The power industry is increasingly affected by several trends, which require improvements in the distributed generation and control systems of on-site power. These trends include the ability to share load across generators more effectively, seamless sequencing of generators, and the ability to monitor and control power that is being produced. Electronic control systems can provide these advantages in a cost effective solution. The application of electronic controls to a power distribution system requires a thorough development program. It is imperative to assure that the controls will provide reliable, long-term performance, as well as meeting the plant’s current and future needs for power distribution. This paper describes the development and field evaluation required to apply electronic controls to existing switchgear and power distribution systems in the power generation industry. The microprocessor based electronic control system for today’s power plants replaces out-dated analog equipment and antiquated relay logic. The new systems incorporate three main functions: Paralleling generators, monitoring power requirements, and effective sequencing of generators in power plants. Integration of these functions into the microprocessor based control system provides increased reliability, reduced cost, and enhanced performance, while concurrently providing increased flexibility in the operation of the plant. Additional benefits can be realized including reduced operator requirements, reduced training costs, and reduced burden on instrumentation electricians. A primary focus of this paper is the process used to qualify the control system needed for specific types of existing distributed power systems. This process consists of current system evaluation and categorization, establishment of classification of plant (utility, merchant plant, peak shaving facility, IPP), and determining the future needs of individual plants for power distribution. Local regulatory and utility protection and interconnect requirements must also be assessed to assure that the new control system meets or exceeds them. Methods of accurately monitoring, improving performance, and providing generator sequencing are defined, including accounting for improvements in the long-term expansion of the distributed power control and monitoring system.

Upon return to service from a refueling outage, the 1150 MW SONGS Unit 3 was at 39% reactor power when a circuit breaker fault resulted in a fire, a partial loss of AC off-site power, and a reactor shutdown. The failure of a circuit breaker to function properly resulted in the unavailability of the DC driven turbine emergency lubricating oil pump, causing extensive damage to the turbine generator. The power supply crisis in California at this time highlighted the need for an urgent understanding of the seriousness of the damage to the turbine generator, the consequences for the repair and timely return of the unit to service. Initial inspections indicated that all rotor line bearings had suffered from loss of white metal and most of the housings were distorted. Rotor journals were scored from solid contact and subject to excessive heat damage. Rotor steam seals had suffered rubbing damage. In view of the component sizes associated with such a large machine, and the need to minimize the outage duration, a large proportion of the repair work was undertaken on site. This enabled SCE to project manage the work themselves ‘in-house’. It was decided that the HP and the three LP turbine rotors would remain on site, with only the Generator rotor and the complete Exciter being shipped to the OEM’s workshops for repair. Specialist sub-contractors were employed for site machining and heat treatment. Consultants were hired for specialist technical matters, primarily related to metallurgical issues, to complement the in-house expertise of both SCE and ALSTOM. The serious nature of the damage required close cooperation between SCE and ALSTOM the OEM. It was important to understand the design margins and therefore the scope for repair, and long term integrity of the solutions. The detailed repair instructions were prepared and controlled jointly between ALSTOM and SCE engineers on site, with extensive technical back-up provided from the OEM engineering design departments. Similar close co-operation on the re-design of components and fast track supply of spare parts was crucial to the success of the project.

There is growing pressure to reduce the pay back period of major capital expenditures, and in most cases, revamping existing turbomachinery provides more attractive economics than new equipment. Moreover, revamping existing power generation equipment with modern technology mitigates the expenses associated with obtaining new environmental licensing. Today, innovative application of technological advancements in mechanical and aero-thermodynamic design/analysis methods combined with new manufacturing methods is yielding significant performance improvements. This paper details the revamping of a 36 MW generator-drive turbine that resulted in an eleven point improvement in steam rate. Details of the steampath thermodynamic design/ analysis methods, sealing, diaphragm construction, blade design and low-pressure steam path design, etc. are presented.

