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29-719: (Redirected from Pu ) [REDACTED] Look up PU , Pu , pu , or P U in Wiktionary, the free dictionary. On Misplaced Pages, "PU" may refer to Protected Userpage . PU , Pu , or pu may refer to: Organizations [ edit ] Political parties [ edit ] Ummah Party (Indonesia) ( Partai Ummat ), a political party in Indonesia People and names [ edit ] Pu (Chinese surname) , shared by several people Pu (Indian given name) , shared by several people Pu Ling-en (born 1936),

58-452: A s e {\displaystyle V_{\mathrm {base} }} . We then have: If, for example, the actual voltage at one of the buses is measured to be 136 kV, we have: The following tabulation of per-unit system formulas is adapted from Beeman's Industrial Power Systems Handbook . It can be shown that voltages, currents, and impedances in a per-unit system will have the same values whether they are referred to primary or secondary of

87-409: A transformer . For instance, for voltage, we can prove that the per unit voltages of two sides of the transformer, side 1 and side 2, are the same. Here, the per-unit voltages of the two sides are E 1pu and E 2pu respectively. (source: Alexandra von Meier Power System Lectures, UC Berkeley) E 1 and E 2 are the voltages of sides 1 and 2 in volts. N 1 is the number of turns

116-415: A Dutch video games magazine See also [ edit ] Poo (disambiguation) Peugh (disambiguation) Pue (disambiguation) Pew (disambiguation) Pugh (disambiguation) Pickup (disambiguation) Pull up (disambiguation) All pages with titles beginning with Pu Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

145-453: A common type of plastic pu, a label in the per-unit system of power systems analysis PU learning , a collection of semisupervised techniques in machine learning PU leather or bicast leather, a material made with split leather and polyurethane PU resistor , a pull-up resistor PU scope , a sniper scope of Soviet origin Power unit , component that powers a machine, a vehicle, or

174-456: A convenient system-wide base. Generally base values of power and voltage are chosen. The base power may be the rating of a single piece of apparatus such as a motor or generator. If a system is being studied, the base power is usually chosen as a convenient round number such as 10 MVA or 100 MVA. The base voltage is chosen as the nominal rated voltage of the system. All other base quantities are derived from these two base quantities. Once

203-588: A pen name of British poet J.H. Prynne Pu Yen (1900–2008), Thai centenarian who lived to an age of 108 Yingluck Shinawatra (born 1967), nicknamed Pu, Thai businesswoman and politician Places [ edit ] Pu County , in Shanxi, China Guinea-Bissau , a country in West Africa (NATO country code PU) Province of Pesaro and Urbino , a province in the Marche region of Italy Punjab, India ,

232-1229: A per-unit system depends on whether the system is single-phase or three-phase . Assuming that the independent base values are power and voltage, we have: Alternatively, the base value for power may be given in terms of reactive or apparent power , in which case we have, respectively, or The rest of the units can be derived from power and voltage using the equations S = I V {\displaystyle S=IV} , P = S cos ⁡ ( ϕ ) {\displaystyle P=S\cos(\phi )} , Q = S sin ⁡ ( ϕ ) {\displaystyle Q=S\sin(\phi )} and V _ = I _ Z _ {\displaystyle {\underline {V}}={\underline {I}}{\underline {Z}}} ( Ohm's law ), Z {\displaystyle Z} being represented by Z _ = R + j X = Z cos ⁡ ( ϕ ) + j Z sin ⁡ ( ϕ ) {\displaystyle {\underline {Z}}=R+jX=Z\cos(\phi )+jZ\sin(\phi )} . We have: Power and voltage are specified in

261-729: A state in northern India (postal code PU) Universities [ edit ] In India [ edit ] Panjab University, Chandigarh , a university in India Patna University , a university in Bihar, India Pondicherry University , a central university in Puducherry, India In the United States [ edit ] Parker University , a university in Dallas, Texas, United States Point University ,

290-609: A train. Almost equivalent to an engine. Other uses [ edit ] Pu (Taoism) , early Taoist metaphor for the natural state of humanity PU, an abbreviation for Proto-Ukrainian, an aspect of the Old East Slavic language pu, the Toki Pona name for the book Toki Pona: The Language of Good "Pu", a song by Arca from Kick IIIII pū , the Charonia tritonis PU, an abbreviation of Power Unlimited ,

