Essentials q() quit. You will be asked if " Save workspace? " type " y " to s... more Essentials q() quit. You will be asked if " Save workspace? " type " y " to save to .RData in current directory <-assign (= also works) help(command1) gives syntax, details & examples Extensions help.start() start browser help apropos("topic1") lists commands relevant to topic1 help.search("topic1") like apropos, but gives short description example(command1) examples of command1 demo(package1) demos related to package1 Numbers and Matrices v1 <-c(1,2,3.4) creates a string of numbers with no dimension 1:3 a string of integers 1,2,3 (with no dimensions) rep(x1,n1) repeats the vector x1 n1 times matrix(v1,r1,c1) make v1 into a matrix with r1 rows and c1 columns. Note: matrices are stored by column. cbind(a1,b1,c1) binds columns into a matrix rbind(a1,b1,c1) binds rows into a matrix dim(matrix1) dimensions of matrix1 length(v1) length of v1 m1[4,3] element of matrix m1 in 4th row, 3rd column m1[,2] column 2 of matrix m1 m1[,2:5] or m1[,c(2,3...
This paper describes the use of substation monitoring systems (power quality monitoring, digital ... more This paper describes the use of substation monitoring systems (power quality monitoring, digital fault recorders, and intelligent relays) for automatic fault location on distribution systems. Fault location algorithms and required system interfaces are described. Two examples of actual ...
A test program was completed to measure arc flash incident energy from actual 480-V utility equip... more A test program was completed to measure arc flash incident energy from actual 480-V utility equipment to determine the most appropriate flame resistant clothing for utility workers. The equipment tested included self-contained and CT-rated meters, padmounted transformer secondary cubicles, power panels, and network protectors. Testing was performed to determine the sustainability of low voltage arcs in actual utility equipment, the most appropriate calculation method to predict the measured incident energy, and to identify any key variables that would effect both duration and heat from this type of equipment.
Arc flash is an important consideration for personnel safety. This paper shows test results for o... more Arc flash is an important consideration for personnel safety. This paper shows test results for overhead arc flash scenarios and arc flash in a padmounted switch. Both scenarios result in more incident energy than expected. For overhead arc scenarios, longer arc lengths are considered when analyzing arc flash. For the padmounted switch, an equation is developed to help coordinate protective clothing with minimum approach distances and upstream protective relaying.
Abstract We use EPRI&#x27;s distribution power quality project data to characterize and predi... more Abstract We use EPRI&#x27;s distribution power quality project data to characterize and predict voltage sags and momentary interruptions based on site characteristics. The quality of sites is widely dispersed. Rural sites have many more sags and momentary interruptions than ...
This paper presents a probabilistic method based on Monte Carlo simulations for assessing the fin... more This paper presents a probabilistic method based on Monte Carlo simulations for assessing the financial feasibility of installing a power quality improvement device at a customer location. The main advantage of this method is that it considers input data as stochastic variables instead of fixed values. Therefore it is possible to calculate all probable outcomes of cost analysis instead of a single possible outcome based on fixed values. An example using the proposed method is presented in the paper. The method can be used by facilities sensitive to voltage sags to judiciously select UPS equipments, DVRs, static transfer switches or other power quality improvement devices.
This paper illustrates the use of resampling bootstrap methods for stochastic prediction of volta... more This paper illustrates the use of resampling bootstrap methods for stochastic prediction of voltage sags from limited monitoring data. Using results from phase II of EPRI's distribution power quality study; we illustrate different resampling techniques that can be used to estimate a system's power quality. These resampling methods are compared with parametric approach, which assumes a certain probability distribution. Resampling
The objective of this project was to assess the specific transformer grounding and connection met... more The objective of this project was to assess the specific transformer grounding and connection methods that are used at the subject utility for distributed generators (DGs) and provide a risk assessment in terms of potential impact, ways to minimize the impact and site specific screening criteria for additional protection that may be required for DG interconnection. The utility has standardized on a grounded wye-grounded wye transformer connection for customers connected to their distribution system. When a backup generator exists in the customer's facility that could be paralleled with the utility system, a contactor is installed on the neutral to ground connection on the generator. This contactor is opened at any time that the generator is paralleled. The utility is considering remotely dispatching these distributed generation assets in times of peak load in the future. This will require the generators to run paralleled for extended periods of time. Grounding practices for auxiliary generators were evaluated, and simulations of both steady-state and fault conditions were conducted. The most critical factors were found to be assuring that the generator ground switch was closed during islanding and that the overvoltage protection operates correctly to isolate the generator during fault conditions. Recommendations for overvoltage protection and testing were developed based upon the results
Page 1. Effect of Single-Phase Reclosing on Industrial Loads Peter E. Sutherland, Senior Member, ... more Page 1. Effect of Single-Phase Reclosing on Industrial Loads Peter E. Sutherland, Senior Member, IEEE Now with GE Energy Services Schenectady, NY 12306 Tom A. Short, Senior Member, IEEE EPRI Solutions, Inc. Schenectady, NY 12305 ...
Page 1. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 45, NO. 1, JANUARY/FEBRUARY 2009 303 Pow... more Page 1. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 45, NO. 1, JANUARY/FEBRUARY 2009 303 Power Quality Assessment of Distributed Generator Grounding Method Peter E. Sutherland, Fellow, IEEE, and Tom A. Short, Senior Member, IEEE ...
