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46th ISTE Annual National Convention & National Conference 2017 International Journal of Advance Research and Innovation (ISSN 2347 – 3258) Analytical Improvement of Voltage Profile of a 14 Bus Test System using SVC. Nirbhai Singh Gulzar College of Engineering, Khanna Punjab, India [email protected] Vishal Kumar Mittal Gulzar College of Engineering, Khanna Punjab, India [email protected] limits without the necessity of adding new transmission lines. FACTS controllers provide flexibility in power flow control over transmission systems and increase the line loading in some cases up to the maximum limits. These controllers can provide new control facilities both in steady state for the purpose of power flow control. With their ability to change the apparent impedance of transmission line and capability for shunt power compensation, FACTS controllers may be used for active power control, as well as reactive power control or voltage control. FACTS controllers also find important role in restricted electricity marked by increasing system load and the power exchange capability between two areas. Abstract— In modern power system the transmission network become very complex and stressed due to growing demand and constraint on building new transmission line. Due to complex and stressed system, the power system losing stability and voltage profile. The FACTS devices are used to reduced the stress from the transmission line and boost the voltage level of the system. SVC is used to boost the voltage level of the system. In this paper SVC control the power flow and flow of reactive power. In this paper capability of SVC has been checked on IEEE standard 14 bus system. The proposed model analysis the IEEE14 test bus system with and without FACTS device keywords — FACTS, load flow, psat I. INTRODUCTION A Power Generation and Transmission is a complicated process, many devices are used to maximize the output of power system. The active and reactive powers are main part of electrical power, but the reactive power is major part because most industrial loads like motor loads are reactive loads. To improve the AC power system, required to manage the reactive power in well manner. There are two major techniques, which are used to improve the reactive power. One is load compensation and voltage support compensation. In load compensation consist of improve the power factor and balancing of real and reactive power drawn from the supply, for better voltage profile. In large fluctuation the voltage support is required. In recent years static Var compensation like STATCOM and SVC developed. The SVC and STATCOM having special property to absorbed and generate the reactive power with fast response. SVC and STATCOM are allow to improve the transfer of apparent power throw AC transmission line. Flexible AC Transmission system technology is being prompted as a means to extend the capacity of existing power transmission networks to their Selection of study domain: In this dissertation, IEEE 14 bus test system is considered which is investigated under different loading conditions. B Objectives: To improve the voltage profile of IEEE 14 bus test system. C To improve the reactive and active power of IEEE 14 bus test system Methodology: Simulation of IEEE 14 bus test system using PSAT and load flow studies carried out from simulated IEEE 14 bus system in order to investigate the weakest bus of the system. Increment of load at weakest bus of the system and there by investigating the voltage profile of the system. Installation of SVC at weakest bus and there by obtaining the voltage profile of the system. 1 Gulzar Group of Institutes, Ludhiana, Punjab-141401 (INDIA) 46th ISTE Annual National Convention & National Conference 2017 International Journal of Advance Research and Innovation (ISSN 2347 – 3258) buses be ng such that n = np + ng + 1. Bus-1 is assumed to be the slack bus. The approach to Newton-Raphson load flow is similar to that of solving a system of nonlinear equations using the Newton-Raphson method: at each iteration we have to form a Jacobian matrix and his equation is of the form. Comparison of the voltage profile of system with and without SVC . II. LOAD FLOW STUDIES. 