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Summary: This article presents an adaptive voltage sag compensation scheme by using interline bridge‐type fault current limiter (IBFCL) in radial distribution network to protect customers connected to the point of common coupling (PCC). Regarding voltage sag depth, the IBFCL provides a variable resistor in faulted feeder to compensate the PCC voltage at the acceptable level under whole voltage sag condition. To achieve this, a new control system based on the deviation of voltage sag at PCC bus is designed and implemented to the IBFCL. To check the effectiveness of the IBFCL for voltage sag compensation, extensive time domain simulations are performed under both symmetrical and asymmetrical fault conditions on the distribution system in professional's simulation tool for analyzing power systems transients (PSCAD)/electromagnetic transients including DC (EMTDC) environment. Also, its performance and control system are compared to the conventional BFCL and transformer‐type solid‐state fault current limiter (TSSFCL). The simulation results show that by using only one limiting resistor in the IBFCL used in distribution systems including multifeeders connected to the PCC, in addition to reducing the cost of limiting the fault current, the PCC bus voltage has effectively compensated the PCC bus. Also, comparison analysis with the conventional BFCL and TSSFCL shows that it outperforms them in terms of fault detection, voltage recovery time, and fault current limitation. [ABSTRACT FROM AUTHOR]

The V-I characteristic of ZnO varistor which has been obtained from experimental test, is an important parameter to model surge arrester electrical behavior. Generally, in grid voltage, this characteristic depends on temperature variations. In this paper, an improved metal oxide surge arrester electrical model has been proposed under grid voltage. Temperature effects on surge arrester performance have been considered in the proposed model. Artificial neural network has been used to determine V-I characteristic at temperature variations. Therefore, in proposed model, the V-I characteristic of each varistor has been estimated based on applied voltage and operating temperature. To validate proposed model, laboratory setup and infrared thermal camera have been arranged and experimental tests results have been compared with simulation ones. Results revealed that there has been a good agreement between simulation and experimental results. Moreover, electrical behavior of surge arrester is predictable with high precision through the proposed artificial model. [ABSTRACT FROM AUTHOR]

This study proposes a new method for modelling of metal‐oxide surge arresters (MOSAs) thermal balance diagram based on power loss and heat dispersion curve. Adaptive network‐based fuzzy inference system (ANFIS)‐based method was offered to compute surge arrester power loss characteristic. Thermal stability (TS) of surge arrester, which is analysed by thermal balance diagram, has a great influence on their proper functions. MOSA material variation is an important factor that has an influence on its TS. Degradation factor (DF) was introduced as a new index in this study to represent material variations of MOSA. Therefore, applied voltage, temperature and DF were considered as inputs in ANFIS model to obtain accurate power loss which is a very important factor in TS characteristic. Heat dispersion curve was obtained as a main feature in the thermal balance diagram from surge arrester cooling curve. Degrading effect was considered using voltage and current measured from MOSA which are degraded by utilisation in the network. In addition, effect of assembling process has been considered by using new different varistors in experimental measurements. This study shows that the thermal balance diagram of surge arrester is predictable with a good accuracy by using artificial model. [ABSTRACT FROM AUTHOR]

Metal–oxide surge arresters (MOSAs) are essential equipments for power system protection and devices from lightning and switching transient overvoltages. Therefore, their operating condition and diagnosis are very important. In this study, a multi‐layer support vector machine (SVM) classifier has been used for MOSA conditions monitoring based on experimental tests. Three features are extracted based on the test results for determining surge arresters operating conditions including clean virgin, ultraviolet (UV) aged clean surface, surface contaminations after and before UV housing ageing, and degraded varistors along active column. Then, the multi‐layer SVM classifier is trained with the training samples, which are extracted by the above data processing. Finally, the five fault types of surge arresters are identified by this classifier. The test results show that the classifier has an excellent performance on training speed and reliability which confirm the high applicability of introduced features for correct diagnostic of surge arresters conditions. [ABSTRACT FROM AUTHOR]

Metal-oxide surge arresters are one of the most important equipments for power system protection against switching and lightning over-voltages. Surge arresters leakage currents increase by the operating time. In this study, the important factors on leakage current variations such as surface contamination, ultraviolet ageing and varistor degradation have been studied. To accomplish this purpose, experimental tests have been performed on various polymer housed surge arresters. Fast Fourier transform analysis has been performed on measured leakage currents. Results show that ultraviolet radiation and varistor degradation affect resistive harmonic components, especially the third and fifth harmonics. Moreover, it is observed that surface contamination has influence on fundamental harmonic variation more than ultraviolet ageing. In addition, combination of ultraviolet radiation and pollution had more effect on leakage currents. The investigation and the discussion of the results can be used to easily analyse arresters condition leading to effective schedule maintenance. [ABSTRACT FROM AUTHOR]

Metal‐oxide surge arresters are one of the most important equipments for power system protection against switching and lightning over‐voltages. Surge arresters leakage currents increase by the operating time. In this study, the important factors on leakage current variations such as surface contamination, ultraviolet ageing and varistor degradation have been studied. To accomplish this purpose, experimental tests have been performed on various polymer housed surge arresters. Fast Fourier transform analysis has been performed on measured leakage currents. Results show that ultraviolet radiation and varistor degradation affect resistive harmonic components, especially the third and fifth harmonics. Moreover, it is observed that surface contamination has influence on fundamental harmonic variation more than ultraviolet ageing. In addition, combination of ultraviolet radiation and pollution had more effect on leakage currents. The investigation and the discussion of the results can be used to easily analyse arresters condition leading to effective schedule maintenance. [ABSTRACT FROM AUTHOR]