Reply: New method for digital-computer evaluation of convertor harmonics in power systems using state-variable analysis

1982 ◽  
Vol 129 (3) ◽  
pp. 138
Author(s):  
R.H. Kitchin
Keyword(s):  
Power Systems ◽  
Digital Computer ◽  
New Method ◽  
Computer Evaluation ◽  
State Variable ◽  
Variable Analysis

Mathematical Modeling of Pulsation Dampeners in Fluid Power Systems

2007 ◽  
Author(s):  
Shanzhong Duan ◽  
Mutasim E. Gamal
Keyword(s):  
Power Systems ◽  
New Technologies ◽  
New Method ◽  
Fluid Power ◽  
Pipeline System ◽  
Hydraulic Circuit ◽  
Modeling And Analysis ◽  
Fluid Resistance ◽  
Fluid Systems ◽  
Fluid Power Systems

This paper presents a new method for computer-aided modeling and analyzing of pulsation dampeners used in fluid power systems for vibration reduction. The pulsation dampeners are widely used in various fluid power systems to reduce vibration induced by power pumps. The vibration induced by power pumps in fluid systems may be severe enough to cause the damage of components in pipelines if a pulsation dampener is not installed. However, the current methods used in industries for the design and analysis of the dampeners are manually experience-orientated procedures. They are not adaptable to new technologies. The new modeling method will efficiently automate and improve the current modeling and analysis procedure of various pulsation dampeners with a minimum user effort. The proposed method is a result of utilizing the analogy between electrical circuits and hydraulic circuits. In the new method, a spherical pulsation dampener can be equivalent to a lumped hydraulic circuit installed in a distributed fluid pipeline system. The new method has been developed from the authors’ previous work of an impedance-based model in which only the effect of capacitance and inductance was considered without fluid resistance. In reality, the influence of fluid resistance is significant. This paper will take fluid resistance into considerations and form a resistance-impedance-based model.

scholarly journals A New Method for Computing the Delay Margin for the Stability of Load Frequency Control Systems

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3460 ◽  
Author(s):  
Ashraf Khalil ◽  
Ang Swee Peng
Keyword(s):  
Time Delay ◽  
Power Systems ◽  
Control Systems ◽  
Frequency Control ◽  
Pi Controller ◽  
Load Frequency Control ◽  
New Method ◽  
Load Frequency ◽  
The Stability ◽  
Delay Margin

Open communication is an exigent need for future power systems, where time delay is unavoidable. In order to secure the stability of the grid, the frequency must remain within its limited range which is achieved through the load frequency control. Load frequency control signals are transmitted through communication networks which induce time delays that could destabilize power systems. So, in order to guarantee stability, the delay margin should be computed. In this paper, we present a new method for calculating the delay margin in load frequency control systems. The transcendental time delay characteristics equation is transformed into a frequency dependent equation. The spectral radius was used to find the frequencies at which the root crosses the imaginary axis. The crossing frequencies were determined through the sweeping test and the binary iteration algorithm. A one-area load frequency control system was chosen as a case study. The effectiveness of the proposed method was proven through comparison with the most recent published methods. The method shows its merit with less conservativeness and less computations. The impact of the proportional integral (PI) controller gains on the delay margin was investigated. It was found that increasing the PI controller gains reduces the delay margin.

Modeling and Analysis of Spherical Pulsation Dampeners in Fluid Power Systems

2007 ◽  
Author(s):  
Shanzhong Duan ◽  
Mutasim E. Gamal
Keyword(s):  
Power Systems ◽  
New Technologies ◽  
Vibration Reduction ◽  
New Method ◽  
Fluid Power ◽  
Pipeline System ◽  
Modeling And Analysis ◽  
Fluid Systems ◽  
Computer Aided ◽  
Fluid Power Systems

This paper presents a new method for computer-aided modeling and analyzing of pulsation dampeners used in fluid power systems for vibration reduction. The pulsation dampeners are widely used in various fluid power systems to reduce vibration induced by power pumps. The vibration induced by power pumps in fluid systems may be severe enough to cause the damage of components in pipelines if a pulsation dampener is not installed. However, the current methods used in industries for the design and analysis of the dampeners are manually experience-orientated procedures. They are not adaptable to new technologies. The new modeling method will efficiently automate and improve the current modeling and analysis procedure of various pulsation dampeners with a minimum user effort. The proposed method is a result of utilizing the analogy between electrical circuits and hydraulic circuits. In the new method, a spherical pulsation dampener can be equivalent to a lumped hydraulic circuit installed in a distributed fluid pipeline system. In short, the new method will circumvent some obstacles and introduce new techniques for computer-aided modeling and designing of the dampeners for vibration reduction in fluid power systems.

Sign in / Sign up

Export Citation Format

Share Document