Generator Load State Detection via Power Imbalance

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Solution Overview

Problem

Generators in load control mode experience oscillations and mechanical damage due to unexpected load interruptions, as they cannot accurately detect such events without relying on parameter thresholds that vary by generator type and conditions, leading to inaccurate detection.

Innovation Solution

A method and device that calculate a power imbalance value by comparing actual load power with target output power, determining an unexpected load interruption based on this value, and sending indication information only if specific conditions are met to avoid false alarms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If parameter thresholds are used to detect load interruptions, then detection can be implemented, but detection accuracy deteriorates due to variation in generator types and conditions

Engineering Contradiction:
Improveload interruption detection reliabilityVSAvoiddetection precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the detection parameter from multiple generator-specific parameters (voltage, current, frequency, power) with varying thresholds to a single universal parameter: rotational speed. The rotational speed threshold is set at 105% of rated speed, which is applicable to all generator types and operating conditions, eliminating the need for generator-specific threshold calibration and improving both reliability and precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a universal detection method that works across different generator types and operating conditions by using rotational speed as the common parameter. This single parameter approach makes the protection system universally applicable to all generators in load control mode, regardless of their specific characteristics or operating conditions, thereby improving detection reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple parameter thresholds are monitored, then detection coverage is improved, but device complexity increases

Engineering Contradiction:
Improvedetection coverageVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the essential detection function from a complex multi-parameter monitoring system and isolates it to a single critical parameter: rotational speed. By removing unnecessary parameters (voltage, current, frequency, power) and their associated threshold settings, the system achieves simplified implementation while maintaining effective load interruption detection coverage.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of monitoring multiple parameters and looking for abnormal combinations, the patent inverts the approach by monitoring a single parameter (rotational speed) and detecting load interruptions through its normal increase pattern. This inversion simplifies the detection logic from complex multi-parameter analysis to simple single-parameter threshold comparison.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3872980B1Power balance function against inadvertent load shedding
Publication Date: 2023.04.05 SIEMENS AG
  • EP3872980B1 patent drawingFigure 1
  • EP3872980B1 patent drawingFigure 2
  • EP3872980B1 patent drawingFigure 3

AI summary

The present invention provides a generator load state detection method and device and a computer-readable medium and relates to the technical field of power engineering. The generator load state detection method comprises: acquiring the load power of a target generator, wherein the target generator is connected to a load with a set of cables, the target generator is in load control mode and the load power is used to represent the actual output power of the target generator; acquiring the target output power of the target generator, wherein the target output power is used to represent the power required by the target generator to output in load control mode; calculating the difference between the load power and the target output power as a power imbalance value; determining the load state of the target generator according to the power imbalance value. The solution can accurately detect whether the load of a generator is unexpectedly interrupted.