DESIGN AND SIMULATION OF WIDE AREA MONITORING WITH SMART GRIDS USING PHASOR MEASUREMENT UNIT WITH DISTRIBUTED GENERATION

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1 DESIGN AND SIMULATION OF WIDE AREA MONITORING WITH SMART GRIDS USING PHASOR MEASUREMENT UNIT WITH DISTRIBUTED GENERATION 1 BEJJENKIDINESH, 2 PERUMANDLA SADANANDAM 1 MTECH, DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING, VAAGDEVI COLLEGE OF ENGINEERING 2 M.Tech,(PHD),MISTE,MIEEE, Associate professor DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING, VAAGDEVI COLLEGE OF ENGINEERING 1,2 U.G.C AUTONOMUS ACCREDIATED BY NATIONAL BOARD,CERTIFIED BY ISO 9001:2008 APPROVED BY AICTE &PERMANENT AFFILIATION JNTU,HYDERABAD BOLLIKUNTA,WARANGAL ,TELANGANA 1 bejjenkidinesh@rocketmail.com 2 sadi_p901@yahoo.co.in ABSTRACT In this paper, the modeling of a Phasor Measurement based Wide Area Monitoring and Control System was developed and presented. The proposed system emphasizes the need for monitoring and control of transmission lines connected to Distributed Energy Resources. In this work, the modeling for a complete scenario of a Discrete Fourier Transform based Synchronized Phasor Measurement Unit is presented. The performance of the developed Phasor Measurement Unit was evaluated by computing Total Vector Error and validated in accordance with IEEE C standard for synchrophasor measurements. The proposed system was simulated using MATLAB/Simulink environment and it is tested under two possible cases; normal operation and fault state. It was verified that the power system status can be easily monitored and controlled in real time by using the measured bus data. This improves the overall system reliability and avoids cascaded blackout during fault occurrence. For smart grid applications the simulation results confirm the validity of the proposed Phasor Measurement based Wide Area Monitoring System. 1. INTRODUCTION Electrical Power Transmission framework is the methods for transmitting power from producing station to various load focuses and power outages of such transmission systems directly affect the economy and security of a country. Subsequently there exists a requirement for changing Power Transmission Systems into programmed and self recuperating systems with correspondence framework. Difficulties because of framework dependability, maturing transmission foundation, increment in high entrance of inexhaustible and irregular dispersed age's clears path for Page No:571

2 Smart Transmission Grid. A portion of the exercises gained from significant Blackouts are absence of Wide Area View, Lack of Situational Awareness, Inaccurate and Inadequate System Models and Lack of Time Synchronized High Resolution Data. With the appearance of Synchrophasor estimations the above downsides can without much of a stretch be survived. Synchrophasor's otherwise called Synchronized Phasor Measurement Units are conveyed worldwide by utilities to screen and examine control framework conduct. Synchrophasor information comprises of constant estimations with a related exact time stamp. With exact time stamp these amounts are gathered from different areas, time adjusted, and after that handled as an intelligent informational collection. Be that as it may, observing and post occasion investigation were the main uses of synchrophasor before, without wide-territory correspondence where information was filed locally. Be that as it may, with new headways in Global Positioning frameworks, Synchrophasor's are presently utilized for remote observing and control applications, for example, Voltage Stability Assessment, Islanding Detection, Oscillation Monitoring and State Estimation. As of late, Real-Time Control (RTC) of the power lattice turned into a ground-breaking instrument that gives another perspective of intensity frameworks [2].This is accomplished by consolidating correspondence foundation with power framework layer while keeping up PMUs as a fundamental part in the system. The utilization of Phasor Measurement Units (PMUs) for Real-time Monitoring and control will enhance the execution of the framework, since estimations are progressively and are made accessible on the web. A summed up square chart of a Phasor Measurement Unit is appeared in Fig. 1.which fills in as the premise of reproducing such unit. Fig. 1. Block Diagram of Phasor Measurement Unit 2. SYSTEM DESCRIPTION The various components of a Synchrophasor based Wide Area Monitoring and Control Systems are discussed in this section. The system consists of a core power system layer, consisting of 50 kw generating station feeding power to load centers through Short Transmission Line situated at a distance of 10 km. Initially a Step up Transformer (208/11kV) is used to raise the operating voltage required for power transmission system. A Solar Photovoltaic system of 24 kw capacity is integrated into the power grid to cater the load requirements. Both the generating Page No:572

