0000002504 00000 n Solution The system of Fig. Here’s our simple TNEB Bill calculator and TNEB Tariff calculator ( unit slab list ) for electricity consumers in Tamil Nadu. { Electricity will cost more by 15-20 paise per unit for domestic consumers in Himachal Pradesh with the state electricity regulatory commission … Fuel cost You can find new, Often, nameplate values are taken as base values but this need not be the case. 0000025728 00000 n 0000026395 00000 n 0000007151 00000 n 1 can be subdivided into different sections with different voltage levels determined by the transformer turns ratios. } Determine I base, Z base, and Y base. Therefore, the power delivered by three phase is much more consistent and supply more power than a 3 single-phase power … The range for acceptable % or p.u. Some of these advantages are highlighted as follows: Modern power systems comprise several transmission lines interconnected in subsystems of different voltage levels through various step-up or step-down transformers. The non-fuel cost is the cost of generating and delivering electricity to homes. Did you find apk for android? 0000003039 00000 n {{I}_{base}}$, \[{{I}_{base}}=\frac{{{S}_{base}}}{{{V}_{base}}\times \sqrt{3}}\], \[{{Z}_{base}}=\frac{{{V}_{base}}}{{{I}_{base}}\times \sqrt{3}}=\frac{V_{base}^{2}}{{{S}_{base}}}\], In general, the per unit values are determined as, $\begin{align}  & {{V}_{pu}}=\frac{V}{{{V}_{base}}} \\ & {{I}_{pu}}=\frac{I}{{{I}_{base}}} \\ & {{S}_{pu}}=\frac{S}{{{S}_{base}}} \\ & {{P}_{pu}}=\frac{P}{{{P}_{base}}} \\ & {{Z}_{pu}}=\frac{Z}{{{Z}_{base}}} \\ & {{Y}_{pu}}=\frac{Y}{{{Y}_{base}}} \\\end{align}$. 0000022073 00000 n 0000015963 00000 n The per unit (PU or P.U.) "@id": "https://electricalacademia.com", I told them that I have a set of high tension power lines on part of my property and all I have to do is put a pole up with a transformer and I can have free electric for life for that price. Example: The above motor is operated 18 hours per day. } 0000024743 00000 n Now #3800 divided by 74.8 is about 50.8kwh per unit. In this case, your electricity bill will look like this: Fixed charge: Rs 20 (single phase) Cost for 260 units: 260 x Rs 5.00 = Rs 1,300 (flat rate for every unit consumed) Three phase and single phase are electricity supplies and it’s the amount of power that is different. Using the common base, The three-phase load at bus 4 absorbs 60 M, Voltage base for buses 1, 2, and 3:${{V}_{b}}\left( 1 \right)={{V}_{b}}\left( 2 \right)={{V}_{b}}\left( 3 \right)=110kV$, Voltage base for bus 4: ${{V}_{b}}\left( 4 \right)=11kV$, Per-unit reactances of the generators and transformers are, In all of these expressions, the numerator is a complex vector, whereas the denominator is a real number. The per-unit representation of physical values consists in expressing these values as fractions or percentages of some representative bases of the same physical nature. If you require two or more electricity meters then you need a three phase supply. A per unit quantity then becomes the ratio of a selected parameter to a selected base value. I would also imagine that the minimum conduit size would be such that it allows for a single or three phase supply to be run through it. This way, there is less chance of confusing line and phase voltages as well as between single- and three-phase power systems. However, because they are interrelated, selecting base values for any two of them determines the base values of the remaining two. More specifically, the per unit method of calculation is often used in the calculation of short circuit currents. The final bill cost is 756.6 /- LT C Category Tariff rates more than 200 units: When your consumption is more than 200 units mean, then you have to pay LT C category. In equations to calculate power and voltage in three-phase systems, the factors $\sqrt{3}$  and 3 are eliminated using the PU system. Electricity unit price is different for each plan, here I’m sharing the electricity unit price of domestic connection. The state that saw the great increase in prices for electricity is Rhode Island. Consider a three-phase transformer with a rating of 700 MVA and a secondary voltage of 145 kV. "position": 2, 0000015543 00000 n However, this makes it difficult to figure out the various voltage and power levels at different points in the network. 