Chapter 12 Load Flow Study DPR Final

Chapter 12 Load Flow Study

ITECO-CEMAT-ICGS JV Page 12-i

Table of Contents

12. LOAD FLOW STUDY......................................................................... 12-1 12.1 Introduction................................................................................................... 12-1 12.2 Methodology .................................................................................................. 12-1 12.3 Result.............................................................................................................. 12-2

12.3.1 Detail Result........................................................................................ 12-2 12.3.2 Summary of Result ............................................................................. 12-6 12.3.3 Conclusion .......................................................................................... 12-6 12.3.4 Limitation of Load Flow Study........................................................... 12-6

List of Tables Table 12.1: New Power Plants Expected to be Completed by the Year 2013..................... 12-2 Table 12.2: New Capacitor Banks to be Constructed by the Year 2013 ............................. 12-2 List of Figures Figure 12.1: Load Flow Analysis of INPS Nepal for 2013 ................................................. 12-7

LIKHU 1 HYDROELECTRIC PROJECT DETAILED PROJECT REPORT CHAPTER 12: LOAD FLOW STUDY

ITECO-CEMAT-ICGS JV Page 12-1

12. LOAD FLOW STUDY

12.1 Introduction This section presents an approximate performance analysis of Likhu 1 HEP after its inclusion into the Integrated Nepal Power System (INPS) in its expected commissioning year, which is 2012/13 AD. The purpose of this study is to identify the impact of inclusion of this HEP to the INPS system such as verification of acceptable voltage and power angle profile and losses in transmission lines. Likewise, such analysis helps in identifying points in the system requiring reinforcement if the overall result is not within the desired limits. Likhu 1 HEP is a run-of-river type plant expected to generate a maximum of 77 MW of power envisaged mainly for export to India. The power generated by this project, along with upcoming Likhu 2 and Likhu A HEPs downstream, is likely to be evacuated using partly a single circuit and partly a common 220 kV double circuit transmission line to the new NEA 220 kV Kirnetar substation via a common node at Likhu 2 switchyard. The new Kirnetar switchyard will then transfer the power to Dhalkebar 220 kV grid substation from where the power is exported to Muzaffarpur substation (India). The load flow simulation is performed with the above concept and the scenario is to be expected after the completion of all three mentioned projects. The power from Likhu 1 HEP is expected to be evacuated using a single circuit 220 kV transmission line if constructed ahead of Likhu 2 and Likhu A projects, with due provision for adjusting to the above mentioned scenario.

12.2 Methodology The load flow study results presented here are derived from computer simulation of INPS for the said year. The simulation software used in this project is free software of Power System Analysis Tool (PSAT), a MATLAB toolbox for static and dynamic analysis of electrical power system. All necessary assumptions made here about the changes in the INPS are in accordance with the NEA Annual Report, 2009. Some of the significant assumptions made for the load flow simulation are as below:

All power plants generate at full capacity. All loads are connected to the system. The load at different substations are those

expected in the year 2012/13 by projection from the recorded load demand of 2009 incorporating yearly demand forecast as stated in NEA Annual Report, 2009.

Some of the power plants and loads operating at 33 kV lines are assumed to be operating at 66 kV or 132 kV level.

Marsyangdi HEP (69 MW) is considered as the swing/reference bus due to its central location in the INPS.

A total of 65 MW is imported from India via Khusaha (50 MW) and Tanakpur (15 MW) substations.

Khimti Dhalkebar 220 kV line and substations are assumed to be in operation by 2013. Likewise, Khimti-Matatirtha 220 kV line and Chandranigahapur 132 kV line and substations are also assumed to be commissioned by then.

The power equivalent to the sum of generation from Likhu 1, Likhu 2, Likhu A, Likhu IV, Kirne HEPs, which converge at NEA new 220 kV Kirnetar substation and Balephi HEP which converge at NEA 132 kV Lamosamghu substation, is exported to



India from Dhalkebar 220 kV substation after flowing through KhimtiDhalkebar 220 kV transmission line.

