Reactive Power Compensation Using Capacitor Banks

INTRODUCTION In this chapter we are going to discuss about power system in short and about A.P TRANSCO and its role in maintaining power in state from buying and selling the power 1.1 INTRODUCTION TO POWER SYSTEM Electrical power is a little bit like the air one breathes One doesn't really think about it until it is missing Power is just "there," meeting ones daily needs, constantly It is only during a power failure, when one walks into a dark room and instinctively hits the useless light switch, that one realizes how important power is in our daily life Without it, life can get somewhat cumbersome Electric Energy is the most popular form of energy, because it can be transported easily at high efficiency and reasonable cost The power system of today is a complex interconnected network as shown in fig Figure Power System interconnected A Power System can be subdivided into four major parts: i Generation ii Transmission and Sub transmission iii Distribution iv Loads Power is generated at generating stations, usually located away from the actual users The generated voltage is then stepped up to a higher voltage for transmission, as transmission losses are lower at higher voltages The transmitted electric power is then stepped down at grid stations The modern distribution system begins as the primary circuit, leaves the substation and ends as the secondary service enters the customer's meter socket First, the energy leaves the sub-station in a primary circuit, usually with all three phases The most common type of primary is known as a wye configuration.The wye configuration includes phases and a neutral (represented by the center of the "Y".) The neutral is grounded both at the substation and at every power pole The primary and secondary (low voltage) neutrals are bonded (connected) together to provide a path to blow the primary fuse if any fault occurs that allows primary voltage to enter the secondary lines An example of this type of fault would be a primary phase falling across the secondary lines Another example would be some type of fault in the transformer itself The other type of primary configuration is known as delta This method is older and less common In delta there is only a single voltage, between two phases (phase to phase), while in wye there are two voltages, between two phases and between a phase and neutral (phase to neutral) Wye primary is safer because if one phase becomes grounded, that is, makes connection to the ground through a person, tree, or other object, it should trip out the fused cutout similar to a household circuit breaker tripping In delta, if a phase makes connection to ground it will continue to function normally It takes two or three phases to make connection to ground before the fused cutouts will open the circuit The voltage for this configuration is usually 4800 volts Transformers are sometimes used to step down from 7200 or 7600 volts to 4800 volts or to step up from 4800 volts to 7200 or 7600 volts When the voltage is stepped up, a neutral is created by bonding one leg of the 7200/7600 side to ground This is commonly used to power single phase underground services or whole housing developments that are built in 4800 volt delta distribution areas Step downs are used in areas that have been upgraded to a 7200/12500Y or 7600/13200Y and the power company chooses to leave a section as a 4800 volt setup Sometimes power companies choose to leave sections of a distribution grid as 4800 volts because this setup is less likely to trip fuses or reclosers in heavily wooded areas where trees come into contact with lines For power to be useful in a home or business, it comes off the transmission grid and is stepped-down to the distribution grid This may happen in several phases The place where the conversion from "transmission" to "distribution" occurs is in a power substation A power substation typically does two or three things: i It has transformers that step transmission voltages down to distribution voltages ii It has a "bus" that can