Transformer Tap Changer Voltage Control for Variable Load Conditions
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Solution Overview
Problem
Existing methods for determining the optimal voltage set point and control policy for automatic voltage regulators in transformers with on-load tap changers do not adapt effectively to changing load circumstances, leading to prolonged and frequent over- and under-voltage situations.
Innovation Solution
A method that dynamically determines the optimal voltage set point and corresponding control policy for automatic voltage regulators by establishing a time window, obtaining network variables and parameters, generating an electrical network model, calculating voltage drops, and setting the control policy, ensuring correspondence between the voltage set point and regulator parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional fixed control policies are used for automatic voltage regulators, then the device complexity is reduced, but the adaptability to changing load circumstances deteriorates, leading to prolonged over- and under-voltage situations
Solution Approach 1:
The patent implements dynamic control policies that automatically adjust voltage set points and control parameters based on real-time load conditions. The system transitions from fixed, static control policies to dynamic policies that adapt to changing network conditions, thereby improving adaptability while managing complexity through automated adjustment mechanisms
Solution Approach 2:
The patent changes control parameters (voltage set points, tolerance bands, response times) based on load circumstances. By dynamically modifying these parameters rather than using fixed values, the system achieves better adaptability to varying load conditions while maintaining manageable complexity through parameter-based control
2Reliability
If frequent tap changes are made to maintain voltage set point, then the voltage stability is improved, but the useful life of the electrical tap changer deteriorates
Solution Approach 1:
The patent applies partial action by making tap changes only when necessary, rather than continuously adjusting to maintain exact voltage set points. By accepting small voltage deviations within tolerance bands and only acting when thresholds are exceeded, the system maintains adequate voltage stability while significantly reducing the frequency of tap changes and extending equipment life
Solution Approach 2:
The patent implements beforehand cushioning by establishing tolerance bands around voltage set points and implementing delay mechanisms before executing tap changes. This cushioning approach prevents unnecessary frequent adjustments by allowing small deviations and requiring sustained conditions before triggering changes, thereby protecting the tap changer while maintaining voltage stability
3Measurement precision
If more data is collected from the electrical network, then the precision of the result is improved, but the device complexity and data processing requirements worsen
Solution Approach 1:
The patent implements multi-functionality by using a single data collection and processing system that handles multiple tasks: collecting network data, analyzing load conditions, determining optimal voltage set points, and controlling the tap changer. This universal approach improves precision through comprehensive data utilization while avoiding the complexity of multiple separate systems
Solution Approach 2:
The patent merges data collection, analysis, and control functions into an integrated system. By combining these functions rather than separating them into independent systems, the patent achieves high precision through comprehensive data processing while managing complexity through integration and centralized control
Data Source
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AI summary
The method of the invention dynamically determines the optimal voltage set point for the on-load electrical tap changer (4) and the corresponding parameters of the automatic voltage regulator (3) so that they are in correspondence with each other, and generally comprises the following steps: - Obtaining (5) at least one variable and/or at least one parameter of an electrical network (6) comprising a high voltage side (7) and a low voltage side (8), - Generating (11) an electrical network model (6) and launching (12) a load flow or state estimate, - Calculating or estimating (13) voltage drops and load of electrical network lines (6), - Determining (14) the optimal voltage set point, and - Setting (10) the control policy followed by the automatic voltage regulator (3) that controls the on-load tap changer (4).