Apparent impedance seen at generator terminal for faults on HV side of Delta-Star generator transformer

2011 ◽  
Author(s):  
A. V. S. S. R. Sai ◽  
Sachin Srivastava ◽  
Sethuraman Ganesan ◽  
Suresh Maturu
Keyword(s):  
Generator Terminal

Applications of ANFIS in Loss of Excitation Faults Detection in Hydro-Generators

2016 ◽  
Vol 5 (2) ◽  
pp. 63-79 ◽  
Author(s):  
Mohamed Salah El-Din Ahmed Abdel Aziz ◽  
Mohamed El Samahy ◽  
Mohamed A. Moustafa Hassan ◽  
Fahmy El Bendary
Keyword(s):  
Design Process ◽  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Inference System ◽  
Impedance Measurements ◽  
Line Voltage ◽  
Artificial Intelligent ◽  
Phase Current ◽  
Neuro Fuzzy ◽  
Generator Terminal

This article presents a new methodology for Loss of Excitation (LOE) faults detection in Hydro-generators using Adaptive Neuro Fuzzy Inference System. The proposed structure was trained by data from simulation of a 345kV system under different faults conditions and tested for various loading conditions. Details of the design process and the results of performance using the proposed technique are discussed in the article. Two different techniques are discussed in this article according to the type of inputs to the proposed ANFIS unit, the generator terminal impedance measurements (R and X) and the generator RMS Line to Line voltage and Phase current (Vtrms and Ia). The two proposed techniques results are compared with each other and are compared with the traditional distance relay response in addition to other techniques. The results show that the proposed Artificial Intelligent based technique is efficient in the Loss of Excitation faults (LOE) detection process. The obtained results are very promising.

The Comparative Analysis of SVC and STATCOM on Subsynchronous Oscillation Mitigation

2013 ◽  
Vol 756-759 ◽  
pp. 245-249 ◽  
Author(s):  
Jian Zhang ◽  
Xiang Ning Xiao ◽  
Ben Feng Gao ◽  
Chao Luo
Keyword(s):  
Short Circuit ◽  
Time Domain Simulation ◽  
Subsynchronous Oscillation ◽  
Damping Coefficients ◽  
Torque Coefficient ◽  
Electrical Damping ◽  
The Time Domain ◽  
Generator Terminal ◽  
Short Circuit Fault ◽  
Signal Method

The methods for subsynchronous oscillation mitigation based on SVC and STATCOM are analyzed in this paper. According to the IEEE first benchmark model, the electrical damping coefficients respectively provided by SVC and STATCOM connected at the generator terminal, as well as positive damping condition, are deduced by complex torque coefficient approach. Correlative factors which influence the two positive dampings are compared. The analysis results indicate that the positive damping provided by SVC is proportional to the size of system voltage. The positive damping provided by STATCOM is not affected by the size of system voltage, which is mostly proportional to the subsynchronous voltage produced itself. The controllers of SVC and STATCOM are designed and the positive dampings separately offered by SVC and STATCOM are optimized by phase compensation with test signal method. The time domain simulation reveals that STATCOM has stronger damping ability than SVC in the case of short circuit fault.

Effects of Electric Machine Parameters on Dynamics of an Isolated Wind-Diesel System

2013 ◽  
Vol 339 ◽  
pp. 586-590
Author(s):  
Chi Hsiang Lin
Keyword(s):  
Electric Machine ◽  
Induction Generator ◽  
Electromagnetic Torque ◽  
Electrical Parameters ◽  
Rotor Resistance ◽  
High Penetration ◽  
Terminal Voltage ◽  
Generator Terminal ◽  
System Frequency

In this paper, dynamics of a high-penetration, no-storage wind-diesel (HPNSWD) system subjected to line faults are studied. It is found that the effect of induction generator electrical parameters on generator electromagnetic torque, system frequency and generator terminal voltage is significant, especially the rotor resistance.

scholarly journals Shafting Torsional Vibration Analysis of 1000 MW Unit under Electrical Short-Circuit Fault

2021 ◽  
Vol 11 (19) ◽  
pp. 9205
Author(s):  
Honggang Pan ◽  
Yunshi Wu ◽  
Zhiyuan Pang ◽  
Yanming Fu ◽  
Tianyu Zhao
Keyword(s):  
Short Circuit ◽  
Power Grid ◽  
Two Phase ◽  
Shaft System ◽  
Three Phase ◽  
Speed Fluctuation ◽  
Grid Side ◽  
Generator Terminal ◽  
The Impact ◽  
Short Circuit Fault