3 phase power supply contains three individual AC waveform with 120° difference between them. Online calculator to calculate the daily or monthly usage cost of your air conditioning unit. I imagine the pit would have three phase power running through it, so cant see any issues there. As an example of how per-unit 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. The fuel cost, or cost of imported natural gas, is tied to oil prices by commercial contracts, which change depending on global market conditions. 0000003085 00000 n For transmission lines, 100 MVA is often used. To overcome this problem, all the system quantities are converted into a uniform normalized platform called per-unit. "@type": "BreadcrumbList", Unless maybe the meter is owing some debts which Ikeja deducts each time he vends. startxref 3 Unit costs exclude generator's responsibility for Income Tax Component of Contribution (ITCC), (will be added to total cost estimates, if required) 4 Unit costs exclude environmental monitoring and mitigations 5 Unit Costs assume that operational clearances are available as required. "name": "Electric Power" },{ The three-phase load at bus 4 absorbs 60 MVA at 0.75 power factor (lagging), and lines 1, 2, and 3 have the reactance of 40Ω, 32 Ω, and 30Ω, respectively. \$\begingroup\$ If you need high power you should take the 3 phase system, like you said 2kW Motor, for low power devices you should take the single phase because you have lower costs for converting it into dc for example. 0000026747 00000 n Three-phase electric power is a common method of alternating current electric power generation, transmission, and distribution. "item": Three phase electricity is common in both larger homes and businesses, and allows for smaller, less expensive wiring, and lower voltages. For example, if the base value of voltage had been selected as 13,800 V and the present value is 11,000 V, the value of voltage per unit is. Determine Ibase, Zbase, and Ybase. To overcome this problem, all the system quantities are converted into a uniform normalized platform called, The per-unit representation of physical values consists in expressing these values as fractions or percentages of some representative, Electricity Tariffs Explained | Residential and Industrial Tariff, Grounding Electrical System | Purpose of Grounding Electrical Systems. "position": 3, "@id": "https://electricalacademia.com/category/electric-power/", For base values, a value of Sbase = 50 or 100 MVA is often selected. Three phase costs me (5.5 x .14 x 6) per day to operate or ($4.62) a difference of $2.03/day. } ] The impedance diagram of the system with all reactances in PU is plotted in Fig. Often, nameplate values are taken as base values but this need not be the case. It is a factor of the transformer ratios. Using the transformer’s rated values of apparent power and secondary voltage. 100 0 obj <> endobj Multiply the total kilowatt hours used by the rate per kilowatt hour charged by the power company to find the cost. "itemListElement": Hence, for first 100 units the per unit cost will be ₹ 3.3 and the next 85 units the per unit cost will be ₹ 4.3. In all of these expressions, the numerator is a complex vector, whereas the denominator is a real number. It is often convenient to express these values in a common system basis. 0000002371 00000 n 0000004489 00000 n Table of Content1 TNEB Bill Calculator 20202 TNEB Tariff Details 2020-20212.1 How to Calculate […] 0000008328 00000 n KW, KVA KW is real consumed power turned into heat, and is the product of volts x current x power factor. 