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Lord Howe Island RenewableEnergy Project

Lessons Learnt Report: SystemHardening

August 2021

Lessons Learnt Report – System Hardening

Disclaimer and Funding Acknowledgment

The views expressed herein are not necessarily the views of the Australian Government. The Australian Government does not accept responsibility for any information or advice contained within this document.

This project received funding from the Australian Renewable Energy Agency (ARENA) as part of ARENA’s Advancing Renewables Program.

Lessons Learnt Report – System Hardening

1. Introduction

The project is situated on the world heritage listed Lord Howe Island and involves the design andinstallation of a 1.3MWp Solar PV plant with a 3.7MWh Battery storage System. The Solar plant is beingconstructed next to the existing powerhouse on the Island because the proximity to the existingpowerhouse provides significant technical advantages and the plot is one of very few open areas on theIsland which the Lord Howe Island Board has access to.

This plot (Plot 203) of land is also situation next to a section of woodland where a colony of Flesh FootedShearwaters breed seasonally.

There is a noticeable proximity of the project works to the breeding area and as such the ProjectTechnical Specification (RT019500-GN-SPC-0001_Rev0) and the conditions of consent required thatany fence constructed by the project not contain any barbed wire and provide clearance (150mm) atthe base to avoid entrapment of fauna (particularly ground dwelling birds) to allow breeding parentswhich happen to land within the fenced area to migrate back to the woodland.

The Technical Specification also requires adherence to AS5033: Installation and safety requirementsfor photovoltaic (PV) arrays. This standard requires restricted access for this specific installation sincethe DC array voltage exceeds 600V.

Restricted Access is defined by AS5033 Clause 1.4.61 as follows:

Access restricted by a barrier (e.g. by a perimeter fence or barrier with access only via apadlocked or equivalently secured gate or door); or

by location (e.g. a commercial roof where there is no fixed ladder or other ready means ofaccess).

This definition requires the construction of a fence or barrier that is effective in restricting entry to thefacility or access to the equipment via authorised access points that can be locked or closed to such anextent that only a key or the use of a tool will allow access.

Typical fence designs deployed on similar PV installations is shown in Figure 1.

Lessons Learnt Report – System Hardening

Figure 1: Typical permitter Fence Design

On World Heritage listed Lord Howe Island, this commonly used approach was assessed to beincompatible with the rare and endangered birds found on the Island. In particular:

The critically endangered and flightless Lord Howe Island wood hen needs a clearance at thebase of any fencing of 150mm to be able to freely roam.

The listed flesh-footed shearwater breed on the Island between September and May each yearand exhibit poor control in landing and take-off and could easily become entangled in barbedwire.

The Lord Howe Island hybrid renewable energy project team sought to identify an alternativehardening method for the site that would comply with the Australian Standards and would not presenta risk to the Island’s rare and endangered species of birds.

1.1 Considerations

AS5033 clause 3.1 states: “For non-domestic installations, at the Power Conversion Equipment (PCE)where the D.C. array voltage exceeds 600 V D.C., restricted access of the array cabling is satisfied wherethe cabling is in heavy duty conduit or is fully enclosed in an equivalent electrical enclosure which is notaccessible without the use of a tool up to and including the PCE input. If in accessible areas, theassociated protection and isolation devices shall also be fully enclosed and not accessible without theuse of a tool.”

Lessons Learnt Report – System Hardening

By this definition the project team set out to develop and design a series of access barriers to eliminatecontact by a person with high risk elements, either intentionally or inadvertent, without the use of atool. This process was focused on satisfying clause 3.1 by the definition of clause 1.4.61 collectivelyknown as system hardening.

The solution chosen needed to:

Provide sufficient barrier to prevent accidental injury, whilst allowing the free movement offlightless birds on the ground and avoid creating collision impediments for nesting sea birds.

Avoid creating other new issues or risks for the operation of the scheme. Be economically feasible within the project contingency budget. Be reflective of Lord Howe Island’s World Heritage listing which was provided in recognition of

the global significance of the Island’s outstanding natural beauty and biodiversity.

Table 1 includes the key high-risk plant elements and the associated hardening initiative.

PLANT ELEMENT HARDENING INITIATIVEPV Panel wiring and Panel junctionboxes

Installation of a 450mm wide cable trayincluding tray lid running continuously undereach row which will house the panel wiring,associated connectors and will cover all PVpanel junction boxes.

Tesla Inverter DC Isolator Fix staple to the BESS inverter door to enablethe DC isolator handle to be locked in the “ON”position by means of padlock. (Additionapproved by supplier)

SMA Inverter DC Isolator & installation Modify inverter to allow the DC isolator to belocked via padlock in the “ON” position. Allincoming and outgoing cables to be installed inheavy duty conduit. (Modification approved bysupplier)

HREP Distribution Board The HREP distribution board is fitted with anouter shell for compliance with IP requirements.These doors can be locked by means of a barrellock arrangement installed on each door.

Table 1: HREP System Hardening Initiatives

Lessons Learnt Report – System Hardening

2. Conclusion

A Solar PV and BESS installation of the size and nature designed for the Lord Howe HREP wouldtypically be surrounded by a 1.8m high cyclone fence with a 75mm gap at the bottom and threestrands of barbed wire at the top. Such a fence will satisfy the barrier requirements as described inAS5033 but will have a negative environmental impact and will not comply with the conditions ofconsent.

In lieu of a fence, a set of system hardening initiatives was designed and implemented to satisfy therequirement for a “barrier” and the requirement for the use of a tool or key to gain access to oroperation of potentially dangerous equipment.

The final system hardening initiative complies with the general intent of AS5033 with specificreference to restricted access. The design will not and was not intended to be vandal proof, which isalso the case with the use of a “traditional” perimeter fence. The proposed initiatives provide a barrierto prevent inadvertent contact of potentially live system elements and mandates the use of a tool orkey for access.

It is noteworthy that vandalism on Lord Howe Island is extremely low due to high reliance on tourismcoupled with the pride the community feel for the Island and its natural appearance. This culture ofrespect for the island in a small community notably reduces the likelihood of the risks discussed in thismemorandum materialising.

Lessons Learnt Report – System Hardening

Appendix A. Images

Figure 1: Hardening Tray covering PV Junction Boxes and containing DC Cabling.

Lessons Learnt Report – System Hardening

Figure 2: Hardening Trays

Lessons Learnt Report – System Hardening

Figure 3: Access restriction behind the cable trays.

Lessons Learnt Report – System Hardening

Figure 4: Hardening Tray installation prior to PV panel installation.

Lessons Learnt Report – System Hardening

Figure 5: Hardening tray cover lids.

Lessons Learnt Report – System Hardening

Figure 6: DC Cable hardening.

Lessons Learnt Report – System Hardening

Figure 7: DC Cable and inverter Hardening.