split the distribution power off in multiple directions iii It often has circuit breakers and switches so that the substation can be disconnected from the transmission grid or separate distribution lines can be disconnected from the substation when necessary It often has circuit breakers and switches so that the substation can be disconnected from the transmission grid or separate distribution lines can be disconnected from the substation when necessary The primary distribution lines are usually in the range of to 34.5 KV and supply load in well defined geographical area Some small industrial customers are served directly by the primary feeders 1.3 APTRANSCO Government of Andhra Pradesh enacted the AP Electricity REFORMS ACT in 1998.As a sequel the APSEB was unbundled into Andhra Pradesh Power Generation Corporation Limited (APGENCO) & Transmission Corporation of Andhra Pradesh Limited (APTRANSCO) on 01.02.99 APTRANSCO was further unbundled w.e.f 01.04.2000 into "Transmission Corporation" and four "Distribution Companies" (DISCOMS) a.)CURRENT ROLE From Feb 1999 to June 2005 APTRANSCO remained as Single buyer in the state -purchasing power from various Generators and selling it to DISCOMs in accordance with the terms and conditions of the individual PPAs at Bulk Supply Tariff (BST) rates Subsequently, in accordance with the Third Transfer Scheme notified by Go AP, APTRANSCO has ceased to power trading and has retained with powers of controlling system operations of Power Transmission 1.4 CONCLUSION In this chapter we discussed about the power system and role of A.P TRANSCO in the state of A.P In next chapter we are going to discuss about the salient features of A.PTRANSCO INTRODUCTION In this chapter, we are going to discuss about the salient feature of A.P TRANSCO/A.PGENCO/DISCOMS The object of reform and restructure of power sector in the state is to create conditions for sustainable development of the sector through promoting competition, efficiency, transparency and attracting the much needed private finances into power sector The ultimate goal of the reform program is to ensure that power will be supplied under the most efficient conditions in terms of cost and quantity to support the economic development of the state and power sector ceases to be a burden on the States budget and eventually becomes a net generator of resources A key element of the reform process is that the government will withdraw from its earlier role as a regulator of the industry and will be limiting its role to one of policy formulation and providing directions In accordance with Reform Policy, the Government of A.P entacted the A.P Electricity Reforms Act 1998 and made effective from 1.2.1999 Transmission Corporation of A.P Ltd (APTRANSCO and APGENCO) were incorporated under Companies Act, 1956 The assets, liabilities and personnel were allocated to these companies Distribution companies have been incorporated under Companies Act as subsidiaries to distribution to APTRANSCO and the assets, liabilities and personnel have been allocated to distribution companies through notification of a second transfer scheme by the Govt on 31.3.2000 The Government of A.P established the A.P Electricity Regulatory Commission (APERC) as per the provision of the act and the Commission started functioning from 3.4.1999 Regular licenses have been issued to APTRANSCO by APERC for Transmission and Bulk supply and Distribution and Retail supply from 31.1.2000 The commission has been issuing yearly Tariff orders since then based on Annual Revenue Requirement (ARR) and tariff proposals of these companies 2.2 SALIENT FEATURES OF A.P TRANSCO/A.PGENCO/DISCOMS Table 2.2 (a) features of A.P power system PARAMETER UNITS 2008-09 31.03.09 2009-10 (UPTO (UPTO MARCH (PROVL) 09) Energy generated (cumulative) Thermal 31.03.10 MARCH (PROVL) 10) MU MU - 23325.67 - 24180.38 7785 - 5510.46 Hydel MU - Wind MU - - - - Total MU - 31110.67 - 29690.84 Energy purchased and imported MU - 36511.56 - 45075.68 (includingother’s energy handled) Energy available for use (2+3) MU - 67622.23 - 74766.52 - 9997 - 10880 Maximum demand during the year ME (at generation terminal) MW (27-03PercpaitaConsumption (includes captive generation) APTRANSCO LINE (EHT) 400kv 220kv 132kv DISCOM’S Lines # 33kv 11kv LT TOTAL KWH - CKM CKM CKM Km Km km - (21-03-2010) 2009) 746 - - 21.44 265.88 233.02 3008.20 1250.25 14938.57 24 19068 164.88 3032.79 12693.18 15103.45 1421.78 19521.82 10166.53 26630.14 38628 248670 527852 845599.15 1230 10596 4212 6418.17 39858 259266 532064 862017.32 Table 2.2 (b) load generation and sharing of A.P with other state Parameter Units 2008-09 31.03.09 2009-10 31.03.10 (upto march09) (Provl) (upto march10) (Provl) Installed Capacity a) A.P.GENCO Thermal Hydel Wind MW Total A.P.GENCO 3382.50 1000.00 4382.50 MW 39.0 3664.36 39.00 3703.56 MW 39.0 2.00 - 2.00 1039.00 8087.86 7048.86 b) Joint Sector Gas(A.P.G.P.C.L) MW - 272.00 - 272.00 Thermal MW - - - - Gas MW - - - - Mini Hydel MW - - - - Wind MW Co-generation & Bio mass MW - - - - - - - - - - - - c) Private Sector - projects Others(IsoGasWells+Wast MW - e heat +indl Waste + Muncipal waste ) TOTAL - PRIVATE SECTOR d) Share MW from Central Sector Ramagundam STPS MW - - -5.65 913.46 M.A.P.P (madras atomic MW - - -0.25 46.84 - - -1.94 344.10 - -0.98 147.34 - 5.31 77.67 - - 1000 3.77 437.07 85.06 85.06 - - - - power plant) Neyveli Lignite MW corporation Kaiga nuclear power plant MW I &II Kaiga nuclear power plant MW III MW - Simhadri TPS MW - Talcher (ph -II) units -3,4,5,6 MW - Unallocated power from eastern region TOTAL SHARE FROM MW 0.00 2963.22 85.22 3048.54 CENTRAL SECTOR TOTAL(A.P GENCO MW 45.66 12427.25 2114.40 14541.65 +PRIVATE +CENTRAL ) 2.3 CONCLUSION In this chapter, we discussed about the salient features of A.PTRANSCO / A.PGENCO / DISCOMS In next chapter we are going to discuss about the need for compensation and types of compensations used 3.1 INTRODUCTION In this chapter, reactive power compensation, mainly in transmission systems installed at substations is discussed Reactive power compensation in power systems can be either shunt or series Except in a very few special situations, electrical energy is generated, transmitted, distributed, and utilized as alternating current (AC) However, alternating current has several distinct disadvantages One of these is the necessity of reactive power that needs to be supplied along with active power Reactive power can be leading or lagging While it is the active power that contributes to the energy consumed, or transmitted, reactive power does not contribute to the energy Reactive power is an inherent part of the ‘‘total power.’’ Reactive power is either generated or consumed in almost every component of the system, generation, transmission, and distribution and eventually by the loads The impedance of a branch of a circuit in an AC system consists of two components, resistance and reactance Reactance can be either inductive or capacitive, which contribute to reactive power in the circuit Most of the loads are inductive, and must be supplied with lagging reactive power It is economical to supply this reactive power closer to the load in the distribution system 3.2 TYPES OF COMPENSATION Shunt and series reactive compensation using capacitors has been widely recognized and powerful methods to combat the problems of voltage drops, power losses, and voltage flicker in power distribution networks The importance of compensation schemes has gone up in recent years due to the increased awareness on energy conservation and quality of supply on the part of the Power Utility as well as power consumers This amplifies on the advantages that accrue from using shunt and series capacitor compensation It also tries to answer the twin questions of how much to compensate and where to locate the compensation capacitors i.) SHUNT CAPACITOR COMPENSATION Since most loads are inductive and consume lagging reactive power, the compensation required is usually supplied by leading reactive power Shunt compensation of reactive power can be employed either at load level, substation level, or at transmission level It can be