A Fault Diagnosis Method for Substation Grounding Grid Based on the Square-Wave Frequency Domain Model

Zhang, Penghe; He, Junjia; Zhang, Dandan; Wu, Lanmin

doi:10.2478/v10178-012-0005-z

Cited by 27 publications

(38 citation statements)

References 8 publications

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“…The initial impedance of grounding grid is obtained according to the design specification of metal material. When the grounding grid metal suffered obvious corrosion, the cross section of metal would decrease, and consequently the impedance value of grounding grid branch would become much bigger than its initial impedance value [10]. Hence, the change of impedance could represent the corrosion degree of grounding grid directly.…”

Section: Technical Principlementioning

confidence: 99%

Corrosion Detection and Analysis of the Underground Grounding Grid in a 220kv Transformer Substation

Zhou¹,

Hu²,

Zhu³

2018

dteees

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The first corrosion detection for the large grounding grid of a 220kV substation was performed based on electrical impedance tomography (EIT) technology. The impedance value of grounding grid branch which represented the corrosion state of metal was calculated using the current and voltage data acquired on-site through injecting a direct current from one down conductor and collecting voltage data from other down conductors. The results indicated that the impedance increase ratio of the No.143 grounding grid branch in test area D was higher than the warning value (>15 times), indicating a breakage has occurred on this grounding grid branch. The two-dimension corrosion image of the whole underground grounding grid was calculated and drawn accurately and visually using the corrosion diagnosis software. The corrosion rate of carbon steel was monitored in the serious corrosion area later, to realize the online corrosion monitoring of grounding grid metal. EIT technology realized the underground grounding grid statues visible exhibition, and could be used to detect the corrosion state, corrosion area and failure location of the underground grounding grid rapidly and effectively. This could reduce the blindness of corrosion detection for grounding grid and provide guidelines on the corrosion maintenance of underground grounding grid in large substation.

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Section: Technical Principlementioning

confidence: 99%

Corrosion Detection and Analysis of the Underground Grounding Grid in a 220kv Transformer Substation

Zhou¹,

Hu²,

Zhu³

2018

dteees

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“…To some degree, the method cannot evaluate the performance of every single branch clearly. There are other kinds of solution for fault diagnosis in grounding grids, such as electrochemical method [7], the transient electromagnetic method [8,9], a frequency-domain analysis [10], the electromagnetic method [11][12][13], and the electric network method [14][15][16][17] for nondestructive testing.…”

Section: Introductionmentioning

confidence: 99%

A Cycle Voltage Measurement Method and Application in Grounding Grids Fault Location

et al. 2017

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Abstract:The corrosion of grounding grids can result in a grounding accident of a power system, and much attentions has been concentrated on the method used to detect a corrosion fault in a grounding grid, in which the methods of voltage measurement and magnetic field measurement are usually used. In this paper, a cycle voltage measurement method and L-curve regularization method are proposed to locate the faults in grounding grids. The L-curve method was used to select the appropriate regularization parameter, which can effectively balance the error and stability of the solution to the inverse problem. The uncertainty of the solution due to the ill-posed problem in the inverse problem has been well-solved. Experiments were conducted in a laboratory with two network types. In addition, a field experiment was carried out in a 110-kV substation. Both of the results showed that the method can effectively locate a branch fault with a single branch and multiple branches in the grounding grids.

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“…Mastering the conductive ability of each conductor of grounding grid can provide references for diagnosing the corrosion state of grounding grid [8]. However, Typically, the grounding grid is made out of bare copper or iron conductors, which are buried about 0.3-2 m deep under the ground, it is difficult to directly measure the current flowing through conductor of grounding grid by normal methods [9]. Ma et al [10] inject the square wave current with high frequency (~500 Hz) and high current (~10A maximum) into the grid and measure the surface magnetic induction intensity to investigate grounding grid integrity.…”

Section: Introductionmentioning

confidence: 99%

A Novel Non-contact Measurement Method for the Detection of Current Flowing Through Concealed Conductors

Yang¹,

Li²,

Zhu³

et al. 2017

Journal of Magnetics

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In order to detect the current flowing through concealed conductor, this paper proposes a new method based on derivative method. Firstly, this paper analyzes the main peak characteristic of the derivative function of magnetic field generated by a current-carrying conductor, and a relationship between the current flowing through the conductor and the main peak of the derivative function is obtained and applied to calculate the current. Then, the method is applied to detect the conductor current flowing through grounding grids of substations. Finally, the numerical experimental and field experiment verified the feasibility and accuracy of the method, and the computing results show that the method can effectively measure the conductor current of grounding grids with low error, and the error is within 5 %.

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A Fault Diagnosis Method for Substation Grounding Grid Based on the Square-Wave Frequency Domain Model

Cited by 27 publications

References 8 publications

Corrosion Detection and Analysis of the Underground Grounding Grid in a 220kv Transformer Substation

Corrosion Detection and Analysis of the Underground Grounding Grid in a 220kv Transformer Substation

A Cycle Voltage Measurement Method and Application in Grounding Grids Fault Location

A Novel Non-contact Measurement Method for the Detection of Current Flowing Through Concealed Conductors

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