Influence of Advancements in Gas Turbine Control Systems on Gas Turbine and Combined-Cycle Performance Test Correction Curves

2011 ◽  
Author(s):  
Thomas P. Schmitt ◽  
Christopher R. Banares ◽  
Benjamin D. Morlang ◽  
Matthew C. Michael
Keyword(s):  
Control System ◽  
Boundary Conditions ◽  
Control Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Performance Test ◽  
Combined Cycle ◽  
Plant Performance ◽  
Control Algorithms ◽  
Technical Accuracy

Many modern power plants feature gas turbines with advanced control systems that allow a greater level of performance enhancements, over a broader range of the combined-cycle plant’s operating environment, compared to conventional systems. Control system advancements tend to outpace a plant’s construction and commissioning timescale. Often, the control algorithms and settings in place at the final guarantee performance test will differ significantly from those envisioned during the contract agreement phase. As such, the gas turbine’s actual performance response to changes in boundary conditions, such as air temperature and air humidity, will be considerably different than the response illustrated on the initial correction curves. For the sake of technical accuracy, the performance correction curves should be updated to reflect the as-built, as-left behavior of the plant. By providing the most technically accurate curves, the needs of the new plant performance test are satisfied. Also, plant operators receive an accurate means to trend performance over time. The performance correction curves are intended to provide the most technically accurate assurance that the corrected test results are independent of boundary conditions that persist during the performance test. Therefore, after the gas turbine control algorithms and/or settings have been adjusted, the performance correction curves — whether specific to gas turbines or overall combined-cycle plants — should be updated to reflect any change in turbine response. This best practice maintains the highest level of technical accuracy. Failure to employ the available advanced gas turbine control system upgrades can limit the plant performance over the ambient operating regime. Failure to make a corresponding update to the correction curves can cause additional inaccuracy in the performance test’s corrected results. This paper presents a high-level discussion of GE’s recent gas turbine control system advancements, and emphasizes the need to update performance correction curves based on their impact.

Model Based Performance Correction Methodology — A Case Study

2014 ◽  
Author(s):  
Koldo Zuniga ◽  
Thomas P. Schmitt ◽  
Herve Clement ◽  
Joao Balaco
Keyword(s):  
Control System ◽  
Control Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Performance Test ◽  
Test Results ◽  
Model Based ◽  
Test Conditions ◽  
Partial Load

Correction curves are of great importance in the performance evaluation of heavy duty gas turbines (HDGT). They provide the means by which to translate performance test results from test conditions to the rated conditions. The correction factors are usually calculated using the original equipment manufacturer (OEM) gas turbine thermal model (a.k.a. cycle deck), varying one parameter at a time throughout a given range of interest. For some parameters bi-variate effects are considered when the associated secondary performance effect of another variable is significant. Although this traditional approach has been widely accepted by the industry, has offered a simple and transparent means of correcting test results, and has provided a reasonably accurate correction methodology for gas turbines with conventional control systems, it neglects the associated interdependence of each correction parameter from the remaining parameters. Also, its inherently static nature is not well suited for today’s modern gas turbine control systems employing integral gas turbine aero-thermal models in the control system that continuously adapt the turbine’s operating parameters to the “as running” aero-thermal component performance characteristics. Accordingly, the most accurate means by which to correct the measured performance from test conditions to the guarantee conditions is by use of Model-Based Performance Corrections, in agreement with the current PTC-22 and ISO 2314, although not commonly used or accepted within the industry. The implementation of Model-based Corrections is presented for the Case Study of a GE 9FA gas turbine upgrade project, with an advanced model-based control system that accommodated a multitude of operating boundaries. Unique plant operating restrictions, coupled with its focus on partial load heat rate, presented a perfect scenario to employ Model-Based Performance Corrections.

