MW-class Turbine Research Articles

Fault detection method based on an automated operating envelope during transient states for the large turbomachinery

In the energy generation business steam powered turbo-generators still play an important role in electrical power generation all over the world. Every facility using steam turbines considers them as the critical machinery. Such machines should be well-maintained, properly handled, and precisely diagnosed in order to achieve the best performance and safety. The most valued data about the technical health are collected during machine’s shut-downs and run-ups. These data are more than seldom and hard to assess without expert’s knowledge with strong theoretical background and experience. Main novelty of the paper is the automated method for novelty detection of machine’s vibration. Most proposed methods apply to smaller machines with rolling bearings, whereas we propose the method for large machines with sliding bearings, which have much different behavior. The application of the method is support of the plant maintenance staff to evaluate deviations of turbo-sets from a healthy state based on the concept which we called the Operating Envelope. The envelope is created based on the data from a vibration sensor during the transient state. In this paper we consider a single vibration sensor and only the first harmonic amplitude of this signal. To set the acceptance limits within which turbo-set’s dynamic response will be considered as acceptable, we used the cubic spline interpolation coupled with expert judgement. Beyond these limits the state of the turbo-set is considered as unhealthy, so it is an automated fault detection method. In such a case a machine should be a subject to further and deeper diagnostic analysis. The method was validated on the data from the 13K242 type (a 200 MW class turbine) steam turbine. We also proposed a set of parameters to evaluate the severity of malfunction.

Electric Generators for Direct Coupled High Speed Turbo Generators in Distributed Power Systems

ABSTRACT This article addresses various technical challenges in developing high speed, lightweight electric generators for applications in direct coupled high speed generators for distributed power systems. These challenges involve the technologies of electromagnetics, thermodynamics, rotor dynamics, and engineering assembly practices. How those challenges are being addressed and the results of activities to date relating to generators from several hundred kilowatts to a few megawatts will be discussed. Current status and the test data relating to these generators will be presented. While the requirements of power and voltage levels as well as the duty cycle vary, the applicable generator technology is mainly impacted by the power level. The electric generator is typically driven by a high speed turbine. The operating speeds of the turbine and the mechanical and thermal interfaces with the generator have a substantial impact on the design details of the generator. The best approach in interfacing the high speed turbine to the generator is to directly couple the two by means of a mechanical coupling and exclude the need for gear, belt or other mechanical transmission systems. The high speed turbine operates most efficiently at their rated speed, which varies with rated power output. Thus while a typical 200 kW turbine may operate at 60000 rpm, a MW class turbine may operate in the range of 15000 rpm to 30000 rpm. It is often details such as the coupling and mounting arrangement and the suitability of coolants and lubricants that affect the generator design and impact the weight and size of the final product. Selection of the appropriate generator technology is highly dependent on the operating speed requirements. Examples of specific power and speed ratings as well as suitability of generator technologies such as permanent magnet (PM), wound rotor synchronous, switched reluctance (SR) and induction will be discussed. Current development programs for 30 kW to 2.5 MW power generators will be presented.

Electric Generators for Direct Coupled High Speed Turbo Generators in Distributed Power Systems

This article addresses various technical challenges in developinghigh speed, lightweight electric generators for applications in directcoupled high speed generators for distributed power systems. Thesechallenges involve the technologies of electromagnetics, thermodynam-ics, rotor dynamics, and engineering assembly practices. How those chal-lenges are being addressed and the results of activities to date relating togenerators from several hundred kilowatts to a few megawatts will bediscussed. Current status and the test data relating to these generatorswill be presented.While the requirements of power and voltage levels as well as theduty cycle vary, the applicable generator technology is mainly impactedby the power level. The electric generator is typically driven by a highspeed turbine. The operating speeds of the turbine and the mechanicaland thermal interfaces with the generator have a substantial impact onthe design details of the generator.The best approach in interfacing the high speed turbine to the gen-erator is to directly couple the two by means of a mechanical couplingand exclude the need for gear, belt or other mechanical transmissionsystems. The high speed turbine operates most ef ficiently at their ratedspeed, which varies with rated power output. Thus while a typical 200kW turbine may operate at 60000 rpm, a MW class turbine may oper-ate in the range of 15000 rpm to 30000 rpm. It is often details such asthe coupling and mounting arrangement and the suitability of coolantsand lubricants that affect the generator design and impact the weight
 and size of the final product. Selection of the appropriate generatortechnology is highly dependent on the operating speed requirements.Examples of speci fic power and speed ratings as well as suitability ofgenerator technologies such as permanent magnet (PM), wound rotorsynchronous, switched reluctance (SR) and induction will be discussed.Current development programs for 30 kW to 2.5 MW power generatorswill be presented