Wind Turbine Generator Grid Reconnection Control
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Solution Overview
Problem
Wind turbine generators experience delays in reconnecting to the grid after power loss due to the need for auxiliary low-voltage power sources to reach operational temperature, leaving the main circuits unprotected during this time, especially in cold climates.
Innovation Solution
A method and apparatus for automatically disconnecting and reconnecting wind turbine generators to the grid using an auxiliary power supply, such as a diesel generator or batteries, which allows for immediate power restoration to auxiliary circuits upon grid voltage recovery, ensuring continuous protection of the main circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a UPS with heater is used to supply power to auxiliary circuits, then the auxiliary circuits can operate in cold temperatures, but there is a significant delay (up to 1 hour) before the auxiliary circuits become functional after grid power returns
Solution Approach 1:
The system performs preliminary actions by maintaining the UPS circuitry in a standby state with pre-charged batteries and pre-heated conditions. When grid power returns, the auxiliary circuits can immediately become functional because the necessary preparatory actions (heating, charging) were performed in advance during the power outage period.
Solution Approach 2:
The invention changes the operational parameters of the power supply system by switching from grid power to auxiliary power source (batteries) and adjusting temperature parameters through heating elements. This allows the system to maintain functional temperatures and readiness states despite external temperature conditions and power availability changes.
2Loss of energy
If the auxiliary circuits are kept unpowered during grid voltage recovery, then power consumption is reduced, but the main circuitry remains unprotected during this time
Solution Approach 1:
The invention introduces an intermediary power supply system consisting of batteries and control circuits that mediate between the grid power and the auxiliary circuits. This intermediary system provides bridging power during the transition period, ensuring continuous protection of main circuitry without requiring the auxiliary circuits to be fully powered immediately upon grid recovery.
Solution Approach 2:
The system provides beforehand cushioning by maintaining charged batteries ready to supply power to auxiliary circuits during the critical transition period when grid power returns but auxiliary circuits are not yet fully operational. This cushioning power supply ensures continuous protection without immediate full power consumption.
3Reliability
If manual reconnection is required after grid power returns, then safety can be ensured, but service personnel must access the circuitry in the tower which is inconvenient for off-shore wind turbines
Solution Approach 1:
The invention implements self-service by enabling the wind turbine system to automatically reconnect to the grid after power restoration without requiring manual intervention. The control system autonomously monitors grid power availability, manages the auxiliary power supply, and performs reconnection operations, making the system self-sufficient and eliminating the need for service personnel to access the tower.
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 solution ensures that the wind turbine generator remains disconnected until auxiliary circuits are fully functional, providing continuous protection and reducing the risk of prolonged downtime by eliminating the need for temperature-dependent UPS activation delays.
Implementation Method 1
the UPS is normally supplied with a heater for maintaining the temperature of the associated circuitry above this level
Implementation Method 2
a low-voltage electricity supply, which is typically derived from a transformer connected to the high-voltage grid
Data Source
AI summary
A wind turbine generator (WTG) is connected to an electricity grid via a switchgear. A control system disconnects the WTG from the grid in the event of a fault and also if the grid voltage falls below its normal value for a predetermined time, to prevent the WTG from being connected when the control system is not functional. A back-up generator is started manually to recharge a battery and supply power to the control system . When the control system is fully functional, the WTG is manually re-connected to the grid. Alternatively, the control system enters a sleep mode during which the grid voltage continues to be monitored. When the grid voltage returns, the control system reverts to its wake mode and draws sufficient power from the battery to become fully functional, at which point the WTG is re-connected to the grid.