1,662 research outputs found

    Online condition monitoring of MV cable feeders using Rogowski coil sensors for PD measurements

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    Condition monitoring is a highly effective prognostic tool for incipient insulation degradation to avoid sudden failures of electrical components and to keep the power network in operation. Improved operational performance of the sensors and effective measurement techniques could enable the development of a robust monitoring system. This paper addresses two main aspects of condition monitoring: an enhanced design of an induction sensor that has the capability of measuring partial discharge (PD) signals emerging simultaneously from medium voltage cables and transformers, and an integrated monitoring system that enables the monitoring of a wider part of the cable feeder. Having described the conventional practices along with the authors’ own experiences and research on non-intrusive solutions, this paper proposes an optimum design of a Rogowski coil that can measure the PD signals from medium voltage cables, its accessories, and the distribution transformers. The proposed PD monitoring scheme is implemented using the directional sensitivity capability of Rogowski coils and a suitable sensor installation scheme that leads to the development of an integrated monitoring model for the components of a MV cable feeder. Furthermore, the paper presents forethought regarding huge amount of PD data from various sensors using a simplified and practical approach. In the perspective of today’s changing grid, the presented idea of integrated monitoring practices provide a concept towards automated condition monitoring.fi=vertaisarvioitu|en=peerReviewed

    Online condition monitoring of MV cable feeders using Rogowski coil sensors for PD measurements

    Get PDF
    Condition monitoring is a highly effective prognostic tool for incipient insulation degradation to avoid sudden failures of electrical components and to keep the power network in operation. Improved operational performance of the sensors and effective measurement techniques could enable the development of a robust monitoring system. This paper addresses two main aspects of condition monitoring: an enhanced design of an induction sensor that has the capability of measuring partial discharge (PD) signals emerging simultaneously from medium voltage cables and transformers, and an integrated monitoring system that enables the monitoring of a wider part of the cable feeder. Having described the conventional practices along with the authors' own experiences and research on non-intrusive solutions, this paper proposes an optimum design of a Rogowski coil that can measure the PD signals from medium voltage cables, its accessories, and the distribution transformers. The proposed PD monitoring scheme is implemented using the directional sensitivity capability of Rogowski coils and a suitable sensor installation scheme that leads to the development of an integrated monitoring model for the components of a MV cable feeder. Furthermore, the paper presents forethought regarding huge amount of PD data from various sensors using a simplified and practical approach. In the perspective of today's changing grid, the presented idea of integrated monitoring practices provide a concept towards automated condition monitoring.This work is done under the project Smart Condition Monitoring of Power Grid that is funded by the Academy of Finland (Grant No. 309412)

    Propagation Characteristics of Partial discharge Signals in Medium Voltage Branched Cable Joints using HFCT Sensor

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    Rapid proliferation of underground cables in today’s distribution networks need improved fault monitoring and diagnostic capabilities. Dielectric insulation is the most critical element of underground cables and exposed to various stresses. Cable joints and terminations are always needed and are the most vulnerable locations for insulation defects within the cable feeder. Partial discharge (PD) signals emerging during the progression of insulation faults, travel along the lines and split into connected branches at the T/Y splices. This makes the use of conventional diagnostics solution inappropriate as compared to straight cable section. This paper presents a study on the propagation behaviorof PD signals in a branched joint configuration. Experimental investigations are presented to study the PD propagation across the T/Y-splices. The presented study provides interesting outcomes that can be used for development of an efficient PD monitoring system to watchdog the cable feeder.© 2019 CIREDfi=vertaisarvioitu|en=peerReviewed

    Design and Implementation of Partial Discharge Measurement Sensors for On-line Condition Assessment of Power Distribution System Components

