DC Substation Energy Flow Detection via AC Meter Calculation
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Solution Overview
Problem
Current DC substations face challenges in accurately measuring and controlling energy flow due to measurement errors and the lack of certified DC meters, leading to complex and difficult-to-control systems that do not meet legal requirements.
Innovation Solution
A DC substation design with a simple architecture, featuring an AC electricity meter, transformer, bidirectional AC/DC converter, and branching circuit with determination devices, which measure and control energy flow using synchronized sampling frequencies and a controller to calculate energy consumption and production, accounting for electrical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If certified DC meters are used for energy measurement, then measurement precision would be improved, but device complexity increases and such meters are not available on the market
Solution Approach 1:
The patent introduces an intermediary calculation method that uses multiple AC meters to measure different parameters (active power, reactive power, current) and combines these measurements through a calculation unit to derive DC energy values. This mediator approach avoids the need for unavailable certified DC meters while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces the physical DC metering system with an equivalent calculation-based system. Instead of using a physical DC energy meter (which doesn't exist in certified form), the system substitutes a combination of AC meters and a calculation unit that mathematically derives DC energy consumption from AC side measurements and power conversion relationships.
2Measurement precision
If multiple measurement devices are used to control energy flow, then measurement precision is improved, but device complexity and difficulty of control increase
Solution Approach 1:
The patent merges multiple measurement functions into a unified calculation framework. Instead of using separate measurement devices for different parameters, the system combines AC power measurements, reactive power measurements, and current measurements into a single integrated calculation process that outputs comprehensive DC energy flow data.
Solution Approach 2:
The calculation unit continuously receives feedback from multiple measurement devices (AC power meter, reactive power meter, current meter) and dynamically adjusts energy flow control decisions based on real-time calculations of DC energy consumption, enabling precise control while maintaining ease of operation through automated feedback loops.
3Reliability
If certified measurement devices are used to meet legal requirements, then reliability is improved, but such devices are not available for DC applications
Solution Approach 1:
The patent changes the measurement parameters from direct DC energy measurement to AC-side parameter measurements (active power, reactive power, current) that can be accurately measured with available certified AC meters. By transforming the measurement approach to use available AC measurement parameters and deriving DC energy through calculation, the system achieves both reliability and adaptability.
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
The solution enables reliable energy flow detection and control, facilitating accurate billing and financial transactions while simplifying the system's architecture and compliance with legal standards without the need for certified DC meters.
Implementation Method 1
a transformer (42) and AC/DC converter (44)
Implementation Method 2
AC/DC converter (44), having a DC terminal (46)
Data Source
AI summary
The present invention relates to a DC substation (10) comprising a first terminal (20) adapted to connect the DC substation (10) to an AC electrical power grid (12); a plurality of second terminals (22, 24, 26) adapted to provide or receive DC current to or from a respective load (14, 16, 18); a current supply chain (30) comprising an AC electricity meter (40), an AC/DC converter (44), and a branching circuit (53), wherein the AC electricity meter (40) is configured for measuring an electrical energy, and the branching circuit (53) providing respectively one branch (48, 50, 52) for each second terminal (22, 24, 26); a plurality of determination devices (54, 56, 58, 60) for determining a direct current, a voltage meter (66) and a controller (68) adapted to determine the respective electrical energy consumption or production.