Vibration Investigation for Low Pressure Turbine Last Stage Blade Failure in Steam Turbines of a Power Plant

2012 ◽  
Author(s):  
Jyoti K. Sinha ◽  
W. Hahn ◽  
K. Elbhbah ◽  
G. Tasker ◽  
I. Ullah
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Steam Turbines ◽  
Cause Analysis ◽  
Low Pressure Turbine ◽  
Root Cause ◽  
Turbo Generator ◽  
Last Stage ◽  
Blade Failure

West Burton Power Plant, UK owned by EDF energy has 4 steam turbo-generator (TG) units for power generation. These units were installed and commissioned between 1967 and 1969 and have since operated smoothly without any major problems up to 2007. In 1995 and 1996, two TG sets, namely units 2 and 3, were retrofitted with the new design LP rotors and in 2005, retrofitting of HP rotor for all four TG units was commenced. The retrofitting was done without changing the foundation, but only with the aim to enhance the power output by 20MW (10 MW through LP retrofit and 10MW through HP retrofit). Cracking of the last stage blades of LP1 and LP2 turbine, steam-end blades has been observed in TG units 2 and 3 only. Hence the in-situ vibration measurements have been carried out on TG unit 3 and compared with healthy TG unit 1 to understand the dynamics of both units. This paper presents observations made on the dynamics of TG units 1 and 3, and results from the root cause analysis which may possibly lead to the solution to the blade failure problem in TG units 2 and 3.

Root Cause Analysis of the Power Generation Capability Decrease After the 5th Refuelling Outage of Ling Ao 2

2010 ◽  
Author(s):  
Zhiyuan Chi ◽  
Weidong Chai ◽  
Dayong Zhang ◽  
Kang Dong ◽  
Guoyun Wang ◽  
...  
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Root Cause Analysis ◽  
Cause Analysis ◽  
Root Cause ◽  
Before And After

The power generation capability of Unit 2 of Ling Ao Nuclear Power Plant has been decreased about 6MW after its fifth refueling outage in 2008. This paper investigates the activities which may influence the unit capability in the outage, compares the related parameters before and after the outage, and then analyzes its root causes. From the root cause analysis, it can be found that the replacement of orifices which measure the feedwater flow was the main reason for the capability decrease. Finally, some modification measurements have been provided to recover the unit capability.

Sequential vs Multidisciplinary Coupled Optimization and Efficient Surrogate Modelling of a Last Stage and the Successive Axial Radial Diffuser in a Low Pressure Steam Turbine

2014 ◽  
Author(s):  
Kevin Cremanns ◽  
Dirk Roos ◽  
Arne Graßmann
Keyword(s):  
Steam Turbine ◽  
Design Process ◽  
Energy Demand ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Low Pressure ◽  
Steam Turbines ◽  
Low Pressure Turbine ◽  
Pressure Steam ◽  
Last Stage

In order to meet the requirements of rising energy demand, one goal in the design process of modern steam turbines is to achieve high efficiencies. A major gain in efficiency is expected from the optimization of the last stage and the subsequent diffuser of a low pressure turbine (LP). The aim of such optimization is to minimize the losses due to separations or inefficient blade or diffuser design. In the usual design process, as is state of the art in the industry, the last stage of the LP and the diffuser is designed and optimized sequentially. The potential physical coupling effects are not considered. Therefore the aim of this paper is to perform both a sequential and coupled optimization of a low pressure steam turbine followed by an axial radial diffuser and subsequently to compare results. In addition to the flow simulation, mechanical and modal analysis is also carried out in order to satisfy the constraints regarding the natural frequencies and stresses. This permits the use of a meta-model, which allows very time efficient three dimensional (3D) calculations to account for all flow field effects.

