Process Description
Simtronics’ Green Energy Microgrid simulator represents a small electric grid supplying a manufacturing facility with electric power produced by a wind farm, a solar photovoltaic (PV) farm with battery storage, a pair of swing-duty diesel engine-powered generators and a main grid connection with power import and export. These types of microgrids are becoming very commonplace as the technology of green energy equipment improves and capital costs decrease. The Microgrid normally operates in island mode where it is disconnected from the main electrical grid. The voltage and frequency of the Microgrid is under control of one of the Diesel Generators in this situation.
The simulator includes key power protection systems to provide realistic system behavior in the event of improper operation. A complete set of instrument and equipment faults are included to provide realistic scenarios for microgrid operator response training. The main electric-powered equipment in the manufacturing facility is also simulated and controlled by the operator. This allows realistic load management during normal and emergency microgrid operations.
A full range of operations can be practiced and mastered on the simulator including startup of the microgrid in both main grid-connected mode as well as in island mode, planned shutdown, emergency shutdown and equipment/instrumentation troubleshooting and recovery. Synchronization of the islanded microgrid with the main grid to connect the systems while operating the manufacturing facility can also be practiced. Also, management of the microgrid grid during dawn and dusk transitions can also be practiced as well as during transitions to no wind or high wind conditions.
The Wind Farm produces direct current electricity at 480 volts which is combined with the same from the Solar Farm in the DC Power Combiner. The Wind Farm consists of five Wind Turbines, all of which are normally in operation. The Solar Farm consists of 10 strings of solar panels, all of which are normally in operation. Power from the DC Power Combiner is routed to the Direct DC Inverter to convert the 480 VDC electricity to 3-phase 480 volts alternating current. Some or all of the electricity from the DC Power Combiner can be routed to the Battery Array. Battery storage of electricity allows smoothing out of the flow of electricity from the Wind Farm and the Solar Farm to the Hybrid Converter for times when power production from these sources drops off, such as at nighttime.
3-phase, 480 VAC alternating current electricity from the Direct DC Inverter is sent to the Direct DC Inverter Isolation Transformer which keeps the wiring of the Direct DC Inverter completely isolated from the Microgrid’s wiring. This is done to prevent galvanic corrosion in the systems. No voltage change occurs across the transformer and electricity flows from the transformer into the Microgrid’s 3-phase transmission line.
Power from the Battery Array is routed to the Battery Inverter to convert the 480 VDC electricity to 3-phase 480 volts alternating current. Normally, the Battery Inverter is off during the daytime when the Battery Array is being charged. The Battery Inverter can be set to automatically start when the power production from the Wind and Solar Farms drops below a set value. The Battery Inverter can also be set to automatically provide backup power to the Microgrid in case power is lost from the Diesel Generators. This helps ensure uninterruptible power to the Manufacturing Facility. The 3-phase, 480 VAC alternating current electricity from the Battery Inverter is sent to the Battery Inverter Isolation Transformer. No voltage change occurs across the transformer and electricity flows from the transformer into the Microgrid’s 3-phase transmission line.
There are two packaged, diesel engine-powered generators that directly generate 3-phase, 480 VAC electricity. One of the Diesel Generators is normally in service and is controlling the voltage and the frequency of the Microgrid. The other Diesel Generator is on standby. The Diesel Fuel Storage Tank supplies diesel fuel to the generators. The power produced by the operating Diesel Generator will vary as power output from the Wind Farm and the Solar farm vary with daytime, with the weather, and with wind conditions. The power output of the Diesel Generator will also depend on the power consumption in the Manufacturing Facility.
The Diesel Generators include supervisory logic that allows selection of the primary generator when in island operation, auto-starting the idle generator on a failure of the operating generator and a function to synchronize the Microgrid’s frequency, phase and voltage with the main power grid.
The Manufacturing Facility has 6 large electric power consumers (2 compressors, 2 large pumps and 2 large industrial ovens) as well as lighting and HVAC power consumption. The Microgrid operator has control over this equipment in order to simulate power load shedding and load building operations in concert with Microgrid operations.
Additional detailed process and instrumentation drawings are provided to show the details of equipment and instrumentation in Simtronics’ Green Energy Microgrid simulator.