Distribution Feeder Integral Voltage Control for DER Limit Violations
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Solution Overview
Problem
The integration of distributed energy resources (DERs) in power distribution systems poses challenges in voltage control, as high generation from sources like PV can lead to overvoltage, while high loads from EV charging can result in undervoltage, requiring active management to maintain voltage within defined limits.
Innovation Solution
The methodology employs an integral voltage control method that uses feedback from measured or estimated voltages along the feeder to generate a control action, distributed among controllable DERs, allowing them to absorb or inject reactive power and adjust active power to maintain voltage within limits, without requiring a power system model or additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DERs are integrated into the distribution system to increase renewable energy penetration, then energy sustainability is improved, but voltage control stability deteriorates due to voltage fluctuations from high generation and high load conditions
Solution Approach 1:
The patent implements a feedback control mechanism where voltage measurements from multiple locations along the feeder are continuously monitored, compared against defined voltage limits, and used to generate corrective control actions. The error between measured voltage and defined limit is input to an integrator that generates control actions to counteract voltage deviations, creating a closed-loop feedback system that maintains voltage stability despite DER fluctuations
Solution Approach 2:
The control system utilizes the existing voltage regulating capabilities of DER inverters themselves to maintain voltage stability. The controllable DERs absorb or inject reactive power based on the control signals generated by the integral controller, allowing the DERs to self-regulate and contribute to voltage control without requiring external voltage regulation equipment
2Manufacturing precision
If optimization-based voltage control is implemented using power system models, then voltage control precision is improved, but system complexity increases due to model maintenance and computational requirements
Solution Approach 1:
The system uses readily available operational data (voltage measurements from PMUs or estimated voltages) without requiring complex power system models. The integral controller automatically adapts to changing system conditions through its inherent integration mechanism, eliminating the need for model updating and complex computations while maintaining effective voltage control
Solution Approach 2:
The patent changes the control approach from model-based optimization to integral control based on voltage error. By using the integrator to accumulate voltage errors over time and generate control actions, the system achieves adaptive voltage control without requiring complex system parameters or models, simplifying the control architecture
3Stability of the object's composition
If reactive power compensation is used to control voltage, then voltage stability is improved, but energy loss increases due to reactive power flow
Solution Approach 1:
The control system distributes reactive power compensation locally among controllable DERs based on their individual capabilities and proximity to voltage violations. Each DER responds to the control signal according to its own characteristics, providing localized voltage support that minimizes unnecessary reactive power flow and associated energy losses
Data Source
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AI summary
A method for controlling voltage in a feeder of a distribution system having a plurality of DERs includes executing a feedback control using an integral controller. A voltage signal is generated using measured or estimated voltages at multiple locations along the feeder. An error is determined between the voltage signal and a defined voltage limit. The error is input to a controller including an integrator to generate a control action to counteract the error. The control action is distributed among at least some controllable DERs, from the plurality of DERs, that are capable of responding to the control action by generating actuation signals for absorbing reactive power from or injecting reactive power into the feeder, and/or for reducing active power or increasing active power in the feeder. The control action continues to increase until the voltage signal reaches the defined voltage limit, to thereby control voltage in the feeder.