Introducing an easy to install device which seeks to make load-shedding a problem of a bygone era. This simple device allows Electricity Supplier to limit electricity usage by all South African households, while allowing the households to still enjoy lights, TV and a cup of tea.


1. The Problem

Currently, Electricity Supplier is struggling to generate enough electricity for normal, unhindered use by
the whole country.
In winter, for example, geysers, lights, heaters and/or stoves are all turned on simultaneously
by a vast number of households seeking warmth. There arises strain on the electrical grid –
Electricity Supplier’s supply capacity becomes in danger of being overwhelmed. There is a need then, to
reduce electricity consumption.
Electricity Supplier then resorts to load shedding.
Load-shedding is the disconnection of electrical power by Electricity Supplier in order to reduce electrical
consumption. The aim is to make sure that total electricity usage at any instant does not
threaten the Electricity Supplier’s supply capacity. Simply put, load-shedding is done to ensure that the
country does not use more electricity than it can produce.
According to a pre-planned schedule then, Electricity Supplier disconnects various communities at a time,
for a couple or several hours (Stages 1, 2 and 3).
Load-shedding, however, is a major problem, not to mention a major nuisance. It results in
blackouts. These blackouts create opportunities for crime and further increase danger of
house fires as people tend to improvise in their lighting and cooking.

2. Current Solutions

The following are current solutions in use in the country:

i. Remote switch off

The general principle of operation:
Specific high-energy consuming appliances are targeted and disconnected by the
utility company (Electricity Supplier), e.g. geysers and pool pumps.

Reconnection is up to the schedule/discretion of the Electricity Supplier.
The user has no say in which appliance to switch off – the decision is totally up to
Electricity Supplier.

ii. Electrical smart-meters

The general principle of operation:
If a house uses more electricity than a certain communicated prescribed limit, Electricity Supplier
repetitively disconnects power supply to that house for a certain time period. During
that time period, that house must reduce electrical supply by turning off some
appliances. At the expiry of that time, if the house is still using more electricity than the
prescribed limit, Electricity Supplier cuts disconnect the house for an extended period of time.
The house is then without power until remotely reconnected by Electricity Supplier.

Reconnection is up to the schedule/discretion of the Electricity Supplier.

3. Introducing the Load-Limiting Device (LLD) Solution

An energy limiting device which is operable by the combined effort of Electricity Supplier (the energy supplier
party) and the user (the energy consumer party) to limit energy consumption of a house.

3.1. A Simple Box




The device comes in the form of a simple box which is installed before the distribution box of
a house. Installation is replicated in each and every house.

The box comprises:

- A “command signal” receiver (GSM module);
- A current-limiting circuit;
- An information display screen;
- A warning alarm (visual/audio);
- A local reset button; and
- A tamper-proof enclosure.

3.2. Principle of Operation

The box has two modes of operation: a normal mode and a current limiting mode.

3.2.1. Normal Mode

Normal mode allows normal, unhindered usage of electricity by the house. The box simply
acts as a passage for electricity to flow. The box leaves any current regulation to the
distribution box.

3.2.2. Load-Limiting Mode

Load-limiting mode allows restricted usage of electricity by the house. The box now acts as a
“throttle” for electrical current, limiting the current to a certain threshold. In the present
proposal, this threshold is 20A. The threshold may, of course, be varied as per need.

4. Functioning of the box

The point of departure is during normal operation, when houses in areas A, B, C, and D are
enjoying normal, unhindered usage of electricity.

• Strain arises on the grid. Electricity Supplier wishes to ease the strain by limiting electricity usage.
• Electricity Supplier then targets area C, according to a pre-planned load-management schedule.
• Electricity Supplier sends batch SMS’es, each SMS going to a box in each respective house in area C. The SMS is a command: “Enter Load-Limiting Mode at 20A”.
• The SMS is received by each box, and immediately, the box starts flashing/beeping as
a warning to the inhabitants of the house (the users) that load-limiting must be effected.
In short, reduce load consumption immediately.
• The warning lasts for a period of 1 minute (period can be varied).
• The box then enters load-limiting mode at 20A.
• If the users have not switched off enough appliances, such that the load consumption
in the house is still greater than 20A, immediate disconnection occurs LOCALLY (i.e.
the box cuts off supply to the house). Electricity Supplier is not involved anymore – the box simply
functions automatically, on its own.
• The users then realize that the house is drawing too much electricity. They disconnect
more appliances. Thereafter, the press the reset button on the box.
• Reconnection is immediate. The box, still in load-limiting mode, checks electricity
usage again. If usage has fallen to less than 20A, the box continues supplying the
house with limited electricity. If the usage is still over 20A, immediate disconnection
occurs again and will continue to occur until the house draws less than 20A of current.


5. Security – The Tamper-Proof Enclosure

The enclosure of the box contains sensors within it, so as to maintain the integrity of the box.
In cases of tampering, an alarm signal is sent to the Electricity Supplier. Electricity Supplier then decides on what to
do. Immediate disconnection of the transgressing house can be affected, pending further
investigation by Electricity Supplier officials.

6. Advantages of the Load Limiting Device v. Load-shedding

• Rather than total disconnection, there is always electricity available, although in
limited supply. So, houses still have lighting, TV, use of kettle, stove or any other
appliance, up to the prescribed limit (20A).

• Local disconnections eliminate the inconvenience of waiting for Electricity Supplier to reconnect
a user. This way, the user can learn the consumption capacity of their appliances
through trial and error, without fear of extended disconnection.

• The user has discretion in how to use electricity, provided that they do not surpass
the prescribed limit.

• A timely warning is given to the user when entering load-limiting mode, allowing the
user time to select which appliances to switch off.

• Relatively more areas can be targeted for load-limiting, thereby increasing energy
saving capacity.

• Streetlights can be kept on, owing to the amount of energy saved by targeting a lot of
areas at a time, thereby avoiding blackouts and reducing criminal opportunities.

• The display screen keeps the user informed, allowing the user to see the mode of
operation and instantaneous current usage of the house.

Installation is the simple mounting of the box to a wall, and connection of the box to the
existing circuitry.

Illegal by-passing of the box can be easily spotted, as usage patterns will show high
electricity usage during load-limit hours.

• The box is tamper-proof, making it reliable to Electricity Supplier in serving its function.

7. Patent Pending

The Load-Limiting Device (LLD) Solution is in the process of being patented. A provisional
patent application number 2015/00611 has been filed at the South African patent office.
A complete patent application is being prepared by the patent agents of LSNM, to be filed
within the month (October 2015).

Patent Pending The Load-Limiting Device (LLD) Solution is in the process of being patented. A provisional patent application number 2015/00611 has been filed at the South African patent office. A complete patent application is being prepared by the patent agents of LSNM, to be filed within the month (October 2015).

Contact Person

Roelof Louw

Cell: 082 088 4865


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