Power grids were originally built to distribute energy from a central source to the individual consumers. The increasing amount of PV power installed has changed this requirement.
Ancillary services are already required in some countries to improve the stability of the grid. These services require the grid operators to be able to control the output and regulate the amount of reactive power from the PV plant.
The function „X Percent Fixed Regulation with the calculation of self-consumption“ offers an innovative solution to minimize losses that result from the fixed regulation.
Only a consumption meter is needed to implement the intelligent x% regulation. This records and transmits the self-consumption of power to the Solar-Log™. The Solar-Log™ calculates amount of power being fed into the grid based the self-consumption of power and the current amount of power being produced by the inverters.
Before the feed-in power (the difference between the current production and consumption) exceeds the maximum amount specified, the inverters are regulated accordingly. This means that a PV plant can continually generate at full power by taking self-consumption into account and adjusting output accordingly.
This function can also also be used to fulfill the feed-in requirements of 0 kW. However, due to different inverters, it cannot be guaranteed that absolutely no power is fed into the grid for the reduction to 0 kW. Solar-Log™ assumes no liability for power reductions. An additional external meter is needed to implement this function.
Remote controlled active power reduction with the calculation of self-consumption
The signal to reduce active power is generally sent via a ripple control receiver. This device can be controlled from the grid operator's control center and the commands can be relayed via potential-free contacts. The Solar-Log™ PM+ product line comes with an additional interface for potential-free contacts. Up to 2 ripple control receivers can be connected to this interface, one for power reduction and one for reactive power control.
This function is an extension of the remote controlled active power reduction. Here the current amount of self-consumption is taken into account in determining the reduction level. By logging the consumption with an extra meter, only the power output as signaled by the ripple control receivers is delivered to the feeding point.
In combination with our software Solar-Log WEB, you can generate reports on the power output control and current losses with just a few mouse clicks.
Monitoring in the Megawatt Range
Feed-in management is becoming a more common requirement for large plants. In contrast to simple feed-in management, a response signal with the actual amount of feed-in power is also required. That is why most grid operators deploy remote control technology. The Solar-Log™ I/O Box can receive and send the wide range of signals from various grid operators.
This function is only available with the Solar-Log 2000 PM+. When used with the Utility Meter, measured values such as reactive power, voltage and currents are reported back.
Customized solutions to implement feed-in management requirements
In practice, each distribution grid operator stipulates their own signalization variant in the technical connection requirements (TAB). To fulfill the requirements from a particular grid operator, Solare Datensysteme offers a grid company specific "PM+ Profile." This package includes hardware that is adjusted to a company's remote control technology and a profile file.
Master Slave Regulation for Large Plants
Solar-Log 2000 data loggers are linked together via Ethernet to implement feed-in management at plants in the megawatt range. This linking over the network allows the control signals from Ripple Control Receivers to be interchanged.
The grid operator‘s signals are received by the Solar-Log 2000 PM+ (master) and distributed to the connected inverters via the Solar-Log 2000 (slaves). The master can be connected to up to nine slaves in this setup. Linking the Solar-Logs™ together over the network helps to implement complex requirements (several plant parts, feeding points and inverters from several manufacturers).
Several Utility Meters can be used within a master/slave installation, as long as, for example, several feed-in points are available.
Other functions such as the fixed value cos phi shift factor or performance-related cos phi functions can be implemented without additional measurements.