Wind Turbine Dump Load Resistor Grid Loss Control
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Solution Overview
Problem
Wind turbines experience unbalanced rotation and excessive force application due to rapid loss of grid load, leading to potential over-speeding and severe braking, which can cause high load forces and bending moments on the structure.
Innovation Solution
Incorporating a dump load resistor into the power circuit of the wind turbine that applies an electrically adsorbing load to the generator during grid loss, slowing rotor speed and reducing the need for severe braking, allowing the turbine to withstand smaller grid loss loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a severe braking procedure is initiated to avoid rotor over-speeding after grid loss, then rotor speed is controlled, but high load forces and bending moments are applied to the wind turbine structure
Solution Approach 1:
The dump load resistor is pre-positioned in the power circuit and can be immediately activated upon grid loss detection. This preliminary preparation allows the system to apply electrical braking load before mechanical braking is initiated, reducing the severity of forces required from the mechanical braking system and structure.
Solution Approach 2:
The dump load resistor acts as an intermediary energy absorption mechanism between the generator and the mechanical braking system. It absorbs excess electrical energy through resistive heating, thereby reducing the energy that must be dissipated by mechanical brakes and reducing the corresponding structural load forces.
2Productivity
If the grid load is lost abruptly, then the generator is unloaded, but the wind turbine becomes unbalanced and rotor accelerates rapidly
Solution Approach 1:
The dump load resistor serves as an intermediary load that maintains electrical loading on the generator during grid loss events. By providing a controlled electrical load path, it prevents the abrupt unloading that causes rotor acceleration and maintains system balance.
Solution Approach 2:
The invention replaces the need for mechanical balancing mechanisms with an electrical solution. Instead of using mechanical flywheels or inertia-based systems to maintain rotor speed stability, the dump load resistor provides electrical damping to maintain rotational equilibrium.
3Strength
If traditional wind turbine structures are designed to withstand forces from grid loss, then structural strength is sufficient, but thick walls and large connection bolts are required
Solution Approach 1:
By pre-positioning the dump load resistor in the power circuit and designing it to activate immediately upon grid loss detection, the system prepares an energy absorption path before excessive rotor speed and corresponding structural forces can develop. This reduces the peak forces that the tower structure must be designed to withstand.
Solution Approach 2:
The invention converts the potentially harmful rapid rotor acceleration and high structural loads into a beneficial controlled energy dissipation process through the dump load resistor. The electrical energy that would otherwise cause mechanical stress is converted to thermal energy in the resistor, protecting the structure from excessive forces.
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
The dump load resistor prevents rapid rotor acceleration and excessive force application, enabling wind turbines to be designed for smaller grid loss loads, reducing structural stress and maintaining stability.
Implementation Method 1
a dump load resistor 32 to dissipate power produced by the generator 20
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A wind turbine braking system (10) including: a wind turbine (16) including turbine blades (18) and a control system (28); a generator (20) coupled to the turbine blades; a generator converter (24) coupled to the generator and connectable to a utility power grid (26); at least one dump resistor (32) coupled to the generator and generator converter, and if the utility power grid losses power, the dump resistor applying an electrical load to the generator converter.