Westinghouse Electric Corporation

Electric Power Research Institute Incorporated

Robert L Osborne

Michael Twerdochlib

James C Bellows

Christian T Kemper

Paul H Haley

Paul F Rozelle

James W Wonn

Eddie Y Hwang

Wu-Shi Shung

Thomas Andrew Lemak

Stephen J Jennings

Avelino J Gonzalez

Karl E Harper

The present invention monitors RF emissions within a turbine generator. A coupling device provides a connection between preexisting thermal sensor leads and an RF monitor. Preexisting thermal sensor leads are connected to thermocouples and resistance temperature detectors during manufacture of the turbine generator. The RF monitor is used in the present invention to monitor RF emissions flowing in the thermal sensor leads thereby avoiding a need to retrofit RF sensors on the generator. The present invention also provides a capacitive coupling means between the thermal sensor leads and the RF monitor. The present invention also provides an inductive means to reduce interference from RF emissions having sources external to the generator.

Apparatus and method for identification and location of internal arcing

The present invention is an expert system test system which has the capability of exercising all combinations of data input types using specialized data test sets. The specialized data test sets include a set of sensor values for each level of an operating system. All levels of diagnosis can be tested without testing every possible sensor value and combination of sensor values. The test sets can be combined to produce various orders of testing allowing complex relationships between sensors and rules to be tested. The system includes a test plan which is used by the testing system to iteratively apply the normal and specialized test data to the expert system. Changing the sensor values produces outputs for each iteration which are compared to expected results or to a baseline. Each test produces a log file which can be examined by the knowledge engineer. If exceptions are produced, the system produces an exception report which allows the knowledge engineer to determine whether the exception is abnormal or unexpected. An output log is also stored as historical data and used with future tests to obtain a complete test regression comparison using conventional database comparison tools. The system includes a test language which allows the user to formulate a test plan without the need for complicated programming associated therewith by designating the rulebase to be used, and by defining the order of the test and the tests performed therein, along with exceptions which include exceptions which include simple, set and sufficiency type exceptions.

Expert system tester

The system of the present invention uses the importance of a piece of malfunctioning equipment, the severity and the confidence level in a diagnosis to determine repair priority of the equipment by obtaining the product (46) of the confidence level (CF), importance (IMP) and severity (SEV). The these variables are determined by expert system rules. The severity is the reciprocal (88) of the time to failure. The importance (44) is the cost to repair the maximum damage when the malfunction continues. A malfunction can affect several pieces of equipment in combination, the severity and importance associated with each piece is combined (70) with the confidence and used to determine the repair priority. When the diagnosis of a malfunction is by malfunctioning sensors, the expected equipment life (40) and the availability (86) of sensors that provide a partial backup are considered in prioritizing sensor as well as equipment repair. When a primary piece of equipment is backed up (100), the effect of both pieces of equipment failing (106) is considered in prioritizing the repair. The system ranks the repair of all possible malfunctions on a common scale. The system gives a complete repair priority picture and allows the cost effectiveness to be maximized.

Automated system to prioritize repair of plant equipment

A method of determining the untwist of turbine blades under dynamic conditions is comprised of the steps of producing a first pair of blade passing event signals in response to a blade tip's movement past a pair of fixed sensors. The signals comprising the first signal pair are compared to one another to establish a first differential value. Another data point containing blade vibrational information is produced. The first differential value and the other data point are evaluated to discriminate between blade untwist and synchronous vibration. Based on the magnitude of the blade untwist, inferences can be drawn regarding the status of the turbine blade lashing wires.

Method for determining the untwist of turbine blades

A shrouded turbine blade vibration monitoring system is comprised of a plurality of sensors for sensing a profile of a turbine blade row. A microprocessor compares the sensed profile to an expected profile of the turbine blade row to detect motion of the turbine blades due to vibration. The microprocessor then generates an operator alarm and trips the turbine in response to the detection of unacceptable vibration of the turbine blades.

Shrouded turbine blade vibration monitor

A turbine blade shroud clearance monitoring system is comprised of a plurality of sensors for measuring the clearance between the stationary portion of the turbine and the shroud segments in each turbine blade row. The measurements are averaged by a microprocessor to produce an average clearance value for each shroud segment. The microprocessor then analyzes the average clearance values for each shroud segment to determine when the clearance between a shroud segment and the stationary portion of the turbine is approaching a critical value. Output responsive to the foregoing analysis is then generated.

