Method for online measurement of optical current transformer onsite errors

Zhao, Shuangshuang; Yang, Shihai; Lu, Shufeng; Chen, Mingming; Xu, Minrui

doi:10.1088/0957-0233/27/2/025014

Cited by 3 publications

(5 citation statements)

References 16 publications

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“…It is necessary to properly increase I m 1 to eliminate the current negative error mentioned above or to minimize the current error to zero. According to (2), it is the product of I 2 and k C that is required to be increased. This can be achieved by increasing I 2 or k C .…”

Section: Turns Ratio In Appropriate Less Than Current Ratio Achieves ...mentioning

confidence: 99%

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Difficulties in producing CT caused by the current ratio regulation in IEC standard and suggestions of modification

Gan,

You,

Duan

et al. 2024

Meas. Sci. Technol.

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The integer current ratio requirements by standard IEC 61869-2 and users result in the numbers of current transformer (CT) winding turns being decimal, such as 5.94, 9.9, and 14.85. This makes the manufacturing of CTs complex, causing socioeconomic waste. It is pointed out in this paper that if the integer current ratio requirements can be changed to decimals, the number of CT winding turns may be made an integer, which makes it easy to produce low-error CTs. The error refers to the difference between the actual current ratio and the required current ratio for CTs. Additionally, if this change is made, iron core materials do not need to have high permeability. Furthermore, it is better to allow the manufacturers to mark freely the current ratio within a certain range on CT rating plates. The measure of changing the current ratio requirements or changing the way of marking the ratio on rating plates can significantly reduce the manufacturing difficulties and costs of CTs.

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Section: Turns Ratio In Appropriate Less Than Current Ratio Achieves ...mentioning

confidence: 99%

“…Measuring current transformer (CT) is a device that transforms the current. The purpose of the transformation is to determine the current value suitable for measurement on the secondary side of the CTs [1,2]. Moreover, there are generally two main purposes for measuring currents.…”

Section: Introductionmentioning

confidence: 99%

Difficulties in producing CT caused by the current ratio regulation in IEC standard and suggestions of modification

Gan,

You,

Duan

et al. 2024

Meas. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…However, the major drawback of Langevin function is its inability to accurately match the slope of the B-H loop in the shoulder region, necessitating the need to replace it. The novel function with additional parameters (19) provides improved flexibility to trace a B-H loop with a better overall shape. Additionally, a dynamic regional saturation model for protective CTs based on dynamic J-A theory was proposed in [27].…”

Section: Test System To Implement Ekf Algorithmmentioning

confidence: 99%

“…Alternatively, Optical CTs (OCTs) [19] can be employed in the place of magnetic/conventional CTs. As studied experimentally in [20], an OCT is not saturated by the dc offset current under simulated short circuit conditions and also gives acceptable performance with white noise.…”

Section: Introductionmentioning

confidence: 99%

Improving distance relay performance for heavily distorted voltage and current by accurate signal reconstruction using extended Kalman filter

NAIR¹,

DEVIKA²,

Raj³

et al. 2023

Meas. Sci. Technol.

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Distance relay plays a pivotal role in the detection of faults and subsequent isolation in transmission lines. However, severe distortion in the measured voltage and current waveforms (such as due to Current Transformer (CT) saturation), affects their performance. This paper focuses on a compensation method for signal reconstruction using Extended Kalman Filter (EKF) algorithm to improve relay functioning, enhancing the safety of transmission lines. The proposed fault detection scheme was tested extensively by running simulations using PSCAD and MATLAB for different types of faults at various distances and CT burden. The CT model in PSCAD was developed based on the Jiles-Atherton phenomenological theory in order to closely resemble a real-time CT with its saturation effects. The simulation results show that the proposed method is highly efficient in determining the exact fault point with improved zone approaching times even with measured signals having high noise and harmonic content. In cases where the conventional relay fails to detect the fault in the correct zone, the compensated data from the proposed method accurately detects the zone. Hardware experimental tests were carried out to further verify the effectiveness of the scheme in real-time, where the EKF based algorithm was implemented using a DSP-based microcontroller

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“…As one of the main sensing devices of the smart grid, electronic current transformers are widely used in smart substations because of their simple insulation structure, digital interface, wide measurement band, large dynamic range,and other advantages [1][2][3][4][5], which support the development of the digital construction of the smart grid in Li et al [6].…”

Section: Introductionmentioning

confidence: 99%

Error Model and Forecasting Method for Electronic Current Transformers Based on LSTM

2023

Teh. vjesn.

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As an important metering apparatus at the trade settlement gate in intelligent substations, the operating error of electronic current transformers can have an important impact on the electric energy trade settlement, so it is necessary to predict the error state of electronic current transformers. In this paper, a Long Short-Term Memory (LSTM) neural network is used to construct an error prediction model for electronic current transformers, characterizing their errors in the form of multiple input variables and single output variables. In order to reduce the training scale of the LSTM neural network, the partitioning around medoid (PAM) clustering algorithm is used to cluster and analyze the input variables. The analysis results of the algorithm show that the prediction results of the ratio and phase errors meet the requirements of online monitoring and provide information on the change of the error state of electronic current transformers to prevent the risk of electricity trade settlement.

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Method for online measurement of optical current transformer onsite errors

Cited by 3 publications

References 16 publications

Difficulties in producing CT caused by the current ratio regulation in IEC standard and suggestions of modification

Difficulties in producing CT caused by the current ratio regulation in IEC standard and suggestions of modification

Improving distance relay performance for heavily distorted voltage and current by accurate signal reconstruction using extended Kalman filter

Error Model and Forecasting Method for Electronic Current Transformers Based on LSTM

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