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Society is increasingly dependent on continuous power supply. This is also taken into account in regulation models, where, in Finland, the customer's interruption costs CIC now directly affect the profit allowed for distribution system operators. This has led to the situation, where the CIC directly affects the network planning, including decisions on line types and line routing. Hence, more information...
This paper highlights the earth fault problem in unearthed (isolated) and compensated neutral medium voltage distribution networks and the transient-based protection as a solution. The technique of transient-based analysis will be discussed considering the sampling window, frequency and data updating. The required transient simulation analysis and its validation will be presented. Many important practical...
In a Bayesian selectivity technique has been introduced to identify the faulty feeder in compensated medium voltage (MV) networks. The proposed technique has been based on a conditional probabilistic method applied on transient features extracted from the residual currents only using the Discrete Wavelet Transform (DWT). In this paper, the performance of this selectivity technique is evaluated when...
In this paper, a Bayesian selectivity technique is introduced to identify the faulty feeder in compensated medium voltage (MV) networks. The proposed technique is based on a conditional probabilistic method applied on features extracted from the residual currents only using the discrete wavelet transform (DWT). DWT enhances to localize initial transients generated in the network due to the fault event...
In this paper, the windowed standard deviation (WSTD) is used to extract the initial transients created in residual current waveforms generated due to earth faults in medium voltage (MV) compensated networks. The sliding window width used for computing the standard deviation is evaluated from the frequency filter point of view. The fault cases occurring in a compensated 20 kV network are simulated...
Loop restoration scheme (LRS) is a special feeder automation (FA) scheme, which is used by utilities to improve distribution system reliability. The LRS is controlled and managed by its automatic control system (ACS). The impacts on distribution system reliability indices of implementing LRS mainly depend on the type of its ACS. Two common types of ACS of LRS are presented and used in this study....
This paper presents a transient fault detection technique in unearthed medium voltage systems. The system is simulated by ATP/EMTP program. A suitable fault detection window is introduced. The window width is the most sensitive part in the transient period. It is varying according to fault characteristics. The average impedance of the earth mode is calculated from voltage and current earth modes in...
A novel selectivity technique to estimate the faulty feeder in MV networks was introduced in [1]. This technique depended on the directionality of discrete wavelet transform (DWT) detail coefficient of a residual current of each feeder with respect to the DWT detail coefficient of the residual voltage. The algorithm efficacy has been examined with high impedance arcing fault due to leaning trees....
In this paper, the initial transients in the electrical network due to arc reignitions associated with high impedance faults caused by leaning trees are extracted from phase voltages and currents. The discrete wavelet transform (DWT) is used for the fault feature extraction corresponding to band frequency 12.5- 6.25 kHz and therefore localizing this fault occurrence. The detection security is enhanced...
In this paper, features of earth faults due to leaning trees are extracted from the network phase currents using the discrete wavelet transform (DWT). Due to the associated arc reignitions, the initial transients in the electrical network give behavioral traits. The detection security is also enhanced because the DWT is responded to a periodicity of the initial transients. The absolute sum of the...
Lightning storms may only last some hours, but the number of faults during these storms can represent a considerable share of the annual disturbances. In this paper, six identified lightning storms were the main interest. In general, single-phase earth faults are the most typical fault type. However, in the lightning storms we researched, short circuits represented the majority of faults. The majority...
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