Apparatus and method for monitoring steam turbine shroud clearance

In an active shaft ground system for maintaining a rotating shaft (4) of a machine substantially at ground potential, which system includes a circuit coupled to the shaft (4) for monitoring the voltage on the shaft (4) relative to ground and a brush (6) coupled to the circuit and contacting the shaft (4) for conducting to the shaft (4) a compensating current having an amplitude and polarity adjusted for maintaining the shaft voltage substantially at ground potential, there is provided shaft condition detection circuitry (18,20,24,26,28,34,36) coupled to the circuit for monitoring the voltage on the shaft (4) relative to ground and the current flowing between the brush (6) and the shaft (4) and for producing a fault indication when the voltage on the shaft (4) relative to ground is outside of a selected range at the same time that the current flowing through the brush (6) is substantially equal to zero. The detection circuitry permits reliable monitoring of brush bounce and distinguishes between that condition and brush rub.

Brush bounce detection in active shaft ground system

A steam turbine control system which includes a manual panel with pushbuttons for operator control of the steam admission valves. Each valve has its own control means and is responsive to pushbutton activation to govern its valve movement. If a pushbutton indicating valve opening or closing gets stuck, the operator pushes a pushbutton indicating opposite movement and the control means switches to a special control mode after a predetermined period of time. In the special mode valve movement stops after removal of the operator's finger pressure and valve movement is accomplished by activation of predetermined pairs of pushbuttons.

Stuck pushbutton contingency operation for a steam turbine control system

A diagnostic system wherein a central diagnostic center receives sensor data relative to the operating condition of a plurality of remote plants. Each plant records just certain sensor signals and transmits them at respective prescheduled transmisssion times. If certain activation limits are exceeded, a data link with the diagnostic center is immediately established so that the data may be transmitted ahead of its normally scheduled transmission time in order that an immediate diagnostic analysis be made on the plant. A communication link between the plant and diagnostic center is kept open for a predetermined period of time in which more data may be sent from the plant to the diagnostic center, and results and instructions, sent from the diagnostic center back to the plant. Such instructions may include the changing of certain parameters in the examination of the sensor signals.

Diagnostic system and method

A rub between the rotating and stationary parts of a turbine is detected by connecting the rotor to electrical ground and introducing electrical energy into the rotor-ground circuit. A rub between the rotating stationary part modifies the currents in the grounding circuit to an extent that the condition may be detected so as to provide a rub indication. In another embodiment the rotor discharge current in one or more grounding devices normally associated with a turbine is monitored to detect any abnormal condition.

System for monitoring metal-to-metal contact in rotating machinery

Diagnostic apparatus for monitoring a system subject to malfunctions. Estimates are obtained relating normal system operation to operating variables. Estimates are additionally obtained relating specific malfunctions to specific variables. The variables are combined in accordance with predetermined functions to get an indication of a particular malfunction. This indication is modified by a factor related to the normal operation of the system to yield a probability of the occurrence of the malfunction, and which probability is limited to a value less than 100%.

Method and apparatus for the automatic diagnosis of system malfunctions

Fouling which occurs in the heat exchangers of a thermal energy conversion power plant causes the heat transfer between the circulating fluid and working fluid to be degraded, diminishing the efficiency of the plant. The invention provides for optimizing the net power level of the plant by perturbing the flow of circulating fluid individually to the heat exchangers to identify the direction of flow change which results in an increase in generated net power level and adjusting the flow of circulating fluid to each heat exchanger. This optimization may be carried out periodically. In another case, when temperature differential of the circulating fluid across at least one of the heat exchangers falls below a predetermined level, only the circulating fluid of the related heat exchangers need be altered to optimize the net power level generated by the plant. Heat exchanger fouling may cause the plant to be shut down for cleaning of the heat exchangers during a cleaning time interval succeeding each operational time interval. Another aspect of the invention provides for deriving a ratio of operating time interval to corresponding cleaning time interval which maximizes the net electrical energy produced by the plant.

Power plant optimization control

Present speed and present steam temperature are utilized in accordance with a mathematical model to evaluate present steam to turbine heat transfer and turbine heat propagation quantities, and present turbine rotor and casing surface and volume average temperatures. The model is corrected for inaccuracy based on comparison of calculated rotor to casing differential expansion with measured values, and is exercised once more with anticipated speed and steam temperature quantities to develop anticipated rotor to casing differential expansion and anticipated rotor stress. These quantities are compared with various predetermined limits to determine whether the present and anticipated speed and acceleration are within allowable limits.

Anticipative turbine control

A method and apparatus for testing the movability of a valve plug. The invention provides for movement of the valve plug from a first to a second position, from the second to a third position in an opposite direction, and again in the first direction to the first position. Indicators are provided to ascertain if such movements have occurred. Alarm signals are generated if any of the movements do not occur. The magnitude of the motions of the plug is normally small relative to the full valve stroke. Size of stroke and time at each position are chosen to minimize any disturbance to the power system.

Growing community of inventors

Winter Springs, FL, United States of America

Robert L Osborne