3 station (typically a Thermal Power Plant with Synchronous Generator) and the Photovoltaic Power Plant is used to manage the load on the power system network. Phasor Measurement units are being placed near the Generation Station, near the Photovoltaic Power Plant and on the load side for monitoring and control purpose. The information from the PMU are adjusted and designed to IEEE C organize before transmitted to the Phasor Data Concentrator [6]. The single line graph of the proposed Wide Area Monitoring System is appeared in Fig. 2 and the MATLAB/Simulink display is indicated Fig. 3. Fig.2. Single Line Diagram of the Proposed Wide Area Monitoring System Fig. 3. MATLAB Model of the Proposed Wide Area Monitoring System TABLE I - SYSTEM SPECIFICATION Page No:573

4 3. SMART GRID A smart grid delivers electricity from providers to purchasers utilizing advanced innovation with two-path correspondences to control apparatuses at customers' homes to spare vitality, decrease cost and increment unwavering quality and straightforwardness. It overlays the electrical network with a data and net metering framework. Such a modernized power arrange is being advanced by numerous administrations as a method for tending to vitality freedom, a worldwide temperature alteration and crisis versatility issues. Fig 4: smart grid The smart grid is made conceivable by applying detecting, estimation and control gadgets with two-path interchanges to power creation, transmission, dissemination and utilization parts of the power matrix that impart data about network condition to framework clients, administrators and computerized gadgets, making it conceivable to powerfully react to changes in lattice condition. A smart grid incorporates a smart observing framework that monitors all power streaming in the framework. It likewise fuses the utilization of superconductive transmission lines for less power misfortune, and additionally the capacity of coordinating sustainable power, for example, sunlight based and wind. At the point when control is minimum costly the client can enable the brilliant lattice to turn on chosen home apparatuses, for example, clothes washers or industrial facility forms that can keep running at subjective hours. At pinnacle times it could kill chosen machines to lessen request 4. PHASE LOCKED LOOP A stage bolted circle or stage bolt circle (PLL) is a control framework that attempts to produce a yield flag whose stage is identified with the period of the information "reference" flag. It is an electronic circuit comprising of a variable recurrence oscillator and a stage identifier that looks at the period of the flag got from the oscillator to an information flag. The flag from the stage indicator is utilized to control the oscillator in an input circle. The circuit Page No:574

5 thinks about the period of the info motion with the period of a flag got from its yield oscillator and modifies the recurrence of its oscillator to keep the stages coordinated. Recurrence is the subordinate of stage. Keeping the information and yield stage in bolt step suggests keeping the information and yield frequencies in bolt step. Therefore, a stage bolted circle can track an info recurrence, or it can produce a recurrence that is a various of the information recurrence. The previous property is utilized for demodulation, and the last property is utilized for backhanded recurrence combination. Stage bolted circles are generally utilized in radio, broadcast communications, PCs and other electronic applications. They may produce stable frequencies, recuperate a flag from an uproarious correspondence channel, or appropriate check timing beats in advanced rationale plans, for example, chip. Since a solitary incorporated circuit can give an entire stage bolted circle building obstruct, the system is generally utilized in present day electronic gadgets, with yield frequencies from a small amount of a hertz up to numerous gigahertz. 5. RESULTS AND DISCUSSION A Simulink demonstrate was created in Matlab to think about the execution of the proposed Wide Area Monitoring System for Smart Grid applications. The proposed show was created as per the dialog as specified in Section II. Table I demonstrates the estimations of the parameters utilized in the recreations. With the end goal to think about the WAMS framework execution, two sorts of tests are done. At first the framework is observed under sound state condition and afterward the framework is examined under focused or blamed state condition. A. Test under Normal Operating Conditions. In this test, the Phasor voltage and angle were monitored under steady state operating conditions. All three PMUs reported stable values within reference values. Fig.6 and Fig.7 shows the Phasor Magnitude and Phase angle recorded by PMU1 placed near the generating station. Fig. 5. Phasor Magnitude recorded by PMU1 placed near the Generating Station Page No:575

