The Kalman Filter in Power Quality – Theory and Applications


== Abstract ==

Power quality is a topic in the area of engineering that emerged by the 1970 decade. It is a field that has attracted special interest recently due to the continuous industrial growth, to the raise of power demands, and to the proliferation of âpollutingâ electrical loads. One of the objectives of power quality is to meet a clean sinusoidal, stable, reliable, regulated, and uninterrupted supply voltage in electrical systems, in order to feed the so-called critical loads. A critical load is such an equipment that, if it fails or works inadequately, it can cause very high losses, being economical, or of any class; and a low quality supply can cause this situation. For example, it can cause the loss of vital information, interruption of an expensive industrial process, poor quality or damage to products; interruption of important communications as air traffic control, security units, and financial information; permanent damage to equipments, and even put lives in danger at hospitals. The great increment in critical processes has led to the requirement of assuring a high quality and safe power supply in many medical, communications, and industrial procedures, with the aim of feeding machinery and automatic systems that perform diverse important tasks. A safe protection of the operations is the objective. Problems and failures in electrical loads can be caused by some of the disturbances that exist in electrical systems. Among them are: harmonic distortion, unbalances, non characteristic harmonics, sags, swells, short and long interruptions, flicker, and short circuits. The disturbances that more affect critical loads, specially the industrial kind, are the sags, the swells, and the interruptions. The sag is defined as a 10% to 90% decrement of the nominal value of voltage, which can last from a half cycle to one minute. The swell is defined in a similar way, but represented by the 10% to 80% increase of the nominal value (IEEE Std 1159-1995, 1995), (IEEE Std 1159.3-2003, 2004). Sags have been identified as the most severe disturbance, and as the one that more causes damages and problems to facilities and equipments. It is considered that sags, together with momentary interruptions, are responsible of the 92% of power quality problems that face typical industrial consumers (Bhadkamkar et al., 2003). Sags can be caused by atmospheric discharges, short circuits, energizing of motors and high power loads, operation of soldering machines, and arc furnaces, to mention some. The swells can be caused by disconnections of high power loads from the grid. As can be noted, the disturbances can be generated by natural cause, by neighbor installations, or by accident. It is always desirable their


== Original document ==

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* [https://cdn.intechweb.org/pdfs/10897.pdf https://cdn.intechweb.org/pdfs/10897.pdf],
: [https://www.intechopen.com/books/kalman-filter/the-kalman-filter-in-power-quality-theory-and-applications https://www.intechopen.com/books/kalman-filter/the-kalman-filter-in-power-quality-theory-and-applications],
: [https://cdn.intechopen.com/pdfs/10897/InTech-The_kalman_filter_in_power_quality_theory_and_applications.pdf https://cdn.intechopen.com/pdfs/10897/InTech-The_kalman_filter_in_power_quality_theory_and_applications.pdf],
: [http://cdn.intechweb.org/pdfs/10897.pdf http://cdn.intechweb.org/pdfs/10897.pdf],
: [https://academic.microsoft.com/#/detail/1511733854 https://academic.microsoft.com/#/detail/1511733854]

* [https://www.intechopen.com/download/pdf/10897 https://www.intechopen.com/download/pdf/10897],
: [http://dx.doi.org/10.5772/9582 http://dx.doi.org/10.5772/9582]