Taking a 1000 MW turbine generator as the research object, the short-circuit fault in electrical disturbance is analyzed. Since it is very difficult to carry out fault analysis experiments and research on actual systems, simulation analysis is one of the more effective means of electrical fault diagnosis; the simulation’s results approach the actual behavior of the system and are ideal tools for power system analysis, and can provide an empirical basis for practical applications. The short-circuit fault model of the SIMULINK power system is built to analyze the two types of faults of generator terminals short-circuit and power grid short-circuit. The impact load spectrum, fault current and speed fluctuation between low-voltage rotors were extracted and analyzed. The conclusion is that the impact value of electromagnetic torque at the generator terminal is greater than that on the power grid side. The impact value of a two-phase short-circuit at the generator terminal is the largest, and that of a three-phase short-circuit on the power grid side is the smallest. The transient impulse current of a three-phase short-circuit at any fault point is greater than that of a two-phase short-circuit; the impulse current of the grid side short-circuit is much greater than that of the generator terminal short-circuit; the speed fluctuation and fluctuation difference caused by the three-phase short-circuit in the grid side are the largest. The alternating frequency of the transient electromagnetic force of the four kinds of faults avoids the natural frequency of the torsional vibration of the shaft system, and the torsional resonance of the shaft system in the time domain of the short-circuit fault will not appear. However, after the fault is removed, the residual small fluctuation torque in the system has a potential impact on the rotor system. This research shows an analysis of the structural integrity and safe operation of turbine generator units after a short-circuit fault, which can not only be applied to engineering practice, but also provide a theoretical basis for subsequent research.

Loss of Excitation Protection of Medium Voltage Hydro Generators Using Adaptive Neuro Fuzzy Inference System

2018 ◽  
pp. 253-285
Author(s):  
Mohamed Salah El-Din Ahmed Abdel Aziz ◽  
Mohamed Ahmed Moustafa Hassan ◽  
Fahmy M. A. Bendary
Keyword(s):  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Positive Sequence ◽  
Inference System ◽  
Phase Current ◽  
Neuro Fuzzy ◽  
Sequence Components ◽  
Terminal Voltage ◽  
Generator Terminal ◽  
Excitation Conditions

This chapter presents a new method for loss of excitation (LOE) faults detection in hydro-generators using adaptive neuro fuzzy inference system (ANFIS). The investigations were done under a complete loss of excitation conditions, and a partial loss of excitation conditions in different generator loading conditions. In this chapter, four different techniques are discussed according to the type of inputs to the proposed ANFIS unit, the generator terminal impedance measurements (R and X) and the generator terminal voltage and phase current (Vtrms and Ia), the positive sequence components of the generator terminal voltage magnitude, phase current magnitude and angle (│V+ve│, │I+ve│ and ∟I+ve) in addition to the stator current 3rd harmonics components (magnitudes and angles). The proposed techniques' results are compared with each other and are compared with the conventional distance relay response in addition to other techniques. The promising obtained results show that the proposed technique is efficient.

Open-Delta VSC Based Voltage Controller in Isolated Power Systems

2015 ◽  
Vol 6 (2) ◽  
pp. 376
Author(s):  
Shilpi Bhattacharya ◽  
Prabal Deb ◽  
Sujit K Biswas ◽  
Ambarnath Banerjee
Keyword(s):  
Power Systems ◽  
Power System ◽  
Induction Generator ◽  
Insulated Gate Bipolar Transistor ◽  
Voltage Drops ◽  
Voltage Controller ◽  
Asynchronous Generator ◽  
Generator Terminal ◽  
And Control ◽  
Generating System

<p>This paper proposes a reduced switch Open-Delta (OD-VSC) voltage controller for an standalone asynchronous generator (SAG), also known as the self-excited induction generator (SEIG),used in constant power applications such as pico hydro uncontrolled turbine driven isolated induction generator (IAG) for feeding three-phase loads. The proposed reduced switch voltage controller is used to regulate and control the generator terminal voltage as it is subjected to voltage drops, dips or flickers when the isolated power system is subjected to various critical loads. Generally this purpose is carried out by a STATCOM comprising of a three-leg six-switch inverter structure. Here, in this work the DSTATCOM is realized using a three-leg four-switch insulated gate bipolar transistor (IGBT)-based current controlled voltage-sourced converter (CC-VSC) and a self-supporting dc bus containing two split capacitors. The proposed generating system along with the controller is modeled and simulated in MATLAB along with Simulink and power system blockset (PSB) toolboxes. The system is simulated and the capability of the isolated generating system along with the reduced switch based voltage controller is presented here where the generator feeds linear and non-linear loads are investigated.</p>

Development and Field Experiments of a Generator Terminal Subsynchronous Damper

2014 ◽  
Vol 29 (4) ◽  
pp. 1693-1701 ◽  
Author(s):  
Xiaorong Xie ◽  
Liang Wang ◽  
Xijiu Guo ◽  
Qirong Jiang ◽  
Quan Liu ◽  
...  
Keyword(s):  
Field Experiments ◽  
Generator Terminal
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