Grid Voltage Recovery via Dynamic Reactive Current Control

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Solution Overview

Problem

Existing wind power generating systems face challenges in reliably and swiftly restoring utility grid voltage to reference levels following a grid failure, as the reactive current supply based on pre-simulation tables may lead to voltage saturation and insufficient reactive current delivery.

Innovation Solution

A generating apparatus with a voltage detecting section and a control section that adjusts reactive current based on real-time voltage correlation information, allowing for increased reactive current supply or absorption when the grid voltage is outside a predetermined range after a set time, ensuring swift stabilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If reactive current is supplied based on pre-determined voltage current correlation information from simulations, then voltage recovery follows simulated performance, but the voltage may become saturated and stabilized before recovering to reference voltage in actual operation

Engineering Contradiction:
Improvevoltage recovery reliabilityVSAvoidvoltage recovery precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The control section continuously monitors the actual voltage of the utility grid and compares it with the reference voltage. Based on this feedback, the control section dynamically adjusts the reactive current supply by modifying the voltage current correlation information, ensuring the voltage recovers to the reference level without saturation. This closed-loop feedback mechanism resolves the discrepancy between simulated and actual voltage recovery performance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes the voltage current correlation information parameters based on actual operating conditions. When voltage saturation is detected, the control section modifies the correlation parameters to increase reactive current supply beyond the pre-determined values, enabling the voltage to recover to the reference level. This parameter adaptation resolves the contradiction between following simulation guidelines and achieving precise voltage recovery in actual conditions.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the voltage current correlation information is updated to increase reactive current supply, then voltage recovery speed increases, but the control system complexity increases

Engineering Contradiction:
Improvevoltage recovery speedVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The voltage current correlation information is transformed from a static pre-determined table into a dynamic structure that can be automatically adjusted during operation. The control section modifies the correlation parameters in real-time based on voltage recovery progress, enabling faster voltage recovery without requiring a completely complex control system. The dynamics principle allows the system to adaptively increase reactive current supply when needed while maintaining manageable control complexity through structured parameter modification.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2432113B1Power generating device and control method therefor
Publication Date: 2015.02.25 MITSUBISHI HEAVY IND LTD
  • EP2432113B1 patent drawingFigure 1
  • EP2432113B1 patent drawingFigure 2~3
  • EP2432113B1 patent drawingFigure 4

AI summary

It is an object to reliably and swiftly restore voltage of a utility grid, which decreased due to a utility grid failure or the like, to reference voltage. A generating apparatus includes: a generator connected to a utility grid; a voltage detecting section for detecting voltage of a utility grid 2; and a control section 21 for determining reactive current corresponding to the voltage obtained from the voltage detecting section 27 based on voltage current correlation information in which the voltage of the utility grid 2 and the reactive current to be supplied to the utility grid 2 are correlated with each other and controlling the electric power converting section 27 to regulate the reactive current to be supplied to or absorbed from the utility grid 2. The apparatus further includes an information changing section 22 for changing the voltage current correlation information to increase an amount of the reactive current with respect to a variation in the voltage in the voltage current correlation information, in the case where the voltage of the utility grid is not in a predetermined range set in advance after a predetermined time period has passed since the voltage of the utility grid varied by a predetermined amount or more.