scholarly journals Graph-Theory Based Optimal PMU Allocation Considering ZIB Effects

2020 ◽  
Vol 19 (4) ◽  
pp. 297-300
Author(s):  
Pronob K. Ghosh ◽  
Soumesh Chatterjee ◽  
Anik Tahabilder
Keyword(s):  
Continuous Monitoring ◽  
Operating Conditions ◽  
Graph Theoretic ◽  
Efficient Control ◽  
Minimum Number ◽  
Pmu Placement ◽  
Applied Approach ◽  
A New Technique ◽  
System Graph ◽  
Straightforward Approach

Continuous monitoring is the prerequisite for secure operation and efficient control of power system. This paper presents a new and straightforward approach to monitor the system efficiently. Optimal PMU placement (OPP) deals with the complete system observability with a minimum number of PMU. The Modified Graph theoretic configuration has been presented here to select some strategic locations for PMU installation. Initially, a new technique has been used here to form spanning tree from its system graph. Some standard bus systems i.e. IEEE 7-bus, IEEE 14-bus, and 30-bus have been used to test the effectiveness of the applied approach. The proposed approach has been carried out for normal operating conditions (NOC) as well as considering Zero Injection Bus (ZIB) effects. The simulation result of this efficient and state forward approach has been compared with some other established approaches.

Transcutaneous Oxygen Tension Measurements in Newborn Infants

PEDIATRICS ◽  
1975 ◽  
Vol 55 (2) ◽  
pp. 232-235
Author(s):  
Gosta Rooth
Keyword(s):  
Continuous Monitoring ◽  
Newborn Infants ◽  
Arterial Oxygen ◽  
Invasive Technique ◽  
Clinical Experiences ◽  
Transcutaneous Oxygen Tension ◽  
Transcutaneous Oxygen ◽  
Non Invasive ◽  
Oxygen Tensions ◽  
A New Technique

Attention is called in this brief review article to the development and clinical uses of a new technique for monitoring blood oxygen tensions in newborn infants. This technique uses an electrode recently developed by Huch et al. in Germany to measure arterial oxygen tensions directly through the skin. This device allows for continuous monitoring with a non-invasive technique. The method is now in use in European hospitals. Clinical experiences are cited to document its usefulness.

scholarly journals Fault Diagnosis of PMSG Stator Inter-Turn Fault Using Extended Kalman Filter and Unscented Kalman Filter

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2972 ◽  
Author(s):  
Waseem El Sayed ◽  
Mostafa Abd El Geliel ◽  
Ahmed Lotfy
Keyword(s):  
Kalman Filter ◽  
Fault Diagnosis ◽  
Extended Kalman Filter ◽  
Continuous Monitoring ◽  
Unscented Kalman Filter ◽  
Fault Tolerant ◽  
Synchronous Generator ◽  
Operating Conditions ◽  
Practical Implementation ◽  
Complete Failure

Since the permeant magnet synchronous generator (PMSG) has many applications in particular safety-critical applications, enhancing PMSG availability has become essential. An effective tool for enhancing PMSG availability and reliability is continuous monitoring and diagnosis of the machine. Therefore, designing a robust fault diagnosis (FD) and fault tolerant system (FTS) of PMSG is essential for such applications. This paper describes an FD method that monitors online stator winding partial inter-turn faults in PMSGs. The fault appears in the direct and quadrature (dq)-frame equations of the machine. The extended Kalman filter (EKF) and unscented Kalman filter (UKF) were used to detect the percentage and the place of the fault. The proposed techniques have been simulated for different fault scenarios using Matlab®/Simulink®. The results of the EKF estimation responses simulation were validated with the practical implementation results of tests that were performed with a prototype PMSG used in the Arab Academy For Science and Technology (AAST) machine lab. The results showed impressive responses with different operating conditions when exposed to different fault states to prevent the development of complete failure.

scholarly journals A Bounded Exhaustive Search Technique for Optimal Phasor Measurement Unit Placement in Power Grids

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2021
Author(s):  
Ahmad Asrul Ibrahim ◽  
Khairuddin Khalid ◽  
Hussain Shareef ◽  
Nor Azwan Mohamed Kamari
Keyword(s):  
Search Space ◽  
Exhaustive Search ◽  
Operating Conditions ◽  
Power Grids ◽  
Phasor Measurement Unit ◽  
Computational Time ◽  
Measurement Unit ◽  
Search Technique ◽  
Phasor Measurement ◽  
Pmu Placement

