ScienceDirect. Optimization active and reactive power flow for PV connected to grid system using Newton Raphson method

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1 Available online at ScienceDirect Energy Procedia 68 (2015 ) nd International Conference on Sutainable Energy Engineering and Application, ICSEEA 2014 Optimization active and reactive power flow for PV connected to grid ytem uing Newton Raphon method Refdinal Nazir a, *, Kiki Kanada a, Syafii a, Prima Coveria a a Andala Univerity, Padang-25163, Indoneia Abtract The application of olar power plant connected to the utility grid could be one olution in reducing the ue of foil fuel a primary energy power plant.currently, the ue of olar energy to upply electricity on the on-grid area i growing rapidly. Thi paper propoe a imple method to optimize the power delivery of photovoltaic (PV) ytem to the utility grid. Two variable, the inverter output voltage V int and power angle, i determined from the root of two imultaneou Eq., active and reactive power in order to find the maximum and minimum reactive power. Newton Raphon method ued to olve the root of the two Eq. imultaneouly. The value of V int correponding to the root equation i done by adjuting the amplitude modulation of the inverter.hence, the et i done by hifting the phae angle of the reference wave of the inverter. In thi model, 10 PV module type of ND T060M1 with a 60 Wp capacity are ued. The imulation reult uing SIMULINK-MATLAB have a pretty good performance. The voltage at the PCC point ha reached it table value at 220Volt. Simulation reult have hown the maximum value of the active power ytem at 1000 W/m 2 irradiation wa 408 W, a the reactive power i needed only Var. The olar power can work in a power factor approaching unity with the application of the propoed method i uggeted The Author. Publihed by Elevier Ltd. Thi i an open acce article under the CC BY-NC-ND licene 2015 The Author. Publihed by Elevier B.V. ( Peer-review under reponibility of Scientific Committee of ICSEEA Peer-review under reponibility of Scientific Committee of ICSEEA 2014 Keyword:optimalization;power flow; PV;grid ytem; Newton Raphon method 1. Introduction The utilization of olar energy to upply electricity on the on-grid area i growing rapidly at thi time. There are variou thing that upport thi condition. The government policy that upport beneficiarie photovoltaic a the * Correponding author. Tel.: ; fax: addre: refdinalnazir@yahoo.co.id The Author. Publihed by Elevier Ltd. Thi i an open acce article under the CC BY-NC-ND licene ( Peer-review under reponibility of Scientific Committee of ICSEEA 2014 doi: /j.egypro

2 78 Refdinal Nazir et al. / Energy Procedia 68 ( 2015 ) ditributed generation on grid utility. The application of PV ytem connected to the utility grid can reduce/remove the need batterie, o cot of energy become cheaper. Often, the contruction of a PV ytem can benefit from the roof of a houe or building, o the pecial land i not required. The main problem of the PV ytem connected to the utility grid i how to maximize the output power of the PV for all unhine condition and optimize ending it to the utility grid. Hence, a control ytem of PV connected to the utility grid can be grouped into two part, namely Maximum Power Point Tracking (MPPT) control and inverter control [1]. MPPT control ued to maximize the power output of the PV for all unhine and temperature condition. In the meantime, optimizing delivery of electrical power from the PV ytem to the utility grid i done by inverter control. Currently, the tudy of MPPT control to maximize the power output of the PV ha grown rapidly [1-4]. The Perturb-and-Oberve (P&O) method ha been developed by K. Chomuwan et al. (1995) and W. Xiao et al. (2004) the Open-and-Short-Circuit method ha been propoed by T. Noguchi et al. (2002) Incremental Conductance Algorithm ha been developed by C. Hua et al. (1998). C. Liu & R. Cheung (2004) ha propoed a method of Etimate-Perturb-Perturb (EPP), Fuzzy Logic and Neural Fuzzy algorithm ha been propoed by N. Patcharaprakiti et al. (2006) and R. Ika Putri et al. (2012). The inverter control i required by the PV ytem to optimize the delivery of power to the utility grid. In other word, the active power delivered to the utility grid on a maximum value with unity power factor or no reactive power generated/aborbed by the ytem. A number of the literature agreed [5-8] that in order to optimize the delivery of electrical power from the inverter to the grid i done by etting the output voltage of the inverter and the angle angle. In thi paper, a imple method i propoed to optimize the power delivery of PV ytem to the utility grid. The inverter output voltage Vint and phae angle α, i olved from the root of two imultaneou Eq., active and reactive power equation, in order to find the maximum and minimum reactive power. Newton Raphon method ued to olve the root of the two Eq. imultaneouly. 2. Sytem decription 2.1. Configuration of propoed ytem The configuration of propoed ytem conit of PV generator, DC Capacitor, SPWM Inverter, filter, tep-up tranformer, load and grid a hown in Fig. 1. PV array i contructed by 10 PV module connected in erie. DC capacitor erve to maintain the tability of voltage input inverter. DC ytem i converted by the inverter to AC ytem uing the method of Sinuoidal Pule Width Modulation (SPWM). In thi propoed ytem, the utility grid will upply power to the load if the power from the PV ytem doe not uffice, or will aborb the power from the PV ytem i exceeded. Fig. 1. Configuration of propoed ytem

