control

In power systems, high renewable energy penetration generally results in conventional synchronous generators being displaced. Hence, the power system inertia reduces, thus causing a larger frequency deviation when an imbalance between load and generation occurs, and thus potential system instability. The problem associated with this increase in the system’s dynamic response can be addressed by various means, for example, flywheels, supercapacitors, and battery energy storage systems (BESSs). This paper investigates the application of BESSs for primary frequency control in power systems with very high penetration of renewable energy, and consequently, low levels of synchronous generation. By re-creating a major Australian power system separation event and then subsequently simulating the event under low inertia conditions but with BESSs providing frequency support, it has been demonstrated that a droop-controlled BESS can greatly improve frequency response, producing both faster reaction and smaller frequency deviation. Furthermore, it is shown via detailed investigation how factors such as available battery capacity and droop coefficient impact the system frequency response characteristics, providing guidance on how best to mitigate the impact of future synchronous generator retirements. It is intended that this analysis could be beneficial in determining the optimal BESS capacity and droop value to manage the potential frequency stability risks for a future power system with high renewable energy penetrations.

scholarly journals Impact of Primary Frequency Control of Offshore HVDC Grids on Interarea Modes of Power Systems

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3879 ◽  
Author(s):  
Ali Bidadfar ◽  
Oscar Saborío-Romano ◽  
Vladislav Akhmatov ◽  
Nicolaos A. Cutululis ◽  
Poul E. Sørensen
Keyword(s):  
Power Systems ◽  
Frequency Control ◽  
Wind Farms ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
Dc Voltage ◽  
Simultaneous Use ◽  
Primary Frequency ◽  
Primary Frequency Control ◽  
The Impact

Offshore high-voltage DC (HVDC) grids are developing as a technically reliable and economical solution to transfer more offshore wind power to onshore power systems. It is also foreseen that the offshore HVDC grids pave the way for offshore wind participation in power systems’ balancing process through frequency support. The primary frequency control mechanism in an HVDC grid can be either centralized using communication links between HVDC terminals or decentralized by the simultaneous use of DC voltage and frequency droop controls. This paper investigates the impact of both types of primary frequency control of offshore HVDC grids on onshore power system dynamics. Parametric presentation of power systems’ electro-mechanical dynamics and HVDC controls is developed to analytically prove that the primary frequency control can improve the damping of interarea modes of onshore power systems. The key findings of the paper include showing that the simultaneous use of frequency and DC voltage droop controls on onshore converters results in an autonomous share of damping torque between onshore power systems even without any participation of offshore wind farms in the frequency control. It is also found that the resulting damping from the frequency control of offshore HVDC is not always reliable as it can be nullified by the power limits of HVDC converters or wind farms. Therefore, using power oscillation damping control in parallel with frequency control is suggested. The analytical findings are verified by simulations on a three-terminal offshore HVDC grid.

scholarly journals An Efficient Adaptive Virtual Inertia Controller for Virtual Synchronous Generators

2020 ◽  
Author(s):  
Mostafa Malekpour ◽  
Arash Kiyoumarsi ◽  
Mehdi Gholipour
Keyword(s):  
Power Systems ◽  
Frequency Control ◽  
Low Frequency ◽  
Adaptive Strategy ◽  
Synchronous Generators ◽  
Low Frequency Oscillation ◽  
Virtual Inertia ◽  
Primary Frequency ◽  
Primary Frequency Control ◽  
Oscillation Damping

This paper proposes an efficient adaptive strategy to control virtual inertia of virtual synchronous generators. This adaptive virtual inertia can provide low frequency oscillation damping and simultaneously improve primary frequency control in power systems. <br>

scholarly journals An Efficient Adaptive Virtual Inertia Controller for Virtual Synchronous Generators

2020 ◽  
Author(s):  
Mostafa Malekpour ◽  
Arash Kiyoumarsi ◽  
Mehdi Gholipour
Keyword(s):  
Power Systems ◽  
Frequency Control ◽  
Low Frequency ◽  
Adaptive Strategy ◽  
Synchronous Generators ◽  
Low Frequency Oscillation ◽  
Virtual Inertia ◽  
Primary Frequency ◽  
Primary Frequency Control ◽  
Oscillation Damping

This paper proposes an efficient adaptive strategy to control virtual inertia of virtual synchronous generators. This adaptive virtual inertia can provide low frequency oscillation damping and simultaneously improve primary frequency control in power systems. <br>

Efficiency of steam turbines with bypass steam distribution for primary frequency control in power systems

2021 ◽  
Vol 5 ◽  
pp. 9-17
Author(s):  
Rashid Aminov ◽  
Alexandr Moskalenko
Keyword(s):  
Power Systems ◽  
Steam Turbine ◽  
Power Unit ◽  
Frequency Control ◽  
Combined Cycle ◽  
Steam Turbines ◽  
Electrical Efficiency ◽  
Primary Frequency ◽  
Primary Frequency Control ◽  
Lower Capacity

This paper evaluates efficiency of steam turbines with bypass steam distribution involved in a process of primary frequency control in power systems. We calculated power of a steam turbine and power unit in general, and absolute electrical efficiency for both bypass and throttle steam distribution. It was found that bypass steam distribution increases absolute electrical efficiency of steam-gas units while operation under lower capacity. Economic indicators calculated for combined cycle gas units confirm effectiveness of steam turbines with bypass steam distribution involved in primary frequency control.

On geographical allocation of primary frequency control reserves in large interconnected power systems

2014 ◽  
Author(s):  
Stavros Karagiannopoulos ◽  
Evangelos Vrettos ◽  
Pablo Centeno Lopez ◽  
Maria Vrakopoulou ◽  
Frauke Oldewurtel ◽  
...  
Keyword(s):  
Power Systems ◽  
Frequency Control ◽  
Interconnected Power Systems ◽  
Primary Frequency ◽  
Primary Frequency Control
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