PT Electronic Load Damping for Ferromagnetic Resonance Control
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Solution Overview
Problem
Existing methods for eliminating ferromagnetic resonance in potential transformers (PTs) face challenges such as core saturation and overload during single-phase grounding, particularly due to the discrete nature of resistance values used in active resonance elimination systems, which leads to ineffective real-time tracking and potential damage to the transformer.
Innovation Solution
A PT ferromagnetic resonance elimination method that actively inputs resistance through an electronic load, utilizing a resistance matching algorithm and PID control strategy, replacing traditional rheostats with an electronic load to dynamically adjust resistance and prevent resonance, thereby avoiding core saturation and overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small damping resistor is input to eliminate resonance, then the resonance elimination effect is improved, but the potential transformer core saturates and windings overload
Solution Approach 1:
The patent replaces fixed resistance values with dynamically adjustable resistance through electronic load and PID control. The system continuously monitors resonance conditions and adjusts the damping resistance in real-time, transitioning from static to dynamic resistance control to optimize both resonance elimination and prevent core saturation
Solution Approach 2:
The patent changes the resistance parameter dynamically based on system conditions. By using electronic load to vary resistance values continuously rather than using fixed discrete values, the system adapts the damping parameter to match actual resonance intensity, preventing excessive current that causes core saturation while maintaining effective resonance suppression
2Device complexity
If discrete resistance values are used in active resonance elimination, then the system structure is simplified, but real-time tracking effectiveness deteriorates
Solution Approach 1:
The patent replaces mechanical rheostats with electronic load for resistance adjustment. This substitution eliminates the need for discrete mechanical resistance steps while enabling continuous, precise resistance control through electronic means, achieving both simplicity and real-time tracking effectiveness
Solution Approach 2:
The system transitions from static discrete resistance values to dynamic continuous resistance adjustment. The electronic load controlled by PID algorithm provides real-time resistance variation matching resonance conditions, significantly improving tracking effectiveness while maintaining system simplicity
3Ease of operation
If the damping resistor is connected in parallel during normal operation, then the normal operation is maintained, but resonance energy cannot be effectively consumed when voltage asymmetry occurs
Solution Approach 1:
The patent implements dynamic resistance control that adapts to system state. During normal operation, the electronic load maintains high resistance (effectively disconnected) to avoid interference. When voltage asymmetry or resonance is detected, the resistance is dynamically adjusted to optimal damping values for effective resonance suppression
Solution Approach 2:
The system uses PID control with feedback from voltage monitoring to dynamically adjust resistance. The control algorithm continuously monitors system state and adjusts the damping resistance accordingly, ensuring optimal performance both during normal operation and fault conditions
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 method effectively addresses the contradiction between resonance elimination resistance and winding overload, allowing for precise and real-time adjustment of resistance to prevent ferromagnetic resonance, ensuring the transformer operates without overload and reducing the risk of damage.
Implementation Method 1
The method of damping resonance is to increase the system damping, that is, to connect a resistor with an appropriate magnitude in series at an opening of an open delta so as to consume resonance energy
Implementation Method 2
A nonlinear core of a potential transformer is the root cause of resonance. An electromagnetic potential transformer can be understood as an inductive element with a core. Because the core is nonlinear, when a system is subjected to a certain disturbance, an exciting current changes, and an inductance value of the transformer changes
Implementation Method 3
The smaller the resistance input for eliminating resonance, the better the effect of eliminating resonance. The disadvantage is that it is easy to cause core saturation, thus overloading a certain winding of the potential transformer
Implementation Method 4
based on a resistance matching algorithm and a PID control strategy, constructing a resonance elimination control system
Data Source
AI summary
The present disclosure relates to the technical field of potential transformer (PT) ferromagnetic resonance elimination, in particular to a PT ferromagnetic resonance elimination method implemented by actively inputting resistance through an electronic load, including the following steps: setting up a PT, and determining a mapping relationship; constructing a resonance elimination control system; and designing the electronic load as an active resonance elimination device. The present disclosure overcomes a contradiction between a magnitude of resonance elimination resistance and winding overload in a PT open delta during single-phase-to-earth fault and fault clearance, and effectively avoids the technical problems of difficult distinguishing between single-phase-to-earth fault characteristics and power frequency resonance characteristics and causing resonance in a single-phase-to-earth fault process. Compared with previous disclosure designs, the present disclosure directly measures parameters, and is simple in algorithm, low in computational complexity, rapid in arithmetic speed, high in precision and less in error.