Application of GE Low Load Package on an Existing District Heating Power Plant: A Case Study

2020 ◽  
Author(s):  
Antonio Mambro ◽  
Francesco Congiu ◽  
Francesco Piraccini
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
District Heating ◽  
Low Pressure ◽  
Heating Power ◽  
Low Pressure Turbine ◽  
Low Load ◽  
Flow Through ◽  
Last Stage

Abstract The continuous increase of variable renewable energy and fuel cost requires steam turbine power plants to operate with high flexibility. Furthermore, the reduction in electricity price is forcing many existing and new district heating power plants to further optimize the heat production to maintain a sustainable business. This situation leads to low pressure steam turbines running at very low volume flow for an extended time. In this work, a case study of an existing 30 MWel district heating power plant located in Europe is presented. The customer request was the removal of the steam turbine last two stages along with the condenser to maximize steam delivery for district heating operations. However, based on the experience gained by GE on low load during the last years, the same heat production has been guaranteed without any significant impact on the existing unit, excluding any major modification of the plant layout such as last stage blading and condenser removal. Making use of the latest low flow modeling, the minimum cooling flow through the low-pressure turbine has been reduced by more than 90% compared to the existing unit. Optimization of the hood spray system and logic will reduce trailing edge erosion during low load operation leading to a significant extension in the last stage blade lifetime. These modifications, commercialized by GE as the Advanced Low Load Package (ALLP), provide a cheap, flexible and effective solution for the customer. With today’s knowledge, GE has the capability to guarantee low load operation minimizing the mass flow through the low-pressure turbine to the minimum required for safe operation. As a benefit to the customer, this option allows a gain in operational income of about 1.5 M€ per year.

Tri-Directional TEM Failure Analysis on Sample Prepared by In-Situ Lift-Out FIB and Flipstage

2014 ◽  
Author(s):  
Jie Zhu ◽  
An Yan Du ◽  
Bing Hai Liu ◽  
Eddie Er ◽  
Si Ping Zhao ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Failure Analysis ◽  
Cross Section ◽  
Root Cause Analysis ◽  
Wafer Surface ◽  
Tem Analysis ◽  
Cause Analysis ◽  
Root Cause

Abstract In this paper, we report an advanced sample preparation methodology using in-situ lift-out FIB and Flipstage for tridirectional TEM failure analysis. A planar-view and two cross-section TEM samples were prepared from the same target. Firstly, a planar-view lamellar parallel to the wafer surface was prepared using in-situ lift-out FIB milling. Upon TEM analysis, the planar sample was further milled in the along-gate and cross-gate directions separately. Eventually, a pillar-like sample containing a single transistor gate was obtained. Using this technique, we are able to analyze the defect from three perpendicular directions and obtain more information on the defect for failure root-cause analysis. A MOSFETs case study is described to demonstrate the procedure and advantages of this technique.

Root Cause Analysis of Steam Turbine Blade Failure

2015 ◽  
Vol 69 (2) ◽  
pp. 659-663 ◽  
Author(s):  
M. C. Antony Harison ◽  
M. Swamy ◽  
A. H. V. Pavan ◽  
G. Jayaraman
Keyword(s):  
Steam Turbine ◽  
Turbine Blade ◽  
Root Cause Analysis ◽  
Cause Analysis ◽  
Root Cause ◽  
Steam Turbine Blade ◽  
Blade Failure ◽  
Turbine Blade Failure

Modeling and Control of Excitation Systems for Synchronous Generators

2011 ◽  
Vol 148-149 ◽  
pp. 983-986
Author(s):  
Farouk Naeim ◽  
Sheng Liu ◽  
Lan Yong Zhang
Keyword(s):  
Power Generation ◽  
Power Plant ◽  
Electrical Power ◽  
Control Element ◽  
Steam Turbines ◽  
Synchronous Generators ◽  
Power Station ◽  
Modeling And Control ◽  
Generation Cost ◽  
And Control

The electrical power generation and distribution in power plant suffers from so many problems, such as instability of demand and generation. These lead to increase of generation cost. The system under consideration is consist of two steam turbines each of 30 MW with total of 60 MW (2*30). The excitation system of 30 MW generators has been chosen, due to the problems faced by operators in power station. These problems include aging of the control element, feeding back signal and loading increase/ decrease problems.

