BTM Battery with grid limits allows small amounts of battery power to grid

[cpaulgilman]

Describe the bug

This PV-Battery / Commercial case with interconnection limit set to zero allows battery to discharge to grid. File for testing:
btm-grid-limits-allows-battery-to-grid.zip

This is a 300,000 kW / 2 hr battery with manual dispatch. It discharges a relatively small amount of power to the grid (~900 kW) approximately once a day in the timestep before the inverter AC power goes negative to account for inverter nighttime consumption.

Note that several battery parameters have been modified from the defaults to unrealistic values:

• Cell capacity is 280 Ah.
• Battery heat transfer coefficient is 100 W/m2K and environment temp is constant 0 degrees C (time series input).
• Dispatch SOC range is 0 to 100%.
• Manual dispatch discharge rate is 100%.

To Reproduce

1. Run simulation for "test case" in attached file linked above.
2. Note non-zero "Electricity to grid from battery AC" in outputs.

Expected behavior

Battery should not discharge to grid when interconnection limit is zero.

Operating System and Version

• OS: Tested in Windows
• Version: SAM 2024.12.12