Relay Coordination Algorithm with Limits on Minimum Operating Time of customized Time Inverse Relays Characteristics

2021 ◽  
Author(s):  
Manohar Singh
Keyword(s):  
Operating Time ◽  
Relay Coordination ◽  
Minimum Operating

Sympathetic Trippings Blocking in Over Current Relay Coordination Algorithm during Steady State & Transient Network Topologies

2016 ◽  
Vol 17 (3) ◽  
pp. 311-326 ◽  
Author(s):  
Manohar Singh ◽  
B.K. Panigrahi ◽  
T. Vishnuvardhan
Keyword(s):  
Distribution System ◽  
Search Algorithm ◽  
Operating Time ◽  
Network Configuration ◽  
Coordination Problem ◽  
Relay Coordination ◽  
Network Topologies ◽  
Time Gap ◽  
Transient Network ◽  
Nuisance Tripping

Abstract In this paper an improved over current relay coordination protection technique is proposed. The proposed technique eliminates the sympathetic/nuisance tripping in an interconnected distribution system. Nuisance trippings are eliminated by incorporating the additional selectivity constraints in conventional over current relay coordination problem. Whenever the fault is cleared only from one end of the line in bidirectional fault feed lines, transient network configuration comes into existence. Transient network configuration causes the redistribution of fault in the distribution system and leads to further nuisance tripping of relays. This problem in this paper is solved by minimising the operating time gap between primary relays located at near end and far end of a faulty line to the best minimum possible value. The differential search algorithm is applied for optimization of highly non-linear over current relay coordination problem in this paper. The result presented in this paper shows that the proposed over current relay coordination technique is immune against the sympathetic/nuisance tripping and operating time difference between primary relays at near end and far end is also minimised within acceptable time margin successfully.

scholarly journals Integrated Dwt-Differentiation Algorithm for Fault Detection and Relay Coordination in Micro Grid

2019 ◽  
Vol 9 (2) ◽  
pp. 4365-4370
Keyword(s):  
Fault Detection ◽  
Operating Time ◽  
Discrete Wavelet ◽  
Fault Current ◽  
Relay Coordination ◽  
Optimization Function ◽  
Input Waveform ◽  
Differential Algorithm ◽  
Bidirectional Flow ◽  
Effective Analysis

The Bidirectional flow of current makes it difficult to detect fault in the microgrid. The level of fault current changes continuously with change in load, it leads to selectivity and sensitivity issue of relay. In this paper integrated DWT-differentiation algorithm is proposed for fault detection and relay coordination, the input waveform of fault current is proceed with discrete wavelet transform. Time scale function of DWT used to extract exact feature from signal which helps in further effective analysis. The Optimization function of relay is mainly depends on PSM (plug setting multiplier) and TDS (Time dial span). The Fault current used to calculate this parameter are already analyzed from DWT. Standard 9 bus IEEE system is used as reference. Fault is detected at 21 different locations; initially primary protection is activated and secondary protection operates only if first selected pair of relay fails to operate .The differential algorithm select best pair of backup relay and relay coordination is carried out resulting in reduction of operating Time

METHOD FOR CALCULATING THE RELIABILITY OF QUARTZ RESONATORS

2020 ◽  
pp. 53-58
Author(s):  
M. I. Boychuk ◽  
L. A. Vasileva ◽  
S. A. Mikaeva
Keyword(s):  
Operating Time ◽  
Quartz Resonator ◽  
Test Time ◽  
Frequency Change ◽  
Piezoelectric Resonators ◽  
Reliability Indicators ◽  
Resonator Frequency ◽  
The Stability ◽  
Work Done ◽  
Minimum Operating

In the process of developing a thermocompensated quartz generator, it was necessary to calculate the reliability indicators of such an important element of the circuit as a quartz resonator for a failure-free period of 15 000 hours. The main parameter that can be used to evaluate the reliability of the quartz resonator is the stability of the nominal oscillation frequency. It is the stability of the nominal frequency of the resonator that formed the basis of the new developed technique. The method includes rules for constructing a probabilistic and statistical model of the dependence of the resonator frequency change on the test time. The article describes the work done on the accelerated evaluation of the reliability of piezoelectric resonators RK563 on the basis of probabilistic and statistical modeling of the behavior of the frequency from the test time. The method of mathematical modeling is based on the results of incomplete tests for a period of 30…50 % of the set value of the minimum operating time.

scholarly journals An Optimized Adaptive Protection Scheme for Numerical and Directional Overcurrent Relay Coordination Using Harris Hawk Optimization

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5603
Author(s):  
Muhammad Irfan ◽  
Abdul Wadood ◽  
Tahir Khurshaid ◽  
Bakht Muhammad Khan ◽  
Ki-Chai Kim ◽  
...  
Keyword(s):  
Optimization Problem ◽  
Operating Time ◽  
Global Optimum ◽  
Electrical Network ◽  
Coordination Problem ◽  
Protection Scheme ◽  
Decision Variables ◽  
Impressive Result ◽  
Relay Coordination ◽  
Overcurrent Relay

The relay coordination problem is of dire importance as it is critical to isolate the faulty portion in a timely way and thus ensure electrical network security and reliability. Meanwhile a relay protection optimization problem is highly constraint and complicated problem to be addressed. To fulfill this purpose, Harris Hawk Optimization (HHO) is adapted to solve the optimization problem for Directional Over-current Relays (DOCRs) and numerical relays. As it is inspired by the intelligent and collegial chasing and preying behavior of hawks for capturing the prey, it shows quite an impressive result for finding the global optimum values. Two decision variables; Time Dial Settings (TDS) and Plug Settings (PS) are chosen as the decision variables for minimization of overall operating time of relays. The proposed algorithm is implemented on three IEEE test systems. In comparison to other state-of-the-art nature inspired and traditional algorithms, the results demonstrate the superiority of HHO.