The power industry generates more data than any other. The trick is collecting all of this data, down to the sub-second, storing it and making it accessible — in real time — to those who need it, when they need it for advanced decision making. This includes everyone from those on the power plant floor and executive offices to the buyers and sellers of power. Clearly integration is critical. Increasingly, utilities and large corporate power users are learning how to harness that data to capture true value. This is especially important when deregulation and rising utility costs are putting power generating companies under a microscope, forcing them to be accountable to their boards, stockholders and the public. Power generators are increasingly relying on data historians to gather information in real-time for performing trend reporting, predictive maintenance functions and optimizing overall operational efficiency.

The scope was straight forward; design and install a complete SCADA system to automate as much as reasonably possible the utility plant consisting of: • One gas turbine cogeneration unit with duct firing, • Three reciprocating engine generators, • Two utility sources, • Three Absorption chillers, • Four electric chillers, • Two duel fuel boilers, and • 2 cooling towers. Prior to this project, the entire utility plant was operated manually. This included everything from chiller loading to Power Factor control.

In the modern scenario of energy systems, we see that the efficiency of the modern day power plants attain a maximum possible limit of 40%–50% in most cases. This is a result of the wastage’s that are prevalent in the systems in the form of heat loss, friction losses due to flow in pipes and flow in other units. The modern day power plants employ the Heat Recovery Steam Generators ( HRSG) which help in converting the waste heat coming out of the turbine into useful work, thus increasing the overall efficiency of the plant. The application of Gas turbine generator (GT) based co-Generation power plants as a part of the industrial plants is on the rise. These plants are required to meet the industrial plants power and steam demand with variations associated with it. This paper deals with the study of a versatile industrial HRSG with specifications in order to support the design. The study and design is based on the design and production unit “Babcock Borsig power systems”, Chennai, India. The paper focuses on the Heat recovery Steam Generator design inclusive of selecting the parameters like pressure of steam, velocity of fluids at different stages with respect to the conditions, material selection etc. The design of HRSG involves primary inputs such as the Engineering Flow diagrams, Arrangement of Equipment’s at proper elevation and Engineering data (Specifications). The considerations of line sizing with respect to pressure drop, Net positive Suction Head, Pipe line erosion, Water Hammer and noise are taken into account. A well-specified and designed HRSG can substantially help the Industrial Co-Generation plant to meet the demand variation and imbalances without sacrificing the reliability of operation. The study is an important contribution to the exponentially rising population and hence the energy demands in the world.

An innovative small-scale gasification system for solid wastes is proposed which is known as STAR-MEET system. In this system, a fixed-bed pyrolyzer combined with a high temperature reformer using high temperature steam/air mixture is employed. From the experimental results using rubber chips as a fuel, it has been demonstrated that injection of high temperature steam/air mixture into the pyrolysis gas effectively decomposes tar and soot components in the pyrolysis gas into CO and H 2 , and almost dust and tar free clean reformed gas can be generated. The STAR-MEET system requires high temperature steam/air generator, and a 900C class metallic type compact heat exchanger has been successfully developed. This gasification system generates low BTU gas from solid wastes. Thus power generation experiments using a dual fueled (light oil gas and low BTU gas) small diesel engine were done using a simulated low BTU gas produced from natural gas diluted with nitrogen. Compared with light oil only driven, dual fueled engine shows similar thermal efficiency while significantly low NOx emission. Finally, power generation experiments using a complete STAR-MEET plant has been successfully done. These results demonstrates small-scale gasification and power generation system using solid wastes is quite feasible.

The output capacity of combined cycle power plants is reduced in many cases, and sometimes forced to outages, when its main components are affected by faults, i.e., when the rotating equipment such as turbines, generators, compressors, pumps and fans suffer a failure. Normally, the overall reduction of the efficiency, and sometimes the component efficiencies, is monitored but it is difficult to identify the primary causes of the fault of the specific equipment that causes the reduction of plant efficiency. Therefore, to reduce the time of faulty operation, a precise diagnostic tool is needed. One such tool is an expert system approach, which is presented in this work. It consists of several expert systems for the identification of the faults caused by deterioration of the inner parts of the equipment, Fig. 1. Such faults not only reduce the plant efficiency but in many cases also increase the vibrations of the rotor-bearing system. Based on knowledge, the various expert systems have been constructed and their algorithms (efficiency reduction) developed for the following equipment: steam turbines, gas turbines and compressors, condenser, pumps and water cooling system. An expert system for detecting faults that increase the vibration of the rotor–bearing system is also presented. As far as the turbo compressor expert system is concerned the fault hybrid patterns previously developed were implemented and described elsewhere [1].

