Forecast of the system frequency response for underfrequency load shedding

2011 ◽  
Author(s):  
U. Rudez ◽  
R. Mihalic
Keyword(s):  
Frequency Response ◽  
Load Shedding ◽  
System Frequency

scholarly journals Fast frequency response of inverter-based resources and its impact on system frequency characteristics

2020 ◽  
Vol 3 (5) ◽  
pp. 475-485
Author(s):  
Lining Su ◽  
Xiaohui Qin ◽  
Shang Zhang ◽  
Yantao Zhang ◽  
Yilang Jiang ◽  
...  
Keyword(s):  
Frequency Response ◽  
Frequency Characteristics ◽  
System Frequency

scholarly journals Detection and localization of multiple small damages in beam

2021 ◽  
Vol 13 (1) ◽  
pp. 168781402098732
Author(s):  
Ayisha Nayyar ◽  
Ummul Baneen ◽  
Syed Abbas Zilqurnain Naqvi ◽  
Muhammad Ahsan
Keyword(s):  
Frequency Response ◽  
Natural Frequencies ◽  
Signal To Noise Ratio ◽  
Moving Average ◽  
A Priori ◽  
Damage Index ◽  
High Signal ◽  
Frequency Range ◽  
Spatial Locality ◽  
System Frequency

Localizing small damages often requires sensors be mounted in the proximity of damage to obtain high Signal-to-Noise Ratio in system frequency response to input excitation. The proximity requirement limits the applicability of existing schemes for low-severity damage detection as an estimate of damage location may not be known  a priori. In this work it is shown that spatial locality is not a fundamental impediment; multiple small damages can still be detected with high accuracy provided that the frequency range beyond the first five natural frequencies is utilized in the Frequency response functions (FRF) curvature method. The proposed method presented in this paper applies sensitivity analysis to systematically unearth frequency ranges capable of elevating damage index peak at correct damage locations. It is a baseline-free method that employs a smoothing polynomial to emulate reference curvatures for the undamaged structure. Numerical simulation of steel-beam shows that small multiple damages of severity as low as 5% can be reliably detected by including frequency range covering 5–10th natural frequencies. The efficacy of the scheme is also experimentally validated for the same beam. It is also found that a simple noise filtration scheme such as a Gaussian moving average filter can adequately remove false peaks from the damage index profile.

A low-order system frequency response model

1990 ◽  
Vol 5 (3) ◽  
pp. 720-729 ◽  
Author(s):  
P.M. Anderson ◽  
M. Mirheydar
Keyword(s):  
Frequency Response ◽  
Order System ◽  
Response Model ◽  
System Frequency ◽  
Low Order

System Frequency Response and Low Voltage Power Factor Correction - A Case Study

2006 ◽  
Author(s):  
M. McGranaghan ◽  
H. Sharma ◽  
D. Murray
Keyword(s):  
Frequency Response ◽  
Power Factor ◽  
Low Voltage ◽  
Power Factor Correction ◽  
System Frequency

Under Frequency Load Shedding Techniques for Future Smart Power Systems

2019 ◽  
pp. 188-202
Author(s):  
H. H. Alhelou
Keyword(s):  
Power Systems ◽  
Power System ◽  
Active Power ◽  
Load Shedding ◽  
System Stability ◽  
Special Focus ◽  
Power Demand ◽  
Synchronous Generators ◽  
Smart Power ◽  
System Frequency

It is critical for today's power system to remain in a state of equilibrium under normal conditions and severe disturbances. Power imbalance between the load and the generation can severely affect system stability. Therefore, it is necessary that these imbalance conditions be addressed in the minimum time possible. It is well known that power system frequency is directly proportional to the speed of rotation of synchronous machines and is also a function of the active power demand. As a consequence, when active power demand is greater than the generation, synchronous generators tends to slow down and the frequency decreases to even below threshold if not quickly addressed. One of the most common methods of restoring frequency is the use of under frequency load shedding (UFLS) techniques. In this chapter, load shedding techniques are presented in general but with special focus on UFLS.

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