STATCOM Real Power Transfer for Multiphase Grid Voltage Balancing
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Solution Overview
Problem
Voltage unbalance is a persistent issue in long low-voltage distribution networks, primarily caused by unbalanced loads and power generation from single-phase connections, which existing technologies struggle to effectively address without using energy storage systems.
Innovation Solution
The system employs a static synchronous compensator (STATCOM) to transfer active power between individual phases of a multi-phase grid system, calculating average voltage values and determining voltage differences to produce real current references that balance voltages across phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If energy storage systems (e.g., batteries) are used to balance voltage, then voltage unbalance can be effectively addressed, but system complexity and cost increase
Solution Approach 1:
The patent extracts the energy storage component from the voltage balancing system, achieving voltage balance through real power transfer between phases using only the STATCOM. This eliminates the need for batteries or other energy storage devices, resolving the contradiction by removing the complex component while maintaining the desired voltage balance function.
Solution Approach 2:
The STATCOM acts as an intermediary device that enables real power transfer between unbalanced phases without requiring energy storage. By controlling the STATCOM to inject or absorb real power on specific phases, the system achieves voltage balancing through power redistribution rather than energy storage, thereby reducing system complexity.
2Reliability
If real power transfer between phases is implemented using STATCOM, then voltage unbalance is reduced without energy storage, but control complexity increases
Solution Approach 1:
The patent implements a feedback control mechanism where the STATCOM controller continuously monitors phase voltages and adjusts real power transfer accordingly. The controller calculates the voltage unbalance and modulates the STATCOM to inject or absorb real power on specific phases to reduce the unbalance, creating a closed-loop system that automatically maintains voltage balance without requiring complex open-loop control strategies.
3Reliability
If conventional load balancing methods are used by connecting phases consecutively to houses, then some voltage unbalance is mitigated, but distribution lines remain unbalanced most of the time
Solution Approach 1:
The patent replaces the mechanical/conventional approach of consecutively connecting phases to houses with an electronic control system. Instead of physically reconfiguring the distribution network, the STATCOM electronically redistributes real power between phases through controlled injection and absorption, achieving superior voltage balancing effectiveness without the limitations of conventional mechanical switching methods.
Data Source
AI summary
Disclosed is a method for voltage balancing. The method comprises (a) calculating an average voltage value from voltages of first and second phases of the multiphase grid system. The method also comprises (b) determining at least (1) a first voltage difference and (2) a second voltage difference. The method also comprises (c) producing at least (1) a first real current reference based on the first voltage difference and (2) a second real current reference based on the second voltage difference. The method also comprises (d) generating at least (1) a first alternating current (AC) voltage reference and (2) a second AC voltage reference. The method also comprises (e) modulating the first AC voltage reference and the second AC voltage reference to generate an input for a voltage source converter. The method also comprises (f) using at least the modulated input to provide real current to the multiphase grid system.