Showing papers on "Stand-alone power system published in 1981"

Excitation System Models for Power System Stability Studies

Abstract: Excitation system models suitable for use in large scale system stability studies are presented in this paper. With these models, most of the excitation systems currently in widespread use on large, system connected generators in North America can be represented.

Wind power generator and control therefore

Abstract: A wind powered generator for generating electrical energy comprising a generator which has no slip rings between its field and armature, and which when mounted on a tower is controlled through suitable control mechanism to adjust the power output to a level compatible with the load and storage equipment, as well as the existing wind conditions. The armature is fixedly mounted on the support (which can turn about an upright axis) and a housing carrying permanent magnets rotates around the armature. Bearing means stably support the housing and the armature and the propeller is easily mounted on the housing. The device is made to be relatively maintenance free and capable of unattended generation of electricity over extended periods of time.

Power/energy: Demand-side load management: The rising cost of peak-demand power means that utilities must encourage customers to manage power usage

Abstract: As electricity cost increases, more and more utilities are extending their activities into once-forbidden territory: the customer's side of the meter. In order to increase efficiency and hold the line on costs, they are controlling, directly and indirectly, when and how the electric energy is used-shifting from a supply-side-only viewpoint to demand-side technologies. They are including the customer as a new utility corporate planning option. This control is called load management. It aims to even out or change the magnitude of hour-to-hour and season-to-season variations in electricity demands; it cuts off the peaks and fills in the valleys in demand-time curves. The procedure benefits utilities by allowing more uniform use of generating equipment and thus benefits users by helping to hold down rates. Implementation and effects of this type of load management are discussed.

SOLSTOR Description and User's Guide

Abstract: The computer simulation code SOLSTOR is described. The code simulates energy systems in which electricity is generated by either a photovoltaic (PV) system or a wind turbine generator (WTG). Storage may or may not be present. Backup electricity, if needed, is provided either from a utility grid or from a fuel-burning generator. SOLSTOR minimizes the life cycle cost of providing energy by choosing the optimal solar or wind system component sizes. Rates for electricity purchased from the grid can include time-of-day (TOD) energy charges as well as time-of-day peak demand changes. Sell-back to the grid of excess collected energy is also considered.

Projected Costs for Electricity and Products from OTEC Facilities and Plantships

Abstract: The vast ocean thermal resource of the tropics can be used to serve all areas of the U.S. through the production at sea of fuels or energy-intensive products that can be transported to market by ship. This paper addresses ammonia, liquid hydrogen, methanol, and liquid methane, which could be sold as fuels or chemicals or used as hydrogen sources for onshore fuel-cell power systems. Estimated costs of their production on 325-MWe ocean thermal energy conversion (OTEC) plantships and their delivery to U.S. ports and inland cites are presented. The most promising product is ammonia, first for use in fertilizers and the chemical industry, and later as the least costly carrier of hydrogen for use in fuel cells. Estimated costs of delivering OTEC electricity by undersea cables from moored offshore plants to U.S. islands and Gulf Coast states are compared with costs of electricity from OTEC ammonia and from coal and nuclear power. Commercial viability for both OTEC approaches by the 1990-1993 period is indicated. The potentials for private cost-sharing in the initial 40-MWe demonstration facilities and plantships also are discussed.

Power Conditioning Unit for Photovoltaic Power Systems

Abstract: This paper describes a Power Conditioning Unit (PCU) for solar photovoltaic energy collection system. The PCU rated 50/62,5 kVA, 50/60 Hz, 3-phase, 4-wire has the capability to operate in a stand-alone mode or paralleled with a commercial 3-phase utility power line. The quality of power is compatible with that of the electric utilities.

Lightweight storage battery

Abstract: A hybrid lightweight storage battery combining aspects of conventional storage batteries and fuel cells in a manner such that the structural weight of the battery is minimized, whereas the power output is maximized in relation to the potential of the battery components.

Simulation of the Dynamic Performance of a PWR Plant as a Power Supply in a Large Power System

Abstract: This work aims at modeling, simulating and analyzing the dynamic performance of the first egyptian pressurized water reactor nuclear power plant as a power supply in a forecasted national power system. A digital simulator has been developed which incorporates nonlinear mathematical models for: a PWR, pressurizer, steam generator, coolant pumps, steam and hydro-turbines, synchronous machines, loads and other network components, plant controllers and speed governors. The results obtained include: 1. The dynamic response of the nuclear plant following the forced outage of two of the feeding Transmission Lines (T.L's.), i.e. 21 % loss of the area power supply. 2. The overall system frequency behaviour following the disconnection of the PWR plant. 3. A comparison between Dynamic Energy Balance (DEB) frequency calculations of the overall power system (represented by its center of inertia) and the transient stability calculations of the nuclear plant system frequency following the loss of 28 % of the area power supply.

A preliminary estimate of future communications traffic for the electric power system

Abstract: Diverse new generator technologies using renewable energy, and to improve operational efficiency throughout the existing electric power systems are presented. A description of a model utility and the information transfer requirements imposed by incorporation of dispersed storage and generation technologies and implementation of more extensive energy management are estimated. An example of possible traffic for an assumed system, and an approach that can be applied to other systems, control configurations, or dispersed storage and generation penetrations is provided.

Photovoltaics in the Context of off-Grid Small Power Systems

Abstract: The subject area is defined as:-’ stand alone, off-grid continuous power systems up to 20 kW’. The paper focuses on the practical criteria which determine cost/effectiveness to the user in different applicational areas. Both utilisation and load factors can be important in determining overall power costs in many systems, and their product, — which may be expressed as the average power off take factor, — gives a useful first order approximation for comparative costings. of the many systems studied, only those based on internal combustion engined generating sets and photovoltaic (PV) systems are presented. Both ‘standby’ and ‘mobile short-life’ construction type applications are not considered amenable to PV penetration. However, isolated non-mobile high utilization systems and ‘village electricity’ are potential areas for PV competition. Despite their current very high first cost, medium to high offtake PV systems are already competitive in overall power costs with small gasoline driven sets. With progressively lower module and balance of system costs, continuous power PV systems should be able to compete with the larger gasoline sets by the middle of this decade. Diesel electric systems are more reliable and fuel efficient so that power cost parity for a 5 kW PV system may not be achieved until the second half of this decade or the first half of the next decade,-depending on fuel cost scenarios.

Modeling Electricity Production-Demand Correlations for STEC Plants in Dispersed Locations

Abstract: It has been a recent task of IIASA's Energy Systems Program to study solar energy and in particular opportunities for deploying large-scale solar technologies for electricity production in a set of countries. In this context the present simulation model was developed. This model called STECP was used to investigate the electrical output of solar plants with and without internal thermal storage that were conceived to be spread across three different time zones. As a result, it appears that a higher reliability of electricity supply can be achieved if the solar plants are sited in dispersed locations than if they were concentrated in one place. Introduction of internal thermal storage in the system of solar plants increases its seasonal electric output from two to three times and decreases external storage requirements. The model, which is described here along with some application results, permits a consistent investigation of the electricity production-demand correlation for a system of solar electric plants.