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

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.

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1379
Author(s):  
Md Ruhul Amin ◽  
Michael Negnevitsky ◽  
Evan Franklin ◽  
Kazi Saiful Alam ◽  
Seyed Behzad Naderi

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.


Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3879 ◽  
Author(s):  
Ali Bidadfar ◽  
Oscar Saborío-Romano ◽  
Vladislav Akhmatov ◽  
Nicolaos A. Cutululis ◽  
Poul E. Sørensen

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.


2020 ◽  
Author(s):  
Mostafa Malekpour ◽  
Arash Kiyoumarsi ◽  
Mehdi Gholipour

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>


2020 ◽  
Author(s):  
Mostafa Malekpour ◽  
Arash Kiyoumarsi ◽  
Mehdi Gholipour

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>


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