Advanced Last Stage Blade for Nuclear Power Plant Upgrades

2019 ◽  
Author(s):  
Christian Siewert ◽  
James R. McCracken ◽  
Thomas Thiemann
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Electrical Power ◽  
Measurement Data ◽  
Vibration Measurement ◽  
Operational Experience ◽  
Steam Turbines ◽  
Ambient Conditions ◽  
Operational Conditions ◽  
Last Stage

Abstract Utility steam turbines for electrical power generation are used at many places worldwide with different ambient conditions and different power plant configurations resulting in a variety of environmental and operational conditions. In some environments and operational conditions excitation mechanisms exist which may result in elevated Last Stage Blade vibrations. A particular example occurs in some steam turbine modernization projects, in which modern Last Stage Blade designs are applied in configurations with retained outer casing and diffusor designs from the original turbine design. In this paper, operational experience with an advanced Last Stage Blade coupled by damping elements is presented. In addition, the background leading to the development of this Last Stage Blade is outlined in this paper. Vibration measurement data obtained from field measurements in certain modernized units with retained outer casings from original installation is summarized and compared to the corresponding data for a freestanding Last Stage Blade previously used in these units showing the vibrational behavior of the newly developed Last Stage Blade. Results from field inspections are also presented. The data and inspections show the Last Stage Blade with damping elements do not exhibit elevated vibrations previously indicated.

Troubleshooting Turbine Steam Path Damage

2002 ◽  
Author(s):  
Thomas McCloskey
Keyword(s):  
Power Generation ◽  
Fossil Fuel ◽  
Failure Mechanisms ◽  
Economic Loss ◽  
Primary Objective ◽  
Steam Turbines ◽  
Utility Industry ◽  
Root Cause ◽  
Efficiency Losses

Steam path damage, particularly of rotating and stationary blading, has long been recognized as a leading cause of steam turbine unavailability for large fossil fuel plants worldwide. Turbine problems cost the utility industry as much as one billion dollars per year. Failures of blades, discs, and rotors in both fossil and nuclear steam turbines, represent a serious economic loss of availability and reliability for electric power generation suppliers and other energy supplies worldwide. Turbine problems such as deposition and erosion of blades can result in severe efficiency losses, resulting in significant economic penalties. The primary objective of this paper is to provide a methodology to identify the underlying damage or failure mechanisms, determine the root cause, and choosing immediate and long-term actions to lessen or prevent recurence of the problem.

Aerodynamic Optimization of the Nozzle for the Last Stage of Steam Turbine

2015 ◽  
Author(s):  
Aleš Macálka ◽  
Jaroslav Synáč ◽  
Jana Váchová ◽  
Miroslav Hajšman
Keyword(s):  
Design Process ◽  
Energy Demand ◽  
Cfd Simulation ◽  
Latin Hypercube Sampling ◽  
Optimized Design ◽  
Steam Turbines ◽  
Aerodynamic Optimization ◽  
Transient Time ◽  
Low Pressure Turbine ◽  
Last Stage

In order to meet the requirements of rising energy demand, one goal in the design process of modern steam turbines is to achieve high efficiencies. A major gain in efficiency is expected from the optimization of the last stage of a low pressure turbine (LP). This paper focuses on aerodynamic study by compound lean, axial sweep and hub end-wall of nozzle. The objective function is to maximize efficiency and minimize the leaving losses under the assumption of constant mass flow rate. The aerodynamic design process involves commercial 3D CFD tools. The maximization of the objective functions is achieved by means of a Design of Experiment (DoE) method “Optimal Space Filling” based on “Latin Hypercube Sampling”. Finally, the optimized design is analyzed by a transient (Time Transformation) CFD simulation. Furthermore, the detailed flow pattern of the optimized and the initial design is analyzed and compared.

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