Grid Protection Units

At BCJ Controls we support solar installers by building grid protection units to meet the utility's requirements including solar monitoring, PLC ramping, ethernet, wifi and 3G.

What is Secondary Protection?

Secondary protection is the protection after the solar inverter and before the grid. It is comparable to Primary Protection, which is within the inverter. Secondary protection is generally used where the installation is greater than 30kW and often includes Anti-Islanding protection, over/under voltage, over/under current and frequency protection.

ABB 30kW Solar Protection Relay
30kW Solar Protection Relay ComAp MainsPro

Protection Units for 30kW+ Solar

The utility (or DNSP) will normally specify extra protection for installations over 30kW. Our Secondary Protection Units reflect the requirements of the DSNPs when connecting to the grid.

Our control and protection boards can offer the following features:

  • Mains Disconnect / Anti-Islanding Protection Function
  • Suitable for up to any number of inverter inputs
  • Plug and play easy installation
  • Technical Support Available
  • Powder coated IP65 enclosure
  • Approved in all states
  • Made in Sydney to Australian Standards



Solar Protection Relay

Export Allowed

Some DNSPs may allow you to export as much power as you want to the grid. Here you have to have the minimum standard of relay to protect the power quality being exported. For these applications a relay such as the ComAp MainsPro is suitable.

Zero Export

Some DNSPs limit the amount of power that you can export onto the grid. As well as power quality protection, they require that the solar system has protection so that it doesn't export more power than allowed. Here we use a relay such as the ComAp InteliPro.

30kW Solar Protection Relay MainsPro IntelliPro Relay



Using CTs, Solar production and energy consumption can be viewed remotely with the eGauge monitoring device. Records are stored for the most recent 30 years.


This remote access data logger can be used with weather stations for sophisticated site information. Allows the installer to carry out Operations & Maintenance Contracts.

 PLC Controller

For ramping control options we use a Programmable Logic Controller. This is the industry standard for reliability and robust operation.


Our boards can be fitted with an optional HMI display. Standard size is 5”, but we are happy to accommodate any custom requirements for your project.

LGC Meter

An LGC Meter can be installed within the grid protection unit to allow the owner to measure the production of Large-Scale Grid Credits.

Motorised Circuit Breaker

We make use of MCBs to consolidate isolators and contactors, as a space saving design feature.

Stainless Steel Enclosure

Recommended when the enclosure is to be mounted outdoors.


For additional communications such as remote monitoring and reporting, we can install an industrial-grade Ethernet hub.


For long distances, or for the simple convenience, we can incorporate 3G-capable modems with an industrial rating into our boards.


Reliable 3G communication may be available depending on the location