Analiza dokładności przetwarzania sygnału w torze pomiarowym cyfrowego terminalu automatyki elektroenergetycznej - wybrane wyniki badań

W artykule zostaną przedstawione wyniki badań układów wejściowych wybranego zabezpieczenia cyfrowego. Przeprowadzona zostanie wstępna analiza poprawności ich pracy w przypadku sygnałów wejściowych w postaci mono- i poliharmonicznych sygnałów napięciowych i prądowych o zmiennej amplitudzie i częstotliwości. Badany układ toru przetwarzania analogowo-cyfrowego zabezpieczenia elektroenergetycznego wykazuje dobre właściwości pomiarowe zarówno dla sygnałów prądowych jak i napięciowych.

Today's digital technology makes it possible to construct power system protection devices characterized by the so-called open architecture. It assumes that such devices can easily adapt their hardware and software functions to the automation tasks of different power system objects. Additionally, these units, owing to strong teleinformatic interconnections, enable using the common databases (knowledge bases) about the object and its environment (Fig. 2). As far as the decision-making is concerned, there has been observed the rapid growth in development of adaptive techniques (both configurational and frequencional adaptation) as well as multicticriterial decision-making lately. Increase in the processing power of protection system elementary units and availability of access to the data and information about the object and its environment lead to the possibility of using unconventional decision-making structures, i.e. artificial neural networks, fuzzy logic and dispersed algorithms. Therefore, it seems that a major factor influencing the "quality" of decisions made by protection devices is the reliable measurement data and input information obtained mainly from the so-called digital signal processing chain of the elementary unit in a protection system which, additionally, have to be achieved under strict time limitations. The paper presents investigation results concerning input units of a selected digital power protection device verifying the accuracy of the mentioned units in the case of monoharmonic and poliharmonic current and voltage signals of varying amplitudes and frequencies. The tests performed show that the measurement input chain of the digital protection device has good measurement properties for both current and voltage signals. Some results of the voltage input properties for high voltage (above the rated one) restrict the possible application of such devices to the protections that make decisions on the basis of undervoltage and overcurrent criteria or their combinations.