Our company is struggling with a number of installations in the Tshwane (Pretoria) region of South Africa. The municipality (utility provider) has rolled out the installation of Conlog meters. The majority of these meters are overly sensitive to reverse energy detection. One of the meter models is the Conlog BEC42X (Single Phase).
Many of our installations consist of an ESS setup like the following: MultiPlus II 5kVA, BlueSolar MPPT Charge Controller, Color Control GX, Carlo Gavazzi Energy Meter, BMV700 and a Lithium Battery.
Many of these installations, in the Tshwane area, are experiencing frequent tripping of the Conlog utility meter.
Some forums have indicated that these meters are tripping at a point as low as 20W over 15 seconds - or some 300 Joules of reverse (export) energy detected. This is incredibly sensitive and clearly the root problem. However, this is very difficult to resolve with the municipality (utility provider) and they are mostly unwilling to assist.
We have had to resort to setting the grid set point significantly higher than desired, sometimes around 300W and have had to limit inverter power, in some instances to as low as 750W. With these restrictions placed on the system, we are mostly unable to process (store and discharge) all of the solar energy available from the solar array resulting in compromised economic performance.
What can we do to improve the control of export power to the utility?
It is inevitable that some export energy will be supplied to the utility in a grid-connected ESS system, but one observation that we have made is that the MultiPlus & Quattro inverters appear to react quite slowly AFTER a large load is switched off - this observation comes from the Color Control display panel where we can see the grid import/export as reported by the Carlo Gavazzi Energy meter, as well as the amount of power being discharged by the battery, as reported by the BMV700.
Once a large load is dropped, can the inverter not reduce it's power faster to avoid overshoot and subsequent export energy being supplied to the utility?
From this link, we see that the response time of ESS has been limited to 400W per second as per ESS version 162... but now we need a work around?
This thread comments on a similar aspect: https://community.victronenergy.com/questions/51697/victron-ess-et112-slow-response.html
After reading the above thread, can we not adjust the refresh rate and baud rate for the energy meter (Carlo Gavazzi) to aid the situation in swiftly recognizing the change in the grid import/export condition?
Alternatively, is the 100A:50mA Current Transformer a temporary solution for MultiPlus II ESS installations?
If this cannot be achieved with the ESS assistant, is there a combination of assistants that will allow us to operate in a similar fashion to ESS while overcoming the issues presented by the hard-coded rate limiting?
Thanks in advance for your input and suggestions.