Siemens Energy, Inc.

Siemens Westinghouse Power Corporation

Siemens Power Generation, Inc.

James Frederick Lau

Edward David Thompson

Douglas J Conley

Benjamin Todd Humphries

Franklin T Emery

Michael Twerdochlib

Robert John Nelson

Evangelos V Diatzikis

Abraham Nieves

Kim M McCreight

Constance M Smith

Anand Banthia

Gustavo Gamboa

Bobby A Warren

An apparatus and a method for testing a stator core of a generator are presented. The apparatus includes a power supply. The power supply provides an excitation current having a base frequency. A frequency convertor is connected to the power supply. The frequency convertor converts the base frequency of the excitation current to an excitation frequency that is greater than the base frequency. An excitation cable connects the frequency convertor to a rotor at two axial ends. The rotor is excited by the excitation current with the excitation frequency as a single excitation winding for simulating an operation state of the generator causing hot spots on the stator core without overheating the rotor.

Apparatus and method for testing stator core of generator

A device and method for detecting and analyzing faults in a generator stator are disclosed. The device and method include measuring a direct current component of a neutral ground current in a generator stator grounding conductor, analyzing the direct current flow and comparing it with other ground fault indicators, and providing diagnosis and recommended actions based on the analysis. The direct current flow is measured by a sensitive direct current sensor that may also measure AC components via oscillations in the current measurement, such as a Hall Effect sensor, placed on the generator stator grounding conductor. The analysis of the direct current signal includes consideration of the generator operating conditions and environmental conditions, and also includes comparison to historical data representing both normal and abnormal operation of the generator. Alarms and advisories are provided when generator faults are detected or predicted.

Generator neutral ground monitoring device utilizing direct current component measurement and analysis

Fault analysis and detection involving a generator neutral ground includes monitoring a voltage waveform across a neutral grounding transformer of a generator. During monitoring of the voltage waveform a sample of the voltage waveform is acquired. Previously, a number of similar past samples of the monitored waveform were acquired and stored as well. The present sample is compared to one or more of these stored, past samples so that, based on a similarity between the present sample to the past samples, a generator fault indicated by the present sample can be identified. Identifying the generator fault can include recognizing that it is presently occurring or that it may occur in a predictable timeframe. Additionally, identifying a component of the generator that caused, or will cause, the generator fault can be identified as well. A diagnostic message or control signal based on the identified generator fault can then be generated.

Generator neutral ground monitoring system and method

A system and method for monitoring the condition of a vibration sensor in a system. Vibrations are received in the system at one or more vibration sensors. Sensor data is output by the vibration sensor(s). The sensor data includes data representative of the vibrations in the system and data representative of a natural frequency of the corresponding vibration sensor. The sensor data output from the vibration sensor(s) is monitored, and upon a change in the data representative of the natural frequency of a vibration sensor, that vibration sensor is flagged.

Method for monitoring the condition of a vibration sensor

A method for measuring a tangential tightness of a stator coil within an armature slot of a stator assembly in an electric generator. The stator coil is excited to produce a vibratory response therein. The vibratory response of the stator coil is detected and a frequency response function of the vibratory response is determined. A tangential tightness of the stator coil within the armature slot is estimated based on the frequency response function of the vibratory response of the stator coil.

Method of in slot tightness measuring of stator coil

A conformable layer () for inhibiting electrical discharge between vent tubes () and strands () in an inner-cooled coil (). The conformable layer comprises a resistive inner core () and a conductive strip () wrapped in a conductive outer wrap (). The conductive strip () is electrically connected to the strands () at one end of the coil () and left to electrically float at the other end. In this configuration, the conformable layer () reduces voltage buildup between the vent tubes () and the strands () to help prevent electrical damage to the coil ().

Electrical-discharge-inhibiting conformable layer for use in inner-cooled coils

Electrical-discharge-inhibiting conformable layer for use in inner-cooler coils

The present invention provides for thin sheet wedges that comprise a mica matrix impregnated with a conductive resin. The mica matrix is composed of mica flakes. The thin sheet wedge has a semi-conductive property of 500&#x2013;500,000 ohms per square. In one embodiment the thin sheet wedge further comprises at least one glass fiber layer. In a particular embodiment the glass fiber layer is a backing for the mica matrix. In another particular embodiment the glass fiber is interwoven with the mica matrix. The glass fiber layer may itself be impregnated with a conductive resin.

Thin sheet mica wedges with semi-conducting properties

A blown fuse proximity sensing deviceis for use with a rectifying wheelof a type including rectifying diodesand associated fuses. Each fusemay include a housing, a fuse elementcarried by the housing, and a pop-out indicatormovable between a normal position and a popped-out position. In the popped-out position, the indicatorextends outwardly from the housing responsive to failure of the fuse element. At least one stationary proximity sensoris mounted adjacent the rectifying wheelfor sensing positions of the pop-out indicatorswithout contact therewith during rotation of the rectifying wheel to thereby sense at least one blown fuse. The sensing devicemay also include a local display, and a controllerconnected to the stationary proximity sensorfor generating an indication of a blown fuse on the local display. The controllermay also generate at least one remote output, such as to be monitored by other plant control equipment.

Sensing apparatus for blown fuse of rectifying wheel and associated methods

The present invention monitors an electrical generator ( ) to provide an indication of a problem in the generator's bearing insulation ( ), such as insulation damage or insulation bridging, and sets an alarm to warn an operator of the problem, thereby avoiding damage to the electrical generator ( ). Methods and systems consistent with the present invention identify problems with bearing insulation ( ) by monitoring the naturally occurring shaft voltage on the generator rotor ( ) and by setting an alarm if the shaft voltage drops below a predetermined value.

Method and system for on-line monitoring of bearing insulation in an electrical generator

A turbine power generator includes a housing a shaft a turbine to drive the shaft, a shaft-driven generator rotor and generator stator within the housing and surrounding the rotor. A main cooling gas blower includes at least one blade driven by the shaft for causing a main flow of cooling gas to cool the rotor and/or stator A supplemental cooling gas blower is connected in parallel with the main cooling gas blower for causing a supplemental flow of cooling gas through the housing in addition to the main flow of cooling gas to cool the rotor and/or stator The supplemental cooling gas blower may include an electric motor and at least one blade driven thereby. A controller may be connected to the electric motor to permit selective operation of the supplemental cooling gas blower

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Orlando, FL, United States of America

James Frederick Lau