[pt] O fenômeno associado à estabilidade de tensão se caracteriza pela existência de valores máximos de potência ativa e reativa que podem ser transferidas a uma barra de carga, ou injetada na rede através dos geradores e compensadores síncronos. Sua relevância para o setor elétrico é constantemente reforçada pelo registro de ocorrências de colapsos de tensão em diversos países do mundo e, embora a instabilidade de tensão manifeste-se localmente, suas consequências se refletem na ampla deterioração do sistema. Impulsionado pelo crescente interesse a respeito dos métodos baseados em medições fasoriais sincronizadas para a detecção do máximo carregamento, este trabalho apresenta os principais modelos encontrados na literatura baseados em medições locais e no vasto monitoramento do sistema, com maior ênfase aos métodos de Corsi-Taranto e Circuito Acoplado de Porta-Simples Aprimorado (CAPS Aprimorado). Algumas contribuições são sugeridas ao modelo CAPS Aprimorado tendo em vista sua aplicação ao conjunto de barras de transferência e de geração. Explora-se a utilização dos equivalentes multi-portas como índice de avaliação das condições de estabilidade de tensão, comparando a identificação da barra crítica aos métodos da matriz D e dos autovalores e autovetores. São evidenciadas as principais limitações dos modelos mediante a um conjunto de análises estáticas e dinâmicas, considerando diferentes cenários de carregamento, a sensibilidade dos modelos ao ruído e a resposta dos métodos em face da atuação dos limitadores de sobre-excitação. / [en] The voltage stability phenomenon is characterized by the existence of a maximum active and reactive power that can be transferred to a load bus or injected into the network through the generators and synchronous compensators. Its relevance to the electric power sector is constantly reinforced by the record of occurrences of voltage collapses in several countries around the world. Although the voltage instability manifests itself locally, its consequences is reflected in the wide deterioration of the system. Driven by growing interest in methods based on synchronized phasor measurements for maximum loadability detection, this work presents the main models found in the literature based on local measurements and wide area monitoring, emphasizing the Corsi-Taranto method and Improved Coupled Single-Port Circuit (Improved CAPS). Some contributions are suggested to the Improved CAPS model considering its application to the set of transit and controlled buses. The use of the multi-port equivalents is explored as the evaluation index of voltage stability conditions, comparing the identification of the critical bus to the D matrix method and eigenvalues and eigenvalues method. The main limitations of the models are demonstrated through a static and dynamic studies, as well different loading scenarios, the sensitivity of the models to the noise and the response of the methods when the over-excitation limiters are considered.

Recent research has persistently emphasized that education is broken and that the solutions lie with technological resources in educational institutions and teaching methods (Teräs et al., 2020), which has generated a techno-solutionism approach of Edtech companies (Mirrlees & Alvi, 2019). The outbreak of COVID-19 exposed significant challenges and limitations when adapting education to the digital environment highlighting a need for a deeper understanding of the integration of technology with education. While some scholars focus on technological artefacts as an object of study at the intersection between neuroscience and technology (Healy, 1998), others focus on the importance of pedagogy and the challenges of researching pedagogy in a context of rapidly increasing technological advancement (Hellstén & Reid, 2008).Through investigating Brazilian teachers’ experiences and challenges of integrating technology within higher education before and during the pandemic, the study contributes to furthering understanding of the intersection between pedagogy and technology. The application of an exploratory sequential mixed-methods design contextualizes the teachers’ voices and enables contrast with the existing literature in international contexts. The study’s findings suggest that most of the teachers included technology in their classes to some extent. The teachers’ personal preferences and course discipline, however, can influence how they would incorporate technological resources in higher education. Moreover, the university’s policies and support structures also influence teachers’ decisions and motivations regarding technology integration. The study recontextualized the growing discussion in global research surrounding education and technology by using prominent scholars in the field to form a foundation through which to understand if similar issues may also appear in the Brazilian context. The main differences in the findings of this research set the case of Brazil apart in that the teachers noticed that the course discipline can be a factor in deciding whether or not to use technological resources in their classes at Brazilian institutions. The discussion about the course discipline did not appear in the international literature review focusing on technology-enhanced learning and teachers’ attitudes toward technology integrations. Moreover, this research facilitated the creation of the Inverted Mirror instrument, which was developed during the literature review process to create a visualization of comparisons. The Inverted Mirror instrument is used here to compare and visualize what is unseen or hidden during the comparison of teacher experiences in order to explain what occurs when technology is used in the classroom.