Microgrid energy management
A Gateway brings the PCC, sources, storage, priority loads and controller states into one time-aligned record while the approved microgrid controller retains control authority.
- Measure
- PCC flow and breaker state, source output, battery reserve, retained loads, operating mode and active constraints
- Calculate
- Transitions, load shedding, reserve use, dispatch response, stale data and the energy balance for each operating state
- Sensors
- ZEM-65, for suitable low-voltage owner measurements; use approved plant meters for MV and protection boundaries Wireless 3-Phase Electricity Monitor datasheet
- On site
- ZGW-20 Gateway, keeps the operational evidence in Edge without becoming the microgrid controller Gateway datasheet
Define the electrical boundary and every operating state
Start with the single-line diagram, the PCC breaker and the circuits that remain energised in an island. Name the controller, protection, synchronising, BMS, generator and load-shedding authorities for grid-connected, transition, islanded, black-start and reconnection states. Monitoring should explain their actions without creating another command path.
Hardware for microgrid controller monitoring
Use independent owner measurements where they add evidence, and acquire approved equipment states through documented read-only interfaces. Protection and controller measurements stay in their engineered systems.
Combines owner measurements and plant states in Edge for local history, checks, alerts and onward data
1 per site up to 250 wireless devices
Use only within the product's rated installation boundary
Independent measurement of a suitable LV PCC, source feeder, retained-load group or auxiliary supply
1 per required LV boundary three-phase, 3 or 4 wire
- Choose the CT rating for a suitable low-voltage circuit: 120 A split-core, or 300 A, 1 kA and 3 kA Rogowski coils
Class 0.5S to IEC 62053-22 with its CTs, 110 to 480 V line to line, CAT III at 480 V
Only where the equipment owner permits a separate read-only client
Read-only acquisition of documented controller, inverter, BESS, generator, meter and breaker-status registers
1 per available bus up to 30 registers
Modbus RTU over RS-485; use only an approved single-master connection and exact register map
Record the boundary, resources and operating state
Keep raw values, quality and source timestamps. A site balance explains energy over aligned intervals; it does not replace the faster voltage, frequency, phase-angle and protection signals used to form or reconnect an island.
Keep operational evidence beside the control system
The diagram shows owner monitoring. The microgrid controller, protection relays, synchronising equipment and hard-wired interlocks keep their own deterministic paths and authority.
- Wired
- Zigbee
- Edge
- Platforms
| Position | What it tells you | Reference | Sensor |
|---|---|---|---|
| Point of common coupling | Import, export, voltage, frequency and whether the microgrid is connected to the wider network | Retain PCC breaker state, meter identity, ratios, sign convention, time source and data quality DOE microgrids | ZMB-31 (on this page), approved meter and breaker states |
| Sources and storage | Measured power, availability, operating mode, battery state of charge, reserve floor, limits and alarms | Identify the exact controller, inverter, generator and BMS firmware behind every point IEEE 2030.7 | ZMB-31 (on this page), documented read-only registers |
| Retained and shed loads | Which load groups remain supplied, their demand, shed stage, restoration state and unavailable capacity | Measure suitable LV groups independently and preserve controller state beside physical demand DOE controller | ZEM-65 (on this page), suitable LV load groups |
Operating mode is evidence, not decoration. Store the requested mode, accepted state, breaker positions and measured result separately. A label that says islanded is not enough if the PCC state or electrical measurements disagree.
Identity and time make an event traceable. Record point name, equipment identity, firmware, units, scale, quality, source timestamp and collection timestamp. Without them, a post-event sequence can put actions in the wrong order.
One authority writes in each state. The approved microgrid controller coordinates PCC, sources, storage and loads. Monitoring clients remain read-only, and any market or remote dispatch request passes through the controller's defined arbitration and safety limits.
Explain each microgrid state in Edge
Build a state-aware record from the PCC, resources, loads and approved controller context. Preserve the source points beside derived events so an engineer can reconstruct the sequence.
- Use an explicit state model
- Distinguish grid-connected, transition, islanded, black-start, resynchronising, reconnecting and fault states. Define entry evidence, expected breaker positions and allowed resources for each state.
