Impact of FACTS Devices in Automatic Generation Control of a Deregulated Power System Kamlesh Pandey Research Scholar, AKTU, Lucknow Assistant Professor, Department of EEE, Amity University Uttar Pradesh, 201313 S. K. Sinha Professor, Department of EEE, Amity University Uttar Pradesh, 201313 Abstract - In this paper, the impact of integration of FACTS devices viz. TCPS and TCSC on Automatic Generation Control (AGC) of a two area thermal-thermal deregulated power system have been studied in order to enhance the performance of responses such as frequency deviation and oscillation damping, deviation of tie line power between the areas and power generated by GENCOs. The comparison of results between those obtained with inclusion and exclusion FACTS devices in the system has been shown using simulations. Keywords - AGC, Thyristor Controlled Phase Shifter, Thyristor Controlled Series Compensator, Tie Line, Deregulated Power System. NOMENCLATURE aij = Area capacity ratio bi = Frequency bias f = Rated frequency Δf i = Frequency Deviation Kp = Gain of generator -load system ¨Pg = GENCO’s incremental power generation ¨Ptie = Deviation in tie-line power between areas R = Speed regulation of governor Tt = Time constant of turbine Tp = Time constant of generator-load system Tg = Time constant of governor I. INTRODUCTION Controllability of transmission systems such as stabilization of system frequency and tie line power deviations when load changes is a big challenge today. With restructuring in progress the transmission systems are were subjected to may changes in different countries. Thus, there is necessity of flexibility that transmission systems gets adapted to these changes more quickly and act accordingly depending on available distinct generation and diferent patterns of load . FACTS technology 978-1-5090-4530-3/16/$31.00 ©2016 IEEE Ashish Shrivastava Professor, Department of EE, JSSATE, Noida, Uttar Pradesh201301 responds to such needs and were used in improvement of power transfer and controling capability of the system resulting in improvement of system performance particularly in the case of transient response oscillation damping. FACTS devices and their utilization in AGC has been researched and further advancements were suggested by several researchers [2-5]. Our work depicts simulation of AGC with fuzzy controler along with FACTS devices carried out in MATLAB. The simulation damps out oscillations of frequency and tie line power transient responses in a thermal-thermal deregulated power system. Experiments were carrie dout to establish that AGC accomplishes improvement when Intelligent devices works in tandem with FACTS devices.Two types of FACTS devices viz. Thyristor controlled phase shifter (TCPS) and Static synchronous series compensator (TCSC) were appropriated in this study for performance improvement mainly in oscillation damping in the AGC proceedings. Knowledge based techniques along with FACTS devices which resulted in transient responses were compared with those outcomes obtained when controller used is of conventional integral type under various conditions and constraints with and without FACTS devices. II. THYRISTOR CONTROLLED PHASE SHIFTER Thyristor Controlled phase Shifter (TCPS) lowers the oscillations frequency of the system for this it changes the phase angle of the system. Fig 1. Shows the two respective areas of the TCPS connnection with the system. The power system model provides the flow of power in tie line of the two area system ΔPtie12 which is given by : VV ΔPtie12 = 1 2 cos(δ1 − δ 2 + φ )(Δδ1 − Δδ 2 + φ ) (1) X 12 equipped with TCSC is obtained as P= Fig. 1. Taking synchronizing power T12 as: δ1 = 2π ³ Δf1dt and k= and δ 2 = 2π ³ Δf 2 dt Using laplace transform of equation (1) and K ϕ ( s ) = ϕ ΔError 1 + Tϕ Where, ¨Error= ¨F1(s) 2π Kϕ s 1 + Tϕ ΔPtie12 ( s ) = T12 (ΔF1 ( s ) − ΔF2 ( s )) + T12 X ij (1 − k ) sin (δ ij ) where, k is the TCSC compensation level given by TCPS in two area system VV T12 = 1 2 cos(δ1 − δ 2 + ϕ ) X 12 ViV j X TCSC X ij (2) The equivalent reactance of TCSC is given as (3) X TCSC = ΔF1 ( s ) (4) III. THYRISTOR CONTROLLED SERIES COMPENSATOR (TCSC) TCSC regulates the real power flow andr the current magnitude of a transmission line. This is done by varying the series reactance of TCSC. TCSC consists of a capacitor in parallel with a thyristor controlled reactor.. Series compensation is very effective in increasing the capability of power transfer and stability. Hence, the TCSC has been used to improve AGC of the power system. The real power flow through the transmission line X C X L (α ) X C − X L (α ) XL is reactance and Į is the thyristor firing angle. Fig. 2. TCSC in two area system IV. CASE STUDY: TWO THERMAL AREAS DEREGULATED POWER SYSTEM A deregulated power system having two inter-connneted areas along with TCPS cascaded with the tie line is Fig. 4. Two area system with a FACTS Device 0.03 0.02 0.01 V. RESULTS AND DISCUSSIONS Two different scenarios were simulated and the obtained results were compared. Case(i): FACTS devices were not connected in the system and system is simulated