This paper proposes a technique to determine the possible optimal placement of the phasor measurement unit (PMU) in power grids for normal operating conditions. All possible combinations of PMU placement, including infeasible combinations, are typically considered in finding the optimal solution, which could be a massive search space. An integer search algorithm called the bounded search technique is introduced to reduce the search space in solving a minimum number of PMU allocations whilst maintaining full system observability. The proposed technique is based on connectivity and symmetry constraints that can be derived from the observability matrix. As the technique is coupled with the exhaustive technique, the technique is called the bounded exhaustive search (BES) technique. Several IEEE test systems, namely, IEEE 9-bus, IEEE 14-bus, IEEE 24-bus and IEEE 30-bus, are considered to showcase the performance of the proposed technique. An initial Monte Carlo simulation was carried out to evaluate the capability of the bounded search technique in providing a smaller feasible search space. The effectiveness of the BES technique in terms of computational time is compared with the existing exhaustive technique. Results demonstrate that the search space can be reduced tremendously, and the computational burden can be eased, when finding the optimal PMU placement in power grids.

scholarly journals Development of Complex Energy Systems with Absorption Technology by Combining Elementary Processes

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 495 ◽  
Author(s):  
Kosuke Seki ◽  
Keisuke Takeshita ◽  
Yoshiharu Amano
Keyword(s):  
Alternative Energy ◽  
Energy Systems ◽  
Energy System ◽  
Operating Conditions ◽  
Optimal System ◽  
System Configuration ◽  
Bottom Up ◽  
Elementary Processes ◽  
Minimum Number ◽  
Synthesis Methodology

Optimal design of energy systems ultimately aims to develop a methodology to realize an energy system that utilizes available resources to generate maximum product with minimum components. For this aim, several researches attempt to decide the optimal system configuration as a problem of decomposing each energy system into primitive process elements. Then, they search the optimal combination sequentially from the minimum number of constituent elements. This paper proposes a bottom-up procedure to define and explore configurations by combining elementary processes for energy systems with absorption technology, which is widely applied as a heat driven technology and important for improving system’s energy efficiency and utilizing alternative energy resources. Two examples of application are presented to show the capability of the proposed methodology to find basic configurations that can generate the maximum product. The demonstration shows that the existing absorption systems, which would be calculated based on the experience of designers, could be derived by performing optimization with the synthesis methodology automatically under the simplified/idealized operating conditions. The proposed bottom-up methodology is significant for realizing an optimized absorption system. With this methodology, engineers will be able to predict all possible configurations and identify a simple yet feasible optimal system configuration.

On-Line Thermal Balancing Technique for a Large Turbo-Generator

1992 ◽  
Vol 114 (1) ◽  
pp. 60-66 ◽  
Author(s):  
M. Zumbach ◽  
G. Schweitzer ◽  
K. Schoellhorn
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Operating Conditions ◽  
Loop Control ◽  
Turbo Generator ◽  
Closed Loop Control System ◽  
Input Signals ◽  
Loop Control System ◽  
On Line ◽  
A New Technique

In this paper a new technique is proposed to rebalance automatically a large turbo-generator during operation. The sensitivity of the rotor unbalances to thermal asymmetries in the rotor is exploited by mounting some heating elements and using them as actively controlled actuators. The shaft vibrations are measured and used as input signals of the feedback controller. Unbalances thus can be compensated during rotor operation. A theoretical model of the thermo-elastic rotor has been developed and an appropriate closed-loop control system has been designed. The simulation results are verified on a special test rig with digital control allowing for varioius control strategies and various operating conditions.

scholarly journals Test signal generation for service diagnosis based on local structural properties

2012 ◽  
Vol 22 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Michael Ungermann ◽  
Jan Lunze ◽  
Dieter Schwarzmann
Keyword(s):  
Structural Properties ◽  
Test Signal ◽  
Operating Conditions ◽  
Signal Generation ◽  
Theoretic Analysis ◽  
New Approach ◽  
Graph Theoretic ◽  
Signal Selection ◽  
Operating Points ◽  
Structure Graph

Test signal generation for service diagnosis based on local structural propertiesThe paper presents a new approach to the generation of test signals used in service diagnosis. The tests make it possible to isolate faults, which are isolable only if the system is brought into specific operating points. The basis for the test signal selection is a structure graph that represents the couplings among the external and internal signals of the system and the fault signals. Graph-theoretic methods are used to identify edges that disappear under certain operating conditions and prevent a fault from changing the system behavior at this operating point. These operating conditions are identified by validuals, which are indicators obtained during the graph-theoretic analysis. The test generation method is illustrated by a process engineering example.