The fossil fuel depletion and the CO 2 warming due to the combustion are becoming serious environmental issues. Therefore, alternative energy systems minimumizing fossil fuels dependence are now required to be developted. Hydrogen is a best candidate for alternative energy sources friendly to the environment, but the essential point is how we produce hydrogen, independently of fossil fuel with a minimum energy input. This work aims first at proposing an alternative hydrogen gasifier from acid water by immersing ionicity metals, and second at applying the gasifier to a hydrogen ultra micro gas turbine electric generator charger system to construct hydrogen self supply energy system. First, D 2 SO 4 as acid aqueous solutions and (Zn+Cu) and Zn plates as ionicity metals electrodes are selected here for H 2 gasifier. The hydrogen production rate is experimentally characterized by changing the pH and temperature of the solution and the metal surface area. The gasifier has a good performance of hydrogen production of about 18 l/min at 60°C per unit electrode area under the pH = ∼1.0. This flow rate increases almost linearly to the acid temperature. In addition, the zinc resolved into the acid water, ZnSO 4 in the case of D2SO4 for example, is able to be easily recrystalized on the electrode by reasonable electricity input of ∼2.5V. Second, the produced hydrogen is applied to ultra micro turbo electric generator / charger as hydrogen self supply system. This smart system is well applicable to hydrogen electric car, because of an ideal power source having small size, lightweight, low vibration, early start, no NO X and CO 2 emissions, very low fuel consumption, long trip, etc. In the experiment a car turbo charger is converted into a compressorturbine system, and a high revolution electricity generator is connected to the turbo system. A combustor is designed for very low hydrogen consumption by ultra lean burning which causes almost no NO X emission due to low temperature < 1000°C. The turbo system is tested, resulting in a high efficiency, in spite of its small size, enough to generate electricity for charging a battery of electric car. By using these two elements, we aim to construct HSSES (Hydrogen Self Supply Energy System) which is found to be attractive especially for small electric cars and home cogenerations.

Generators require cooling typically provided by one or two shaft driven rotating fans. These fans see large operating stresses due to rotational forces, shrink fit pressures, axial thrust forces, and thermal stress. Over time, fatigue cracks can develop in either the fan blade or root area, potentially leading to a catastrophic failure. Failure of a rotating fan inside a generator will cause extensive damage. The stored rotational energy in a fan that lets loose will typically destroy the stator winding, sometimes damage the stator core, and cause other damage to rotor components such as retaining rings, the rotor winding and possibly, even the rotor forging. This paper will be useful to power plant owners who have to maintain plant equipment and prevent failures of that equipment. A good understanding of the possible failure modes associated with rotating fans will enhance the emphasis on conducting good inspections of this equipment.

This paper is an additional report to the paper by Amano (2001). In this paper, the authors report the additional experimental results of the effect of an ammonia mass fraction at the inlet of the AWM (Ammonia-Water Mixture) vapor generator in the AWM turbine system. The AWM turbine system features the Kalina Cycle technology. The 70KW-experimental facility was built in order to gain knowledge for practical applications. The heat source is the exhaust steam from a back-pressure steam turbine. The AWM turbine system is installed at the bottoming stage of a combined cycle which has a gas turbine, a steam turbine and an AWM turbine for cascade utilization of heat. The authors designed and constructed an experimental facility, the ACGS (the Advanced Co-Generation System), to investigate various energy-saving technologies for a distributed energy supply system in the Advanced Research Institute for Science and Engineering at Waseda University. One of the main targets is a hybrid combined heat and power supply system that uses AWM as its working fluid. The AWM turbine system was developed for the bottoming stage of a “trinary turbine cycle system” which is composed of a gas turbine, a steam turbine and the AWM turbine systems. The experimental results of the ammonia mass fraction to the cycle efficiency are investigated with a range of the ammonia mass fraction between 0.4 [ NH3 kg/kg] to 0.7 [ NH3 kg/kg]. It shows that there are optimal operating conditions depending on the heat source temperature with an ammonia mass fraction of the cycle. The simulation model of the AWM turbine system shows good agreement with the experimental data.

