Showing papers on "Base load power plant published in 1995"

Generator power system and method

Abstract: An integrated power system includes an engine/generator power supply integrated with storage batteries to provide household-like AC power. For a small load demand, the storage batteries are used to provide electricity. For a large load demand, the engine/generator starts to supply electricity. The engine/generator also recharges the storage batteries if the load demand is smaller than the engine/generator maximum load capacity. For a larger load demand, both the engine/generator and the storage batteries supply electricity in parallel. The engine speed is variable for various loads. The bigger the load, the higher the engine speed is required to produce the necessary power and keep a constant high DC voltage.

High-Capacity Factor Wind Energy Systems

Abstract: Wind-generated electricity can be fundamentally transformed from an intermittent resource to a baseload power supply. For the case of long distance transmission of wind electricity, this change can be achieved at a negligible increase or even a decrease in the per unit cost of electricity. The economic and technical feasibility of this process can be illustrated by studying the example of a wind farm located in central Kansas and a 2000 km, 2000 megawatt transmission line to southern California. Such a system can have a capacity factor of 60 percent, with no economic penalty and without storage. With compressed air energy storage (CAES) (and with a negligible economic penalty), capacity factors of 70-95 percent can be achieved. This strategy has important implications for the development of wind energy throughout the world since good wind resources are usually located far from major demand centers.

Power system using battery-charged capacitors

Abstract: A self-contained power system for powering a variable load uses a capacitor bank to power the load during periods of high current demand by the load at a steady load voltage. The capacitor bank is recharged during periods of lesser demand from a battery pack which has a lesser current output capability than the maximum load demand. The battery pack in turn is periodically recharged from an only intermittently available power source.

Compressor drive system for a natural gas liquefaction plant having an electric motor generator to feed excess power to the main power source

Abstract: In a compressor drive system for a natural gas liquefaction plant including a plurality of gas turbines each provided in an individual refrigeration cycle for pressurizing a different refrigerant, an electric motor is provided for each of the gas turbines so as to serve both as an auxiliary electric motor for generating a startup torque and as an AC generator, and the excess output power of the gas turbine is converted into electric power by this electric motor when the power requirement of the associated compressor is less than the power output of the gas turbine. Additionally, at least two of the gas turbines are of an identical make which is suitable for driving the compressor of one of the associated refrigeration cycles requiring a larger driving power. Therefore, the gas turbines can be operated at optimum conditions at all times without regard to seasonal changes of the operating conditions, and the efficient operation of the gas turbines will result in a significant reduction in the operation costs through a substantial saving of fuel consumption. Moreover, any excess power output of one of the gas turbines can be allocated so as to reduce the burden of the in-plant power station and/or to supplement the shortage of the power output of the other gas turbine, and the management of the stand-by units and spare parts can be simplified. These factors have a compounded effect in reducing the investment costs of the plant.

Power quality of wind turbines and their interaction with the grid

Abstract: The interaction of wind turbines (WT) with the grid has an evident influence on the voltage of the grid. The loss of power quality is depending directly on the intensity of the interference related to the capacity of the grid. In near future a certificate for power quality will be claimed by German utilities. This certificate will demonstrate the quality of power generation of a WT with respects to harmonics, power peaks, power factor and flicker for normal operation as well as for extreme and switching operation conditions. In this paper we present examples of the measurements according to the guideline. We show the grid interactions occurring during the operation of different WTs and how they possibly could be diminished. In addition the interaction effects of single WTs and wind farms will be compared.

Use of a static frequency converter for rapid load response in pumped-storage plants

Abstract: Most pumped-storage power plants have the capability to operate as synchronous condensers. As such, they can be brought online very quickly to support power system load requirements. However, one of the effects of making a rapid transition from synchronous condenser operation to turbine/governor operation is an initial reverse power flow into the machine. This reverse power flow can be very undesirable at a time when the power system is calling for load support. On weak or isolated power systems, this reverse power flow can lead to objectionable voltage and frequency dips in the power system. With the proper utilization of a static frequency converter (SFC) and its associated controls and auxiliary switchgear systems, the reverse power flow resulting from a transition from synchronous condenser operation can be eliminated. This paper describe a method by which an SFC system can be used to make this rapid load response in pumped-storage power plants without incurring a reverse power flow and to provide additional instantaneous short term power to support the grid.