6 Fig. 6. Phasor Phase Angle recorded by PMU1 placed near the Generating Station Under normal operating state the voltage phasor magnitude and angle recorded through the Phasor Measurement unit (PMU2) placed near the Photovoltaic Plant shows a stable voltage generation. Fig.8 and Fig.9 shows the Phasor magnitude and Phase angle recorded by PMU2 placed near PV power plant. F Fig. 7.Phasor Magnitude recorded by PMU2 placed near the PV Plant Fig. 8.Phasor Phase Angle recorded by PMU2 placed near the PV Plant At the load side both the conventional generators and PV generators feed the load requirements. The system considered for this study is balanced loading conditions and the Phasor voltage magnitude and angle were strictly maintained within the limits. Fig.10 and Fig.11 shows the Phasor magnitude and phase angle recorded by PMU3 placed near Bus3. Page No:576

7 Fig. 9.Phasor Magnitude recorded by PMU3 placed near the load centre Fig. 10. Phasor Phase Angle Recorded by PMU3 placed near the load centre B. Test under Faulted State Conditions: In this test, a Three Phase Fault was created at Bus 2. The fault was simulated at 0.2 s and it was cleared at 0.5 s. PMUs 1 and 3 read no deviations in both angle and voltage magnitudes. It can be inferred that the fault is not located on those buses. Fig.12 and Fig.13 show the Phasor magnitude and phase angle recorded by PMU2 under fault conditions. In Fig.12 it can be observed that there exists a large dip in voltage from 0.2s to 0.5s which is mainly due to the fault present in the system. Fig. 11.Phasor Magnitude recorded by PMU2 during Fault Page No:577

8 Fig. 12. Phasor Phase Angle recorded by PMU2 during Fault C. Phase Angle Comparison: Fig.14 shows PMU2 Phase angle values compared with reference values under normal operating condition. Under steady state conditions the phase differences are smaller and hence it can be inferred that, the power system network is under stable operating state. During faulted condition, it can be inferred that the phase angle difference values between the measurements recorded at PV plant and the reference bus was found to be very large and typically greater than 30 degrees which confirms that the power system is under stressed condition. Fig. 13.Phase Angle Difference Recorded by PMU2 under Normal State Fig.15 shows PMU2 Phase angle values compared with reference values under faulted conditions. Here the phase difference is very large during 0.2s to 0.5s intervals and hence it can be inferred that the power system is under stressed condition. Page No:578

9 ] Fig. 14.Phase Angle Difference Recorded by PMU2 under Fault State D. Synchrophasor Measurement Evaluation: The hypothetical estimations of a Synchrophasor portrayal of a sinusoid amount and the qualities acquired from a Phasor Measurement Unit may incorporate contrasts in both adequacy and stage edge. IEEE C standard on synchrophasor portrays the quantum of blunder permitted in Phasor Estimation and it is characterized by a factor called Total Vector Error (TVE). TVE is characterized in Equation (5) Where, Xr(n) and Xi(n) are the succession of appraisals given by the unit under test, Xr(n) and Xi(n) are the arrangements of hypothetical estimations of the info motion at the moments of time (n) alloted by the unit to those qualities. Table II, depicts the estimation prerequisites according to IEEE C standard for enduring state conditions test. TABLE II SYNCHROPHASOR MEASUREMENT REQUIREMENTS Nominal Frequency Testing: For Nominal Frequency testing, the frequencies of the test signals are kept consistent at the ostensible recurrence scope of 50 Hz. Every other parameter of the flag are kept at ostensible conditions. TVE Page No:579

