Solar Reverse Panel

Some commercial Solar PV installations are for self-consumption only and grid export is not permitted. While this may be fine on a working day, for a week-end or a holiday the PV generation may exceed the demand. The Grid Protection Relay mandated by the Network Provider would trip the Solar Generator under such a situation. This causes inconvenience and would result in loss of production. OZTRON Reverse Power Controller (RPC) actively modulates the solar inverters even under rapidly fluctuating loads and varying solar output to ensure that the solar power is always maintained just below the consumption level and tripping is avoided.

Solar Reverse Panel

The Reverse power protection panel is located close to the Solar AC distribution board. It can operate in stand-alone mode or interface with the Grid Protection Relay for added features and simpler installation. The grid voltage provides the power supply for the relay energising circuit and phase reference for the phase sensitive detector. Current reference to the detector is taken from generator load current The output from the detector is compared with a reference which is set by the trip set point potentiometer. When the set point value is exceeded an electronic trip operator to energise the relay circuit though an adjustable time delay.


  • Smooth control
  • Compatible with popular models of inverters
  • No moving parts or relays u Minimum wiring
  • Quick response, in milliseconds, not minutes
  • Accurate control u No start-stop operation for inverters resulting in loss of production
  • No restriction on sizes of inverters
  • Self-resetting
  • Adjustable set point
  • Adjustable time delay
  • LED trip indication
  • 2 pole relay contacts
  • Internal Differential (factory settable only)
  • With the proliferation of solar PV systems, the Electrical Supply Utilities are becoming increasingly concerned about voltage rise caused by solar systems exporting power to the grid when the customer’s load is not high enough to use all of the power generated by the solar system. This may be on weekends or public holidays.
  • The systems can be turned off during these times, however you will lose the efficiency and don’t then cover basic loads that may be much less than the maximum capacity of the solar system.
  • When solar systems generate more power than the load required at any particular time, the excess load is pushed back to the mains network and can cause voltage rise. Many of the transformers and mains network assets were not designed to manage this reverse power flow.
  • Approvals for solar system installs can be dependant on
    1) if excess power will be available &
    2) if the local grid can accept it.
  • Sometimes approvals for even small (5KW) systems are not available.
  • HLP Controls have a system (PE-200) to prevent the export of power during excess power production while still utilizing the solar power to maintain efficiency.
  • The PE-200 System monitors power flow direction and then can control the inverters to reduce power generated to match the power used on the premises.
  • This
    - maximises the use of solar power
    - maximises return on investment, &
    - keeps the power utility companies happy by not exporting excess power to the grid.
  • The PE-200 is easily installed and set-up. The export power limit is easily changed for situations where an export limit is set.
  • For instance, say on a 30KW solar system you are allowed 5KW of export.
  • In this situation the 5KW export is set as the export limit and all control will be set around this figure.
  • There are two types of inverters that can work with the PE-200.
    1 - Inverters such as the Trio PMU & SMA cluster controllers use an analog control signal.
    2 - The PE-200 can control the system to within 1% of total power.
    Note: 1 x PE-200 can control up to 50 inverters.
  • This system is pre setup and tested, you just need to install.
  • The end result is the same - more solar systems can be installed and each one is used more efficiently.
  • Parts Required:
    • Each system will require:
    1) An inverter with an analog interface Like the ABB- Trio or power one (ABB-PMU is included) 2) CT’s installed on site to measure the grid current;3 Standard CT's are included (200:5 Solid core) 3) A PE-200-1 4) A PE-200 spec sheet with all items filled in; 5) A qualified electrician to install the PE-200.
  • For systems when the Electricity Authorities require a generator protection relay, we match the PE-200 Zero Export Controller with an IEC Approved Protection Relay such as the Fanox SIL-G. This ensures compliance with the Utilities protection requirements and are typical on larger systems over 30KW (dependant on the Utility and the approval conditions).
  • Full system drawings are available for all configurations.
  • The PE-200-SILG is in a metal outdoor enclosure 600 x 600 x 180mm.
    The unit has an inner door with all of the controls mounted inside.
    This includes an IEC Approved generator protection relay which meets Australian standards. The protection relay includes reverse power, ROCOF, over-voltage, under-voltage, frequency, power and voltage measurement, etc.
  • A 140 Amp contactor is mounted in the system, which is controlled by the protection relay to disconnect the solar power should any parameters be exceeded (contactors up to 400 amps are available). This is typical of larger (ie: greater than 100KW) solar power requirements. The generator protection relay is often required by the Utilities as a ‘fail-safe’.

This unit is supplied wired, tested and programmed to your specifications, READY TO INSTALL! All hardware included.