Method and apparatus for adaptive and corrective determination of battery run-time in uninterruptible power systems

Abstract: The run-time available from an uninterruptible power system is accurately determined both during supply of power from the battery to the load and during the time where power is supplied directly from an AC power system to the load. During power outages, where power is supplied from the battery through the inverter to the load, the remaining run-time is first estimated by calculation and then corrected by modification of the calculated value according to the reciprocal of the run-time slope. Alternatively, a scaling factor is used as part of the first run-time calculations and a correction factor which applies more corrective weight as the time on inverter progresses may be used. During power outages and when power is supplied from the AC power system to the load the maximum available run-time is extrapolated from a table of values representing maximum available run-times at various levels of power being supplied to the load from a fully charged battery. These values are updated after inverter runs to reflect actual system run-times. The maximum run-times are thereby adapted to reflect battery aging and other unique characteristics of the system.

Electricity demand in Asia and the effects on energy supply and the investment environment

Abstract: Demand for energy (including electricity) has been increasing more rapidly in developing Asian economies than anywhere else in the world and is expected to continue growing. To meet rising demand, these countries must address such issues as how to meet the resulting enormous capital requirements and how to prevent environmental deterioration. To calculate what those capital requirements may be, and to estimate potential environmental damage, the authors built econometric energy demand models for seven economies: China, Indonesia, Malaysia, the Philippines, Republic of Korea, Taiwan (China), and Thailand. They estimate that electricity demand will increase an average 8.1 percent a year between 1993 and 2010. To finance power development projects, many governments are encouraging"build, operate, and own"or"build, operate, transfer"schemes, but there is a limit to the use of these schemes, which require foreign capital and thus reimbursements in hard currency. Because the seven governments must mobilize substantial domestic resources to finance capital requirements, it is essential that these countries develop or strengthen development of domestic bond and stock markets. To control emissions of pollutants will cost an estimated US$165 billion in 1994-2010.

Greenhouse gas emission reduction: A case study of Sri Lanka

Abstract: In this paper we describe a case study for Sri Lanka that explores a wide range of options for reducing greenhouse gas (GHG) emissions. Options range from renewable technologies to carbon taxes and transportation sector initiatives. We find that setting electricity prices to reflect long-run marginal cost has a significant beneficial impact on the environment, and the expected benefits predicted on theoretical grounds are confirmed by the empirical results. Pricing reform also has a much broader impact than physical approaches to demand side management, although several options such as compact fluorescent lighting appear to have great potential. Options to reduce GHG emissions are limited as Sri Lanka lacks natural gas, and nuclear power is not practical until the system reaches a much larger size. Building the few remaining large hydro facilities would significantly reduce GHG emissions, but these would require costly resettlement programs. Given the inevitability for fossil-fuel base load generation, both clean coal technologies such as pressurized fluidized bed combustion, as well as steam-cycle residual oil fueled plants merit consideration as alternatives to the conventional pulverized coal-fired plants currently being considered. Transportation sector measures necessary to ameliorate local urban air pollution problems, such as vehicle inspection and maintenance programs,more » also bring about significant reductions of GHG emissions. 51 refs., 10 figs., 3 tabs.« less

Frequency control capability of ABB combined-cycle gas turbine power plants

Abstract: Power stations used to support grid frequency must be able to operate in the part-load range so that they can supply the required power reserves. They must also be able to respond quickly within a few seconds after a collapse in grid frequency. Due to the quick reaction time needed, only gas turbines are used for this purpose. Gas turbines have a lower thermal efficiency in their lower part-load range but, if their control systems are properly designed, modern ABB gas turbines-as shown here using the GT 13E2 as an example-can, in conjunction with combined cycle power plants, meet all the requirements for frequency support capability specified in the Grid Code. A careful selection of the part-load point ensures that the gas turbine will operate at an optimum efficiency without being unduly stressed. (8 pages)