Essentials q() quit. You will be asked if " Save workspace? " type " y " to s... more Essentials q() quit. You will be asked if " Save workspace? " type " y " to save to .RData in current directory <-assign (= also works) help(command1) gives syntax, details & examples Extensions help.start() start browser help apropos("topic1") lists commands relevant to topic1 help.search("topic1") like apropos, but gives short description example(command1) examples of command1 demo(package1) demos related to package1 Numbers and Matrices v1 <-c(1,2,3.4) creates a string of numbers with no dimension 1:3 a string of integers 1,2,3 (with no dimensions) rep(x1,n1) repeats the vector x1 n1 times matrix(v1,r1,c1) make v1 into a matrix with r1 rows and c1 columns. Note: matrices are stored by column. cbind(a1,b1,c1) binds columns into a matrix rbind(a1,b1,c1) binds rows into a matrix dim(matrix1) dimensions of matrix1 length(v1) length of v1 m1[4,3] element of matrix m1 in 4th row, 3rd column m1[,2] column 2 of matrix m1 m1[,2:5] or m1[,c(2,3...
This paper describes the use of substation monitoring systems (power quality monitoring, digital ... more This paper describes the use of substation monitoring systems (power quality monitoring, digital fault recorders, and intelligent relays) for automatic fault location on distribution systems. Fault location algorithms and required system interfaces are described. Two examples of actual ...
A test program was completed to measure arc flash incident energy from actual 480-V utility equip... more A test program was completed to measure arc flash incident energy from actual 480-V utility equipment to determine the most appropriate flame resistant clothing for utility workers. The equipment tested included self-contained and CT-rated meters, padmounted transformer secondary cubicles, power panels, and network protectors. Testing was performed to determine the sustainability of low voltage arcs in actual utility equipment, the most appropriate calculation method to predict the measured incident energy, and to identify any key variables that would effect both duration and heat from this type of equipment.
Arc flash is an important consideration for personnel safety. This paper shows test results for o... more Arc flash is an important consideration for personnel safety. This paper shows test results for overhead arc flash scenarios and arc flash in a padmounted switch. Both scenarios result in more incident energy than expected. For overhead arc scenarios, longer arc lengths are considered when analyzing arc flash. For the padmounted switch, an equation is developed to help coordinate protective clothing with minimum approach distances and upstream protective relaying.
Abstract We use EPRI&#x27;s distribution power quality project data to characterize and predi... more Abstract We use EPRI&#x27;s distribution power quality project data to characterize and predict voltage sags and momentary interruptions based on site characteristics. The quality of sites is widely dispersed. Rural sites have many more sags and momentary interruptions than ...
This paper presents a probabilistic method based on Monte Carlo simulations for assessing the fin... more This paper presents a probabilistic method based on Monte Carlo simulations for assessing the financial feasibility of installing a power quality improvement device at a customer location. The main advantage of this method is that it considers input data as stochastic variables instead of fixed values. Therefore it is possible to calculate all probable outcomes of cost analysis instead of a single possible outcome based on fixed values. An example using the proposed method is presented in the paper. The method can be used by facilities sensitive to voltage sags to judiciously select UPS equipments, DVRs, static transfer switches or other power quality improvement devices.
This paper illustrates the use of resampling bootstrap methods for stochastic prediction of volta... more This paper illustrates the use of resampling bootstrap methods for stochastic prediction of voltage sags from limited monitoring data. Using results from phase II of EPRI's distribution power quality study; we illustrate different resampling techniques that can be used to estimate a system's power quality. These resampling methods are compared with parametric approach, which assumes a certain probability distribution. Resampling
The objective of this project was to assess the specific transformer grounding and connection met... more The objective of this project was to assess the specific transformer grounding and connection methods that are used at the subject utility for distributed generators (DGs) and provide a risk assessment in terms of potential impact, ways to minimize the impact and site specific screening criteria for additional protection that may be required for DG interconnection. The utility has standardized on a grounded wye-grounded wye transformer connection for customers connected to their distribution system. When a backup generator exists in the customer's facility that could be paralleled with the utility system, a contactor is installed on the neutral to ground connection on the generator. This contactor is opened at any time that the generator is paralleled. The utility is considering remotely dispatching these distributed generation assets in times of peak load in the future. This will require the generators to run paralleled for extended periods of time. Grounding practices for auxiliary generators were evaluated, and simulations of both steady-state and fault conditions were conducted. The most critical factors were found to be assuring that the generator ground switch was closed during islanding and that the overvoltage protection operates correctly to isolate the generator during fault conditions. Recommendations for overvoltage protection and testing were developed based upon the results
Page 1. Effect of Single-Phase Reclosing on Industrial Loads Peter E. Sutherland, Senior Member, ... more Page 1. Effect of Single-Phase Reclosing on Industrial Loads Peter E. Sutherland, Senior Member, IEEE Now with GE Energy Services Schenectady, NY 12306 Tom A. Short, Senior Member, IEEE EPRI Solutions, Inc. Schenectady, NY 12305 ...
Page 1. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 45, NO. 1, JANUARY/FEBRUARY 2009 303 Pow... more Page 1. IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 45, NO. 1, JANUARY/FEBRUARY 2009 303 Power Quality Assessment of Distributed Generator Grounding Method Peter E. Sutherland, Fellow, IEEE, and Tom A. Short, Senior Member, IEEE ...
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