Condition Assessment of Valve-side Bushing of Converter Transformer Based on Extension Theory

Qi, Chenchen; Xie, Jilin; Mao, Hangyin; Xie, Qing

doi:10.1109/ichve49031.2020.9279416

Cited by 3 publications

(3 citation statements)

References 6 publications

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“…The existing approaches for assessing the insulation status of valve-side bushings primarily rely on periodic offline tests. These tests involve measuring characteristic parameters such as resistance, capacitance, and dielectric loss at power frequency and comparing the results with predefined threshold values stipulated by standards to evaluate the insulation condition of the bushing 3,7 . On the basis of conventional offline inspections, Chen Ming et al from Xi'an Jiaotong University proposed the technical idea of utilizing offline frequency-domain dielectric spectrum as a characteristic parameter 6 , which significantly enhanced the sensitivity for early-stage insulation degradation detection.…”

Section: Introductionmentioning

confidence: 99%

“…It should be noted that the valve-side bushing is situated within the converter station valve hall, which deviates from the conventional locations for voltage monitoring points. Consequently, the integration of specialized voltage transformers becomes necessary, leading to challenges in terms of the feasibility of engineering implementation 3,9 .…”

Section: Introductionmentioning

confidence: 99%

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On-line insulation monitoring method for converter transformer valve side bushings based on time series correlation of leakage current

Feng,

Zhou,

et al. 2024

Ninth International Symposium on Sensors, Mechatronics, and Automation System (ISSMAS 2023)

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Valve-side bushings in converter transformers are critical components that are subjected to various transient over voltages and complex high-order harmonic voltages during normal operation. The insulation state of these bushings faces significant challenges. Existing offline inspection methods have limitations in terms of real-time performance and applicability, and they cannot fully simulate real operating conditions. Therefore, this study investigates the amplitude and phase distribution patterns of the direct voltage, power frequency, and harmonic voltages in valve-side bushings. It establishes the mapping relationship between the time series correlation of leakage current and the insulation state. Based on this, an on-line insulation monitoring method based on time series correlation of leakage current is proposed, which ensures real-time performance through data-driven approaches and applicability through mutual supervision, while maintaining the realism of operating conditions through online implementation. The results of simulation experiments demonstrate that this method could accurately identify early-stage degradation of insulation in valve-side bushings. It exhibits higher sensitivity compared to existing methods and holds significance for ensuring the safety and stability of direct current transmission systems.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On-line insulation monitoring method for converter transformer valve side bushings based on time series correlation of leakage current

Feng,

Zhou,

et al. 2024

Ninth International Symposium on Sensors, Mechatronics, and Automation System (ISSMAS 2023)

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show abstract

“…The control strategy proposed in this paper is based on ET [9] to determine the appropriate SMC gains, thereby altering the structure of the sliding mode function for faster and more stable sliding mode control response. First, the speed error between the motor's speed command and its actual speed, along with the rate of change of the speed error, are used as features for ET.…”

Section: Introductionmentioning

confidence: 99%

A Robust Controller Based on Extension Sliding Mode Theory for BLDC Motor Drives

Chao,

Hsieh,

Chen

2024

Preprint

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This paper presents the design of a robust speed controller for brushless DC motors (BLDCM) under field-oriented control (FOC). The proposed robust controller integrates extension theory (ET) and sliding mode theory (SMT) to achieve robustness. First, the speed difference between the speed command and the actual speed of the BLDCM, along with the rate of change of the speed difference, are divided into 20 interval categories. Then, the feedback speed difference and the rate of change of the speed difference are calculated for their extension correlation with each of the 20 interval categories. The interval category with the highest correlation is used to determine the appropriate control gain for the sliding mode speed controller. This gain adjustment tunes the parameters of the sliding surface in the SMT, thereby suppressing the overshoot of the motor speed. Because the sliding surface reaching law of the sliding mode controller (SMC) adopts the exponential approach law, the system's speed response can quickly follow the speed command in any state and exhibit excellent load regulation response. The simplicity of this robust control method, which requires minimal training data, facilitates easy implementation. Finally, the speed control of the BLDCM is simulated using Matlab/Simulink software, and the results are compared with those of the SMC using the constant speed approach law. The simulation results demonstrate that the proposed robust controller exhibits superior speed command tracking and load regulation response compared to the traditional SMC.

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A Robust Controller Based on Extension Sliding Mode Theory for Brushless DC Motor Drives

Chao,

Hsieh,

Chen

2024

Electronics

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This paper presents the design of a robust speed controller for brushless DC motors (BLDCMs) under field-oriented control (FOC). The proposed robust controller integrates extension theory (ET) and sliding mode theory (SMT) to achieve robustness. First, the speed difference between the speed command and the actual speed of the BLDCM, along with the rate of change of the speed difference, are divided into 20 interval categories. Then, the feedback speed difference and the rate of change of the speed difference are calculated for their extension correlation with each of the 20 interval categories. The interval category with the highest correlation is used to determine the appropriate control gain for the sliding mode speed controller. This gain adjustment tunes the parameters of the sliding surface in the SMT, thereby suppressing the overshoot of the motor’s speed. Because a sliding surface reaching law of the sliding mode controller (SMC) adopts the exponential approach law (EAL), the system’s speed response can quickly follow the speed command in any state and exhibit an excellent load regulation response. The simplicity of this robust control method, which requires minimal training data, facilitates its easy implementation. Finally, the speed control of the BLDCM is simulated using Matlab/Simulink software (2023b version), and the results are compared with those of the SMC using the constant-speed approach law (CSAL). The simulation and experimental results demonstrate that the proposed robust controller exhibits superior speed command tracking and load regulation responses compared to the traditional SMC.

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Condition Assessment of Valve-side Bushing of Converter Transformer Based on Extension Theory

Cited by 3 publications

References 6 publications

On-line insulation monitoring method for converter transformer valve side bushings based on time series correlation of leakage current

On-line insulation monitoring method for converter transformer valve side bushings based on time series correlation of leakage current

A Robust Controller Based on Extension Sliding Mode Theory for BLDC Motor Drives

A Robust Controller Based on Extension Sliding Mode Theory for Brushless DC Motor Drives

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