Isomorphic geodetic and electrical networks: An application to the analysis of airborne gravity gradiometer survey data

Geophysics ◽  
1986 ◽  
Vol 51 (11) ◽  
pp. 2145-2155 ◽  
Author(s):  
Donald H. Eckhardt
Keyword(s):  
Standard Deviation ◽  
Survey Data ◽  
Control Point ◽  
Ground Truth ◽  
Sample Survey ◽  
Electrical Network ◽  
Airborne Gravity ◽  
Gravity Gradiometer ◽  
Electrical Networks ◽  
Gravity Disturbance

Early in 1987, the Bell Aerospace/Textron Gravity Gradiometer Survey System (GGSS) will be tested by the Air Force Geophysics Laboratory in an airborne survey of a 300 × 300 km region of Oklahoma and Texas. The survey pattern will be a grid with a 5 km separation between adjacent tracks, both north‐south and east‐west. One way to process the GGSS survey data is to analyze an electrical network that is isomorphic to the survey network. The integrated gradients between the nodes where the survey lines cross correspond to the applied voltages between the nodes of the electrical network; the gradient variances correspond to the internodal resistances; the elements of the adjusted gravity vector correspond to the nodal voltages; and the solution variances correspond to the resistances to ground. An error analysis is performed by calculating the resistance to ground of the electrical network; a technique for making the calculations in large networks is explored in detail. For sample survey scenarios with one ground‐truth control point near each corner of the survey square and with realistic values for the survey parameters, the standard deviation in the gravity disturbance is less than 1 mGal and the deflection of the vertical standard deviation is less than 0.25 arc-s at all nodes. With no ground truth, but with a gravimeter on the aircraft that can independently determine gravity to 10 mGal at all nodes, the adjusted standard deviation in gravity disturbance is less than 1 mGal.

A review of gravity gradiometer survey system data analyses

Geophysics ◽  
1993 ◽  
Vol 58 (4) ◽  
pp. 508-514 ◽  
Author(s):  
Christopher Jekeli
Keyword(s):  
Field Tests ◽  
Historical Review ◽  
Gravity Anomalies ◽  
Ground Truth ◽  
Airborne Gravity ◽  
Gravity Gradiometer ◽  
Ground Truth Data ◽  
Survey System ◽  
System Data ◽  
Regional Gravity

The Gravity Gradiometer Survey System (GGSS) was designed to measure the local and regional gravity field from a ground or airborne moving platform. With the first and only airborne field test, the GGSS was able to recover five‐arcminute by five‐arcminute mean gravity anomalies to an accuracy of a few mGal. These results were obtained by flying the system, with an operational precision of about 10 Eötvös (ten‐second average), on a grid of orthogonal tracks spaced 5 km apart at an altitude of about 700 m above the terrain. Despite perpetual navigation problems with the Global Positioning System and several periods of excessive system noise, the results of a performance analysis on 19 out of 128 tracks demonstrated the potential accuracy and efficiency of the GGSS as an airborne gravity mapping system. The ground tests (both road and railway), suffering from undue vehicle vibrations and from a lack of ground truth data, were correspondingly less successful, but they also showed no surprises in the system corrupted by these adverse conditions. Unfortunately, the GGSS program has terminated; and it is appropriate to reflect on its accomplishments. Without going into technical details, this somewhat historical review summarizes the field tests, the data reduction algorithms, and the test results, which together portray the breadth of expertise the program engendered in the area of gravity gradiometry.

scholarly journals Optimal feeder reconfiguration in distributed generation environment under time-varying loading condition

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Yanrenthung Odyuo ◽  
Dipu Sarkar ◽  
Lilika Sumi
Keyword(s):  
Graph Theory ◽  
Distributed Generation ◽  
Spanning Tree ◽  
Voltage Stability ◽  
Electrical Network ◽  
List Type ◽  
Network Reconfiguration ◽  
Time Varying ◽  
Electrical Networks ◽  
Tree Algorithm

Abstract The development and planning of optimal network reconfiguration strategies for electrical networks is greatly improved with proper application of graph theory techniques. This paper investigates the application of Kruskal's maximal spanning tree algorithm in finding the optimal radial networks for different loading scenarios from an interconnected meshed electrical network integrated with distributed generation (DG). The work is done with an objective to assess the prowess of Kruskal's algorithm to compute, obtain or derive an optimal radial network (optimal maximal spanning tree) that gives improved voltage stability and highest loss minimization from among all the possible radial networks obtainable from the DG-integrated mesh network for different time-varying loading scenarios. The proposed technique has been demonstrated on a multiple test systems considering time-varying load levels to investigate the performance and effectiveness of the suggested method. For interconnected electrical networks with the presence of distributed generation, it was found that application of Kruskal's algorithm quickly computes optimal radial configurations that gives the least amount of power losses and better voltage stability even under varying load conditions. Article Highlights Investigated network reconfiguration strategies for electrical networks with the presence of Distributed Generation for time-varying loading conditions. Investigated the application of graph theory techniques in electrical networks for developing and planning reconfiguration strategies. Applied Kruskal’s maximal spanning tree algorithm to obtain the optimal radial electrical networks for different loading scenarios from DG-integrated meshed electrical network.

scholarly journals Predicting the influence of the non-sinusoidal network mode on power transformers