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    Unplanned interruptions of power supply due to failure of critical components of the distribution network have considerable impact on the modern society. Efficient condition assessment can avoid the loss of critical components by early detection of incoming threats. One of the biggest shortcomings of today's progressing maintenance technology is the lack of low cost instrumentation solutions which are simple in implementation and easily applicable to the network. In this work partial discharge (PD) measurements have been considered for insulation condition assessment of distribution system components such as overhead covered conductors (CCs) and cables. A high frequency Rogowski coil induction sensor is designed for this purpose. An accurate electrical model of the sensor is necessary for efficient signal processing of the sensed signal and for reliable interpretation of the measured signal. A new method to determine the electrical parameters of Rogowski coil sensor is presented. In-depth analysis of the design stages of Rogowski coil is presented using experimental and simulated environment. Various geometrical designs of Rogowski coil are investigated to analyze the effects of geometrical parameters on high frequency performance of the coil. The guidelines presented regarding geometrical structure are useful when trading off the benefits for better mechanical and electrical design of such sensors. Location of the detected PD faults is an important task of the diagnostics system in power lines. The conventional techniques of locating PD faults have been known for a single section of a power line. However, these techniques are not suitable for power lines having multi-sections or for branched line networks. In this work, finding the location of PD fault on a power line is recognized as a two stage function; (i) identification of the faulty section, and (ii) location of fault point on the identified section. The direction of arrival (DOA) technique is introduced to identify faulty section whereas fault point location can be determined by conventional techniques. The technique is equally applicable for CC lines or cable networks. The DOA technique is integrated over a cable feeder and an on-line automated condition monitoring and diagnostic scheme is proposed. Low cost, non-intrusive installation and favorable operating features of Rogowski coil sensor make it suitable for development of an enhanced and automated diagnostic system which can easily be integrated into the distribution network

    Reliability Engineering Methods for Distribution Systems - Influence of Differences between Cable Systems and Overhead Lines

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    One way to increase distribution network reliability is to replace traditional overhead lines with underground cables. To fully utilize these investments, network owners will have to adjust their reliability engineering methods to suit the new cable networks. In this paper different condition assessment methods as well as improved failure statistics for cable systems are considered. The paper is based on information from project reports and scientific papers. In addition a number of Swedish distribution network owners have been asked to share their opinion of reliability engineering work of today and the future. The methods used for distribution system condition assessment change as overhead lines are replaced by underground cable. Visual inspections can no longer be used and diagnostic methods are instead introduced. The diagnostic methods are costly to perform. To become frequently used they must prove to be efficient enough to justify the financial means required. New, improved, diagnostic methods are under development and since most cable failures are related to component properties the use of diagnostic methods is likely to increase. Statistics show that a majority of the cable system failures are ageing failures. The ageing failures do not to any large extent depend on environmental factors but on component properties. This implies that component lifetime standard deviation decreases as component data are related to the statistics, yet failure statistics is at present not related to component data. A majority of the network owners contributing to this paper agree that the nature of cable failures, except excavation failures, makes it interesting and useful to related cable data to failure statistics and to share the statistics with other network owners. Several Swedish distribution network owners are in the process of installing new program for network analysis. One challenge is to decide which component data that shall be related to the failure statistics. Operational age, maintenance history, manufacturer and year of manufacturer are four manageable factors which influence on failure statistics is already established but yet not thoroughly evaluated. In addition the method of cable excavation is suggested as a fifth interesting factor related to cable system reliability

    Time domain analysis of switching transient fields in high voltage substations

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    Switching operations of circuit breakers and disconnect switches generate transient currents propagating along the substation busbars. At the moment of switching, the busbars temporarily acts as antennae radiating transient electromagnetic fields within the substations. The radiated fields may interfere and disrupt normal operations of electronic equipment used within the substation for measurement, control and communication purposes. Hence there is the need to fully characterise the substation electromagnetic environment as early as the design stage of substation planning and operation to ensure safe operations of the electronic equipment. This paper deals with the computation of transient electromagnetic fields due to switching within a high voltage air-insulated substation (AIS) using the finite difference time domain (FDTD) metho

    Selected Papers from 2020 IEEE International Conference on High Voltage Engineering (ICHVE 2020)

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    The 2020 IEEE International Conference on High Voltage Engineering (ICHVE 2020) was held on 6–10 September 2020 in Beijing, China. The conference was organized by the Tsinghua University, China, and endorsed by the IEEE Dielectrics and Electrical Insulation Society. This conference has attracted a great deal of attention from researchers around the world in the field of high voltage engineering. The forum offered the opportunity to present the latest developments and different emerging challenges in high voltage engineering, including the topics of ultra-high voltage, smart grids, and insulating materials
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