Power System Diagnostics

Project title:	Power System Diagnostics
Project researchers:	Phil Atwater, Jim DeHaan, Malin Jacobs, Lori Rux
Project ID:	FI.1
Duration of project:	FY96-FY98

Research problem being addressed and background
Project Objectives
Overall outcomes or conclusions
Partners who participated in the project
Publications and/or other deliverables which have been provided during this fiscal year

Research Problem and Background:
The Power System Diagnostics Research Project is formulated from the demonstrated problem areas in Reclamation electrical facilities and by the research-oriented requests of project personnel. The program focuses on improving the reliability, efficiency, and safety of Reclamation facilities and the associated interconnected electric power system. The project tasks are multi-faceted and evolved to solve repetitive problems or needs that are common Reclamation-wide.

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Project Objectives:
The project objectives are to (1) investigate and develop improved methods for testing and assessing the condition of high-voltage insulation of large motors and generators, (2) develop test methods and equipment to field test a prototype pulsed-current test set for safety grounding cables, (3) advance the design of the in-house fabricated fiber-optic air-core current transformer (CT) field testing instrument for commercialization, (4) secure modern, bug-free electromagnetic transients program (EMTP) software for world-wide power systems design, analysis, and diagnostics, and (5) test and evaluate acoustic monitoring techniques and analysis of electrical partial discharge activity in Reclamation power transformers.

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Overall Outcome or Conclusions:
Commercial partial discharge analysis (PDA) test equipment was installed on two large generators. Electromagnetic Interference (EMI) stator winding insulation signature tests were conducted on generators at Grand Coulee. EMI testing holds promise as another diagnostic tool to assess the overall condition of windings, but needs further investigation. An electrical test curve Asnaking@ characteristic observed in some Reclamation stator winding insulation test results was analyzed and correlated with physical deterioration. A project initiation document was prepared to purchase, install, and evaluate a rotor-mounted machine condition scanner at Grand Coulee.

Generator air housing ozone concentration measurements were quantified and analyzed.

Evaluation of CRADA sponsored commercial prototype ramped high-voltage insulation test set was terminated due to withdrawal of a vendor; new CRADA is underway.

Field test comparisons of methods to evaluate integrity of large machine stator cores were conducted.

A new method to electrically locate faults in large stator winding insulation was field tested using a laboratory version of rudimentary equipment.

An air-core CT instrument advanced from a temporary battery-powered to a remote laser-powered system.

The concept of testing safety ground cables with high-current (3,000 ampere) pulses was demonstrated in the laboratory with precursor equipment to a prototype test set.

Reclamation supported the Electromagnetic Transients Program Development Coordination Group at a level of about $14,000 per year (research funds from PS002). Version 3 software, with Windows installation options, is ready to be released.

No progress has been made on the power transformer acoustic monitoring project - postponed due to lower priority.

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Partners:
Grand Coulee, Davis, Flatiron, and Glen Canyon powerplants; Bonneville Power Administration; Photonics Power System, Inc.; AVO International; Electromagnetic Transients Program Development Coordination Group.

This photograph shows stator core tests being conducted after the catastrophic failure of a 10-MVA pump/generator stator winding. Extreme overheating and burning of the electrical insulation produced toxic chemical byproducts. Research was conducted to develop guidelines for proper working protection, site management and cleanup, and disposal of cleanup waste and failed machine components.

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Publications and/or Other Deliverables
A mitigation procedure was developed to reduce destructive concentrations of ozone in generators. The necessary filtering was installed at Davis Powerplant unit 2.

A new CRADA partner will be chosen to develop a commercial prototype ramp test set for Reclamation evaluation.

A working prototype ground cable test set will be developed, ready for commercialization, after a re-evaluation of the basic test method. A related technical paper is in progress describing field test results of the human shock hazard and the use of personal protective grounds in power facilities.

EMTP: The Consortium semiannual Development Coordination Group meeting had to be postponed to early November. Therefore, details of progress to date are not available. However, the Phase 2 reengineering of the code is underway.

Obtained benchmark PDA data/evaluation of winding insulation.

Milano, Bert, and Lorelynn M. Rux. 1998. Hazards Associated with the Cleanup of Failed Rotating Machinery Stator Insulation. Presented at the March 1998 Doble Client Conference, Boston, Massachusetts.

Technology transfer maturation funds are now being used to commercialize the air-core CT system.

The crude stator winding fault detector was very successful; commercialization will be pursued.

The insulation test curve snaking phenomena supported an assessment of advanced and widespread deterioration of generator winding insulation at Glen Canyon, requiring a rewind. The low power commercial stator core test method, known as EL-CID, was determined to be less favorable than the classic high power loop test.

Rodriguez, Rod, and Lori Rux. April 1997. Ozone Abatement in Air-Cooled Hydroelectric Generators. Bureau of Reclamation Engineering Monograph No. 44.

Rux, L.M. 1997. High-Voltage DC Tests for Evaluating Stator Winding Insulation: Uniform Step, Graded Step, and Ramped Test Methods. Presented at the October 1997 Conference on Electrical Insulation and Dielectric Phenomenon, Minneapolis, Minnesota.

Rux, Lorelynn M., and Richard L. Becker. 1998. The Ramped High-Voltage DC Method of Evaluating Stator Winding Insulation. Presented at the March 1998 Iris Rotating Machine Technical Conference, Dallas, Texas.

Rux, Lori. 1998. Glen Canyon Unit 8 Stator Winding Insulation Failure. Presented at the May 1998 Power Operations and Maintenance Workshop, Denver, Colorado.