Electrical load shedding techniques are used to manage the demand and supply balance in a power system during times of high demand or generation constraints. These techniques are implemented to prevent widespread blackouts and maintain system stability. The specific methods used for load shedding may vary depending on the power grid and its infrastructure, but some common types of electrical load shedding techniques include:
Manual Load Shedding: This involves human operators deciding which areas or consumers to disconnect from the power supply during emergencies. It is a simple and immediate response to prevent system collapse, but it relies on human judgment and can be less precise.
Static Load Shedding: Static load shedding is based on predefined priority lists or load shedding schedules. Certain areas or consumer groups are designated as lower priority, and they are automatically disconnected from the grid when power demand exceeds supply capabilities.
Dynamic Load Shedding: This technique involves monitoring the real-time system parameters and making decisions on load shedding based on the current conditions. Advanced control systems use algorithms to dynamically determine which loads should be shed to maintain grid stability.
Under-Frequency Load Shedding (UFLS): UFLS is a protection scheme used to prevent system collapse during significant drops in frequency caused by sudden generation loss. When frequency falls below a certain threshold, predetermined loads are automatically disconnected to restore the balance.
Economic Load Shedding: Economic load shedding involves shedding non-critical loads or reducing the supply to certain consumers during peak demand periods. This method is usually implemented in industrial settings where specific processes can be temporarily halted without major consequences.
Load Curtailment: In load curtailment, certain consumers or loads are requested to voluntarily reduce their electricity usage during times of high demand. This approach is common in demand response programs, where consumers are incentivized to lower their consumption during peak periods.
Load Shedding through Interruptible Contracts: Some large industrial consumers have interruptible contracts with their utility providers. These contracts allow the utility to curtail power supply to these customers during peak times in exchange for reduced rates.
It's important to note that load shedding is generally considered a last resort measure, and utilities will try to manage demand through other means, such as grid interconnections, energy storage systems, and demand-side management, before resorting to load shedding. The specific techniques used and their implementation can vary widely based on the characteristics and capabilities of the power grid and the regulatory environment of each region.