Do you understand Loadshedding - Loadshedding explained

1. What is load shedding?

Loadshedding is a measure of last resort to prevent the collapse of the power system country-wide. When there is insufficient power station capacity to supply the demand (load) from all the customers, the electricity system becomes unbalanced, which can cause it to trip out country-wide (a blackout), and which could take days to restore. When power is insufficient, Eskom can thus either increase supply or reduce demand to bring the system back into balance. As the difference between supply and demand becomes small, we refer to the system becoming “tight”. This implies that action has to be taken to prevent the system from becoming unstable.
Eskom normally takes a sequence of steps to keep the system stable and to avoid load shedding. The steps include first asking large customers to reduce load voluntarily. However, if several power station units trip suddenly and unexpectedly, we may have to skip those steps and go straight to loadshedding to prevent the system from becoming unstable.
Scheduled loadshedding is controlled by way of sharing the available electricity among all its customers.
By switching off parts of the network in a planned and controlled manner, the system remains stable throughout the day, and the impact is spread over a wider base of customers. Loadshedding schedules are drawn up in advance to describe the plan for switching off parts of the network in sequence during the days that loadshedding is necessary.
On days when loadshedding is required, the networks are switched off according to the predetermined plan, to ensure that, as far as possible, customers experience loadshedding in accordance with the published loadshedding schedules.
In exceptional circumstances, if scheduled loadshedding is not achieving the required load reduction and/or unexpected emergencies or failures occur, then System Control Centres will shed load outside the published schedules by using emergency switching in order to protect the network.
Such events are rare, but if a state of emergency loadshedding is declared, then all customers can expect to be affected at any time, and the planned schedules may not necessarily apply.