The new power plants expected to be completed by the year 2013 are as follows:

Table 12.1: New Power Plants Expected to be Completed by the Year 2013

S.N. Name of HEP Operating Voltage in kV

Additional power produced in

the year 2012/13 in MW Remarks

1 Chamelia 132 30 For use in Nepal 2 Kulekhani 3 132 14 For use in Nepal 3 Upper- Tamakoshi 220 456 For use in Nepal 4 Likhu 1 220 77 For export to India 5 Likhu 2 220 50 For export to India 6 Likhu A 220 60 For export to India 7 Likhu IV 220 120 For export to India 8 Balephi 132 50 For export to India 9 Kirne 132 68 For export to India

Total Additional Power (MW) 925

Likewise, the new capacitor banks and assumed to be constructed by the year 2013 and shown as operating in either 66kV or 132kV in the simulation are as follows.

Table 12.2: New Capacitor Banks to be Constructed by the Year 2013

S.N Load Center No. of units Per unit Capacity (MVar) Total Capacity

(MVar) 1 Bharatpur 2 12.5 25 2 Dhalkebar 2 12.5 25 3 Butwal 2 20 40 4 Simra 3 5 15 5 Hetauda 2 5 10 6 Siuchatar 2 10 20 7 Patan 2 10 20 8 New-Baneshwor 2 12.5 25 9 Balaju 2 12.5 25

10 Chabel 2 12.5 25 Total Additional Reactive Power (MVar) 230

12.3 Result

12.3.1 Detail Result The result of the load flow simulation as generated by PSAT is presented below.

NETWORK STATISTICS Buses: 70 Lines: 100 Transformers: 15 Generators: 30 Loads: 43



