Impact of Negative Sequence Current on Electromagnetic Torque in Nuclear Power and Large Size Turbo‐Generators

2021 ◽  
Author(s):  
Pin Lv ◽  
Xiaojie Wu ◽  
Xunwen Su ◽  
Xianhui Zhu ◽  
Ying Yang ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Electromagnetic Torque ◽  
Negative Sequence ◽  
Large Size ◽  
Negative Sequence Current

Analysis of Negative Sequence Operation Characteristics for Nuclear Half Speed Steam Turbine Generator

2014 ◽  
Vol 1070-1072 ◽  
pp. 361-366
Author(s):  
Chuan You Dong ◽  
Bao Jun Ge ◽  
Yan Ling Lv ◽  
Da Jun Tao
Keyword(s):  
Service Life ◽  
Nuclear Power ◽  
Key Factors ◽  
Negative Sequence ◽  
Turbo Generator ◽  
Operation Process ◽  
Analysis Theory ◽  
Thermal Generator ◽  
Transient Thermal ◽  
Negative Sequence Current

The development of China's nuclear power industry is very rapid in recent years, nuclear generator also gets great development. With the increase of generator unit capacity, The service life and reliability of the generator is improved too. Among them, transient thermal generator operation ability is one of the key factors that affects the service life and reliability of generator. This paper mainly carries on to the generator produces in asymmetric operation process of negative sequence current and transient negative sequence component analysis theory, and with a turbo generator as an example, the voltage and current in different running states of the generator and the air gap flux density were compared and analyzed with finite element method. The conclusion of this paper has reference significance to deeply research the future of generator negative sequence component.

scholarly journals Turn-to-Turn Fault Diagnosis on Three-Phase Power Transformer Using Hybrid Detection Algorithm

2021 ◽  
Vol 11 (6) ◽  
pp. 2608
Author(s):  
Chien-Hsun Liu ◽  
Willybrordus H. P. Muda ◽  
Cheng-Chien Kuo
Keyword(s):  
Fuzzy System ◽  
Power Transformer ◽  
Detection Algorithm ◽  
Current Response ◽  
Negative Sequence ◽  
Three Phase ◽  
Hybrid Detection ◽  
Incipient Faults ◽  
Increase In Accuracy ◽  
Negative Sequence Current

A power transformer (PT) in power generation or transmission is critical to maintaining electrical continuity. Fault detection on a PT is needed, especially of incipient faults, which are often caused by a turn-to-turn fault (TTF) before it develops into a more severe fault. We use a hybrid algorithm between conventional and modern techniques to detect a developing fault in a PT. The current response signals from a negative sequence current directional algorithm, extended park vector algorithm (EPVA), differential negative sequence current, and EPVA-fuzzy system are combined to distinguish the possibility of a TTF. The subalgorithms are combined using a hybrid detection algorithm to distinguish the faults. The model is a 10 MVA, three-phase PT with Δ-Y configuration 150/300 kV, simulated using MATLAB Simulink software. The results show that by combining the subalgorithms, several limitations are distinguished within the TTF with a slight increase in accuracy.

scholarly journals A New Protection Strategy Based on Negative Sequence Current Coordinated Control on the Generator Extremity

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 135329-135338
Author(s):  
Zhenxing Li ◽  
Zhihao Xie ◽  
Zhenyu Wang ◽  
Hanli Weng ◽  
Lu Wang
Keyword(s):  
Coordinated Control ◽  
Negative Sequence ◽  
Protection Strategy ◽  
Negative Sequence Current

scholarly journals Non-Directional Earth Fault Passage Indication in Isolated Neutral Distribution Networks

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4732
Author(s):  
Amir Farughian ◽  
Lauri Kumpulainen ◽  
Kimmo Kauhaniemi
Keyword(s):  
Single Phase ◽  
Distribution Networks ◽  
Voltage Measurement ◽  
Negative Sequence ◽  
Overhead Lines ◽  
New Methods ◽  
Zero Sequence ◽  
Isolated Neutral ◽  
Negative Sequence Current ◽  
Symmetrical Sequence

In this paper, two new methods for locating single-phase to ground faults in isolated neutral distribution networks are proposed. The methods are based on the analysis of symmetrical sequence currents. They are solely based on currents, not requiring voltage measurement. The first method employs only the zero sequence current and the second one utilizes the negative sequence current in combination with the zero sequence current. It is revealed why using only zero sequence current with a simple threshold is insufficient and may lead to false results. Using the proposed methods, earth faults with high resistances can be located in isolated neutral distribution networks with overhead lines or cables.

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