System Availability Test Procedure with Minimum Operating Time

2013 ◽  
Vol 706-708 ◽  
pp. 2053-2056
Author(s):  
Kang Fu ◽  
Ying Xu ◽  
Jun Yang ◽  
Wei Zhang
Keyword(s):  
Sample Size ◽  
Test Procedure ◽  
Operating Time ◽  
Repair Process ◽  
System Availability ◽  
Test And Evaluation ◽  
Minimal Sample ◽  
Fixed Sample ◽  
Minimal Sample Size ◽  
Minimum Operating

In order to solve problem about how to test inherent availability of repairable system under minimum operating time and lognormal repair time, an inherent availability test procedure with fixed sample size is presented. The test procedure which is divided into alternate operating and repair process, should meet stated levels of producer’s risk and consumer’s risk. It is noticeable that minimal sample size and critical value calculation method research is considered as the key point of procedure design. At the end of this paper, course of a test procedure design and operation of inherent availability test and evaluation are described by example analysis.

scholarly journals Optimal over Current Relay Coordination of IEEE 9 Bus System using Mipower

2020 ◽  
Vol 8 (5) ◽  
pp. 1481-1485
Keyword(s):  
Power System ◽  
Short Circuit ◽  
Operating Time ◽  
Test System ◽  
Load Flow ◽  
Circuit Analysis ◽  
Main Function ◽  
Relay Coordination ◽  
Protective Relays ◽  
Short Circuit Analysis

The protective system plays a major role which has great effect on the power system operation. The modern interconnected power system consists of large numbers of protective relays and circuit breakers which constitute an integral part of the protective scheme. The main function of the relay is to sense and locate the fault and sends a command to the breaker to isolate the faulty element. The objective of the relay coordination is to provide primary as well as backup protection from any fault that is likely to occur in the power system. In this paper, overcurrent relay coordination is implemented on an IEEE 9 Bus test system using MiPower software for phase and earth faults. The Load flow analysis and the short circuit analysis on the IEEE 9 Bus test system is initially done followed by relay coordination. Fault MVA and Fault current data obtained from short circuit analysis enables us to obtain operating time of the relays used in the test system. The calculated value of operating time gives the coordinated operation of all the relays. The MiPower software has unique feature which is very useful in proper coordination of overcurrent relays.

scholarly journals Development of Abrasive Grain Coating Technology Protective Polymer Casing for Water-Abrasive Cutting

2022 ◽  
Author(s):  
O.G. Kozhus
Keyword(s):  
Operating Time ◽  
Polymer Shell ◽  
Coating Technology ◽  
Abrasive Grain ◽  
Quality Product ◽  
Processing Modes ◽  
Protective Polymer ◽  
Minimum Operating ◽  
Abrasive Cutting ◽  
High Quality Product

Abstract.The article presents the technology of covering abrasive grains with a protective polymer shell, which allows to reduce the wear of the focusing tube of the nozzle of a hydroabrasive installation. A description of the manufacturing process of a prototype abrasive with a polymer coating in a fluidized bed is presented in order to determine the critical processing modes at which a high-quality product will be obtained in a minimum operating time of the installation.

Role of Closed Mitral Commissurotomy for Mitral Stenosis: Mid- and Long-term Surgical Outcome of 36 Patients

2005 ◽  
Vol 8 (1) ◽  
pp. 55 ◽  
Author(s):  
Azman Ates ◽  
Yahya �nl� ◽  
Ibrahim Yekeler ◽  
Bilgehan Erkut ◽  
Yavuz Balci ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Mitral Stenosis ◽  
Operating Time ◽  
Term Survival ◽  
Long Term Outcome ◽  
Mitral Commissurotomy ◽  
Closed Mitral Commissurotomy

Purpose: To evaluate long-term survival and valve-related complications as well as prognostic factors for mid- and long-term outcome after closed mitral commissurotomy, covering a follow-up period of 14 years. Material and Methods: Between 1989 and 2003, 36 patients (28 women and 8 men, mean age 28.8 6.1 years) underwent closed mitral commissurotomy at our institution. The majority of patients were in New York Heart Association (NYHA) functional class IIB, III, or IV. Indication for closed mitral commissurotomy was mitral stenosis. Closed mitral commissurotomy was undertaken with a Tubbs dilator in all cases. Median operating time was 2.5 hours 30 minutes. Results: After closed mitral commissurotomy, the mitral valve areas of these patients were increased substantially, from 0.9 to 2.11 cm2. No further operation after initial closed mitral commissurotomy was required in 86% of the patients (n = 31), and NYHA functional classification was improved in 94% (n = 34). Postoperative complications and operative mortality were not seen. Follow-up revealed restenosis in 8.5% (n = 3) of the patients, minimal mitral regurgitation in 22.2% (n = 8), and grade 3 mitral regurgitation in 5.5% (n = 2) patients. No early mortality occurred in closed mitral commissurotomy patients. Reoperation was essential for 5 patients following closed mitral commissurotomy; 2 procedures were open mitral commissurotomies and 3 were mitral valve replacements. No mortality occurred in these patients. Conclusions: The mitral valve area was significantly increased and the mean mitral valve gradient was reduced in patients after closed mitral commissurotomy. Closed mitral commissurotomy is a safe alternative to open mitral commissurotomy and balloon mitral commissurotomy in selected patients.

Sign in / Sign up

Export Citation Format

Share Document