Microgrid Hardware Stack

interconnection · distribution · sources · loads

Every microgrid is built from the same layers of distribution hardware. The switch at the point of common coupling is what makes it a microgrid.

Microgrid hardware from utility to loads, as five stacked layers: interconnection (utility transformer, meter, point of common coupling switch); distribution (MV/LV transformer, main bus, switchboard); energy sources (PV inverters, battery power conversion systems, gensets); loads (critical, priority and sheddable, with automatic transfer switches); and protection (relays, breakers, grounding). A controller with SCADA, EMS and HMI spans every layer. MICROGRID HARDWARE, UTILITY TO LOADS Interconnectionutility transformer, meter, PCC switch DistributionMV/LV transformer, main bus, switchboard Energy sourcesPV inverters, battery PCS, gensets Loadscritical, priority, sheddable; ATS Protectionrelays, breakers, grounding Controller SCADA, EMS HMI spans all layers
Interconnection
IEEE 1547, UL 1741 SB
Battery safety
UL 9540, NFPA 855
Controller
IEEE 2030.7
Typical build
6-18 months
Hub
Energy

Finding

A microgrid's hardware is ordinary distribution gear plus one decisive addition: a controllable switch at the point of common coupling that lets the site island

Transformers, switchgear, inverters and batteries are the same equipment used across the grid. What makes a microgrid is the point of common coupling (PCC): a breaker and relay package that opens on a utility fault, lets on-site sources carry the load, and resynchronizes when the grid returns.

Islanding changes protection. A synchronous generator can supply 5-10 times rated current into a fault; an inverter typically supplies only 1.1-1.5 times, so overcurrent relays set for the grid may never trip in island mode. Inverter-heavy microgrids need protection settings that switch with the operating mode, or differential and voltage-based schemes from SEL, ABB, Siemens or GE Vernova.

Suppliers: Schneider Electric, Eaton, Siemens, ABB and Hitachi Energy for switchgear and transformers; SEL for relays; Huawei, Sungrow, SMA and Dynapower for inverters and battery PCS; Chint, TBEA, XD Electric and NARI for Chinese distribution and protection gear. Most microgrids are deployed in 6-18 months, faster than a utility upgrade, but long-lead transformers and switchgear can set the schedule (bottlenecks).

Components

Hardware components

Microgrid hardware components
ComponentRoleNotes
TransformerSteps utility or internal voltage up or downLongest lead item; grain-oriented steel cores
Switchgear and PCC breakerSwitches, isolates and protects circuits; opens to islandSmart units automate islanding and reclosing
Protection relaysDetect faults and trip breakersNeed settings for both grid-tied and islanded fault levels
Inverters and PCSConvert DC to AC and back for PV and batteriesGrid-forming units can set voltage and frequency
Battery storageStores and releases energy; stabilizes the islandLFP dominates; needs UL 9540A fire testing
BMSManages cell charge, temperature and healthReports state of charge to the controller
Busbars and panelboardsDistribute power inside the facilityAC, DC or hybrid buses
Automatic transfer switchesMove critical loads between sourcesSeparate critical from sheddable circuits
Microgrid controller / PLCControl logic for dispatch and transitionsInterfaces with SCADA, EMS and DERMS
GroundingFault protection and personnel safetyMust work in both modes; critical at hospitals and data centers

Emerging

Emerging hardware

Emerging microgrid hardware
TechnologyWhat it changesStatus
Solid-state transformerReplaces the iron-core transformer and adds power conditioning; native DC outputPilots at LV and MV; startups include Heron Power, Amperesand, DG Matrix
DC distribution busRemoves conversion stages between PV, batteries, chargers and DC loadsGrowing in depots and 800 V DC data center designs
Hybrid AC/DC panelsLets legacy AC loads and DC-native equipment share a siteTransitional designs
SF6-free switchgearReplaces SF6 gas insulation with vacuum or clean-air designsEU F-gas rules phase out SF6 in new medium-voltage gear
Power quality conditioningFilters harmonics and sags for sensitive loadsStandard at fabs, labs and AI data centers

Codes

Standards and permits

Deployment is usually faster than a utility upgrade, but each layer has its own code.

Microgrid standards and permits
RequirementStandardNotes
InterconnectionIEEE 1547-2018, UL 1741 SBPlus each utility's own rules
Microgrid controllerIEEE 2030.7 (spec), IEEE 2030.8 (testing)Defines dispatch and islanding transitions
Battery safetyUL 9540, UL 9540A, NFPA 855Spacing, fire suppression, local fire marshal review
Electrical codeNEC Articles 705, 706, 710Interconnected sources, energy storage, stand-alone systems
Air permitsEPA and state rulesLimits run hours for diesel and gas gensets
CybersecurityIEC 62443; NERC CIP where applicableScrutiny rises for critical infrastructure

Sources

Sources and scope

Scope
Microgrid Hardware Stack
Sources
IEEE 1547, 2030.7 and 2030.8; UL 1741 and 9540; NFPA 855; NEC; EU F-gas Regulation
Updated
October 2026