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This paper presents a novel voltage-based protection element using MODWT wavelet coefficients. This helps improve the sensitivity of existing current-based protection which can be subjected to sensitivity issues given the evolving distribution grids with multiple generation sites. The analysis of the voltage transient immediately after a disturbance can provide much useful information about the nature...
Capacitor banks are commonly connected to the power system to enhance its reliability by providing voltage support, improving power factor, and increasing the system capacity. They are usually switched in and out of the system according to the amount of connected load. This paper analyzes the measurement data of a distribution utility with shunt capacitor banks located downstream from the power quality...
Voltage sags and switching transients are the most common power quality disturbances which affect many customers in the distribution system. Detection methods are required to quantify these aspects of the quality of the power supply. Voltage sags and switching transient which occur at higher voltages will normally spread through a utility system and will be transmitted to lower voltage systems. In...
High Impedance Fault (HIF) has long been a challenging problem in network protection. This is because of its difficulty to be detected and discriminated accurately and reliably. In real cases, arcing is usually associated with HIFs. In this paper, arcing currents are produced by setting up a HV experiment. Normal switching transients are also produced by simulation or experiment. They are then analysed...
Although capacitors provide voltage support and correct displacement power factor on power distribution lines, capacitor switching transients are the second most common power quality events, after voltage sags. Capacitor switching transients can disrupt loads that are sensitive to overvoltage sub-cycle transients, including adjustable speed drives, data communication systems and process controls....
This paper presents an effective technique for tracking and finding the direction of switched capacitor banks in distribution system that generate switching transient when certain number of power quality meters exist. This technique uses modal current and voltage signals that can be constructed by combining three-phase current and three-phase voltage. This method consists of two indices. First index...
According to the International Technology Roadmap for Semiconductors (ITRS) future VLSI devices of gigahertz capability are expected to have feature sizes below 45 nm with DC power supply requirements with sub 1V and the equivalent noise voltages close to the DC rail values. This scenario makes the surge resist capability of processor type loads and the associated power conversion interfaces with...
Connecting distributed generators to the normal radial distribution system improve the power quality and increase the capacity of the electric grid. However, they disturb the radial nature of the network and thus give rise to many problems. Unintentional islanding is one of the encountered problems. In this paper a neuro-wavelet islanding detection technique has been developed. The method is based...
This paper presents a wavelet based technique for detection and classification of abnormal conditions that occur on power distribution lines. The transients associated with these conditions contain a large spectrum of frequencies, which are analyzed using wavelet transform approach. The proposed technique depends on a sensitive fault detection parameter (denoted SFD) calculated from wavelet multi-resolution...
In this paper, a method is proposed for determining the exact location of switched capacitor banks in distribution systems. The method consists of two steps. In the first step, the technique is based on measurement of voltage and current transients created by capacitor switching. The hypothesis states that: The slope of voltage and current transient wave forms created by capacitor switching immediately...
Capacitor bank switching classification using scale selection continuous wavelet transform is an approach to develop power quality diagnostic feature to analyze the origin and possible cause of transient disturbance in the industry facility. The scale selection wavelet transform selectively perform continuous wavelet transform from scale 1 to scale 70 at the dilation interval of one per scale whereby...
In this paper, a new method is proposed for tracking and finding the location of shunt switched capacitor banks in distribution systems. The technique is based on measurement of voltage and current transients created by capacitor switching. The hypothesis states that: ??the slope of voltage and current transient waveforms created by capacitor switching immediately before and after the switching instant...
In this paper a novel algorithm is proposed in order to determine the exact location of switched capacitor banks in distribution systems. The method consists of two steps. In the first step, the direction of switched capacitor bank is determined by evaluating power factor changes before and after the switching instant. In the second step, a method based on linear circuit theory is used to estimate...
Deregulation and embedded generation are two important reasons for the recent interest in power quality. Other important reasons are the increased emission of disturbances by equipment and the increased susceptibility of equipment, production processes, and manufacturing industry to voltage disturbances. Thus it is essential to establish a real time power quality monitoring system to detect power...
The transient caused by capacitor switching is an important power quality (PQ) problem. Switching the capacitor may cause a disturbance to a voltage-sensitive load or a resonance in the system. This paper presents a new method to identify the positions of the transients caused by capacitors through the PQ monitoring system. The discrete wavelet transform is used to extract the features of transients...
This paper investigates the applicability of decision tree based classifiers and hidden Markov model based classifiers to distinguish the transients originating from the faults from the transients due to normal switching events. Current signals due to different types of events such as faults, load switching, and capacitor bank switching were generated using a high voltage transmission system simulated...
This paper presents a discrete wavelet transform approach to recognize disturbances by the analysis of electromagnetic transients in transmission lines using oscillographic data. It is usual that different types of disturbances simultaneously exist in an oscillographic record supplied by a monitoring device in a transmission line. However, most of the existing methods treat the events as a single...
High-resistance grounding is implemented in the DC zonal electric distribution system (DCZEDS) to permit continuity of service during a ground fault. To prevent subsequent phase-to-ground faults on the other phase from causing a disruptive phase-to-phase fault, it is of great importance that fast and robust ground fault location methods be applied to the DCZEDS. Current fault locating techniques have...
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