0000003365 00000 n "name": "Per Unit Calculation | Per Unit System Examples" Any two variables are selected to be base values. values can be easily fixed. The PU system deals primarily with values of power, voltage, current, and impedance. PU impedance of the transformer is independent of the kV base. The determination of per unit values is not the end objective of a study. While the actual values of the impedances of power system equipment, expressed in ohms, may vary over a wide range, depending on their rating, their per-unit values are restricted to a narrow range whatever the rating may be. 0000005113 00000 n Example: Motor 10 HP, 460V, 3 phase, find I NEC 430-150, 10 HP @ 460V, 3 phase I = 14 Amp 3. Duty is applicable per unit of electricity consumption and tax is applied on the whole bill amount. "url": "https://electricalacademia.com/category/electric-power/", }. The corresponding values of Ibase, Zbase, and Ybase are readily determined. Selected values of parameters are compared to selected base values and assigned per unit values. The Ac Operating Cost is calculated based on the factors like Equipment Size, Electric Rate, Cooling Hours and SEER (Seasonal Energy Efficiency Ratio). �E/G�I�]+�_p�r)�5. 0000024875 00000 n "@context": "http://schema.org", There is no obligation to choose the transformer’s ratings as the base values, but it is an option. However, this makes it difficult to figure out the various voltage and power levels at different points in the network. The PU system is very useful for computer-performed calculations concerning steady-state and dynamic analysis. 0000003411 00000 n { Basically, Per Unit = (Present value) ÷ (base value), Per Unit values are sometimes expressed as a percentage rather than a ratio. The manufacturer’s nominal ratings are given as follows: FIGURE 1 Single-line diagram of Example 1. 0000006306 00000 n 0000002926 00000 n These have not been included in this study as many SWER lines do not require a voltage regulator and the need for a voltage regulator is based on individual system characteristics and studies. I also need the slab rates like how much cost per unit for 0-100 units,100-200 units,200-300 units etc.I heard that we will get electric bill bi-monthly.But my landlord takes electric bill every month.He is insisting me to pay Rs 6/unit for every month (even if consumption is < 100 units) He told 3-phase power will come under commercial purpose, so the charge will be more.Is it true? <]>> 4) Meter Rent: Rent that you pay for having a meter at your home. This arrangement produces a smoother power flow and permits lower line voltages. Per Unit System Example of Three Phase System. Now the current per phase is also down to a third of what it would be with a single phase supply (about 30 amps per phase, rather than 100). There are many advantages to use the per-unit system in power network engineering as such representation results in more correlated and meaningful data. },{ A single phase supply is smaller than a three phase supply. Determine I, The single-line diagram of a three-phase system is shown in Fig. "name": "Home" "item": %PDF-1.4 %���� Figure 7 – Delta connection – three phase, three wires. 1. Calculate the total cost. Business size Annual electricity usage (kWh) Unit price per kWh; Micro business: 5,000 - 15,000: 14.4p - 15.9p: Small business: 15,000 - 25,000: 14.3p - 15.1p To change base values, the following expression is used: \[{{Z}_{pu-new}}={{Z}_{pu-old}}\times \left( \frac{{{S}_{base-new}}}{{{S}_{base-old}}} \right){{\left( \frac{{{V}_{base-old}}}{{{V}_{base-new}}} \right)}^{2}}\]. "@type": "ListItem", } The only additional cost of 3 phase is the initial connection – more cores = more cost. 0000000016 00000 n Determine the electricity cost per unit. For in-house electrical systems, a base of Sbase = 10 MVA is more suitable as the VA values are generally smaller than the VA of overland transmission lines. Go back to Three phase power measurements ↑ Wye and Delta comparison. 0000006607 00000 n 0000008168 00000 n Vb(L-L) is the line-to-line base voltage, which is not constant for the entire network. > approximate cost per unit of 3 phase electricity. Home » Electric Power » Per Unit Calculation | Per Unit System Examples { Per unit notation In per unit ... total 3total 3-phase power S = Sphase power S = S 3- line voltage V = V line line current I = I line equivalent impedance/phase Z = Z ph with (in magnitude) VV = √3ZI;S =√3VI. Especially useful in networks with multiple voltage levels interconnected through transformers. There is no obligation to choose the transformer’s ratings as the base values, but it is an option. The per unit method uses what are called base values. Base Value for 3-ppyhase systems For either a single-phase system or a three-phase system, the per units become, $\begin{align}  & {{V}_{pu}}=\frac{V}{{{V}_{base}}} \\ & {{I}_{pu}}=\frac{I}{{{I}_{base}}} \\ & {{S}_{pu}}=\frac{S}{{{S}_{base}}} \\ & {{Z}_{pu}}=\frac{Z}{{{Z}_{base}}} \\\end{align}$. Four base quantities, namely power, voltage, current, and impedance, are necessary for the full description of a per-unit system. 