Parallel Transformer Control via Data Bus
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Solution Overview
Problem
Existing methods for parallel control of tapped transformers require additional devices and complex cabling, making them inefficient and prone to errors, especially when transformers are removed from operation, as they necessitate changes in voltage regulator settings.
Innovation Solution
A method that mathematically derives all measured values from current or voltage transformers, allowing for simplified converter circuits and eliminating the need for additional devices and current-carrying cross-connections, using a common data bus for information exchange between voltage regulators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate parallel control devices are used for each transformer, then circulating reactive current can be minimized, but device complexity and cabling requirements increase
Solution Approach 1:
The patent merges the functions of separate parallel control devices into a single centralized control device that receives measurements from all transformers and calculates control signals for all tap changers. This eliminates the need for individual control devices at each transformer, reducing device complexity while maintaining the ability to minimize circulating reactive currents through centralized coordination.
Solution Approach 2:
The single control device performs multiple functions: it receives measurements from all transformers, calculates circulating currents, determines optimal tap positions for all transformers, and sends control signals to all tap changers. This multi-functional approach replaces multiple specialized control devices, reducing overall system complexity.
2Reliability
If current-carrying cross-connections between instrument transformers are implemented, then parallel control can be achieved, but wiring complexity increases
Solution Approach 1:
The patent introduces a communication network as an intermediary between instrument transformers and the control device. Instead of direct current-carrying cross-connections, measurements are transmitted through this communication intermediary, which simplifies wiring while maintaining parallel control capability.
Solution Approach 2:
The patent replaces the mechanical/electrical current-carrying cross-connections with an electronic communication system. The control device receives digital or electrical signals through the communication network rather than requiring direct current connections between transformers, significantly reducing wiring complexity.
3Adaptability or versatility
If transformers are removed from parallel operation, then system flexibility is improved, but changes in voltage regulator settings are required
Solution Approach 1:
The control device automatically detects when transformers are added or removed from parallel operation and autonomously recalculates control signals and voltage regulator settings. This self-adjusting capability eliminates the need for manual intervention, maintaining ease of operation while improving system flexibility.
Solution Approach 2:
The control device continuously receives feedback from instrument transformers about their operating status and automatically adjusts control signals and voltage regulator settings in response to changes in the parallel configuration. This closed-loop feedback mechanism enables automatic adaptation to transformer additions or removals without requiring manual setting changes.
Data Source
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AI summary
The invention relates to a method for parallel control of transformers having step switches. All voltage controllers are thereby connected to each other by means of a common data bus. An active current and reactive current are first determined for each step transformer connected in parallel, then the phase angle of an arising total current is determined from the sum thereof, and each circuit reactive current results in turn therefrom, from which ultimately the signed control deviation of each voltage regulator is derived separately for each step switch.