SOLUTION STATISTICS Number of Iterations: 4 Maximum P mismatch [MW] 0 Maximum Q mismatch [MVar] 0 POWER FLOW RESULTS BusVphase Pgen Qgen PloadQload [kV][deg] [MW] [MVar] [MW][MVar] Amlekhgunj 64.5083 -2.6655 0 0 1.2 0.9 Anarmani 125.4479 -3.1981 0 0 42.2 31.6 Atariya 133.848 -0.85044 30 7.267 17.5 2.8 Balaju 64.915 -0.65456 0 0 41.97 6.48 Balaju1 130.9612 -0.42941 0 0 0 0 Balephi 134.64 9.588 50 11.4714 0 0 Banepa 65.1963 2.9811 0 0 0 0 Baneswor 64.5833 0.64448 0 0 37.4 3 Bhakatapur 64.3989 1.3785 0 0 24.8 18.6 Bhaktapur1 128.8505 1.4533 0 0 57.2 38.4 Bharatpur 133.2066 -0.50578 0 0 48.8 11.6 Bharatpur1 222.1459 -0.51452 0 0 0 0 BhoteKoshi 133.914 8.8903 36 8.5777 0 0 Birgunj 61.9571 -5.9702 0 0 60.4 9.2 Butwal 136.3032 0.33019 5.1 19.4176 63 7.3 Chandranig 129.7456 5.1874 0 0 21.6 16.2 Chatara 133.7847 -0.00744 3.2 1.8 0 0 Chilime 66.726 5.2171 20 -1.6773 5.5 4.1 Damauli 135.5304 0.54784 0 0 17.5 13.1 Devighat 66.066 1.212 14 4.3006 3.8 2.9 Dhalkebar 129.9793 9.9727 0 0 52.9 14.6 Dhalkebar- 216.5475 11.5579 0 0 400 290 Duhabi 133.7109 -0.02971 0 0 94.1 28.4 Dumkibas/B 135.6649 0.19463 0 0 6.1 4.9 Gandak 136.092 0.43338 15 4.8004 0 0 Harisidhi 129.2518 0.79806 0 0 0 0 Hetauda 132.6925 -0.33897 0 0 48.8 26.6 Hetauda1 221.3554 -0.35924 0 0 0 0 Hetauda66 66.132 -0.70246 14.41 -0.19113 16.1 12.1 Ilam 127.116 -2.69 6 3.5701 0 0 Jhimruk 134.904 -1.1702 12 0.97718 0 0 KaliGandak 138.072 3.5083 144 -8.3749 0 0 Kawasoti 134.6472 -0.12823 0 0 8.2 6.2 Khimti-132 136.422 15.2764 60 13.3941 0 0 Khimti-220 227.3458 15.2785 0 0 0 0 Kirne 137.214 17.5735 68 -7.7848 0 0 Kohalpur 129.7034 -3.2131 0 0 21.8 16.41 Kulekhani- 133.32 0.6451 32 17.914 0 0 Kulekhani- 133.452 0.43725 14 10.3697 0 0 Kulekhani1 67.2342 0.23031 60 39.836 6.6 5 Kushaha 135.8544 1.4921 50 77.6616 0 0 Lahan 129.5927 6.2261 0 0 36.7 27.5 Lamahi 133.0018 -1.9618 0 0 11.2 0.4 Lamosanghu 132.6331 7.9812 0 0 3.3 2.5 Lekhnath 137.0319 1.3227 0 0 7.6 5.7 Likhu 1 229.009 16.2892 77 0.55404 0 0 Likhu 2 228.8 16.0505 50 -7.7138 5.5 3.662 Likhu IV 228.47 15.5703 120 52.7789 6 4 Likhu A 229.02 16.198 60 8.8288 0 0 Lumki 131.4416 -2.2944 0 0 7.1 5.3 MMars 138.336 1.7955 70 17.5599 0 0 Mahendrana 133.782 -0.61028 15 3.8033 10.4 7.8 Marsyangdi 135.4716 0 -15.2732 39.9258 0 0 Matatirtha 130.6149 0.40633 0 0 0 0 Matatirtha 217.8078 0.45878 0 0 0 0 Modi 138.138 2.4144 14.8 7.4353 4.1 3.1 Multifuel 134.1196 0.06938 31.2 23.4 0 0 New Parwan 126.11 -4.5015 0 0 16.7 12.5 NewChabel 63.9558 -1.1492 0 0 41.4 2.2 Panchkhal 65.736 3.939 7.5 -3.0363 0 0 Parwanipur 63.0233 -4.5592 0 0 0 0 Patan/teku 64.449 0.03207 0 0 38.9 9.2 Pokhara 137.148 1.1784 2.5 39.5642 42.2 31.6 Shivpur/Ch 133.767 -1.2448 0 0 11.2 8.4 Simra 63.5667 -3.9171 0 0 21.1 0.8



Siuchatar 64.8023 -0.3426 0 0 27.9 18.2 Siuchatar1 130.1074 -0.34825 0 0 103 45 Sunkoshi1 66.528 4.902 10 -0.36382 0 0 Tamakoshi 230.098 15.5398 456 146.4585 0 0 Trishuli1 66.528 1.9303 24 8.1547 5.3 4 LINEFLOWS

