A ratio is a comparison of two quantities by division. Oct 28, 2017 physical quantities, measurements standard and units gk physical quantities, measurements standard and units general knowledge general science gs for upsc, ias, banking, railway ssc and other competitive examinations. Per unit system for singlephase transfomers the voltages, currents, powers, impedances, and other electrical quantities are measured as fractions of some base level instead of conventional units. Qup abbreviation stands for quantity per unit pack. The work included in the item is defined in detail by the rules in the method of measurement. Jan 15, 2015 the computation effort in power system is very much reduced with thee use of per unit quantities. Usually, the per unit quantities being of the order of unity or less can easily be handled with a digital computer. Other engineering quantities need a little more thought when writing out the basic mlt dimensions. Per unit system explaination with solved example electrical. Selina concise physics class 7 icse solutions physical. Equipment impedances can be easily estimated since their per unit impedances lie within a relatively narrow range. The per unit value of any quantity is defined as the ratio of the actual value of the any quantity to the base value of the same quantity as a decimal.
Basic radiation interactions, definition of dosimetric quantities, and data sources j. However, if the two quantities are not in the same unit, then we convert them into the same unit before comparison. Atkinson december 2000 nature of bills bills of quantities comprise a list of items of work which are briefly described. When there are large spaces or several similar spaces, the labor productivity for installation increases and the amount of material waste decreases. Introduction to per unit calculations pages 1 11 text. More importantly, while c looks like it is making a loss under traditional costing, abs tells a different story. Vin per unit vin kvv base in kv where the base value is a reference value for magnitude. Two quantities can also be compared using percentages.
Calculation per piece of completely performed item. Chapter 2 quantity takeoff the quantity takeoff is an important part of the cost estimate. The following calculators compute various base and per unit quantities commonly used in the per unit system of analysis by power system engineers. Accepted purchase order quantities per purchase order.
The unit cost for c is 7% lower under abc when compared to traditional costing. For a given quantity voltage, current, power, impedance, torque, etc. A drywall drop soffit is a much higher unit cost than a typical. Units of derived quantities are called derived units. Bill of quantities civil and specialists works for. When quantity shipped to a single destination is less than. For example, if a plane flies 1,920 kilometers in 3 hours, its rate of speed is a ratio that compares the distance traveled to the time that the plane was in. Per unit notation in per unit notation, the physical quantity isin per unit notation, the physical quantity is expressed as a fraction of the reference vava ue. Basic radiation interactions, definition of dosimetric.
Per unit quantities example consider a single phase generating unit rated 50,000 kva at 11,000 volts having an inductive reactance of 0. The determination of per unit values is not the end objective of a study. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Per unit quantities, like percentage quantities, are actually fractional quantities of a reference quantity. If you think you learnt something today then you will love the ebook i. This video discusses basics of perunit quantities and is the first in a series of videos on the subject.
Any quantity is converted into per unit quantity by dividing the numeral value by the chosen base value of the same dimension. Per unit pu quantities the numerical per unit value of any quantity is defined as the ratio of its actual value to another arbitrarily chosen value of quantity of the same dimensions, assumed as the base or reference. In the power systems analysis field of electrical engineering, a perunit system is the expression of system quantities as fractions of a defined base unit quantity. By definition, the per unit value of a quantity is the ratio of the original quantity to its base value which results in a dimensionless per unit or pu value. Define four quantities in per unit of their respective base values. Per unit system practice problem solved for easy understanding. All costs are summed to obtain the total estimated construction cost. Per unit system explaination with solved example free download as. Units of measurement physics class 11 download notes in pdf. Pdf quantities, units and symbols in physical chemistry. Because of an upcoming modernization of the electric system in unit 3 and 4 at. Payment for such excavation is generally at the unit contract price per cubic yard. In this case a standard wall height of 10 per story can be assumed. To find the units done by a crew in an 8hour day, multiply the units per man per.
