Wind Turbine Converter Over-Current Margin Fault Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional wind turbine converter systems face inefficiencies during faults, as they can only operate at reduced power levels, leading to decreased energy production and increased maintenance needs, especially in remote locations like offshore wind parks.
Innovation Solution
The implementation of a method that allows wind turbines to operate in two modes: fully-functional and faulty-converter modes, utilizing over-current margins to compensate for converter failures by increasing active current production and reducing reactive current production, while also employing low-voltage and low-temperature margins to enhance energy output during faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If converters are dimensioned only for nominal active current, then device complexity is reduced, but active power production is lost during converter faults
Solution Approach 1:
The converters are pre-dimensioned with an over-current margin capability before any fault occurs. This preliminary design decision enables the converters to handle higher currents than their nominal rating when needed, without requiring additional hardware or complex reconfiguration during fault conditions. The margin is built into the converter design from the outset.
Solution Approach 2:
The invention changes the operational parameters of the converters by allowing them to operate beyond their nominal current rating when in faulty-converter mode. The controller dynamically adjusts the current parameters, enabling the remaining healthy converters to produce additional active current by utilizing the pre-established over-current margin, thus maintaining higher power output during faults.
2Reliability
If converters produce reactive current on top of nominal active current, then grid support capability is improved, but available current margin for active power during faults is reduced
Solution Approach 1:
The invention implements dynamic switching between different operational modes. In fully-functional mode, converters operate with both active and reactive current production. Upon detecting a converter fault, the controller dynamically transitions the system to faulty-converter mode, where the operational characteristics change: reactive current production is reduced or eliminated, and the remaining converters increase their active current output by utilizing the freed-up current margin. This dynamic adaptation optimizes performance for the current system state.
Solution Approach 2:
The invention applies partial action by selectively maintaining or reducing reactive current production depending on the operational mode. In faulty-converter mode, rather than maintaining full reactive current support, the system partially sacrifices reactive power capability to free up current capacity for active power production, ensuring that the most critical function (active power delivery) is prioritized during fault conditions.
3Reliability
If wind turbines operate at reduced power levels during converter faults, then converter overload is prevented, but energy production is decreased
Solution Approach 1:
The over-current margin capability serves multiple functions: it provides headroom for reactive current production during normal operation, enables increased active current output during faults, and prevents overload of the remaining converters. This multi-functional design allows the same hardware capacity to serve different purposes depending on the operational mode, maximizing both reliability and productivity.
Data Source
Figure 1
Figure 2~3b
Figure 4~5
AI summary
A wind turbine is arranged to operate in a fully-functional converter mode and a faulty-converter mode. A plurality of converters are arranged to share electric current in the fully-functional converter mode. The converters are dimensioned not only to operate at nominal active current but to provide an over-current margin to enable reactive current to be produced on top of the nominal active current in the fully-functional converter mode. In the fully-functional converter mode the converters are caused to produce reactive current on top of the nominal active current. In response to a fault of one or more of the converters, operation is changed from the fully-functional converter mode to the faulty-converter mode. In the faulty-converter mode, one or more other converters of the converter system are caused to produce additional active current by using their over-current margin to compensate at least partly for a reduction of active-current production due to the fault of one of the converters, and to reduce the reactive-current production by the other converter correspondingly.