FromBusToBusLine PFlow QFlow PLossQLoss [MW] [MVar] [MW][MVar] Devighat NewChabel 1 13.0866 1.4952 0.36113 0.18928 Chilime Trishuli1 2 14.5 -5.7773 0.38225 0.28677 Lumki Kohalpur 3 9.8457 2.5854 0.05923 -3.6896 Mahendranag Atariya 4 4.6 -3.9967 0.00552 -4.2803 Atariya Lumki 5 17.0945 4.7506 0.14876 -3.1348 Kawasoti Bharatpur 6 7.9572 5.5524 0.04097 -2.3459 Damauli Bharatpur 7 24.0474 8.0376 0.25366 -1.3029 Lekhnath Damauli 8 17.4624 4.1238 0.12459 -1.6575 Modi Pokhara 9 28.3049 0.85193 0.1695 -1.3873 KaliGandaki Lekhnath 10 36.97 -1.8571 0.32675 -1.1616 KaliGandaki Butwal 11 44.6728 -0.3984 0.57677 -0.61057 Balaju1 Siuchatar1 12 0.80919 45.671 0.06975 0.01007 Marsyangdi Siuchatar1 13 7.8224 17.644 0.19437 -3.291 Hetauda66 Amlekhgunj 14 26.5359 5.2939 0.48635 0.81853 Amlekhgunj Simra 15 25.4496 4.0254 0.28945 0.48601 Lamahi Shivpur/Ch 16 -11.4816 -3.1067 0.04231 -2.4439 Hetauda Bharatpur 17 3.2607 -24.8667 0.02276 -25.5685 Hetauda Bharatpur 18 3.2607 -24.8667 0.02276 -25.5685 Hetauda66 Amlekhgunj 19 26.5359 5.2939 0.48635 0.81853 Amlekhgunj Simra 20 25.4496 4.0254 0.28945 0.48601 Simra Parwanipur 21 14.6101 3.1394 0.09032 0.08221 Simra Parwanipur 22 14.6101 3.1394 0.09032 0.08221 Parwanipur Birgunj 23 30.5965 5.3284 0.39649 0.72841 Parwanipur Birgunj 24 30.5965 5.3284 0.39649 0.72841 Dhalkebar Chandranig 25 33.5126 -9.3362 0.75284 -2.0756 New Parwani Hetauda 26 -48.865 -17.0772 1.2298 1.212 Kulekhani1 Siuchatar 27 8.962 10.3556 0.2229 0.09118 Lahan Dhalkebar 28 -43.1044 9.7467 0.76953 -0.07885 Duhabi Kushaha 29 -48.4778 -13.5566 0.41261 0.10525 Duhabi Kushaha 30 -48.4778 -13.5566 0.41261 0.10525 Anarmani Duhabi 31 -36.2327 -24.7572 0.96777 0.03942 Khimti-132 Lamosanghu 32 127.2896 0.59615 4.3135 13.4158 BhoteKoshi Lamosanghu 33 36 8.5777 0.20144 -0.93264 Siuchatar Patan/teku 34 -12.248 18.0574 0.05057 0.12781 Bhaktapur13 Lamosanghu 35 -99.39 6.3629 3.1331 9.1008 Bhaktapur13 Lamosanghu 36 -99.39 6.3629 3.1331 9.1008 Siuchatar Patan/teku 37 -10.4251 18.763 0.06513 0.12173 Kohalpur Lamahi 38 -12.0135 -10.1351 0.1274 -4.2778 Balaju NewChabel 39 6.1365 3.1571 0.06302 -0.1366 Bhakatapur NewChabel 40 8.4507 -3.0068 0.18679 -0.16015 Bhakatapur NewChabel 41 8.4507 -3.0068 0.18679 -0.16015 Balaju NewChabel 42 6.1365 3.1571 0.06302 -0.1366 Trishuli1 Balaju 43 14.9546 -0.75579 0.40261 0.28563 Trishuli1 Balaju 44 14.9546 -0.75579 0.40261 0.28563 Bhakatapur Baneswor 45 8.1717 -8.5097 0.08578 -0.00138 Bhakatapur Baneswor 46 8.1717 -8.5097 0.08578 -0.00138 Dumkibas/Ba Kawasoti 47 16.2152 10.9225 0.05798 -0.82986 Khimti-220 Tamakoshi 48 -225.627 -82.8727 2.373 -9.6435 Kulekhani1 Siuchatar 49 8.962 10.3556 0.2229 0.09118 Hetauda66 Kulekhani1 50 -14.281 -5.1687 0.15228 0.10774 Kulekhani-3 Hetauda 51 31.5492 0.13731 0.18013 0.3599 Kulekhani-2 Matatirtha 52 14.4305 28.4828 0.176 0.33862 MMars Marsyangdi 53 34.632 5.8361 0.51994 -1.0074 Damauli MMars 54 -34.8939 -10.8535 0.47404 0.87037 Khimti-220 Dhalkebar- 55 340.6846 127.0957 7.9473 -4.5917 Hetauda66 Kulekhani1 56 -20.838 -8.5099 0.20484 0.33839 Duhabi Chatara 57 -3.199 -2.1344 0.001 -0.33441 Multifuel Duhabi 58 15.6 11.7 0.0271 -0.2745 Marsyangdi Bharatpur 59 21.6533 24.6456 0.14334 -0.65815 Shivpur/Cha Butwal 60 -22.7239 -9.0629 0.21205 -2.4102 Dhalkebar Chandranig 61 90.5795 -19.5854 2.0344 5.657 Chandraniga Hetauda 62 99.7049 -48.7031 2.9184 8.854 Khimti-220 Dhalkebar- 63 340.6846 127.0957 7.9473 -4.5917 Kulekhani-2 Kulekhani- 64 17.5695 -10.5689 0.02035 -0.33649 Matatirtha1 Khimti-220 65 -64.279 -13.4772 0.69557 -11.8842 Pokhara Lekhnath 66 -11.5646 10.2034 0.01629 -0.31587



