Microgrid Voltage Control Using Central and Secondary Controllers
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Solution Overview
Problem
Existing voltage control solutions for microgrids with decentralized energy sources fail to maintain grid voltage within contractual ranges during high active power flows, leading to overvoltage issues and inadequate reactive power distribution.
Innovation Solution
A control device with a central automatic controller and secondary controllers for each generation/storage unit, adjusting voltage settings based on total active and reactive power measurements to maintain a reference voltage across the microgrid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional voltage control solutions are used in microgrids with decentralized producers, then the system structure is simple, but voltage deviations occur during high active power injections leading to overvoltage issues
Solution Approach 1:
The control system is segmented into a central automatic controller that computes offset voltages based on total active and reactive power, and secondary automatic controllers at each generation/storage unit that apply these offsets. This segmentation allows distributed voltage control while maintaining coordinated management, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The central controller pre-computes offset voltages based on measured total active power and reactive power before voltage deviations occur. These offset voltages are transmitted to secondary controllers in advance, enabling proactive voltage control that prevents overvoltage conditions rather than reacting to them after they occur.
2Stability of the object's composition
If offset voltage control is implemented to maintain voltage reference, then voltage stability improves, but control algorithm complexity increases
Solution Approach 1:
The system implements feedback by measuring total active power and reactive power at the common connection terminal, using these measurements to compute appropriate offset voltages, and applying these offsets to maintain the voltage reference. This closed-loop feedback mechanism ensures voltage stability while keeping the control algorithm manageable through systematic use of measured quantities.
Solution Approach 2:
The control algorithm manages complexity by changing parameters systematically - it computes offset voltages based on measured active power and reactive power parameters, then applies these voltage offsets at secondary controllers. This parameter-based approach transforms a complex multi-variable control problem into a series of manageable parameter adjustments.
Data Source
AI summary
The present invention concerns a device for controlling a plant with an electricity generation and/or electricity storage unit and a connection terminal intended to be connected to a microgrid, comprising an automatic controller (100) configured to compute a setpoint voltage Uref(i) of each unit, members (1, 2, 3, 4i, 5) for measuring or determining a total active power Pcentrale, a voltage URmes of the terminal, of a voltage reference UcentraleRef according to a function f depending at least on the total active power Pcentrale, of a first individual reactive power Qmes(i) of each unit, a first voltage corrector (5), having a second prescribed transfer function corr, the automatic controller being configured to compute UcentraleRef=f(Pcentrale), and Uoffset=corr(UcentraleRef−URmes) and Uref(i)=Uoffset(i)−KUQ(i)−Qmes(i).