Short-Term Optimization of a Combined Cycle Power Plant Integrated With an Inlet Air Conditioning Unit

2020 ◽  
Author(s):  
Weimar Mantilla ◽  
José García ◽  
Rafael Guédez ◽  
Alessandro Sorce
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Air Conditioning ◽  
Combined Cycle ◽  
Plant Performance ◽  
Mixed Integer ◽  
Environmental Load ◽  
Turbine Inlet ◽  
The Impact

Abstract Under new scenarios with high shares of variable renewable electricity, combined cycle gas turbines (CCGT) are required to improve their flexibility, in terms of ramping capabilities and part-load efficiency, to help balance the power system. Simultaneously, liberalization of electricity markets and the complexity of its hourly price dynamics are affecting the CCGT profitability, leading the need for optimizing its operation. Among the different possibilities to enhance the power plant performance, an inlet air conditioning unit (ICU) offers the benefit of power augmentation and “minimum environmental load” (MEL) reduction by controlling the gas turbine inlet temperature using cold thermal energy storage and a heat pump. Consequently, an evaluation of a CCGT integrated with this inlet conditioning unit including a day-ahead optimized operation strategy was developed in this study. To establish the hourly dispatch of the power plant and the operation mode of the inlet conditioning unit to either cool down or heat up the gas turbine inlet air, a mixed-integer linear optimization (MILP) was formulated using MATLAB, aiming to maximize the operational profit of the plant within a 24-hours horizon. To assess the impact of the proposed unit operating under this dispatch strategy, historical data of electricity and natural gas prices, as well as meteorological data and CO2 emission allowances price, have been used to perform annual simulations of a reference power plant located in Turin, Italy. Furthermore, different equipment capacities and parameters have been investigated to identify trends of the power plant performance. Lastly, a sensitivity analysis on market conditions to test the control strategy response was also considered. Results indicate that the inlet conditioning unit, together with the dispatch optimization, increases the power plant’s operational profit by achieving a wider operational range, particularly important during peak and off-peak periods. For the specific case study, it is estimated that the net present value of the CCGT integrated with the ICU is 0.5% higher than the power plant without the unit. In terms of technical performance, results show that the unit reduces the minimum environmental load by approximately 1.34% and can increase the net power output by 0.17% annually.

Development of an Interactive Code for Design and Off-Design Performance Evaluation of Gas Turbines

2009 ◽  
Author(s):  
Behnam Rezaei Zangmolk ◽  
Hiwa Khaledi
Keyword(s):  
Control System ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Design Performance ◽  
Blade Cooling ◽  
Constant Control ◽  
Model Component ◽  
Surge Line ◽  
Cooling Model

In this paper, development of a modular code for simulation of design and off-design performance of different gas turbines (with different shafts and technology) has been described. This interactive code will be used for different purposes in MPG Company. This turbomachinery and thermodynamic model is based on compressor and turbine maps and blade cooling has been considered with a cooling model. Component maps and effect of IGV have been developed from one of 1D, 2D or Q3d in-house codes. It is demonstrated that this model is accurate for prediction of gas turbine behavior at both design and off-design conditions. Effect of various control system — IGV constant, TIT constant and TET constant — is evaluated. These results show that IGV constant control system has the highest and TIT constant have the lowest efficiency for a simple cycle gas turbine. In contrast, the reverse is true in a combined cycle. Also the results show that the compressor is the most stable and away enough from surge line with IGV constant control system and has the highest efficiency.

Gas Turbine Common Issues, Failure Investigations, Root Cause Analyses, and Preventative Actions

2016 ◽  
Author(s):  
Stephen Garner ◽  
Zuhair Ibrahim
Keyword(s):  
Control System ◽  
Internal Combustion Engine ◽  
Control Systems ◽  
Gas Turbine ◽  
Failure Mode ◽  
Gas Turbines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
System Availability ◽  
Root Cause

