Desenvolvimento de uma nova ferramenta para análise de estabilidade de tensão no software PSP-UFU: uma plataforma gratuita e de código aberto para estudos de sistemas de potência

Abstract

In recent years, several voltage stability indices have been developed and implemented in simulation programs with the aim of helping the analysis of the voltage instability problem of electrical power systems, resulting in the creation of new computational tools capable of improving the system planning and operation. Following this proposal, the present work aims to implement three voltage stability indices within the PSP-UFU software (a free and open-source software that performs studies of transient and dynamic stability, power flow, short-circuit calculation and harmonic) and verify their performance, when submitted to dynamic analysis. The study is applied to two cases, the first is a reduced 3-bus radial system and the second the 14-bus IEEE system. The tests are carried out through successive increments of load on a given bus until its voltage becomes unstable. Tests were performed considering different types of loads: constant power, constant impedance and mixed composition (40% constant impedance and 60% constant power). In the second case, the behavior of the indices with and without the action of AVRs was studied. All indices proved to be promising, because their sensitive values decreased as the system tended to instability. In the second case, the indicators were also able to show that voltage collapse is delayed when using AVRs. It is noteworthy that the first indicator, 𝑉𝑆𝐼1𝑖=Δ𝑉𝑖/Δ𝑄𝑐𝑖, presented greater sensitivity, detecting small increments of load, however, the third indicator, 𝑉𝑆𝐼3𝑖=Δ𝑉𝑖/Δ𝑆𝑐𝑖, has the advantage of contemplating two extreme situations: load increments whose powers are purely active or purely reactive. In contrast, indicators 1 (𝑉𝑆𝐼1𝑖=Δ𝑉𝑖/Δ𝑄𝑐𝑖) and 2 (𝑉𝑆𝐼2𝑖=Δ𝑉𝑖/ΔP𝑐𝑖) can be applied to only one of these two situations.