Multi-Port AC Interconnection for Feeder Power Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional AC power grids face challenges with feeder line congestion, load imbalance, and the integration of intermittent renewable energy sources like wind and solar due to limited control capabilities, leading to inefficiencies and high costs in infrastructure upgrades.
Innovation Solution
A multi-port Flexible Alternative Current Interconnector (FACI) system with a Static Synchronous Compensator (STATCOM) and a multi-port flexible interconnection module, utilizing medium-voltage-level voltage source inverters and single-phase transformers to achieve active power flow control and reactive power compensation, with a control method involving line flow, static synchronous compensator, and common bus voltage balance control loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If back-to-back voltage source inverters are used for FACI topology, then bidirectional power flow operation and decoupling control of active and reactive power can be achieved, but the system suffers from high cost, high loss, large size, and high failure rate
Solution Approach 1:
The patent divides the single-phase inverter into multiple full-bridge modules connected in series, where each module handles a portion of the total voltage. This segmentation allows the system to achieve high voltage output without requiring a single large, complex inverter, thereby reducing device complexity and failure rate while maintaining bidirectional power flow capability
Solution Approach 2:
The patent implements a hierarchical control structure with outer loops for active and reactive power control, and inner loops for current control. This nested control architecture enables decoupling control of active and reactive power while organizing the control system in a manageable, modular fashion that reduces overall system complexity
2Ease of operation
If traditional regulation methods such as on-load tap changers or feeder line switch actions are used, then voltage regulation and load balancing can be achieved, but the response speed is slow and accuracy is insufficient
Solution Approach 1:
The patent replaces mechanical regulation devices (on-load tap changers and contact switches) with a power electronics-based FACI system using IGBT modules and PWM control. This substitution eliminates mechanical wear and slow response, achieving rapid response speed and high control accuracy for voltage regulation and load balancing
Solution Approach 2:
The patent employs pulse width modulation (PWM) control with high-frequency switching of IGBT modules to regulate power flow. This periodic switching action enables precise control of active and reactive power with fast response, far exceeding the capabilities of traditional mechanical regulation methods
3Reliability
If the AC power grid lacks control ability, then system stability and reliability are maintained, but feeder line congestion and load imbalance cannot be effectively addressed
Solution Approach 1:
The patent implements dual closed-loop control systems: an outer loop that monitors active and reactive power demands and an inner loop that controls converter currents. This feedback mechanism allows the FACI to dynamically adjust power flow while maintaining grid stability, effectively addressing feeder line congestion and load imbalance without compromising system reliability
Solution Approach 2:
The patent transforms the static AC grid connection into a dynamic, controllable interface using power electronics. The FACI system can rapidly adjust its impedance characteristics and power flow in real-time based on grid conditions, providing adaptability for power flow management while maintaining stability through coordinated 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
The system enhances power grid stability and efficiency by enabling rapid, accurate control of active and reactive power flow, reducing costs and infrastructure needs, and optimizing power distribution.
Implementation Method 1
medium-voltage-level voltage source inverters
Implementation Method 2
single-phase transformers
Data Source
AI summary
The invention discloses a multi-port flexible AC interconnection device with active power flow control capability for an AC power grid, including a static synchronous compensator and a multi-port flexible interconnection module connected in series. The multi-port flexible interconnection module includes multiple voltage-source single-phase inverters sharing a DC bus, and each port is connected to a different AC power grid feeder line. By adjusting the amplitude and phase of the AC output voltage of the single-phase inverters connected in series on the feeder line, flexible interaction of active power between the feeder lines is realized, and decoupled control of active and reactive power on the feeder lines is achieved. By introducing the multi-port flexible interconnection module, the invention provides multiple controllable AC ports connected to multiple feeder lines, realizing flexible interconnection between the feeder lines, i.e., flexible interaction of active power between the feeder lines and achieving active control of power flow between the feeder lines, which can realize a flexible AC power grid with multi-port interconnection while providing corresponding reactive power to each feeder line.