Abstract
Metal-oxide arresters (MOAs) are used to absorb the electrical energy resulting from overvoltages in power systems. However, temperature rises caused by the absorbed energy can lead to the electrothermal failure of MOAs. Therefore, it is necessary to analyze the electric and thermal characteristics of MOAs. In this paper, in order to study the electric and thermal characteristics of MOAs under power frequency voltage, an improved electrothermal model of an MOA is presented. The proposed electrothermal model can be divided into an electric model and a thermal model. In the electric model, based on the conventional MOA electric circuit, the effect of temperature on the voltage–current (V–I) characteristics of an MOA has been obtained. Using temperature and applied voltage as input data, the current flows through the MOA can be calculated using the artificial neural network (ANN) method. In the thermal model, the thermal circuit of a MOA has been built. The varistor power loss obtained from the electric model is used as input data, and the temperature of the zinc oxide varistors can be calculated. Therefore, compared with the existing MOA models, the interaction of leakage current and temperature can be considered in the proposed model. Finally, experimental validations have been done, and the electrothermal characteristics of an MOA have been studied by simulation and experimental methods. The electrothermal model proposed in this paper can assist with the prediction of the electric and thermal characteristics of MOAs.
Highlights
Metal-oxide arresters (MOAs) are electric equipment that are used in the power systems for protection against overvoltages [1,2]
What’s more, when an AC voltage is applied to a MOA, the resistive current flowing through the zinc oxide (ZnO) varistors can cause power loss, which may lead to temperature rise or thermal failure of the MOA [12,13,14,15]
Compared with the existing studies, the electrothermal model proposed in this paper has considered the interaction of resistive current and the temperature rise of MOA; it can simulate the electric and thermal characteristics at the same time
Summary
Metal-oxide arresters (MOAs) are electric equipment that are used in the power systems for protection against overvoltages [1,2]. What’s more, when an AC voltage is applied to a MOA, the resistive current flowing through the ZnO varistors can cause power loss, which may lead to temperature rise or thermal failure of the MOA [12,13,14,15]. Seyyedbarzegar [27] built a thermal balance diagram, and it has been confirmed that the power loss caused by the leakage current is dependent on the applied voltage, temperature, and V–I characteristics of the varistors. Compared with the existing studies, the electrothermal model proposed in this paper has considered the interaction of resistive current and the temperature rise of MOA; it can simulate the electric and thermal characteristics at the same time. Using temperature and applied voltage as input data, the leakage current flowing through the varistors can be obtained, and the electric part of the electrothermal model has been validated through experimental results. The electrothermal simulation reaches a steady state, the simulation process reaches simulation time reaches the end, or the electrothermal simulation reaches a steady state, the the end. process reaches the end
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