2019 ◽  
Vol 114 ◽  
pp. 04005
Author(s):  
Ngo Van Cuong ◽  
Lidiia I. Kovernikova
Keyword(s):  
Service Life ◽  
Electric Power ◽  
Power Quality ◽  
Electrical Equipment ◽  
Operating Conditions ◽  
Transformer Oil ◽  
Power Transformers ◽  
Electrical Network ◽  
Electrical Networks ◽  
Current Harmonics

The parameters of electrical network modes often do not meet the requirements of Russian GOST 32144-2013 and the guidelines of Vietnam. In the actual operating conditions while there is the non-sinusoidal mode in electrical networks voltage and current harmonics are present. Harmonics result in overheating and damage of power transformers since they cause additional active power losses. Additional losses lead to the additional heat release, accelerating the process of insulating paper, transformer oil and magnetic structure deterioration consequently shortening the service life of a power transformer. In this regard there arises a need to develop certain scientific methods that would help demonstrate that low power quality, for instance could lead to a decrease in the electrical equipment service life. Currently we see a development of automated systems for continuous monitoring of power quality indices and mode parameters of electrical networks. These systems could be supplemented by characteristics calculating programs that give out a warning upon detection of the adverse influence of voltage and current harmonics on various electrical equipment of both electric power providers and electric power consumers. A software program presented in the article may be used to predict the influence of voltage and current harmonics on power transformers.

Study of the influence of overvoltage on the quality of electricity in energy systems.

2020 ◽  
Vol 23 (2) ◽  
pp. 52-58
Author(s):  
S. SKRYPNYK ◽  
Keyword(s):  
Power Supply ◽  
Fire Hazard ◽  
Lightning Discharge ◽  
Quality Standard ◽  
Normal Operation ◽  
Electrical Network ◽  
Modern World ◽  
Electrical Networks ◽  
The World

Our world with its high technologies has long been deeply dependent on the quality of electricity supply. In most countries of the world there are national power grids that combine the entire set of generating capacity and loads. This network provides the operation of household appliances, lighting, heating, refrigeration, air conditioning and transport, as well as the functioning of the state apparatus, industry, finance, trade, health services and utilities across the country. Without this utility, namely electricity, the modern world simply could not live at its current pace. Sophisticated technological improvements are firmly rooted in our lives and workplaces, and with the advent of e-commerce began the process of continuous transformation of the way individuals interact with the rest of the world. But with the achievement of intelligent technologies, an uninterrupted power supply is required, the parameters of which exactly meet the established standards. These standards maintain our energy security and create a reliable power system, that is maintaining the system in a trouble-free state. Overvoltage is the deviation of the rated voltage from the value of the corresponding quality standard (frequency, sinusoidal voltage and compliance of harmonics). Overvoltage in terms of fire hazard is one of the most dangerous emergency modes of electrical equipment, which causes conditions that in most cases are sufficient for the occurrence of fire hazards (exceeding the allowable voltage leads to disruption of normal operation or possible ignition). Against the background of deteriorating engineering systems, increased power consumption and poor maintenance, power supply of electrical installations, the main causes of overvoltage in electrical networks are thunderstorms (atmospheric overvoltage), switching switches, uneven phase load in electrical networks, etc. The physical picture of internal overvoltage is due to oscillatory transients from the initial to the established voltage distributions in the conductive sections due to the different situation in the electrical circuit. In the conditions of operation of electric networks planned, mode or emergency situations are possible. Therefore, the ranges of overvoltage are determined by the range from several hundred volts to tens and hundreds of kilovolts, and depend on the types of overvoltage. Atmospheric overvoltage is considered to be one of the most dangerous types of emergency modes of operation of the electrical network. This overvoltage occurs as a result of lightning discharge during precipitation by concentrating electricity on the surface of the object, the introduction of potential through engineering networks and

scholarly journals Validating the Gedex HD-AGG™ Airborne Gravity Gradiometer

2018 ◽  
Vol 2018 (1) ◽  
pp. 1-5 ◽  
Author(s):  
David Hatch ◽  
Hong Wong ◽  
Maria Annecchione ◽  
Shane Hefford
Keyword(s):  
Airborne Gravity ◽  
Gravity Gradiometer

Restricted quasi-score estimating functions for sample survey data

2004 ◽  
Vol 41 (A) ◽  
pp. 119-130
Author(s):  
Y.-X. Lin ◽  
D. Steel ◽  
R. L Chambers
Keyword(s):  
Maximum Likelihood ◽  
Survey Data ◽  
Sample Survey ◽  
Likelihood Method ◽  
Sample Surveys ◽  
Estimating Functions ◽  
Limit Theory ◽  
Normal Probability ◽  
Probability Structure ◽  
Sample Survey Data

This paper applies the theory of the quasi-likelihood method to model-based inference for sample surveys. Currently, much of the theory related to sample surveys is based on the theory of maximum likelihood. The maximum likelihood approach is available only when the full probability structure of the survey data is known. However, this knowledge is rarely available in practice. Based on central limit theory, statisticians are often willing to accept the assumption that data have, say, a normal probability structure. However, such an assumption may not be reasonable in many situations in which sample surveys are used. We establish a framework for sample surveys which is less dependent on the exact underlying probability structure using the quasi-likelihood method.

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