capacitive (leading) or inductive (lagging) reactive power, 10 above will have many other factors viz., seasonal fluctuations, temporary change over of loads etc, influencing the results Table no.7.1 (d) calculation of cost benefits Sl.no Particulars Line current(in amps) feeder with 129 feeder 135 feeder 176 capacitor Line current(in amps) with 114 118 154 capacitor Difference in current(in amps) Percentages savings 17 13% 22 13% 15 12% Reduction in line current is of order of 12-13 percent and so is the reduction in demand This has also resulted in improvement of tail end voltages by to 3% c.) COST BENEFIT ANALYSIS: The benefit from installation of capacitors will be in the form of reduction in loading of transmission and distribution network This in turn results in reduction in energy losses The pay back period has been worked out by considering the savings in terms power purchase cost to Bescom, which works out to 8.5 months The benefits available from the transmission system are not considered as the same are in the KPTCL preview Detailed calculations are furnished below:Table no.7.1 (e) cost benefit analysis Sl.no Particulars Line current Feeder without 129 Feeder2 136 Feeder3 176 capacitor 68 Line current with capacitor 114 Difference in current 15 Power factor with out 0.65 118 17 0.73 154 22 0.84 capacitor Power factor out 0.87 0.96 0.90 capacitor Demand(in KVA)with out 2458 2572 3353 capacitor bank Demand(in 2248 2934 capacitor bank Reduction in demand in 287 324 419 10 KVA % Reduction in demand 11.7% Feeder loss reduction on 133.59 12.6% 290.32 12.5% 490.02 11 11KV side keh per day Savings per day taking 367 798 1348 12 purchase rate of RS.2.75 Total saving /months from 75,390 - - 13 all the three feeder Total cost of capacitors 5x2,12,998=10,64,990 - - 14 banks Pay back period - with KVA)with 2171 14 months - Installation of Capacitor Bank to 11KV Feeders at D.B PUR For the calculation of feeders losses a) resistance of rabbit conductor is considered b) line length of 4.5 KMs is considered 69 c) Capacitor bank is assumed to work our hours in a day d.) GUIDELINES FOR REPEATABILITY IN OTHER DISTRIBUTED AREAS: Since this is a simple devise and does not require any special skill or effort for execution and requires only a minimum shutdown of lines, the APTRANSCO can reap considerable benefit by executing such projects By installing 63 capacitors banks on 31 feeders, the subdivision is benefited in terms of reduction losses and improved quality of power supply 7.2 CASE STUDY – 2: The case studies regarding Shahpurnagar and Kalyan nagar substations are discussed below The corresponding results and conclusions before and after the compensation are tabulated below a.) RESULTS OF CASE STUDY –KALYAN NAGAR: BEFORE COMPENSATION Receiving Node Sending Node B.No Table no.7.2 (a) readings before compensation at Kalyan nagar 4 SENDING Injecting Real Power P (Pu) P[1]=0.45458 P[2]=0.45400 P[3]=0.40479 P[4]=0.30956 Injecting Reactive Power Q (Pu) Q[1]=0.43743 Q[2]=0.43713 Q[3]=0.39496 Q[4]=0.31159 Receivin g end Voltage 1.00000 0.99484 0.97006 0.95547 Real Power Losses (Kw) 2.9958 12.4262 19.2551 40.4721 Reactiv e Losses (KVAR) 1.5271 6.3290 2.5611 9.1239 Power Factor 0.7206 0.7204 0.7157 0.7048 70 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 10 11 12 13 14 15 16 17 19 20 21 23 24 26 27 28 29 30 31 32 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 P[5]=0.27830 P[6]=0.23183 P[7]=0.12894 P[8]=0.10807 P[9]=0.08086 P[10]=0.06090 P[11]=0.05124 P[12]=0.04607 P[13]=0.03881 P[14]=0.02798 P[15]=0.01422 P[16]=0.00637 P[17]=0.00294 P[2]=0.01292 P[19]=0.03621 P[20]=0.02717 P[21]=0.01791 P[3]=0.00886 P[23]=0.07381 P[24]=0.06438 P[6]=0.03164 P[26]=0.08785 P[27]=0.08158 P[28]=0.07532 P[29]=0.06849 P[30]=0.05593 P[31]=0.04565 P[32]=0.03020 Q[5]=0.30746 Q[6]=0.29755 Q[7]=0.19929 Q[8]=0.19514 Q[9]=0.18865 Q[10]=0.18239 Q[11]=0.17901 Q[12]=0.17820 Q[13]=0.17750 Q[14]=0.17341 Q[15]=0.16953 Q[16]=0.16710 Q[17]=0.16517 Q[2]=0.15908 Q[19]=0.03701 Q[20]=0.03680 Q[21]=0.03539 Q[3]=0.03515 Q[23]=0.07687 Q[24]=0.07640 Q[6]=0.07497 