Solar PV Connection to Existing Mine HV Network

Outline

PCE were engaged to provide power studies and electrical design for a NSW Coal Mine. This contract included construction documentation and detailed electrical design for the connection of a proposed 5000 x 400W solar array to the existing mine HV system.

Power Studies

Comprehensive power analyses were required, including load flow & short circuit studies, protection studies, harmonics studies and earthing & lightning protection studies. Load flow studies were undertaken for various combinations of grid power, PV power and power factor correction in and out of service, with the purpose of showing voltages and currents were acceptable. Inverter harmonic source data was used alongside 6-pulse VFD harmonic source modelling for existing VSDs to ensure AS/NZS4777 compliance. The studies were used for the Application for Connection to the Supply Authority.

Design

Extensive design deliverables were provided by PCE for the cable run, transformer kiosk and low voltage switchboard & inverter room. Cable run documents included route planning, cable specification installation details. Specifications for all electrical equipment were delivered, accompanied by switchroom plan and elevation, lighting locations and associated construction details.

Difficulties

With the connection specified between photovoltaic arrays and the existing HV network and existing protection, multiple requirements were introduced. To ensure compliance with the installation and safety requirements for PV arrays (including AS/NZS5033), and with Mining requirements, new design practises were required.