Hetauda1 Bharatpur1 67 1.5363 -31.1741 0.00976 -51.3032 Banepa Bhakatapur 68 17.177 -3.4355 0.30875 0.22621 Modi KaliGandak 69 -17.6049 3.4833 0.07944 -2.2377 Damauli Marsyangdi 70 10.6843 -4.5028 0.04757 -0.02331 Butwal Dumkibas/B 71 3.6781 2.9446 0.0076 -2.2497

FromBusToBusLine PFlow QFlow PLossQLoss [MW] [MVar] [MW][MVar] Likhu 2 Khimti-220 72 91.1993 -0.2883 0.50961 -10.9291 Hetauda1 Bharatpur1 73 1.5363 -31.1741 0.00976 -51.3032 Jhimruk Lamahi 74 12 0.97718 0.14067 -2.1733 Ilam Anarmani 75 6 3.5701 0.03268 -3.2726 Khimti-220 Likhu-4 76 -56.8641 -32.4802 0.13589 -8.0908 Kushaha Lahan 77 -47.7809 50.3379 1.7279 3.3445 Harisidhi Matatirtha 78 16.714 -43.5292 0.11026 -3.7218 Harisidhi Bhaktapur1 79 -100.1224 50.1337 0.2632 -0.27426 Likhu-2 Khimti-220 80 91.1993 -0.2883 0.50961 -10.9291 Khimti-220 Likhu-4 81 -56.8641 -32.4802 0.13589 -8.0908 Balaju1 Bharatpur 82 -13.6104 -71.8614 0.33044 0.7188 Lahan Dhalkebar 83 -43.1044 9.7467 0.76953 -0.07885 Khimti-220 Tamakoshi 84 -225.627 -82.8727 2.373 -9.6435 Khimti-132 Kirne 85 -67.272 9.0007 0.72803 1.2159 Siuchatar Balaju 86 6.1926 -5.5612 0.01942 -0.04266 Multifuel Duhabi 87 15.6 11.7 0.0271 -0.2745 Butwal Dumkibas/B 88 3.6781 2.9446 0.0076 -2.2497 Gandak Dumkibas/B 89 15 4.8004 0.02578 -0.63354 Likhu 1 Likhu-2 90 77 0.55404 0.06739 -0.71357 KaliGandaki Butwal 91 44.6728 -0.3984 0.57677 -0.61057 Lamosanghu Balephi 92 -49.5716 -11.2851 0.42843 0.18633 Matatirtha Siuchatar1 93 95.1152 1.7481 0.3458 -0.11582 Siuchatar Balaju 94 6.1926 -5.5612 0.01942 -0.04266 Likhu-2 Likhu-A 95 -59.966 -9.5316 0.03401 -0.70286 Baneswor Patan/teku 96 31.0397 -13.4289 0.20931 0.26518 Baneswor Patan/teku 97 31.0676 -13.4114 0.20918 0.26551 Sunkoshi1 Panchkhal 98 10 -0.36382 0.12429 -0.09778 Panchkhal Banepa 99 17.3757 -3.3023 0.19874 0.13316 Devighat Trishuli1 100 -2.8866 -0.09459 0.02207 -0.49244 Hetauda Hetauda66 101 19.6475 9.355 0.00469 0.15464 Hetauda1 Hetauda 102 -1.5363 31.1741 0.00962 0.02887 Matatirtha1 Matatirtha 103 32.1395 6.7386 0.011 0.03301 Hetauda1 Hetauda 104 -1.5363 31.1741 0.00962 0.02887 Siuchatar1 Siuchatar 105 0.06843 11.7299 0.00142 0.04532 Bharatpur1 Bharatpur 106 1.5265 20.1291 0.004 0.01199 Bharatpur1 Bharatpur 107 1.5265 20.1291 0.004 0.01199 Siuchatar1 Siuchatar 108 0.06843 11.7299 0.00142 0.04532 Bhakatapur Bhaktapur1 109 -41.1766 0.77128 0.01781 0.05344 Dhalkebar-2 Dhalkebar 110 265.4747 -26.6254 0.73474 7.3474 Baneswor Harisidhi 111 -83.3354 6.8236 0.07301 0.21904 New Parwani Parwanipur 112 32.165 4.5772 0.01156 0.03469 Khimti-220 Khimti-132 113 0.01775 -3.7968 0.00013 0.0004 Balaju1 Balaju 114 12.8012 26.1904 0.00863 0.27627 Matatirtha1 Matatirtha 115 32.1395 6.7386 0.011 0.03301