Q[26]=0.08967 Q[27]=0.06775 Q[28]=0.06083 Q[29]=0.05832 Q[30]=0.05727 Q[31]=0.05648 Q[32]=0.04408 0.94115 0.90603 0.89259 0.85335 0.83187 0.81227 0.81007 0.80608 0.77953 0.76486 0.75438 0.74400 0.71326 0.70392 0.99387 0.98632 0.98429 0.98100 0.96520 0.95561 0.94863 0.90356 0.90054 0.88801 0.87908 0.87502 0.86568 0.86326 9.0420 0.8717 7.2121 3.9541 3.6644 0.6720 1.2558 4.8358 1.7573 1.8524 2.3082 3.9737 0.0358 0.0363 0.2607 0.0542 0.0786 0.4235 0.7479 0.5043 0.2644 0.2653 0.8286 0.5558 0.2824 0.4496 0.0789 0.0460 7.8055 2.8815 5.2049 2.8408 2.5974 0.2222 0.4153 3.8047 2.3132 1.6487 1.6856 5.3055 0.0342 0.0347 0.2349 0.0633 0.1040 0.2893 0.5906 0.3946 0.1347 0.1351 0.7305 0.4842 0.1438 0.4443 0.0920 0.0715 0.6711 0.6146 0.5432 0.4845 0.3939 0.3167 0.2752 0.2503 0.2136 0.1593 0.0836 0.0381 0.0178 0.0809 0.6993 0.5940 0.4516 0.2444 0.6926 0.6444 0.3888 0.6998 0.7693 0.7780 0.7614 0.6987 0.6286 0.5652 AFTER COMPENSATION Table no.7.2 (b) readings after compensation at Kalyan nagar SENDING 71 B.No Sending Node Receiving Node Injecting Real Power P (Pu) 1 P[1]=0.43214 Q[1]=0.38253 1.00000 2.5093 1.2792 0.7488 2 P[2]=0.43164 Q[2]=0.38228 0.99523 10.1106 5.1496 0.7486 3 P[3]=0.38292 Q[3]=0.33555 0.97257 14.7593 1.9631 0.7521 4 P[4]=0.28990 Q[4]=0.25065 0.95959 30.4874 6.8730 0.7565 5 P[5]=0.26314 Q[5]=0.24068 0.94694 6.6732 5.7607 0.7379 6 P[6]=0.22666 Q[6]=0.22981 0.91656 0.5151 1.7028 0.7022 7 P[7]=0.12539 Q[7]=0.13257 0.90706 3.6168 2.6102 0.6872 8 P[8]=0.10487 Q[8]=0.11887 0.87735 1.6001 1.1496 0.6616 9 10 P[9]=0.08126 Q[9]=0.10426 0.86221 1.1801 0.8365 0.6147 10 10 11 P[10]=0.0636 Q[10]=0.0911 0.84939 0.1961 0.0648 0.5728 11 11 12 P[11]=0.0564 Q[11]=0.0862 0.84777 0.3383 0.1119 0.5477 12 12 13 P[12]=0.0517 Q[12]=0.0832 0.84488 1.1667 0.9180 0.5284 13 13 14 P[13]=0.0454 Q[13]=0.0795 0.82938 0.3759 0.4947 0.4958 14 14 15 P[14]=0.0382 Q[14]=0.0751 0.82198 0.2992 0.2663 0.4537 15 15 16 P[15]=0.0259 Q[15]=0.0666 0.81692 0.3192 0.2331 0.3621 16 16 17 P[16]=0.0196 Q[16]=0.0624 0.81200 0.4600 0.6141 0.2996 17 17 18 P[17]=0.0122 Q[17]=0.0581 0.80022 0.0357 0.0340 0.2065 18 19 P[2]=0.00582 Q[2]=0.05357 0.79661 0.0358 0.0341 0.1080 19 19 20 P[19]=0.0362 Q[19]=0.0364 0.99426 0.2149 0.1937 0.7048 20 20 21 P[20]=0.0271 Q[20]=0.0314 0.98732 0.0330 0.0385 0.6542 21 21 22 P[21]=0.0179 Q[21]=0.0252 0.98570 0.0291 0.0385 0.5801 22 23 P[3]=0.00893 Q[3]=0.02018 0.98358 0.4120 0.2815 0.4046 23 23 24 P[23]=0.0739 Q[23]=0.0747 0.96778 0.6731 0.5315 0.7031 24 24 25 P[24]=0.0644 Q[24]=0.0694 0.95863 0.2745 0.2148 0.6804 Injecting Reactive Power Q (Pu) Receivin g end Voltage Real Power Losses (Kw) Reactiv e Losses (KVAR) Power Factor 72 25 26 P[6]=0.03182 Q[6]=0.05094 0.95309 0.2601 0.1325 0.5298 26 26 27 P[26]=0.0885 Q[26]=0.0874 0.91412 0.2516 0.1281 0.7116 27 27 28 P[27]=0.0823 Q[27]=0.0623 0.91119 0.7527 0.6636 0.7972 28 28 29 P[28]=0.0760 Q[28]=0.0522 0.89946 0.4784 0.4168 0.8245 29 29 30 P[29]=0.0693 Q[29]=0.0465 0.89134 0.2094 0.1066 0.8302 30 30 31 P[30]=0.0568 Q[30]=0.0391 0.88773 0.2775 0.2743 0.8237 31 31 32 P[31]=0.0466 Q[31]=0.0330 0.88054 0.0315 0.0367 0.8161 32 32 33 P[32]=0.0313 Q[32]=0.0127 0.87919 0.0039 0.0061 0.9263 Reactiv e Losses (KVAR) Power Factor req=0.11229p.u xeq=0.14530p.u b.)RESULTS OF CASE STUDY – SHAHPURNAGAR: BEFORE COMPENSATION B.No Sending Node Receiving Node Table no.7.2(c) readings before compensation at Shahpur nagar SENDING 1 P[1]=0.12752 Q[1]=0.12979 1.00000 0.3602 1.1926 0.7288 2 P[2]=0.12728 Q[2]=0.12953 0.99584 0.7441 1.1570 0.7289 3 P[3]=0.11492 Q[3]=0.11677 0.98846 0.6723 0.4909 0.7014 4 P[4]=0.07059 Q[4]=0.07692 0.98055 0.7965 0.7022 0.6761 Injecting Real Power P (Pu) Injecting Reactive Power Q (Pu) Receivin g end Voltage Real Power Losses (Kw) 73 5 P[5]=0.05792 Q[5]=0.07486 0.96950 0.8258 1.1289 0.6119 6 P[6]=0.04812 Q[6]=0.07298 0.95363 0.3460 0.3080 0.5504 7 P[7]=0.03929 Q[7]=0.07114 0.94837 0.0591 0.0301 0.4835 P[3]=0.01895 Q[3]=0.06956 0.93810 0.1195 0.0609 0.2628 9 10 P[9]=0.03759 Q[9]=0.03791 0.98605 0.0729 0.0373 0.7041 10 10 11 P[10]=0.01947 Q[10]=0.03750 0.98446 0.0977 0.0739 0.4608 11 