Project Overview & Design

Mitton ElectroNet developed a technologically advanced mobile substation design based on a design that had successfully been used for a 33kV unit in Greymouth. Mitton ElectroNet also provided procurement and project management services for this project.

The mobile substation features one 66 kV SF6 incoming breaker, one multi ratio 66-33 / 11-6.6 kV, 5 MVA, Midel 7131 filled transformer with OLTC one 11 kV vacuum feeder breaker, one local service transformer with back-up petrol generator, transformer protection and AVR Topcat RTU and SCADA via VHF radio and 48 V batteries and charger.

Added Value

The mobile substation enables the Client to provide a rapid response to transformer failure at any substation throughout their network. The mobile substation will also be used to facilitate transformer maintenance
at small, single transformer substations where total outages are no longer acceptable due to load profile changes.

The use of biodegradable, Midel 7131 transformer oil in the main transformer results in an environmentally
safe unit that does not require extensive bunding on the trailer or the ground when being deployed.

Project Outcome

Mitton ElectroNet Ltd delivered a new fully mobile 66/33/11/6.6 kV substation to Cromwell Substation for Delta Utility Services.

Mitton ElectroNet was chosen because of its specialist knowledge in Earthing Design, Modelling and Testing.

Project Overview & Design

The testing involves injecting 58Hz current into each earthing system to simulate an earth fault and create an earth grid voltage rise (EGVR). The EGVR is measured to determine the earthing system impedance, as well as touch and step voltages to determine if any hazardous voltages would be present in the event of a fault.

A number of the substations tested have been located in unique locations such as gold and coal mines providing our team with challenging and interesting working environments. Our test teams are fully equipped to handle challenging environments and most weather conditions- with the substations being located on the West Coast of the South Island, battling the ability to work in bad weather proved to be challenging.

Testing was carried out using low current off-frequency injection methods using a portable solid state injection unit and tuned voltmeters.

Project Outcome

All sites were tested successfully within the set time frame. Mitton ElectroNet provided a comprehensive report to Westpower Ltd detailing the earthing condition of their network and made recommendations regarding improvements  to mitigate any potential hazards deviations from industry standards and limits.

Project Overview & Design

The challenge for the Draughting Services team was to improve an existing Overhead Line Standard drawings for the client.

The intention of the standards is to give contractors a good understanding of how installation will look and fully dimensioned drawings that include a description of all the fittings required.

Solution

Mitton ElectroNet developed an innovative solution that combined 3D drawings and an automated material list to provide accurate quality drawings in a time efficient way.

Project Outcome

Mitton ElectroNet’s solution resulted in reduced future design costs. The 3D solution enables improved understanding with more efficient procurement, and improved quality of installation.

Project Overview & Design

Mitton ElectroNet was engaged to review existing communications schemes at Alpine Energy Ltd and to investigate and recommend a modernised and future -proofed communication architecture and topology. Mitton ElectroNet researched modern industry technologies and practices and suggested a highly resilient ruggedized IP network for the substation environment interlinked with a hybrid fibre optic and licensed/GURL radio bearer network. Cost economics, maintainability, reliability and a future proofed technology combined with integration of multiple services formed the key elements of the final design and equipment selection. Radio repeater site development, equipment configuration and commissioning plans were also developed as part of this project.

Project Outcome

Mitton ElectroNet was able to recommend a suitable scheme to increase Alpine’s network security, flexibility, functionality and maintainability. Since the completion of this design project, Alpine has begun an upgrade of their network using Mitton ElectroNet’s proposal.

Added Value

Mitton ElectroNet’s experience in communications enabled a cost efficient means of upgrading of the Apline Energy Network to providing a resilient and high quality network for years to come.

Project Overview & Design

Mitton Electronet provided design services that included the detailed modelling of the existing network, simulation of capacitor switching transients during point on wave switching failure, and analysis of transient recovery voltages to enable selection of an adequately rated capacitor bank circuit breaker. System overvoltages were also evaluated to ensure existing equipment and surge arresters were not adversely affected by the new installation.

Added Value

Mitton Electronet Ltd was able to combine the specialist knowledge in Transient Modelling and skills in high voltage design to allow the whole design to be completed by one company. This reduced costs and time, allowing West Power to have a single point of contact.

Project Outcome

The design & modelling completed by Mitton Electronet Ltd ensured that the Capactor bank was constructed successfully on time and on budget.

Project Overview & Design

Deep Stream Power Scheme is a new hydro scheme consisting of two new power stations, rated at approximately 3 MW each. It is located near Lake Mahinerangi and the existing Waipori Hydro Scheme. Along with the two new powerhouses, a new dam was constructed to form a small storage lake for the scheme. Water is diverted into the lake by a new roller gate from an existing diversion and then from the lake into a 8 km canal by a new radial gate. Each powerhouse is located sequentially along the canal with an approximate spacing of 3 km.

Mitton ElectroNet’s role was to design and manage supply, installation, construction and commissioning of all electrical aspects of the project. This included the generators and transformers, control and protection systems, WAN communication systems, power supplies for remote gate sites and transmission line construction.

Added Value

Mitton ElectroNet provided engineering services from planning through design construction, and commissioning. Delivering a seamlessly integrated solution to our client.

Project Outcome

Mitton ElectroNet’s design, construction and commissioning were all successfully completed.