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TU Delft Faculty of Electrical Engineering, Mathematics, and Computer Science Circuits and Systems Group EE4C03 STATISTICAL DIGITAL SIGNAL PROCESSING ASSIGNMENT Estimation algorithm for a Phasor Measurement Unit 1. Context The incorporation of renewable energy sources into the power grid leads to uncontrolled changes in the system input and load. Real time monitoring and control is required to balance the system and maintain the required voltage level and line frequency (50 Hz). In the mid-1980s the synchronised Phasor Measurement Unit (PMU) was introduced. A PMU estimates the power system voltage and current phasor (angle and magnitude), frequency and rate of change of frequency (ROCOF), and sends time-stamped measurement data to a central location [1]. The IEEE Standard C37.118.1 (2011) and its Amendment (2014) defines the PMU output and accuracy requirements for both static and dynamic conditions [2]. One of the main operations of a PMU is the high frequency sampling of voltage and current analog input signals and the calculation of its time-synchronized phasors. The voltage signal is of the form x(t) = A(t) cos(2πf0 (1 + 1 )t + 2 ) + 3 In fact, actual 3-phase systems have 3 such signals which are tightly synchronized. Under steady-state conditions, estimating the phasors is straightforward (e.g. using the DFT), but this is different under dynamic conditions. 2. Problem Given the model of the voltage signal, find a suitable estimation algorithm for the instantaneous synchronized phasors. The implementation may be recursive or adaptive (RLS, Kalman). The algorithm has to be modeled in matlab. The objective is change detection: what is the earliest moment you can reliably detect that the frequency has changed from its nominal setting (50 Hz)? 3. Assignment In a group of 2 students, write a compact essay where you briefly present the problem, consider a suitable model and a performance measure, develop an (adaptive) model identification algorithm, and test this on example data. Include your matlab code as an appendix. The essay typically has 4–10 pages (except for the appendix) depending on the number of graphs. 4. Hints Conduct a brief literature study to orient yourself on this problem. The paper [2] contains a description of a measurement setup and several classes of faulty signals. A data set with PMU synthetic test measurements (simulated data) is available from dipl.ing. Matija Naglic. This dataset consists of a sequence of events that you can use to develop your algorithms. Your algorithm will be tested on another data set where the objective is to detect and classify dynamic events (line trip, generator trip, load shedding, oscillation) as early as possible. 5. Consultants Dipl.-ing. Matija Naglic Intelligent Electric Power Grids Email: [email protected] Tel: +31 15 27 88007 Room: LB 03.210 Dr. Marjan Popov Tel: +31 15 27 86219 Email: [email protected] Room: LB 03.250 6. Course contact person Prof.dr.ir. Alle-Jan van der Veen Email: [email protected] Room: HB 17.040 References [1] K.E. Martin e.a., “Exploring the IEEE standard C37.118-2005 synchrophasors for power systems,” IEEE Tr. Power Delivery, vol. 23, pp. 1805–1811, Oct 2008. [2] Nhi T.A. Nguyen, M. Popov, and G. Rietveld, “Phasor measurement unit testing in accordance with the IEEE C37.118.2011.1-2011 synchrophasor standard,” IPSI BgD Transactions on Internet Research, vol. 11, July 2015. ISSN 1820-4503. 2