3 Refdinal Nazir et al. / Energy Procedia 68 ( 2015 ) PV module The main component of the olar power plant i the photovoltaic (PV). In General, the PV ha a paraitic reitance in erie and parallel, a hown in Fig. 2. Characteritic of PV are highly nonlinear, that i affected by external factor. Solar irradiation, temperature and wind peed wa the main factor in the environment that affect PV [9]. Fig. 2. Equivalent Circuit of PV The ingle diode model Eq. ued to decribe the current output of the PV module I, i expreed by the following relationhip [9-11]: I I I I ph d p (1) Or q Vd AkTcN I I I ( e 1) ph V R d p (2) where I ph i the olar current, I d i the diode current, I i the diode revere aturation current, T c i cell temperature ( K), k i the Boltzmann contant (JK -1 ) and q i the electron charge (C), and R p and R in Ω are parallel and erie reitance. The output voltage equation of PV module i can be defined a: V V IR d (3) where V d i the diode voltage, and V i the output voltage of PV module. Change in the olar irradiation will caue a modification of a curve PV, while change in temperature will caue to hift in voltage and current output of PV. G I [ I K ( T T )] ph 1000 c i c r (4)

4 80 Refdinal Nazir et al. / Energy Procedia 68 ( 2015 ) qeg T Ak T T c c r I I e r T r (5) I r e I c qv oc AkT N c 1 (6) where G the i irradiation level, I c i the hort circuit current of PV, K i i the temperature contant, and T r i nominal temperature. The variation of output power P with the output voltage V for different level of olar irradiation i hown by Fig. 3. The maximum power point (MPP) for different level of olar radiation at 25 C for SHARP NDT060M1 module i alo preented in Fig. 3. Fig. 3. Variation of output power P with the output voltage V for different level of olar irradiation 2.3. The ingle phae inverter connected to utility grid The circuit equivalent and diagram phaor ofthe ingle phae inverter connected to the utility grid i hown in Fig. 4. V and V g are the output voltage of inverter and the grid voltage repectively. X L i the leakage reactance of tranformer and line. In thi model, the power factor for the power delivered to grid i aumed unity. A hown in Fig. 4b, The inverter mut generate the output voltage V, which phae angle hifted by α againt the grid voltage V g. a AC I X L b V DC DC V V g Utility Grid PV SPWM Inverter Fig. 4 Equivalent circuit and phaor of the ingle phae inverter connected to the utility grid (a) cicuit equivalent (b) diagram phaor.

5 Refdinal Nazir et al. / Energy Procedia 68 ( 2015 ) The complex power (S) dilevered to utility grid can defined a, S = V g I * = P + jq (7) Where, g I V V ji X L (8) 0 0 A indicated by Fig. 4b, V V 0, V V dan I I 0, then g g * 2 V VV VV V g g g g V S=Vg in j co j XL X L XL X I L (9) So, the active and reactive power (P and Q) can preented a, VV g P in (10) X L 2 VV g Vg Q co (11) X X L L where P i active power, Q i reactive power, V g i grid voltage, V i output voltage of inverter, X L i reactance of line and tranformer, δ i phaeangle betweenv andv g. Power Eq. (11 and 12) became the bai for calculating the optimal power to delivery from the PV ytem into the utility grid. 3. Modelling and imulation Theblock model of PV module i contructed baed on the equation of it equivalent circuit. PV generatorconit of 10 of SHARP NDT060M1 module, which are connected in erie. The parameter of 10 of SHARP NDT060M1module are given Table 1. Table 1. Parameter of SHARP NDT060M1 module [11] Parameter Symbol Min Typ. Unit Condition Open circuit voltage Voc V - Irradiance: 1,000 W/m2 Maximum power voltage Vpm V Short circuit current Ic A Maximum power current Ipm A Maximum power Pm W Module efficiency ήm % - Module temperature:25 C The parameter value in the model block uing the value in the data heet module, wherea a value of R and R p i calculated baed on the Eq. (2) and (3) that it reultare and 47.9.The modellig for block PV module i hown in Fig. 5. In thi figure, the ubblock ofcurrent ource and diode can be determined from Equation (4) and Equation (5).

