Wind Turbine Pitch System Overvoltage Protection
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Solution Overview
Problem
Modern wind turbine pitch systems are vulnerable to overvoltages in the power network, which can cause them to malfunction or fail, even with emergency power supplies, leading to potential damage or safety hazards.
Innovation Solution
The method involves using semiconductor switching elements to block current flow from the supply network into the pitch system's input rectifiers when overvoltages are detected, allowing the pitch drives to be powered by emergency storage devices, and employing overvoltage protection devices and monitoring modules to manage and alert for potential threats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If overvoltage protection devices (varistors, suppressor diodes) are used to protect the pitch system, then the pitch system is protected against overvoltages, but the pitch system becomes sensitive to even small overvoltages and initiates emergency procedures immediately
Solution Approach 1:
The patent introduces semiconductor switching elements as an intermediary component between the supply network and the pitch system. These switching elements act as a controlled gate that can selectively block overvoltage while allowing normal operation to continue, thereby mediating between the harmful overvoltage and the protected pitch system without triggering immediate emergency procedures
Solution Approach 2:
The patent changes the voltage threshold parameter for initiating emergency procedures. Instead of triggering immediately at any overvoltage detection, the system now allows continued operation during moderate overvoltages by adjusting the threshold at which emergency feathering is initiated, based on the controlled blocking capability of the semiconductor switching elements
2Reliability
If the pitch system is equipped with emergency power storage devices, then the pitch system can operate during network failures, but the system complexity increases
Solution Approach 1:
The patent makes the emergency power storage devices multi-functional by using them for both their traditional purpose (power supply during network failure) and a new purpose (power supply during controlled overvoltage blocking). The same energy storage components serve dual functions, reducing the need for additional specialized equipment
Solution Approach 2:
The patent implements preliminary blocking action using semiconductor switching elements that can preemptively block overvoltage before it reaches the pitch system. This preliminary protective measure allows the system to prepare for and manage overvoltage conditions without immediate emergency response
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach protects the pitch system from overvoltages, enabling continued operation during moderate network overvoltages and ensuring safe feathering of rotor blades, even in the absence of external power, thereby preventing damage and ensuring safety.
Implementation Method 1
each input rectifier has at least one semiconductor switching element with which a flow of current from the supply network into the respective input rectifier can be blocked
Implementation Method 2
each pitch drive is connected to an emergency power storage device, whereby each pitch drive can be supplied with electric power by the emergency power storage device that is connected to it
Data Source
AI summary
A method for the operation of a pitch system of a wind turbine with at least one rotor blade, wherein the pitch system has at least one input rectifier and at least one pitch drive, each rotor blade can be rotated around its longitudinal axis by the one pitch drive or by at least one of several pitch drives, each input rectifier is supplied with alternating voltage by a supply network, and each pitch drive is supplied with electric power by the one input rectifier or by at least one of several input rectifiers, each pitch drive is connected to an emergency power storage device, whereby each pitch drive can be supplied with electric power by the emergency power storage device that is connected to it.