Generator and exciter parameter estimation of Fort Patrick HenryHydro Unit 1

This paper describes the techniques employed for extraction of device parameters for a 20 MVA hydro-turbine generator in the Tennessee Valley Authority (TVA) power system. Several approaches were implemented in the extraction of parameters. Measurements on the generator were made prior, and subsequent, to extensive rework as part of a generator upgrade project. In addition, static exciter and overall response tests on the complete system were performed after the upgrade. The identified generator parameters before and after the upgrade are compared     

Optical voltage and current sensors used in a revenue meteringsystem

The authors discuss the development of an optical voltage sensor as part of an all optical sensor based revenue metering system. The magnetooptic or Faraday effect was used to implement a magnetooptic voltage transducer (MOVT) to measure voltage by sensing the current flow through a capacitor connected from a 161 kV transmission line to ground. The current sensor was a magnetooptic current transducer (MOCT) developed previously. The design of the voltage sensors using the magnetooptic effect allows the implementation of a revenue metering system using all optical sensors. This method of measuring voltage was previously unproven. The components of the all optical sensor revenue metering system, the site installation, and the data acquisition system used to monitor the system are described. Decisions leading to the design of the MOVT are discussed     

A magneto-optic current transducer

A current measurement technique using the magneto-optic or Faraday effect, has been developed, tested, and demonstrated. The device developed is a magneto-optic current transducer (MOCT). It uses the rotation of the plane of polarization by a magnetic field exhibited in certain glasses (Faraday effect). Test data obtained in an extensive field evaluation of the MOCT were compared with the design qualification data gathered during the development phase of this project. The analysis indicates that operation of the MOCT-based metering system under field conditions compares favorably with performance predicted during design qualification     

Emulsification of thermal energy storage materials in an immiscible fluid

The problems of thermal energy storage are of major importance in the development of intermittent energy sources and the efficient usage of conventional energy supplies. Utilization of latent heat materials for thermal energy storage has been plagued by the build-up of solids on cooling surfaces and the resulting low heat transfer rates. A novel system has been investigated in order to alleviate these difficulties. Small droplets of latent heat material were suspended in an immiscible heat transfer fluid to form an emulsion. The generation of stable emulsions is an empirical art, for which the selection of surface-active agents and the method of mixing play the key roles. A total of 42 latent heat storage emulsion samples were prepared using a diphenyl compound as the organic phase. Most of the samples were prepared using a high speed mixing apparatus. Several emulsified blends exhibited favourable prolonged storage and cycling behaviour. Estimates based on apparent viscosity measurements indicated that high rates of heat transfer could be obtained with this system. Assuming turbulent flow conditions and 60 per cent salt loading, a value for the mean film coefficient of heat transfer was calculated to be about 1045 J/m² s °C. The concept offers potentially large heat exchanger cost reductions, while retaining 60 per cent of the volume savings attainable in latent heat systems.