6 82 Refdinal Nazir et al. / Energy Procedia 68 ( 2015 ) Fig. 5 The modelling of PV module block For modelling PV array, 10 PV module aembled in erie, o that it output voltage i 10 time of the output voltage of PV module and it output current will be remain the ame. A model of PV array connected with a model inverter and tranformer tep up 60/230 volt. The propoed model alo equipped DC capacitor to tabilize the input voltage of inverter and a filter inductor 2 mh to reduce the harmonic ditortion of inverter output. The Inverter i built from MOSFETS component uing SPWM method and the witching frequency of 10.8 khz. Overall, MATLAB SIMULINK-modelling of PV ytem connected to the utility grid i hown by Fig. 6. Fig. 6. Simulation model for PV ytem connected to utility grid. To analyze the power flow adjutment of the PV ytem connected to the utility grid, Eq. (10) and Eq. (11) can be ued. In thee Eq., two variable can be adapted by an inverter, namely index modulation (m a ) and phae angle (α). In thi analyi, m a and α can be olved through determination root of imultaneou Eq.(9) and Eq.(10).Here, the output voltage of the inverter can be completed a: V inv V dc 2 m a (12)

7 Refdinal Nazir et al. / Energy Procedia 68 ( 2015 ) If ratio of tranformer i a, then the relationhip between V inv and V can be expreed a: V inv V a (13) If Eq. (12) and (13) are ubtituted into Eq. (10) and (11) and the active and reactive power i et P = P max and Q = 0 repectively, then the following Eq. will be obtained a, Vdc 2 amv a g Gm ( a, ) Gi in Pmax 0 X l V 2 2 amv V dc a g g Hm ( a, ) Hi Co 0 X X l l (14) (15) In thi paper, the root olution of imultaneou Eq. (14 and 15) i calculated numerically uing Newton Raphon method, which i performed in in -function (NR Block). From thi olution, the value of m a and α can be determined. In thi analyi, V g or V pcc kept contant at a value of 200Volt and X L i Fig. 7 how the modelling ofnumerical calculation block. A hown thi figure, the numerical NR Block i ubtituted on the block that generating PWM ignal. Fig. 7. The modelling ofnumerical calculation block. Teting of the propoed ytem i done under condition of contant temperature and olar irradiation and load change. In addition, V pcc voltage i maintained at a contant value of 220 Volt. The variation of teting were elected baed on the PV ytem work for ome condition the output power. Thee variation are: Variation # 1 = Power Load < Output Power of PV ytem Variation # 2 = Power Load = Output Power of PV ytem Variation # 3 = Power Load < Output Power of PV ytem

8 84 Refdinal Nazir et al. / Energy Procedia 68 ( 2015 ) Fig. 8. Signal tet for variation of level irradiation 4. Reult and dicuion The imulation reult of power flow for PV ytem connected to the utility grid for different level of olar irradiation and load i hown by Table 3 or Fig. 9. A indicate in Tabel 3 or Fig. 9, the output power of PV ytem i proportional to it irradiation level. There are 3 variation of teting done. The firt variation, when the output power of PV ytem exceed the power load, then the utility grid will aborb the exce power from the PV ytem. The econd variation, if the output power of the PV ytem i equal to the load power, then there will be no delivery of power from the PV ytem to the grid. The third variation, when the output power of the PV ytem i not ufficient for the load power, then PV ytem and the grid will be hare to upply the load power. Table 3. Simulation reult for power flow of propoed ytem for different level of olar irradiation and load. Variation Irradiation (W/m2) Load Capacity Vpcc (Volt) Active Power (Watt) Reactive Power (VAr) PV Grid Load PV Grid Load # W 10VAr # W 20VAr # W 30VAr Fig. 9. Active and Reactive Power in PV, Grid, Load for different level irradiation and load. From the tet reult it can be hown that the propoed ytem can work well in optimizing the delivery of power from the PV ytem to the grid. The voltage at the PCC point obtained it table value approaching 220Volt.A hown in Table 3, the maximum value of the active power of the PV ytem for irradiation level of 1000

