SHEAR RESISTANT METHOD AND DEVICE FOR MONITORING THE HEART OF A STATOR TURBOGENERATOR DURING THE OPERATION PROCESS

Abstract

Purpose. The aim of the work is to create a new method and device for monitoring the integrity of the coupling prisms, which will allow, with minor improvements in the design of individual measuring prisms, to obtain information on the state (damage) of all the coupling prisms and, therefore, on the degree of pressing of the stator iron as a whole. Methodology. The tensometric method of physical modeling, analytical calculations. Findings. An experimental model of a device for monitoring and diagnosing the state of pressing of a generator stator core was developed and investigated on a physical model of a 500 MW turbogenerator. The advantage of the control method with the use of sensors based on strain gauges is determined by the relatively low cost of the latter, and with the right choice of elastic element and design, it is possible to monitor the mounting elements of the stator core with a fairly high degree of accuracy. The tests carried out with the simulation of the destruction of prisms by removing from them the load on the models of the stator of the turbogenerator in laboratory conditions showed a satisfactory agreement between the results of the experiment and theoretical calculations. The data on the change in the stress-strain state of the rods of the model were evaluated using strain gauges pasted in a certain way on the measuring stud. The main advantage of the proposed method of controlling forces in the clamping prism is the fact that measurements can be made on a stopped turbogenerator without removing the end shields, since the forces in the clamping prisms, taking into account their changes, in the event of damage to any prism remain inoperative. The introduction of the developed method and device will not only prevent emergencies associated with the breakage of the coupling prisms, but also provide an opportunity to exercise constant monitoring of the state of pressing of the stator core. Originality. A new method for controlling the state of coupling prisms of the stator core without removing the side panels of the turbogenerator is proposed, and for the first time theoretically substantiated the possibility of using a mathematical apparatus to determine the location of damage and the number of prisms with loosened nuts or broken threads. Practical value. On the basis of fundamental results, a method for monitoring and diagnosing the state of pressing the stator core of a turbogenerator using special measuring studs has been developed. The proposed method will make it possible to determine the number of prisms that are damaged, and, therefore, to predict the timing of the subsequent repair without the output of the generator to be repaired, according to the readings of the sensors.

Keywords

• turbogenerator
• end zone
• stator winding
• pressing
• strain gauge