Combined cycle leads efficiency race

Abstract: Evidence of combined cycles` commercial success is everywhere and not just for peaking and small cogeneration purposes either. At 1,370 MW, Midland Cogeneration Venture has since 1990 operated one of the largest base-loaded independent power producer-owned plants in the United States. Using ABB power generation technology, the plant has set an hourly production record of 1,491 MWhr and a daily record of 34,842 MW and provides up to 1.35 million pounds per hour of process steam to nearby industrial users. More recently, Sithe/Independence Power Partners L.P. started commercial operation of its 1,020-MW (net ISO) combined-cycle cogeneration plant near Oswego, N.Y. The plant`s layout includes two GE multi-shaft combined-cycle systems that incorporate four 159-MW 7FA gas turbines, four Vogt heat recovery steam generators and two 209-MW GE steam turbines. Although the plant is primarily a baseload facility, it has been designed to handle up to 100 cold starts per year. According to GE, each combined-cycle block can reach full load conditions within five hours. Operational flexibility is further promoted via steam turbine bypasses that allow for simple-cycle operation without interrupting process steam to its industrial host. The topics of this article include: siting and permitting; steady efficiency gains; advanced turbine systemsmore » effort; and coal and the combined cycle.« less

Momotombo Geothermal Field

Abstract: With the beginning of operations of a 35-MW unit in Momotombo in August, 1983, Nicaragua joined the select group of countries that exploits geothermal resources for the purpose of producing electricity. Considering the old age of existing steam power plants, Nicaragua’s dependence on electricity, and its economic hardships, geothermal energy has become a vitally important source of base load power and the government is rapidly accelerating geothermal development.

When reliable power is not good enough

Abstract: The electric utility industry has done a good job of minimizing the long term outage, but for some industries, reliable power is not good enough. There is an increasing demand for premium quality power. The proliferation of sensitive electronic equipment at industrial and commercial sites has resulted in an increasing number of major power users who are sensitive to temporary voltage disturbances and momentary outages. An EPRI survey of distribution power quality reveals that the average site experiences several voltage sags per month. Many sensitive critical processes are impacted by these temporary events resulting in significant production losses and demands for better quality power that is free of voltage sags and momentary interruptions. Electric utilities are reallocating resources to better serve power quality sensitive customers. New technologies are emerging adding to the tools available. A commercial framework for power quality is needed to support the implementation of these technical solutions within today`s business environment. This paper discusses the concept of premium quality power, a new technical solution using superconducting magnetic energy storage to provide carryover support during temporary power disturbances, and two organizations who are addressing power quality head-on.

A study on automatic control of steam turbines of fossil power plant with thermal stress constraints in turbine rotors

Abstract: A new fuzzy turbine load scheduler is suggested for fast start-up/shut-down and load variation of fossil power plants. The turbine load scheduler determines the load increase/decrease rate by predicting steam conditions and calculating thermal stresses in the turbine rotors. Our load scheduler determines the load variation rate using fuzzy rules based on expert's knowledge concerning thermal stresses in the turbine rotors. A supervisory inference engine is added to update the expert's rules and to cope with time variations of the plant. The performance of the proposed scheduler is revealed via simulator for the Seoul Fossil Power Plant IV.

A new generation of nuclear reactors

Abstract: With modular construction, more-sophisticated communications, and safer designs, advanced light-water reactors are set to replace aging nuclear power plants. Seventeen years after the last nuclear power plant was ordered in the United States, nuclear engineers have designed, and in one case, begun constructing a new generation of advanced light-water reactors. These new reactors, which are simpler and safer, will replace aging reactor systems reaching the end of their licensed operation and provide extra baseload capacity for an expanding worldwide demand for energy. The new reactor plants have a modular design consisting of prefabricated components that can be shipped directly to a construction site for quick assembly. The designs are also simplified to enhance safety and reduce capital costs. The plants rely on modern digital control systems, sensors, and state-of-the-art computers to streamline and reduce the size of their control rooms. They use fiber-optics technology to transmit signals, cutting costs and construction time. Improved safety systems are a hallmark of the new reactors. In the midsize reactors (600 megawatts), natural forces such as gravity or convection are used as passive safety measures, which reduce the number of pumps, valves, and instruments required.

Implications for restructuring the electric power industry

Abstract: This report discusses the potential impacts of distributed power generation on the future of electric utilities. Developing power technologies such as cogeneration, advanced fuel cells, and gas turbines are also reviewed.