DC Link Power Balancing for AC Distribution Networks
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Solution Overview
Problem
Current electrical supply networks face challenges in power balancing between rural and urban areas due to high short-circuit power and inadequate control of power flows in AC distribution grids, requiring reinforcement of high-voltage grids, which is costly and inefficient.
Innovation Solution
Implementing a direct DC voltage connection between medium-voltage networks using a power converter to actively control power flows and compensate for different consumption and load behaviors, allowing for decentralized and regenerative power distribution without additional load on the transmission network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If AC distribution networks are used to transmit power from rural generation areas to urban consumption areas, then power transmission is achieved, but short-circuit power becomes excessively high and power flow control becomes insufficient
Solution Approach 1:
The patent introduces a DC link as an intermediary between rural and urban distribution networks. This DC connection acts as a mediator that enables power transmission while isolating the harmful short-circuit power effects that would otherwise propagate through the AC network. The DC link converts AC to DC and back to AC, breaking the direct AC connection that causes excessive short-circuit power.
Solution Approach 2:
The patent changes the electrical parameter domain from AC to DC for the interconnection between distribution networks. By converting the connection type from AC to DC, the system fundamentally alters the electrical characteristics, eliminating the short-circuit power problems inherent in AC networks while maintaining power transmission capability.
2Ease of operation
If AC distribution networks are reinforced to balance load between rural and urban areas, then power balancing is improved, but device complexity and construction cost increase
Solution Approach 1:
Instead of reinforcing the existing AC grid infrastructure, the patent introduces a DC link as an intermediary system that handles power balancing independently. This mediator approach allows load balancing between rural and urban areas without modifying or reinforcing the complex AC distribution networks, thereby reducing device complexity and construction costs.
3Ease of operation
If direct DC connection is implemented between distribution networks, then power flow control is improved and short-circuit power is reduced, but device complexity increases due to power converters
Solution Approach 1:
The patent positions power converters as intermediary devices that enable controlled power flow between AC distribution networks through a DC link. While the converters add some complexity, they provide precise control capabilities that far outweigh the added complexity, enabling independent power flow management without affecting the existing AC networks.
4Power
If DC link is used for power transmission between distribution networks, then transmission network burden is reduced, but measurement and control complexity increases
Solution Approach 1:
The patent implements measurement devices and control systems that continuously monitor power flow through the DC link and provide feedback for automatic adjustment. This feedback mechanism simplifies the overall system by enabling autonomous power flow management, reducing the burden on the transmission network while maintaining manageable measurement and control complexity through automated closed-loop control.
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
Enables efficient power balancing between distribution networks, optimizing neutral point treatment and reducing the need for high-voltage grid reinforcement, while allowing for direct integration of renewable energy sources and reducing the risk of ground faults.
Implementation Method 1
A power converter is especially suitable for this purpose. A power converter is also commonly understood as an electrical valve. The power converter can be configured so that both the current flow direction and the transmitted power are adjustable.
Data Source
AI summary
An electrical supply network comprising a distribution network and at least two strings (14a, 14b) of an AC medium-voltage network, wherein the strings of the AC medium-voltage network are each connected to the distribution network (8a, 8b) via a transformer (12a, 12b). Power equalization is particularly possible if a direct DC connection (16) is formed between the strings of the AC medium-voltage network (14a, 14b).