9 Refdinal Nazir et al. / Energy Procedia 68 ( 2015 ) Watt/m 2 wa obtained 408 Watt. Meanwhile, the maximum value of reactive power from the PV ytem ha produced Var. Thi value i till relatively low, becaue the value of the power factor of PV ytem i till high (0.9996).The wave form of voltage, current and power for variation # 1 i hown in Fig. 10. a b c Fig. 10 Wave form of voltage, current and power for variation # 1 (a) Utility Grid; (b) PV Sytem; (c) Load 5. Concluion The optimization of the power flow of the PV ytem connected to the ingle phae grid ha been uccefully imulated. Optimizing ha been done through the completion of the root of the active power equation P (ma, α) and reactive power equation Q (ma, α) uing Newton Raphon method. The voltage at the PCC point ha reached it table value at 220Volt. Simulation reult have hown the maximum value of the active power ytem at 1000 W/m2 irradiation wa 408 W, a the reactive power i needed only Var. Acknowledgement The author would like thank to Andala Univerity for the financial upport by BOPTN funding through univerity competitive reearch grant in 2014 (No. 05/UN.16/PL/D-UPT/2014). Reference [1] Van der Geer J, Hanraad JAJ, Lupton RA. The art of writing a cientific article. J SciCommun 2000;163:51-9. [2] StrunkJr W, White EB. The element of tyle. 3rd ed. New York: Macmillan; [3] Mettam GR, Adam LB.How to prepare an electronic verion of your article. In: Jone BS, Smith RZ, editor. Introduction to the electronic age. New York: E-Publihing Inc; p

10 86 Refdinal Nazir et al. / Energy Procedia 68 ( 2015 ) [1] C. Liu, B. Wu and R. Cheung, Advanced algorithm for mppt control of photovoltaic ytem, Proceeding on Canadian Solar Building Conference Montreal, Augut 20-24, 2004 [2] K. Chomuwan, P. Priuwanna, et al., Photovoltaic grid-connected inverter uing two-witch buckboot converter, in Conf. Rec IEEEPhotovoltaic Specialit Conf., pp , May [3] T. Noguchi, S. Togahi, et al., Short-current pulebaed maximum-power-point tracking method for multiple photovoltaic- and-converter module ytem, IEEE Tran. Ind. Electron., vol. 49, pp , Feb [4] Ratna Ika Putri & M. Rifa i, Maximum Power Point Tracking Control for PV Sytem Uing Neural Fuzzy, International Journal of Computer and Electrical Engineering Vol. 4, No. 1,, pp , February [5] Huijuan Li, Real and Reactive Power Control of a Three-Phae Single-Stage PV Sytem and PV Voltage Stability /12/2012 IEEE. [6] Tran Chong Binh, Active and Reactive Power Controllerfor Single-Phae Grid-Connected PV Sytem, [7] Ahmed A. A. Hafez, et. al., Simple Maximum Power Point Controller for Single-Phae Grid-Connected PV Sytem, Proceeding of the 14th International Middle Eat Power Sytem Conference (MEPCON 10), Cairo Univerity, Egypt, pp , December 19-21, [8] R. Nazir, et al., Renewable Energy Source Optimization: A Micro-Grid Model Deign, Energy Procedia, Vol. 52 (2014), pp [9] Mahmud, M. A., et al., Dynamic Stability of Three-Phae Grid-Connected Photovoltaic Sytem Uing Zero Dynamic Deign Approach. IEEE Journal Of Photovoltaic, Vol. 2, No. 4, October [10] J. Abdul., et al., Simulation on Maximum Power Point Tracking of the Photovoltaic Module uing LabVIEW, International Journal of Advanced Reearch in Electrical, Electronic and Intrumentation Engineering Vol. 1, Iue 3, September [11] Hernanz, J.A. Ramo, et al., Two Photovoltaic Cell Simulation Model In Matlab/Simulink, International Journal ontechnical and Phyical Problem of Engineering. Iue 10 Volume 4 Number 1, March 2012, pp [12] Kamtex Indutrie Pte Ltd., Nd-T060m1 Poly-Crytalline Silicon Photovoltaic Module With 60W Maximum Power