2 Vn 2 V2 J V1 n p V1 n p The steady state power and reactive powers supplied by a bus in a power network are expressed in terms of nonlinear algebraic equations. We therefore would require iterative methods for solving these equations. A Real and reactive power injected in a bus The formulation of the real and reactive power entering a bus, we need to define the following quantities. Let the voltage at the ith bus be denoted by Vi Vi i Vi cos i j sin i (1.7) where the Jacobian matrix is divided into sub matrices as (1.1) Define the self admittance at bus-i as Yii Yii ii Yii cosii j sin ii Gii jBii J J 11 J 21 (1.2) Similarly the mutual admittance between the buses i and j can be written as Yij Yij ij Yij cos ij j sin ij P 2 Pn Q2 Q1 n p (1.8) J11: (n 1) (n 1), J12: (n 1) np, J21: np (n 1) Gij jBij and J22: np np The sub matrices are (1.3) Let the power system contains a total number of n buses. The current injected at bus-i is given as P2 2 J11 Pn 2 I i Yi1V1 Yi 2V2 YinVn n YikVk k 1 (1.4) Assume the current entering a bus to be positive and that leaving the bus to be negative. As a consequence the power and reactive power entering a bus will also be assumed to be positive. The complex power at bus-i is then given by Vi n YikViVk k 1 J12 cosik j sinik cos k j sin k J 21 cos i j sin i cosik j sinik cos k j sin k Pi YikViVk cos ik V2 V2 P2 V2 Pn V2 V1 n p V1 n p P2 V1 n p Pn V1 n p (1.10) (4.5) Therefore substituting in (1.5) we get the real and reactive power as n P2 n Pn n (1.9) n Pi jQi Vi I i Vi YikVk k 1 n cos i j sin i YikVk k 1 J 12 J 22 Q2 2 Q1 n p 2 (1.11) J 22 k i k 1 (1.6) Q2 n Q1 n p n Q2 V2 V 2 Q1 n p V2 V2 V1 n p V1 n p Q2 V1 n p Q1 n p V1 n p (4.12) Formation of the Jacobian Matrix We shall now discuss the formation of the sub matrices of the Jacobian matrix. To do that we shall use the real and reactive power equations of (4.6). Let us rewrite them with the help of (4.2) as n Qi YikViVk sin ik k i k 1 B Load flow by Newton-Raphson method Let us assume that an n-bus power system contains a total number of np P-Q buses while the number of P-V (generator) 2 Gulzar Group of Institutes, Ludhiana, Punjab-141401 (INDIA) 46th ISTE Annual National Convention & National Conference 2017 International Journal of Advance Research and Innovation (ISSN 2347 – 3258) Pi Vi 2 M 22 M 2 n J 21 M np 2 M npn n Gii YikViVk cos ik k i k 1 k i (1.13) n Qi Vi Bii YikViVk sin ik k i 2 (1.21) From (4.10) it is evident that the elements of J21 are the partial derivative of Q with respect to . From (4.13) we can write k 1 k i (1.14) A. Formation of J11 Let us define J11 as J11 Q L22 Ln 2 L2 n Lnn M ik M ii n J 12 (1.16) n Qi Vi Bii YikViVk sin ik k i Q i i n Yik Vi Vk cos ik k i k 1 Pi Vi 2 G ii k i N 22 Nn 2 N2n p N nn p Pi YikViVk cos ik k i N ik Vk Vk (1.17) M ik i k (1.25) A. Formation of J11 Let us define J11 as For i = k we have L2 n Lnn Pi N ii Vi Vi (1.18) It can be seen from (1.9) that Mik’s are the partial derivatives of Pi with respect to k. The derivative Pi (1.13) with respect to k for i k is given by n Vi 2 Vi Gii YikVk k 1 k i 2 Vi 2 cos ik k i n G ii YikViVk cos ik k i k 1 2 Vi 2 G ii M ii k i Pi YikViVk sin ik k i , i k k (1.26) Formation of J22 (1.19) Similarly the derivative Pi with respect to k for i = k is given by J 22 n Pi YikViVk sin ik k i i k 1 O22 O2 n p O n p 2 On p n p (1.27) For i k k i Comparing the above equation with (1.39) we can write Lii k (1.24) k 1 k i Lii i k (1.23) k i Lik Formation of J12 Let us define J12 as k 1 L22 J11 Ln 2 Y V V cos , ik i k ik k i (1.22) Pi Vi Gii YikViVk cos ik k i 2 i Similarly for i = k we h (1.15) We shall now discuss the formation of the sub matrices of the Jacobian matrix. To do that we shall use the real and reactive power equations of (1.6). Let us rewrite them with the help of (1.2) as 2 Oik Vi Pi 2 Qi Vi Bii i Qi Vk (1.28) (1.20) Vi Yik ViVk sin ik k i Lik , Finally for i = k we have B. Formation of J21 Let us define J21 as 3 Gulzar Group of Institutes, Ludhiana, Punjab-141401 (INDIA) ik 46th ISTE Annual National Convention & National Conference 2017 International Journal of Advance Research and Innovation (ISSN 2347 – 3258) Qi O ii Vi Vk 2 Vi n Vi 2 Vi Bii YikVk k 1 k i 2 sin ik k i n B ii YikViVk sin ik k i k 1 2 Vi IV. RESULT AND DISCUSSION 2 B ii k i (1.29) We therefore see that once the sub matrices J11 and J21 are computed, the formation of the sub matrices J12 and J22 is fairly