Optimal Kalman Estimation of Symmetrical Sequence Components

2020 ◽  
Vol 69 (11) ◽  
pp. 8844-8852 ◽  
Author(s):  
Luisa H. B. Liboni ◽  
Mauricio C. de Oliveira ◽  
Ivan N. da Silva
Keyword(s):  
Sequence Components ◽  
Symmetrical Sequence

scholarly journals A Comparative Study of the Voltage Sag Propagation under Un-Symmetrical Faults through Distribution Transformer on Low Voltage Power Network

2021 ◽  
Vol 19 (1) ◽  
pp. 90-94
Author(s):  
Abdul K. Junejo ◽  
Muhammad U. Keerio ◽  
Mohsin A. Koondhar ◽  
Munawar A. Memon ◽  
Muhammad I. Jamali ◽  
...  
Keyword(s):  
Control Strategy ◽  
Low Voltage ◽  
Power Transformers ◽  
Voltage Sag ◽  
Power Network ◽  
Distribution Transformer ◽  
Sequence Components ◽  
The Impact ◽  
Symmetrical Sequence

In this paper, the characterization of the voltage sag propagation under unsymmetrical faults through distribution transformer for low voltage power network is tested with the help of a power analyzer, which is based on sequence components. The voltage sag is a big issue of the power quality (PQ) for the power system networks, which must be analyzed and characterized for the suitable protection schemes and the control strategy, separately. In this study, the voltage sag characterization is fully examined under the unsymmetrical faults through the delta-star with ground (D-Yg) connection, which is commonly imlemented in the distribution power transformers. The MATLAB/Simulink and power analyzer tools are used to characterize the voltage sag propagation. The power analyzer works on the symmetrical sequence component’s method of the voltage. Moreover, the phasor diagram of the voltage sag is also given in this paper for better understanding. The obtained results would help in the design of the protection schemes for low-voltage and controlling the impact of voltage sag through filters.

Conformation takes precedence over sequence in adeno-associated virus DNA replication

1984 ◽  
Vol 4 (7) ◽  
pp. 1416-1419
Author(s):  
R B Lefebvre ◽  
S Riva ◽  
K I Berns
Keyword(s):  
Dna Replication ◽  
Base Sequence ◽  
Adeno Associated Virus ◽  
Symmetrical Sequence

Deletion of an 11-base symmetrical sequence in the inverted terminal repetition of the adeno-associated virus 2 genome inhibits DNA replication. Substitution of either an 8- or a 12-base symmetrical sequence unrelated to the original 11-base sequence restores DNA replication.

scholarly journals Modeling of three-phase electric motor operation by the MATLAB system with deteriorated power quality in the 0.38 kV distribution networks

2018 ◽  
Vol 58 ◽  
pp. 03016 ◽  
Author(s):  
I.V Naumov ◽  
N.V. Savina ◽  
M.V. Shevchenko
Keyword(s):  
Induction Motor ◽  
Power Quality ◽  
Electric Motor ◽  
Distribution Networks ◽  
Negative Sequence ◽  
Operation Modes ◽  
Three Phase ◽  
Sequence Components ◽  
Motor Operation ◽  
The Impact

One of the main operation modes that characterizes power quality in distribution networks is asymmetry of three-phase voltage system. Operation of an induction motor (IM) with disturbed voltage symmetry in the supply network can not be considered as a rated one. The system of voltages applied to the stator winding of IM under these conditions contains positive- and negative-sequence components. This worsens the performance characteristics of IM essentially. In order to balance the 0.38 kV network operation and enhance the efficiency of the three-phase electric motor operation it is suggested to use a special balancing unit (BU) that minimizes the negative-sequence components of current and voltage. The operation modes of the obtained system “supply source – induction motor – balancing unit” are simulated within the MATLAB software package of applied programs, which allows one to assess the impact of low quality of power on the operating characteristics of the electric motor and the efficiency of the balancing unit to increase the “durability” of the motor under the asymmetrical power consumption.

Sequence Component-Based Improved Passive Islanding Detection Method for Distribution System with Distributed Generations

2019 ◽  
Vol 20 (2) ◽  
Author(s):  
Bhatraj Anudeep ◽  
Paresh Kumar Nayak
Keyword(s):  
Distributed Generation ◽  
Distribution System ◽  
Low Cost ◽  
Rate Of Change ◽  
Islanding Detection ◽  
Detection Scheme ◽  
Small Power ◽  
Distributed Generations ◽  
Sequence Components ◽  
Detection Schemes

Abstract In distributed generation (DG) systems, the rate of change of voltage and the rate of change of frequency are the two most common and widely used simple and low-cost passive islanding detection schemes. Unfortunately, these passive islanding detection schemes find limitation for detecting the islandings that cause very small power imbalance. In this paper, an improved passive islanding detection scheme is proposed by using the two newly derived indices from the sequence components of the current signal with the conventional voltage and frequency parameters. The performance of the proposed scheme is tested for numerous islanding and non-islanding cases generated on IEEE Std 399–1997 and IEC microgrid model distribution system integrated with both inverter-interfaced and synchronous DGs through PSCAD/EMTDC. The obtained results confirm the effectiveness of the proposed scheme.

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