FAQ

The system stores by default a daily logfile on the SD card of the RCC and/or Xcom device. However, in order to have a complete system backup, including the logfiles, the current configuration parameters and the system messages, the function "Save all files (system backup)" should be used. Please go to RCC settings and follow the next steps:

The following items will be stored in the SD card:

• Events log
• RCC-02 Console parameters
• xtender, variotrack, variostring, BSP parameters

ATTENTION: Please bear in mind that this function with a 9 Xtender system could take up to 15 minutes

Once the backup is finished, please take out the SD card from the RCC-02 console. Then you could copy all the folders and files in the SD card using a computer.

Please insert again the SD card in the RCC-02 console when the process is finalized.

The latest software version, Xtender System Update (RXXX) is always available on our Studer website in the Software and  Updates  section.

A software upgrade may be necessary during system commissioning, when adding a device to an existing system, after a device has been serviced, or to take advantage of a new function or parameter. When in doubt, contact Studer Innotec before performing the software update.

When you download the latest software release, you will have in the computer a zip folder containing:

Please copy the 02 Folder into the SD card of your RCC or Xcom device and insert the card in the device.

Please read carefully the Updating procedure (PDF) before performing the update.

RCC

The RCC will beep when the SD card is correctly inserted. Then confirm the update by pressing ok. The update is completed when the RCC displays the message "The update is finished" (051).

Xcom

The Xcom will blink red when the SD is inserted. The update will start automatically. The update is completed when the LED indicator is green.

ATTENTION: The updating procedure can take between 3 and 30 minutes. During this time, it is normal that the devices make audible signals.

The update should be performed in all the RCC and Xcom devices in the system (all the devices having an SD or microSD card). All the Studer products in a system should have the same software version.

The latest software version is always available on our Studer website in the Software and Updates section.

A software reset may be necessary in case of errors or problems in the system, in order to restore the factory settings and update all the devices in the system with the same software version.

When you download the latest software release, you will have in the computer a zip folder containing:

Please modify the name of the folder 02 to 03. Then copy the 03 Folder into the SD card of your RCC or Xcom device and insert the card in the device.

The process will be then similar to the process described in the FAQ  Software Update.

Please read carefully the Updating procedure (PDF) before performing the reset.

RCC

The RCC will beep when the SD card is correctly inserted. Then confirm the update by pressing ok. The update is completed when the RCC displays the message "The update is finished" (051).

Xcom

The Xcom will blink red when the SD card is correctly inserted. The update will start automatically. The update is completed when the LED indicator is green.

ATTENTION: The software reset will delete all the previous system configurations. After the reset, please make sure that the required and critical configurations are performed before turning on the system.

The update should be performed on all the RCC and Xcom devices in the system (all the devices having an SD or microSD card). All Studer products in a system should have the same software version.

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For grid connected systems, adding battery storage provides a back-up energy source in the case of grid failure. The Studer standard application maintains the battery fully charged and supplies loads using solar and grid energy. If grid injection is authorized, excess solar energy is exported to the grid. Otherwise, with standard settings, excess solar energy is not used.
With the self-consumption application, the Xtender system allows the battery to be discharged at night in order to store excess solar energy during the day, and thus increase the amount of solar energy consumed onsite. 

The following options are available for configuring the self-consumption in your Xtender system:

1)      Battery priority function

By activating this function (1296) there is a battery priority voltage (1297) as reference and the behaviour of the Xtender will be different if the battery voltage is above or below this level:

·         Battery voltage above battery priority voltage

o   The battery will be charged only with energy coming from Variotrack/Variostring (solar) and not from the grid.

o   The AC-in input limit will be automatically reduced from the value set by the user (1107) to a minimum of 1Amp

·         Battery voltage below battery priority voltage

o   The battery will be charged from both Variotrack/Variostring (solar) and from the grid (AC-in). 

o   The AC-in input limit remains fixed at the value set by the user (1107)

 

Advantages:

·         The grid is always available to support in case of peak of demand on AC-out

·         The Xtender is always at transfer/boost/charger function. There is no transition from one function to another

Disadvantages:

·         There is always a minimum of 1 Amp consumed from the grid. It is not possible to reach 0 consumption from the grid.

There is some excess of solar energy that will be not used

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2)      Grid as generator function

In this case we use the grid as if it was a generator. The Xtender will be off-grid as soon as the battery level is good (according to battery voltage). When the battery voltage reach a certain level (1247, 1250, 1253), the Auxiliary Contact 1 from Xtender will be activated. The Remote Entry will be automatically activated according to Auxiliar 1 status. The Remote Entry will allow the connection to grid by disabling the transfer relay prohibition (1538). 

Once the battery is charged and the battery voltage reaches the deactivation voltage (1255), the Auxiliary 1 will be deactivated, deactivating the Remote Entry and therefore forbidding the transfer relay again. The Xtender is again off-grid with 0 consumption from the grid.

