An Under Voltage Load Shedding Scheme Based on a Short Term Voltage Instability Detection Method

2018 ◽  
Author(s):  
A. Joseph ◽  
M. Cvetkovic ◽  
P. Palensky
Keyword(s):  
Detection Method ◽  
Load Shedding ◽  
Short Term ◽  
Voltage Instability

New adaptive and centralised under-voltage load shedding to prevent short-term voltage instability

2018 ◽  
Vol 12 (11) ◽  
pp. 2530-2538 ◽  
Author(s):  
Javad Modarresi ◽  
Eskandar Gholipour ◽  
Amin Khodabakhshian
Keyword(s):  
Load Shedding ◽  
Short Term ◽  
Voltage Instability

A Novel Load Shedding Scheme for Voltage Stability

2016 ◽  
Vol 17 (6) ◽  
pp. 649-661 ◽  
Author(s):  
Sunil S. Damodhar ◽  
S. Krishna
Keyword(s):  
Voltage Stability ◽  
Load Shedding ◽  
Short Term ◽  
Voltage Instability ◽  
Local Measurements ◽  
Bus Voltage ◽  
Fast Acting ◽  
Multiple Buses ◽  
Large Disturbance

Abstract Undervoltage load shedding serves to maintain voltage stability when a majority of loads are fast acting. An undervoltage load shedding scheme should address two tasks: the detection of voltage instability following a large disturbance and the determination of the amount of load to be shed. Additionally, in case of short-term voltage instability, the scheme should be fast. This paper proposes a method to predict voltage instability arising due to a large disturbance. The amount of load to be shed to maintain voltage stability is then determined from the Thevenin equivalent of the network as seen from the local bus. The proposed method uses local measurements of bus voltage and power, and does not require knowledge of the network. The method is validated by simulation of three test systems subjected to a large disturbance. The proposed scheme is fairly accurate in estimating the minimum amount of load to be shed to maintain stability. The method is also successful in maintaining stability in cases where voltage collapse is detected at multiple buses.

scholarly journals Small Floating Target Detection Method Based on Chaotic Long Short-Term Memory Network

2021 ◽  
Vol 9 (6) ◽  
pp. 651
Author(s):  
Yan Yan ◽  
Hongyan Xing
Keyword(s):  
High Frequency ◽  
Short Term Memory ◽  
Detection Method ◽  
Low Frequency ◽  
Sea Clutter ◽  
Short Term ◽  
Term Memory ◽  
Memory Network ◽  
Long Short Term Memory ◽  
Small Targets

In order for the detection ability of floating small targets in sea clutter to be improved, on the basis of the complete ensemble empirical mode decomposition (CEEMD) algorithm, the high-frequency parts and low-frequency parts are determined by the energy proportion of the intrinsic mode function (IMF); the high-frequency part is denoised by wavelet packet transform (WPT), whereas the denoised high-frequency IMFs and low-frequency IMFs reconstruct the pure sea clutter signal together. According to the chaotic characteristics of sea clutter, we proposed an adaptive training timesteps strategy. The training timesteps of network were determined by the width of embedded window, and the chaotic long short-term memory network detection was designed. The sea clutter signals after denoising were predicted by chaotic long short-term memory (LSTM) network, and small target signals were detected from the prediction errors. The experimental results showed that the CEEMD-WPT algorithm was consistent with the target distribution characteristics of sea clutter, and the denoising performance was improved by 33.6% on average. The proposed chaotic long- and short-term memory network, which determines the training step length according to the width of embedded window, is a new detection method that can accurately detect small targets submerged in the background of sea clutter.

Automatic Load Shedding Schemes against Voltage Instability in the Hellenic System

2007 ◽  
Author(s):  
V. C. Nikolaidis ◽  
C. D. Vournas ◽  
G. A. Fotopoulos ◽  
G. P. Christoforidis ◽  
E. Kalfaoglou ◽  
...  
Keyword(s):  
Load Shedding ◽  
Voltage Instability

scholarly journals Active and Reactive Power Joint Balancing for Analyzing Short-Term Voltage Instability Caused by Induction Motor

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3617
Author(s):  
Ding Wang ◽  
Yangwu Shen ◽  
Zhen Hu ◽  
Ting Cui ◽  
Xiaoming Yuan
Keyword(s):  
Induction Motor ◽  
Reactive Power ◽  
Movement Direction ◽  
Analysis Method ◽  
Short Term ◽  
Voltage Instability ◽  
Operation Conditions ◽  
Active And Reactive Power ◽  
Acceleration And Deceleration ◽  
Power Balancing

Short-term voltage instability has a sensational effect once it occurs with massive loss of load, possibly area instability, and voltage collapse. This paper analyzes the short-term voltage instability caused by induction motor from the viewpoint of active and reactive power joint balancing. The analysis method is based on (1) the reactive power balancing between system supply and induction motor demand, and (2) the active power balancing between air-gap power and mechanical power, which is expressed by the region of rotor acceleration and deceleration in the Q-V plane. With the region of rotor acceleration and deceleration in the Q-V plane and the reactive power balancing, the movement direction of the operating point can be visually observed in the Q-V plane, thereby achieving a clear comprehension of physical properties behind the short-term voltage instability phenomenon. Furthermore, the instability mechanisms of two kinds of grid-connected induction motor operation conditions after a large disturbance are discussed to explain the basic theory of the analysis method and to provide examples of its application. Time-domain simulations are presented for a single-load infinite-bus system to validate the analyses.

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