319-685: A transformer that is rated at 10 kVA and 240/100 V. The secondary side has an impedance equal to 1∠0° Ω. The base impedance on the secondary side is equal to: Z base,2 = V base,2 2 S base = ( 100  V ) 2 10000  VA = 1  Ω {\displaystyle {\begin{aligned}Z_{\text{base,2}}&={\frac {V_{\text{base,2}}^{2}}{S_{\text{base}}}}\\&={\frac {(100{\text{ V}})^{2}}{10000{\text{ VA}}}}\\&={\text{1 }}\Omega \\\end{aligned}}} This means that

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348-748: A university in West Point, Georgia, United States Princeton University , a university in Princeton, New Jersey, United States Purdue University , a university in West Lafayette, Indiana, United States In other countries [ edit ] Purbanchal University , a university in Biratnagar, Nepal University of the Punjab , a public university in Lahore, Pakistan University of

377-418: Is appropriate to illustrate the steps for finding per-unit values for voltage and impedance. First, let the base power ( S base ) of each end of a transformer become the same. Once every S is set on the same base, the base voltage and base impedance for every transformer can easily be obtained. Then, the real numbers of impedances and voltages can be substituted into the per-unit calculation definition to get

406-595: Is different from Wikidata All article disambiguation pages All disambiguation pages PU">PU The requested page title contains unsupported characters : ">". Return to Main Page . Per-unit system The main idea of a per unit system is to absorb large differences in absolute values into base relationships. Thus, representations of elements in the system with per unit values become more uniform. A per-unit system provides units for power , voltage , current , impedance , and admittance . With

435-410: Is used, consider a three-phase power transmission system that deals with powers of the order of 500 MW and uses a nominal voltage of 138 kV for transmission. We arbitrarily select S b a s e = 500 M V A {\displaystyle S_{\mathrm {base} }=500\,\mathrm {MVA} } , and use the nominal voltage 138 kV as the base voltage V b

464-691: The Punjab, Gujranwala , a public university in Gujranwala, Pakistan University of Plovdiv , a public university in Plovdiv, Bulgaria Prešov University , a public university in Prešov, Slovakia Providence University , a university in Taichung, Taiwan Science and technology [ edit ] Plutonium , symbol Pu, a chemical element Processing unit , an electronic circuit that performs operations on some external data source Polyurethane ,

493-446: The answers for the per-unit system. If the per-unit values are known, the real values can be obtained by multiplying by the base values. By convention, the following two rules are adopted for base quantities: With these two rules, a per-unit impedance remains unchanged when referred from one side of a transformer to the other. This allows the ideal transformer to be eliminated from a transformer model. The relationship between units in

522-1427: The base currents I base1 and I base2 are related in the opposite way that V base1 and V base2 are related, in that The reason for this relation is for power conservation The full load copper loss of a transformer in per-unit form is equal to the per-unit value of its resistance: P cu,FL = full-load copper loss = I R 1 2 R e q 1 {\displaystyle {\begin{aligned}P_{\text{cu,FL}}&={\text{full-load copper loss}}\\&=I_{R1}^{2}R_{eq1}\\\end{aligned}}} P cu,FL,pu = P cu,FL P base = I R 1 2 R e q 1 V R 1 I R 1 = R eq1 V R 1 / I R 1 = R eq1 Z B 1 = R eq1,pu {\displaystyle {\begin{aligned}P_{\text{cu,FL,pu}}&={\frac {P_{\text{cu,FL}}}{P_{\text{base}}}}\\&={\frac {I_{R1}^{2}R_{eq1}}{V_{R1}I_{R1}}}\\&={\frac {R_{\text{eq1}}}{V_{R1}/I_{R1}}}\\&={\frac {R_{\text{eq1}}}{Z_{B1}}}\\&=R_{\text{eq1,pu}}\\\end{aligned}}} Therefore, it may be more useful to express