Microturbine generators have shown good perspectives for small scale distributed generation. In Brazil, the Thermal Systems Study Group of Federal School of Engineering of Itajuba´, sponsored by the CEMIG (Electrical Utility of Minas Gerais), is developing a project about experimental evaluation of microturbines systems. The objective of this paper is to evaluate the cost of generating electricity with microturbines and show the emissions range of microturbines operating with natural gas. The cost of the microturbine generators as well as the cost of the electricity and natural gas in Brazil at this moment and the projection for the future were considered.

It is well known that one of the necessities of designing very tall buildings is the need to control the internal and external airflows through the building. Presently, air flow control is required for maintaining proper ventilation for not only the occupants at 15–25 cfm per person (ref. 1) but also the electrical equipment generates heat at approx. 0.8 cfm/sq.ft. (ref. 2) for 2 to 3 W/ft 2 (ref. 3). It is also well known that a 1,000+ ft. conduit (for example, an elevator shaft or an utility air chase within a skyscraper) extending into the atmosphere will have its top opening at lower atmospheric pressure and temperature than the opening at ground level. The difference is caused by the differences in the weight of the high air columns. For example, the air conditioning within the building includes considerable waste energy (albeit very low grade energy) from the building’s HVAC system. Increasing the air temperature, decreases the density of the air column achieves the desired effect: that of establishing more of a pressure differential across the inlet and outlet of the pneumatic conduit. The addition of heat certainly is energy consumption unless, as the disclosure claim states, it can be recovered from the building’s otherwise wasted energy sources. An alternative method for establishing a significant pressure differential would be to use a rather large pneumatic-ejector device on the top of the building that utilizes the Bernoulli effect to draw air upward, through the air conduit, using the high velocity air streams that are prevalent at those altitudes. If a pressure differential can be maintained then a continuous airflow (cfm) will be induced through such a conduit. A continuous air flow rate, and not one that is effected by land based obstacles or the sun’s heating and cooling of low level air masses, is ideal for generating a consistent level of electric power. This phenomenon has not been utilized for power generation. For a skyscraper, the conduits are ready-made: the under-utilized elevator columns or air chases. For this study the power generation from Pneumatic Column Power Recovery can also include free standing towers that can collect solar energy or even naturally occurring structures such as very deep mountainous chasms that could serve as a natural air draft. This paper will present an analysis of using wind-columns that are over 1,000 ft. tall together to generate power with state-of-the art wind turbine generators. The paper will conclude with a very bold, some would say: fanciful suggestion, that such power generation opportunities are available in enormous magnitudes if the formulations presented here are extended to man-made and natural geo-physical phenomenon that can be gargantuan in stature and thus produces a proportional increase in power recovery opportunity.

Alstom has developed a monitoring and optimization system to offer the power plant an integrated maintenance and diagnosis system. This system is capable of monitoring all Alstom machines and processes in a combined cycle power plant: the gas turbine, steam turbine, generator, HRSG, and cooling system. All data archived in a central database server. Any personal computer networked with the server can display the process data and calculated results. To limit the scope of current paper, only the gas turbine monitoring and diagnostic module is presented. The system concept, configuration, and the environment of gas turbine module as well as capability will be discussed in this paper. The Gas Turbine Module (GTM) provides continuous monitoring of the GT process and continuous displaying of certain calculated results. The GTM provides a tool aimed to help the operator to make decisions, which affect efficiency, reliability and damage control. The monitoring areas include combustion stability (pulsation analysis), exhaust temperature distribution, compressor fouling and surge margin, and thermal performance. Furthermore, the GTM can provide the thermodynamic variables at the gas turbine exhaust for other applications in the combined cycle calculation. The implementation of this module is based on the users’ requirements to optimize the operation, to increase plant reliability and availability, and to optimize equipment performance. The GTM is a PC-based monitoring and diagnostic system. A guiding principal is that the retrofit of the GTM should have minimal impact on the gas turbine control system. This is the reason the system is PC based. A remote connection can be made via network. Users can access and see all real time and historical data by means of a networked computer. The real key success of the GTM is to be able to detect an early component failure and abnormalities during normal plant operation. Therefore, this information can be used for plant management, production forecast, equipment maintenance, and part replacement decision strategy.