10 acquired is inside the standard furthest reaches of 1%. Fig. 16 portrays the TVE plot under ostensible recurrence conditions. Fig. 15. TVE Plot for PMU under Nominal Frequency Condition Off-Nominal Frequency Testing: For Off-Nominal Frequency testing, the frequencies of the test signals have to be varied around the nominal frequency by ±5 Hz. All other parameters of the signal are kept at nominal conditions. Here also TVE obtained is within the standard limit of 1%. Fig. 17 shows the TVE plot under off-nominal frequency conditions. Fig.16. TVE Plot for PMU under Off-Nominal Frequency Condition E. Harmonic Distortion Testing: For signal under Harmonic Distortion testing, the standard requires signals with 10% harmonic and up to 50th harmonic. But only test signals with 10% of the 3rd and 5th harmonic have been generated. It can be observed that TVE obtained for PMU is within the standard limit of 1%. Fig. 18 shows the TVE plot for PMU under harmonic distortion conditions. Fig. 17. TVE Plot for PMU under Harmonic Distortion Condition Page No:580

11 6. CONCLUSION A performance analysis for a Phasor Measurement Unit based Wide Area Monitoring and Control System was carried out in MATLAB/Simulink environment. The developed system was tested under two conditions namely: Steady state and Faulted state conditions. Under steady state conditions the Phasor measurements from Simulated PMU s placed at generating station bus and at the PV plant showed measurements well within the stipulated operating conditions. Under faulted state, the Phasor measurements recorded by the PMU placed near the PV plant showed larger phase angle difference with reference to the reference phasor. Also a large voltage dip near the Photovoltaic bus is also seen Hence control signals were created dependent on the information got from the PMU2 to PDC and thus, this zone was segregated by means of dynamic control signs to the electrical switch, before spreading to different parts of the power framework arrange. Moreover, the reenacted synchrophasor is additionally approved for IEEE C synchrophasor standard for power framework arrange. All outcomes got affirm the adequacy of the grew Wide Area Monitoring System arrange for keen network applications. REFERENCES [1]. AJ.DeLaRee, V.Centeno,J.S.ThorpandA.G.Phadke,"SynchronizedPhasorMeasurementApplicationsinPower Systems," inieeetransactionsonsmartgrid,vol.1,no.1, pp.20-27,june2010. [2]. V.C.Gungor,D.Sahin,T.KocakandS.Ergut,"ASurveyonSmartGridPotentialApplicationsandCommunicationRequ irements,"inieeetransactionsonindustrialinformatics,vol.9,no.1,pp.28-42,feb [3]. V.Terzija,G.Valverde,D.CaiandP.Regulski.,"Wide-AreaMonitoring,Protection,andControlofFutureElectric PowerNetworks,"inProceedingsoftheIEEE,vol.99,no.1,pp.80-93,Jan [4]. Bose, SmartTransmissionGridApplicationsandtheirSupportingInfrastructure IEEETransactionsonSmartGrid, vol.1,issue1,pp.11-19,2010. [5]. Venkatasubramanian,X.Yue,G.Liu,M.SherwoodandQ.Zhang, WideAreaMonitoringandControlAlgorithmsfor LargePowerSystemsusingSynchrophasors InternationalConferenceonPowerSystem,2009. [6]. K.E.Martin,"SynchrophasorMeasurementsUndertheIEEEStandardC WithAmendmentC a, " inieeetransactionsonpowerdelivery,vol.30,no.3,pp ,june [7]. M.G.Villalva,J.R.Gazoli,andE.Ruppert, ModelingandCircuitbasedSimulationofPhotovoltaicArrays,Brazilian JournalofPowerelectronics.Vol.14,no.1 pp.35-45,february2009. [8]. N.PandiarajanandRanganathMuthu, MathematicalModelingofPhotovoltaicmodulewithSimulink,Proceedings oftheinternationalconferenceonelectricalenergysystems,pp.314,3-5jan2011. [9]. SynchronizedPhasorMeasurementsandtheirApplications bya.g.phadkeandj.s.thorpisbn Page No:581