Gas turbines are a type of internal combustion engine and are used in a wide range of services powering aircraft of all types, as well as driving mechanical equipment such as pumps, compressors in the petrochemical industry, and generators in the electric utility industry. Similar to the reciprocating internal combustion engine in an automobile, energy (mechanical or electrical) is generated by the burning of a hydrocarbon fuel (i.e., jet fuel, diesel or natural gas). The core of a gas turbine engine is comprised of three main sections: the compressor section, the combustor section, and the turbine section. To ensure that a gas turbine operates safely, reliably, and with optimum performance, all gas turbines are provided with a control system designed either by the OEM or according to the OEM’s specification. The OEM-provided control systems will typically include complex and integrated subsystems such as (but not limited to): a graphic user interface, an engine management system (EMS or ECS), a safety related system (SRS), and a package control system (PCS) that may interface with a facilities’ existing computerized control systems. Any failure of the mechanical systems, electro-mechanical systems, or logic based control systems of a gas turbine can result in forced outage. A forced outage of a gas turbine, whether in a mechanical service, such as pipelines, or in either a simple cycle or combined cycle power generation installation results in a reduction of system availability and therefore a loss in revenue. The significant capital investment in a gas turbine system necessitates a high degree of reliability and system availability while reducing forced outages. A power plant can minimize occurrences of forced outages and optimize recovery of capacity by effectively combining proactive and reactive solutions. This paper will discuss both proactive and reactive programs as well as their implementation in order to answer the key questions that often surround an outage: How is outage time minimized while increasing reliability and system availability? What went wrong and who or what is responsible? How soon can the unit or the plant get back online? And what operational or maintenance considerations are needed to prevent a similar recurrence. Proactive approaches to be discussed include process hazard analyses (PHA) such as hazard and operability studies (HAZOP), hazard identification (HAZID), layer-of-protection analyses (LOPA), what-if analyses, and quantitative risk assessments (QRA) in addition to failure mode and effects analysis (FMEA); and failure mode, effects and criticality analysis (FMECA). Reactive approaches to be discussed include various root cause analysis (RCA) and failure analysis (FA) techniques and methodologies such as fault-tree analysis. Case studies and some lessons learned will also be presented to illustrate the methods.

scholarly journals Fuel Control of Gas Turbines by Programmable Logic Controllers

1993 ◽  
Author(s):  
Dan A. King
Keyword(s):  
Control System ◽  
Natural Gas ◽  
Control Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Programmable Logic Controller ◽  
Programmable Logic ◽  
Programmable Logic Controllers ◽  
Control Functions ◽  
Logic Controllers

NOVA Corporation of Alberta has developed a programmable logic controller based gas turbine fuel control system for natural gas compressor set applications. The system carries out all necessary fuel control functions and was integrated into the existing programmable logic controller used for sequencing and shutdown. The system has been successfully implemented on several different aero derivative gas turbines to date. This paper discusses the development of the system, its performance and advantages over standalone hardware-based fuel control systems typically used in the application.

Development of a Combined Cycle Gas Turbine/Steam Plant for Training Marine and Power Engineers

2007 ◽  
Author(s):  
W. Peter Sarnacki ◽  
Richard Kimball ◽  
Barbara Fleck
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Power Industry ◽  
Combined Cycle ◽  
Plant Performance ◽  
Engineering Programs ◽  
Hands On ◽  
Steam Plant

The integration of micro turbine engines into the engineering programs offered at Maine Maritime Academy (MMA) has created a dynamic, hands-on approach to learning the theoretical and operational characteristics of a turbojet engine. Maine Maritime Academy is a fully accredited college of Engineering, Science and International Business located on the coast of Maine and has over 850 undergraduate students. The majority of the students are enrolled in one of five majors offered at the college in the Engineering Department. MMA already utilizes gas turbines and steam plants as part of the core engineering training with fully operational turbines and steam plant laboratories. As background, this paper will overview the unique hands-on nature of the engineering programs offered at the institution with a focus of implementation of a micro gas turbine trainer into all engineering majors taught at the college. The training demonstrates the effectiveness of a working gas turbine to translate theory into practical applications and real world conditions found in the operation of a combustion turbine. This paper presents the efforts of developing a combined cycle power plant for training engineers in the operation and performance of such a plant. Combined cycle power plants are common in the power industry due to their high thermal efficiencies. As gas turbines/electric power plants become implemented into marine applications, it is expected that combined cycle plants will follow. Maine Maritime Academy has a focus on training engineers for the marine and stationary power industry. The trainer described in this paper is intended to prepare engineers in the design and operation of this type of plant, as well as serve as a research platform for operational and technical study in plant performance. This work describes efforts to combine these laboratory resources into an operating combined cycle plant. Specifically, we present efforts to integrate a commercially available, 65 kW gas turbine generator system with our existing steam plant. The paper reviews the design and analysis of the system to produce a 78 kW power plant that approaches 35% thermal efficiency. The functional operation of the plant as a trainer is presented as the plant is designed to operate with the same basic functionality and control as a larger commercial plant.