Industrial burners provide process heat for a wide range of applications including cogeneration power production. In such applications a (typically) natural gas fired stationary turbine powers an electric generator and indirectly powers a heat recover steam generator (HRSG). The HRSG steam cycle operates by reclaiming the residual thermal energy of the gas turbine exhaust (GTE) flow. Burners are used to reheat the GTE and increase plant capacity during peak demand periods. CFD modeling is used in the design of burner systems for HRSG applications. GTE flow exiting the turbine unit is passed through a diffuser and then expanded into ductwork where the steam system heat exchangers are located. The expansion of the GTE flow from the turbine diffuser to the full cross section of the ductwork is usually severe and creates an uneven flow distribution. Flow correcting structure may be needed to distribute the flow depending upon the severity of the duct expansion. CFD modeling is used to predict the flow distribution of the GTE and guide the design of any necessary flow correcting structure. Burners are typically installed in an array upstream of the application heat exchanger inlet. CFD combustion, heat transfer, and flow analysis is employed in the burner system design process to locate the burner array, determine any necessary flow baffling, and to ensure and provide a uniform thermal distribution at the downstream heat exchanger inlet. Excessive thermal variation in the GTE flow entering the heat exchanger results in large temperature gradients that can lead to thermal cracking and fatigue of the heat exchanger surfaces. CFD modeling is used to ensure that the burner system design produces a uniform flow and temperature distribution at the heat exchanger inlet region downstream of the burners. This report presents a case study of a CFD flow, heat-transfer, and combustion analysis for a typical HRSG burner application. Two CFD models were constructed for the analysis. The first model included the coupled effects of flow, heat transfer, and combustion for the entire HRSG model volume, but excluded the effects of thermal radiation. The second model included a sub-domain of the HRSG volume near the burner and included the additional effects of thermal radiation, both surface radiation and the effects of the radiatively participating flue gas. Radiative effects were included in the second model by employing the Discrete Transfer Method. Results of the study showed the significant role thermal radiative heat transfer had on the resulting temperature predictions downstream of the flame zone.

This paper examines the conversion of a GE 7FA from generating 60 Cycle power to 50 Cycle power. The turbine is nominally rated for a 60-cycle ISO output of 175 MW. With the gas turbine boom of the late 1990s and then the cancellation of several GT based projects, a surplus of GTs has been created. Owners of these GTs have been reviewing alternative options for installation at another of their plants or resale of their GTs to another user. One potential solution is the conversion of a GT into a 50-cycle machine for installation in other markets around the world. If this type of conversion proves feasible, it also opens the door for the 60-cycle designed GTs to be marketed overseas to compete with original 50-cycle equipment. Three potential options for creating 50 Cycle power with a 7FA were identified: 1. Operate the Combustion Turbine Generator (CTG) at 3000 RPM to generate energy at 50 Hz. 2. Operate the CTG at 3600 RPM to generate energy at 60 Hz with the installation of an invertor, external to the CTG, to convert 60 Hz potential to 50 Hz. 3. Operate the turbine at 3600 RPM and the generator at 3000 RPM by installing a gearbox (speed reducer) between the turbine and the generator. These three options were researched and pricing was obtained on those that were considered feasible. The turbine OEM, GE, was also contacted to provide input on each of the scenarios. The results for each of the options are as follows.

This paper describes the performance and operating experience with two residential sized Combined Heat and Power units which were in operation from 1979 through 1995. The first unit was an automatic coal fired steam electric Combined Heat and Power system, based on the Rankine Steam Cycle. The unit was initially fired in 1979, operating with a steam turbine-generator for two years, and was modified with a reciprocating expander for an additional two years operation. The unit functioned reliably, with only four forced outages during the four years of operation. The second system was diesel engine-generator based, again a Combined Heat and Power System, which was started in 1987 and operated for seven seasons into 1995. The system efficiency averaged 90% during the heating season, and showed remarkably low machinery wear and minimal maintenance during the eight year run. A technical description and performance characteristics are provided for each unit. Relevant design features, design challenges arising during operation, and details of operating experiences are discussed. Photographs, System Diagrams, and Performance Graphs of these early prototype units are included within the paper. Recommended design criteria for optimized small Distributed Generation/Combined Heat and Power units is developed in the paper.