11 12 P[11]=0.01340 Q[11]=0.03668 0.98180 0.0234 0.0119 0.3431 AFTER COMPENSATION Table no.7.2(d) readings after compensation at Shahpur nagar Receiving Node 1 P[1]=0.12765 Q[1]=0.12478 1.00000 0.3658 1.2111 0.7351 2 P[2]=0.12740 Q[2]=0.12451 0.99680 0.7354 1.1434 0.7352 3 P[3]=0.11503 Q[3]=0.11530 0.98848 0.6312 0.4609 0.7063 4 P[4]=0.07065 Q[4]=0.07240 0.98077 0.6625 0.5841 0.6984 5 P[5]=0.05801 Q[5]=0.06394 0.97057 0.6069 0.8296 0.6719 6 P[6]=0.04835 Q[6]=0.05736 0.95698 0.2204 0.1961 0.6445 7 P[7]=0.03974 Q[7]=0.05153 0.95261 0.1190 0.0606 0.6107 P[3]=0.01952 Q[3]=0.03933 0.94550 0.1192 0.0607 0.4446 9 10 P[9]=0.03765 Q[9]=0.03775 0.98607 0.0469 0.0240 0.7061 10 10 11 P[10]=0.01953 Q[10]=0.02769 0.98468 0.0475 0.0360 0.5764 11 11 12 P[11]=0.01348 Q[11]=0.02367 0.98265 0.0086 0.0044 0.4950 B.No Sending Node SENDING Injecting Real Power P (Pu) Injecting Reactive Power Q (Pu) req=0.11229p.u Receivi ng end Voltage Real Power Losses (Kw) Reacti ve Losses (KVAR) Power Facto r xeq=0.14530p.u c.)COMPARISION OF TEST SYSTEMS: Voltage comparison of a 12 Bus system 74 Table no.7.2 (e) Readings of Voltage comparison Voltage before compensation Voltage after compensation 1 0.99584 0.9968 0.98846 0.98848 0.98055 0.98077 0.9695 0.97057 0.95363 0.95698 0.94837 0.95261 0.9381 0.9455 0.98605 0.98607 0.98446 0.98468 0.9818 0.98625 Power factor comparison of a 12 Bus system Table no.7.2 (d) Readings Power factor comparison Power factor before compensation Power factor after compensation 0.7288 0.7351 0.7289 0.7352 0.7014 0.7063 0.6761 0.6984 0.6119 0.6719 0.5504 0.6445 0.4835 0.6107 0.2628 0.4446 0.7041 0.7061 0.4608 0.5764 0.3431 0.495 75 Voltage comparison of a 33 Bus system Table no.7.2 (e) Voltage comparison of a 33 Bus system Voltage before compensation Voltage after compensation 1 0.99484 0.99523 0.97006 0.97257 0.95547 0.95959 0.94115 0.94694 0.90603 0.91656 0.89259 0.90706 0.85335 0.87735 0.83187 0.86221 0.81227 0.84939 0.81007 0.84777 0.80608 0.84488 0.77953 0.82938 0.76486 0.82198 0.75438 0.81692 0.744 0.812 0.71326 0.80022 0.70392 0.79661 0.99387 0.99426 0.98632 0.98732 0.98429 0.9857 0.981 0.98358 76 0.9652 0.96778 0.95561 0.95863 0.94863 0.95309 0.90356 0.91412 0.90054 0.91119 0.88801 0.89946 0.87908 0.89134 0.87502 0.88773 0.86568 0.88054 0.86326 0.87919 Power factor compensation of a 33 Bus system Table no.7.2 (f) Power factor compensation of a 33 Bus system Power factor before compensation Power factor after compensation 0.7206 0.7488 0.7204 0.7486 0.6711 0.7379 0.6146 0.7022 0.5432 0.6872 0.4845 0.6616 0.3939 0.6147 0.3167 0.5728 0.2136 0.4958 0.0381 0.2996 0.0178 0.2065 0.0809 0.108 0.6993 0.7048 77 0.594 0.6542 0.4516 0.5801 0.2444 0.4046 0.6926 0.7031 0.6444 0.6804 0.7614 0.8302 0.6987 0.8237 0.6286 0.8161 0.5652 0.9263 8.1 CONCLUSION The power factor of a power system is the major of its economy So, the design Engineers always attempts to make this power factor as close as to unity Power factor decreases due to the increased usage of inductive loads Therefore the power distribution companies always sets up a mandatory minimum power factor at the premises of consumers In our state the mandatory power factor is 0.9 described by the Andhra Pradesh Transmission Corporation The decrease in power factor below this reference is compensated by the consumer based on their maximum demand and the no of units consumed Hence, to compensate for this decrease in power factor shunt capacitor method can be used as its advantages are already described in Chapter Proper analysis design and implementation of this capacitor banks with appropriate mounting and protecting devices will not only reduce the bill charges but also make the profit on long term 8.2 Future trends of the project: 78 The electricity consumption depends upon the infrastructure, instruments and different loads Hyderabad area is going to consume more loads in future with increase in population Practical implementation of the capacitor placement technique requires further cost-benefit analysis which in turns depends on the costs of capacitor bank and energy saving