Keemin have developed a load-shedding device that has numerous uses in many environments all of which benefits the end user.

In industry the unit can be used to limit maximum demand of an installation and can save many thousands of dollars over a year. Maximum demand is paid for every month and is calculated on the maximum demand an installation has reached in the past. Keemin can get you maximum demand re-set to a lower level saving money each and every bill and can help to maintain the lower maximum demand by the use of load-shedding.

In a domestic application it can prevent the nuisance tripping of supply capacity control devices. Well suited for premises that use slab heating and the total demand of the heating can exceed the available capacity.

The unit is user friendly and fully configurable. Current status is readily viewable via its interactive display.

How we do it!

By constantly monitoring the current drawn by an installation and comparing it to the maximum level set, the unit will start "shedding" low priority / non critical loads to keep the amperage below the desired maximum value. Once consumption drops, the loads are switched back on.

Using a current transformer to monitor the current drawn allows the flexibility to monitor installations drawing 10's of amps through to 1000+ amps. Current transformers are inexpensive, reliable and come in a wide range of ratio's to suit all applications.

Some industrial or agricultural examples may include:

A storage freeze can wait for the brief period of time a blast freezer is in use before being turned on. If both these units run simultaneously and are responsible for the existing maximum demand tariff that is being paid for month-in month-out there is an advantage in temporarily delaying the starting of the storage freezer. Once demand has dropped off, the storage freezer is automatically bought back on-line.

Often an installation will have multiple compressors; maximum demand can be successfully limited by temporarily shutting down a compressor or delaying the start of one. The cool room can still keep the produce with in acceptable temperature limits and the product is not affected during the short periods of time that a compressor is shut down until demand drops.

In the agricultural field, selected cool room compressors could be temporarily shut down while irrigation pumps are running and full capacity returned once the irrigation is complete. No harm to the stored produce, but big savings by means of a lower maximum demand.

Domestic installations with slab heating.

Our load-shedding unit can be installed in domestic installations to prevent nuisance tripping of a supply capacity control device. After consultation, careful planning and configuration, all areas of the home can be adequately heated without tripping the supply capacity control device.

Options:

Keemin Electrical can supply load shedding units as a complete package. We will handle your project from initial consultation through to installation, configuration and fine tuning. An operating manual and electrical drawings are supplied for each project.

Keemin Electrical can also supply pre-programmed units and all required components for your application ready for installation by your preferred Electrical Contractor. As the units are fully configurable fine tuning on-site is possible by your Electrician. On and off site training plus phone support is available.

Basic Settings.

Some of the basic on-site configurable settings are:

Maximum Amps - Current drawn for shedding to begin

Time before shedding starts - How long the maximum amps are drawn or exceeded for before load shedding starts

Add load Amps - How many amps below the maximum amps setting before loads are turned back on. (This is set to prevent continual cycling of loads shed so the maximum setting isn't exceeded when a shed load is turned back on).

Add load time - How long the current drawn drops below the 'Add load Amps' value before turning the loads back on.

Here is a link to the user manual.

Please contact us via email or by phone on (03) 5368 2001 for more information.

A Mitsubishi Alpha Programmable Logic Controller is used to do the load-shedding. It is user friendly and the screen can display various pages that contain useful information about what the unit is doing.

This image is of a controller, relays and power supply mounted in an NHP 18 module enclosure. Also shown is a current transformer and tranducer used to measure and convert the amperage drawn by an installation.

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This image is of a two phase domestic installation. The load-shedding units successfully control 50kW of slab heating.

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Keemin Electrical has worked closely with NHP to develop the loadshedding unit. NHP stocks and supplies the necessary components required to build each unit.