Application of active power sensitivity to frequency and voltage variationson load s
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26102010, 05:48 PM
Application of active power sensitivity to frequency and voltage variationson load shedding Presented by Ejas Kunhalan P.E. S7 E1 College Of Engineering, Trivandrum 200711 batch Application of active power sensitivity to frequency and voltage variations on load shedding.pptx (Size: 352.29 KB / Downloads: 77) Overview: Objectives Continued Introduction Frequency and voltage measurement techniques Active power sensitivity to frequency and voltage variations Testing Conclusions Future works OBJECTIVES A unique load shedding scheme that combines frequency, voltage, rate of change of frequency and rate of change of voltage to shed an optimal amount of load at suitable locations whenever there occurs a power system blackout. Ways used to achieve this Goals To use the rate of change of frequency to find the amount of load to shed To use the voltage variation to identify the appropriate buses for load shedding Introduction Present day power system Chances for power system failures Emergency method to avoid the power system failure Continuation Traditional method. Limitations of the above It focus just on one parameter, either frequency or voltage It relied on just the level of frequency or voltage and ignored the rate of change of these parameters Frequency and voltage measurement techniques Measured by devices like relays,PMU’s etc Phasor measurements units are the new technique which synchronizes with new GPS technology Synchrophasors devices are used which is already present in the system Different other methods In absence of above sophisticated devices the following methods are used: From the voltage waveforms by different Mathematical methods like Fourier analysis etc. A two stage Kalman Filter KALMAN FILTER The first stage of this technique is an extended Kalman Filter Next stage is a linear Kalman filter Active power sensitivity to frequency and voltage variations The most basic equation of motion for a Machine is given by Inertia Constant is defined as Continuation Equivalent inertia constant is as follows Substituting H in place of J in the basic equation of motion , we get But we know that Next task is to identify the appropriate buses for load shedding Buses are Ranked The buses with the steepest rate of voltage decline can be selected as the first appropriate Bus Continuation Division of load shedding in critical buses is based on the sensitivity of change in injected power with voltage Now the Real power injected to the buses are given by Along with losing Real Power, proportional amount of Reactive power is lost And it is given by the following equation Main time consuming parts of this power system disturbance restore are as follows Delays in measurement Time taken for online computation of the load shedding amount The delay in sending control signals to breakers on feeders to open and shed load Now a days it is Practically possible to allow 0.1sec between subsequent load sheds Testing the proposed application Testing is done on an IEEE 30 bus system It consists of 6 generators,41 lines and about 190MW Now the variations of frequency and voltages while testing the proposed applications are shown below: VARIATION OF FREQUENCY BEFORE IMPLEMENTING SCHEME Conclusion Preliminary results of load shedding based on the described principles show that: The rate of change of frequency can estimate the magnitude of disturbance accurately The rate of change of voltage can identify the location for load shedding Use Search at http://topicideas.net/search.php wisely To Get Information About Project Topic and Seminar ideas with report/source code along pdf and ppt presenaion