Gas Turbine Part Load Exhaust Gas Emissions Turndown Envelope Testing Methodology

2009 ◽  
Author(s):  
Kristen LeClair ◽  
Thomas Schmitt ◽  
Garth Frederick
Keyword(s):  
Control System ◽  
Gas Turbine ◽  
Fuel Consumption ◽  
Gas Turbines ◽  
Thermodynamic Simulation ◽  
Combined Cycle ◽  
Exhaust Gas ◽  
Ambient Conditions ◽  
Gas Emissions ◽  
Exhaust Gas Emissions

Economic and regulatory requirements have transformed today’s power plant operations. High reserve margins and increased fuel costs have driven combined cycle plants that were once dispatched primarily at base-load to be cycled off during off-peak hours. For many plants, the increased cycling has contributed to shorter maintenance intervals and higher overall operating costs. Technology advancements in combustion system design and in gas turbine control systems has led to extensions in the emissions-compliant operating window of gas turbines, also known as turndown. With extended turndown capability, customers are now able to significantly reduce fuel consumption during minimum load operation at off-peak hours, while simultaneously minimizing the number of shutdowns. Extended turndown reduces operational costs by offsetting the fuel consumption costs against the costs associated with starting up and the maintenance costs associated with such starts. Along with the increased emphasis on turndown capability, there has been a rising need to develop and standardize methods by which turndown capability can be accurately measured and reported. By definition, the limiting factor for turndown is the exhaust gas emissions, primarily CO and NOx. A concurrent and accurate measurement of performance and emissions is an essential ingredient to the determination of turndown capability. Of particular challenge is the method by which turndown results that were measured at one set of ambient conditions can be accurately projected to a specific guarantee condition, or to a range of ambient conditions, for which turndown capabilities have been guaranteed. The turndown projection methodology needs to consider combustion physics, control system algorithms, and basic cycle thermodynamics. Recent advances in the integration of empirically tuned physics-based combustion models with control system models and the gas turbine thermodynamic simulation, has resulted in test procedures for use in the contractual demonstration of turndown capability. A discussion of these methods is presented, along with data showing the extent to which the methods have provided accurate and repeatable test results.

Hot Windbox and Combined Cycle Repowering to Improve Heat Rate

2010 ◽  
Author(s):  
Tarek A. Tawfik ◽  
Thomas P. Smith
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Heat Rate ◽  
The United States ◽  
Combined Cycle ◽  
Plant Performance ◽  
Ambient Conditions ◽  
North East