Technical Reference Book - A.P.TRANSCO A.S PABLA, “Electrical Power Distribution” fifth edition TATA Mc Graw-Hill Publication Company Limited, New Delhi – 20 TURAN GONEN, “Electrical Power Distribution System Engineering”, TATA Mc GRAW-HILL, book Company, New York Suresh Kumar “Application of Capacitors” B.R GUPTA “Power System Analysis & Design” 3rd Edition, wheeler Publishers C.L.Wadhwa, Power Systems,4th Edition, New Age International (P) Limited,Publishers-1998 L.Elgerd Olle, An Introduction To Energy Systems, 2nd edition, Tata Mac Graw Hill, Inc Edition 79 APPENDIX-I The Karnataka Power Transmission Corporation Limited, also known as KPTCL is the sole electricity transmission and distribution company in state of Karnataka of India (Bharath ) Its origin was in Karnataka Electricity Board ( K.E.B ) which was earlier sole distributor of grid electricity in state of Karnataka This electricity transmission and distribution entity was corporatised to provide efficient and reliable electric power supply to the people of Karnatak state.The KPTCL has transmission lines along with Substation to transfer electricity from one place to another in the state KPTCL buys power from power generating companies like Karnataka Power Corporation Limited (KPCL) and other IPPs (Independent Power Producers) like GMR, Jindal, etc., and sell them to their respective ESCOMS.The electric generating power stations previously under the control of K.E.B has now transferred to a separate company called Visweshraiah Vidyut Nigama Limited or VVNL Zones and Circles The KPTCL is further divided into Zones and Circles are also known as Electric Supply Companies popularly known as ESCOM's Each of these zones look after distribution of electricity in a particular region of Karnataka consisting of few districts of 80 the state Whereas KPTCL looks after transmission The KPTCL has five zones at present, names of which is as below i Bangalore Electricity Supply Company ii Mangalore Electricity Supply Company ( Mescom ) iii Hubli Electricity Supply Company iv Gulbarga Electricity Supply Company v Chamundeshwari Electricity Supply Company APPENDIX - II • Average load: Average of the load occurring on the power station in a given period is known as average load • Capacity factor: It is the ratio of actual energy produced to maximum possible energy that could have been produced during a given period • Connected load: It is the sum of continuous rating of all the equipment connected to supply system • Demand factor: It is the ratio of maximum demand on power station to its connected load • Depreciation: The decrease in the value of the power plant equipment and building due to constant use is known as depreciation • Diversity factor: The ratio of sum of individual maximum demands to the maximum demand on power station • Fixed cost: It is the cost which is independent of maximum demand and unit generated • Interest: The cost of use of money is known as interest • Load curve: The curve showing the variation of the load on the power station with reference to time is known as load curve 81 • Load factor: The ratio of average load to maximum demand during a given period • Maximum demand: It is the greatest demand of load on power station during a given period • Payback period: The time between which capital cost is compensated from the day of installation is known as payback period • Running cost: It is the cost which depends only upon the number of unit generated 82 [...]... 