The per unit value of any quantity is defined as the ratio of actual value in any unit to the base or reference value in the same unit. When two quantities have the same unit of measure, their ratio has no unit of measure. Planners should use this in their initial analysis for forecasting proper requirements and adjust requirements as the oper. The bills also provide a measure of the extent of work and this allows the work to be priced. Var ind sbase 0similarly as in handling the per unit values of ohmic quantities, both real power andreactive power are compared to the apparent base power, usually called base mva. Calculations are simplified because quantities expressed as per unit do not change when they are referred from one side of a.
View notes eng224 lecture 10 per unit system from eng 224 at charles darwin. The speakers are produced in batches because they do not warrant setting up a continuous production line, and relatively large quantities can be produced in a short time. The per unit system permits multiplication and division in addition to addition. The main idea of a per unit system is to absorb large differences in absolute values into base relationships. Dimensions of esu and emu electric and magnetic quantities 5 v. All p and q quantities are three phase voltage magnitudes are. Per unit analysis per unit system power system analysis. Logistics forecasting estimates brigade combat team. I invite you to solve the sample problem at the end of video and leave your answers in the. Page iv wsdot cost estimating manual for projects m 3034.
Speed v meter per second ms m s 1 ms pressure p pascal pa force per unit area kg m 1 s 2 energy e joule j kg m2 s 2 power w watt w energy per unit time kg m2 s 3 a physical quantity can be expressed with a unique combination of 7 base quantities. Comparing quantities class 8 notes maths chapter 8 learn cbse. These have a lot of importance as per unit quantities of parameters tend to have similar values even when the system voltage and rating change drastically. Notes for an introductory course on electrical machines. A power flow study loadflow study is a steadystate analysis whose target is to determine the voltages, currents, and real and reactive power flows in a system under a given load conditions. Certain physical quantities have been chosen as fundamental or base quantities. Description uom quantity unit price total 0100 demolition and dismantling 0101 dismantling of metal doors, windows and partitions, including their removal outside the building and their stacking at a place designated by the investor. The weight of body changes with acceleration due to gravity. Chapter 8 per unit representation sometimes it is more convenient to.
The purpose of the single line diagram is to supply in concise form of the significant information about the system. Units of measurement physics class 11 download in pdf measurement of physical quantities. The per unit system overview page 1 of 6 overview the per unit system is based on the formula shown in equation 1. One can also make a physical quantity with a combination of derived quantities. Unit of mass kilogram the kilogram is the unit of mass. Electric power systems pennsylvania state university. A rate is a special type of ratio comparing two quantities with different units. Further, you can view the aggregated values of these quantities in the header data of these documents. Notes for an introductory course on electrical machines and. Massachusetts institute of technology mit opencourseware.
Chapter 12 quantities, costs, and specifications 12. Buildcost continuously challenge the design, programme, scope and budgets. Jul 04, 2015 this video discusses basics of per unit quantities and is the first in a series of videos on the subject. Ee 423 fault analysis notes university of moratuwa. A rate, like a ratio, is a comparison of two quantities, but the quantities may have different units of measuresand their ratio has a unit of measure. They feed supply to 2 motors of inputs 8 mva and 12 mva respectively. To find the units of work done per man in an 8hour day, divide 8 by the manhours per unit. The computation effort in power system is very much reduced with thee use of per unit quantities. Dimensions and units for physical quantities mksq system 6,7 a. Physical quantities, measurements standard and units gk physical quantities, measurements standard and units general knowledge general science gs for upsc, ias, banking, railway ssc and other competitive examinations. Singlephase per unit system advantages of the per unit system. Per unit pu quantitiesadvantage of per unitrepresentation, one line diagram 2. Now, we note that there will be base quantities for voltage, current and frequency for each of. It must be as accurate as possible and should be based on all available engineering and design data.