TOTAL GENERATION REAL POWER [MW] 1557.4368 REACTIVE POWER [MVar] 540.6783 TOTAL LOAD REAL POWER [MW] 1497.07 REACTIVE POWER [MVar] 762.252 TOTAL LOSSES REAL POWER [MW] 60.3668 REACTIVE POWER [MVar] -221.5737



12.3.2 Summary of Result As shown above, the active power generation of INPS exceeds its demand in 2013, so some surplus seen is possible to export to India. The power angles of generator buses, including that of Likhu 1 (16.2892) are seen to be within stability limits. The swing bus is also seen to operate within its installed capacity. Likewise, the results show that the voltage profiles of all buses are within 5% of their respective standard values. Also, the transmission lines for the transmission of Likhu 1 HEP, including Khimti-Dhalkebar 220 kV line, are seen to operate within their maximum transfer capability. However, the results also indicate that a deficit of around 200 MVar of reactive power is observed in the INPS system.

12.3.3 Conclusion Considering the installed capacity of about 1600 MW (with the full capacity of the swing bus considered), a surplus of around 475 MW is available in the system, provided that all the upcoming HEP projects and other reinforcements of INPS mentioned above are completed within 2013. Hence, the export of 77 MW of generation from Likhu 1 HEP to India seems acceptable in the scenario. However, the results also point to the fact that complete export of power generated from all the HEPs (afore listed 6 HEPs) may produce adverse impact on INPS in the form of reactive power deficit, although active power generation is at par with the demand. Hence, for the sake of safe power export to India, further reactive power compensation arrangements must be managed by 2013. This may be in the form of some sacrifice in export of power or installation of reactive power compensations at appropriate load centers.

12.3.4 Limitation of Load Flow Study This load flow study considers all installed power plants generation at full capacity, which may not represent the real load flow condition in INPS and is only conceivable during the wet season. This inconsistency is more pronounced during the dry season as almost all HEPs of INPS are run-of-river type, which are likely to reduce the maximum generation capability as compared to the maximum demand. However, power export to India is encouraging due to surplus available in INPS and coincident with the maximum demand of India in the wet season itself. Hence, the scope of this study is limited to impact study of power export to India in the wet season. Hence, the assumptions made here are justified as it represents the worst case scenario during that season. Thus, study supports the concept of power export to India from Likhu 1 HEP during wet season in 2013.



Figure 12.1: Load Flow Analysis of INPS Nepal for 2013

Chapter 12 Load Flow Study DPR Final

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