We often get asked how to interlock or interface Solar systems or other renewables with Generating Sets.

Please note: this is only required if the solar system is connected downstream of the Transfer switch, if the solar system is connected upstream of the generator & transfer switch it will not create issues discussed below.

Quite simply, the solar isolation/enable should be interlocked through an auxiliary contact on the Automatic, or manual, Transfer Switch (ATS) MAINS CLOSED signal.

This way the Solar System or NPU is only enabled when the MAINS supply is connected to the site load through the ATS.

As soon as the MAINS supply is not supplying the site load through the ATS the Solar System or NPU is disabled, thus allowing the generator to operate as required without interference from the solar system & potential damage to either system.

When the MAINS supply is again restored to normal operation supplying the site load through the ATS this will re-enable the Solar System or NPU which should begin to operate after a short MAINS restoration or ENABLE delay that should be part of the normal Solar System or NPU operation.

This technique ensures the Solar System is only actually isolated when the MAINS supply is not connected to site load, via the ATS, as the solar system or any other generating or storage devices should not operate in parallel with other generating devices (including diesel or gas generators) without interfacing controls to protect all systems. Disabling the Solar System on the MAINS disconnected signal also ensures the solar system has time to cycle off completely before the generator is placed on-line.

Some sites we have seen disable the solar system operation from a generator running signal (diesel or gas), this is not the preferred method of operation as the solar system will be switching on & off every time the genset is started & stopped either during normal operation or during generator maintenance or testing which could see several consecutive start & stop operations which could lead to premature failure of solar equipment. This method also may not allow the solar system time to cycle off completely.

Contact us on 08 8349 7854 to discuss a solution to effectively isolate or integrate renewables with Generating sets.