In many respects the method is similar to the use of percentage values. Per unit quantities transformer electronics scribd. Lets understand the concept of per unit system by solving an example. It will be easier in the work ahead if we revert to the inverse indice notation and write it as ml3. Unit of time second the second is the duration of 9 192 631 770 pe. Determining quantities per intermediate container quantity icq. The icru has continued to recommend new quantities and units as the need arose, forexample, absorbed dose 1950. In our system the units would be masslength3 or ml3. Calculating food costs, selling prices and making a profit 49 unit 18. A unit rate is a rate that is simplified so that it has a denominator of 1 unit.
Shopping centre anchor unit 900 1,100 per m2 shopping centre shop unit 1,100 1,400 per m2 shopping centre covered mall 1,900 3,000 per m2 buildcost act as our client representative on the refurbishment and fit out of our new head offices. Construction contingency a standardized markup applied to the construction cost of a project that accounts for uncertainties in quantities, unit costs, and minor risk events that typically take place during construction. Accuracy and completeness are critical factors in all cost estimates. Rather determined per unit values serve to assist in the calculation of other system values. Conversion of per unit quantities to volts, ohms, or amperes requires a knowledge of the base that the per unit quantities were referenced to. Perunit system for singlephase transfomers the voltages, currents, powers, impedances, and other electrical quantities are measured as fractions of some base level instead of conventional units. Siebers virginia commonwealth university richmond, virginia usa 2009 aapm summer school. The per unit system is based on the formula shown in equation 1. The numerator of the fraction is called rate per cent. How to estimate the cost of interior building finishes from.
Things in which quantity is measured are known as units. Large quantities the general rule of thumb that there are cost savings for larger volume applies to interior finishes. The quantity of excavation to be paid for is measured as outlined in section 209. Therefore, the speakers are placed into inventory until they are needed for assembly into television.
The perunit system was developed to make manual analysis of power systems easier. Per unit calculation per unit system examples electrical. Use of appropriate automation tools is highly recommended. Accepted purchase order quantities per purchase order and item send feedback. The per unit system is used in power flow, short circuit evaluation, motor starting studies etc. Physics is a quantitative science, based on measurement of physical quantities. The manual is in line with cost estimation system for pbc 2015 hereinafter referred to as costes for pbc 2015, the computer tool used for actual cost estimation exercises. When making multiple portions of food and using ingredients in many different quantities, it is important to be able to calculate ingredient costs accurately. This video discusses basics of perunit quantities and is the first in a series of videos on the. Per unit quantities simply theoretical deduction and give them more generalizes forms. You can display load consumption quantities and normalized quantities in the item details of a freight unit, transportation unit that is, trailer unit, container unit, or package unit, or freight order. A phasor quantity or phasor, provides information about not only the magnitude. Thank you for showing interest in buying our book technical calculation and estimators manhours manual you can buy the electronic v ersion of the manual containing all the figurest and other relat ed data at the following prices. Power flow studies university of nevada, las vegas.
When maxwell first introduced the concept of a coherent system, he identified three quantities that could be used as base units. Description of units mechanical, electric, magnetic 4 iii. How to estimate the cost of interior building finishes. The per unit system is a method of expressing quantities in an electrical system e. Transformers can be replaced by their equivalent series impedances. Figure 3 on page 31 highlights planning factors for this method that are based on the climate. The unit price is then multiplied by the required quantity to find the cost for the work item. Mass per unit volume of a substance is called density of the body. When analyzing a real system, all parameters such as voltage, current, power, and impedance can be converted to per unit. Units and conversion factors table of contents section page references 3 i. What is the abbreviation for quantity per unit pack. The purpose of power flow studies is to plan ahead and account for various hypothetical situations.
Eng224 lecture 10 per unit system per unit quantities. Physical quantities and units university of florida. In this derivation, per unit quantities will usually be designated by lower case letters. This experience suggested there might be other people much like myselfoutside the power industry, but vitally concerned with it. Aug 02, 2018 prebook pen drive and g drive at teacademy. Chapter 6 ratio and proportion huntington union free.
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