Case(ii): FACTS devices of only one type i.e. either TCPS or TCSC is connected at a time and system is run. The deregulated power system model has been simulated in MATLAB for two different situations. Firstly, none of the FACTS devices have been connected and the model has been run with integral controller. Secondly, TCPS and TCSC devices have been connected one by one and model has been run in each case. The results obtained from the simulation of the power system model with and without FACTS (TCPS and TCSC) have been plotted and shown in Fig 3 and Fig 5-Fig 10.From the figures it can be easily inferred that both the FACTS devices help in fast oscillation damping and peak value reduction. Settling time is also reduced when either of TCPS or TCSC is included in the model. In Fig. 3 and Fig 5, where the change in frequency in area 1 and area 2 respectively have been compared with and without FACTS devices, it can be inferred that there is sharp reduction in frequency oscillation damping and significantly small settling time. Fig. 6 is plot of deviation in tie line power in the presence and absence of FACTS devices. Here also -0.02 -0.03 delf1 delf1TCPS delf1TCSC -0.05 -0.06 0 5 10 15 Time (Sec) 0.25 0.0 0.30 º 0.25 0.0 0.0 »» 0.25 1.0 0.7 » » 0.25 0.0 0.0 ¼ Fig. 3 Response of del f1 0.04 0.03 0.02 del f Area 2 (Hz) As per the DPM matrix each DISCOM demands 0.02 pu MW power from GENCO. With refernce to the given area participation factors apf1,apf2,apf3 and apf4 are 0.75, 0.25, 0.50 and 0.50 respectively. GENCOs participate in AGC. The loads which are not contracted have been assumed to be zero. 0 -0.01 -0.04 0.01 0 -0.01 -0.02 -0.03 delf2 delf2TCPS delf2TCSC -0.04 -0.05 0 5 10 15 Time (Sec) Fig. 5 Response of del f2 -3 10 x 10 delptie delptieTCPS delptieTCSC 8 del ptie (pu MW) ª 0.5 «0.20 DPM = « « 0.0 « ¬0.30 similar kind of results is obtained. del f Area 1 (Hz) depicted in Fig: 4 Different types of loads stipulated by a distribution company are treated as local loads. UCL1, UCL2, UCL3, and UCL4 are un-contracted loads. The loads stipulated by a Distribution Company k is notationed cpfjk which depicts contracted load fraction by the company k from a Generation Company j. Information are sent through these signals about a Genco following a stipulated load of a distribution company . By applying the below constraints the simulation of AGC of subjected deregulated power system (thermal-thermal) were carried out. Distribution Companies contract with the Generation companies in accordance with the following Disco Participation Matrix: 6 4 2 0 -2 0 5 10 15 Time (Sec) Fig 6 Response of del Ptie Figs. 7 to 10 show the power generated by the GENCO 1, 2, 3 and 4 respectively. The graphical values and computed values of generated power give almost identical values. In Fig. 7 to Fig. 10, the incremetal power generated by four GENCOs have been shown and compared for the above cases. It is evident from the plots that there are distinct improvement in the performance when either of TCPS and TCSC is included in the system,. In all these plots oscillations damping and peak overshoots have reduced when the FACTS devices are included in the system. Comparing different FACTS devices, TCSC gives better results than TCPS for this system. = 0.021 puMW ΔPg 2 = 0.20 × 0.02 + 0.25 × 0.02 + 0.0 + 0.0 = 0.009 puMW ΔPg 3 = 0.0 × 0.02 + 0.25 × 0.02 + 1.0 × 0.02 + 0.7 × 0.02 0.04 delpg1 delpg1TCPS delpg1TCSC 0.035 The incremental generated power by GENCOs are as follows: ΔPg1 = 0.5 × 0.02 + 0.25 × 0.02 + 0.0 + 0.3 × 0.02 = 0.039 puMW ΔPg 4 = 0.3 × 0.02 + 0.25 × 0.02 + 0.0 + 0.0 del pg1 (pu MW) 0.03 X: 13.45 Y: 0.02111 0.025 = 0.011 puMW 0.02 0.025 0.015 0.01 delpg4 delpg4TCPS delpg4TCSC 0.02 0 0 5 10 15 Time (Sec) Fig 7 Response of del Pg1 delpg4 (pu MW) 0.005 0.015 0.01 X: 13.45 Y: 0.01108 0.025 0.005 delpg2 delpg2TCPS delpg2TCSC 0.02 0 0 5 10 15 d e l p g 2 (p u M W ) Time (Sec) Fig 10 Response of del Pg4 0.015 X: 12.55 Y: 0.008878 0.01 0.005 0 0 5 10 15 Time (Sec) Fig 8 Response of del Pg2 0.05 d e l p g 3 (p u M W ) 0.04 X: 13.19 Y: 0.03908 VI. CONCLUSIONS FACTS devices and their applications were simulated and the results in a deregulated power system(thermalthermal) were depicted throughout the research. It is also observed that FACTS devices incorporated with Knowledge based systems like Fuzzy controllers very effectively damp out frequency changes and deviations, tie-line power exchange and oscillations in power generated. The results also depict peak deviation reduction on either side of zero. It is also observed that the settling time also reduces in different scenarios. Better results are obtained when FACTS devices are incorpoated with Intelligent controllers as compared to the results attained using conventional integral control. 0.03 f = 60 Hz Tg = 0.08 sec 0.02 delpg3 delpg3TCPS delpg3TCSC 0.01 0 0 5 10 Time (Sec) Fig 9 Response of del Pg3 R = 2.4 Hz/p.u. MW Tt = 0.3 sec b= D+1/R = 0.425 H= 5 sec Kps = 120 Pr1 = Pr2 =2000 MW 15 D= 8.33*10-3 p.u. MW/ Hz Ptie, max = 200 MW Tps=20 sec REFERENCES  Narain G. 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