By passing the combustion gases through magnetic field, magneto generator converts heat directly to electric power without moving parts. The inherent characteristic of high efficiency and low emission makes Coal fired MHD power generation technology attractive to be a potential alternative power generation method in the future. This paper presents the working principle of MHD generator and describes the coal fired MHD power plant systems and the key components in these systems. It also reviews the batch research of Department of Energy on coal fired MHD electric power generation—Proof of Concept Program from 1987 to 1993 and states some challenges remained on its way to commercial use.

Based on field-tested performance and third-party evaluations, Beacon Power has demonstrated that high-energy flywheel systems are a sustainable energy storage option for many electrical applications. Successful power quality implementations range from low-power telecommunications equipment (low-kW for hours) to high-power industrial support (hundreds of kW for seconds). Using this proven technology, Beacon Power has begun development of a modular, high-energy system to deliver robust and responsive megawatt output levels — for seconds, minutes and even hours. This flywheel energy matrix would be ideal for grid stabilization, spinning reserves, renewable power, and distributed resource applications. For example, a system such as this would have sufficient energy to provide the minutes needed for ride-through capability to start smaller gas turbine-powered generators. This paper describes thc tecchnical feasibility of combining thc best features of flywheel energy storage with standard high-power electronics for energy storage and delivery. Two system-level configuration options are discussed: 1) Fixed installations, comprising a matrix of flywheels installed in a building with the Power Conversion System (PCS); and, 2) Deployable, portable equipment, based on a system-modular approach comprising an array of flywheels and PCS packaged in a standard shipping container to be easily dispatched for grid stabilization or load support. The technical discussion includes a building block-level component description of the flywheel and its motor/generator drive, electrical ratings, mechanical ratings and more. At a system level, an overview of component interconnection is provided, including links to the PCS. In addition, footprint and weight values are illustrated for both proposed system configuration options. This paper also includes a more detailed examination of ways in which this innovative energy storage solution can be economically used in electric supply systems. The flywheel’s deep discharge and resilient, high-power cyclic capability, combined with a long design life, make it an ideal solution for voltage and frequency stabilization as well as an attractive, passive alternative for spinning reserves. The paper focuses and expands upon the strengths and limitations of today’s flywheel technologies. Finally, the effects and impact of the ways that energy is produced, delivered, and consumed are summarized.

Air-cooled generators have been fulfilling a wide range of applications recently. Concurrent with a low cost target, the market demands high efficiency and high performance designs. Windage and friction losses, caused by rotor rotation and cooling gas flowing through the ventilation circuits, represents one of the largest loss components in air-cooled generators. Carefully managing the windage and friction loss is critical to ensure the success of air-cooled generators. This work is motivated by development of air-cooled high-speed generators. In such applications, the flow inside the annular gap between the rotor and stator is highly turbulent. The flow characteristics are not fully understood. Physics-based correlations, which calculate the windage and friction losses, don’t exist in the literature. The purpose of this work is to develop such transfer functions for machine design. Numerical simulations, using commercial CFD code FLUENT 6.0 and Design of Experiment (DOE) method, have been carried out to study the flow characteristics in the annular space between the cylindrical rotor and stator. All simulations were performed using an axial-symmetric model, along with RNG k-ε turbulence model and enhanced wall treatment. In the study, the generator rated speed ranged from 5000 to 20000 rpm; the Taylor number ranged from 1750 to 78000; and the Mach number ranged from 0.25 to 1.0. The effect of axial flow on windage loss was carefully studied. Axial flow exhibited a strong impact on windage loss. The CFD results are rationalized. Transfer functions for windage and axial friction losses are created. They provide a better basis to explore the design space at the early stage of the product development.