Resiliency Controller for Microgrid Voltage Regulation

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Solution Overview

Problem

The increasing penetration of renewable energy sources, particularly solar photovoltaic (PV) systems, leads to voltage rise challenges due to reverse power flows and high variability, disrupting traditional distribution system operations and requiring disruptive solutions like restricting PV output or tripping relays.

Innovation Solution

A computer-implemented method and system using a resiliency controller with a voltage control module, reactive power estimator, and dynamic droop control unit to collect measurement data, calculate reactive power needs, and distribute reactive power among distributed generators in a microgrid, integrating PV systems with energy storage to adaptively manage voltage fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If PV generation is increased to maximize renewable energy usage, then renewable energy penetration is improved, but voltage rise and reverse power flow problems worsen

Engineering Contradiction:

Improverenewable energy usageVSAvoidvoltage rise

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the operating parameters of distributed generators by dynamically adjusting reactive power output based on voltage measurements. The controller modifies the reactive power setpoint according to the relationship between voltage deviation and reactive power injection/absorption, enabling the system to accommodate higher PV penetration while maintaining voltage within acceptable limits.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements a feedback control mechanism where voltage measurements from PMUs are continuously monitored and fed back to the resiliency controller. The controller processes this feedback information and adjusts reactive power output of distributed generators in real-time, creating a closed-loop control system that responds to voltage changes caused by varying PV generation and load conditions.

Inventive Principle:

Principle #23Feedback

2Reliability

If traditional over-voltage/under-voltage relays are used to protect against voltage issues, then voltage protection is improved, but PV output is disrupted and renewable energy usage is reduced

Engineering Contradiction:

Improvevoltage protectionVSAvoidPV output

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent introduces a resiliency controller as an intermediary device between the voltage monitoring system and the distributed generators. Instead of using traditional relays that directly trip PV output, the controller acts as a mediator that processes voltage information and adjusts reactive power output to maintain voltage within acceptable ranges, thereby protecting the system while keeping PV generation continuous.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent enables the power system to self-regulate voltage conditions through automatic reactive power adjustment by distributed generators. The system monitors its own voltage status and autonomously modifies generator output to correct voltage deviations, eliminating the need for disruptive relay tripping and manual intervention.

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If PV generation is restricted to prevent voltage rise, then voltage stability is improved, but renewable energy usage is reduced

Engineering Contradiction:

Improvevoltage stabilityVSAvoidrenewable energy usage

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent transforms the static, fixed reactive power output of distributed generators into a dynamic, adjustable parameter. The resiliency controller continuously modifies the reactive power setpoint based on real-time voltage conditions, allowing the system to adapt to changing PV generation and load patterns while maintaining voltage stability and maximizing renewable energy utilization.

Inventive Principle:

Principle #15Dynamics

4Ease of operation

If reactive power compensation equipment is added to regulate voltage, then voltage control capability is improved, but system complexity and cost increase

Engineering Contradiction:

Improvevoltage control capabilityVSAvoidsystem complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent enables distributed generators to perform multiple functions: active power generation from PV panels and reactive power adjustment for voltage control. By making the generators multi-functional, the system eliminates the need for separate reactive power compensation equipment such as capacitor banks or static VAR compensators, thereby reducing system complexity and cost while maintaining voltage control capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10333346B2Resiliency controller for voltage regulation in microgrids

Publication Date: 2019.06.25 NEC CORP

AI summary

A computer-implemented method for controlling voltage fluctuations of a microgrid including a plurality of distributed generators (DGs) is presented. The computer-implemented method includes collecting, by a resiliency controller including at least a voltage control module, measurement data from the microgrid, using, by a reactive power estimator, reactive power estimations to calculate an amount of reactive power for each of the DGs, and using a dynamic droop control unit to distribute the reactive power to each of the DGs of the microgrid.