Turbomachine Overspeed Protection Testing During Shutdown

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Solution Overview

Problem

Current overspeed testing methods for turbomachines introduce high thermal and mechanical stresses, require full-speed-no-load operation, and necessitate premature maintenance and energy delays, leading operators to avoid testing due to inefficiencies and costs.

Innovation Solution

A method and system for automatically testing the overspeed protection system of a turbomachine during a shutdown sequence, which adjusts the overspeed trip set point to minimize thermal transients and avoids full-speed-no-load operation, allowing for remote or local control and automatic testing without requiring a turbomachine restart.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual speed adjustment is used to test overspeed protection system, then the overspeed protection system can be tested, but high thermal and mechanical stresses are introduced to the turbomachine

Engineering Contradiction:

Improveoverspeed protection system testingVSAvoidthermal and mechanical stresses

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control system automatically adjusts the shaft speed to the overspeed condition without manual intervention, preparing the test conditions in advance and executing the speed adjustment before the actual overspeed event occurs, thereby avoiding the harmful effects of manual speed adjustment

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual mechanical speed adjustment with an automated control system that electronically controls the shaft speed, substituting the mechanical manual adjustment process with an automated control mechanism that can precisely manage the speed increase and reduce thermal and mechanical stresses

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If turbomachine operates at full-speed-no-load condition for testing, then overspeed testing can be performed, but energy is consumed without generating revenue

Engineering Contradiction:

Improveoverspeed protection system testingVSAvoidfuel and electricity consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent performs the overspeed protection test by partially increasing the shaft speed above normal operating speed rather than requiring full-speed-no-load operation, achieving sufficient test conditions with less extreme speed increase, thereby reducing energy consumption while still validating the protection system

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The automated control system maintains continuous monitoring and control throughout the test process, ensuring that the turbomachine remains in a controlled state that can quickly transition back to revenue-generating operation, minimizing the duration of non-productive testing and associated energy consumption

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If turbomachine trips during overspeed testing near normal operating speed, then overspeed protection is verified, but maintenance interval is decreased and re-start is required

Engineering Contradiction:

Improveoverspeed protection verificationVSAvoidmaintenance interval and re-start time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The control system dynamically adjusts the shaft speed during testing, automatically controlling the rate and extent of speed increase to verify the overspeed protection trigger point while managing the thermal and mechanical stress profiles, thereby extending maintenance intervals and reducing the need for immediate re-start operations

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7716971B2Method and system for testing an overspeed protection system during a turbomachine shutdown sequence

Publication Date: 2010.05.18 GE INFRASTRUCTURE TECH LLC

AI summary

A method and system of testing an overspeed protection system of a turbomachine. The method and system may include providing an overspeed protection system on a turbomachine that may have a single or multiple shafts; determining whether the speed the shaft or shaft(s) exceeds a shutdown value; changing an overspeed trip value of the turbomachine; and determining whether the overspeed protection system would operate to trip the turbomachine.