straightforward. For large system this will result in considerable saving in the computation time. A Load flow of ieee14 bus system using Newton Rapson method with the help of PSAT software without FACTS. Make the IEEE 14 bus system using PSAT software define its L ii all parameters which are necessary for load flow of IEEE14 bus system e.g. generators, loads, transformer ratings, buses. Convert the 3phase transmission line into pi model of transmission line. Do the load flow of IEEE14 bus system using Newton Rapson method and find all the parameters of IEEE14 bus system. III. POWER FLOW MODEL OF SVC SVC is a shunt connected device. SVC device is belonging to FACTS family, with the use of power electronics SVC control the power flow, and improve the transient stability. SVC also enhances the voltage profile by controlling the reactive power. SVC injects and absorbed the reactive power from the line. When voltage of the system goes low SVC act as a reactive power generator. When voltage goes high SVC absorbed the reactive power from the line. The reactive power variation performed by capacitor bank with electronics switching, each capacitor bank is switching by three SCR. TSC reactor also on off by SCR. Phase control by TCR. Non-linear power equations and the linearised equations required by Newton’s method. Fig 4.1 (IEEE 14 bus system using PSAT) The parameters which are obtained after load flow of IEEE 14 using Newton Rapson methods with the help of PSAT are given below Show in table no 1 the bus No.14 is weakest bus in IEEE 14 bus system. Because the voltage magnitude at 14 number bus is less than all other buses the voltage magnitude at 14 bus is 0.98631 p.u. which is less as comparison to other buses. Take the 14 no bus for analysis. Voltage differential equation can be written as given below X TCR is the reactance of the TCR. Where. Now write the equation in the term of firing angle The reactance of the SVC can be obtained by parallel combination of Xc and X TCR Where. The reactive power equation can be written as given below Fig 4.2(voltage profile without facts) 4 Gulzar Group of Institutes, Ludhiana, Punjab-141401 (INDIA) 46th ISTE Annual National Convention & National Conference 2017 International Journal of Advance Research and Innovation (ISSN 2347 – 3258) V. INCREMENT OF LOAD AT 14 BUS. The bus number 14 is a weakest bus. So bus number 14 is used for analysis. Increased the load at 14 no bus with 5% increment up to 40%. When the load is increased the voltage level decrease at bus no.14.It goes to below the limit which is define at PSAT software during simulation of 14 bus system. The both type of load is increased at bus no.14. the table of load increment at 14 bus is given below. Show in below given diagram as well as the load increased the at bus no 14 the voltage profile decrease. At without load the voltage at bus no.14 is 0.98631 p.u . but as well as load increased the voltage at bus no 14 decreased at 40% load the voltage at bus no. 14 goes to 0.9666 p.u. which is very less than limit which is define at PSAT software. Fig- 6.1 IEEE 14 bus system with SVC using PSAT The application of SVC was initially for load compensation of fast changing loads such as steel mills and arc furnaces. Here the objective is to provide dynamic power factor improvement and also balance the currents on the source side whenever required. The application for transmission line compensators commenced in the late seventies. Here the objectives are: Show in fig the SVC is connected at bus no.14 because the bus no. 14 is the weakest bus in system, so the SVC is connected at bus no. 14. The rating of SVC is power 100 MV, voltage 13.8 KV and frequency 50 Hz. The gain of SVC T2 10 p.u and reference voltage 1.00p.u alpha max 1.00 p.u and alpha minimum -1.00. Km 1.00 p.u, Tm .01p.u. the inductance and capacitance .20Xl p.u and .10 Xc p.u respectively gain is 50p.u. the SVC is device which suck and inject the reactive power to transmission line due to that SVC is used to maintain the reactive power in the transmission line. Show in figure. The SVC is connected at bus no.14.due to SVC the voltage at bus no.14 increase, without SVC the voltage at bus no.14 is 0.98361p.u. But the voltage with SVC 1.0368SSSSp.u.when load is increased at bus no.14. The voltage at bus no.14 decrease, but when