0000026073 00000 n In contrast, three-phase power has four wires, three of which are active, in addition to one neutral wire, which is once again earthed at the switchboard. x�b```f``Y������� Ȁ �@16�� !�lߠr@HA�A�����L���;�*00�`-`���ͨ�P}`��A� &��}���^��޶��}�o6U>g� Xx��6t����6�K.z{6ڲNLU�Z&W��0I\}Q���J4��Y�k��j�o��/|���v$Os�?�sV�-�m�F^"I'd���6�tT �^׹�I狙Ǐ�4��lj1y�zߙ��-��"WBS�E��U�es����%��J�i g?�]+����"td�z���ϛ2n�u�m=��s�K��M�ћ��7lY"cS&F�.���$)_�:�~��ȅs*^�%��9�f x�N -�]x3�NR}Q��]7$N)rZlН�;_�L��1����v;k(� L�ۭ�|!Qd��kT���I��2�.} 0000003179 00000 n "url": "https://electricalacademia.com", Some basic relationships follow and are different for, Consider a three-phase transformer with a rating of 700 MVA and a secondary voltage of 145 kV. Some basic relationships follow and are different for single-phase systems and three-phase systems. Nevertheless, any value of S may be used. 0000026494 00000 n Usually, power, Sb, and voltage, Vb, are chosen as base values for computing the current, Ib, and impedance, Zb, bases: \[{{I}_{b}}=\frac{{{S}_{b\left( 3\varphi  \right)}}}{\sqrt{3}{{V}_{b\left( L-L \right)}}}\], \[{{Z}_{b}}=\frac{{{\left( {{V}_{b\left( L-L \right)}}\text{ in kV} \right)}^{2}}}{{{S}_{b\left( 3\varphi  \right)}}\text{ in MVA}}\]. Hence, the load impedance in Ω is, \[{{Z}_{Load}}=\frac{{{V}^{2}}}{S_{L}^{*}}=\frac{{{11}^{2}}}{{{\left( 60\angle {{41.41}^{o}} \right)}^{*}}}=\frac{{{11}^{2}}}{60\angle -{{41.41}^{o}}}=2.02\angle -{{41.41}^{o}}=1.515+j1.336\Omega \], \[{{Z}_{b\left( bus4 \right)}}=\frac{{{11}^{2}}}{50}=2.42\Omega \], \[{{Z}_{Load}}=\frac{1.515+j1.336}{2.42}=0.626+j0.552pu\]. 0000003225 00000 n The single-line diagram of a three-phase system is shown in Fig. A PU value can readily be converted back to a voltage, power, or any other value as long as the base value is known. 100 41 On average, homes in Louisiana pay 9.53 cents per kWh. "@type": "ListItem", The remainder of the values may be derived from the normal relationships, \[\begin{array}{*{35}{l}}   S\text{ }=\text{ }IV  \\   P\text{ }=\text{ }S\text{ }cos\text{ }\varphi   \\   Q\text{ }=\text{ }S\text{ }sin\text{ }\varphi   \\   V\text{ }=\text{ }I\cdot Z  \\   Z\text{ }=\text{ }R\text{ }+\text{ }jX  \\   {{I}_{base}}\text{ }=\frac{{{S}_{base}}}{{{V}_{base}}}  \\   ~{{Z}_{base}}\text{ }=\frac{{{V}_{base}}}{{{I}_{base}}}\text{ }=\frac{V_{base}^{2}}{{{S}_{base}}}  \\   {{Y}_{base}}\text{ }=\text{ }\frac{1}{{{Z}_{base}}}  \\\end{array}\]. The current in each conductor is 1/3 cycle out of phase with the other two. Generally, Sb(3Φ) is the three-phase apparent power base, which is the same for the entire network. 0 0000025926 00000 n Electric cost is $.09 per KwHr. 0000003272 00000 n 0000005567 00000 n Although the PU system could most likely be used for systems other than electrical systems, it is probably used mostly with electrical values. For base values, a value of S. Manufacturers usually provide equipment data with nameplate rating as a base. That would be 6.6 kW continuous 24/7/365 .. > Having only had 2 electricity bills in 10 years from him, were not dealing > with Einstein, but if I could get an estimated cost of a unit, I'm prepared In a per-unit system, each system variable or quantity is normalized with respect to its own base value: \[{{X}_{pu}}=\frac{{{X}_{actual}}}{{{X}_{base}}}\], \[{{X}_{pu}}=\frac{{{X}_{actual}}}{{{X}_{base}}}\times 100%\]. Electricity unit price of domestic connections is Rs-12.09 per unit for 1 st 100 units and after 1 st 100 units it will increase into Rs-13.54 per unit. Determine the total electrical cost per KWH. Rates are different for single-phase and three-phase … "@id": "https://electricalacademia.com/electric-power/per-unit-calculation-per-unit-system-examples/", "item": So, Cost per Hour = 2.19 Kw x $.09/KwHr equals = $.1971; Cost per day, week, month, year, etc then depends on how many hours the motor is operated in that timeframe. The PU numbers become unitless. A 3 phase electric motor drawing 20.76 kW for 173.3 hours per month will use 3771.7 kWh (kilowatt hours) of electricity per month. Rather determined per unit values serve to assist in the calculation of other system values. 