Advantages:

·         The self-consumption of solar energy is maximized in comparison to the first option.

·         When the Xtender is off-grid the consumption from the grid is 0.

Disadvantages:

·         There is a micro-shutdown (max. 15ms) during the transition from grid connected to off-grid.

·         In case of peak of demand in off-grid mode, the Xtender will not have support from the grid and risk of overload is higher.

Self-consumption with Lithium Batteries (xcom-can)

Additionally, when the Xtender works with Lithium batteries that are communicating through the Xcom-CAN bridge, the self-consumption could be easily configured thanks to the "SOC for backup" parameter {6062}, by default set to 20%. 

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AC Coupling is a term used to describe systems that combine grid-tie inverters (usually feeding all energy produced to the grid) and battery-based inverters (usually for off-grid or backup applications).

Grid-tie inverters or solar inverters convert the variable direct current (DC) output of a photovoltaic (PV) solar panels into a utility frequency alternating current (AC) that can be fed into a commercial electrical grid or be used by a local, off-grid electrical network. A grid-tie inverter synchronizes with an existing sine wave (grid) and shuts down upon a grid failure.

Today many manufacturers have included "frequency shift" behaviour on their grid-tie inverters. This allows the grid-tie inverters to reduce their power output depending on the grid frequency. 

One or various solar grid-tie inverters can be installed in an Xtender system, coupled on AC. The system will work as described below:

1)      AC Coupling with a Xtender Off-grid system

When off-grid, the Xtender is forming the grid with energy from the battery, using the inverter function. In this case, a solar inverter can be connected on the AC output of the Xtender. It will synchronize with the grid created by the Xtender and will feed its solar production into the grid to supply the loads and charge the battery.  

When there is an excess of solar production and the batteries are full, the system will need to limit the solar production. We can use the frequency control function from the Xtender, that will increase the frequency of the AC output according to the battery voltage. When the battery is fully charged, the solar inverter will stop its production, thus both the battery and the system are perfectly secured.

The frequency control function is activated by setting the parameter {1549} "Inverter frequency increase according to battery voltage" to YES.

2)      AC Coupling with an Xtender connected to the grid

When connected to the grid, the Xtender will synchronize with it and close the transfer relay. In this case the Xtender acts as a current source inverter. Both the voltage and frequency are set by the grid and the Xtender synchronizes with them and exchange current.

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The solar inverter connected in the system, will feed solar energy that will be used directly by the loads and to charge the battery through the Xtender. In this case, the Xtender can't do any frequency control (the grid is controlling the frequency), therefore, the excess of solar production from the solar inverter will be then fed into the grid.

3)      AC Coupling with an Xtender connected to a generator

Similarly, as when the Xtender is connected to the grid, the Xtender connected to a generator will synchronize with it and close the transfer relay. Again, both the voltage and frequency are set by the grid and the Xtender synchronizes with them and exchange current.

The main limitation of this situation is that it is not possible to feed energy back to the generator, as it will damage the machine. For safety reasons, it is recommended to use the Xtender's Auxiliary contact to open a circuit-breaker isolating the solar inverter from the Xtender inverter when the generator is working. During times when the generator is not used, the system will work as described in the off-grid situation (1).

AC Coupling with Lithium batteries

To enable control of a solar inverter connected on AC-Out with frequency shifting by the Xtender in off-grid mode, parameter {6072} must be set to “Yes”. This gives access to two sub-parameters:
- the first {6073} defines the frequency delta from the user frequency (e.g. 50Hz) at which the power derating of the solar inverter begins,
- the second {6074} defines the frequency delta from the user frequency at which the power derating of the solar inverter reach 100%.
The frequency shifting is performed according to the maximum charging current allowed by the Lithium battery.

 

{6073} has a default value of 1.0 Hz, which makes the frequency to start derating equals to 51 Hz.
{6074} has a default value of 2.7 Hz, which makes the frequency to reach 100% derating equals to 52.7 Hz.

A third parameter {6086} allows to prioritize the ac-coupling instead of the solar charger energy in off-grid mode only. When the ac-coupling produces enough energy to match the battery required charging current, the solar chargers stops producing and only the solar inverter is regulated.

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There are two communication solutions available for your Xtender system to communicate with the Studer Portal. The interface allows for remote interaction with the installation exactly as if on-site with the remote control RCC-02/-03, including:

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These solutions are:

·         Xcom-GSM

This system includes a 3G Modem to insert your local SIM card with data package for GPRS or 3G internet connection.

·         Xcom-LAN

This system includes a LAN Modem to connect with your LAN router for internet connection.

To use 4G or Satellite connection, the Xcom-LAN allows to connect a 4G Modem or Satellite Modem for the internet connection, instead of the LAN router. The 4G or Satellite modem are not provided by Studer Innotec.