Wind Turbine HVRT Testing via On-Load Transformer and Short-Circuit Unit
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Solution Overview
Problem
Current methods for testing wind turbines' high voltage ride through (HVRT) capability at the medium-voltage level are inefficient due to the need for circuit breakers and require disconnecting the test unit, significantly increasing test times and production losses.
Innovation Solution
A method utilizing an on-load switchable transformer to increase voltage and a short-circuit test unit with series impedance to dynamically adjust voltage, allowing for HVRT testing without disconnecting the power generation unit, enabling continuous operation and reduced test times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transformer with winding taps and power electronic IGBT switches is used to generate transient overvoltages, then HVRT capability can be tested, but the solution cannot be economically implemented at the medium-voltage level due to the lack of circuit breakers
Solution Approach 1:
The patent replaces mechanical circuit breakers with power electronic switches (IGBTs) for voltage generation and control. This substitution enables HVRT testing at medium-voltage levels by using semiconductor-based switching instead of mechanical breaker systems, making the solution economically implementable while maintaining testing reliability
2Manufacturing precision
If the transformer transformation ratio is set after activation without load, then the transformer can be properly configured, but the test unit must be switched off during the pre-charging process which significantly increases test times
Solution Approach 1:
The patent performs the transformation ratio configuration in advance during the manufacturing or setup phase, rather than requiring post-activation adjustment. This preliminary setup eliminates the need to switch off the test unit during pre-charging, significantly reducing test time while ensuring proper transformation ratio configuration before actual HVRT testing begins
3Reliability
If mechanical circuit breakers are used to activate the short-circuit reactor, then the short-circuit test unit can be controlled, but the switching characteristics are not comparable to medium-voltage switch requirements
Solution Approach 1:
The patent replaces mechanical circuit breakers with power electronic switches (IGBTs) for controlling the short-circuit reactor. This substitution provides switching characteristics that are comparable to medium-voltage switch requirements, enabling proper integration and control while maintaining reliability of short-circuit testing functionality
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 allows for time-optimized testing of wind turbines with dynamic overvoltages and undervoltages while maintaining the power generation unit in production mode, reducing measurement time and production losses.
Implementation Method 1
an on-load switchable transformer (20) increases a voltage of the power generation side
Implementation Method 2
a short-circuit test unit (12) with a series impedance (Z) connected with a series and a longitudinal impedance in order to reduce the boosted voltage
Data Source
Figure 1
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Figure 4
AI summary
Device and method for testing a power generation unit connected to an electrical supply network (10), in particular a wind turbine (16), which has a short-circuit test unit (12) switchable between the power generation unit and the supply network (10) with a longitudinal impedance (Zk) and a series impedance (ZN) and a transformer (20) switchable between the short-circuit test unit (12) and the supply network (10), which is steppable under load.The procedure comprises the following steps: - Increasing the voltage at the power generation unit by means of a load-switchable transformer, - Switching on a short-circuit test unit with a series impedance and a longitudinal impedance to reduce the increased voltage, - Switching off the short-circuit test unit for a defined first period of time after transient switching operations have subsided, and, - after the first period of time has elapsed, switching on the short-circuit test unit for a defined second period of time to reduce the increased voltage.