Analysis and Improvement of Adaptive Coefficient Third Harmonic Voltage Differential Stator Grounding Protection

This paper presents a novel third harmonic voltage differential stator grounding protection (THV-DSGP) method combining the adaptive coefficient and fixed coefficient. It can solve the protection sensitivity degradation problem when the insulation resistance of stator winding to ground is slowly dec...

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Main Authors: Ying Zhu, Yuping Li, Jianbin Sang, Minglei Bao, Haixiang Zang
Format: Article
Language:English
Published: MDPI AG 2018-06-01
Series:Energies
Subjects:
Online Access:http://www.mdpi.com/1996-1073/11/6/1430
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spelling doaj-6ba0e689738d4d19836d5b9d870e46d92020-11-25T01:22:37ZengMDPI AGEnergies1996-10732018-06-01116143010.3390/en11061430en11061430Analysis and Improvement of Adaptive Coefficient Third Harmonic Voltage Differential Stator Grounding ProtectionYing Zhu0Yuping Li1Jianbin Sang2Minglei Bao3Haixiang Zang4College of Energy and Electrical Engineering, Hohai University, Nanjing 211100, ChinaNanjing SAC Power Grid Automation Co., Ltd., Nanjing 211100, ChinaNanjing SAC Power Grid Automation Co., Ltd., Nanjing 211100, ChinaNanjing SAC Power Grid Automation Co., Ltd., Nanjing 211100, ChinaCollege of Energy and Electrical Engineering, Hohai University, Nanjing 211100, ChinaThis paper presents a novel third harmonic voltage differential stator grounding protection (THV-DSGP) method combining the adaptive coefficient and fixed coefficient. It can solve the protection sensitivity degradation problem when the insulation resistance of stator winding to ground is slowly declining. This protection method retains the advantages of the adaptive coefficient, which is to maintain high sensitivity in case of an instantaneous ground fault. Moreover, the fixed coefficient can remember the initial insulation state of the stator winding and prevent relay failure when the stator insulation is slowly declining. In addition, due to zero-sequence voltage disconnection (ZSVD) often leading to malfunctioning of the THV stator ground protection, the existing criterion of the ZSVD was improved according to the electrical characteristics of the generator when ZSVD happens. THV-DSGP with both adaptive coefficient and fixed coefficient was simulated in the Matlab/Simulink. The simulation results show that the proposed protection can be applied to the slow ground fault of the stator winding. Furthermore, the improved criterion of ZSVD can effectively distinguish the stator metal earth fault and the secondary loop break of the zero-sequence voltage.http://www.mdpi.com/1996-1073/11/6/1430adaptive coefficientfixed coefficientthird harmonic voltagestator ground protectionsensitivitydifferentialsimulation
collection DOAJ
language English
format Article
sources DOAJ
author Ying Zhu
Yuping Li
Jianbin Sang
Minglei Bao
Haixiang Zang
spellingShingle Ying Zhu
Yuping Li
Jianbin Sang
Minglei Bao
Haixiang Zang
Analysis and Improvement of Adaptive Coefficient Third Harmonic Voltage Differential Stator Grounding Protection
Energies
adaptive coefficient
fixed coefficient
third harmonic voltage
stator ground protection
sensitivity
differential
simulation
author_facet Ying Zhu
Yuping Li
Jianbin Sang
Minglei Bao
Haixiang Zang
author_sort Ying Zhu
title Analysis and Improvement of Adaptive Coefficient Third Harmonic Voltage Differential Stator Grounding Protection
title_short Analysis and Improvement of Adaptive Coefficient Third Harmonic Voltage Differential Stator Grounding Protection
title_full Analysis and Improvement of Adaptive Coefficient Third Harmonic Voltage Differential Stator Grounding Protection
title_fullStr Analysis and Improvement of Adaptive Coefficient Third Harmonic Voltage Differential Stator Grounding Protection
title_full_unstemmed Analysis and Improvement of Adaptive Coefficient Third Harmonic Voltage Differential Stator Grounding Protection
title_sort analysis and improvement of adaptive coefficient third harmonic voltage differential stator grounding protection
publisher MDPI AG
series Energies
issn 1996-1073
publishDate 2018-06-01
description This paper presents a novel third harmonic voltage differential stator grounding protection (THV-DSGP) method combining the adaptive coefficient and fixed coefficient. It can solve the protection sensitivity degradation problem when the insulation resistance of stator winding to ground is slowly declining. This protection method retains the advantages of the adaptive coefficient, which is to maintain high sensitivity in case of an instantaneous ground fault. Moreover, the fixed coefficient can remember the initial insulation state of the stator winding and prevent relay failure when the stator insulation is slowly declining. In addition, due to zero-sequence voltage disconnection (ZSVD) often leading to malfunctioning of the THV stator ground protection, the existing criterion of the ZSVD was improved according to the electrical characteristics of the generator when ZSVD happens. THV-DSGP with both adaptive coefficient and fixed coefficient was simulated in the Matlab/Simulink. The simulation results show that the proposed protection can be applied to the slow ground fault of the stator winding. Furthermore, the improved criterion of ZSVD can effectively distinguish the stator metal earth fault and the secondary loop break of the zero-sequence voltage.
topic adaptive coefficient
fixed coefficient
third harmonic voltage
stator ground protection
sensitivity
differential
simulation
url http://www.mdpi.com/1996-1073/11/6/1430
work_keys_str_mv AT yingzhu analysisandimprovementofadaptivecoefficientthirdharmonicvoltagedifferentialstatorgroundingprotection
AT yupingli analysisandimprovementofadaptivecoefficientthirdharmonicvoltagedifferentialstatorgroundingprotection
AT jianbinsang analysisandimprovementofadaptivecoefficientthirdharmonicvoltagedifferentialstatorgroundingprotection
AT mingleibao analysisandimprovementofadaptivecoefficientthirdharmonicvoltagedifferentialstatorgroundingprotection
AT haixiangzang analysisandimprovementofadaptivecoefficientthirdharmonicvoltagedifferentialstatorgroundingprotection
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