Microgrid Autosynchronizing via Recloser Control Inputs

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Solution Overview

Problem

Distributed energy resources (DERs) in microgrids operate asynchronously with area electric power systems when islanded, leading to voltage, phase, and frequency differences that hinder reconnection after a fault, necessitating a method to synchronize power generation.

Innovation Solution

A recloser control system that communicates synchronization signals by measuring electrical characteristics of both the microgrid and area EPS, using potential transformers to detect differences and send synchronization signals to DER controllers or microgrid controllers to align voltage, phase, and frequency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If DERs operate independently in islanded microgrids, then microgrid autonomy and reliability during faults are improved, but voltage, phase, and frequency synchronization with area EPS deteriorates

Engineering Contradiction:

Improvemicrogrid autonomy during faultsVSAvoidsynchronization precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The recloser control system continuously monitors voltage, phase, and frequency parameters from both the microgrid and area EPS through potential transformers. This feedback mechanism enables real-time detection of synchronization parameters and automatic adjustment of DER operations to maintain precise synchronization before recloser reclosing, resolving the contradiction between autonomous operation and synchronization precision.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary synchronization measurements and calculations before the recloser recloses. By determining synchronization parameters in advance and adjusting DER operations beforehand, the system ensures that voltage, phase, and frequency are aligned before reconnection, thus maintaining both autonomy during faults and precision at reclosing moment.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If recloser recloses immediately after fault clearance, then power supply continuity is improved, but unsynchronized reconnection causing equipment damage risks increases

Engineering Contradiction:

Improvepower supply continuityVSAvoidequipment safety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary synchronization checks and parameter measurements before allowing recloser reclosing. By calculating required DER adjustments in advance and verifying synchronization conditions are met, the system enables rapid reclosing while ensuring equipment safety through pre-validated synchronization status.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The recloser control system uses real-time feedback from potential transformers to continuously monitor whether synchronization parameters are within acceptable ranges. This feedback gate controls the reclosing process, allowing rapid reclosure only when synchronization conditions are confirmed, thus balancing productivity and reliability.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If synchronization measurements are performed continuously, then synchronization accuracy is improved, but communication bandwidth consumption and system complexity increase

Engineering Contradiction:

Improvesynchronization measurement accuracyVSAvoidcommunication system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs synchronization measurements periodically at critical moments (fault detection, before reclosing) rather than continuously. This periodic measurement approach maintains sufficient synchronization accuracy for safe reclosing while significantly reducing communication bandwidth consumption and system complexity compared to continuous monitoring.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The recloser control system performs self-measurement of synchronization parameters using its own potential transformers and internal processing capabilities. This self-service approach eliminates the need for complex external communication infrastructure, achieving measurement precision without proportionally increasing system complexity.

Inventive Principle:

Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables synchronized reconnection of microgrids to area EPS by adjusting DER operations, ensuring stable power supply and efficient reintegration after transient events.

Implementation Method 1

using potential transformers to detect differences and send synchronization signals

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS11239659B2Microgrid autosynchronizing using remote recloser inputs and outputs

Publication Date: 2022.02.01 SCHWEITZER ENGINEERING LABORATORIES INC

AI summary

The present disclosure relates to a recloser control that provides autosynchronization of a microgrid to an area electric power system (EPS). For example, a recloser control may include an output connector that is communicatively coupled to a recloser at a point of common coupling (PCC) between the area EPS and the microgrid. The recloser control may include a processor that acquires a first set of measurements indicating electrical characteristics of the area EPS and acquires a second set of measurements indicating electrical characteristics of the microgrid. The recloser control may send synchronization signals to a microgrid controller to synchronize the microgrid controller based on the first set of measurements and the second set of measurements.