551-461: The base power and the base voltage are chosen, the base current and the base impedance are determined by the natural laws of electrical circuits. The base value should only be a magnitude, while the per-unit value is a phasor. The phase angles of complex power, voltage, current, impedance, etc., are not affected by the conversion to per unit values. The purpose of using a per-unit system is to simplify conversion between different transformers. Hence, it

580-410: The coil on side 1 has. N 2 is the number of turns the coil on side 2 has. V base1 and V base2 are the base voltages on sides 1 and 2. For current, we can prove that the per-unit currents of the two sides are the same below. (source: Alexandra von Meier Power System Lectures, UC Berkeley) where I 1,pu and I 2,pu are the per-unit currents of sides 1 and 2 respectively. In this,

609-417: The exception of impedance and admittance, any two units are independent and can be selected as base values; power and voltage are typically chosen. All quantities are specified as multiples of selected base values. For example, the base power might be the rated power of a transformer , or perhaps an arbitrarily selected power which makes power quantities in the system more convenient. The base voltage might be

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638-445: The nominal voltage of a bus . Different types of quantities are labeled with the same symbol ( pu ); it should be clear whether the quantity is a voltage, current, or other unit of measurement. There are several reasons for using a per-unit system: The per-unit system was developed to make manual analysis of power systems easier. Although power-system analysis is now done by computer, results are often expressed as per-unit values on

667-401: The per unit impedance is 5.76∠0° Ω / 5.76 Ω = 1∠0° pu, which is the same as when calculated from the other side of the transformer, as would be expected. Another useful tool for analyzing transformers is to have the base change formula that allows the engineer to go from a base impedance with one set of a base voltage and base power to another base impedance for a different set of

696-581: The per unit impedance on the secondary side is 1∠0° Ω / 1 Ω = 1∠0° pu When this impedance is referred to the other side, the impedance becomes: Z 2 = ( 240 100 ) 2 × 1∠0°  Ω = 5.76∠0°  Ω {\displaystyle {\begin{aligned}Z_{2}&=\left({\frac {240}{100}}\right)^{2}\times {\text{1∠0° }}\Omega \\&={\text{5.76∠0° }}\Omega \\\end{aligned}}} The base impedance for

725-578: The primary side is calculated the same way as the secondary: Z base,1 = V base,1 2 S base = ( 240  V ) 2 10000  VA = 5.76  Ω {\displaystyle {\begin{aligned}Z_{\text{base,1}}&={\frac {V_{\text{base,1}}^{2}}{S_{\text{base}}}}\\&={\frac {(240{\text{ V}})^{2}}{10000{\text{ VA}}}}\\&={\text{5.76 }}\Omega \\\end{aligned}}} This means that

754-400: The resistance in per-unit form as it also represents the full-load copper loss. As stated above, there are two degrees of freedom within the per unit system that allow the engineer to specify any per unit system. The degrees of freedom are the choice of the base voltage ( V base ) and the base power ( S base ). By convention, a single base power ( S base ) is chosen for both sides of

783-843: The same way as single-phase systems. However, due to differences in what these terms usually represent in three-phase systems, the relationships for the derived units are different. Specifically, power is given as total (not per-phase) power, and voltage is line-to-line voltage. In three-phase systems the equations P = S cos ⁡ ( ϕ ) {\displaystyle P=S\cos(\phi )} and Q = S sin ⁡ ( ϕ ) {\displaystyle Q=S\sin(\phi )} also hold. The apparent power S {\displaystyle S} now equals S base = 3 V base I base {\displaystyle S_{\text{base}}={\sqrt {3}}V_{\text{base}}I_{\text{base}}} As an example of how per-unit

812-463: The title PU . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=PU&oldid=1223014423 " Categories : Disambiguation pages Educational institution disambiguation pages Disambiguation pages with surname-holder lists Hidden categories: Articles containing Hawaiian-language text Short description

841-408: The transformer and its value is equal to the rated power of the transformer. By convention, there are actually two different base voltages that are chosen, V base1 and V base2 which are equal to the rated voltages for either side of the transformer. By choosing the base quantities in this manner, the transformer can be effectively removed from the circuit as described above. For example: Take

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