Load shedding system is a systematic approach to balance the demand and supply of electricity within a defined area or grid. When electricity demand exceeds the power source’s ability to supply it, the load shedding system triggers an action to balance the load requirement by disconnecting the non-critical load defined in the shedding system.
Difference between total blackout and load shedding.
A blackout condition of power outage in which no power source is available to supply power to the load. The inability to maintain the balance of demand and supply of electricity can lead to a total blackout. In contrast, as mentioned earlier load shedding is a controlled process meeting power source capacity by disconnecting noncritical load.
The basic requirement of implementing a load shedding.
- Interfacing electrical parameters such as voltage, current, Active power, Apparent power, frequency, etc to a PLC-based automation system.
- Identification of noncritical load.
Working of Load Shedding.
Consider the following SLD as mentioned in Figure 1 which shows three power generating stations namely PS-1, PS-2, and PS-3 each having generation capacity of 5MW, 5MW, and 10MW respectively, and four loads Load-1, load-2, load-3, and load-4 connected with them with common Bus-A.
Similarly, criticality of the mentioned load is shown in Figure 2
Consider a situation in which generating station PS-3 suddenly reduces its load generation to 5MW then there will be a condition of unbalance between the power source and load requirement so the load shedding system will sense it and it will trigger the load shedding and disconnect the lowest critical load i.e. load-1 (Figure 2). After the certain time limit, then it will again check for the unbalance condition and if required it will shed the second lowest noncritical load from the system and this will continue to happen till power source and the load becomes equal or power source is higher than load.
Verni nice, described in well manner.