- Check the PCC balance by state
- In grid-connected operation, reconcile sources, storage, loads and grid exchange over aligned intervals. In an island, the PCC flow should be absent and the retained-load balance should close within declared uncertainty.
- Expose reserve and active constraints
- Trend usable battery reserve, generator availability, resource limits, retained demand and shed stage. Keep a limit's source and effective time so the record shows why dispatch differed from a request.
- Fail stale data visibly
- Set a maximum age for every input used in an event or balance. Withhold the derived conclusion when a required source is stale, and never present the last known state as a fresh physical result.
Commissioning checks
Commission the monitoring record with the microgrid designer and authorised site team. Observe approved functional tests without changing protection, controller logic or interlocks.
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The topology matches the single-line diagram
Trace the PCC, sectionalising points, sources, storage, retained loads, shed groups, auxiliaries and every measurement boundary.
Pass when each point has one electrical location and no flow is omitted or counted twice.
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Point identities and clocks are proven
Compare equipment labels, firmware, register maps, units, ratios and time sources with the approved point schedule.
Pass when the event record identifies each source and orders breaker, mode and power changes correctly.
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Operating states agree with physical evidence
Observe the approved grid-connected, islanding and reconnection tests and compare controller state with PCC breaker position and electrical measurements.
Pass when every transition has a coherent request, accepted state, breaker sequence and measured outcome.
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Loss of data has a safe monitoring outcome
In an approved test environment, interrupt one non-control monitoring input while leaving the controller and protection paths intact.
Pass when the point becomes stale, dependent conclusions are withheld and the control system is unaffected.
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Control authority and fallback are documented
Review every local and remote writer, arbitration rule, timeout, fallback mode, manual override and hard-wired interlock with the controls owner.
Pass when one approved authority acts in each state and loss of a request leads to the designed fallback.
Keep monitoring outside safety and market authority
This design creates an owner-side operating record around an approved microgrid. It does not qualify or control the electrical scheme.
- Edge does not replace the microgrid controller, protection relays, sync-check relay, PCC trip circuits, neutral-earthing arrangement, black-start logic or emergency controls.
- Islanding, energisation and reconnection require the applicable grid code, connection agreement, protection study, settings, witness tests and network-operator approval.
- Operational values do not become revenue, settlement or market-service evidence unless the responsible body has approved the meters, time source, communications and availability process.
- The BMS, PCS, generator controller and inverter retain their safety and equipment limits. This guide establishes no EpiSensor command path to them.
- A monitoring interval cannot prove sub-cycle protection or transition performance. Use the controller, relay and disturbance records specified by the scheme for those events.
Sources
- Grid systems: microgrids (opens in a new tab) (opens in a new tab) U.S. Department of Energy
- Voices of experience: microgrids for resiliency (opens in a new tab) U.S. Department of Energy
- IEEE 2030.7-2017, standard for the specification of microgrid controllers (opens in a new tab) (opens in a new tab) IEEE Standards Association
- IEEE 1547-2018, interconnection and interoperability of distributed energy resources (opens in a new tab) (opens in a new tab) IEEE Standards Association
- Engineering Recommendation G99 Issue 1 Amendment 10 (opens in a new tab) Great Britain Distribution Code
- Wireless 3-Phase Electricity Monitor datasheet (opens in a new tab) EpiSensor. Specifications, ranges and ordering codes.
Related
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Generator remote monitoring
An independent meter proves what the generator carried, the controller says what it thought it was doing, and the fuel signal says how long it can keep going.
- OverviewEnergy monitoring
- CalculatorThree-phase power calculator
- CalculatorInterval demand calculator
- GuideMicrogrid basics: components, operating modes and control
- GuideOperational monitoring, revenue metering and settlement
Third-party devices for this application
More in the Device Directory: Energy meters (62), Current transformers (7)
Map the microgrid states before choosing monitoring points
Bring the single-line diagram, point schedule, controller functional design, protection study and operating-state matrix to an engineer.