4.4 LOCATION OF CAPACITOR BANKS: Depending upon specific factors such as cost, requirement of area for installation and load, the location of capacitor banks is divided into three types They are, a Central compensation b Group compensation c Individual compensation a) CENTRAL COMPENSATION: When the main purpose is to reduce reactive power purchase due to power supplier’s tariffs, central compensation. .. types of capacitor banks and their ratings In next chapter we are going to discuss about latest technology involved in reactive power compensation 35 5.1 INTRODUCTION In this chapter we are going study about latest technology involved in reactive power compensation 5.2 STATIC VAR CONTROL (SVC): Static VAR compensators, commonly known as SVCs, are shunt connected devices; vary the reactive power output... keep the compensation at economically optimum level throughout the day However, 17 this can only be approximated by switched capacitor banks Usually one fixed capacitor and two or three switched units will be employed to match the compensation to the reactive demand of the load over a day The value of fixed capacitor is decided by minimum reactive demand as shown in Fig 3.2 (v) Figure 3.2 (v) reactive. .. The required capacitor output may be calculated as follows: select the factor (matching point of actual and target power factor) k calculate the required capacitor rating with the formula: Qc = k * P Example: actual power factor = 0.70, target power factor = 0.96, real power = P = 500kW, Qc = k * P = 0.73 * 500kW = 365 KVAR 4.3 INSTALLATION OF CAPACITORS: In the case of induction motors, power factor... compensation they can be used for delivering more power without overloading the equipment Reactive power compensation in a power system is of two types—shunt and series Shunt compensation can be installed near the load, in a distribution substation, along the distribution feeder, or in a transmission substation Each application has different purposes Shunt reactive compensation can be inductive or capacitive... lagging power factor with the bus connected shunt capacitor bank improves the power factor and reduces current flow through the transmission lines, transformers, generators, etc This will reduce power losses (I2R losses) in this equipment iii Increased utilization of equipment: Shunt compensation with capacitor banks reduces KVA loading of lines, transformers, and generators, which means with compensation. .. mainly in transmission systems and the types of compensations of which shunt and series are the main compensation techniques In next chapter we are going to discuss about the different types of capacitor banks and their ratings 4.1 INTRODUCTION: 25 In this chapter we are going to discus about the different types of capacitor banks and their ratings A capacitor consists of two electrodes or plates,... power distribution system calculation and selection of required capacitor rating Qc = P * {tan [acos (pf1)] - tan [ acos (pf2)]} Qc = required capacitor output (kVAr) pf1 = actual power factor pf2 = target power factor P = real power (kW) The table below shows the values for typical power factors in accordance with the above formula Actual Power Factor 30 0.7;0.75;0.8;0.85;0.9;0.92;0.94;0.96;0.98;1 ... Since the load power factor is always lagging, a shunt connected capacitor bank at the substation 15 can raise voltage when the load is high The shunt capacitor banks can be permanently connected to the bus (fixed capacitor bank) or can be switched as needed Switching can be based on time, if load variation is predictable, or can be based on voltage, power factor, or line current ii Reducing power losses:... resistance R The power loss is (Ij2+ I22)RThe power loss due to reactive component is I22 R Compensating the feeder will result in a change only in I2 Hence the new power loss will be (I22+(I2-IC) 2) R where Ic is the compensating current Hence the decrease in power loss due to compensating part of reactive current is (2 I2Ic-Ic2) R Now, if I2 is varying (it will be varying according to reactive demand ... compensation capacitors i.) SHUNT CAPACITOR COMPENSATION Since most loads are inductive and consume lagging reactive power, the compensation required is usually supplied by leading reactive power. .. the energy consumed, or transmitted, reactive power does not contribute to the energy Reactive power is an inherent part of the ‘‘total power. ’’ Reactive power is either generated or consumed... system 3.2 TYPES OF COMPENSATION Shunt and series reactive compensation using capacitors has been widely recognized and powerful methods to combat the problems of voltage drops, power losses, and