SVC is connected at bus no.14 the voltage level increased up to.1.0368 Fig 5.3( load increment at 14 number bus) After the connecting the STATCOM at bus no.14 the value of voltage increase up to 1.04 (p.u) from 0.988. After increasing the load 0% to 40%. The value of voltage decrease without STATCOM but when STATCOM is connected the voltage profile remain constant at 1.04 pu. Show in table no. the value of voltage at bus no.14 is 1.04 p.u. Qgen become 0.09341. Qload is 0.05 VI. LOAD FLOW USING SVC The Static Var Compensator (SVC), first generation FACTS Controller. It is a changeable impedance device where the current through a reactor is controlled using back to back connected thyristor. The function of thyristor valve technology to SVC is an offshoot of the developments in HVDC technology. The major dissimilarity is that thyristor valves used in SVC are rated for minor voltages as the SVC is connected to an EHV line through a step down transformer or connected to the tertiary winding of a power transformer. 5 Gulzar Group of Institutes, Ludhiana, Punjab-141401 (INDIA) 46th ISTE Annual National Convention & National Conference 2017 International Journal of Advance Research and Innovation (ISSN 2347 – 3258) devices,” Electric Power Systems Research, vol. 74, no. 3, pp. 341–351, June 2005. [9]IEEE Working Group, ”Proposed Terms and Definitions for Flexible AC Transmission System (FACTS),” IEEE Trans. PWRD, vol. 12, no. 4, October 1997. pp. 1849-1853 [10]B.R.Gupta, (1998), Power System Analysis And Design, Third Edition , S.Chand and Company Ltd. [11]C.L.Wadhwa, (2005), Electrical Power Systems, Fourth Edition, New Age International Publishers. [12] Claudio A. Canizares, Zen0 T. Faur, “Analysis of SVC and TCSC Controllers in Voltage Collapse”, IEEE Transaction on Power Systems, Vol. 14, No. 1, February 1999, pp. 158- 165 [13]Clark. K., B. Fardanesh, R. Adapa, “Thyristor Controlled Series Compensation Application Study - Control Interaction Considerations,” IEEE Trans. PWRD, vol. 10, no. 2, April 1995, pp. 1031-1037. [14] Alper Cetin, Design and Implementation of VSC based STATCOM For Reactive power Compensation And Harmonic Filtering, Middle East Technical University, 2007. [15]J. H. Chow and K. W. Cheung, “A toolbox for power system dynamics and control engineering education and research,” IEEE Trans. Power Syst., vol. 7, no. 4, pp. 1559– 1564, Nov. 1992 [16]R. D. Zimmerman, C. E. Murrillo-Sánchez, and D. Gan. (2005) Matpower, Version 3.0.0, User’s Manual. Power System Engineering Research Center, Cornell Univ., Ithaca, NY. [Online] Available: http://www.pserc.cornell.edu/matpower/matpower.html [17]C. D. Vournas, E. G. Potamianakis, C. Moors, and T. Van Cutsem, “An educational simulation tool for power system control and stability,” IEEE Trans. Power Syst., vol. 19, no. 1, pp. 48–55, Feb. 2004. Fig-6.2 voltage profile of 14 bus system with SVC. VII. VOLTAGE MAGNITUDE OF IEEE14 BUS SYSTEM AT BUS NO 14 USING SVC. With the study of SVC and STATCOM, improve the reactive power and voltage profile of IEEE 14 bus system. The STATCOM and SVC connect at weakest bus of IEEE 14 bus system. SVC and STATCOM improve the voltage level at weakest bus. The improved voltage level are plots in graphs. Fig 7.2 (comparison of voltage profile using VAR) References [1]B.H. Lee and K.Y. Lee, “Dynamic and static voltage stability enhancement of power systems”, IEEE Trans. Power Syst., vol. 8, pp. 231-238, Feb. 1993. [2]L.L. Freris and A.M. Sasson, “Investigation of the loadflow problem”, Proc. IEE, vol. 115, no. 10, pp. 1450- 1460, Oct. 1968. [3]Hingorani NG, Gyugyi L (1999) Understanding FACTS. IEEE Press, New York [4]Moore P, As3hmole P (1998) Flexible AC transmission systems. Advanced FACTS controllers. Power Eng vol.12 no.2 pp 95–100 [5]Zhang X-P, Rehtanz C, Pal B (2006) Flexible AC transmission systems: modelling and control. Springer, Berlin [6]Kundur, P., Power System Stability and Control, McGrawHill, New York, 1994. [7]H. Ambriz-Perez, E. Acha, and C.R. Fuerte-Esquivel, “Advanced SVC model for newton-raphson load flow and newton optimal power flow studies”, IEEE Trans. Power Syst., vol. 15, no. 1, pp. 129-136, Feb. 2000. [8]P.P. Narayana and M.A. Abdel Moamen, “Power flow control and solutions with multiple and multi-type FACTS 6 Gulzar Group of Institutes, Ludhiana, Punjab-141401 (INDIA)