A New Method to Monitor the Primary Neutral Integrity in Multi-Grounded Neutral Systems

In the three-phase four-wire system, there are usually multiple grounding points in the primary neutral line due to safety and economic considerations. The rising “neutral to earth voltage (NEV)” caused by a broken primary neutral can threaten the safety of nearby facilities and humans; therefore, t...

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Main Authors: Xiangmin Xie, Yuanyuan Sun, Xun Long, Bingwei Zhang
Format: Article
Language:English
Published: MDPI AG 2017-03-01
Series:Energies
Subjects:
Online Access:http://www.mdpi.com/1996-1073/10/3/380
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author Xiangmin Xie
Yuanyuan Sun
Xun Long
Bingwei Zhang
author_facet Xiangmin Xie
Yuanyuan Sun
Xun Long
Bingwei Zhang
author_sort Xiangmin Xie
collection DOAJ
description In the three-phase four-wire system, there are usually multiple grounding points in the primary neutral line due to safety and economic considerations. The rising “neutral to earth voltage (NEV)” caused by a broken primary neutral can threaten the safety of nearby facilities and humans; therefore, the integrity of the primary neutral conductor is of vital importance for the multi-grounded neutral (MGN) system. In this paper, a new passive method is proposed to monitor the integrity of the primary neutral line in the MGN system. The method is based on the measured voltage and current data at the service transformer, and there is no need to install any signal generators. Therefore, it causes no disturbance to the utility and customer. In the paper, the equivalent analysis circuit is established and a new parameter is proposed to reflect the neutral condition. The value of the parameter is estimated based on the measured data, and then, the equivalent impedance of the primary neutral groundings can be obtained. On the other hand, the impedance value for the primary neutral under normal operating conditions can be estimated based on the derived analytical formulas. By comparing the monitored primary neutral impedance with its normal value, the broken neutral condition in the primary system can be detected. Different primary neutral broken cases are analyzed in the paper based on the Monte Carlo simulation. The results indicate that the integrity condition in the primary neutral can be accurately monitored by the proposed method.
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spelling doaj.art-f54f3681a8bb4458a9cdac8354b41a2f2022-12-22T04:22:47ZengMDPI AGEnergies1996-10732017-03-0110338010.3390/en10030380en10030380A New Method to Monitor the Primary Neutral Integrity in Multi-Grounded Neutral SystemsXiangmin Xie0Yuanyuan Sun1Xun Long2Bingwei Zhang3School of Electrical Engineering, Shandong University, Jinan 250061, ChinaSchool of Electrical Engineering, Shandong University, Jinan 250061, ChinaFortisAlberta, Calgary T3K6E8, AB, CanadaSchool of Electrical Engineering, Shandong University, Jinan 250061, ChinaIn the three-phase four-wire system, there are usually multiple grounding points in the primary neutral line due to safety and economic considerations. The rising “neutral to earth voltage (NEV)” caused by a broken primary neutral can threaten the safety of nearby facilities and humans; therefore, the integrity of the primary neutral conductor is of vital importance for the multi-grounded neutral (MGN) system. In this paper, a new passive method is proposed to monitor the integrity of the primary neutral line in the MGN system. The method is based on the measured voltage and current data at the service transformer, and there is no need to install any signal generators. Therefore, it causes no disturbance to the utility and customer. In the paper, the equivalent analysis circuit is established and a new parameter is proposed to reflect the neutral condition. The value of the parameter is estimated based on the measured data, and then, the equivalent impedance of the primary neutral groundings can be obtained. On the other hand, the impedance value for the primary neutral under normal operating conditions can be estimated based on the derived analytical formulas. By comparing the monitored primary neutral impedance with its normal value, the broken neutral condition in the primary system can be detected. Different primary neutral broken cases are analyzed in the paper based on the Monte Carlo simulation. The results indicate that the integrity condition in the primary neutral can be accurately monitored by the proposed method.http://www.mdpi.com/1996-1073/10/3/380primary neutral integritymulti-grounded neutral (MGN) systemneutral integrity detectionpassive method
spellingShingle Xiangmin Xie
Yuanyuan Sun
Xun Long
Bingwei Zhang
A New Method to Monitor the Primary Neutral Integrity in Multi-Grounded Neutral Systems
Energies
primary neutral integrity
multi-grounded neutral (MGN) system
neutral integrity detection
passive method
title A New Method to Monitor the Primary Neutral Integrity in Multi-Grounded Neutral Systems
title_full A New Method to Monitor the Primary Neutral Integrity in Multi-Grounded Neutral Systems
title_fullStr A New Method to Monitor the Primary Neutral Integrity in Multi-Grounded Neutral Systems
title_full_unstemmed A New Method to Monitor the Primary Neutral Integrity in Multi-Grounded Neutral Systems
title_short A New Method to Monitor the Primary Neutral Integrity in Multi-Grounded Neutral Systems
title_sort new method to monitor the primary neutral integrity in multi grounded neutral systems
topic primary neutral integrity
multi-grounded neutral (MGN) system
neutral integrity detection
passive method
url http://www.mdpi.com/1996-1073/10/3/380
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