scholarly journals Experimental investigation of insulation resistance for turbo generator digital protection

2020 ◽  
Vol 5 (2) ◽  
pp. 030-037
Author(s):  
Bernard Akindade Adaramola ◽  
Daniel Danjuma Chirpyen
Keyword(s):  
Insulation Resistance ◽  
Electrical Machinery ◽  
Experimental Procedure ◽  
Speed Test ◽  
Protection Scheme ◽  
Voltage Drops ◽  
Turbo Generator ◽  
Generator Unit ◽  
Insulation Breakdown ◽  
Digital Protection

Insulation of all electrical machinery is practically in the form of organic compounds that contain water as part of their make-up. Excessive temperature tends to dehydrate and oxidize the insulation and make it become brittle and disintegrate under vibration and shock. The insulation lifespan of turbo generators deteriorates slowly at low temperatures and more rapidly at high temperature. Economic factors, such as initial cost, replacement cost, obsolescence, and maintenance, are of prime importance when determining the years of useful service desired for the electrical insulation. Generator digital protection- fault diagnosis test was carried out to find out the cause of insulation breakdown on the turbo generator unit 411G3. The experimental procedure consists of an insulation resistance test, meggering (time-resistance absorption test), and pendulum over-speed test. A thorough investigation was conducted to identify all the stator bars that constituted the Red phase and other connections. Voltage drops on these stator bars were measured and values were used to detect ground faults which were rectified via an intelligent protection scheme.

Vibration Characteristics and Damage of Turbine Generator Shaft Rubbing

2014 ◽  
Vol 697 ◽  
pp. 210-213 ◽  
Author(s):  
Rong Pei Zhang
Keyword(s):  
Temperature Change ◽  
Vibration Characteristics ◽  
Lubricating Oil ◽  
Turbine Generator ◽  
Rotor Shaft ◽  
Turbo Generator ◽  
Deep Groove ◽  
No Elimination ◽  
Generator Unit

An abnormal journal vibration occurred when a 660MW turbo generator unit was in daily operation. It was identified that rubbing vibration had taken place based on the behavior of the journal vibration and the temperature change of lubricating oil. The rubbing was located inside the bearing box between the HIP rotor and the LP rotor. However, no elimination measures had been taken in time because the damage caused by rubbing was underestimated. Few months later a full inspection revealed that the LP rotor shaft had been worn out with a 70mm wide and 28mm deep groove, which greatly weakened the strength of the LP rotor. The analysis presented here may help in diagnosing and understanding rubbing-vibration-related problems in similar situations.

Bearing Elevation Monitoring Instrument and its Application on Multi-Support Turbo-Generator Unit

2011 ◽  
Vol 141 ◽  
pp. 218-223
Author(s):  
Yu Jie Guo ◽  
Yong Wei Tian ◽  
Jing Yu Liu ◽  
Yan Wu Bai ◽  
Wen Tao Zhang
Keyword(s):  
Elevation Change ◽  
Monitoring Instrument ◽  
Maximum Value ◽  
Turbo Generator ◽  
New Instrument ◽  
Generator Unit ◽  
Cup Design

Based on the communicating vessel principle, we present a new instrument for the measurement of bearing elevation change. A number of cups are attached to the bearings. They are linked with pipes and joints together to constitute a measurement network. Special features of the instrument to make the measurement easily and reliable, such as cup design, are presented. The instrument is used to monitor and analyze the elevation change of a 1000MW turbo-generator during the vacuum setup process. We find that the influence of vacuum on the elevation of bearing located on the exhaust cylinder is large. The maximum value is 1.8mm when vacuum changes from 0KPa to 90KPa. It causes unload of bearing #5~#8 and overload of bearing #2~#4. Adjustment project is given in the last of the paper to solve rub and pad fragment fault occurred in the unit. It is verified that the elevation adjustment for such kind of fault is valuable.

An Increment Transfer Matrix Method for the Torsional Vibration Response of Steam Turbo-Generator Shaft System

2010 ◽  
Vol 34-35 ◽  
pp. 1082-1087 ◽  
Author(s):  
Cheng Bing He ◽  
Cheng Xing ◽  
Jian Shen
Keyword(s):  
Transfer Matrix ◽  
Torsional Vibration ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Short Circuit ◽  
Nonlinear Differential Equations ◽  
Mass Model ◽  
Shaft System ◽  
Turbo Generator ◽  
Generator Unit

In order to solve nonlinear system torsion response of turbo-generator unit, an increment transfer matrix method based on step-by-step integration method and traditional transfer matrix method was put forward. The method can be directly used to analyze nonlinear differential equations. Combined with Riccati method, the increment transfer matrix method was used in a multi-mass model. And matrix equations calculating the responses of torsional vibrations were deduced. Torsional vibration resulted from the faults of short circuit and asynchronous synchronization of 600MW steam turbo-generator unit were discussed in this work by using the increment transfer matrix method which can also extend the application of transfer matrix method in nonlinear field.

Modeling and simulation of a communication-assisted digital protection scheme for micro-grids

2016 ◽  
Vol 57 ◽  
pp. 867-878 ◽  
Author(s):  
Sohrab Mirsaeidi ◽  
Dalila Mat Said ◽  
Mohd. Wazir Mustafa ◽  
Mohd. Hafiz Habibuddin ◽  
Kimia Ghaffari
Keyword(s):  
Modeling And Simulation ◽  
Protection Scheme ◽  
Digital Protection ◽  
Micro Grids

Study on the Coupled Bending and Torsional Vibrations of Turbo-Generator Unit with Rub-Impact

2012 ◽  
Vol 246-247 ◽  
pp. 1273-1277
Author(s):  
Cheng Bing He ◽  
Shi Chao Wang
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Vibration Amplitude ◽  
Critical Speed ◽  
Torsional Vibrations ◽  
Mass Model ◽  
Mass Unbalance ◽  
Turbo Generator ◽  
Generator Unit

An increment transfer matrix equations based on step-by-step integration method and traditional transfer matrix method are deduced Combined with multi-mass model and Riccati method, the increment transfer matrix method is put forward, that can be directly used to analyze the dynamic response of the coupled bending and torsional vibrations of turbo-generator shafts with rub-impact. Taking a turbo-generator unit as example, the vibration character of rub-impact fault is analyzed when unit starts up. The research results show that rubbing will make vibration amplitude increase when the rotational speed is lower than the first critical speed; however, when the speed is higher than the first critical speed, rubbing will make the rotor mass unbalance reduce, thereby vibration amplitude will reduce slightly.

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