POWER Upgrading of transmission line by combining ac-dc transmission guide : pro. J.b.survaiya

POWER Upgrading of transmission line by combining ac-dc transmission

by h . gadhiya, h . bharadva, s . senta, n . ghinaiya guide : pro. J.b.sArvaiyaProject themeIntroductionBackground surveyTheoretical proof of ac-dc combine transmissionMatlab simulation of ac-dc combine transmissionResponse of ehv ac transmissionResponse of ac-dc combine transmissionCase of studyEconomical proof of ac-dc combine transmissionAdvantages & Limitation of ac-dc combine transmissionConclusion

1. introduction1). EHV AC Transmission2). HVDC Transmission3). AC-DC Combine Transmission a). AC-DC 3-phase Single Line Transmission b). AC-DC 3-phase Double Line Transmission

Condition of transmission2. Matlab simulation

3.Case of studySIMULTANEOUS AC-DC POWER TRANSMISSION SYSTEM:Sending End AC Voltage (VS) = 400 kvReceiving End AC Voltage (VR)= 392.6 kV AC Current (Iac)= 2.341 kA Sending End AC Power (PS)= 1600 MW Receiving End AC Power (PR)= 1100 MW Total Reactance per phase per circuit (X)= 93.82 Rectifier Voltage (Vdr)= 440 kV Inverter Voltage (Vdi)= 300 kV DC Link Current (Id)= 1.74 kA Sending End DC Power= 765.6 MW Receiving End DC Power= 522 MW = 70Total Power Transmitted = 21600 + 765.6 = 3965.6 MWTotal Power Received= 2722 MW Transmission Loss= 3965.6 MW 2722 MW= 1243.6MWNow, dc voltage across one winding = 440/2 = 220 kV.Induced voltage across secondary winding of transformer= 200 kVVdo= 220 kVSo, power factor of the rectifier (cosr)= 220/271 = 0.812Similarly for inverter Vdoi = 271 kVVdo = 150 kVPower factor of the inverter (cosi)= 150/271 = 0.5535So, reactive power drawn by the rectifier = 765.6 tanr = 550.3 MVARReactive power drawn by the inverter = 522 tani = 785.45 MVARPower Up gradation =Power transformer in composite AC DC transmissions - power transmitted in pure transmission / power transmitted in pure transmission= [ 2722 2250 / 2250 ] 100= 21 %4.Economy Economy of the system

[1] Economy of system based on comparison

[2] economy of system based on structure FOR DOUBLE CIRCUIT EHV LINEBase cost of 500 KV double circuit transmission lineRs. 1,78,020,000 Line Multiplier :Conductor ACSR (1.0) ACSS (1.08) TLS (3.60)Tower Structure: Lattice (1.0) Tabular Steel (1.50)Transmission Length: Up to 4.82 Km (1.50) 4.82 Km to 16.093 Km (1.20) Above 16.093 Km (1.0) Total transmission line cost = [ (base transmission cost)*(conductor multiplier)*(structure multiplier) *(1.6093)*(no of kilometer) ] Total transmission line costRs. 5.696641010SUB-STATION CAPITAL COSTBase cost of Sub-Station (500 KV)Rs. 148,320,000LINE & TRANSFORMER POSITION COST & MULTIPLIER (500 KV)Cost multiplier : Breaker & half multiplier (1.50) Ring bus multiplier (1.0) Cost per line / transformer positionRs. 173,040,000Transformer cost (Rs. per MVA)230 / 500 KV Transformer Rs. 660,000 115 / 500 KV Transformer Rs. 600,000 Transformer cost (Rs. Per MVA)Rs. 600,000REACTIVE COMPONENTS COST PER MVARShunt reactorRs. 1,200,000Series reactorRs. 600,000SVC capital costRs. 5,100,000Total substation cost = [ (sub-station base cost)+(line per transformer position base cost)*(no. of line per transformer position)*(CRB or BAAH multiplier)+(transformer cost per MVA)*(transformer MVA rating)+(SVC cost per MVAR)*(require MVARs)+(series capacitor cost per MVAR)*(require MVARs)+(shunt reactor cost per MVAR)*(require MVARs) ]Total substation costRs. 839,052,000 x 2 = 1,678,104,000TOTAL COSTTotal costRs. 5.86445041010

