Meglab’s Cost-Effective Co-Generation Solution

Meglab’s Cost-Effective Co-Generation Solution

Energy consumption is a huge cost for any mining company.  In Ontario, mining companies subscribe to energy ‘plans’ with Hydro One, an energy producer and distributor.  These plans are similar to our common cell phone plans: you have a certain amount of data or – in the case of mine – energy, and if you go over your allocated amount, you pay a higher cost for the excess.  In addition, Hydro One’s billing system applies a penalty if the mine’s consumption profile shows a history of overages, and a bonus in the opposite case.  

To help mines keep these costs to a minimum, Meglab has developed a system to monitor energy consumption and to reduce costs by using emergency generators in particular cases to reduce energy consumption from Hydro-One. 

Meglab has implemented this cost-saving system at Borden Mine, where emergency generators were used to top up their electricity consumption in order to avoid overages during peak periods and keep their billing to a minimum.

The system is capable of powering the mine in three different modes, based on the data it receives from its communication system:  

• In Hydro Mode, the generators are not activated and the mine is powered solely with the energy received from Hydro One.  
• In Island Mode, the mine is powered using only the energy produced by the generators.  
• In Parallel Mode, the mine receives energy from both Hydro One and its generators. 

The generators can be either set to produce a specific constant amount of energy or can be controlled by a PID (Proportional-Integral-Derivative) to maintain the amount of energy required by the mine.  We also added Schweitzer SEL relay to monitor energy consumption and control the electrical substations from distance. 

With this system, Borden Mine has seen a decrease in their electricity costs, as it allows them to monitor consumption in real time and reduce it by using generators during peak periods, or if they’ve reached their Hydro One electricity cap.  The data is displayed and controlled in real time in both the customer’s and Hydro One’s operator interfaces.  The system can be controlled remotely, which makes it much safer for workers.

There are certain time limitations to this method.  The system must be launched before the maximum electrical capacity defined in the contract is reached.  The users must also collaborate with their supplier in order to adjust the settings and to set-up the generators to work alongside the electricity provider.

There are also some technological limitations.  The system must meet the very demanding electrical protection and safety criteria imposed by Hydro One, along with their speed and stability of communication criteria, which includes a reaction time of a few milliseconds.  This means that a stable network must be in place to seamlessly transfer data. To meet these strict demands, Borden Mine needed an alternative solution to data transfer by cellular network as it did not have enough coverage.

To tackle these challenges, Meglab developed a system made up of different components.  They used a 25KV motorized switch and a SEL-421 relay at the entrance of the mine to protect the network and to serve as an interface to exchange data and commands between Hydro One and the mine.  Meglab also used a 25K zig-zag grounding transformer protected by a SEL-751A relay as well as a PLC and HMI interface to operate the whole system.

To communicate with each other, the main components use a cellular antenna to provide coverage for data exchanges between the mine site and Hydro One.  With coverage in place, the SEL-421 relay is able to communicate with Hydro One’s facilities and the SEL-751 relay at the mine site using Mirrored Bits through fiber optics.  The SEL-751 relay is then able to communicate with the generators by dry contacts, and with the SEL-751A relay protecting the zig-zag grounding transformer and the SEL-421 relay protecting the entrance using Mirrored Bits through fiber optics.  The PLC (programmable logic controller) interface communicates with the generators by Modbus TCP and with the Hydro-One operator interface by Distributed Network Protocol (DNP3) on a Long-term Evolution (LTE) or 4G network.

This highly adaptable and constantly evolving system has proven to reduce costs and can easily be implemented on other sites.  More functionalities can be added later on to better meet more specific needs and situations.  As the needs of mine companies evolve, Meglab continues to push to create solutions to optimize production, reduce costs and ensure a healthy and safe environment for all their clients.