Diagnosis method for detecting ageing symptoms in a steam turbine

• US 20040010387A1
• Filed: 02/19/2003
• Published: 01/15/2004
• Est. Priority Date: 08/17/2000
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Girbig, Paul
• Granted Patent: US 6,910,364 B2
• Time in Patent Office: Days
• US Class Current: 702/113
• CPC Class Codes: G07C 3/00 Registering or indicating the condition or the working of machines or other apparatus, other than vehicles

Abstract

A diagnosis method is for detecting ageing symptoms in a steam turbine. The efficiency and the steam flow rate of an aged steam turbine is compared to the efficiency and the steam flow rate of a relatively new steam turbine. The efficiency and the steam flow rate are calculated using readings at several operating points on the steam turbine. The time history of the efficiency and steam flow rates applied in contrast to parameters such as the peripheral Mach number, pressure figure and adjustment of the inlet valve provide information on the extent of ageing of the steam turbine.

Claims

1. A diagnostic method for the detection of aging phenomena in a steam turbine (2), in which the efficiency (W) and/or the steam throughput coefficient F of the steam turbine (2) is calculated from measurements of state variables of the steam turbine (2) at a first time point (t₁) and at a later second time point (t₂) at a plurality of operating points of the steam turbine (2), an operating point being determined in each case by a value of the parameters circumferential Mach number (M_u), pressure number (D) and inlet valve position (S), and the extent of the aging of the steam turbine (2) is concluded from the change in the efficiency (W) and/or in the steam throughput coefficient (F) from the first time point (t₁) to the second time point (t₂) as a function of the operating point.

2. The diagnostic method as claimed in claim 1, characterized in that

a) the efficiency (W) and/or the steam throughput coefficient (F) of the steam turbine (2) are/is calculated at a plurality of first operating points of the steam turbine (2) at a first time point (t₁),

b) a first scalar field (31) is calculated from these first measurement values by interpolation,

c) the efficiency (W) and/or the steam throughput coefficient (F) are/is calculated at a plurality of second operating points of the steam turbine (2) at a second time point (t₂),

d) a second scalar field (41) is calculated from these second measurement values by interpolation, and

e) the extent of the aging of the steam turbine (2) is concluded from the change in time from the first scalar field (31) to the second scalar field (41).

3. The diagnostic method as claimed in claim 1 or 2, characterized in that the efficiency (W) and/or the throughput coefficient (F) are/is calculated for a subregion of the steam turbine (2) and the extent of the aging of the subregion is concluded from these.