Definition
Microgrid refers to a small autonomous power system composed of distributed power sources (such as photovoltaic, wind power, gas turbine, etc.), energy storage systems, loads, and control devices, which can operate in grid-connected or island mode. A microgrid achieves coordinated control of sources, network, load, and storage through an Energy Management System (EMS), supporting energy monitoring, demand-side response, charging stations, and other flexible load scheduling. Compared with the main grid, microgrids offer advantages such as local autonomy, improved power supply reliability, and the absorption of distributed renewable energy. In cross-border scenarios, microgrids can be deployed in overseas parks, ports, charging stations, using IoT to achieve remote energy monitoring and operations and maintenance, and the terminals need to support one card for multiple countries to ensure cross-border connectivity.
Technical Features and Architecture
The microgrid technology architecture includes:Power Source Layer—— Distributed sources such as photovoltaic, wind power, and gas turbines;Energy Storage Layer—— Battery storage, flywheel storage, supporting peak shaving, valley filling, and islanding support;Load Layer—— conventional loads,EV Charging StationAnd other flexible loads;Control layer—— EMS energy management,IEC 61850And other communication protocols,Energy monitoring; Grid-connected/islanded——exchange power with the main grid when grid-connected, operate independently when islanded. Together withEnergy monitoring, real-time power and energy monitoring can be achieved; together withCharging Station, orderly charging can be supported,Demand SideResponse. In cross-border scenarios, microgrid EMS andDevice Management PlatformCan be remotely connected via IoT SIM cards, supporting unified monitoring across multiple countries.
Application in IoT and cross-border scenarios
Microgrids are widely used in:Parks and buildings— Distributed energy and energy storage for industrial and commercial parks, data centers, and hospitals;Charging Station——Charging StationEquipped with photovoltaics and energy storage to achieve green electricity charging and peak shaving and valley filling;Islands and Remote Areas— Off-grid or weak-grid microgrids on islands and mining areas;Cross-border Projects— Microgrids in overseas parks and ports,Charging StationAchieved remotely through the Internet of ThingsEnergy monitoring, Device StatusMonitoring,Fault Alert. Cross-border new energy projects and global charging networks rely on microgrids and the Internet of Things to achieve intelligent management and remote operation of distributed energy.
SimtoLink provides connectivity for microgrid-related devices across more than 200 countries, supporting cross-border energy monitoring and remote operation and maintenance.
Where communication should stop in grid-tied and islanded operation
A microgrid is a small system that can keep a local electrical balance both grid-tied and islanded. Local controllers coordinate sources, storage, load, and switches. While grid-tied it exchanges power with the external grid. While islanded it must keep supplying power by its own voltage and frequency control. An external network outage is not a reason for local control to be lost. An IoT connection here mainly carries monitoring, the export of settlement data, and slower energy-management setpoints. It is not the channel for a protection trip.
For a cross-border campus or port, list in advance which local links must still work after islanding, and which reports can wait for the public network to return. Energy management may keep using the last permitted set of setpoints after the overseas platform is lost, or fall back to a local schedule. The source of a setpoint, how long it stays valid, and what happens on a limit crossing belong in the controller, not only on a cloud screen. Switch state at the point of interconnection should follow the local signal. If charging load takes part in regulation, the command's lifetime must be shorter than the user session. An expired command must not execute suddenly when the network returns. The metering point is calibrated on its own. Inverter self-reported energy should not replace the revenue meter.
Using a public-network heartbeat in place of a protection interlock
Reading "the cloud can still see a heartbeat" as "the microgrid is operating normally" is a dangerous simplification. A lost heartbeat may only be a cross-border cellular failure, while the electrical system is still grid-tied. A healthy heartbeat can also occur while the site is already islanded and locally limiting load. Protection and control should close their loop inside the station. Another error is, after the network returns, for the cloud to replay in one burst the power commands that piled up during the outage, pulling storage or charging load to an expired target.
An islanding test that only passes in a domestic lab, and is then taken to mean the communications conditions at an overseas port are the same, leaves the site without monitoring that should have stayed local when the public network is unavailable. Rehearse local alarms and load limiting with the path toward the overseas platform disconnected. When revenue metering and inverter readings diverge for a long time, check the instrument transformers and the tariff periods first, rather than raising the reporting rate. Once the site controller is on the intranet, the remote side should see only the operating summary that is allowed to leave. It should not rewrite protection settings directly.
The criterion of an islanding drill is that local voltage and frequency stay under control and load drops out in the planned order, not whether the overseas platform can still see a heartbeat. During the drill, disconnect the uplink on purpose and record which monitoring still updates on the local screen. After the uplink returns, check that no expired power command was executed. Protection settings should be the same before and after the drill.