Retrofitting existing power generation plants by repowering is becoming an attractive option to improve plant performance with less cost. “Hot Windbox Repowering” involves utilizing the hot exhaust gas from a combustion gas turbine and using it as combustion air for an existing fossil-fuel boiler. “Combined Cycle Repowering” or “Full Repowering” involves completely replacing the existing boiler with a combined cycle consisting of a gas turbine(s) and a heat recovery steam generator (HRSG). The existing steam turbine will be used in both repowering scenarios. This paper discusses an engineering study and summarizes the results obtained from repowering an existing heavy-oil / natural gas fired steam power plant in the north east of the United States. The plant consists of a 600 MW boiler and steam turbine. Several engineering studies were considered and evaluated thermodynamically and economically to retrofit such plant. Several options were considered involving different gas turbines, gas turbine combinations, and different repowering methods. The best option is based on retrofitting the unit by a combination of both, hot windbox repowering and combined cycle repowering. The proposed design consists of one gas turbine repowering the windbox of the existing boiler, and a second gas turbine operating in a separate combined cycle configuration with the generated superheated steam tying into the main steam line and expanding in the existing steam turbine. Several heat balances were developed to assist in obtaining meaningful results for this feasibility study. Actual costs were obtained for the gas turbines and heat recovery steam generators (HRSG), as well as installation costs for a more accurate evaluation. The results indicate that the combined output of the repowered unit will generate an additional 295 MW and reduce the heat rate by more than 11 percent at full load and annual average ambient conditions. The estimated capital cost of the project is expected to range from $235 to $245 millions.

Development of a Programmable Logic Controller Based Fuel Control System for the G.E. LM-1600 Gas Turbine

1997 ◽  
Author(s):  
Dan A. King ◽  
Jim Patrick
Keyword(s):  
Control System ◽  
Control Systems ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Model Development ◽  
Performance Testing ◽  
Programmable Logic Controller ◽  
Pipeline System ◽  
Programmable Logic ◽  
General Electric

Nova Gas Transmission Ltd. (NGTL) has been developing integrated turbine fuel control systems since the late 1980s. This is part of a long term vision to completely integrate the control systems at its compressor stations. These systems are integrated into the “off the shelf” Programmable Logic Controller (PLC) used for unit sequencing and shutdowns. As part of this effort NGTL began development of a fuel control system for the General Electric LM-1600 gas turbines in 1993. These systems, now successfully in service, proved to be the most challenging to develop. NGTL uses gas turbine packages, eleven of which are LM-1600s, to drive the compressors used in its gas pipeline system. This paper includes some brief background reasons why NGTL has chosen to develop fuel control systems and describes in detail the development of the fuel control system for the LM-1600. Discussion of the control challenges of the LM-1600 includes fuel throttle valve and actuator selection and options, control system hardware and software development (consistent with the General Electric Installation Design Manual (IDM) requirements) and, engine model development. The model application, office testing, site performance testing and the static and dynamic test results are also discussed. The paper also describes NGTL’s future plan for installation of LM-1600 fuel control systems on its fleet.

A Sequential Approach for Gas Turbine Power Plant Preventive Maintenance Scheduling

2005 ◽  
Author(s):  
Yongjun Zhao ◽  
Vitali Volovoi ◽  
Mark Waters ◽  
Dimitri Mavris
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Preventive Maintenance ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Maintenance Scheduling ◽  
Plant Performance ◽  
Optimization Approach ◽  
Gas Turbine Power Plant

Traditionally the gas turbine power plant preventive maintenances are scheduled with constant maintenance intervals based on recommendations from the equipment suppliers. The preventive maintenances are based on fleet wide experiences, and they are scheduled in a one-size-fit-all fashion. However, in reality, the operating conditions for each gas turbine may vary from site to site, and from unit to unit. Furthermore, the gas turbine is a repairable deteriorating system, and preventive maintenance usually restores only part of its performance. This suggests the gas turbines need more frequent inspection and maintenance as it ages. A unit specific sequential preventive maintenance approach is therefore needed for gas turbine power plants preventive maintenance scheduling. Traditionally the optimization criteria for preventive maintenance scheduling is usually cost based. In the deregulated electric power market, a profit based optimization approach is expected to be more effective than the cost based approach. In such an approach, power plant performance, reliability, and the market dynamics are considered in a joint fashion. In this paper, a novel idea that economics drive maintenance expense and frequency to more frequent repairs and greater expense as the equipment and components age is introduced, and a profit based unit specific sequential preventive maintenance scheduling methodology is developed. To demonstrate the feasibility of the proposed approach, this methodology is implemented using a base load combined cycle power plant with single gas turbine unit.

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