Optical waveguides – Optical waveguide sensor
Reexamination Certificate
2002-06-24
2004-04-13
Ullah, Akm Enayet (Department: 2874)
Optical waveguides
Optical waveguide sensor
C385S037000, C374S161000, C250S227140
Reexamination Certificate
active
06721470
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to an optical measurement device for an electrical appliance having at least one electrical conductor that is pressed into a slot, which has two slot side walls, in a base body. In particular, the invention relates to an optical measurement device for an electrical appliance that is used in the field of electrical power generation and distribution, such as an electrical generator or an electrical transformer.
Such an electrical appliance, which is also referred to as power equipment, represents a very expensive and long-term investment. Its failure not only endangers the power equipment itself but, possibly, also results in very severe service reductions due to the down time associated with repair. To avoid such a condition, increasing use is being made of a diagnosis system, which may, for example, also include an optical measurement device, for early identification of defects. The diagnosis system furthermore allows a higher utilization level, making the power equipment more financially viable.
The physical configuration of the power equipment is optimized with regard to high efficiency, low eddy current losses, compact construction and good electrical isolation. For this reason, there are also no unused intermediate spaces or empty spaces in which a sensor could be accommodated without any redesign effort, especially in the active part of the power equipment. A stator winding or else a rotor winding of an electrical generator contains, for example, a large number of conductor bars that are pressed at high pressure into slots in a base body, in particular, a laminated stator core or a rotor body. This results in the compact construction that has been mentioned, without any significant intermediate spaces.
During operation, the conductor bars carry a very high electric current that may assume values up to the kA range, so that they are heated to a considerable extent. Their precise temperature, therefore, represents one of the important diagnosis information items. Due to the high potential difference between the individual conductor bars and between the conductor bars and the base body, an electrical sensor is not suitable for such a measurement task.
For this reason, the overview article “Fiber Sensors for Industrial Applications” by M. Lequime, 12th International Conference on Optical Fiber Sensors, 28-31.10.1997, pp. 66-71, describes various optical measurement devices for an electrical generator, which each use at least one optical sensor for measurement value detection. This is because, in contrast to a conventional electrical measurement sensor, an optical sensor can still operate very well in the presence of a high electrical voltage (typically greater than several tens of kilovolts), a high magnetic field (up to 5 Tesla), and in a corrosive atmosphere (hydrogen or sulfur hexafluoride). In addition to detecting the temperature of the coolant that is used, inter alia, for cooling the conductor rods, the described optical measurement devices also detect the vibration spectrum. Not only a fiber-optic point sensor, which is configured for a single measurement point, but also a fiber-optic sensor network with a number of measurement points are used.
The specialist article “A Temperature Optical Fiber Sensor Network: From Laboratory Feasibility to Field Trial” by H. Fevrier et al., 8th Optical Fiber Sensors Conference, 29-31.01.1992, pp. 262-265, describes an optical measurement device that is in the form of a fiber-optic sensor network with effectively distributed temperature detection using a so-called Optical Time Delay Reflectometry (OTDR) technique. During a field test on a 250 MW generator, a number of optical temperature sensors were positioned within the generator housing—some on a nonmagnetic protective plate at ground potential and some on a coolant circuit water chamber at a high-voltage potential. However, no details are given about the precise installation precautions for the optical sensors or about the optical waveguide routing within the generator.
The specialist article “Industrial Prototype of a Fiber-Optic Sensor Network for the Thermal Monitoring of the Turbogenerator of a Nuclear Power Plant—Design, Qualification, and Settlement” by C. Meunier et al. in Journal of Lightwave Technology, Vol. 13, No. 7 July 1995, pp. 1354-1361, discloses a further optical measurement device for temperature detection in a 900 MW turbogenerator. The fiberoptic sensor network is, in this case, based on so-called white light interferometry, which makes it possible to interrogate a number of optical sensors at the same time. The optical sensors, which are intended for water temperature measurement, are adhesively bonded onto a water connecting element, which is located on a conductor in the outlet region of the coolant line. The application point for the optical sensors is, thus, disposed in the region of the end winding of the generator winding.
Furthermore, on the Internet page:
http://www.luxtron.com/product/utility/fiber.html (as of Dec. 13, 1999), the Luxtron Corp. describes an optical sensor that is based on temperature-dependent fluorescence of a sensitive element. The sensor is particularly suitable for temperature measurement on the conductor winding of a high-voltage power transformer. However, no disclosure is given of how the temperature sensor can be applied to the conductor winding, or how the optical waveguide for supply purposes can be routed within the power transformer.
Furthermore, European Patent Application EP 0 071 561 A2 discloses an operating system to be monitored by optical waveguides. In addition, International Patent Application WO 98/31987 A1, corresponding to U.S. Pat. No. 5,892,860 to Maron et al., discloses a measurement variable being detected by an optical sensor in the form of a Faser-Bragg grating sensor. The Faser-Bragg grating sensor is, in this case, fitted to an electrical pump within a (natural oil) bore hole, and is connected to an evaluation unit on the earth's surface.
The prior art optical measurement devices, thus, allow either only indirect measurement variable detection, for example, in the case of determining the temperature in the coolant circuit, or there are no specific details as to how the optical sensor and the supplying optical conductor for direct measurement variable detection can be disposed, for example, on the conductor to be monitored on the conductor winding to be monitored.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an optical measurement device for an electrical appliance having at least one electrical conductor that is pressed into a slot, which has two slot side walls, in a base body that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that detects the measurement variable as directly as possible on the electrical conductor. In the process, the operation of the electrical appliance should be influenced as little as possible. Furthermore, no redesign of the electrical appliance shall be required to make it possible to operate the optical measurement device.
With the foregoing and other objects in view, there is provided, in accordance with the invention, an optical measurement device for an electrical appliance having a base body with at least one slot having two slot side walls and at least one electrical conductor having a longitudinal face facing away from the two slot side walls and a plurality of conductor elements insulated from one another, the conductor pressed into the one slot, the optical measurement device including at least one optical sensor, at least one optical waveguide having a part adjacent the optical sensor and being connected to the optical sensor, the optical sensor to be interrogated by a light signal through the optical waveguide, an evaluation unit optically connected to the optical sensor, the optical sensor and the part to be disposed in a region of the slot at the longitudinal face, and at least one protective
Bosselmann Thomas
Krämmer Peter
Theune Nils Michael
Willsch Michael
Petkovsek Daniel
Siemens Aktiengesellschaft
Ullah Akm Enayet
LandOfFree
Optical measurement device in a pressed-in conductor bar in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical measurement device in a pressed-in conductor bar in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical measurement device in a pressed-in conductor bar in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3257090