Pump Turbine S-Characteristic Detection for Timely Speed Regulation

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Solution Overview

Problem

Existing methods for identifying the S-characteristic region in pump turbines are inaccurate during transition phases, leading to untimely speed regulation and increased accident probability due to unstable operation.

Innovation Solution

A method and apparatus for identifying the S-characteristic of a pump turbine by collecting state parameters, calculating the slope of the relationship curve between rotation speed and flow rate, and determining positivity or negativity and absolute value of the slope to accurately identify entry into the S-characteristic region.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing methods are used to identify the S-characteristic region, then the identification process is simple, but the identification accuracy is low and timing is delayed

Engineering Contradiction:

Improveidentification accuracyVSAvoididentification method complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The identification method is segmented into multiple distinct steps: collecting state parameters (flow rate, rotation speed), calculating the slope of the relationship curve, determining positivity/negativity and absolute value of the slope, and comparing with preset values. This segmentation allows each step to be optimized independently, improving overall identification accuracy without creating an unduly complex system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The method dynamically calculates the slope based on real-time state parameters and adapts the identification process based on the calculated slope characteristics. The system transitions from static threshold comparison to dynamic slope analysis, enabling timely detection of S-characteristic region entry while maintaining operational simplicity through automated calculations.

Inventive Principle:

Principle #15Dynamics

2Reliability

If existing identification methods are used, then the system operation is simple, but the speed regulation timing is delayed leading to unstable operation

Engineering Contradiction:

Improveoperational stabilityVSAvoidspeed regulation timing

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The method performs preliminary identification of the S-characteristic region by continuously monitoring and calculating the slope of the flow rate-rotation speed relationship curve before the turbine actually enters the unstable region. This preliminary detection enables advance speed regulation, preventing unstable operation rather than reacting after problems occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system establishes a feedback loop where state parameters are continuously collected, the slope is calculated and analyzed, and speed regulation decisions are made based on the identification results. This closed-loop feedback mechanism ensures timely speed regulation adjustments are made in response to detected S-characteristic conditions, improving operational stability.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If the slope calculation method is simplified, then the computation is faster, but the identification accuracy during transition phases deteriorates

Engineering Contradiction:

Improvetransition phase identification accuracyVSAvoidcomputation speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The method changes the analytical parameter from direct flow rate or rotation speed monitoring to slope calculation of their relationship curve. This parameter transformation enables more accurate detection of transition phases into the S-characteristic region, as the slope provides a derivative measure that is more sensitive to changing conditions than the raw parameters alone.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system calculates the slope using multiple state parameters (flow rate, rotation speed) and performs multiple comparisons (positivity/negativity and absolute value against preset values). This partial use of available data and multiple comparison steps improves accuracy during critical transition phases without requiring excessive computational resources, as only key parameters and thresholds are processed.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12584456B2Method and apparatus for identifying S-characteristic of pump turbine, and control method

Publication Date: 2026.03.24 CSG POWER GENERATION CO LTD MAINT & TEST CO

AI summary

The present disclosure discloses a method and an apparatus for identifying an S-characteristic of a pump turbine and a control method. The method for identifying an S-characteristic of a pump turbine includes: collecting a set of state parameters of the pump turbine at a preset time interval, wherein the state parameters comprise a flow rate and a rotation speed of the pump turbine; calculating a slope of a relationship curve between the rotation speed and the flow rate of the pump turbine within a current preset time interval; and determining, according to the positivity or negativity and an absolute value of the slope, whether the pump turbine enters an S-characteristic region.