Forced Diffusion soil flux: A new technique for continuous monitoring of soil gas efflux

2011 ◽  
Vol 151 (12) ◽  
pp. 1622-1631 ◽  
Author(s):  
David Risk ◽  
Nick Nickerson ◽  
Chance Creelman ◽  
Gordon McArthur ◽  
Jennifer Owens
Keyword(s):  
Continuous Monitoring ◽  
Soil Gas ◽  
New Technique ◽  
Forced Diffusion ◽  
A New Technique ◽  
Soil Flux

scholarly journals Experimental Characterization and Evaluation of the Vibroacoustic Field of Hydraulic Pumps: The Case of an External Gear Pump

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6639
Author(s):  
Sangbeom Woo ◽  
Andrea Vacca
Keyword(s):  
Operating Conditions ◽  
Plate Motion ◽  
Sound Power ◽  
Gear Pump ◽  
Experimental Characterization ◽  
Noise Performance ◽  
Noise Sources ◽  
Iso Standards ◽  
Minimum Number

This paper presents the experimental characterization of the vibroacoustic fields and the evaluation of noise performances of hydraulic pumps. Research on hydraulic pump noise has traditionally focused on the fluid-borne noise sources, and very often the analyses of vibration and noise have been performed focusing on a few local points. This trend results in the lack of investigation on the overall behaviors of vibroacoustic fields of hydraulic pumps, and it has been one of the obstacles to understand the complete mechanisms of noise generation. Moreover, despite the existence of the ISO standards for the determination of noise levels, diverse metrics have been used for the evaluation of noise performances of the pumps, but the adequacy of these metrics has not been carefully examined. In this respect, this paper aims at introducing a way to characterize and interpret the measured vibroacoustic field and providing proper methods which are also capable of applying the ISO standards for the fair assessment of pump noise performances. For the characterization of the vibroacoustic field, operational deflection shapes (ODS) and corresponding radiated sound fields are visualized at harmonics of the pumping frequency by using a spectral analysis. Observations are made regarding the motions of the pump and its mounting plate and the resultant radiated noise, depending on the frequency, as well as their correlation. A numerical analysis using the Rayleigh integral equation is also performed to further investigate the contribution of the mounting plate motion on the noise radiation. For the evaluation of noise performance, two different units are tested at multiple operating conditions, and comparisons are made based on their measured sound power levels (SWLs) and sound pressure levels (SPLs). The results emphasize the importance of SWL measurement for the fair noise performance evaluation, and the two methods are proposed as practices to determine the minimum number of measurement points for practicability and to have reliable sound power determination for hydraulic pumps.

A Study of Roughness and Non-Newtonian Effects in Lubricated Contacts

2005 ◽  
Vol 127 (3) ◽  
pp. 575-581 ◽  
Author(s):  
Malal Kane ◽  
Benyebka Bou-Said
Keyword(s):  
Film Thickness ◽  
Numerical Solutions ◽  
Operating Conditions ◽  
Homogenization Theory ◽  
Roughness Effects ◽  
Small Surface ◽  
Lubricated Contacts ◽  
Lubricated Contact ◽  
A New Technique ◽  
Numer Anal

This article is concerned with the simulation of a lubricated contact considering the fluid to be non-Newtonian of the Maxwell type. Severe operating conditions lead to very small surface-to-surface distances. In this situation it is necessary to take roughness effects into account. A popular method consists in averaging the film thickness following Patir and Cheng (ASME J. Lubr. Technol., 100, pp. 12–17, 1978), or more recently Wang et al. (Tribol. Trans., 45(1), pp. 1–10, 2000), with good reported results compared with experimental data. To overcome certain limitations that become apparent at very small film thickness, notably when the roughness is two-dimensional, in 1995 Jai (Math. Modell. Numer. Anal., 29(2), pp. 199–233, 1995) introduced a new technique based on a rigorous homogenization theory in the case of compressible fluid flow. This procedure was further mathematically developed by Buscaglia and Jai (Math. Probl. Eng., 7(4), pp. 355–377, 2001) and applied to tribological problems by Jai and Bou-Saı¨d (ASME J. Tribol., 124, pp. 327–355, 2002). In this paper, we propose a similar homogenized approach in the case of non-Newtonian fluids to avoid numerical problems which are often encountered in other approaches. Results in the homogenized roughness case are obtained and compared with direct numerical solutions.

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