Cloud EMS – NPR Cannot Be Enabled When Backflow Power Is Set to 0

With the introduction of Cloud EMS and the Negative Price Response (NPR) feature, users can automatically prevent export during periods of negative electricity prices.

However, if an end-user previously set the inverter’s backflow power (export limit) to 0 W, NPR cannot be activated — even though the system may display “Saved successfully”.

This is expected behavior.

If export is already limited to 0 W, there is nothing for NPR to regulate during negative prices. Therefore, the feature is not actually activated.

Why This Happens

Some end-users configure their system to 0 W export because:

Their energy contract charges high export fees
They want to prevent any energy from being fed into the grid
Their grid operator enforces strict export limitations

When backflow power = 0 W, the system is already permanently blocking export.

Since NPR works by temporarily limiting export only during negative price hours, it cannot operate if export is already fully disabled.

Result:

The system shows Saved successfully
NPR is not actively enabled
No export behavior changes occur

How to Enable NPR Correctly

To use NPR, export must be allowed under normal (positive price) conditions.

Follow these steps (for the dealer/installer)

Step 1 — Adjust Backflow Power

Go to Digital O&M
Open the relevant inverter
Navigate to:
Settings → Meter
Locate Backflow Power
Change the value from 0 W to the allowed export limit

What Value Should Be Used?

In most cases:

The allowed export limit equals the inverter’s nominal AC power

However, verify whether:

The grid connection has a lower technical limit
The energy contract specifies a maximum export capacity

Always configure the legally and technically allowed export limit.

Step 2 — Enable NPR

After updating the backflow power:

Go back to the Cloud EMS settings
Enable Negative Price Response (NPR)
Save the configuration

Now NPR can operate correctly:

Export is allowed during positive price hours
Export is automatically limited during negative price hours

Expected System Behavior After Fix

Once properly configured:

Export occurs when electricity prices are positive
Export is automatically limited when prices become negative
The NPR feature actively manages export behavior

Important Note for Installers

If an installer encounters a situation where:

NPR appears enabled
No export occurs during positive prices
Or behavior does not change

Always verify that Backflow Power is not set to 0 W.