Subtransient Current Suppression for Aircraft Power Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft power systems face challenges in protecting against high subtransient fault currents and overvoltage transients, leading to the need for oversized protective devices that increase weight and operational costs, and existing materials used for backup protection can oxidize over time.
Innovation Solution
A method and apparatus that include a subtransient current detector and suppressor, which directs subtransient currents to ground for a time delay, and an overvoltage transient detector and suppressor, which identifies and suppresses overvoltages, using a switch controller to manage these conditions, thereby reducing the size of protective devices needed and preventing undesired effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If larger protective and power control devices are used to withstand higher fault current levels, then the capability to resist fault currents is improved, but aircraft weight increases
Solution Approach 1:
The suppressor circuit activates before the main protective devices need to handle the full subtransient fault current magnitude. By preemptively directing a portion of the subtransient fault current to ground during the critical first half-cycle, the suppressor reduces the peak current stress on generators and protective devices, allowing these components to be sized for lower current levels and thereby reducing aircraft weight.
Solution Approach 2:
The suppressor circuit acts as an intermediary component between the fault source and the main protective devices. It provides a parallel current path to ground that mediates the subtransient fault current, preventing the full current magnitude from reaching the generators and main protective devices during the critical initial period.
2Reliability
If contact materials are used to withstand subtransient fault currents, then fault current capability is improved, but the materials can oxidize over time
Solution Approach 1:
The invention converts the harmful subtransient fault current into a beneficial effect by using it to trigger the suppressor circuit, which then directs the current to ground in a controlled manner. This approach protects the contact materials from oxidation by preventing them from being exposed to the full subtransient current stress that would cause oxidative degradation.
Solution Approach 2:
The suppressor circuit serves as an intermediary that protects contact materials from direct exposure to subtransient fault currents. By providing an alternative current path to ground, it prevents the harmful oxidative interaction between the contact materials and the high-magnitude subtransient current.
3Reliability
If oversized protective devices are used to protect against subtransient currents, then protection capability is improved, but device size and cost increase
Solution Approach 1:
The suppressor circuit performs preliminary action by activating during the first half-cycle of subtransient fault current to reduce the peak current magnitude. This preliminary current reduction allows downstream protective devices to be sized smaller while maintaining adequate protection capability, thereby reducing overall device complexity and cost.
Solution Approach 2:
The protection system is segmented into two functional parts: the suppressor circuit that handles the subtransient current component during the critical initial period, and the main protective devices that handle steady-state and sustained fault conditions. This segmentation allows each component to be optimized for its specific function, reducing the need for oversized general-purpose protective devices.
Data Source
AI summary
A system and method for suppressing a subtransient current and an overvoltage in a power system. A subtransient current is identified at a location in the power system. The subtransient current at the location in the power system is directed to ground for a time delay in response to identifying the subtransient current at the location in the power system. Directing the subtransient current at the location in the power system to ground is ceased in response to identifying an end of the time delay. An overvoltage is identified at the location in the power system. The overvoltage at the location in the power system is suppressed in response to identifying the overvoltage at the location in the power system.