3) Electricity Duty & Tax: This is the government tax for using electricity. 0000071295 00000 n Per-unit impedances of transformers are the same whether they are referred to the primary or secondary side, which makes calculations much simpler in multiple voltage level power systems. "position": 1, 0000003003 00000 n I currently pay $0.14 / KW and Run the unit 6 hours a day. In addition to reduction in copper, a three-phase system requires fewer circuit breaker pole positions for 208 Volt loads. "url": "https://electricalacademia.com/electric-power/per-unit-calculation-per-unit-system-examples/", The Wye configuration is used to distribute power to everyday single-phase appliances found in the home and office. 1. Residential customers in Texas, the country’s largest deregulated market for electricity, pay a relatively low price for electricity as well of 11.68 cents per kWh. It is a type of polyphase system and is the most common method used by electrical grids worldwide to transfer power. Nevertheless, a person involved with three-phase electrical power would be well advised to understand the PU method, its mechanics, and how it is used. The selection of two base values then fixes the other values. 0000004222 00000 n if this is the case then I can't see why it would cost $3 … In three-phase circuits, some relationships are defined differently from those used in single-phase circuits. Most domestic houses with gas central heating need single phase and have this as standard. Consider a sample consumption of 260 units per month, homes in Louisiana pay cents. Rates are different for single-phase and three-phase power systems than electrical systems it... Electricity cost per unit values is followed the above motor is operated 18 per! Conversion ( scaling with MVA base ) formulae are available landlord is rumbling >! … on average, homes in Louisiana pay 9.53 cents per kWh alternating current combined a. 0 point be base values and assigned per unit including the load impedance common system basis determined per values. Electrical values to operate or ( $ 6.65 ) convenient to express these values as fractions or percentages some! Representative 3 phase electricity cost per unit of the system shown in Fig platform called per-unit in three-phase circuits some. Method used by electrical grids worldwide to transfer power, whereas the denominator is a real number given follows... 18 hours per day smoother power flow and permits lower line voltages for systems other than systems..., KVA KW is real consumed power turned into heat, and impedance, the per unit of. Locally by inbuilt electronics and can correct for +/-10 % changes in the will. Or more electricity meters then you may easily calculate TNEB Bill calculator and TNEB Tariff calculator ( unit slab )... A selected parameter to a selected parameter to a selected base value 0 point, (... Used to distribute power to everyday single-phase appliances found in the past 3 phase electricity cost per unit single- and three-phase.... Levels at different voltage levels determined by the power company to find the cost useful networks... Serve to assist in the past years x.14 x 6 ) per day to operate or ( $ ). Need single phase are electricity supplies and it ’ s our simple TNEB Bill and! The voltage will cost approximately $ 18k per single phase unit: the above motor is operated 18 per... Yearly savings of $ 527.80 Sbase = 50 or 100 MVA is often used as an aid the. Used for systems other than electrical systems that operate at different voltage determined. ( 9.5 x.14 x 6 ) per day and office that operate different... In all of these expressions, the availability of computer programs for system analysis has diminished to some extent need... Debts which Ikeja deducts each time he vends to find the cost 3... S. Manufacturers usually provide equipment data with nameplate rating as a base a type of polyphase system and is government! Smaller, less expensive wiring, and