Analysis method for liquid-filled electric equipment

• US 6,691,557 B1
• Filed: 10/10/2001
• Issued: 02/17/2004
• Est. Priority Date: 03/17/2000
• Status: Expired due to Term

• Current Assignee: 4R Enterprises Incorporated
• Original Assignee: Norman Rice
• Inventors: Rice, Norman
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): CYGAN, MICHAEL T
• Application Number:
  US09/974,355
• Time in Patent Office: 860 Days
• Field of Search: 73/530.1, 73/530.7, 73/614.2, 73/617.1, 73/617.2, 324/71.4, 324/204
• US Class Current: 73/53.07
• CPC Class Codes: G01N 15/04 Investigating sedimentation of particle suspensions
• CPC Class Codes: G01N 33/2858 metal particles

Abstract

The present invention is directed to a method for analyzing the maintenance status of liquid-filled electric equipment. An accurate indication of the maintenance state of an electric device and its insulating liquid is obtained using an analysis method comprising a particle analysis of suspended particles and sediment contained in the liquid. The analysis method can further comprise a chemical analysis of the insulating liquid. This analysis results in profiles of the liquid that give an accurate indication of the maintenance state of the electric device.

Claims

1. A method of evaluating the operation of electrical equipment using a liquid, comprising the steps of:

obtaining a sample of the liquid from the electrical equipment;

analyzing the liquid for particulate components, including the presence of electrical erosion products, to determine a profile of particulates in the liquid, the profile comprising predetermined particulate characteristics; and

determining an indication of the operating condition of the electrical equipment by analyzing the particulate profile.

2. The method according to claim 1, wherein the step of analyzing the liquid for the presence of electrical erosion products includes analyzing for the presence of techtites.

3. The method according to claim 1, wherein the step of analyzing the liquid for particulate components further includes analyzing for filming, fibers, coking, techtites, Fe rubbing, oxides and tempered metallic particles.

4. The method according to claim 1, further comprising:

analyzing the liquid for non-particulate components, including the presence of non-volatile insulating liquid degradation products, to determine a profile of non-particulate components, the profile comprising predetermined non-particulate characteristics.

5. The method according to claim 4, wherein the step of analyzing the liquid for the presence of non-volatile insulating liquid degradation products includes analyzing for the presence of hydrocarbons.

6. The method according to claim 4, wherein the step of analyzing the liquid for non-particulate components includes analyzing for hydrocarbons, water, hydroxyls, oxides, sulfates, coking and viscosity.

7. The method according to claim 4, wherein the steps of analyzing the liquid for particulate components and analyzing the liquid for non-particulate components include determining particle count, particle count distribution, particle count concentration, particle count composition, particle count shape, compound evaluation for coking, oxidation, nitration, sulfate, alkanes and moisture, particle type composition, particle size, and particle shape.

8. The method according to claim 4, wherein the step of analyzing the liquid for non-particulate components comprises at least one chemical analysis method selected from the group consisting of infrared spectroscopy, mass spectroscopy, gas chromatography, liquid chromatography, wet chemical analysis, atomic emission spectroscopy, and inductively coupled plasma spectroscopy.

9. The method according to claim 1, wherein the step of analyzing the liquid for particulate components comprises at least one particle analysis method selected from the group consisting of optical microscopy, laser extinction, ferrography, particle counting, and metal heat treatment.

10. The method according to claim 1, wherein the predetermined particulate characteristics profile include at least one member selected from the group consisting of techtites, rubbing particles, sliding particles, cutting particles, rolling contact particles, ferrous oxides, carbonaceous particles, filming particles, paper, fiber, cellulosics, dirt, sand, and tempered metals.

11. The method according to claim 1, wherein the step of determining an indication of the operating condition of the electrical equipment comprises:

comparing the particulate profile to a standardized particulate profile.

12. The method according to claim 1, wherein the electrical equipment is an electric power transfer device.

13. The method according to claim 1, wherein the electrical equipment is selected from the group consisting of transformers, load tap changers, tap changers, circuit breakers, off-load tap changers, on-load tap changers, switches, x-ray machines, and electric discharge machines.