Insulation Online Monitoring Method for Dry-Type Current Transformers Based on Virtual Voltage

To improve the accuracy of insulation state online monitoring for capacitive dry-type current transformers (CTs) and to address the limitations of traditional methods relying on potential transformer (PT) voltage signals and reference devices, a virtual voltage-based online monitoring method is prop...

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Main Authors: Junjie Zhang, Yu Peng, Xiaohui Hu, Zhipeng Li, Li Yan, Can Ding, Ruihua Zhao
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Energies
Subjects:
Online Access:https://www.mdpi.com/1996-1073/18/13/3499
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author Junjie Zhang
Yu Peng
Xiaohui Hu
Zhipeng Li
Li Yan
Can Ding
Ruihua Zhao
author_facet Junjie Zhang
Yu Peng
Xiaohui Hu
Zhipeng Li
Li Yan
Can Ding
Ruihua Zhao
author_sort Junjie Zhang
collection DOAJ
description To improve the accuracy of insulation state online monitoring for capacitive dry-type current transformers (CTs) and to address the limitations of traditional methods relying on potential transformer (PT) voltage signals and reference devices, a virtual voltage-based online monitoring method is proposed. First, the leakage current is collected through a core-type current transformer on the end-screen grounding line. Combined with group measurement data from surge arresters and dry-type CTs on the same busbar, phase constraints are established, and a least mean square (LMS) algorithm is utilized to iteratively train the virtual voltage reference phase. Subsequently, the resistive current and dielectric loss factor (tan δ) are calculated based on the virtual voltage reference phase to achieve online insulation state monitoring. Simulation results demonstrate that the proposed method can accurately obtain the virtual voltage reference phase and effectively identify the degradation trend of dry-type CTs. Field applications validate the feasibility of the method, with monitoring data fluctuations (±20 μA for the resistive current and ±0.002 for the dielectric loss) meeting engineering requirements. This method eliminates the need for PT signals and reference devices, thus providing a novel approach for the online insulation monitoring of dry-type CTs.
format Article
id doaj-art-42b4f16ceea2415bb255e896a3f2247c
institution Kabale University
issn 1996-1073
language English
publishDate 2025-07-01
publisher MDPI AG
record_format Article
series Energies
spelling doaj-art-42b4f16ceea2415bb255e896a3f2247c2025-08-20T03:28:30ZengMDPI AGEnergies1996-10732025-07-011813349910.3390/en18133499Insulation Online Monitoring Method for Dry-Type Current Transformers Based on Virtual VoltageJunjie Zhang0Yu Peng1Xiaohui Hu2Zhipeng Li3Li Yan4Can Ding5Ruihua Zhao6Shaoguan Power Supply Bureau, Guangdong Power Grid Co., Ltd., Shaoguan 512000, ChinaShaoguan Power Supply Bureau, Guangdong Power Grid Co., Ltd., Shaoguan 512000, ChinaWuhan Kangda Electric Co., Ltd., Wuhan 430070, ChinaWuhan Kangda Electric Co., Ltd., Wuhan 430070, ChinaWuhan Kangda Electric Co., Ltd., Wuhan 430070, ChinaCollege of Electrical Engineering and New Energy, China Three Gorges University, Yichang 443000, ChinaCollege of Electrical Engineering and New Energy, China Three Gorges University, Yichang 443000, ChinaTo improve the accuracy of insulation state online monitoring for capacitive dry-type current transformers (CTs) and to address the limitations of traditional methods relying on potential transformer (PT) voltage signals and reference devices, a virtual voltage-based online monitoring method is proposed. First, the leakage current is collected through a core-type current transformer on the end-screen grounding line. Combined with group measurement data from surge arresters and dry-type CTs on the same busbar, phase constraints are established, and a least mean square (LMS) algorithm is utilized to iteratively train the virtual voltage reference phase. Subsequently, the resistive current and dielectric loss factor (tan δ) are calculated based on the virtual voltage reference phase to achieve online insulation state monitoring. Simulation results demonstrate that the proposed method can accurately obtain the virtual voltage reference phase and effectively identify the degradation trend of dry-type CTs. Field applications validate the feasibility of the method, with monitoring data fluctuations (±20 μA for the resistive current and ±0.002 for the dielectric loss) meeting engineering requirements. This method eliminates the need for PT signals and reference devices, thus providing a novel approach for the online insulation monitoring of dry-type CTs.https://www.mdpi.com/1996-1073/18/13/3499dry-type current transformerphase constraintsvirtual voltageresistive current measurementinsulation state monitoring
spellingShingle Junjie Zhang
Yu Peng
Xiaohui Hu
Zhipeng Li
Li Yan
Can Ding
Ruihua Zhao
Insulation Online Monitoring Method for Dry-Type Current Transformers Based on Virtual Voltage
Energies
dry-type current transformer
phase constraints
virtual voltage
resistive current measurement
insulation state monitoring
title Insulation Online Monitoring Method for Dry-Type Current Transformers Based on Virtual Voltage
title_full Insulation Online Monitoring Method for Dry-Type Current Transformers Based on Virtual Voltage
title_fullStr Insulation Online Monitoring Method for Dry-Type Current Transformers Based on Virtual Voltage
title_full_unstemmed Insulation Online Monitoring Method for Dry-Type Current Transformers Based on Virtual Voltage
title_short Insulation Online Monitoring Method for Dry-Type Current Transformers Based on Virtual Voltage
title_sort insulation online monitoring method for dry type current transformers based on virtual voltage
topic dry-type current transformer
phase constraints
virtual voltage
resistive current measurement
insulation state monitoring
url https://www.mdpi.com/1996-1073/18/13/3499
work_keys_str_mv AT junjiezhang insulationonlinemonitoringmethodfordrytypecurrenttransformersbasedonvirtualvoltage
AT yupeng insulationonlinemonitoringmethodfordrytypecurrenttransformersbasedonvirtualvoltage
AT xiaohuihu insulationonlinemonitoringmethodfordrytypecurrenttransformersbasedonvirtualvoltage
AT zhipengli insulationonlinemonitoringmethodfordrytypecurrenttransformersbasedonvirtualvoltage
AT liyan insulationonlinemonitoringmethodfordrytypecurrenttransformersbasedonvirtualvoltage
AT canding insulationonlinemonitoringmethodfordrytypecurrenttransformersbasedonvirtualvoltage
AT ruihuazhao insulationonlinemonitoringmethodfordrytypecurrenttransformersbasedonvirtualvoltage