‘EMMA with EC’ in Action – 3 graphs

Export control and inverter stability with EMMA (with graphs).

The following graphs are taken from an EMMA test site near Kilmarnock in Scotland. The test site comprises:

  • a 15kW Proven wind turbine and
  • an EMMA SP15/45 with the optional Export Control add-on
    (‘EMMA SP15/45 with EC’)

The EMMA with EC unit performs three main functions:

  1. Diverts surplus power to a thermal store. While doing this EMMA holds export at or close to zero. This is the ‘Optimisation of Output Utilisation’ function, standard to all EMMA units, with or without the EC add-on.
  2. Limits export to the permitted limit. It does this when the thermal store is not available. This is the EC (Export Control) function.
  3. Keeps the supply voltage below the permitted limit to prevent the inverters tripping. This is the GVS function (Grid Voltage Stabilisation).

These functions are demonstrated in the graphs below.

Graph 1: EMMA Preventing Inverters from Tripping

The first graph below shows EMMA putting tiny pulses of power into the heaters to prevent the voltage rising above 254 volts and thereby prevent the inverters from tripping (see the solitary dark red line half-way up graph).

Without this control the inverters would have been tripping continuously, and the turbine output (and FIT payments) would have been very much reduced.

Click for Larger Version of Graph 1



Graph 2: EMMA’s GVS function in Action During a Storm

The graph below shows EMMA’s GVS function operating perfectly during a storm – or nearly perfectly, this was before its Grid Voltage Stabilisation cascade function had been enabled.

Click for Larger Version of Graph 2


Graph 3: Inverter Stability With and Without EMMA’s GVS Function

The graph below shows

  • the inverter on the test site tripping repeatedly (on the left of the graph) before EMMA’s GVS function was enabled;
  • EMMA’s GVS function being set up (centre). This shows a few trial runs with GVS on, GVS off… etc.; and
  • EMMA’s GVS function operating continuously (on the right).

Click for Larger Version of Graph 3

ELITE Control

The ELITE is the latest addition to the EMMA product family. While we consider it to be the Elite of power diversion and monitoring it is in fact EMMA's little sibling or as we call it EMMA lite.


EMMA Cascade

The modular heating system that can grow and grow


EMMA with Export Control

EMMA with EC allows for installs to have a greater renewable output than the Max Export Capacity (MEC) on site by diverting excess energy to heat.