Electrical Transmission System Analysis EE 456 project. Team Members Abdulaziz Almarzouqi Hamzah Abeer

Transcription

1 Electrical Transmission System Analysis EE 456 project Team Members Abdulaziz Almarzouqi Hamzah Abeer Due December 14, 2012

2 Changes: MW Wind added 2. N-1 Contingency limits changed to Generator Contingency 4. Transformer Contingency 5. Updated solution o 32 Mvar CAP at bus 13 o 10 Mvar CAP at bus 5 o 10 Mvar CAP at bus 10 o New transmission from 1 to 5 o New transformer from 19 to Updated Cost Analysis 7. Cost of Electricity( Extra Credit) 2

3 8. Table of Contents Executive Summary... 4 Bas Case System... 5 System Description... 5 Lines... 5 Loads... 6 Generators... 6 Transformer... 6 System map... 7 System Outlook... 7 System Description... 7 Non-Emergency-Voltage and Current Violations... 8 N-1- Voltage and Current Violations Generator Contingency Transformer Contingency Solution Cost Analysis Government Incentives Capital Costs Running Cost Transmission Line and Capacitor Cost Overall Cost of Electricity Constraints Conclusion Appendix References

4 Executive Summary For the sake of simplicity, we have named our project Ames power system and we are assuming that the beautiful city of Ames comprise of 15 bus transmission system. In 2012, the total real power demand is 585MW and both the generators at bus 2 and 3 are operating at max 490MW, this gives -355MW at the swing bus. Generating more power than required may overheat the transmission wire and consequently damaging the system. As the excess power is not being consumed, the wastage will also reduce the overall profit margin. So to eliminate this wastage of power and for bus 1 (swing bus) to be zero, generators at bus 2 and bus 3 should operate at 299MW and 298 MW, respectively. In 2030, the real power demand increases by around 130MW. This calls for induction of more power generation capacity into the system. In our project, we have added 120.6MW Natural Gas Combined Cycle power plant and 134MW of Wind to the system in MW of Natural gas fired power plant has been installed at bus2 and Wind is added to bus 3, To fix the contingencies we have added a 32Mvar capacitor at bus Mvar Cap have been added at bus 5 and 10. A new transmission line of length 36.7 has been added from bus 1 to bus 5 to maintain the voltage level in urban area. A new transmission line of length 10.7miles has been added to induct a new transformer at bus 10. This will maintain voltage level at 69KV lines. Also, the new transformer was added because previously when one of the transformer were taken offline all the load was put on the other one causing the thermal limits to exceed the limits. As the project is being down in 2012 all the cost analysis is in current dollar value. Though, the calculated cost values might differ from other online sources because of availability of several different kinds of Natural gas power plant and transmission lines. At the end of the project, we have also calculated the amount of dollar it will require to execute the very same project in

5 1. Base Case System 1.1. System Description Ames Power System is a 15 bus transmission system and specifications of this system are as follows: Lines Conductor Ampacity The system is currently using three types of conductors, Dove, Drake, and Hawk.[1] The ampacities of these conductors are listed below( Ampacity Chart is attached at the end). o Dove: 726 A o Drake: 907 A o Hawk: 659 A Voltages All most all of the lines operate on 161kv lines except 16 and 17. 5

6 Table 1: Existing line data Loads Load data for 2012 and MW MVAR MW MVAR 'LARK' 'LARK' 'JAY' 'JAY' 'RAVEN' 'RAVEN' WREN WREN 'ROBIN' 'ROBIN' 'SISKIN' 'SISKIN' 'JUNCO' 'JUNCO' 'QUAIL' 'QUAIL' 'HERON' 'HERON' 'EGRET' 'EGRET' 'GULL' 'GULL' 'CROW' 'CROW' Total Total Total Increase from 2012 to Difference MW MVAR Increase in MW 6

7 Increase in MVAR Generators Buses 1-3 are generation buses. Bus 1 is assumed to be the swing bus. Each generator is rated at 490 MW with a minimum volt-amperes reactive limit of -100 Mvar and a maximum volt-ampere reactive limit of 250 Mvar Transformers Ames Power System contains two 69kV-161kV transformers located at the Siskin and Crow buses. It is assumed that these transformers are rated at 60 MVA in open air System Map The following shows the one line diagram of the Ames Power System. 7

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9 2. System Outlook 2.1 System Description Ames will experience 1.1% load growth tell All the load calculations are in section To supply power to this increased load we are going to install 120.6MW Natural gas power plant at bus 2 and 130MW of Wind farm at bus (10% and 90% Capacity Credit) Voltage and Current Violations Non-Emergency Violations Under normal conditions, per unit voltage magnitudes at all buses should be higher than.95 pu. Also, lines, transformers, and generators must operate within their specified limits. Voltage Violations o Multiple buses were found to have voltage violations. Table 8 shows these violations. Current Violations: o No current violation Thermal Violation: o None Transformer Contingency: o Removing transformer from line causes thermal Violation at line and the following voltage violations 9

10 Wind Farm (134 MW) NEW GAS (120.6MW) N-1 Emergency Violations Under N-1 emergency conditions, per unit voltage magnitudes at all buses should be higher than.95 pu and lower than 1.05 times the normal ratings. Voltage Violations Multiple buses were found to have voltage violations. Shown in table below. 10

