Embedded distribution network

Customer case study

About the customer

DevelopmentWA is the State Government’s central development agency, with a diverse portfolio of industrial, commercial and residential projects across Western Australia. 

Being a strong proponent of innovation through its ‘Innovation through Demonstration’ delivery ethos; DevelopmentWA via the Industrial Lands Authority, has delivered the State’s first green-titled renewable energy industrial microgrid in the Peel Business Park in Nambeelup. 

• Developing an AS3000/AS2067 compliant ‘behind-the-meter’ embedded network design using Western Power’s standard equipment and design specifications for a regular subdivision network;
• Having to incorporate a ‘future’ Western Power intake, customer switch room and cable ducting system within the design, with limited load data;
• Incorporating both current and future microgrid control functionality with additional provision for future ‘primary’ type switchgear, within a standard 22kV Western Power switch room.
• Incorporating Western Powers newly deployed Low Voltage Public Electricity Network Distribution Assembly (LV PENDA) kiosks and switchgear ‘on the fly’, whilst under tight time
• (The transition occurred mid-way through this project, which presented many challenges and risks which required careful management);
• Having to incorporate earth leakage protection in street lighting circuits within Western Power’s standard substation configurations;
• Interfacing with the many project stakeholders.

How did Western Power solve the customer challenge?

• Meticulous design of both 22kV switch rooms  and associated cable pit and ducting systems;
• Utilising Type 1 PENDA kiosks with carefully selected protection in lieu of Universal Pillars to achieve compliance with ‘behind the meter’
• standards. This also eliminated the requirements for a customized switchboard to supply     each property.
• We use Type 1 kiosks on rare occasions for site/network specific purposes. These Type 1 kiosks are largely unknown to most Western Power customers, so having our distribution experts on the job ensured an ideal solution wasn’t missed;
• Re-purposing ‘customer’ fuse-switch-disconnectors for transformer incomer protection to limit energy
• let-through in accordance with AS/NZS 3000;
• This allowed us to utilise standardised and rigorously tested Western Power Type 2 PENDA kiosks;
• Modified arrangement of Western Power’s standard Non-Modular Packaged Substation (Non MPS) to incorporate a low-cost streetlight protection switch -board with earth leakage
• Cascading was implemented to reduce fault levels and switchgear costs in switchboards.

The following snapshot provides an overall picture of the size/scale of the project:

• Intake switch room for connection of 3x 22kV feeders from the Western Power grid;
• 1x 22kV customer switch room (15 MVA capacity with 8x 22kV feeders to accommodate expansion);
• 22kV customer switchgear provision for the purpose of future embedded generation (incl. protection and metering current transformer (CT) and voltage transformer (VT) cubicles), for compliance with Western Power technical rules;
• Provision to connect 1x neutral earthing compensator for future islanding capability;
• Future intake switch room for increased capacity and/or supply security;
• Future customer switch room to future-proof the customer installation;
• 5x outdoor 22kV switchgear kiosks;
• 4x outdoor 630kVA step-down transformers (2,520kVA total);
• 10x LV Public Electricity Network Distribution Assemblies (PENDA);
• 7x LV switchboards;
• ~1,700m of 22kV feeder cabling;
• ~830m of LV feeder cabling;
• ~670m of streetlight.

How did the customer benefit from having Western Power involved?

• Having in-house experts with comprehensive knowledge of the Western Power equipment, materials and standards allowed us to identify and develop various solutions which resulted    in unprecedented benefits for all stakeholders;
• The embedded network design for the microgrid is backwards compatible to a standard Western Power subdivision network design. This reduces the operational risk should the private network ever need to be operated by Western Power in a standard subdivision configuration;
• Assurance that all critical electrical distribution equipment and materials used within the private network are reliable;
• Assurance that any future additions and/or replacements within the private network will be readily available through Western Power.

What was the outcome?

Our Design Consultancy provided a safe, sustainable and constructible design solution in line with the design objectives. This allowed the customer to successfully complete and hand-over the project to the end-user.