Grid Edge Voltage Regulators for Frequency Stability
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Solution Overview
Problem
Existing power distribution systems face challenges in maintaining frequency stability during transient line frequency variations, particularly in low-inertia islanded microgrids, where traditional methods like under-frequency load shedding require tripping loads, which is undesirable.
Innovation Solution
The implementation of distributed power-electronics-based devices, such as dynamic voltage restorers (DVRs) and series/shunt compensators, at the grid edge to dynamically adjust voltage setpoints in response to line frequency variations, thereby stabilizing the grid frequency without load shedding, using advanced control strategies and machine learning technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If under-frequency load shedding is used to regulate grid frequency during emergencies, then frequency stability is improved, but load continuity deteriorates due to tripping of loads
Solution Approach 1:
The patent replaces the mechanical load tripping mechanism with an electrical control system. Distributed power electronics devices (voltage regulators, compensators) use electrical signals to adjust voltage setpoints in response to frequency deviations, thereby regulating frequency without mechanically tripping loads. This substitution eliminates the harmful mechanical action of load shedding while achieving the same frequency stabilization goal.
Solution Approach 2:
The patent introduces distributed power electronics devices as intermediary components between the grid frequency disturbance and the loads. These devices (voltage regulators, series/shunt compensators) act as mediators that sense frequency variations and respond by adjusting voltage setpoints, thereby indirectly regulating frequency without directly tripping loads. The intermediary devices absorb the control action that would otherwise require load tripping.
2Reliability
If distributed power electronics devices adjust voltage setpoints in response to frequency variations, then frequency stability is improved, but device complexity increases
Solution Approach 1:
The patent makes existing distributed power electronics devices multi-functional. Voltage regulators and compensators that were traditionally designed solely for voltage regulation are enhanced to also perform frequency stabilization by adding frequency-sensing capabilities and adaptive setpoint adjustment. This universality allows a single device to serve dual purposes, avoiding the need for separate frequency control devices and reducing overall system complexity.
Solution Approach 2:
The patent merges the frequency control function with the existing voltage regulation function in distributed power electronics devices. By combining these two control functions into a unified system where the same devices perform both voltage and frequency stabilization, the patent reduces the total number of components and control systems needed, thereby managing complexity while achieving dual objectives.
Data Source
AI summary
Methods include, in response to a line frequency variation of a power grid, adjusting a voltage setpoint of a voltage regulator coupled to the power grid at a grid edge to maintain a voltage at the grid edge, wherein the adjusting the regulated voltage setpoint is configured to reduce the line frequency variation to stabilize the line frequency of the power grid. Apparatus include a voltage regulator configured to couple to a power grid at a grid edge and to maintain a voltage at the grid edge, wherein the voltage regulator is further configured to adjust a voltage setpoint of a voltage regulator in response to a line frequency variation of the power grid to reduce the line frequency variation and stabilize the line frequency of the power grid.