11 Voltage violations for N-1 emergency conditions Generator Contingency: Wind Farm Offline: No thermal voilation 11

12 New Gas Offline: No thermal voilation Bus 2 Gen offline: No thermal Voilation Bus 3 Gen Offline Line 2 to 12 close to 100% 12

13 Transformers Contingency: Removing either of the transformers causes extra load on the opposite side of the transmission line. Recommend adding new transformer from 7 to Solutions Solutions to the violations must be developed. To do this in the most cost effective way, capacitors will be added at the buses with the most voltage violations. Placing the capacitors at these buses will decrease the voltage drop and bring the buses within the acceptable limit. We have added a 32Mvar capacitor at bus Mvar Cap have been added at bus 5 and 10. A new transmission line of length 36.7 has been added from bus 1 to bus 5 to maintain the voltage level in urban area. A new transmission line of length 10.7miles has been added to induct a new transformer at bus 10. This will maintain voltage level at 69KV lines. Also, the new transformer was added because previously when one of the transformer were taken offline all the load was put on the other one causing the thermal limits to exceed the limits. 13

14 32 Mvar CAP at bus Mvar CAP at bus 5 10 Mvar CAP at bus 10 New transmission from 1 to 5 New transformer from 19 to 10 The updated one line diagram for the Ames Power System with solution 14

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17 Cost Analysis: Following factors were considered while calculating the overall cost required for building a gas fired power plant: 1) Government Incentives 2) Capital cost( Capacity, Constructions, labor, Air emissions controls for coal and natural gas plants, financing) 3) Fuel Cost ( Running Costs) 4) Transmission Line and Capacitor Cost 5) Overall cost of Electricity 4.1. Government Incentives: Loans: Federal government provides loans through Department of Energy for carbon-control technologies that cover up to 80% of the cost of a project. [2]. Energy Investment Tax Credit: Tax credit is available for entities willing to invest in energy production. Only wind energy doesn t qualify for these tax credits Capital Cost: All the generating technologies are capital intensive, meaning they require a large amount of invest at the start. Natural gas fired plant cost $1200 per KW overnight cost, much less than its competitors nuclear, coal that cost around $3000 per KW on average. Construction Cost for power plants have escalated immensely during the last one decade. There has been 108% and 92% increase in capital cost for wind and gas, respectively. Predicting the future cost (2030) of setting up a power plant accurately is very important. This will give a clear comparison between gas and other generating options. We are assuming that we are going to start building the 135 MW gas power plant in Adding this much MWs will make the system good till

18 Table 1: Cost of building a NG power plant, all value are in current(2012) dollar value 4.3. Fuel Cost ( Running Costs) Cost of operation has been included in this section of the report. Table 2 show all the running (variable and fixed) costs for a simple NG plant and one with carbon control. Uncertainty of fuel cost and operation variable will be studied in next section. Table 2: Total cost of operation/year (2012) Future prediction (2030): Though it s very difficult to predict future value of a fossil fuel, considering the following factors remains constant and inflation remains constant at an average of 2.5% the capital and operation costs for setting up a NG power plant in 2030 are shown in table 4. 18

19 Table 3: Financial Assumption [[3] page 59] Table 4: Future values of capital and Running costs 4.4. Transmission Line and Capacitor Cost: All the costs values for this part is from the book. 19

20 4.5. Overall Cost of Electricity: Assuming the life of the plant to be 30 years, the cost of KWH electricity is as follows. Table 5: Cost of Electricty($/MWH) 5. Constraints: Coal is being used as a primary method to produce electricity. However, the new federal and state polices are incenting or promoting the use of natural gas to generate electricity. The following downsides of natural gas as a fuel for producing electricity are not consistent with economic policy and sound energy [4]. 1. Natural gas is more expensive fuel than coal and wind is a very close competitor. 2. Natural gas prices are highly volatile, whereas coal prices are more stable. 3. Though, North America is considered to be natural gas rich continent, there is still significant uncertainty about the amount of natural gas available at low prices. 4. The cost of developing future natural resources is expected to be much higher than current price because of the increasing labor and capital cost. 5. Using natural gas for electric power generation is going to increase the price for other sectors of industry. That will affect the economy negatively 6. Setting a natural gas plant in Ames will require significant infrastructure investment. Supporting Data: According to data from the U.S Energy Information Administration (EIA), the average cost of natural gas used in electricity generation was approximately 260 percent more expensive thab coal during the period

21 Table 6: Natural Gas VS Coal As said earlier, the price of Natural gas is much more volatile than coal. The following graph compares monthly price of natural gas and coal Table 7: Mothly price comparison 6. Conclusion The Ames Power System will now be able to support additional load until To avoid any voltage violations, a 32Mvar capacitor has been added to the system. To avoid any current violations a new generator is separately added at bus 9 instead to increasing the capacity of old generators or adding the new one at the same lines. 21

22 Appendix Ampacity Chart 22

23 References [1] A.R.Bergen, Power System Analysis: Transmission line modeling, Table D4.1.2, page 123 [2] S.Kaplan, Power plants: Characteristics and Costs, November 2008, pages 16, 17 Appendix B [3] U.S Department of Energy, Role of Alternative Energy Sources: natural gas Technology Assessment June 2012 [4] American Coalition for Clean Coal Electricity. Displacement of Coal with Natural gas to Generate Electricity, August 2012 [5] U.S Energy Information Administration, U.S. Crude Oil, Natural Gas, and NG Liquids Proved Reserves, August