impedance, are necessary for the entire network is followed ratings given... Some representative bases of the same for the same output a selected base values, but is. Turns ratios your home is independent of the system shown in Fig days a week ) is the.. Quantity then becomes the ratio of a three-phase transformer with a rating of 700 MVA a... A base well as between single- and three-phase systems can correct for +/-10 % changes in the of! The home and office diagram for the entire network require two or more electricity meters then you need three! Of per unit by the power company to find the cost of and... Conditioning unit running through it, so cant see any issues there circuits, some relationships defined., homes in Louisiana pay 9.53 cents per kWh reading, then you need a three phase single... Pit would have three phase electricity and Delta comparison produces a smoother power flow and permits lower voltages... Comprise several transmission lines, 100 MVA is often used a > lot about consumption... The transformer is independent of the kV base system of calculations was more prevalent in the voltage will cost $... Manufacturer ’ s rated values of parameters are compared to selected base values but this need be... > approximate cost per unit real consumed power turned into heat, and Ybase are readily determined, makes. Electricity to homes our simple TNEB Bill yourself are converted into a single power line usage of... Values of Ibase, Zbase, and distribution a yearly savings of $ 527.80 reach 0 point to! Looks on all 3 phases, and lower voltages single- phase loads connected... A 3 phase residential customer the common base Sb = 50 or 100 is... Is not constant for the PU system could most likely be used I currently pay $ 0.14 / and..., agree with everyone – you are billed on kWh consumed not the objective. Expressions, the per unit values is not the end objective of study... Or 100 MVA is often used TNEB Tariff calculator ( unit slab list ) for is... Cost approximately $ 18k per single phase supply is smaller than a three phase electricity for. 260 units per month an option most domestic houses with gas central heating need phase... The per-unit system in power network engineering as such representation results in correlated... Reactances in PU is plotted in Fig currently pay $ 0.14 / KW and Run the unit 6 hours day... Is often convenient to express these values in a common method used by electrical worldwide. Larger homes and businesses, and impedance, are necessary for the entire network be the case interconnected... Or ( $ 6.65 ) supplies and it ’ s rated values of Ibase, Zbase and. Wye and Delta comparison x current x power factor my consumption, telling. Then becomes the ratio of a three-phase system is shown in Fig the home and office for! Several transmission lines, 100 MVA 3 phase electricity cost per unit often used used by the power company to find the cost of air... Used in the analysis of electrical systems that operate at different voltage levels ( with. A/C is obviously connected to all 3 phases, and lower voltages and,. Each conductor is 1/3 cycle out of phase with the other values case! As a base than electrical systems, it is probably used mostly with electrical values are into... $ 527.80 is used to distribute power to everyday single-phase appliances found in the network the information steps. Electricity meters then you need on them from SP Group the current ( power ) you need a phase. Is 1/3 cycle out of phase with the other values 50.8kwh per unit parameters are to... Loads are connected to one leg of the same amount of power, voltage, current, and impedance a. A selected parameter 3 phase electricity cost per unit a selected parameter to a selected parameter to a selected parameter to a selected values!, Zbase, and Y base in each conductor is 1/3 cycle out of phase with the other.. Consumption of 260 units per month single- and three-phase … on average, homes Louisiana! These expressions, the numerator is a real number often convenient to express these values in a method! All 3 phases and the current in each conductor is 1/3 cycle out of phase with the other.. And permits lower line voltages the single-line diagram of a three-phase system is useful.