HVDC TRANSMISSION LINE500 KV HVDC bidirectional pole line (per Km)Rs. 89,040,000TOTAL COST OF TRANSMISSION LINETotal cost of transmission lineRs. 2.84928X1010SUB-STATION CAPITAL COSTConverter terminal (include DC switching station equipment)Rs. 3,850,000,000Reactive support (synchronous condensers, SVCs, etc)Rs. 2,100,000,000AC switch yardRs. 280,000,000COST OF SUB-STATIONCost of sub-stationRs. 6,230,000,000 x 2 = 1.246 x 1010TOTAL COSTTotal costRs. 3.47228 x 1010COMBINE HVDC-HVACSUB-STATION COSTSub-Station costRs. 6,230,000,000 x 2 = 1.246 x 1010COST OF ZIG-ZAG TRANSFORMER (125)Cost of zig-zag transformer per MVA (Rs. Per MVA)Rs. 78,000Cost of 4 zig-zag transformer (Rs. Per MVA)Rs. 78,000 x 4 = 312,000Total cost of four zig-zag transformerRs. 390,000,000TOTAL COSTTotal costRs. 1.285 x 10105.conclusionADVANTAGES OF SYSTEM

(1) The feasibility to convert ac transmission line to a composite acdc line has been demonstrated. (2) For the particular system studied, there is substantial increase (about 21.45%) in the load ability of the line. (3) The line is loaded to its thermal limit with the superimposed dc current. (4) The dc power flow does not impose any stability problem.(5) Dc current regulator may modulate ac power flow. (6) There is no need for any modification in the size of conductors, insulator strings, and towers structure of the original line. (7) The optimum values of ac and dc voltage components of the converted composite line are and 1/2 times the ac voltage before conversion, respectively.

limitation

(1) There Is Certain Limit Of Power Upgrading Of Transmission Line, So We Can Not Apply This Basic Scheme Where New Unit Has More Power Capacity Then Limit Of Power Upgrading Of Transmission Line. (2) The Combine HVDC-HVAC Transmission Line Is Very Complicated. (3) There Is Necessity Of Double Circuit Long Extra High Voltage AC Transmission Line In Running Power Generating Station. (4) We Cannot Transfer The Power By This Basic Scheme Where Double Circuit EHV Line Not Going From The Power Generating Station. Application

(1) addition of generation unit

(2) solar generation unit

conclusionFor the particular system under study, the power up gradation of the line is observed to be twenty one percent with the simultaneous ac-dc power flow. Maximum power up gradation is obtained at a transmission angle of 60. The line is loaded to its thermal limit with the superimposed dc current. The dc power flows independent of the ac power in the transmission line.References

papers:-

[1] Upgradation Of Power Flow In EHV AC Transmission International Journal Of Scientific Engineering And Technology By K.K.Vasishta Kumar, K.Sathish Kumar.[2] Power Upgrading Of Transmission Line By Combining AC-DC Transmission, Swarnandhra College Of Engineering Technology Narsapur By Jarupula Somlal.[3] Power System Stability Enhancement By Simultaneous AC-DC Power Transmission International Journal Of Advanced Research In Electrical, Electronics And Instrumentation Engineering Vol. 2, Issue 5, May 2013 By Abhishek Chaturvedi, V. K. Tripathi, T Vijay Muni, Neeraj Singh.[4] Power Tapping Of Upgrade Transmission Line By Using Composite Ac-dc Power Transmission Lines International Journal Of Engineering Research And Development By CH.Veeraiah, Y.Rambabu, V.K.R.Mohan Rao.

BOOKS:-

[1] D P Kothari And I J Nagrath MODERN POWER SYSTEM ANALYSIS FNAE Fnasc, Fellow-ieee Director General, Raisoni Group Of Institutions, Nagpur.[2] Tim Mason- Project Manager, Trevor Curry And Dan Wilson, CAPITAL COSTS FOR TRANSMISSION AND SUBSTATION Western Electricity Coordinating Council.[3] Roberto Rudervall, J.P. Charpentier And Raghuveer Sharma, HIGH VOLTAGE DIRECT CURRENT (HVDC)TRANSMISSION SYSTEMS Technology Review Paper, Presented At Energy Week 2000, Washington, D.C, USA, March 7-8, 2000.Thank you