Power and compensation in systems with nonsinusoidal voltages and currents. Part 5: Reactance balancing of three-phase three-wire system with sinusoidal voltages and currents.

Abstract

Currents Physical Components (CPC)-Power Theory describes power properties of three-phase, three-wire systems in terms of three, mutually orthogonal currents: the active, reactive and unbalanced current. Unfortunately, only one of them, the active current, contributes to permanent flow of energy from the supply source to the load. The remaining two currents, the reactive current and the unbalanced current, are not only useless, but even harmful. Their presence contributes to an increase in the cost of energy delivery and degrades the supply quality of the distribution system. These currents can be reduced to some degree in the process of the system design, by balancing loads supplied from individual phases, and by adjusting the power of electrical motors to power of mechanical loads. When such measures are not sufficient, a balancing compensator can be installed. This paper presents fundamentals of the reactive and unbalanced currents compensation by means of reactance balancing compensators. Such compensation makes possible not only reduction of the supply current rms value, but also symmetrization of the supply current, which usually contributes to the reduction of the supply voltage asymmetry, thus to the supply quality improvement.

Keywords

Power Theory, reactance balancing compensators

Fig.

Bilbiography

[1] Czarnecki, L.S.: (2011) Moce i kompensacja w obwodach z niesinusoidalnymi przebiegami prądu i napięcia, Cz. 4, Składowe fizyczne prądu
w obwodach trójfazowych w warunkach sinusoidalnych. Automat yka , Elektr yka , Zakłócenia, www.elektro-innowacje.pl, Tom. 1, Nr. 4, str. 57-65.
[2] Czarnecki, L.S.: (2005) Moce w Obwodach Elektrycznych z Niesinusoidalnymi Przebiegami Prądów i Napięć, Oficyna Wydawnicza Politechniki Warszawskiej.
[3] Czarnecki, L.S.: (1995) Equivalent circuits of unbalanced loads supplied with symmetrical and asymmetrical voltage and their identification, Archiv fur Elektrotechnik, 78 pp. 165-168.
[4] Czarnecki, L.S., Hsu, M.S.: (1994) Thyristor controlled susceptances for balancing compensators operated under nonsinusoidal conditions,
Proceedings IEE, Part B, Electric Power Applications, Vol. 141, No. 4, pp. 177-185.
[5] Czarnecki, L.S., Hsu, M.S., Chen, G.: (1995) Adaptive balancing compensator, IEEE Transactions on Power Delivery, Vol. 10, No. 3, pp. 1663-1669.